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'Ecdysteroids' in keywords Facet   section ZfN Section C:Volume 038  [X]
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1983 (1)
1Author    Franz Römer, Ilona EisenbeisRequires cookie*
 Title    DNA Content and Synthesis in Several Tissues and Variation of Moulting Hormone-Level in Gryllus bimaculatus DEG (Ensifera, Insecta)  
 Abstract    The mode of growth o f several tissues in Gryllus bimaculatus was investigated during postembryonic development by cytophotometric methods. In contrast to the situation in holo-metabolous insects, the tissues growing by endomitosis reach only moderate levels of polyploidy. In this case the growth o f tissues is achieved by mitotic divisions o f small cells with subsequent polyploidization. The time courses of D NA synthesis were measured within the 3rd and, for comparison, the 8th larval instar by incorporation o f labelled thymidine followed by autoradiography. Hemocytes, cells of the regeneration crypts of the midgut, gonads and nervous tissue showed a continuous incorporation rate; by contrast, DNA synthesis in other tissues was confined to a given time within the moulting cycle. The changes in moulting hormone titre o f the 3rd larval instar were investigated. The quantities of ecdysone and 20-C)H-ecdysone were estimated by radioimmunoassay, and the hormones were identified by high pressure liquid chromatography (HPLC). The titre changes in time with at least 2 distinct maxima. The DNA synthesis periods are correlated with the hormone peaks, that o f epidermis and tracheae with the first peak, and that of pylorus, ileum, rectum, Malpighian tubules and fat body with the second. DNA synthesis in prothoracic glands and oenocytes exhibits a time course that is the inverse of the hormone-secretion time course. The question whether moulting hormones have an influence on D NA synthesis is discussed. 
  Reference    Z. Naturforsch. 38c, 112 (1983); received June 28/September 16 1982 
  Published    1983 
  Keywords    Polyploidy Levels, DNA Synthesis Development, Ecdysteroids, Gryllus bimaculatus 
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 TEI-XML for    default:Reihe_C/38/ZNC-1983-38c-0112.pdf 
 Identifier    ZNC-1983-38c-0112 
 Volume    38