Abbau und Toxizität von Hexachlorbicyclo [2.2.1]-hept-5-en- Derivaten (Cyclodien-Insektizide) / Structural Aspects of Biological Conversion and Toxicity of Hexachloro-norbornene Derivatives (Cyclodiene-Insecticides)

1973 ◽  
Vol 28 (3-4) ◽  
pp. 107-112 ◽  
Author(s):  
W. Rückert ◽  
K. Ballschmiter

The aspects of molecular-structure and biological conversion have been studied for 12 derivatives of the endosulfan ether 1 [4, 5, 6, 7, 8, 8- hexachloro- 1, 3, 3a, 4, 7, 7a- hexahydro- 4, 7-methanoisobenzofuran]. Adults of a normal house-fly strain (Musca domestica) have been used in the assay. Derivatives of 1 monosubstituted in position I are found to be converted substantially faster than products disubstituted in position I and 3, respectively. Metabolism is inhibited for all compounds studied after application of piperonyl butoxide as a synergist. Besides proving that on oxidative metabolism has to be discussed and in fact could be proved for some derivatives, the intrinsic toxicity of the compounds studied shows up under these conditions. Some derivatives known to be metabolites of the pesticide Endosulfan® show a high intrinsic toxicity to houseflies if the oxidative metabolism is inhibited.

Author(s):  
Wah Chiu ◽  
David Grano

The periodic structure external to the outer membrane of Spirillum serpens VHA has been isolated by similar procedures to those used by Buckmire and Murray (1). From SDS gel electrophoresis, we have found that the isolated fragments contain several protein components, and that the crystalline structure is composed of a glycoprotein component with a molecular weight of ∽ 140,000 daltons (2). Under an electron microscopic examination, we have visualized the hexagonally-packed glycoprotein subunits, as well as the bilayer profile of the outer membrane. In this paper, we will discuss some structural aspects of the crystalline glycoproteins, based on computer-reconstructed images of the external cell wall fragments.The specimens were prepared for electron microscopy in two ways: negatively stained with 1% PTA, and maintained in a frozen-hydrated state (3). The micrographs were taken with a JEM-100B electron microscope with a field emission gun. The minimum exposure technique was essential for imaging the frozen- hydrated specimens.


2021 ◽  
pp. 110423
Author(s):  
Manuel Sánchez ◽  
Carolaynne Gómez ◽  
Constanza Avendaño ◽  
Iliak Harmsen ◽  
Daniela Ortiz ◽  
...  

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