Rapid in vitro activation of corpora allata by extracted locust brain allatotropic factor

Brains of young (newly emerged) adult female locusts (Locusta migratoria migratorioides) and of mature (> 9 days old) locusts contain an extractable allatotropic factor, soluble in 100% methanol and in distilled water. This factor stimulates juvenile hormone III (JH III) synthesis and release from corpora allata (CA) that have been excised from donor locusts and then incubated with (radiolabeled methyl)-methionine in vitro in its presence. In addition to JH III, which is the major product synthesized by the CA, other hexanesoluble, radiolabeled compounds–-more polar than JH III–-are also released when CA are incubated in vitro. The activation of CA by the allatotropic factor is rapid and quickly declines when the factor is removed from the medium. Corpora allata excised from young females are marginally active and can be activated by brain allatotropic factor to less of an extent than CA of mature locusts. The content of allatotropic factor in brains of mature locusts is higher than that ascertained in brains of young females. Allatotropic factor is also present in the corpora cardiaca.     

Enhancement by farnesol and farnesoic acid of juvenile-hormone biosynthesis in induced low-activity locust corpora allata

Exogenous farnesol or farnesoic acid (FA) stimulates juvenile hormone III (JH III) biosynthesis by isolated corpora allata from Locusta migratoria in a dose-dependent manner. Farnesol and FA also stimulate a dose-dependent accumulation of substantial amounts of methyl farnesoate (MF), identified by gas chromatography-mass spectroscopy (GCMS) analysis, in the corpora allata. Lower quantities of MF were found in the incubation medium. Corpora allata, denervated 2 days prior to assay, showed low spontaneous rates of JH biosynthesis which were stimulated by farnesol and FA. The dose-response curves for control and denervated corpora allata were similar. During oocyte maturation the rate of farnesol and FA stimulation of JH biosynthesis increased gradually. However, after transection of nervus corporis allati 1 (NCA-1), the rate of stimulated JH synthesis was maintained at preoperative levels. Although the spontaneous rate of JH biosynthesis decreased rapidly after NCA-1 transection, denervated glands could still be stimulated by farnesol or FA to produce large amounts of JH. These results suggest that the low spontaneous rate of JH biosynthesis in denervated corpora allata is not caused by inhibition of the final steps of JH biosynthesis.     

Control of C-16 juvenile hormone biosynthesis in active corpora allata of female African locusts

Summary

Corpora allata from 8-day-old female Locusta migratoria, during the phase of yolk deposition, exhibit high rates of C-16 juvenile hormone (JH) biosynthesis. The effect of different potential factors which may be involved in the regulation of corpora allata activity is reported. The biosynthetic activity of corpora allata was determined by radiochemical assay.

In maturing females, no changes in corpora allata activity are detected during one daily cycle. Starvation reduces JH biosynthesis only 3 days after the beginning of the food deprivation. Suppression of the median neurosecretory material by electrocoagulation of the internal cardiaca tract (TCC-I) does not disturb JH biosynthesis whereas the transection of the allata I nerve fibres (NCA-I) or the electrocoagulation of the lateral neurosecretory pericarya results in a rapid decline of JH biosynthesis. These data indicate that the median and lateral allatotropins are different, and that only the lateral neurosecretory material exerts an allatostimulating action on corpora allata at the time of vitellogenesis. The corpora allata response to the median allatotropin changes during oocyte growth. C-16 JH and/or 20-hydroxyecdysone treatments in vitro (addition in the culture medium) and in vivo (injection in female) do not influence JH production in our experimental conditions.     

Effect of high potassium concentrations on juvenile hormone release in vitro from corpora allata of Locusta migratoria

ABSTRACT. Incubation of corpora allata (CA) from adult females of Locusta migratoria (L.) in vitro in medium with a potassium concentration of 50 mM results in an elevation of the rate of juvenile hormone (JH) release. This elevation is however delayed, becoming apparent after the glands have been returned to low concentration of potassium but it is also prolonged, lasting up to 270 min. The elevation is initially modest but becomes more marked with time. The response of glands to high concentration of potassium is heterogeneous and appears to some extent to be a function of the initial rate of JH release of the glands. Glands starting with low rates of JH release are stimulated strongly by potassium, those with high rates of JH release much less so. Co-incubation of glands with high concentration of potassium and with calcium channel blockers (both organic and ionic) prevents the elevation of release rates otherwise consequent on high concentrations of potassium.     

