(2012)

allowed detection and confirmation of an array of microcystins in a difficult matrix from a natural cyanobacterial bloom. Application of thiol derivatization methods lead to identification of MC-RY and related analogues in samples from Lake Victoria, and to the eventual isolation and structure confirmation of MC-RY (9) by NMR spectroscopy. MC-RY and its analogues have now been reported from Uganda (Okello et al., 2010a), Kenya (Miles et al., 2012), and Tanzania (present study), suggesting that this type of analogue may be relatively common in Africa. No ethical issues identified. We thank Silvio Uhlig and Wolfgang Egge-Jacobsen for assistance with LC–HRMS, IMB

NRC, Halifax, NS, Canada for NMR-quantitated cyanotoxin standards, Jonathan Puddick for helpful discussions, MDV3100 Vincristine in vivo and Kathryn L. Miles for assistance with preparation of Figures. This study was supported by grant 196085/V10 (Monitoring of Cyanotoxins in Southern Africa) from The Research Council of Norway, and by The Norwegian Programme for Development, Research and Higher Education (NUFU PRO 07/10224) and SIDA SAREC: VICRES Endocrine disruptors project (SUA). The Bruker AV II 600 instrument and its TCI cryoprobe were fully financed by The Research Council of Norway. “
“Loxoscelism is the most important clinical syndrome resulting from Loxosceles spp spider bite and follows two well-defined clinical variants:

the cutaneous form which manifests as erythema and edema that may develop into necrotic ulcer, whilst systemic loxoscelism is characterized by intravascular hemolysis and occasional renal failure ( da Silva et al., 2004; Ministério da Saúde, 2011). Loxosceles laeta (Nicolet, 1849) (Araneae, Sicariidae), known as “brown spider”, “corner spider” and “spider violin”, is an endemic species of South America, which has been introduced 3-mercaptopyruvate sulfurtransferase into the East of this continent and also into both North and Central America ( Gerstch, 1967). L. laeta species is found throughout Argentina ( de Roodt et al., 2002), frequently reported in the South region of Brazil ( Malaque et al., 2002), widely distributed in Chile ( Manriquez and Silva, 2009) and also found throughout the Peruvian territory, where it is also named “killer spider”, due to the association of this spider with many fatal cases of loxoscelism ( Maguiña-Vargas et al., 2004). Loxoscelism is a serious public health problem in Peru, the number of human accidents caused by spiders of Loxosceles genus attains 2500 per year ( Panaftosa, 2007). L. Laeta and in a lesser extent Loxosceles rufipes are the most medically relevant species in Peru ( Sanabria and Zavaleta, 1997). The highest incidence of envenomations is recorded in cities along the Peruvian Coast ( Sanabria and Zavaleta, 1997).