Photodynamic therapy (PDT) is a minimally invasive approach, in which a photosensitiser compound is activated by exposure to visible light. The activation of the sensitiser drug results in several chemical reactions, such as the production of oxygen reactive species and other reactive molecules, whose presence in the biological site leads to the damage of target cells. Although PDT has been primarily developed to combat cancerous lesions, this therapy can be employed for the treatment of several conditions, including infectious diseases. A wide range of microorganisms, including Gram positive and Gram negative bacteria, viruses, protozoa and fungi have demonstrated susceptibility to antimicrobial photodynamic therapy. This treatment might consist of an alternative to the management of fungal infections. Antifungal photodynamic therapy has been successfully employed against Candida albicans and other Candida species and also against dermatophytes. The strain-dependent antifungal effect and the influence of the biological medium are important issues to be considered. Besides, the choice of photosensitiser to be employed in PDT should consider the characteristics of the fungi and the medium to be treated, as well as the depth of penetration of light into the skin. In the present review, the state-of-the-art of antifungal PDT is discussed and the photosensitiser characteristics are analysed.

Candida yeasts are opportunistic pathogens responsible for infections in immunocompromised individuals. Among the virulence factors present in these yeasts we can mention the ability to adhere to host cells, exoenzyme production and germ tube formation. Several compounds, such as antifungal agents, plants extracts, protein inhibitors and surfactants, have been tested regarding their capacity in inhibit Candida spp. virulence factors. Among these compounds, a significant lower number of works are focused on the inhibition action caused by different types of surfactant. The present work aimed to evaluate the effect generated by the surfactants cetyltrimethylammonium chloride (CTAC), sodium dodecyl sulfate (SDS), N-hexadecyl-N-N'-dimethyl-3-ammonio-1-propane-sulfonate (HPS) and octylphenoxypolyethoxyethanol (Triton X-100) on the viability, adhesion ability and exoenzyme production by Candida species. CTAC and HPS were capable to inhibit Candida spp. growth at very low concentrations. All surfactants demonstrated to be capable to inhibit the adhesion of Candida species to buccal epithelial cells (BEC) and the proteinase production. On the other hand, the phospholipase production remained unaltered after the treatment with these compounds. The present data denote that cationic and zwitterionic surfactants are interesting prototypes of inhibitory agents against Candida spp., which is probably associated with the cationic punctual charge of both surfactants. The results are discussed in details in agreement with recent reports from literature.

We study the resonant scattering of light by a transparent dielectric spheroid. We try to understand the features of the resonant modes of a spheroidal optical cavity. In this way, we use an analogy between optics and quantum mechanics. Through this analogy it is possible to interpret resonances as quasibound states of light. Using semiclassical methods such as the WKB method and a uniform asymptotic expansion for spheroidal radial functions, we developed algorithms that permit us to calculate the resonance position as well as the resonance width.

In this paper we deal with the problem of controlling some Chaplygin systems in the framework of the vakonomic approach for nonholonomic systems. Equations of motion for these systems are obtained which contain a free parameter that permits to control the system. It is show that given a prescribed path it is possible to determine the parameter of control which inserted in the equations of motion compel the trajectory of the system to follow the input function.

Recebido em 26/1/10; aceito em 1/6/10; publicado na web em 22/9/10 GIANT EXTRACELLULAR HEMOGLOBIN OF Glossoscolex paulistus: AN EXTRAORDINARY SUPRAMOLECULAR HEMOPROTEIN SYSTEM. Giant extracellular hemoglobins are considered the summit of complexity in systems that carry oxygen, constituting an extraordinary model system to the study of hemoproteins. This class includes the hemoglobin of the annelid Glossoscolex paulistus that presents high cooperativity, great oligomeric and redox stabilities and ability of oligomeric reassociation. These properties have motivated evaluations about its utilization as prototype of artificial blood and biosensor. Kinetic studies involving autoxidation and detailed spectroscopic characterizations of its ferrous and ferric species have propitiated information about the structure-activity relationship of this macromolecule. The present review analyzes several biochemical issues, evaluating the state-of-art of this subject.Keywords: hemoglobin; ligand exchange; autoxidation. INTRODUÇÃOA hemoglobina extracelular gigante de Glossoscolex paulistus (HbGp) é uma hemoproteína que constitui um sistema carregador de oxigênio in vivo e, consequentemente, credenciado pela seleção natural, apresentando características extremamente interessantes em termos de evolução como, por exemplo, sua possível adaptação a meios ricos em sulfetos.1 Esta hemeproteína apresenta uma extraordinária massa molecular, em torno de 3,1 MDa, 2 com uma unidade estrutural básica altamente organizada, contendo 144 cadeias que apresentam o grupo heme, além da presença de aproximadamente 36 cadeias que não apresentam este grupamento prostético.Os sistemas hemoglobínicos gigantes extracelulares, também conhecidos por eritrocruorinas, 3 constituem arranjos supramoleculares proteicos tão elaborados do ponto de vista da sua relação estrutura/ atividade, que são considerados, segundo Vinogradov, 4,5 o ápice de complexidade em se tratando de hemoproteínas que ligam oxigênio.Além disso, este grupo de hemoglobinas é conhecido por ligações de oxigênio altamente cooperativas.6-8 Entre elas, destaca-se a hemoglobina de Lumbricus terrestris, que vem sendo amplamente estudada por diversos grupos e que apresenta similaridade macromolecular com a hemoglobina de Glossoscolex paulistus. Cálculos por homologia envolvendo o monômero d de Glossoscolex paulistus constataram uma identidade estrutural de 54% em relação ao monômero d de Lumbricus terrestris.A título de ilustração, é interessante mencionar que a hemoglobina de Lumbricus terrestris vem sendo aplicada em pesquisas sobre sangue artifical, 7,9,10 devido à sua natureza extracelular, grande tamanho e resistência à oxidação. Em relação a este último tópico, vale citar os trabalhos de Dorman e colaboradores 9 e Madura e colaboradores 8 que, por meio de estudos espectroeletroquímicos, têm determinado que a hemoglobina de Lumbricus terrestris exibe potenciais redox altamente positivos (de +112 até +61 mV) quando comparados aos potenciais negativos das hemoglobinas tetraméricas e mioglobinas ...