Developmental Changes in the⁴⁵Ca²⁺ Uptake by <i>Trichoderma viride</i> Mycelium

The rate of the ⁴⁵Ca²⁺ uptake by the submerged Trichoderma viride mycelium increased with the age of the culture from 6 h until a maximum which was reached at about 30 h, and then decreased until the uptake was virtually zero. The decrease in the rate of the ⁴⁵Ca²⁺ uptake was accompanied by an increase of mycelial mass. The uptake rate could not be reactivated upon substituting the medium for a fresh one, without or with dilution of the mycelium. The results suggest that the rate of ⁴⁵Ca²⁺ uptake reflects the biological age of the submerged culture. The surface-cultivated mycelium took up ⁴⁵Ca²⁺ proportionally with time. The autoradiography of colonies showed that ⁴⁵Ca²⁺ was distributed homogeneously throughout the mycelium during vegetative growth while conidiation was accompanied by a massive accumulation of ⁴⁵Ca²⁺ in conidia

Ag(I) and Zn(II) isonicotinate complexes: Design, characterization, antimicrobial effect and CT–DNA binding studies

<div><p></p><p>Trinuclear Ag(I) (<b>1</b>) and dinuclear and mononuclear Zn(II) isonicotinate (<b>2</b> and <b>3</b>) complexes were prepared and characterized by X–ray crystallography, elemental analysis, IR spectroscopy and thermal analysis. Single crystal analysis of the Ag(I) complex reveals two different monodentate carboxylate coordination modes, protonated and deprotonated, respectively. IR spectra showed correlations between isonicotinate coordination modes and <i>Δ</i>(<i>ν</i>_as–<i>ν</i>_s)_IR values. In addition, the hydrogen bonds significantly influence a position of carboxylate absorption bands. Moreover, IC₅₀ and MIC data for bacteria, yeasts and filamentous fungi were determined and the binding of Ag(I) and Zn(II) complexes to calf thymus DNA was investigated using electronic absorption, fluorescence and CD measurements. Biological tests showed that the Ag(I) complex is more active than commercially used Ag(I) sulfadiazine against <i>E. Coli</i>. The fluorescence spectral results indicate that the complexes can bind to DNA through an intercalative mode. The Stern–Volmer quenching constants for investigated complexes obtained from the linear quenching plot are in the range of 1.67 × 10⁴ to 3.42 × 10⁴ M^–1.</p></div