Inosine also triggered germination in binary combinations with L-serine, L-methionine, and L-histidine, albeit at lower rates. Interestingly, even though L-serine shows negative coop- erativity, the germination rate for inosine supplemented with L-serine was 80% of the germination rates obtained for spores treated with all six cogerminants. Spores treated with mixtures of inosine–L-methionine and inosine–L-histidine showed re- duced germination rates compared with those of spores treated with inosine–L-alanine. However, a ternary mixture of inosine– L-methionine–L-histidine doubled spores’ germination rates compared to those of spores treated with either inosine–L- methionine or inosine–L-histidine. Interestingly, addition of L-methionine (but not L-histidine) reduced the germination rate of spores treated with inosine–L-serine and inosine–L- valine but not with inosine–L-alanine. Addition of L-histidine to the inosine–L-methionine–L-serine mixture restored spores’ germination rates to values comparable to those of spores germinated with inosine–L-serine mixtures. In contrast, addi- tion of L-histidine did not increase germination rates of spores treated with inosine–L-valine–L-methionine (Fig. 4).