Presence of sialic acid in prothoracic glands of Galleria mellonella (Lepidoptera)

The presence of sialic acid (SA) in prothoracic glands (PGs) of Galleria mellonella was determined by the methods of electron microscopy (EM), histochemistry, spectrophotometry (SP) and electronic ionization (EI)-mass spectroscopy. Histochemical observations were carried out by the cationic dye ruthenium red (RR), staining with and without neuraminidase digestion in the larval stage. Neuraminidase-sensitive SA was demonstrated by the decrease in the amount of RR-binding following neuraminidase digestion. The total amount of SA was found to be 0.09016 mg g(-1) in dry tissue by spectrophotometric determination. EI-mass spectroscopy results confirmed the EM and SP observations. The fragmentation scheme derived from EI-mass analysis exhibited the presence of the lactonized form of Neu5Gc7, 9Ac(2). On the basis of the various pieces of evidence described above, it was firmly concluded that Neu5Gc7, 9Ac(2) molecules were present in PGs of G. mellonella.     

Steroid transport through the surface of the prothoracic gland cells in Galleria mellonella L.

Steroid transport through the cell surface of the giant polyploid prothoracic gland cells of Galleria mellonella L. was studied by an ultracytochemical method. The alkaloid digitonin, known to form a complex with all sterols having a free-OH radical in position 3, proved to be suitable for studying the interiorisation of moulting hormone precursors and the release of synthesized hormones. The results suggest that cholesterol uptake in the last larval instar occurs by macropinocytosis during the feeding period, while the release of the steroids produced by the gland occurs by reverse micropinocytosis mostly on days 5-7 of the instar. The two processes are not simultaneous. The intracytoplasmic localisation of the reaction product confirms the steroidogenic role of the prothoracic gland.     

Ultrastructural study of the postembryonic development of the neural lamella of Galleria mellonella L. (Lepidoptera)

Summary The neural lamella encapsulating the brain of the wax moth Galleria mellonella develops from a very thin (80–120 nm) layer in the first larval instar, resembling the basal lamina, to a thick (1–4 m) sheath composed of two zones in the seventh (last) instar. After its breakdown at the time of larval-pupal ecdysis the neural lamella is reconstructed in the pupa, 2–3 days before pupaladult ecdysis.The cells of the perineurium seem to be responsible for the formation of the neural lamella, both in the larva and pupa, even though its ultrastructure differs at these stages.This paper is dedicated to the memory of doc. dr hab. Andrzej B. Dutkowski who proposed this studyPreliminary results of these studies were presented at the XII-th Congress of the Polish Zoological Society, Pozna (Osiska, 1979)The authors previous surname was Dybowska. She wishes to express her gratitude to Prof. Aleksandra Przeecka for valuable assistance in the preparation of this paper. She is also greatly indebted to Joanna Koodziejczyk, M.Sc. for technical aid     

Juvenile hormone counteracts the action of ecdysterone on silk glands of Galleria mellonella L. (Lepidoptera : Pyralidae)

Morphological and physiological evidence is presented to show that ecdysterone (20E) and juvenile hormone (JH) directly affect the silk glands of Galleria mellonella (Lepidoptera : Pyralidae). Within 1 hr in a culture medium, 20E at 5 or 50 ng/ml stimulates, and at 5 μg/ml inhibits, RNA synthesis. Both these effects are obliterated with physiological (1 ng/ml) and higher doses of JH II or a juvenoid. Dipping of isolated larval abdomens in 0.32% 20E suppresses the rate of RNA synthesis in freshly dissected silk glands incubated in a hormone-free medium. The ultrastructure of silk glands shows functional regression, followed by histolysis within 72 hr after dipping. Both the reduction of RNA synthesis and the cytological changes are prevented when the abdomens receive JH II or a juvenoid simultaneously with 20E. Presence of JH II in the culture medium also enhances RNA synthesis in silk glands dissected from abdomens that had been treated with 20E. The results reveal that the effect of 20E is dose-dependent and may be prevented, and up to a certain point reversed, with JH.     

Electron microscopical-immunocytochemical evidence of ecdysteroids in the prothoracic gland of Galleria mellonella

Summary Fixation of prothoracic glands of Galleria mellonella with a solution containing saponin permits immunocytochemical staining of the entire gland. By this means ecdysteroids were demonstrated electron microscopically to be present in the hyaloplasm and microtubules.Supported by Sächsische Akademie der Wissenschaften zu Leipzig     

温度对大蜡螟生长发育和繁殖的影响

为明确不同温度对大蜡螟(Galleria mellonella L.)生长发育和繁殖的影响,在24℃、28℃和31℃三个温度条件下,采用人工饲料饲养观察了大蜡螟的生长发育和繁殖状况。结果表明,温度对大蜡螟发育历期、生长发育速率以及繁殖具有显著影响(P0. 05)。在24～31℃范围内,随着温度升高,各虫态发育历期缩短,幼虫体长增长加快,发育速率加快。在24℃下世代历期最长(47. 96 d),31℃下世代历期最短(33. 68 d)。在同一温度下,雄蛾的寿命明显较雌蛾的寿命长,但成虫寿命、产卵前期和产卵期均随着温度升高而缩短。在24℃下产卵量最高为2 781. 50粒/雌,而在31℃下产卵量最低为1 943. 17粒/雌。     

Two disulphide bridges are present in juvenile hormone binding protein from Galleria mellonella

The hemolymph juvenile hormone binding protein (JHBP) from Galleria mellonella contains two disulphide bridges/molecule and no free Cys residues. An alignment of primary structures of other Lepidopteran JHBPs indicates that Cys residues, equivalent to Cys10,17,151,195 in G. mellonella JHBP, maybe involved in -S-S- bridge formation.     

