[Yeasts--the pathogen of weed diseases].

Plant pathogenic yeast were isolated from infected weeds that occur in cereal crops. On the basis of morphological, physiological and biochemical properties the yeast isolated from sow thistle and dandelion have been identified as Rhodosporidium diobovatum Newell & Hunter and Rhodotorula sp. In the experiment the yeast caused pathological process on the weeds, from which they are isolated, on other types of weeds, but also on wheat, oat and soybean.

[Selection of thermophilic lactose-fermenting yeast strains].

The screening and selection of lactose-fermenting yeasts among 97 collection yeast strains belonging to different taxonomic groups has been conducted to obtain ethanol from whey. The strains (n=18) (1 strain of K. lactis. 16 strains of K. marxianus and 1 strain of C. kefyr) fermented lactose at 48 degrees C and 15 selected strains rapidly consumed lactose within 24-48 h of cultivation. The presence of 6% of ethanol in the medium resulted in a considerable growth inhibition (more than 80%) of the selected strains.

[Mechanisms of bacteria resistance to heavy metals].

Bacteria have adapted to the presence of heavy metal ions in their habitats. There are five main mechanisms of heavy metal resistance in bacteria extracellular barrier, active transport of metal ions (efflux), extracellular sequestration, intracellular sequestration, reduction of metal ions. Genetic determinants of heavy metal resistance can be localized both on bacterial chromosomes and on extrachromosomal genetic elements. Horizontal gene transfer plays an important role in the spread of heavy metal resistance in nature. Interactions between bacteria and heavy metal ions are of great interest both as a fundamental process and potential bioremedial technology.