Comparative karyological studies on [tilapia fish] oreochromis species

An attempt was made to study the karyological differences among three of Oreochromis species nominated Tilapia nilotica [O. niloticus], Tilapia aurea [O. aureus] and Tilapia galilae [O. galileus]. The diploid number of chromosomes were 22 pairs in all species, in which one was a large acrocentric pair for each species. The 22 pairs of chromosomes have nearly similar length and centromere location in all three species. This similarity in genetic make-up allows cross- breeding and hybrid vigor production among these three Oreochromis species and this is also responsible for similarity in feeding, breeding and biological behavior among them

Synthesis and biological activity of some new 2- [5-mercapto-1,3,4-oxadiazol-2-ylmethyl] -4-benzyl-1 [2H] -phthalazinone derivatives

Synthesis of some derivatives of 5-mercapto 3-[3-pyridyl] 1,2,4- triazole [IV] of certain biological activity was achieved by reacting nicotinic acid hydrazide [II] with different isothiocyanates and the resulting thiosemicarbazide [III] was cyclised to the required mercaptotriazole derivatives