Microcystis Kützing ex Lemmermann is among the genera of cyanobacteria often associated to toxic blooms with the release of microcystins. A gene cluster codes for microcystin synthetases, which are involved in the biosynthesis of this toxin. The aim of the present study was to investigate the genetic diversity of the mcyB gene, specifically the B1 module, in Brazilian strains of Microcystis spp...

In August of 2003 and August of 2004, blooms of potentially toxic cyanobacteria Microcystis spp. persisted in western Lake Erie. Samples collected from the bloom were analyzed for the cyanobacterial toxin microcystin and the presence of Microcystis spp. cells. Estimates of microcystin toxicity exceeding 1 microg L(-1) (microcystin-LR activity equivalents), the safety limit set by the World Heal...

Occurrence and toxicity of Microcystis spp. were measured by ELISA in three impoundments of the Huron River in southeast Michigan, USA. Assays were conducted weekly from June through October 2005. Additional samples were collected to assess microcystin concentrations throughout the drinking water treatment process at the Ann Arbor Water Treatment Facility. Water column stability, nutrient conce...

We developed a simple and one-step method to prepare biocompatible composites from cellulose (CEL) and chitosan (CS). [BMIm(+)Cl(-)], an ionic liquid (IL), was used as a green solvent to dissolve and prepare the [CEL+CS] composites. Since majority (>88%) of IL used was recovered for reuse by distilling the aqueous washings of [CEL+CS], the method is recyclable. XRD, FTIR, NIR, (13)C CP-MAS-NMR ...

The increasing incidence of mass developments of Cyanobacteria in freshand brackish water is a matter of growing concern due to the production of toxins that threaten human and livestock health. The toxins that are produced by freshwater Cyanobacteria comprise hepatotoxins (cyclic peptides such as microcystins and nodularin, as well as alkaloids such as cylindrospermopsin) and neurotoxins (alka...

Regular occurrences of the cyanobacterium Plankcotlllix rubescens have been observed in several lakes that have undergone recent re-oligotrophication, e.g. Lake Ammersee. Planktothn",~ species are known to produce microcystins, potent pllOsphatase inhibitors that have been associated with morbidities and mortalities in hUinans and animals. The aim of this study was to characterise the temporal ...

The cluster of microcystin synthetase genes from Anabaena strain 90 was sequenced and characterized. The total size of the region is 55.4 kb, and the genes are organized in three putative operons. The first operon (mcyA-mcyB-mcyC) is transcribed in the opposite direction from the second operon (mcyG-mcyD-mcyJ-mcyE-mcyF-mcyI) and the third operon (mcyH). The genes mcyA, mcyB, and mcyC encode non...

An amperometric immunoanalysis system based on monoclonal antibodies immobilized on Sepharose beads and packed into a micro-immunocolumn was developed for the quantification of microcystin-LR. Microcystin-LR (MCLR) was used as a reference microcystin variant. Inside the immunocolumn, free microcystins and microcystin-horseradish peroxidase (tracer) were sequentially captured by the immobilized ...

Microcystin, a hepatotoxin known to be the cause of animal and human deaths, is produced by the bloom-forming cyanobacterium Microcystis aeruginosa in freshwater bodies worldwide. The toxin is produced nonribosomally via a multifunctional enzyme complex, consisting of both peptide synthetase and polyketide synthase modules coded for by the mcy gene cluster. The recent identification of the mcy ...

Cyanobacterial blooms are of great importance because of the toxic effects that these microorganisms are able to induce, particularly on aquatic organisms. Microcystins (MCs) are the principal toxins biosynthesized by cyanobacteria and are powerful inhibitors of the protein phosphatases 1 and 2A. Zooplankton filter feeders such as cladocerans are directly affected by MCs as a result of ingestio...