Browsing by Subject "kallus"

Chicory (Cichorium intybus) is a biennial or perennial plant belonging to Asteraceae family grown worldwide for its roots, but also for its leaves. Chicory has been utilized as a food crop, but also because of its medicinal properties, for at least two millennia. The aim of the Master's thesis was to produce hair root and cell cultures from chicory, and to evaluate the antimicrobial and antioxidant properties of extracts made from them. Hair root infection is caused by the soil-borne bacterium Agrobacterium rhizogenes, which transfers its own DNA into the genome of the plant and causes the plant to produce opines which the bacteria uses as a nutrient source. Hairy root infection causes the plants to grow excessive amount of lateral roots and at the same time increases the formation of secondary metabolites. Hairy roots can be grown on a solid or liquid medium without added plant hormones, and this phenomenon is utilized in a number of biotechnological applications. The successful initiation of hair roots requires suitable conditions and components, but once these are clear the process itself is quite simple. Wounded explants are infected with either a liquid bacterial suspension or by direct transfer of bacterial growth. After infection bacterial growth is eliminated with the use of antibiotics. Hairy roots are initially identified by morphological traits and verified by detecting rol genes with the use of PRC. Plant cell suspension cultures are produced from explants with the help of auxin and cytokinin in suitable proportions. As with hairy root cultures, plant cell suspension cultures can be harnessed to produce various molecules of economic benefit. Bioactivity of plant extracts can be studied by a variety of different methods. DPPH and antimicrobial assays were used to investigate the bioactivity of hairy root and cell suspension cultures produced for the study. The DPPH assay is used to measure radical scavenging properties of samples, by comparing the results to a reference antioxidant such as for example Trolox, which is a synthetic vitamin-E. Methanol extracts of hairy roots, cell suspension cultures, and natural roots were assayed for their antioxidant properties with the DPPH assay. Hot water extracts of hairy root and cell suspension cultures were tested against VTT-E70045 Staphylococcus aureus strain for antimicrobial properties. The results of the study showed that especially the antioxidant properties of chicory hair roots differ greatly from natural roots and cell suspension cultures. The radical scavenging properties of hairy root extracts were up to 45 times more potent than of extracts made from natural root and cell suspension cultures. The results of the antimicrobial experiment showed that all extracts from hair root and cell suspension cultures had bacteriostatic properties. One hairy root clone 2R5 clearly had antimicrobial effects, and it would be interesting to do a more thorough assessment to find out which compounds are responsible for this.