Chlorella vulgaris extract and Imiquimod as new therapeutic targets for leishmaniasis: An immunological approach.

The therapeutic regimen for the treatment of American Tegumentary Leishmaniasis (ATL) is targeted at the death of the parasite; therefore, it is essential to develop a treatment that can act on the parasite, combined with the modulation of the inflammatory profile. Thus, the aim of this study was to make an in vitro evaluation of the therapeutic potential of Chlorella vulgaris extract (CV) and Imiquimod for ATL. Selectivity indices (SI) were determined by inhibitory concentration assays (IC50) in L. braziliensis cells and cytotoxic concentrations (CC50) were measured in human cells using the MTT method, based on the CV microalgae extract (IC50 concentrations of 15.63 to 500 µg/mL; CC50 concentrations of 62.5-1000 µg/mL) in comparison with the reference drugs and Imiquimod. The immune response was evaluated in healthy human cells by gene expression (RT-qPCR) and cytokine production (Flow Cytometry). The CV extract (SI = 6.89) indicated promising results by showing higher SI than meglumine antimoniate (SI = 3.44) (reference drug). In all analyses, CV presented a protective profile by stimulating the production of Th1 profile cytokines to a larger extent than the reference drugs. Imiquimod showed a high expression for Tbx21, GATA3, RORc and Foxp3 genes, with increased production only of the TNF cytokine. Therefore, the data highlight the natural extract and Imiquimod as strong therapeutic or adjuvant candidates against ATL, owing to modulation of immune response profiles, low toxicity in human cells and toxic action on the parasite.

Microalgal production under mixotrophic conditions using cheese whey as substrate

Microalgae are known for producing various biotechnological products. Moreover, they absorb nutrients from dairy wastewater, grow well, and accumulate valuable compounds faster. In this study, photoautotrophic and mixotrophic cultivation with different initial lactose concentrations present in cheese whey (CW) were established to investigate their effect on cell concentration (Xm, mg L-1), cell productivity (Px, mg L-1day-1), and specific cell growth (µmax, day-1) of Chlorella vulgaris, Dunaliella tertiolecta,and Tetradesmus obliquus. The biomass production of C. vulgaris(Xm= 1,520 ± 30.3 mg L-1, Px = 147 ± 3.00 mg L-1, and µmax= 0.150 ± 0.00 mg L-1) in mixotrophic culture with 10.0 g L-1 of lactose, the main constituent of CW, was notably enhanced by 55% in comparison with their photoautotrophic cultures, whereas a lower effect of these lactose concentrations on cell growth was observed in T. obliquus and D. tertiolecta. Thus, mixotrophic cultivation of C. vulgarisusing CW as a carbon and energy source could be considered a feasible alternative to obtain high value-added biomass.(AU)

Chlorella vulgaris mixotrophic growth enhanced biomass productivity and reduced toxicity from agro-industrial by-products.

Algal wastewater remediation has become attractive for a couple of years now, however the effectiveness of genetic toxicity reducing of some by-products through microalgae are still not well reported. This study aimed to evaluate the growth, nutrients and toxicity removal of Chlorella vulgaris cultivated under autotrophic and mixotrophic conditions in three agro-industrial by-products. Mixotrophic culture using corn steep liquor showed higher cell concentration, specific growth rate, maximum cell productivity and biomass protein content when compared to cheese whey and vinasse. Nutrient removal results showed that C. vulgaris was able to completely remove corn steep liquor nutrients, while in cheese whey and vinasse culture this removal was not as efficient, observing remaining COD. This work evaluated for the first time the corn steep liquor and cheese whey genetic toxicity through Allium cepa seeds assay. These results demonstrate that corn steep liquor toxicity was totally eliminated by C. vulgaris cultivation, and cheese whey and vinasse toxicity were minimized. This study proves that the mixotrophic cultivation of C. vulgaris can increase cellular productivity, as well as it is a suitable and economic alternative to remove the toxicity from agroindustrial by-products.