No abstract

This study evaluated the antimicrobial effect of 3β,6β,16β-trihydroxylup-20(29)-ene (CLF1), a triterpene isolated from Combretum leprosum Mart., in inhibiting the planktonic growth and biofilms of Gram positive bacteria Streptococcus mutans and S. mitis. The antimicrobial activity was assessed by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The antibiofilm potential was determined by quantifying total biomass and enumerating biofilm-entrapped viable bacteria. In addition, the acute toxicity of CLF1 on Artemia sp. nauplii was also determined. The results showed that CLF1 was able in inhibiting the growth of S. mutans and S. mitis with MIC and MBC of 7.8 μg/mL and 15.6 μg/mL, respectively. CLF1 was highly effective on biofilms of both bacteria. Only 7.8 μg/mL CLF1 was enough to inhibit by 97% and 90% biomass production of S. mutans and S. mitis, respectively. On the other hand, such effects were not evident on Gram negative Pseudomonas aeruginosa and Klebsiella oxytoca. The toxicity tests showed that the LC50 of CLF1 was 98.19 μg/mL. Therefore, CLF1 isolated from C. leprosum may constitute an important natural agent for the development of new therapies for caries and other infectious diseases caused by S. mutans and S. mitis.

No abstract

The apoptotic effect of H3 may be related to a balance between apoptotic and autophagic cell death, mediated by increased expression of CASP 9 and LC3-II. To the best of our knowledge this is the first report about a sponge lectin triggering both apoptosis and autophagy in MCF7 cell.

A new lectin from the marine sponge Chondrilla caribensis (CCL) was isolated by affinity chromatography in Sepharose 6B media. CCL is a homotetrameric protein formed by subunits of 15,445 ±2Da. The lectin showed affinity for disaccharides containing galactose and mucin. Mass spectrometric analysis revealed about 50% of amino acid sequence of CCL, which showed similarity with a lectin isolated from Aplysina lactuca. Secondary structure consisted of 10% α-helix, 74% β-sheet/β-turn and 16% coil, and this profile was unaltered in a broad range of pH and temperatures. CCL agglutinated Staphylococcus aureus, S epidermidis and Escherichia coli, and it was able to reduce biofilm biomass, but showed no inhibition of planktonic growth of these bacteria. CCL activity was inhibited by α-lactose, indicating that Carbohydrate Recognition Domain (CRD) of the lectin was involved in antibiofilm activity.