%0 Journal Article
%T Cell Envelope of Corynebacteria: Structure and Influence on Pathogenicity
%A Andreas Burkovski
%J ISRN Microbiology
%D 2013
%R 10.1155/2013/935736
%X To date the genus Corynebacterium comprises 88 species. More than half of these are connected to human and animal infections, with the most prominent member of the pathogenic species being Corynebacterium diphtheriae, which is also the type species of the genus. Corynebacterium species are characterized by a complex cell wall architecture: the plasma membrane of these bacteria is followed by a peptidoglycan layer, which itself is covalently linked to a polymer of arabinogalactan. Bound to this, an outer layer of mycolic acids is found which is functionally equivalent to the outer membrane of Gram-negative bacteria. As final layer, free polysaccharides, glycolipids, and proteins are found. The composition of the different substructures of the corynebacterial cell envelope and their influence on pathogenicity are discussed in this paper. 1. The Genus Corynebacterium The genus Corynebacterium belongs to the class of Actinobacteria (high G+C Gram-positive bacteria) and comprises a collection of morphologically similar, irregular- or club-shaped nonsporulating (mico)aerobic microorganisms [1, 2]. To date, 88 species were taxonomically classified [3]. More than half of these, that is, 53 species, are occasional or rare causes of infections, with the most prominent member of the pathogenic species being Corynebacterium diphtheriae, which is also the type species of the whole genus. Several pathogenic species are considered to be part of the human skin flora, for example, Corynebacterium amycolatum or Corynebacterium jeikeium, others are considered as zoonotic agents, for example, Corynebacterium pseudotuberculosis, Corynebacterium ulcerans, or Corynebacterium xerosis [3]. Biotechnologically important species used for the industrial production of nucleotides and amino acids are Corynebacterium ammoniagenes, Corynebacterium efficiens, and Corynebacterium glutamicum. C. glutamicum especially is dominating the field of white (bacterial) biotechnology with a production of two million tons of L-glutamate and 1.8 million tons of L-lysine per year [4] and an increasing application as platform organism for the industrial production of various metabolites [5]. Based on their medical importance as etiological agent of diphtheria and their enormous biotechnological potential, C. diphtheriae and C. glutamicum, respectively, have been the best investigated Corynebacterium species for many years. In fact, these were also the first species for which genome sequences became available [6¨C8]. With the development of high throughput sequencing techniques, to date numerous genome
%U http://www.hindawi.com/journals/isrn.microbiology/2013/935736/