Fish are exposed to numerous stressors in the environment including pollution, bacterial and viral agents, and toxic substances. Our study with common carps leveraged an integrated approach (i.e., histology, biochemical and hematological measurements, and analytical chemistry) to understand how cyanobacteria interfere with the impact of a model viral agent, Carp sprivivirus (SVCV), on fish. In addition to the specific effects of a single stressor (SVCV or cyanobacteria), the combination of both stressors worsens markers related to the immune system and liver health. Solely combined exposure resulted in the rise in the production of immunoglobulins, changes in glucose and cholesterol levels, and an elevated marker of impaired liver, alanine aminotransferase (ALT). Analytical determination of the cyanobacterial toxin microcystin-LR (MC-LR) and its structurally similar congener MC-RR and their conjugates showed that SVCV affects neither the levels of MC in the liver nor the detoxification capacity of the liver. MC-LR and MC-RR were depurated from liver mostly in the form of cysteine conjugates (MC-LR-Cys, MC-RR-Cys) in comparison to glutathione conjugates (LR-GSH, RR-GSH). Our study brought new evidence that cyanobacteria worsen the effect of viral agents. Such inclusion of multiple stressor concept helps us to understand how and to what extent the relevant environmental stressors co-influence the health of the fish population.

• Keywords
• conjugates, cyanobacteria, immune system, microcystins, spring viraemia of carp,
• MeSH
• Water Pollutants, Chemical toxicity   MeSH
• Carps microbiology   MeSH
• Microcystis chemistry   MeSH
• Microcystins toxicity   MeSH
• Fish Diseases chemically induced   physiopathology   MeSH
• Seasons MeSH
• Severity of Illness Index * MeSH
• Toxicity Tests MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Water Pollutants, Chemical MeSH
• Microcystins MeSH

Aquatic ecosystems are under increasing stress from global anthropogenic and natural changes, including climate change, eutrophication, ocean acidification, and pollution. In this critical review, we synthesize research on the microbiota of aquatic vertebrates and discuss the impact of emerging stressors on aquatic microbial communities using two case studies, that of toxic cyanobacteria and microplastics. Most studies to date are focused on host-associated microbiomes of individual organisms, however, few studies take an integrative approach to examine aquatic vertebrate microbiomes by considering both host-associated and free-living microbiota within an ecosystem. We highlight what is known about microbiota in aquatic ecosystems, with a focus on the interface between water, fish, and marine mammals. Though microbiomes in water vary with geography, temperature, depth, and other factors, core microbial functions such as primary production, nitrogen cycling, and nutrient metabolism are often conserved across aquatic environments. We outline knowledge on the composition and function of tissue-specific microbiomes in fish and marine mammals and discuss the environmental factors influencing their structure. The microbiota of aquatic mammals and fish are highly unique to species and a delicate balance between respiratory, skin, and gastrointestinal microbiota exists within the host. In aquatic vertebrates, water conditions and ecological niche are driving factors behind microbial composition and function. We also generate a comprehensive catalog of marine mammal and fish microbial genera, revealing commonalities in composition and function among aquatic species, and discuss the potential use of microbiomes as indicators of health and ecological status of aquatic ecosystems. We also discuss the importance of a focus on the functional relevance of microbial communities in relation to organism physiology and their ability to overcome stressors related to global change. Understanding the dynamic relationship between aquatic microbiota and the animals they colonize is critical for monitoring water quality and population health.

• Keywords
• aquatic mammals, biomonitoring, ecosystem health, fish, microbiome, stressors,
• Publication type
• Journal Article MeSH
• Review MeSH

