1. Wstęp. 2. Metody klasyczne stosowane do identyfikacji bakterii. 3. Metody molekularne stosowane do identyfikacji mikroorganizmów glebowych. 4. Analiza zawartości zasad G+C w DNA. 5. Hybrydyzacja kwasów nukleinowych. 6. Analiza sekwencji kwasów nukleinowych. 7. Podsumowanie

Abstract: Biodiversity and the identification of new important features of microorganisms is crucial for the development of biotechnology. The current knowledge about microbs in natural environments is limited, thus the analysis of the microbial diversity in nature is not an easy task. So far, only a small percentage of prokaryotic microorganisms has been identified. It is believed that the soil environment is one of the richest reservoirs of microorganisms, as approximately 2 000 to 18 000 prokaryotic genomes can be isolated from one gram of soil. In this publication the selected methods used to identify microorganisms are presented. The first molecular marker used in the genetic identification of soil microorganisms was the analysis of the G+C base content, sincemicroorganisms exhibit differences in the (G+C)/(A+T) relative factor. Another method used to identify bacteria is the nucleic acid hybridization. This technique involves a determination of the degree of similarity of DNA-DNA between two organisms. One of the most frequently used hybridization technique is FISH – fluorescent in situ hybridization. The most precise method for analyzing the nucleic acids is sequencing, i.e. determining the order of nucleotides which form the genetic information of the microorganism studied. Very often in molecular studies the 16S rDNA molecule is subjected to sequencing.

1. Introduction. 2. Classical methods used to identify bacteria. 3. Molecular methods used in the identification of soil microorganisms. 4. Analysis of the G+C DNA content. 5. Nucleic acid hybridization. 6. Analysis of nucleic acid sequences. 7. Summary