The SARS-CoV-2 entry into host cells is mainly mediated by the interactions between the viral spike protein (S) and the ACE-2 cell receptor, which are highly glycosylated. Therefore, carbohydrate binding agents may represent potential candidates to abrogate virus infection. Here, we evaluated the in vitro anti-SARS-CoV-2 activity of two mannose-binding lectins isolated from the Brazilian plants Canavalia brasiliensis and Dioclea violacea (ConBR and DVL). These lectins inhibited SARS-CoV-2 Wuhan-Hu-1 strain and variants Gamma and Omicron infections, with selectivity indexes (SI) of 7, 1.7, and 6.5, respectively for ConBR; and 25, 16.8, and 22.3, for DVL. ConBR and DVL inhibited over 95% of the early stages of the viral infection, with strong virucidal effect, and also protected cells from infection and presented post-entry inhibition. The presence of mannose resulted in the complete lack of anti-SARS-CoV-2 activity by ConBR and DVL, recovering virus titers. ATR-FTIR, molecular docking, and dynamic simulation between SARS-CoV-2 S and either lectins indicated molecular interactions with predicted binding energies of −85.4 and −72.0 Kcal/Mol, respectively. Our findings show that ConBR and DVL lectins possess strong activities against SARS-CoV-2, potentially by interacting with glycans and blocking virus entry into cells, representing potential candidates for the development of novel antiviral drugs.

Cryptococcus neoformans is the pathogen responsible for cryptococcal pneumonia and meningitis, mainly affecting patients with suppressed immune systems. We have previously revealed the mechanism of anticryptococcal action of synthetic antimicrobial peptides (SAMPs). In this study, computational and experimental analyses provide new insights into the mechanisms of action of SAMPs. Computational analysis revealed that peptides interacted with the PHO36 membrane receptor of C. neoformans. Additionally, ROS (reactive oxygen species) overproduction, the enzymes of ROS metabolism, interference in the ergosterol biosynthesis pathway, and decoupling of cytochrome c mitochondrial membrane were evaluated. Three of four peptides were able to interact with the PHO36 receptor, altering its function and leading to ROS overproduction. SAMPs-treated C. neoformans cells showed a decrease in scavenger enzyme activity, supporting ROS accumulation. In the presence of ascorbic acid, an antioxidant agent, SAMPs did not induce ROS accumulation in C. neoformans cells. Interestingly, two SAMPs maintained inhibitory activity and membrane pore formation in C. neoformans cells by a ROS-independent mechanism. Yet, the ergosterol biosynthesis and lactate dehydrogenase activity were affected by SAMPs. In addition, we noticed decoupling of Cyt c from the mitochondria, which led to apoptosis events in the cryptococcal cells. The results presented herein suggest multiple mechanisms imposed by SAMPs against C. neoformans interfering in the development of resistance, thus revealing the potential of SAMPs in treating infections caused by C. neoformans.

Multiresistant pathogens pose a serious threat to human health. The genus Candida is one class of human pathogenic yeasts responsible for infections affecting healthy and immunocompromised patients. In this context, plant essential oils emerged as a future natural alternative to control the diseases caused by these pathogens. Based on that, the present study aimed to evaluate the antimicrobial potential of essential oil from C. pluriglandulosus and understand the mechanism of action. Here, it highlighted antimicrobial activity and the mechanisms of action of the essential oil extracted from C. pluriglandulosus Carn.-Torres & Riina (CpEO) leaves on human pathogenic microorganisms in planktonic and biofilm lifestyles. In addition, for the first time, the oil composition was revealed by GC-MS analysis and the toxicity to human red blood cells (HRBC). Twenty-six chemical compounds were identified in CpEO, elemicin, bicyclogermacrene, caryophyllene, brevifolin, and 2,4,6-trimethoxy-styrene. Through hemolytic assay, it was shown that CpEO has no toxicity to human RBCs. At the concentration of 50 μg mL⁻¹, CpEO did not show great antibacterial potential. However, promising data were found for C. krusei and C. parapsilosis inhibiting by 89.3% and 80.7% of planktonic cell growth and 83.5% and 77.9% the biofilm formation, respectively. Furthermore, the mechanisms of action CpEO were elucidated by fluorescence. Scanning electron microscopy revealed damage to the cell membrane and pore formation, ROS overproduction, and induction of apoptosis in candida cells. Our results reinforce the potential of CpEO as an effective alternative molecule of pharmaceutical interest.

A aquaponia é uma modalidade de produção de alimentos que integra a aquicultura e a hidroponia num sistema fechado de recirculação de água e nutrientes. Esta atividade é uma alternativa viável para a produção sustentável de alimentos onde o abastecimento de água é mínimo, tornando seu uso mais eficiente por pequenos produtores ou em regiões com déficit de uso da água. Este estudo avaliou o crescimento do tambaqui (Colossoma macropomum) associado à hidroponia durante um período de 110 dias, quanto ao ganho de peso, a conversão alimentar e a sobrevivência dos peixes, os quais apresentaram comprimento e peso final de 15,5 ± 1,09 cm e 67,78 ± 13,86 g, respectivamente, na densidade de 50 peixes m-³. O consumo de ração total foi de 7,0 kg, a conversão alimentar foi de 1,8 e a biomassa final foi de 3,86 kg m-³. A sobrevivência foi de 100%. A qualidade da água se manteve ideal para o desenvolvimento do tambaqui. Em relação à planta, no período de 40 dias, a quantidade de nutrientes produzidos a partir dos resíduos da água de criação na fase de alevinagem não foi satisfatória para o desenvolvimento da alface. Conclui-se que o sistema de aquaponia pode assegurar um desenvolvimento sustentável na criação do tambaqui nas fases de alevinagem e recria em relação à qualidade da água e desempenho, entretanto, em relação à alface um maior aporte de nutrientes deverá ser suplementado para assegurar um bom desenvolvimento das plantas.

In a quantitative field research, the objective of this work was to determine the best stocking density for tambatinga juveniles (Colossoma macropomum × Piaractus brachypomus) in a recirculation system during 50 days of cultivation. Tambatinga juveniles (0.72±0.02 g) were distributed in 0.08 m3 polyethylene boxes with densities of 5, 10 and 15 fish/box, with five replicates per treatment. During the experimental period, water quality, weight gain, apparent feed conversion, specific growth rate, carcass yield, proximate composition and final survival were evaluated. The water parameters remained stable and in the desired range for the species during the experimental period (temperature 25±1.52° C, pH 5.85±0.7 and dissolved oxygen 6.51±0.05 mg L-1). Statistical analyzes showed no significant difference for apparent feed conversion and survival rate. The lowest stocking density (5 fish/box) showed greater weight gain and specific growth rate, while the density of 10 fish/box showed high lipid deposition in the carcass. Aiming at greater weight gain and better specific growth rate, the results indicated that the density of 5 fish/box (0.08 m3), is the most suitable for juveniles of this species.