Human intestinal absorption is estimated using a human colon carcinoma cell line (Caco-2) cells from human colorectal adenocarcinoma, intestinal perfusion, or a mammalian model. These current evaluation systems are limited in their ability to estimate human intestinal absorption. In addition, in vivo evaluation systems using laboratory animals such as mice and rats entail animal ethics problems, and it is difficult to screen compounds on a large scale at the drug discovery stage. Thus, we propose the use of Bombyx mori larvae for evaluation of intestinal absorption of compounds as an alternative system in this study.

Prof. Atsushi Toyoda and Prof. Asao Fujiyama (Center for Information Biology) contributed to sequencing midgut transcriptome of B. mori. Dr. Hidemasa Bono and Dr. Takeru Nakazato (Database Center for Life Science) contributed to this work in comparative analysis of Caco-2 cells, human and B.mori gut transcriptomes.

Figure: Evaluation of model systems for intestinal permeability and the internal structure of B.mori larva. Most of the body is occupied by the midgut (green), and its surroundings are filled with hemolymph(yellow).

A collaborative research project “The Ohanami project” was launched in 2015 by the organizers of the conference of high-throughput sequencing technologies, the NGS Field 4th meeting. The project aimed to collect environmental DNA (eDNA) from petal surfaces of flowering cherry Cerasus × yedoensis ‘Somei-yoshino’ to analyze the origins of eDNA found on the plants. Somei-yoshino is a cultivar widely cultivated across the Japanese archipelago, and the trees are all clones of a single tree since it is propagated through grafting and self-incompatible. Over 150 collaborators joined the sampling campaign of the project to collect eDNA samples from 577 locations (Fig. 1). The project team performed 16S rRNA amplicon sequencing method to analyze the origins of eDNA. As a result of DNA sequencing, we found that the DNA sequences of common plants including the one like Japanese Ceder are found on the petal surfaces along with the DNA of flowering cherry itself. This project is the first project that revealed the existence of eDNA on petal surfaces with many samples from a broad geographical range. The project also showed that a crowd-sourcing approach is applicable on DNA sampling from a wide range of locations in a short term.

Fig. 1: DNA sampling from petal surfaces of flowering cherry. Collaborators used the swab kit to collect environmental DNA from the petal surfaces.

New assistant professor joins NIG as of March 1, 2018.

Keiko TAKANAMI: Mouse Genomics Resource Laboratory (MGRL), Koide Group