An Aum Shinrikyo biologist testified at cult founder Shoko Asahara's trial Thursday that he did not think much about the sarin produced at an Aum facility when he was first shown a sample.

Taking the stand for Asahara's defense team at the Tokyo District Court, Seiichi Endo, 38, said he was shown the sample in a triangular flask in November 1993 by cult chemist Masami Tsuchiya.

Endo said this occurred in a visit to Tsuchiya's lab at the Aum complex in Kamikuishiki, Yamanashi Prefecture. He said he merely thought the substance was a poison gas.

The biologist, charged with taking part in the deadly June 1994 sarin attack in Matsumoto, Nagano Prefecture, claimed he heard from senior cultist Tomomasa Nakagawa in February 1993 that Aum had been attacked with gas.

Endo said he saw the sarin after Nakagawa told him this. Endo said he was aware the chemicals to produce sarin were bought via a dummy firm that specialized in buying chemical reagents.

He also purchased reagents from the firm but mainly for his genetic engineering work. Those bought by Tsuchiya had nothing to do with him, Endo claimed.

Endo said he does not deny media reports that genetic engineering experiments carried out at his lab were part of studies on Asahara's DNA.

The defense team later questioned Endo on the cult's attempted attack on the residence of Daisaku Ikeda, leader of the nation's largest lay Buddhist organization, Soka Gakkai. Asahara allegedly considered the group Aum's enemy.

Endo refused to testify on the details of the failed sarin gassing attempt in 1993 in Tokyo's Hachioji. Although Endo did not have a medical license, the late Hideo Murai -- Aum's top scientist -- told him to take part as a member of Aum's medical team.

Endo said he did whatever he was told to do, as he thought complying with orders was a part of his training.