Insect pathogenic properties of Serratia marcescens: phage-resistant mutants with a decreased resistance to Cecropia immunity and a decreased virulence to Drosophila.
Insect pathogenic properties of Serratia marcescens: phage-resistant mutants with a decreased resistance to Cecropia immunity and a decreased virulence to Drosophila.
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粘质沙雷氏菌的昆虫致病特性：噬菌体抗性突变体，对天蚕免疫的抵抗力降低，对果蝇的毒力降低。
DOI：
10.1099/00221287-120-1-173
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发表时间：
1980
期刊：
影响因子：
--
通讯作者：
H. G. Boman
中科院分区：
文献类型：
--
作者：
C. Flyg;K. Kenne;H. G. Boman
从濒死的果蝇中分离到一株粘质沙雷氏菌（Serratia marcescens，Db 10）。从该菌株中分离到对链霉素（Db 11）和萘啶酸（Db 12）具有抗性的自发突变体。突变株Db 11可分离到两株能在Db 10、Db 11和Db 12上生长的芽孢杆菌，phi J和phi K，而不能在参比菌株上生长。marcescens。突变体Db 11被证明符合科赫假设。菌株Db 10及其抗虫衍生物无论是通过食物还是注射给药，对果蝇都是致死的。仅在7天培养物的无菌上清液中发现毒素的证据。这些提取物含有蛋白水解活性，并在免疫血淋巴中灭活抗菌活性。噬菌体phi J和phi K用于分离Db 11的噬菌体抗性突变体。三个这样的突变体和它们的亲本菌株进行了调查，他们的易感性从Cecropia免疫血淋巴。亲本菌株是耐温育与90%的血淋巴2小时，在37摄氏度;所有噬菌体抗性突变体是敏感的免疫血淋巴的“杀死时间”（即杀死90%的活细胞所需的时间）范围从15至55分钟。当相同的菌株进行比较，其毒力果蝇，噬菌体抗性突变体的毒力显着降低。由此可见，抗虫性在该菌的整体致病性中起着重要作用。marcescens。
A non-pigmented strain of Serratia marcescens (Db10) was isolated from moribund Drosophila flies. From this strain were isolated spontaneous mutants resistant to streptomycin (Db11) and nalidixic acid (Db12). Mutant Db11 was used for the isolation of two phages, phi J and phi K, which grew on Db10, Db11 and Db12, but not on three reference strains of S. marcescens. Mutant Db11 was demonstrated to fulfil koch's postulates. Strain Db10 and its antibiotic-resistant derivatives were lethal to Drosophila whether given in the food or by injection. Evidence for toxin(s) was found only in sterile supernatants from 7 d cultures. Such extracts contained proteolytic activity and inactivated the antibacterial activity in immune haemolymph from Cecropia. Phages phi J and phi K were used to isolate phage-resistant mutants of Db11. Three such mutants and their parental strain were investigated for their susceptibility to immune haemolymph from Cecropia. The parental strain was resistant to incubation with 90% haemolymph for 2 h at 37 degrees C; all phage-resistant mutants were susceptible to the immune haemolymph with "killing times" (i.e. the time required to kill 90% of the viable cells) ranging from 15 to 55 min. When the same strains were compared for their virulence to Drosophila, the phage-resistant mutants had significantly reduced virulence. It is concluded that resistance to insect immunity plays an important role in the overall pathogenicity of S. marcescens.