Ultrastructural changes in corpora allata during a cycle of juvenile hormone biosynthesis in embryos of the viviparous cockroach, Diploptera punctata

We have observed changes with time in the fine structure of corpora allata (CA) during a known cycle of increasing and decreasing juvenile hormone (JH) synthesis in late embryos of Diploptera punctata. A previous report showed that rates of JH release were relatively low in 28-day-old embryos, but CA activity subsequently rose linearly to a peak on about day 42, and thereafter steadily declined to a low level on day 64 just before birth (Holbrook et al., 1997). We now show that, regardless of rate of JH synthesis, CA cells are large and replete with organelles which nevertheless exhibit variable morphology in embryos of different age. Highly active CA cells on day 40 contain abundant ring-form mitochondria, whereas CA cells of low activity on days 28 and 64 contain mitochondria that are rod-shaped or globular. Mitochondrial cristae were scarce and indistinct on day 28 but numerous and well developed on day 64. Endoplasmic reticula (ER) are rare on day 28 and appear in increasing numbers when CA activity rises. On day 40, ER are abundant and often exhibit a whorl-like appearance which is not observed on day 28. After day 44, when biosynthetic activity is declining, whorls of ER gradually decrease in number and are ultimately replaced by vesicular smooth ER on day 64. Neurosecretions are found only after day 38, by which time rates of JH synthesis have increased substantially from those of day 28. Except for membranous autophagic vacuoles, which are frequently found when ER whorls disintegrate as rates of JH synthesis decline toward birth, most autophagic vesicles such as multivesicular vesicles and dense bodies occur only sporadically among CA cells at all examined ages. We conclude that synchronous autophagy of exhausted organelles, which results in atrophy of CA cells and long-term arrest of JH synthesis in adult females of D. punctata, does not occur in embryos. The slow cyclic change in rate of JH synthesis in embryonic CA is most likely due to asynchronous autophagic activity and to alterations in certain unique features of intracellular organelles.     

Precocene-induced necrosis and haemocyte-mediated breakdown of corpora allata in nymphs of the locust Locusta migratoria

Light and electron microscopic studies, including the use of the vital dyes trypan blue and acridine orange, indicate that the topical application of precocene II rapidly triggers degenerative processes in the corpora allata (CA) leading within a few days to the virtual disappearance of the parenchymal cells of these glands. The following sequence of events was observed: 1) Within 2 h, many of the cells in fixed nymphal specimens showed increased electron density. During the next few hours, they decreased considerably in volume (shrinkage necrosis). Intercellular spaces increased simultaneously. Although a variable number of cells remained electron lucent, they showed nuclear and cytoplasmic degeneration later on (coagulative necrosis). 2) Haemocytes arrived at the CA sheath and invaded the CA in large numbers after 12 h. 3) CA cells became increasingly necrotic, and cell fragments were budded off and were phagocytosed most noticeably after 1 to 3 days. Thereafter no CA parenchyma remained. 4) Haemocytes dispersed.     

蝗虫微孢子虫对东亚飞蝗卵黄原蛋白含量的影响

采用免疫学方法,对东亚飞蝗Locusta migratoria manilensis感染蝗虫微孢子虫Nosema locustae后体内卵黄蛋白含量的变化进行了研究。结果表明,感病蝗虫与对照健虫相比,卵黄发生有严重障碍,脂肪体和卵巢中卵黄原蛋白或卵黄蛋白含量极低,导致感病雌虫丧失产卵能力。脂肪体中卵黄原蛋白含量最高峰健虫为18.7 mg/mL,而病虫只有4.7 mg/mL;血淋巴中卵黄原蛋白含量最高峰健虫为7.6 mg/mL,而病虫只有2.6 mg/mL;卵巢中卵黄蛋白含量最高峰健虫为73.4 mg/mL,而病虫只有4.9 mg/mL。     

The influence of substrate concentrations on the rate of insect juvenile hormone biosynthesis by corpora allata of the desert locust in vitro

