DDT induced ethological changes in estuarine fish

Synopsis Experiments were carried out to study the feeding rates of the predator fish Therapon jarbua (Forsk) on mullet juveniles, before and after treatment with DDT. Mullet juveniles treated with a subacute concentration, were refused by the control predators, whereas predators treated with a subacute concentration consumed more mullet juveniles. In the present study crescent perch T. jarbua were exposed to subacute and acute concentrations of DDT, and their behaviour was compared with that of the control predators. There were changes in oriented behaviour and co-ordinated movements, and in feeding, aggression and comfort behaviour of the fish. Inflammation in the gills, and caudal fin serration, were noticed in treated fishes. The findings presented here throw light on fundamental pathways by which pollutants interact with the behaviour of fishes.     

Novel non-glycerol-based cytofectins with lactic acid-derived head groups.

We report herein the design, synthesis, and transfection biology of a novel series of non-glycerol-based cationic lipids with lactic acid-derived head groups The synthetic procedure adopted herein for preparing 1-hydroxy-prop-2-yl head-group-based monocationic transfection lipids 1-7 is fairly straightforward and potentially applicable in designing other cationic lipids with lactic acid-derived head groups. A striking anchor-length dependency was observed in NIH3T3 cells in the sense that except lipid 4, all the other lipids were essentially transfection-inefficient. Ethidium bromide assay for the lipid:DNA interactions is consistent with the general observation that significant lipid:DNA interactions do not guarantee on improved transfection efficiency cationic lipid mediated gene delivery. Given its remarkable transfection properties and low cellular toxicity, lipid 4 is likely to find future use in the area of liposomal gene delivery.     

Does heterochromatin variation potentiate speciation? A study in Nesokia

An increasing incidence of sex-chromosome variation in constitutive heterochromatin, including individuals with mosaic genotypes, has been observed in a single natural population of Nesokia indica, the Indian mole rat. Variations in the heterochromatic areas of the X chromosome are largely due to deletions at R-band-positive regions corresponding to folate-sensitive fragile sites. All individuals with either a pre- or post-zygotic loss or gain of sex-chromosome heterochromatin have so far proved to be infertile. Whether such F1 sterility is due to abnormal gonadal development, gametic incompetence, or other factors is not clear. More important is the indication that the constitutive heterochromatin of this species may contain coding DNA sequences with putative regulatory functions.