Microcystin-RR Like Toxin Identified in the Cyanobacterium Anabaena flos-aquae Strain CCAP 1403/13B Culture

Cyanobacteria abound in freshwaters in Ghana, including those used for the supply of drinking water. However, there have been no studies on their toxicity, the toxins they produce and their attending public health effects. As part of research activities to identify cyanobacteria and cyanotoxins associated with four reservoirs (Weija, Kpong, Owabi and Barekese), used for the production of drinking water in Ghana, Anabaena flos-aquae, a toxic cyanobacterium, was cultured in the laboratory with the objective of identifying potential cyanotoxins that may be associated with some of the cyanobacteria commonly found in Ghanaian waters. Cultures were kept in agrowth chamber with continuous illumination at 20 ìmol photon/m2/s and constant aeration at a temperature of 25 oC. High pressure liquid chromatography (HPLC) analysis of extract from the culture of Anabaena flos-aquae strain CCAP 1403/13B produced a toxin with a retention time similar to microcystin-RR external standard. The concentration of microcystin-RR quantified from Anabaena flos-aquae was 10.6 ìg/g DW. The biomass of lyophilized cells extracted was 52 mg. Anabaena flos-aquae is mainly known to produce neurotoxins, notably anatoxin-a and anatoxin-a(s). Anabaena and Microcystis were reported to be responsible for the lethal poisoning of over 2000 people in Bahia, Brazil through drinking water which resulted in the death of 88 children fromgastro-enteritis over a period of 42 days

Allelopathic interactions of linoleic acid and nitric oxide increase the competitive ability of Microcystis aeruginosa

The frequency and intensity of cyanobacterial blooms are increasing worldwide with major societal and economic costs. Interactions between toxic cyanobacteria and eukaryotic algal competitors can affect toxic bloom formation, but the exact mechanisms of interspecies interactions remain unknown. Using metabolomic and proteomic profiling of co-cultures of the toxic cyanobacterium Microcystis aeruginosa with a green alga as well as of microorganisms collected in a Microcystis spp. bloom in Lake Taihu (China), we disentangle novel interspecies allelopathic interactions. We describe an interspecies molecular network in which M. aeruginosa inhibits growth of Chlorella vulgaris, a model green algal competitor, via the release of linoleic acid. In addition, we demonstrate how M. aeruginosa takes advantage of the cell signaling compound nitric oxide produced by C. vulgaris, which stimulates a positive feedback mechanism of linoleic acid release by M. aeruginosa and its toxicity. Our high-throughput system-biology approach highlights the importance of previously unrecognized allelopathic interactions between a broadly distributed toxic cyanobacterial bloom former and one of its algal competitors

ELIXIR and Toxicology: a community in development [version 2; peer review: 2 approved]

Toxicology has been an active research field for many decades, with academic, industrial and government involvement. Modern omics and computational approaches are changing the field, from merely disease-specific observational models into target-specific predictive models. Traditionally, toxicology has strong links with other fields such as biology, chemistry, pharmacology, and medicine. With the rise of synthetic and new engineered materials, alongside ongoing prioritisation needs in chemical risk assessment for existing chemicals, early predictive evaluations are becoming of utmost importance to both scientific and regulatory purposes. ELIXIR is an intergovernmental organisation that brings together life science resources from across Europe. To coordinate the linkage of various life science efforts around modern predictive toxicology, the establishment of a new ELIXIR Community is seen as instrumental. In the past few years, joint efforts, building on incidental overlap, have been piloted in the context of ELIXIR. For example, the EU-ToxRisk, diXa, HeCaToS, transQST, and the nanotoxicology community have worked with the ELIXIR TeSS, Bioschemas, and Compute Platforms and activities. In 2018, a core group of interested parties wrote a proposal, outlining a sketch of what this new ELIXIR Toxicology Community would look like. A recent workshop (held September 30th to October 1st, 2020) extended this into an ELIXIR Toxicology roadmap and a shortlist of limited investment-high gain collaborations to give body to this new community. This Whitepaper outlines the results of these efforts and defines our vision of the ELIXIR Toxicology Community and how it complements other ELIXIR activities

Cyanobacteria species identified in the Weija and Kpong reservoirs, Ghana, and their implications for drinking water quality with respect to microcystin

The Kpong and Weija reservoirs supply drinking water to Accra, Ghana. This study was conducted to identify the cyanobacteria present in these reservoirs and to ascertain whether current treatment processes removewhole cyanobacteria cells from the drinking water produced. Cyanotoxins are mostly cell bound and could easily be removed during water treatment. However, certain water treatment practices, such as pre-chlorinationand the use of algicides, lead to lyses of cyanobacteria cells and the release of toxins into the water. The study shows that the water treatment process in the two reservoirs is not effective in the removal of all cyanobacterial cells. Out of the six cyanobacteria species identified in the reservoirs, four produce toxins: Anabaena flos-aquae, Cylindrospermopsis raciborskii, Microcystis aeruginosa and Planktothrix agardhii. These four species constituted about 70–90% of the total algal biomass at all the water treatment stages, including the final product supplied to consumers.Preliminary toxicological analysis of intracellular toxin of samples from the raw water intakes of the two reservoirs indicated the presence of microcystin, with the highest concentration (3.21ìg l–1) found in the WeijaReservoir. This study provides the first report of microcystins in drinking water supplies in Ghana

Slp1 regulates platelet secretion

The small guanine-nucleotide–binding protein Rap1 plays a key role in platelet aggregation and hemostasis, and we recently identified Rap1GAP2 as the only GTPase-activating protein of Rap1 in platelets. In search of Rap1GAP2-associated proteins, we performed yeast-2-hybrid screening and found synaptotagmin-like protein 1 (Slp1) as a new binding partner. We confirmed the interaction of Rap1GAP2 and Slp1 in transfected COS-1 and HeLa cells and at endogenous level in human platelets. Mapping studies showed that Rap1GAP2 binds through amino acids T524-K525-X-T527 within its C-terminus to the C2A domain of Slp1. Slp1 contains a Rab27-binding domain, and we demonstrate that Rap1GAP2, Slp1, and Rab27 form a trimeric complex in transfected cells and in platelets. Purified Slp1 dose-dependently decreased dense granule secretion in streptolysin-O–permeabilized platelets stimulated with calcium or guanosine 5′-O-[gamma-thio] triphosphate. The isolated C2A domain of Slp1 had a stimulatory effect on granule secretion and reversed the inhibitory effect of full-length Slp1. Purified Rap1GAP2 augmented dense granule secretion of permeabilized platelets, whereas deletion of the Slp1-binding TKXT motif abolished the effect of Rap1GAP2. We conclude that Slp1 inhibits dense granule secretion in platelets and that Rap1GAP2 modulates secretion by binding to Slp1.Science Foundation IrelandDeutsche ForschungsgemeinschaftExcellence Cluster Cardio-Pulmonary Syste