The rate at which isolated corpora allata of adult female Schistocerca gregaria incorporate [(3)H]farnesenic acid and [(14)C]methionine into C(16)juvenile hormone in vitro was examined at different concentrations of farnesenic acid, methionine, O(2) and H(+) ions. Maximum juvenile hormone biosynthesis is obtained at a farnesenic acid concentration of 20mum. The range of optimum l-methionine concentrations (0.1-0.4mm) encompasses the physiological concentration of this substrate in the haemolymph. Hormone biosynthesis is dependent on O(2), but is not stimulated by hyperbaric oxygen tension. The glands had a maximum synthetic activity at pH8.0, but their activity was more reproducible in the the physiological range pH7.0-7.5. At pH6.5 and less, the synthetic ability was considerably decreased. The relative incorporations of the labelled substrates into methyl farnesoate and C(16) juvenile hormone indicate that [(3)H]farnesenic acid comes into isotopic equilibrium within the gland more rapidly than [(14)C]methionine. The incorporations into methyl farnesoate become stoicheiometric after 20min incubation and into C(16) juvenile hormone after a further 10min. Labelled juvenile hormone is detectable after 10min incubation and the rate of incorporation is constant for up to 4h. It is proposed that the described method may be usefully employed to assess the physiological changes in the enzymic competence of the glands to effect the last two stages in C(16) juvenile hormone biosynthesis.     

SERINE proteinase like activity in apolipophorin III from the hemolymph of desert locust, Schistocerca gregaria

Apolipophorin III (apoLp-III) has been known as a lipid transport protein of insects. Recent studies indicated the involvement of apoLp-III in immune reactions and in the control of cell destruction, but no enzymatic activity has so far been detected. In the present study, a protease from the hemolymph of Schistocerca gregaria was purified to homogeneity and its enzymatic activity was examined. Identity as chymotrypsin-like proteinase was established by its high affinity toward bulky aromatic substrates and its catalytic specificity for amide or ester bonds on the synthetic substrates, Suc-Ala-Ala-Pro-Xaa-AMC (where Xaa was Phe, Tyr, Trp, and Lys, and AMC is 7-amino-4-methyl-coumarin) and thiolbenzyl ester substrate Suc-Ala-Ala-Pro-Phe-SBzl. The sensitivity for serine protease and chymotrypsin-specific covalent inhibitors, PMSF, TPCK, and noncovalent inhibitors SGCI, showed that it is a chymotrypsin-like proteinase. It showed its maximum activity at pH 8.0 and 55°C for the hydrolysis of Suc-Ala-Ala-Pro-Tyr-AMC. According to similarities in the amino terminal sequence, molar mass (19 kDa) and retention on reversed-phase analytical high-performance liquid chromatography (HPLC) column, this protein is S. gregaria homologue of Locusta migratoria apoLp-III. Our data suggest that apoLp-III also has an inherent proteolytic activity. Results indicated that S. gregaria apoLp-III is a good catalyst and could be used as a biotechnological tool in food processing and in agricultural biotechnology.     

低温和变温诱导对飞蝗胚胎发育的影响

【目的】飞蝗Locusta migratoria(Linnaeus)是我国乃至全世界广泛发生的重要农业害虫,其种群暴发会给农作物造成重大为害和减产。飞蝗种群发生动态受低温及变温的影响,但低温和变温如何作用于胚胎发育和是否诱导胚胎滞育的发生,目前尚不清楚。【方法】本文在对飞蝗胚胎发育特点观察鉴定的基础上,研究了胚胎发育中期恒定低温诱导、诱导后恢复、发育中期变温诱导及发育早期低温诱导等条件对胚胎发育进程的影响。【结果】研究发现,胚胎发育起点温度下非致死温度7.5℃处理促使胚胎发育历期变异增加,而25~30℃高温下胚胎发育整齐。7.5℃处理时间长短对胚胎发育影响不明显,但该低温培育时间长短影响后期常温下的胚胎发育,即7.5℃下长期低温可能促进25℃或30℃下的胚胎的发育。25℃以下变温温度影响胚胎发育进展,但影响胚胎发育的限制因子主要是发育起点以上温度。【结论】因此,温度作为单一环境因子,其特定的低温和变温处理不仅没有诱导胚胎滞育的发生,反而促进后期胚胎在常温下的发育。本研究结果对揭示温度变化对个体发育和种群动态影响及预测飞蝗种群发生有重要的指导意义。     

Biological,radiochemical and physicochemical evidence for the low activity of disconnected corpora allata in locust

The rate of juvenile hormone biosynthesis by locust corpora allata after transection of the nervi corporis allati 1, was measured in vitro using both radiochemical assay and gas chromatography—mass spectroscopy analyses. Incubations in different culture media or in pure haemolymph result in a low rate of juvenile hormone biosynthesis by disconnected glands. In vivo studies using juvenile, chromatotropic and gonadotropic effects of the corpora allata confirm the low activity of the disconnected glands. Furthermore, animals with disconnected corpora allata appear to be more sensitive to corpora allata implantation than control hosts.     

