乳糖操纵子的直接诱导剂是（    ）

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SQL Error: select id,body,options from ***_enewstiku where sourceid='27515' and id < 2271452 and id<>'2271452' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='27515' and id > 2271452 and id<>'2271452' order by id asc limit 5