Morii Hideaki, Hayashi Nobutaka, Uramoto Kiyoko
Faculty of Fisheries, Nagasaki University, Bunkyou, Nagasaki 852-8521, Japan.
Dis Aquat Organ. 2003 Feb 13;53(2):107-13. doi: 10.3354/dao053107.
Transferable resistance to various drugs was investigated in Photobacterium damselae subsp. piscicida from Japan. Drug resistances were transferred via plasmids of 100, 50, and 40 kb. Resistance to chloramphenicol (Cmr) was transferred on plasmids of all 3 sizes. The Cmr gene (cat) was cloned from the 50 kb plasmids pPDP8511 and pPDP9106 transferred from P. damselae subsp. piscicida strains isolated in different years and places in Japan. Subcloning localized the cat to within 1.5 kb HindIII-HincII (or PstI) fragments. Nucleotide sequences of the coding and flanking region of the cat were determined as 1607 bp (HindIII-HincII fragment) in pPDP8511 and 1568 bp (HindIII-PstI fragment) in pPDP9106, which corresponded with the sequence from nucleotides 40 to 1607 in pPDP8511. The nucleotide sequences identified an open reading frame (ORF) encoding 213 amino acid residues with a calculated molecular mass of about 24.8 kDa, a size consistent with the molecular mass of known cat gene products, and the ORF had maximum homology (99.5%) with a Type II CAT variant from Haemophilus influenzae.
对来自日本的美人鱼发光杆菌杀鱼亚种中各种药物的可转移抗性进行了研究。药物抗性通过100 kb、50 kb和40 kb的质粒进行转移。对氯霉素（Cmr）的抗性在所有这3种大小的质粒上均可转移。Cmr基因（cat）是从分别于不同年份和地点从日本分离的美人鱼发光杆菌杀鱼亚种菌株转移而来的50 kb质粒pPDP8511和pPDP9106中克隆得到的。亚克隆将cat定位在1.5 kb的HindIII - HincII（或PstI）片段内。在pPDP8511中cat编码区及其侧翼区域的核苷酸序列测定为1607 bp（HindIII - HincII片段），在pPDP9106中为1568 bp（HindIII - PstI片段），这与pPDP8511中核苷酸40至1607的序列相对应。该核苷酸序列鉴定出一个开放阅读框（ORF），编码213个氨基酸残基，计算所得分子量约为24.8 kDa，该大小与已知cat基因产物的分子量一致，并且该ORF与来自流感嗜血杆菌的II型CAT变体具有最高同源性（99.5%）。
