Vilches Silvia, Canals Rocío, Wilhelms Markus, Saló Maria Teresa, Knirel Yuriy A, Vinogradov Evgeny, Merino Susana, Tomás Juan M
Departamento de Microbiología, Facultad de Biología, Universidad de Barcelona, Diagonal 645, 08071 Barcelona, Spain.
N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119991, Russia.
Microbiology (Reading). 2007 Aug;153(Pt 8):2393-2404. doi: 10.1099/mic.0.2007/006437-0.
A mutation in galU that causes the lack of O34-antigen lipopolysaccharide (LPS) in Aeromonas hydrophila strain AH-3 was identified. It was proved that A. hydrophila GalU is a UDP-glucose pyrophosphorylase responsible for synthesis of UDP-glucose from glucose 1-phosphate and UTP. The galU mutant from this strain showed two types of LPS structures, represented by two bands on LPS gels. The first one (slow-migrating band in gels) corresponds to a rough strain having the complete core, with two significant differences: it lacks the terminal galactose residue from the LPS-core and 4-amino-4-deoxyarabinose residues from phosphate groups in lipid A. The second one (fast-migrating band in gels) corresponds to a deeply truncated structure with the LPS-core restricted to one 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) and three l-glycero-d-manno-heptose residues. galU mutants in several motile mesophilic Aeromonas strains from serotypes O1, O2, O11, O18, O21 and O44 were also devoid of the O-antigen LPS. The galU mutation reduced to less than 1 % the survival of these Aeromonas strains in serum, decreased the ability of these strains to adhere and reduced by 1.5 or 2 log units the virulence of Aeromonas serotype O34 strains in a septicaemia model in either fish or mice. All the changes observed in the galU mutants were rescued by the introduction of the corresponding single wild-type gene.
已鉴定出嗜水气单胞菌AH-3菌株中galU基因的一个突变，该突变导致缺乏O34抗原脂多糖（LPS）。事实证明，嗜水气单胞菌GalU是一种UDP-葡萄糖焦磷酸化酶，负责从1-磷酸葡萄糖和UTP合成UDP-葡萄糖。该菌株的galU突变体表现出两种LPS结构类型，在LPS凝胶上表现为两条带。第一条带（凝胶中迁移较慢的带）对应于具有完整核心的粗糙菌株，但有两个显著差异：它缺乏LPS核心末端的半乳糖残基以及脂多糖A中磷酸基团上的4-氨基-4-脱氧阿拉伯糖残基。第二条带（凝胶中迁移较快的带）对应于一种深度截短的结构，其LPS核心仅限于一个3-脱氧-D-甘露糖-辛-2-酮酸（Kdo）和三个L-甘油-D-甘露庚糖残基。来自血清型O1、O2、O11、O18、O21和O44的几种运动性嗜温气单胞菌菌株中的galU突变体也缺乏O抗原LPS。galU突变使这些气单胞菌菌株在血清中的存活率降低至不到1%，降低了这些菌株的黏附能力，并使气单胞菌血清型O34菌株在鱼类或小鼠败血症模型中的毒力降低了1.5或2个对数单位。通过引入相应的单一野生型基因，挽救了在galU突变体中观察到的所有变化。
