Alexander M. Zakharenko

Hydrolysis of Fucoidan by Fucoidanase Isolated from the Marine Bacterium, Formosa algae

Intracellular fucoidanase was isolated from the marine bacterium, Formosa algae strain KMM 3553. The first appearance of fucoidan enzymatic hydrolysis products in a cell-free extract was detected after 4 h of bacterial growth, and maximal fucoidanase activity was observed after 12 h of growth. The fucoidanase displayed maximal activity in a wide range of pH values, from 6.5 to 9.1. The presence of Mg2+, Ca2+ and Ba2+ cations strongly activated the enzyme; however, Cu2+ and Zn2+ cations had inhibitory effects on the enzymatic activity. The enzymatic activity of fucoidanase was considerably reduced after prolonged (about 60 min) incubation of the enzyme solution at 45 °C. The fucoidanase catalyzed the hydrolysis of fucoidans from Fucus evanescens and Fucus vesiculosus, but not from Saccharina cichorioides. The fucoidanase also did not hydrolyze carrageenan. Desulfated fucoidan from F. evanescens was hydrolysed very weakly in contrast to deacetylated fucoidan, which was hydrolysed more actively compared to the native fucoidan from F. evanescens. Analysis of the structure of the enzymatic products showed that the marine bacteria, F. algae, synthesized an α-l-fucanase with an endo-type action that is specific for 1→4-bonds in a polysaccharide molecule built up of alternating three- and four-linked α-l-fucopyranose residues sulfated mainly at position 2.

Meroterpenoids from the alga-derived fungi Penicillium thomii maire and Penicillium lividum westling

Ten new austalide meroterpenoids (1-10) were isolated from the alga-derived fungi Penicillium thomii KMM 4645 and Penicillium lividum KMM 4663. Their structures were elucidated by extensive spectroscopic analysis and by comparison with related known compounds. The absolute configurations of some of the metabolites were assigned by the modified Moshers method and CD data. Compounds 1, 2, 8, and 9 were able to inhibit AP-1-dependent transcriptional activity in JB6 Cl41 cell lines at noncytotoxic concentrations. Austalides 1-5, 8, and 9 exhibited significant inhibitory activity against endo-1,3-β-D-glucanase from a crystalline stalk of the marine mollusk Pseudocardium sachalinensis.

POLYSACCHARIDES AND STEROLS FROM GREEN ALGAE Caulerpa lentillifera AND C. sertularioides

Sterols and polysaccharides of green alga Caulerpa lentillifera grown under laboratory conditions and in mariculture and polysaccharides of green alga C. sertularioides grown under natural conditions were studied. The sterol fraction consisted of C27-C29 steroidal alcohols with Δ5-unsaturation in the steroid core regardless of the growth conditions. The dominant (79.9%) steroid component of the sterol fraction was clionasterol. The water-soluble fraction of C. lentillifera grown under laboratory conditions was a mixture of 1,4-α- and 1,3-β-D-glucans and protein. The same fraction isolated from C. lentillifera grown in mariculture contained only protein. The water-soluble fraction of C. sertularioides grown under natural conditions contained 1,3;1,6-β-D-galactan sulfated at C2. The principal components of the base-soluble polysaccharide fractions from all algae samples were 1,4-α-D-glucans.

Deglycosylation of isoflavonoid glycosides from Maackia amurensis cell culture by β−D-glucosidase from Littorina sitkana hepatopancrease

Maakia amurensis (strain A-18) cell culture synthesizes a significant quantity of isoflavonoids, a large part of which consists of isoflavone glucosides and malonylglucosides. β−D-Hydrolase enzyme complexes from the marine mollusk Littorina sitkana and the marine mycelial fungus P. canescens were used to obtain isoflavones from their conjugated forms. The specificity of β−D-glucanases from L. sitkana for various glycosides was studied. The deglycosylation efficiency depended on the aglycon structure. The deglycosylated fraction of isoflavonoids obtained from M. amurensis cell culture exhibited antitumor activity.

Isolation from the marine mollusk Lambis sp. and catalytic properties of an alginate lyase with rare substrate specificity

Homogeneous alginate lyase with rare specificity exhibiting maximum activity at pH 5.0 and temperature range 40–55°C that catalyzed cleavage of 1→4 glycoside bonds between α-L-guluronic acid residues was isolated from liver-pancreas of the marine gastropod mollusk Lambis sp. The alginate lyase was classified as a poly-1→4-α-L-guluronate lyase (EC 4.2.2.11).