Screening for Amyloid-β degradation activity on Metagenomic Libraries from Puerto Rico Soils

Diseases such as Parkinson and Alzheimer (AD) are related to the presence of protein aggregates (plaques) within the brain cells. These plaques are composed of the amyloid-β (Aβ40-42). An enzyme system that degrades the plaques will be needed in order to reduce the development of the disease. Metagenomics allows accessing, by culture independent approaches, activities of uncultivable microbes which represent 99% of the total microbes in soil. In our laboratory, novel enzymes activities like involved in antibiotic resistance, have been found in metagenomic libraries generated from forest soils. This fact leads us to propose if culture independent approaches allow the access of the majority of the microbial community in the environment, then, activities related by Aβ40 degradation could be present.  Four soil metagenomic libraries from two forests in Puerto Rico, dry and rainy forests, were used to screen the ability of using Aβ40 as the sole carbon source. The libraries were inoculated in Luria Bertani for 3 hrs, and after an OD600 of 0.2, the cells were washed and inoculated on minimal media (M-9) supplemented with Aβ40. After the incubation at 37°C, 132 clones from one rainy forest ML, and both MLs from the dry forest (215 clones total) showed growth in Aβ40. Some of the potential clones from the ML grew in 7 days, and showed differences in morphology (bigger colonies) from the control, which took 14 days to grow. The results suggest the presence of metabolic activity using amyloid-β, an important step to initiate studies in medical bioremediation.