Correlation between constitutive heterochromatin and restriction enzyme resistant chromatin in Arcyptera tornosi (Orthoptera).

Fixed mitotic chromosomes of A. tornosi have been analysed by means of C-banding, DA-DAPI and Chromomicin A3 fluorescence, as well as by digestion in situ with Alu I, Hae III, Hinf I and Hind III restriction endonucleases. From the results obtained at least nine types of chromatin can be distinguished in A.

Spectroscopic study of N-nitroso compounds decomposition in presence of DNA bases.

Decomposition kinetics of N-ethyl-N-nitrosourea (ENU) as well as that of N-methyl-N-nitroso-N'-nitroguanidine (MNNG) in water medium was studied by means of differential UV spectroscopy. Rate constants of the first order reaction were evaluated. The influence of DNA bases on decomposition rate of above-mentioned compounds was also estimated.

Analysis and comparison of two methods to detect hepatitis B antigen. Counterelectrophoresis (CEP) and reversed passive latex-agglutination (RPLA) technic in relationship to radioimmunoassay.

The authors evaluated two methods for detection of hepatitis B surface antigen, reversed passive latex agglutination and counterelectrophoresis, using radioimmunoassay as a control. The RPLA test (Antigen I, Pfizer Inc., Lot no.