Dytiscus

Marginalin [96] 18 (Scheme 3), a yellow pigment from pygidial glands of Dytiscus marginalise was found to fix solidly on a variety of supports. When... 

Water beetle (Dytiscus) defence bombardier beetle (Bradynus) peroxidase substrate for ultimate benzoquinone discharge... 

The secretion of large amounts of cortexone (36) by the water beetle (Dytiscus maaginalis) as a defensive substance has been reported ... 

CisH,o04, Mr 254.24, yellow cryst., mp. 245.5 -247 C, occurs in the defence secretion of the water beetle Dytiscus marginalis. 

Trendelenburg, M. F., Zentgraf, H Franke, W. W., and Gurdon, J. B. (1978). Transcription patterns of amplified Dytiscus genes coding for ribosomal RNA after injection into Xenopus oocyte nuclei. Proc. Natl Acad. Scl U.S.A. 75, 3791-3795. 

R. arvalis Dytiscus larvae Morphology / Growth Lardner(l998)... 

R. dalmatina /R. temporaria/ R. arvalis / H. arborea Dytiscus larvae Mcnphology / Life history Lardner (2000)... 

Repeated rDNA has also been shown in the cricket, Acheta (Lima-de-Faria et al., 1969), the water beetles, Dytiscus and Colymbetes (Gall, et al., 1969), and the fungus... 

As early as 1901, Ciardina described the presence of a specially stainable chromatin body in oogonia and oocytes of the water beetle Dytiscus, later on to become known as the Giardinas body. About 30 years later, Bauer (1933) proved by the use of the Feulgen reaction that the Giardina s body contains a large amount of DNA. The occurrence of the extrachromosornal DNA is now well established for many insect species (see Table II). 

Benzoic acid derivatives Benzoic acid, p-hydroxybenzoic acid, protocatechuic acid methyl and ethyl esters, hydroquinone (D 22.2.5) Hydroquinone (D 22.2.5), H2O2 Secreted from the pygidial glands of the water beetles Dytiscus sp., feeding deterrent, antiseptic Synthesized in glands of the bombardier beetles Brachynus sp. (Fig. 338)... 

In many cases, these nurse cells have polyploid nuclei and synthesize large amounts of RNA s. In oocytes with metabolically inactive nuclei, the amplification of rDNA does not occur and rRNA are synthesized by trophic cells (Bier, 1965, 1967). In some beetles, for instance Dytiscus marginalis, active RNA synthesis is going on in trophic cells as well as in oocytes. Oocytes contain extrachromosomal DNA that is represented by Djiardine bodies (Bier et al., 1967). 

The water beetles of the Dytiscidae family convert dietary sterols e.g. cholesterol, see Chapter 7) to mammalian hormones like oestrone and testosterone, but most interesting is the cortisone-type cortexone (Figure 7.10). A Dytiscus beetle can contain as much as 1 to 3 mg of cortexone, which it can discharge from glands if attacked by a predator. 

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