利用化學方法誘導A. espejiana Bal-31 突變，從中篩選到澱粉.blksq.
突變菌株，S1c 及S2a，並探討突變株的澱粉.blksq.誘導性質 。野生型
菌株及S1c 突變株，在 Bal 及澱粉培養基中生長良好，而添加葡萄糖、
蔗糖或麥芽糖的培養基，則反而會抑制細菌的生長。唯有 S2a 突變株能
適應麥芽糖培養基。含澱粉之培養基可以有效地誘導野生型及 S1c 突變
株之澱粉.blksq.的分泌，且這種分泌誘導與細胞內澱粉.blksq.無關 。
但在Bal 培養基中，唯有 S1c突變株能夠分泌澱粉.blksq.。即使添加葡
萄糖亦不能完全抑制 S1c 澱粉.blksq.的釋出。因此，S1c的突變可能是
改變了基因的調控部份(regulatory element)。S2a 突變株雖在 Bal 或
澱粉的培養基中生長良好，但卻無澱粉.blksq.的分泌。然而在含麥芽糖
培養基中 6 小時之後，便大量分泌澱粉.blksq.，.blksq.活性在第12小
時便達到高峰，此高水平的.blksq.活性可穩定地維持相當長的時間。從
tetracycline 處理的結果，顯示 S2a 突變株所分泌的澱粉.blksq.穩定
性高。顯然 S2a 的突變可能相當複雜，不但改變了對誘導物的反應，也
可能改變.blksq.基因的 coding region 之核 .blksq. 酸部份序列，使
.blksq. 蛋白的穩定性改變。

Two mutants,S1c and S2a was isolated by treatment of Alteromonas
espejiana Bal-31 with ethyl methanesulfonate. Bal-31 and mutant
S1c grew well in the Bal and starch medium, but grew poorly in
the glucose, sucrose and maltose medium. Only mutant S2a adapted
very well in maltose medium. Extracellular α-amylase of Bal-31
and mutant S1c could be induced by the present of starch in
medium. The induction had no relation with intracellular α-amy-
lase activity. Mutant S1c was able to synthesize enzyme in Bal
medium. It exhibited incomplete repression of enzyme synthesis
by glucose. Mutation of S1c should affect on regulatory element.
Mutant S2a grew well in Bal and starch medium, but no enzyme
activity could be detected in the medium. When mutant S2a grew
in maltose medium, exoamylase activity was observed six hours
after culture.Maximum α-amylase accumulation was reached twelve
hours after culture and the high level of enzyme activity was
further maintained for at least sixteen hours. This high level
of activity was not affected by tetracycline treatment. Our
result indicates that the mutation of S2a mutant could be
complicated; it altered the response of cells to the inducer and
might also change the stability of enzyme molecules which could
be due to some modification in the coding region of gene.
Two mutants,S1c and S2a was isolated by treatment of Alteromonas