[en] Vinblastine is shown to induce pronuclear fusion failure in conjugating Tetrahymena thermophila. In this alternate conjugational pathway gametic pronuclei are exchanged between conjugants but do not fuse. Each pronucleus undergoes one mitotic division to produce a new macro- and micronucleus. Genetic consequences of pronuclear fusion failure include the following: (1) the progeny are whole genome homozygotes with nuclei derived from single meiotic products, and (2) half of the progeny are heterokaryons with micro- and macronuclei of different genetic origins. These facts make this process extremely useful in strain construction and mutant isolation. The induction of pronuclear fusion failure by vinblastine suggests that microtubules play an essential role in pronuclear fusion. In this paper the authors present autoradiographic and genetic evidence that vinblastine induces pronuclear fusion failure in T. thermophila

[en] Instrumental neutron activation analysis (INAA) methods have been developed for the simultaneous determination of multielement concentrations in both particulate and soluble fractions of atmospheric wet precipitation (AWP). Samples of AWP collected across Canada by Canadian Network for Sampling Precipitation (CANSAP) have been analyzed. The INAA method involves for sequential irradiations and counting after five different decay periods for measuring Ag, Al, As, Au, Ba, Br, Ca, Ce, Cl, Co, Cr, Cu, Dy, Fe, Hf, Hg, I, K, La, Mg, Mn, Na, Rb, Sb, Sc, Se, Sm, Sr, Ti, V and Zn. Precision and accuracy of the INAA methods have been evaluated, and detection limits have been calculated. (author)