Some Novel Aerobic Heparin-Degrading Bacterial Isolates

Complete genome sequence of the gliding, heparinolytic Pedobacter saltans type strain (113)

Pedobacter saltans Steyn et al. 1998 is one of currently 32 species in the genus Pedobacter within the family Sphingobacteriaceae. The species is of interest for its isolated location in the tree of life. Like other members of the genus P. saltans is heparinolytic. Cells of P. saltans show a peculiar gliding, dancing motility and can be distinguished from other Pedobacter strains by their ability to utilize glycerol and the inability to assimilate D-cellobiose. The genome presented here is only the second completed genome sequence of a type strain from a member of the family Sphingobacteriaceae to be published. The 4,635,236 bp long genome with its 3,854 protein-coding and 67 RNA genes consists of one chromosome, and is a part of the Genomic Encyclopedia of Bacteria and Archaea project.

Pedobacter duraquae sp. nov., Pedobacter westerhofensis sp. nov., Pedobacter metabolipauper sp. nov., Pedobacter hartonius sp. nov. and Pedobacter steynii sp. nov., isolated from a hard-water rivulet

Five isolates that were related phylogenetically to members of the genus Pedobacter were isolated from freshwater of the hard-water creek Westerhöfer Bach, North Germany. The five strains (WB 2.1-25T, WB 2.3-71T, WB 3.3-3T, WB 3.3-22T and WB 2.3-45T) were Gram-negative and chemoheterotrophic, with rod-shaped cells. Most of their metabolic properties matched those given in the description of the genus Pedobacter. Consistent with the genus description, their fatty acids included mainly iso-C15 : 0 and summed feature 3 (C16 : 1 ω7c, iso-C15 : 0 2-OH or both); C16 : 1 ω5c, C16 : 0, iso-C15 : 0 3-OH, C16 : 0 3-OH and iso-C17 : 0 3-OH were present in smaller amounts. The major isoprenoid quinone was menaquinone 7. With one exception, binary similarity values of the almost complete 16S rRNA gene sequences determined among the isolates as well as between the isolates and type strains of Pedobacter species were lower than 98.5 %. The only exception was the close relationship between Pedobacter caeni DSM 16990T and strain WB 2.3-45T (99.2 % similarity). DNA–DNA reassociation values determined for this pair of strains was 29.8 %, indicating that strain WB 2.3-45T represents a unique genospecies. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strains WB 2.1-25T and WB 2.3-71T form a group that is moderately related to P. caeni and strain WB 2.3-45T (98.5 % similarity). Strains WB 3.3-3T and WB 3.3-22T (98.5 % similarity) branched separately from these four organisms. The five phylogenetically isolated strains differed from each other as well as from the type strain of the type species (Pedobacter heparinus DSM 2366T) and some related representatives of the genus in several metabolic reactions and cultural parameters. On the basis of phenotypic and phylogenetic distinctiveness, five novel species are proposed: Pedobacter duraquae sp. nov., with WB 2.1-25T (=DSM 19034T=CIP 109481T) as the type strain; Pedobacter westerhofensis sp. nov., with WB 3.3-22T (=DSM 19036T=CIP 109479T) as the type strain; Pedobacter metabolipauper sp. nov., with WB 2.3-71T (=DSM 19035T=CIP 109480T) as the type strain; Pedobacter hartonius sp. nov., with WB 3.3-3T (=DSM 19033T=CIP 109468T) as the type strain; and Pedobacter steynii sp. nov., with WB 2.3-45T (=DSM 19110T=CIP 109507T) as the type strain.

Reclassification of [Flavobacterium] ferrugineum as Terrimonas ferruginea gen. nov., comb. nov., and description of Terrimonas lutea sp. nov., isolated from soil

Strain DYT, which was isolated from garden soil in Japan, was subjected to a polyphasic taxonomic study. Sequence analysis of the 16S rRNA gene and the GyrB protein revealed that the closest relative of strain DYT was [Flavobacterium] ferrugineum Sickles and Shaw 1934, with 94.8 and 90.1 % similarity, respectively. The two strains had similar chemotaxonomic characteristics, with menaquinone 7 as the major quinone system, 47.2–48.9 mol% DNA G+C content and 15 : 0 iso, 15 : 1 iso, 17 : 0 iso 3-OH and summed feature 3 as the major fatty acids. Based on genotypic and phenotypic characteristics, [Flavobacterium] ferrugineum IAM 15098T could be clearly differentiated from other members of the genus Flavobacterium. Strain DYT and [Flavobacterium] ferrugineum IAM 15098T could be easily distinguished from neighbouring taxa by morphological features (non-motile, non-gliding and non-filamentous single cells). Therefore, it is proposed that [Flavobacterium] ferrugineum IAM 15098T and strain DYT represent two separate species of a new genus, Terrimonas gen. nov., with the names Terrimonas ferruginea comb. nov. (type species; type strain IAM 15098T=ATCC 13524T) and Terrimonas lutea sp. nov. (type strain DYT=IAM 15284T=CCTCC AB205006T), respectively.

Enzymatic degradation of glycosaminoglycans

Glycosaminoglycans (GAGs) play an intricate role in the extracellular matrix (ECM), not only as soluble components and polyelectrolytes, but also by specific interactions with growth factors and other transient components of the ECM. Modifications of GAG chains, such as isomerization, sulfation, and acetylation, generate the chemical specificity of GAGs. GAGs can be depolymerized enzymatically either by eliminative cleavage with lyases (EC 4.2.2.-) or by hydrolytic cleavage with hydrolases (EC 3.2.1.-). Often, these enzymes are specific for residues in the polysaccharide chain with certain modifications. As such, the enzymes can serve as tools for studying the physiological effect of residue modifications and as models at the molecular level of protein-GAG recognition. This review examines the structure of the substrates, the properties of enzymatic degradation, and the enzyme substrate-interactions at a molecular level. The primary structure of several GAGs is organized macroscopically by segregation into alternating blocks of specific sulfation patterns and microscopically by formation of oligosaccharide sequences with specific binding functions. Among GAGs, considerable dermatan sulfate, heparin and heparan sulfate show conformational flexibility in solution. They elicit sequence-specific interactions with enzymes that degrade them, as well as with other proteins, however, the effect of conformational flexibility on protein-GAG interactions is not clear. Recent findings have established empirical rules of substrate specificity and elucidated molecular mechanisms of enzyme-substrate interactions for enzymes that degrade GAGs. Here we propose that local formation of polysaccharide secondary structure is determined by the immediate sequence environment within the GAG polymer, and that this secondary structure, in turn, governs the binding and catalytic interactions between proteins and GAGs.