Insecticidal and fungicidal activity of new synthesized chitosan derivatives

Chitosan, the N-deacetylated derivative of chitin, is a potential biopolysaccharide owing to its specific structure and properties. In this paper, we report on the synthesis of 24 new chitosan derivatives, N-alkyl chitosans (NAC) and N-benzyl chitosans (NBC), that are soluble in dilute aqueous acetic acid. The different derivatives were synthesized by reductive amination and analyzed by 1H NMR spectroscopy. A high degree of substitution (DS) was obtained with N-(butyl)chitosan (DS 0.36) at a 1:1 mole ratio for NAC derivatives and N-(2,4-dichlorobenzyl)chitosan (DS 0.52) for NBC derivatives. Their insecticidal and fungicidal activities were tested against larvae of the cotton leafworm Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae), the grey mould Botrytis cinerea Pers (Leotiales: Sclerotiniaceae) and the rice leaf blast Pyricularia grisea Cavara (Teleomorph: Magnaporthe grisea (Hebert) Barr). The oral feeding bioassay indicated that all the derivatives had significant insecticidal activity at 5 g kg(-1) in artificial diet. The most active was N-(2-chloro-6-fluorobenzyl)chitosan, which caused 100% mortality at 0.625 g kg(-1), with an estimated LC50 of 0.32 g kg(-1). Treated larvae ceased feeding after 2-3 days; the mechanism of action remains unknown. In a radial hyphal growth bioassay with both plant pathogens, all derivatives showed a higher fungicidal action than chitosan. N-Dodecylchitosan, N-(p-isopropylbenzyl)chitosan and N-(2,6-dichlorobenzyl)chitosan were the most active against B cinerea, with EC50 values of 0.57, 0.57 and 0.52 g litre(-1), respectively. Against P grisea, N-(m-nitrobenzyl)chitosan was the most active, with 77% inhibition at 5 g litre(-1). The effect of different substitutions is discussed in relation to insecticidal and fungicidal activity.     

Changes of some metabolic parameters of the liver in chickens under the influence of Entomoxan]

From the 3rd week of life Studler-Cornish-breed chickens received a food mixed with Entomoxan (15 ppm HCH-gamma-Isomer in the food) for an 8 weeks period. 2,4,6, and 8 weeks after the beginning of the experiment livers of the chickens were examined for RNA-, DNA-, total protein- and total aminonitrogen contents. The RNA-values decrease constantly where as those of DNA increase up to the 4th week and after that decline. Total protein contents rise up to the 4th week. After 2 and 8 weeks the contents of amino-nitrogen are lower in experimental birds than in controls.     

Quantitative Untersuchungen über die Nahrungsaufnahme der SchneckeHelix aperta Born

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Anwendung der Antibiotika im Pflanzenschutz,unter besonderer Berucksichtigung ihrer Aufnahme,Weiterleitung und ihres Verbleibs in der höheren Pflanze

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