Ultrastructure of corpora allata of known activity during the vitellogenic cycle in the cockroach Diploptera punctata

Summary Ultrastructure was correlated with rates of juvenile hormone synthesis in corpora allata from females of the viviparous cockroach Diploptera punctata at seven daily intervals during the first vitellogenic cycle. Synthetic activity of the glands was determined by in vitro radiochemical assay before the glands were fixed for electron microscopic analysis. The cycle in rates of juvenile hormone synthesis progressed from about 20 pmol h^-1 per gland pair (oocytes 0.60 mm long) to a maximum mean rate of 140 pmol h^-1 per pair (oocytes 1.40–1.47 mm long) and declined to about 20 pmol h^-1 per pair at ovulation (oocytes about 1.65 mm long). Conspicuous ultrastructural changes occurred with changing synthetic rates. In glands with increasing rates of synthesis, mitochondria showed less electron-dense matrix, greater diameter and more irregular shape. Smooth endoplasmic reticulum changed from easily seen to obscure tubules, networks, and vesicles. Rough endoplasmic reticulum appeared in longer, more curved segments. Newly formed autophagic vacuoles appeared in all glands of highest activity rates. In glands with decreasing rates of synthesis, the mitochondrial matrix became denser, width smaller, and shapes less irregular. Smooth endoplasmic reticulum again appeared tubular and distinct. Golgi complexes were more conspicuous. Rough endoplasmic reticulum in whorls and large numbers of autophagic vacuoles continued to be present.This work was supported by USPH Grant AI 15230. We thank Kuen-Kuen Chan for skillful and thoughtful technical assistance     

Identification of LmUAP1 as a 20‐hydroxyecdysone response gene in the chitin biosynthesis pathway from the migratory locust,Locusta migratoria

In Locusta migratoria, we found that two chitin biosynthesis genes, UDP N‐acetylglucosamine pyrophosphorylase gene LmUAP1 and chitin synthase gene LmCHS1, are expressed mainly in the integument and are responsible for cuticle formation. However, whether these genes are regulated by 20‐hydroxyecdysone (20E) is still largely unclear. Here, we showed the developmental expression pattern of LmUAP1, LmCHS1 and the corresponding 20E titer during the last instar nymph stage of locust. RNA interference (RNAi) directed toward a common region of the two isoforms of LmEcR (LmEcRcom) reduced the expression level of LmUAP1, while there was no difference in the expression of LmCHS1. Meantime, injection of 20E in vivo induced the expression of LmUAP1 but not LmCHS1. Further, we found injection‐based RNAi of LmEcRcom resulted in 100% mortality. The locusts failed to molt with no apolysis, and maintained in the nymph stage until death. In conclusion, our preliminary results indicated that LmUAP1 in the chitin biosynthesis pathway is a 20E late‐response gene and LmEcR plays an essential role in locust growth and development, which could be a good potential target for RNAi‐based pest control.     

Chill injury in the eggs of the migratory locust, Locusta migratoria （Orthoptera： Acrididae）： the time-temperature relationship with high-temperature interruption

Abstract Mortality of the overwintering egg of the migratory locust, Locusta migratoria L. , was attributed to chill injury because of its occurrence well above the egg's super cooling point. In this study, two parameters, upper limit of chill injury zone (ULCIZ) and sum of the injurious temperature (SIT), were used to examine the locust egg's cold hardiness. The value of ULCIZ for the locust egg is 1.06 ± 0.54°C, and the SIT is -329.7 (hour · degree). The superoxide dismutase (SOD) and catalase (CAT) activities changed dramatically after cold stress, indicating that oxygen and hydroxide free radicals are probably efficiently detoxified at low temperatures. It was suggested that the nature of chill injury in locust egg might be a complex of metabolic disorder and a non-proportional decrease in enzymatic reaction and transports, because the LDH activity at low temperature increased significantly and the ATPase activity decreased with prolonged duration of exposure to low temperatures. The results from high temperature interruption revealed that the high temperature intervals significantly increased the survival of locust eggs.     

