Characterization of drowning by diatom test.

Examination by the diatom test, of different organs of corpses of individuals who died of drowning revealed the presence of frustules in all the visceral organs. Diatom load of different organs was found to be positively related with breadth/diameter of the frustule. Relatively larger diatoms were encountered in the lungs, heart and kidneys as compared to the other organs. Smaller diatoms up to 10 mu diameter were found in the brain, and bone marrow samples. However, diatoms were also recovered from the lungs, heart and kidneys of corpses of individuals in whom the cause of death was not drowning. Brain and bone marrow were considered reliable samples for executing the diatom test.

Inhibition of cytokinesis by lead (Pb2+) in a centric diatom.

Effect of inorganic and organo lead has been studied on the mitosis of a centric diatom Cyclotella meneghiniana f. unipunctata. Binucleate cells were formed in the presence of different concentrations of Pb2+ (1.0, 2.0, 3.0 and 5.0 mM) due to inhibition of cell plate formation. Lead at 5.0 mM concentration was more inhibitory than the other concentrations. Organo lead was a powerful depressant of cytokinesis than inorganic lead. Failure of cytokinesis might be due to disruption of microtubules. Formation of distinct nuclei delayed post incubation cell divisions suggest partial damage of mitotic spindles.