Genetic diversity of Acanthamoeba isolated from ocean sediments

Genetic diversity of 18 Acanthamoeba isolates from ocean sediments was evaluated by comparing mitochondrial (mt) DNA RFLP, 18S rDNA sequences and by examining their cytopathic effects on human corneal epithelial cells versus reference strains. All isolates belonged to morphologic group II. Total of 16 restriction phenotypes of mtDNA from 18 isolates demonstrated the genetic diversity of Acanthamoeba in ocean sediments. Phylogenetic analysis using 18s rDNA sequences revealed that the 18 isolates were distinct from morphological groups I and III. Fifteen isolates showed close relatedness with 17 clinical isolates and A. castellanii Castellani and formed a lineage equivalent to T4 genotype of Byers' group. Two reference strains from ocean sediment, A. hatchetti BH-2 and A. griffini S-7 clustered unequivocally with these 15 isolates. Diversity among isolates was also evident from their cytopathic effects on human corneal cells. This is the first time describing Acanthamoeba diversity in ocean sediments in Korea.

Antitumor screening of deep ocean water and sediment derived fungi and primary investigation of their secondary metabolites / 中国海洋药物

Objective The cytotoxic microbial strains isolated from the deep ocean water and sediments were screened,and the secondary metabolites of bioactive fungus c2b were investi- gated.Methods Active bioactive microbial strains were screened using brine shrimp and chro- nic medulla leucocythemia leukocythemia(K562)cell line.The cytotoxic components of fun- gus c2b were isolated by bioassay-guided fractionation and solvent extraction,silica gel col- umn chromatography and preparative HPLC.Their structures were established by pbysico- chemical properties and spectral analyses.The cytotoxicities of compounds were evaluated by SRB method.Results and Conclusion Twenty-nine strains of fungi were isolated.Among them,seven strains showed cytotoxic activities.Six compounds(1～6)were isolated and i- dentified as N-acetyl histamine(1),chrysogine(2),ergosterol peroxide(3),5,8-epidioxy- 24-methylcholesta-6,22-dien-3?-ol(4)cerevisterol(5)and(4E,8E)-N-[(2'R,3'E)-2'-hy- droxy-3'-hexadecenoyl]-1-O-?-D-glycopyranosyl-9-methyl-4,8-sphingadiene(6),respective- ly.Compound 3 and 4 showed median cytotoxicity.