Massive toxic blooms of cyanobacteria represent a major threat to water supplies worldwide. Here, the biological activities of lipopolysaccharide (LPS) isolated from Microcystis aeruginosa, the most prominent cyanobacteria in water bloom, were studied. LPS was isolated from complex environmental water bloom samples dominated by M. aeruginosa, and from laboratory cultures of non-axenic as well as axenic M. aeruginosa strains PCC7806 and HAMBI/UHCC130. Employing human blood-based in vitro tests, the LPS isolated from complex water bloom revealed the priming of both major blood phagocyte population monocytes and polymorphonuclear leukocytes documented by the increased surface expression of CD11b and CD66b. This was accompanied by a water bloom LPS-mediated dose-dependent induction of tumor necrosis factor α, interleukin-1β, and interleukin-6 production. In accordance with its priming effects, water bloom LPS induced significant activation of p38 and ERK1/2 kinases, as well as NF-κB phosphorylation, in isolated polymorphonuclear leukocytes. Interestingly, the pro-inflammatory potential of LPS from the axenic strain of M. aeruginosa was not lower compared to that of LPS isolated from non-axenic strains. In contrast to the biological activity, water bloom LPS revealed almost twice higher pyrogenicity levels compared to Escherichia coli LPS, as analyzed by the PyroGene test. Moreover, LPS from the non-axenic culture exhibited higher endotoxin activity in comparison to LPS from axenic strains. Taking the above findings together, M. aeruginosa LPS can contribute to the health risks associated with contamination by complex water bloom mass.

• Keywords
• cyanobacteria, endotoxin, inflammation, leukocytes, lipopolysaccharide, water bloom,
• MeSH
• CD11b Antigen metabolism   MeSH
• Antigens, CD metabolism   MeSH
• Cytokines blood   MeSH
• Eutrophication MeSH
• GPI-Linked Proteins metabolism   MeSH
• Cells, Cultured MeSH
• Laboratories MeSH
• Leukocytes, Mononuclear drug effects   metabolism   MeSH
• Humans MeSH
• Lipopolysaccharides toxicity   MeSH
• Microcystis * MeSH
• Cell Adhesion Molecules metabolism   MeSH
• Immunity, Innate drug effects   MeSH
• Pyrogens toxicity   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• CD11b Antigen MeSH
• Antigens, CD MeSH
• CEACAM8 protein, human MeSH Browser
• Cytokines MeSH
• GPI-Linked Proteins MeSH
• ITGAM protein, human MeSH Browser
• Lipopolysaccharides MeSH
• Cell Adhesion Molecules MeSH
• Pyrogens MeSH

Pectinatella magnifica, an invasive bryozoan, might significantly affect ecosystem balance due to its massive occurrence in many areas in Europe and other parts of the world. Biological and chemical analyses are needed to get complete information about the impact of the animal on the environment. In this paper, we aimed to evaluate in vitro cytotoxic effects of five extracts prepared from P. magnifica using LDH assay on THP-1 cell line. Antimicrobial activities of extracts against 22 different bacterial strains were tested by microdilution method. Our study showed that all extracts tested, except aqueous portion, demonstrated LD50 values below 100 μg/mL, which indicates potential toxicity. The water extract of P. magnifica with LD50 value of 250 μg/mL also shows potentially harmful effects. Also, an environmental risk resulting from the presence and increasing biomass of potentially toxic benthic cyanobacteria in old colonies should not be underestimated. Toxicity of Pectinatella extracts could be partially caused by presence of Aeromonas species in material, since we found members of these genera as most abundant bacteria associated with P. magnifica. Furthermore, P. magnifica seems to be a promising source of certain antimicrobial agents. Its methanolic extract, hexane, and chloroform fractions possessed selective inhibitory effect on some potential pathogens and food spoiling bacteria in the range of MIC 0.5-10 mg/mL. Future effort should be made to isolate and characterize the content compounds derived from P. magnifica, which could help to identify the substance(s) responsible for the toxic effects of P. magnifica extracts.

• Keywords
• Aeromonas, Bryozoa, Pectinatella magnifica, antimicrobial activity, bacteria, cyanobacteria, invasive species, toxicity,
• MeSH
• Aeromonas chemistry   MeSH
• Anti-Bacterial Agents chemistry   pharmacology   MeSH
• Bacteria drug effects   MeSH
• Bacterial Toxins pharmacology   MeSH
• Bryozoa chemistry   microbiology   MeSH
• Cell Line MeSH
• Chloroform pharmacology   MeSH
• Hexanes pharmacology   MeSH
• Humans MeSH
• Methanol pharmacology   MeSH
• Microbial Sensitivity Tests MeSH
• Toxicity Tests MeSH
• Cell Survival drug effects   MeSH
• Introduced Species MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Anti-Bacterial Agents MeSH
• Bacterial Toxins MeSH
• Chloroform MeSH
• Hexanes MeSH
• Methanol MeSH