Figure 1: The results of the Orthogonal Design Experiments L64(421) in LB broth. The results of conjugation obtained with the non-conjugative plasmid pCB182 were zero. This revealed that the uptake of naked DNA does not occur by transformation. Furthermore, the results of conjugations induced by bulk alumina were almost the same as the results when the nano-alumina concentrations were 0 mmol/L.