Detoxification of destruxins in Galleria mellonella L. larvae

1. Destruxins applied by intrahaemocoelic injection into Galleria mellonella larvae quickly accumulate in hindgut and are extensively metabolized by opening their cyclic structure.2. The process of detoxification corresponds to physiological state of larvae from early symptoms of paralysis to complete recovery within several hours.     

Biosynthesis and degradation of juvenile hormone in corpora allata and imaginal wing discs of Galleria mellonella (L.)

The rate of juvenile hormone (JH) biosynthesis by corpora allata-corpora cardiaca complex (CA/CC) during two last larval instars of Galleria mellonella was analysed. The rate of biosynthesis reaches maxima at the beginning of the VIth and VIIth instars. It is markedly reduced before the last larval ecdysis and after the first day of the last larval instar. After passing the second day of the last larval instar CA/CC exhibits again an increased ability for the biosynthesis of JH.The JH esterase activity in CA/CC is very low at the beginning of last larval instar and rapidly increases after the first day of this instar. Beginning on the second day of last larval instar the rate of JH hydrolysis is always higher than the rate of JH synthesis in CA/CC. It is concluded that the secretion of JH by CA/CC is possible until the second day of the last larval instar. After this, JH-acid can be supplied by CA/CC to peripheral tissues.The imaginal wing discs of mobile prepupa exhibit the ability to methylate JH-acid. It is concluded that some elevations of JH titre in G. mellonella haemolymph after the second day of VIIth instar are due in part to JH-acid methyltransferase activity in the imaginal discs.     

Ultrastructure of the prothoracic gland cells of the last instar of Galleria mellonella in relation to the state of development

The prothoracic glands of the last instar of Galleria mellonella undergo characteristic alterations of their cellular fine structure closely related to cellular activity. During progressive secretory activity of the gland cells there are extensive plasmalemmal infoldings and formation of a pronounced lacunar system. Mitochondria of the active cell phase are characterized by a specific increase in size and paler colour of the matrix. In contrast to the alterations, nuclei, ER and Golgi cisterns do not undergo any submicroscopic changes during the different phases of cellular activity. The relationship between the substructural phenomena and the specific phases of cellular activity are discussed.     

The synthesis of RNA and silk protein in Galleria mellonella silk glands

The silk protein synthesis in silk glands of Galleria mellonella is preceded by the increase of total RNA content. The levels of the main RNA classes: 28S and 18S rRNA, tRNA as well as poly(A) + RNA change proportionally to the total RNA pool of glands. The fibroin-like silk protein of molecular weight of about 240 000 is characterized by the high content of four amino acids: glycine, alanine, serine and leucine, which account for more than 70% of amino acid residues. This fibroin-like protein is present in the posterior, middle and anterior parts of silk gland of the last instar larvae.     

Correlations between juvenile hormone esterase activity,ecdysone titre and cellular reprogramming in Galleria mellonella

Juvenile hormone esterase (JHE) activity, ecdysone titre, and developmental competence of the epidermis were determined in last instar larvae and pupae of Galleria mellonella. Haemolymph JHE activity reaches a peak before increases are observed in ecdysone titre both during larval-pupal and pupal-adult metamorphosis. JHE activity is low during the penultimate larval instar although general esterase activity is relatively high. In last instar larvae two ecdysone peaks are noted after the increase in JHE activity. Furthermore, epidermal cell reprogramming occurs just after the increase in haemolymph JHE activity and possibly before the first increase in ecdysone titre. This was tested by injection of high doses of β-ecdysone into last instar larvae of different ages resulting in rapid cuticle deposition. Reprogramming occurred if the resulting cuticle was of the pupal type. These correlative observations may increase our understanding of the relative importance of an ecdysone surge in the absence of JH in reprogramming of the insect epidermis.     

大蜡螟的性选择行为

【目的】针对大蜡螟Galleria mellonella L.的性选择行为进行系统观察分析,为大蜡螟性信息素全组分的结构鉴定及利用信息素行为调控技术防控该虫提供依据。【方法】分别对不同体重、不同日龄和不同交配经历的大蜡螟成虫进行标记,在红光灯下观察并记录大蜡螟雌雄虫的性选择行为。【结果】在（26±0.5）℃、相对湿度60%、全黑暗条件下,无论雌虫还是雄虫,均倾向于选择与之体重相接近的异性个体进行交配。雌雄成虫均偏向于选择3日龄的异性个体进行交配;雌虫对不同日龄雄虫的选择率大小顺序为3日龄> 5日龄> 1日龄,而雄虫对不同日龄雌虫的选择率大小顺序为3日龄>1日龄> 5日龄。交配经历影响大蜡螟的性选择行为,雌虫优先选择已交配的雄虫进行交配,选择率为74.6%;雄虫也优先选择已交配的雌虫进行交配,选择率为79.4%。【结论】雌雄虫体重、日龄和交配经历能不同程度的影响大蜡螟的性选择行为,这为进一步研究雌雄交配信号奠定基础。