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Abstract Cyanobacteria can produce groups of structurally and functionally unrelated but highly potent toxins. Cyanotoxins are used in multiple research endeavours, either for direct investigation of their toxicologic properties, or as functional analogues for various biochemical and physiological processes. This paper presents occupational safety guidelines and recommendations for personnel working in field, laboratory or industrial settings to produce and use purified cyanotoxins and toxic cyanobacteria, from bulk harvesting of bloom material, mass culture of laboratory isolates, through routine extraction, isolation and purification. Oral, inhalational, dermal and parenteral routes are all potential occupational exposure pathways during the various stages of cyanotoxin production and application. Investigation of toxicologic or pharmacologic properties using in vivo models may present specific risks if radiolabelled cyanotoxins are employed, and the potential for occupational exposure via the dermal route is heightened with the use of organic solvents as vehicles. Inter- and intra-national transport of living cyanobacteria for research purposes risks establishing feral microalgal populations, so disinfection of culture equipment and destruction of cells by autoclaving, incineration and/or chlorination is recommended in order to prevent viable cyanobacteria from escaping research or production facilities.

Research has been conducted on the extracellular copper regulating DNA binding activity of the CopY repressor. The mechanism for copper exchange between CopY and a copper chaperone CopZ has been investigated and the results are reported.

X-ray crystallography, nuclear magnetic resonance spectroscopy and UV spectrometry were done to characterize the synthesized monodentate 1,1-dimethylguanidine complexes of hard (NH3)5Co(super III), soft dienPt and intermediate (NH3)5Os(super III) as models for the study of arginine-metal binding. The observed reactivity of cyanamide which has been bonded to soft or hard metal electrophiles toward nucleophilic attack by either ammonia or hydroxide to yield a guanidine ligand indicated that the electrophilicity of nitriles can be enhanced by metals.

Analysis of the influence of metalation on amide-iminol tautomerism reveals that N-metalation of amides stabilize both iminol and amide tautomeric structures. DienPt(II) exhibits capacity of metalate amides at nitrogen and oxygen, but O-metalation produces only one tautomeric form. X-ray studies enable the comparison of structures and properties of two N-metalated compounds. Reinvestigation of a Rh complex contradicts its reported iminol tautomeric form and the new data suggest an alternative amide tautomeric form.

The syntheses and properties of isomeric (diethylenetriamine)platinum(II) complexes of 1, 1-dimethylurea (DMU) bound through nitrogen or oxygen were reported. Nuclear magnetic resonance and infrared spectroscopy showed that the N-bonded DMU complex exists in solution and in the solid state as the amide tautomer (dienPtNH2COR)2+ (R = NMe2), rather than the imidol tautomer which prevails for acetamide. Both isomerization and solvolysis likely proceed via the amide tautomer only. Moreover, the O-bonded DMU ligand is displaced much faster than the N-bonded DMU ligand from platinum by coordinating solvents.

This study was undertaken to evaluate the protective efficacy of the antioxidants vitamin E and Trolox (a water-soluble vitamin E derivative) against the toxicity of microcystin-LR (MC-LR), Microcystis aeruginosa aqueous extract (CE), and a reference toxin, menadione sodium bisulfite (MSB), in Artemia franciscana nauplii. This was achieved by using the well-established brine shrimp bioassay. The experiment was conducted in 2 stages, with (1) 12-h mortality time course and (2) LC50 determination for 12- and 24-h exposures. Treatments consisted of MC-LR, CE, and MSB alone and with 4-h pretreatments of either vitamin E or Trolox. Sensitivity of A. franciscana nauplii with 24-h LC50 values of 11 (10.1-12.1) μg/ml for MSB and 9.5 (8.8-10.4) μg/ml for MC-LR were in general agreement with values reported for Artemia sp. Both antioxidant pretreatments resulted in significant reductions in mortality of approximately 50% at 9 h postexposure when challenged by either 40 μg/ml MC-LR or 20 μg/ml MSB. In contrast, the antioxidant pretreatments offered little to no protection from CE, suggesting that other uncharacterized bioactive compounds contributed to overall toxicity. The described bioassay is easily accessible, inexpensive, rapid, and complies with animal ethics guidelines of many countries, and thus provides a potential alternative to the mouse bioassay for the initial screening for chemoprotectants against MC-LR toxicity. [ABSTRACT FROM AUTHOR]