Measurements of locomotor activity in hatchlings of the migratory locust Locusta migratoria: effects of intrinsic and extrinsic factors

Abstract. The effects of intrinsic and extrinsic factors on locomotor activity in crowd‐reared first‐stadium nymphs of the migratory locust Locusta migratoria are investigated under continuous light conditions using an actograph apparatus. Nymphs show monomodal or bimodal patterns of locomotor activity with respect to the time after the start of measurements, depending on the age. Locomotor activity is suppressed by the presence of grass in nymphs aged 0–2 days old but a peak of activity observed shortly after hatching is not suppressed. The results suggest that newly‐hatched nymphs may try to disperse from the hatching site. Nymphs show higher locomotor activity levels under moist conditions than under dry conditions during the first 5‐h period of measurements. This enhanced locomotor activity may constitute attempts to avoid high humidity. Under dim‐light conditions (2 × 10^?2 Wm^?2), locomotor activity is suppressed during the first half day and increases to a high level thereafter in both grass‐fed and unfed individuals. This increased activity might indicate a possible involvement of circadian rhythms. Background colour has no significant effect on the locomotor activity. The present study provides new aspects of behaviour in nymphs as well as baseline data for behavioural analysis of locust locomotion in relation to phase polyphenism.     

Rates of Juvenile Hormone biosynthesis and degradation during reproductive development and diapause in the boll weevil, Anthonomus grandis

Abstract. The role of Juvenile Hormone (JH) during reproductive development and diapause was investigated in the boll weevil, Anthonomus grandis Boheman (Coleoptera: Curculionidae). JH sythesized by corpora allata (CA) in vitro of A.grandis was identified as JH-UJ by high-performance liquid chromatography and by conversion to the methoxyhydrin. Optimal conditions for the use of a short-term assay in vitro were established to examine profiles of CA activity. In addition, rates of JH degradation by JH-specific esterase were determined. Patterns of CA and JH-esterase activity during reproductive development and the diapause state were established with laboratory-reared reproductive weevils and diapausing weevils collected as larvae and pupae in the field after the cotton-growing season. The results indicate that JH production is elevated in reproductive females whereas males and winter field-collected females show no CA activity. Vitellogenin concentrations in haemolymph and rates of oviposition were studied in relation to CA activity and JH degradation. An attempt to induce diapause in the laboratory failed.     

Effects of starvation and oviposition activity on the reproductive physiology of the sweet potato whitefly, Bemisia tabaci

Abstract. We examined the effects of starvation and oviposition on the reproductive physiology of the sweet potato whitefly, Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae). In a first set of experiments, females were starved as well as denied the opportunity to oviposit. The combined amounts of vitellogenin and vitellin per female increased by 69% when they were removed from plants for 24 h, egg load increased two-fold in approximately 4.5 h. The lipid content, on the other hand, decreased significantly over an 8 h perod. Thus, vitellogenin synthesis and the formation of mature eggs do not seem to be limited by the lack of nutrient intake or the ability to oviposit. In a second set of experiments, females were restricted to either young leaves of melon plants (Cumis melo), that are preferred oviposition sites, or to old melon leaves, that are non-preferred oviposition sites. At the end of the experiment, females on the old leaves contained significantly higher amounts of vitellogenins and vitellins than females confined to young leaves. These comparisons were made relative to body weight. The data also indicate that females accumulated both vitellogenins and lipids when confined to old leaves, but did not do so on young leaves. These results are consistent with the hypothesis that females of B. tabaci explicitly discriminate against older leaves for oviposition. We argue that examinations of changes in egg load or the combined vitellogenin and vitellin content that accompany oviposition can provide better insights into the oviposition behaviour of B. tabaci.     