Man-made shallow fishponds in the Czech Republic have been facing high eutrophication since the 1950s. Anthropogenic eutrophication and feeding of fish have strongly affected the physicochemical properties of water and its aquatic community composition, leading to harmful algal bloom formation. In our current study, we characterized the phytoplankton community across three eutrophic ponds to assess the phytoplankton dynamics during the vegetation season. We microscopically identified and quantified 29 cyanobacterial taxa comprising non-toxigenic and toxigenic species. Further, a detailed cyanopeptides (CNPs) profiling was performed using molecular networking analysis of liquid chromatography-tandem mass spectrometry (LC-MS/MS) data coupled with a dereplication strategy. This MS networking approach, coupled with dereplication, on the online global natural product social networking (GNPS) web platform led us to putatively identify forty CNPs: fourteen anabaenopeptins, ten microcystins, five cyanopeptolins, six microginins, two cyanobactins, a dipeptide radiosumin, a cyclooctapeptide planktocyclin, and epidolastatin 12. We applied the binary logistic regression to estimate the CNPs producers by correlating the GNPS data with the species abundance. The usage of the GNPS web platform proved a valuable approach for the rapid and simultaneous detection of a large number of peptides and rapid risk assessments for harmful blooms.

• Keywords
• cyanobacteria, cyanopeptides, dereplication strategy, global natural product social networking (GNPS), harmful bloom, liquid chromatography-tandem mass spectrometry,
• MeSH
• Bacterial Toxins analysis   toxicity   MeSH
• Spectrometry, Mass, Electrospray Ionization * MeSH
• Risk Assessment MeSH
• Metabolomics MeSH
• Water Microbiology MeSH
• Microbiota MeSH
• Environmental Monitoring * MeSH
• Marine Toxins analysis   toxicity   MeSH
• Online Social Networking * MeSH
• Population Dynamics MeSH
• Seasons MeSH
• Ponds microbiology   MeSH
• Cyanobacteria classification   growth & development   metabolism   MeSH
• Harmful Algal Bloom * MeSH
• Tandem Mass Spectrometry * MeSH
• Chromatography, High Pressure Liquid * MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Geographicals
• Czech Republic MeSH
• Names of Substances
• Bacterial Toxins MeSH
• Marine Toxins MeSH

Changes in ecological and environmental factors lead to an increased occurrence of cyanobacterial water blooms, while secondary metabolites-producing cyanobacteria pose a threat to both environmental and human health. Apart from oral and dermal exposure, humans may be exposed via inhalation and/or swallowing of contaminated water and aerosols. Although many studies deal with liver toxicity, less information about the effects in the respiratory system is available. We investigated the effects of a prevalent cyanotoxin, microcystin-LR (MC-LR), using respiratory system-relevant human bronchial epithelial (HBE) cells. The expression of specific organic-anion-transporting polypeptides was evaluated, and the western blot analysis revealed the formation and accumulation of MC-LR protein adducts in exposed cells. However, MC-LR up to 20 μM neither caused significant cytotoxic effects according to multiple viability endpoints after 48-h exposure, nor reduced impedance (cell layer integrity) over 96 h. Time-dependent increase of putative MC-LR adducts with protein phosphatases was not associated with activation of mitogen-activated protein kinases ERK1/2 and p38 during 48-h exposure in HBE cells. Future studies addressing human health risks associated with inhalation of toxic cyanobacteria and cyanotoxins should focus on complex environmental samples of cyanobacterial blooms and alterations of additional non-cytotoxic endpoints while adopting more advanced in vitro models.

• Keywords
• 16HBE14o-, mitogen-activated protein kinase, HBE1, OATP, cytotoxicity, human bronchial epithelial cells, in vitro, microcystin-LR,
• MeSH
• Bronchi cytology   MeSH
• Cell Line MeSH
• Epithelial Cells drug effects   metabolism   MeSH
• Extracellular Signal-Regulated MAP Kinases metabolism   MeSH
• Humans MeSH
• Microcystins toxicity   MeSH
• p38 Mitogen-Activated Protein Kinases metabolism   MeSH
• Marine Toxins toxicity   MeSH
• Organic Anion Transporters genetics   MeSH
• Signal Transduction drug effects   MeSH
• Cell Survival drug effects   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• cyanoginosin LR MeSH Browser
• Extracellular Signal-Regulated MAP Kinases MeSH
• Microcystins MeSH
• p38 Mitogen-Activated Protein Kinases MeSH
• Marine Toxins MeSH
• Organic Anion Transporters MeSH

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