Afaf Baktir

Potensi Enzim Dekstranase dari Arthrobacter sp. Galur B7 sebagai Penghambat Plak Gigi

Dextranase of Arthrobacter sp. strain B7 (B7DEX enzyme) was characterized in this study. This enzyme hydrolyzed sucrose and dextran, but not other glucans (starch, nigeran, cellulose, β-soluble glucan). It also hydrolyzed glucan from dental plaque with the activity of 7.38 ± 0.66 U/ml, where the activity toward dextran was 31.88 ± 1.24 U/ml. The enzyme exhibited the pH optimum of 7 and the temperature optimum of 50 °C. Its optimum stability was at pH 7 and 50 °C. The enzyme was inhibited by Fe3+, Cu2+, Zn2+, and Ag+, but not by the anionic detergent (SDS) and the nonionic detergent (Triton-X). The enzyme was activated by Ca2+, Na+, Mg2+, and saliva.

The Potency of Dextranase from Arthrobacter sp. Strain B7 as Dental Plaque Removal

A number of abiotic stress responsive genes have been identified from various plant species through reverse genetic strategy. A group of genes are involved in plant responses to stress; they are activated by diverse stress conditions and through different mechanisms. One single gene can be induced by several different stress factors; on the other hand, a number of genes can be up-regulated by a single factor. In Physcomitrella patens, through Northern hybridization, the transcript level of the gene GFDD4-I was detected to be markedly increased by ABA, dehydration and cold, but not by salinity and osmotic stress. In Arabidopsis thaliana, a homologous gene to GFDD4-1 namely At2g47770, was confirmed to fulfill similar function as in P. patens: it is inducible by various abiotic stress treatments, i.e. ABA, dehydration, salinity, and cold. Inducible genes in response to abiotic stress factors may be responsible for plant tolerance to those factors.