The emission of light by living organisms, bioluminescence, has been studied since the nineteenth century. However, some bioluminescent systems, such as fungi, remain poorly understood. The emitter, the two enzymes involved, and the reaction mechanism have not yet been unraveled. Moreover, the ecological role and evolutionary significance for fungal luminescence is also unknown. It is hoped that comprehensive research on fungal bioluminescent systems will generate knowledge and tools for academic and applied sciences. This review discusses the distribution of bioluminescent fungi on Earth, attempts to elucidate the mechanism involved in light emission, and presents preliminary results on the evolution and ecological role of fungal bioluminescence.

A influência da microestrutura e da composição da camada superficial na transpassivação de fios de NiTi utilizados em implantes endovasculares não tratados e tratados termicamente (500 ºC) foi estudada por métodos eletroquímicos (potencial de circuito aberto e curvas de polarização potenciodinâmica), difração de raios-X (DRX) e microscopia eletrônica de varredura (MEV). O potencial no qual o filme passivo rompe-se (Eb) depende da composição química da camada de óxidos que recobre o eletrodo, assim como da microestrutura do biomaterial. Para as amostras de NiTi não tratadas termicamente, a microestrutura é mais desordenada, porém altamente resistente à transpassivação (Eb ~ 1,00 V/ECS). Entretanto, a presença de um filme nativo rico em oxigênio facilita a sua dissolução (Eb ~ 0,00 V/ECS). Quando tratado termicamente, o biomaterial NiTi torna-se estruturalmente mais ordenado, todavia menos resistente à dissolução (Eb ~ 0,12 V/ECS), sendo que a presença do filme nativo e rico em oxigênio tem pouca influência no valor de Eb (Eb ~ 0,03 V/ECS) neste caso.

The microstructure and surface composition effects on the transpassivation behavior of untreated and heat treated at 500 ºC NiTi wires used for implant purposes were investigated by electrochemical techniques (open circuit potential and potentiodynamic polarization curves), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The potential at which the passive film breaks down (Eb) (transpassivation) was found to be strictly dependent on both the chemical composition of oxide covering layer and the microstructure of the biomaterial. It could be concluded that the disordered microstructure of untreated NiTi is highly resistant to transpassivation (Eb ~ 1.00 V/SCE), but the presence of a native oxygen rich oxide film onto it makes the dissolution easier (Eb ~ 0.00 V/SCE). Upon thermally treating, the microstructure becomes ordered and less resistant to dissolution (Eb ~ 0.12 V/SCE), but in this case the presence of an oxygen rich native film influenced Eb in a lower extent (Eb ~ 0.03 V/SCE).