Extracellular polysaccharides and polysaccharide-containing biopolymers fromAzospirillumspecies: properties and the possible role in interaction with plant roots

Abstract

This paper reviews the results obtained in studies of the extracellular polysaccharides, lipopolysaccharide-protein complexes, polysaccharide-lipid complexes, lipopolysaccharides, and O-specific polysaccharides from bacteria of the genus Azospirillum. On the basis of present knowledge, the possible roles of the extracellular polysaccharides and polysaccharide-containing complexes of azospirilla in interaction with the roots of plants are discussed. Some pieces of evidence are considered in light of the lectin hypothesis originally proposed for the legume-Rhizobium symbiosis. In the context of these views of Azospirillumcereal associative pairs, a key process at the early stages of the interaction is the specific reaction of cereal root lectins with the extracellular polysaccharide components, containing N-acetyl-D-glucosamine as part of their structure.

Primary Structure and Carbohydrate Binding Specificity of a Potent Anti-HIV Lectin Isolated from the Filamentous Cyanobacterium Oscillatoria agardhii

“…mannose-binding legume lectins (3), monocot mannose-binding lectins (4), mannose-binding jacalin-related lectins (5), and type 2-ribosome-inactivating proteins (6), based on their structural scaffolds and the mode of recognition of carbohydrates (7). Some higher plant lectins play a key role for self defense against insects or for symbiosis with bacterial symbionts (8,9). Monocot mannose-binding lectins also inhibit HIV 3 infection of human lymphocytes in the higher ng/ml range (10).…”

Trace cobalt speciation in bacteria and at enzymic active sites using emission Mössbauer spectroscopy

“…In view of that, it may be inferred that the observed changes reflecting cobalt(II) metabolism in A. brasilense Sp245 within an hour (see Fig. 1a,b and Table 1, samples 1,2) are localised within the bacterial cell wall containing PS-, LPS-and protein-containing moieties typical for azospirilla [19,23,24,25].…”

“…brasilense Sp245 cells Binding of heavy metals by the cell surface in Gram-negative bacteria is mediated primarily by capsular polysaccharide (PS) and lipopolysaccharide (LPS) materials [21,22]. The latter are characteristic for A. brasilense as well and, along with its outer-membrane proteins, are believed to be involved in contact interactions with plant roots and in bacterial cell aggregation [23,24,25].…”

Revised structure of the repeating unit of the O-specific polysaccharide from Azospirillum lipoferum strain SpBr17

“…1 OAc β-D-Glcp ⎜ These results have been cited repeatedly by researchers working on Azospirillum surface polysaccharides. [5][6][7][8]10 Recently, we have published the structure of A. lipoferum SpBr17 lipid A. 11 During preparation of the lipid A moiety, a large amount of the O-specific polysaccharide was obtained.…”