Skin lesions simulating blue toe syndrome caused by prolonged contact with a millipede

Venomous animals are those that, by means of a hunting and defense mechanism, are able to inject their prey with a toxic substance produced in their bodies, directly from specialized glands (e.g., tooth, sting, spur) through which the poison passes. Millipedes are poisonous animals; they can be harmful to humans, and their effects usually manifest as erythematous, purpuric, and cyanotic lesions; local pain; and paresthesia. Here, we report a case of skin contact with a millipede for 6h resulting in skin lesions similar to blue toe syndrome.

Concentración natural de compuestos antimaláricos en artrópodos tropicales (in vitro)

Natural concentration of antimalaric components in Tropical arthropods (in vitro). Alcohol, hexane and dichlorometane extracts of 751 samples of Costa Rican arthropods were studied for the presence of antimalaric components. With Plasmodium berghei we set an in vitro model in which the effect of the extract was determined by staining of the parasites with cresil brilliant blue. Active extracts at concentration of 50 mg or less, were considered positive. Promissory extracts were found in the orders Lepidoptera (24.1%), Coleoptera (32.8%), Hemiptera (38.5%) and Polydesmida (81.3%). Since most of the Lepidoptera samples were in the immature stages, the relation with the host plant was analyzed. Cannaceae, Flacourtiaceae, Crisobalanaceae, Lauraceae, Fagaceae, Ulmaceae, Rosaceae, Asteraceae, Rubiaceae, Lauraceae and Caprifoliaceae were related with the Lepidoptera larvae, and an antimalaric effect has been reported in most of these families. In the orders Polydesmida, Opiliones and Blattodea, the extract from adults also had some important effect, probably because all of them fed on plants. Polydesmida and Opiliones have chemical substances that probably serve as defensive purposes; these chemicals could also have some antiparasitic effect. Therefore, the detection of antimalaric components in arthropod species led to the identification of plants with promissory antimalaric components. Rev. Biol. Trop. 56 (2): 473-485. Epub 2008 June 30.

Extractos alcohólicos, hexánicos y diclorometánicos de 751 muestras de artrópodos fueron estudiados por la presencia de actividad antimalárica. En este trabajo se empleó un modelo murino usando el Plasmodium berghei, modelo que es biológicamente similar a la malaria humana. El estudio fue realizado determinando el efecto del extracto sobre el parásito por la inclusión o no del colorante azul de cresil brillante. Estimando como positivos aquellos extractos cuya actividad antimalárica se mostró en concentraciones no mayores de 50 mg, se encontró que los órdenes más promisorios fueron Lepidoptera (24.1%), Polydesmida (81.3%), Blattodea (25%) y Opiliones, entre otros. Las formas inmaduras de Lepidoptera fueron las más positivas, por lo que se analizaron las plantas hospederos de donde se alimentaban dichos organismos. Las familias de estas plantas eran Malvaceae, Acanthaceae, Rutaceae, Myrtaceae, Solanaceae, Fabaceae, Urticaceae, Anacardiaceae, Rosaceae, Asteraceae, Rubiaceae, Lauraceae y Caprifoliaceae. Especies de casi todas estas familias han sido reportadas con actividad antimalárica. En el caso de los órdenes Polydesmida, Opiliones y Blattodea, cuyas formas adultas presentaron alguna actividad contra P. berghei, encontramos que todos esos grupos se alimentan también de plantas. En el caso de Opiliones sus especies son predadores de lepidópteros, coleópteros, hemípteros fitófagos y otros artrópodos, además de que producen sustancias de defensas tales como alcoholes, cetonas y quinonas, entre otros, todo lo cual podría explicar la actividad encontrada. Algunas especies del Orden Polydesmida, también secretan ciertas sustancias químicas, las cuales podrían tener un efecto antiparasitario. Así, a través de este trabajo en artrópodos hemos llegado a identificar fuentes vegetales potenciales para componentes antimaláricos.

Induction, purification and characterization of an antibacterial peptide scolopendrin I from the venom of centipede Scolopendra subspinipes mutilans.

The crude venom of the centipede Scolopendra subspinipes mutilans, injected with Escherichia coli K12D31 for 3-4 days showed broad-spectrum antimicrobial activity against Gram-positive. Gram-negative bacteria and fungi. It showed good antibacterial activity against E. coli K12D31 at different temperatures, pH, and ionic strengths. The crude venom was heated at 100 degrees C for 30 min, centrifuged at 10,000 rpm for 30 min at 4 degrees C and the supernatants were obtained, from which an antibacterial fraction having a molecular mass of 3000-5000 Da, was further separated by ultrafiltration. A homogeneous antibacterial peptide named scolopendrin I, having a molecular mass of 4,498 Da, was isolated using cation-exchange chromatography and two steps of reverse-phase high performance liquid chromatography (RP-HPLC). Scolopendrin I did not show any hemolytic and agglutination activities at the concentration below 30 microM.