Structure and anti-metapneumovirus activity of sulfated galactans from the red seaweed Cryptonemia seminervis.

The anti-HMPV (human metapneumovirus) activity was determined for sulfated dl-hybrid galactans obtained from the red seaweed Cryptonemia seminervis and their depolymerized products obtained by reductive partial hydrolysis. Structural studies carried out in three homogeneous depolymerized fractions DS-1, DS-2e and DS-3 (Mw of 51.6-63.8 kDa) showed that these galactans present different chemical characteristics, as monosaccharide composition, content of sulfate groups (14.1-29.9%) and agaran:carrageenan molar ratio diads, 2.7:1 for DS-1 and DS-2e and 1:1 for DS-3. The sulfate groups are located principally on C-2 of ß-d-galactopyranose and 4,6-O-(1'-carboxyethylidene)-ß-d-galactopyranose residues and on C-6 of α-galactose residues. Sulfated dl-galactans and their depolymerized products exhibited antiviral activity at a very early stage of the viral infection cycle. All fractions, except DS-2e inhibited HMPV replication by binding to the viral particle. Besides depolymerized galactans DS-2e and DS-3 inhibited the recognition of cell receptor by HMPV and penetration to the host cell, respectively.

Structural and functional characterization of a multifunctional alanine-rich peptide analogue from Pleuronectes americanus.

Recently, defense peptides that are able to act against several targets have been characterized. The present work focuses on structural and functional evaluation of the peptide analogue Pa-MAP, previously isolated as an antifreeze peptide from Pleuronectes americanus. Pa-MAP showed activities against different targets such as tumoral cells in culture (CACO-2, MCF-7 and HCT-116), bacteria (Escherichia coli ATCC 8739 and Staphylococcus aureus ATCC 25923), viruses (HSV-1 and HSV-2) and fungi (Candida parapsilosis ATCC 22019, Trichophyton mentagrophytes (28d&E) and T. rubrum (327)). This peptide did not show toxicity against mammalian cells such as erythrocytes, Vero and RAW 264.7 cells. Molecular mechanism of action was related to hydrophobic residues, since only the terminal amino group is charged at pH 7 as confirmed by potentiometric titration. In order to shed some light on its structure-function relations, in vitro and in silico assays were carried out using circular dichroism and molecular dynamics. Furthermore, Pa-MAP showed partial unfolding of the peptide changes in a wide pH (3 to 11) and temperature (25 to 95°C) ranges, although it might not reach complete unfolding at 95°C, suggesting a high conformational stability. This peptide also showed a conformational transition with a partial α-helical fold in water and a full α-helical core in SDS and TFE environments. These results were corroborated by spectral data measured at 222 nm and by 50 ns dynamic simulation. In conclusion, data reported here show that Pa-MAP is a potential candidate for drug design against pathogenic microorganisms due to its structural stability and wide activity against a range of targets.

Verbascoside isolated from Lepechinia speciosa has inhibitory activity against HSV-1 and HSV-2 in vitro.

Verbascoside has been isolated form L. speciosa after several different chromatographic methods. After its purification, the structure has been unequivocally established using modern spectroscopic techniques. As for the antiviral activity, the maximum non toxic concentration has been established and this concentration has been used in the anti herpes assay, in vitro. Mechanism of action for this molecule regarding the anti-herpes activity has been studied encompassing the following assays: virucidal activity, cellular receptor assay, penetration assay and intracellular assay, in order to understand the activity for this natural product.

Sulfated fucan from marine alga inhibits HeLa cells infection by HTLV-1 free particles: semi-quantitative analysis

A sulfated fucan from Laminaria abyssalis marine alga prevented the interaction of HTLV-1 particles, purified from the MT-2 cell line, with HeLa cells. The infection obtained using a concentrated virus suspension was detected only by amplification of the newly synthesized HTLV-1 proviral cDNA by the nested-polymerase chain reaction (PCR). The sulfated polysaccharide was not toxic to the cells at a concentration of 100 µg/mL and prevented infection by the viral particles when added to the cell monolayers. The proviral cDNA was only detected when the sulfated polysaccharide was added to the cells three hours post-infection, indicating that the inhibitory activity occurred in the initial stages of virus-cell interaction. Our results demonstrate, for the first time, the ability of a sulfated fucan from marine algae to inhibit virus transmission through free virus particles.

Efeito citotóxico de alginatos odontológicos sobre células fibroblastóides / Cytotoxic effects of a dentstry alginates applied on fibroblast-like cells

O alginato ou hidrocolóide irreversível é um dos materiais de moldagem mais aceitos e utilizados na Odontologia. Algumas substâncias presentes nesses pode levar toxicidade. O estuto foi avaliar a citotoxicidade de alginatos de uso odontológico. Foram avaliados quatro diferentes alginatos divididos em 4 grupos, assim denominados: Ava Gel, New Print, Kromopan e Hydrogum. Três grupos controle também participaram Controle positivo (C+) constituido pelo detergente celular Tween 80, controle negativo (C-) PBS, e controle de célula (CC) onde as células não foram expostas a nenhum material. Após manipulação dos materiais seguindo as orientações do fabricante foi confeccionado corpos de prova utilizando-se anéis de silicone. Em seguida os mesmos foram imersos em meio mínimo essencial de Eagle (MEM) por 2 min, onde então procedeu-se a remoção do sobrenadante e colocação em contato com fibroblastos L929. Após contato com o meio as células foram incubadas por mais 24 h onde então foram adicionados 100ml do corante vermelho neutro a 0,01%. Novamente as células foram incubadas por 3 h para que as mesmas incorporassem o corante. Passado esse período as mesmas foram fixadas e então, realizada contagem de células viáveis em espectrofotômetro (BioTek, Winooski, Vermont, USA) em um comprimento de onda de 492nm. Os resultados demonstraram diferenças estatísticas entre os grupos CC e C-com os demais (P<0.05). Ausência de diferença estatística ocorreu entre os grupos Ava Gel, New Print, Kromopan e Hydrogum (P>0.05). Pode-se concluir com a realização desse trabalho que todos os alginatos testados mostraram caráter citotoxico.

Alginate or irreversible hydrocolloid is one of the most accepted and used impression materials in dentstry. Some substances present in these can lead toxicity. The aim of this study was to evaluate the cytotoxicity of dental alginate of use. Was evaluated four different alginate divided into 4 groups, so called: Ava Gel, New Print, Kromopan e Hydrogum. Three control groups were also included: Group C+ (positive control), consisting of detergent Tween 80; Group C -(negative control), consisting of PBS, and Group CC (cell control), consisting of cells not exposed to any material. After manipulating the materials according to the manufacturer's instructions, samples were made by using silicon rings. Next, the samples were immersed into Eagle minimum essential medium (MEM) for 2 minutes, where the supernatants were removed and brought into direct contact with L929 fibroblasts. Following exposure to the medium, the cells were incubated for further 24 hours and then 100 ml of 0.01% neutral red dye were added. The cells were incubated again for 3 hours so that the dye could be absorbed. After this 3-hour period, the cells were fixed in order to count the viable ones by using a spectrophotometer (BioTek, Winooski, Vermont, USA) at a wavelength of 492nm. The results showed statistical differences between groups CC and C- with the others (P <0.05). Lack of statistical difference occurred between groups and between Ava Gel, New Print, Kromopan e Hydrogum (P> 0.05). Based on the results obtained in this work, one can conclude that all four alginate impression materials are potentially cytotoxic.