Influence of viscous Rhodella grisea (Rhodophyceae) proteoglycan on chemically induced cough reflex.

An algal extracellular biopolymer (over 8.5 × 10(5)Da) composed of carbohydrates (52%) and protein (∼13%) has been isolated from a red alga Rhodella grisea growing in natural conditions by concentration of water medium, alcohol precipitation, dialysis and freeze-drying. This mucilagineous biopolymer contained xylose and its 3-O- and 4-O-methyl derivatives (∼63%), galactose (∼12%), glucuronic acid (11-12%), glucose (∼5%), rhamnose (∼4%), fucose (∼3-4%) and low content of others accompaning sugars.

Zygospore formation between homothallic and heterothallic strains of Closterium.

Zygospore formation in different strains of the Closterium peracerosum-strigosum-littorale complex was examined in this unicellular isogamous charophycean alga to shed light on gametic mating strains in this taxon, which is believed to share a close phylogenetic relationship with land plants. Zygospores typically form as a result of conjugation between mating-type plus (mt(+)) and mating-type minus (mt(-)) cells during sexual reproduction in the heterothallic strain, similar to Chlamydomonas. However, within clonal cells, zygospores are formed within homothallic strains, and the majority of these zygospores originate as a result of conjugation of two recently divided sister gametangial cells derived from one vegetative cell.

Extracellular glycoconjugates produced by cyanobacterium Wollea saccata.

In order to survive in a highly competitive environment, freshwater or marine phototrophic microorganisms have to develop defense strategies that result in a tremendous diversity of compounds from different metabolic pathways. Recent trends in drug research from natural sources have shown that algae and cyanobacteria are promising organisms to furnish novel biochemically active compounds. In this study, we have analysed the extracellular mucilaginous proteoglycan produced by fresh-water heterocytous filamentous cyanobacterium Wollea saccata, strain Hindák 2000/18.