RESUMO
A family of 4kDa neurotoxic peptides was purified from venoms of Phoneutria spiders. All have six cysteine residues, and low similarity with other neurotoxins. Three toxins caused moderate inhibition of L-type Ca(2+) channels. The structure of toxin PRTx27C3 was modeled and compared with toxin ADO1. The importance of four residues is suggested.
Assuntos
Neurotoxinas/química , Venenos de Aranha/química , Aranhas/química , Sequência de Aminoácidos , Animais , Bloqueadores dos Canais de Cálcio/química , Bloqueadores dos Canais de Cálcio/isolamento & purificação , Bloqueadores dos Canais de Cálcio/toxicidade , Canais de Cálcio Tipo L/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Cromatografia por Troca Iônica , Camundongos , Modelos Moleculares , Dados de Sequência Molecular , Peso Molecular , Neurotoxinas/genética , Neurotoxinas/isolamento & purificação , Neurotoxinas/toxicidade , Conformação Proteica , Homologia de Sequência de Aminoácidos , Espectrometria de Massas por Ionização por Electrospray , Venenos de Aranha/genética , Venenos de Aranha/isolamento & purificação , Venenos de Aranha/toxicidade , Aranhas/genéticaRESUMO
Multiple shoots were differentiated in cotyledonary nodes of 10 d old seedlings of Melissa officinalis, cultured on MS medium supplemented with BAP (0-4 mg/l). The production of shoots was further induced in subcultures of the original expiant, after the first harvest of shoots (stump), using similar conditions. The highest average number of shoots in the two inoculations was obtained with 2 mg/l of BAP: 24 axillary shoots per explant, 7 in the first inoculation and 17 in the second one. The maximum elongation of shoots was achieved with BAP at 0.2 mg/l, and higher concentrations of the hormone induced a decrease in their size. A range of BAP concentrations between 0.2-0.5 mg/l allowed the production of more shoots with a size suitable for rooting. Roots were induced in 30 d old shoots, transferred to MS medium individually supplemented with IBA or NAA (0-4 mg/l). Micropropagated plants were successfully transferred to soil.