Influence of soil moisture on egg cold hardiness in the migratory locust Locusta migratoria (Orthoptera: Acridiidae)

Abstract.  The present study investigates the influence of environmental moisture on cold hardiness of the migratory locust, Locusta migratoria . The water content of locust eggs kept in soil at 30 °C varies according to the moisture content of the substrate. In turn, it can significantly affect the supercooling point of locust eggs (range from −26 to −14.8 °C) and the mortality when exposed to subzero temperatures. Environmental moisture influences the supercooling capacity of eggs and their survival at low temperature. When locust eggs of the same water content are exposed to subzero temperatures under different soil moistures, their mortality varies between short-time exposure and long-time exposure at subzero temperatures. Given a short-time exposure, mortality in wet soil is lower than in dry soil due to the buffering effect of soil water against temperature change. The pattern of egg mortality is reversed after long-time exposure at low temperature, suggesting that inoculative freezing may be an important mortality factor. It is suggested that interactions between soil moisture and low temperature can influence the cold hardiness of locust eggs, and partial dehydration is beneficial to over-wintering eggs of the migratory locust.     

Terminal stages in juvenile hormone biosynthesis in corpora allata of Diploptera punctata: Developmental changes in enzyme activity and regulation by allatostatins

The O-methyltransferase, which is responsible for the methylation of farnesoic acid in the corpora allata of Diploptera punctata, is a cytosolic enzyme. The activity of O-methyltransferase closely parallels JH biosynthesis in last instars and adult females. Because allatostatin 4 (AST 4) from D. punctata and callatostatin 5 (CAST 5) from Calliphora vomitoria can inhibit juvenile hormone biosynthesis, their effects on the activity of O-methyltransferase and epoxidase, the enzymes involved in the final two steps of juvenile hormone biosynthesis, were investigated in vitro. AST 4 can inhibit methyltransferase activity whereas CAST 5 stimulates it. AST 4 inhibits epoxidase activity slightly whereas CAST 5 inhibits it significantly (36%). Treatment of corpora allata with farnesoic acid (40 μM) can reverse the inhibitory effect of AST 4 and CAST 5 on JH release by corpora allata. Thus, allatostatins appear to exert their inhibitory effect on JH biosynthesis at least partially through inhibition of the activity of terminal enzymes. Two biosynthetic pathways for the conversion of farnesoic acid to JH may exist in corpora allata of D. punctata: the predominant pathway is farnesoic acid to methyl farnesoate, then to JH whereas the other, representing about 5–10% of total JH production, is farnesoic acid to JH III acid, then to JH.     

The effects of octopamine on juvenile hormone biosynthesis,electrophysiology, and cAMP content of the corpora allata of the cockroach Diploptera punctata

Summary Juvenile hormone production by the corpora allata of the adult female cockroach, Diploptera punctata, can be modulated by treatment with the biogenic amine, octopamine. Endogenous octopamine has been identified within the CA, using HPLC and electrochemical detection. Treatment with octopamine results in a sinusoidal, dose-dependent inhibition of JH biosynthesis by CA from day 2 virgin females, with maximal inhibition occurring at 10^-10 M and 10^-4 M. In day 4 and day 8 mated female corpora allata octopamine inhibited JH biosynthesis at 5·10^-5 M. Although the elevation of either cAMP or cGMP within the CA is known to be associated with an inhibition of JH biosynthesis, treatment with high concentrations of octopamine results in an increase in the level of cAMP but not cGMP. This effect is both dose- and time-dependent.Octopamine treatment also initiates changes in the passive membrane responses of the CA. Superfusion of CA with octopamine results in a pronounced hyperpolarization of CA cells and an increase in the electrotonic potential (indicative of the degree of electrical coupling between CA cells). This effect could be blocked by the octopamine receptor blocker phentolamine. Treatment with octopamine or phentolamine also blocked the hyperpolarization of CA cells normally associated with electrical stimulation of the axon tracts innervating the CA.We hypothesize that octopamine may be a natural neuromodulator of JH production by CA, regulating ion channels in CA cells themselves as well as release of the inhibitory neuropeptide, allatostatin, from the terminals within the CA.Abbreviations 4-AP 4-aminopyridine - CA corpora allata - CC corpora cardiaca - cAMP cyclic adenosine monophosphate - cGMP cyclic guanosine monophosphate - EDTA ethylenediamine tetraacetic acid - HEPES N-2-hydroxyethylpiperazine-N2-ethanesulfonic acid - HPLC high pressure liquid chromatography - IBMX 3-isobutyl-1-methylxanthine - JH juvenile hormone - ms millisecond - nA nanoampere - NCA I nervi corporis allati I - OCT octopamine - TEA tetraethyl ammonium