Farhana Aisha, Khan Yusuf S.
College of Applied Medical Sciences, Jouf University, Saudi Arabia
Department of Anatomy, College of Medicine, University of Hail, Saudi Arabia.
Lipopolysaccharides (LPS) are important outer membrane components of gram-negative bacteria. They are large amphipathic glycoconjugates that typically consist of a lipid domain (hydrophobic) attached to a core oligosaccharide and a distal polysaccharide. These molecules are also known as lipoglycans due to the presence of lipid and sugar molecules. The lipopolysaccharides are composed of: 1. Lipid A: the hydrophobic domain, which is an endotoxin and the main virulence factor. 2. O-antigen, the repeating hydrophilic distal oligosaccharide. 3. The hydrophilic core polysaccharide. The lipid A component varies from one organism to another and is essential in imparting specific pathogenic attributes to the bacteria. Inherent to gram-negative bacteria, LPS provides integrity to the bacterial cell and a mechanism of interaction of the bacteria to other surfaces. Most bacterial LPS molecules are thermostable and generate a robust pro-inflammatory stimulus for the immune system in mammals. Since different types of LPS are present in different genera of gram-negative bacteria, LPS is used for serotyping gram-negative bacteria. More specifically, the O-antigen imparts serological distinction to the bacterial species. Also, the size and composition of LPS are highly dynamic among bacterial species. Due to its unique properties, LPS has gained considerable research focus to understand its complex structure, biogenesis, transport, and assembly. Besides, LPS is also a recognized biomarker due to its central role in host-pathogen interaction that facilitates the infection process.
脂多糖（LPS）是革兰氏阴性菌重要的外膜成分。它们是大型两性糖缀合物，通常由连接到核心寡糖和远端多糖的脂质结构域（疏水）组成。由于存在脂质和糖分子，这些分子也被称为脂聚糖。脂多糖由以下部分组成：1. 脂质A：疏水结构域，是一种内毒素和主要毒力因子。2. O抗原，重复的亲水性远端寡糖。3. 亲水性核心多糖。脂质A成分因生物体而异，对于赋予细菌特定的致病特性至关重要。作为革兰氏阴性菌所固有，LPS为细菌细胞提供完整性，并作为细菌与其他表面相互作用的一种机制。大多数细菌LPS分子具有热稳定性，并对哺乳动物免疫系统产生强烈的促炎刺激。由于不同类型的LPS存在于革兰氏阴性菌的不同属中，LPS被用于革兰氏阴性菌的血清分型。更具体地说，O抗原赋予细菌物种血清学差异。此外，LPS的大小和组成在细菌物种之间高度动态变化。由于其独特的性质，LPS在理解其复杂结构、生物合成、运输和组装方面受到了相当多的研究关注。此外，由于LPS在促进感染过程的宿主 - 病原体相互作用中起核心作用，它也是一种公认的生物标志物。
