Cell Wall Rhamnan in Actinobacteria of the genus <i>Curtobacterium</i>
<b>Abstract</b>—Presence of the neutral glycopolymer rhamnan was established for members of the genus <i>Curtobacterium</i> (family <i>Microbacteriaceae</i>) using chemical and NMR spectroscopic methods. The rhamnan with the repeating unit, →2)-α-L-Rha<i>p</i>-(1 → 3)-α-L-Rha<i>p</i>-(1→, was found in <i>C. flaccumfaciens</i> pv. <i>flaccumfaciens</i> VKM Ас-1923<sup>T</sup>, <i>C. flaccumfaciens</i> pv. <i>poinsettiae</i> VKM Ас-1924<sup>T</sup>, <i>C. pusillum</i> VKM Ac-2099<sup>T</sup>, <i>C. herbarum</i> VKM Ac-2512<sup>T</sup>, and <i>Curtobacterium</i> sp. VKM Ac-1811. Each of the studied strains also contained a second, acidic, phosphate-free polysaccharide. NMR spectra of these polysaccharides differed, indicating the structural differences. Cell wall hydrolysates of all studied strains were found to contain rhamnose, mannose, glucose, galactose, and glucosamine. Further research will facilitate more detailed characterization of the composition of cell wall glycopolymers in <i>Curtobacterium</i> species, as well as evaluation of their taxonomic significance. The data on the polymer structure will contribute to understanding of the mechanisms of colonization and infection of higher organisms by <i>Curtobacterium</i> species and of bacterial interaction in microbial communities and with abiotic environmental objects.