RESUMO
Lectins are proteins of nonimmune origin, which are capable of recognizing and binding to glycoconjugate moieties. Some of them can block the interaction of viral glycoproteins to the host cell receptors acting as antiviral agents. Although cyanobacterial lectins have presented broad biotechnological potential, little research has been directed to Amazonian Cyanobacterial diversity. In order to identify new antiviral lectins, we performed genomic analysis in seven cyanobacterial strains from Coleção Amazônica de Cianobactérias e Microalgas (CACIAM). We found 75 unique CDS presenting one or more lectin domains. Since almost all were annotated as hypothetical proteins, we used homology modeling and molecular dynamics simulations to evaluate the structural and functional properties of three CDS that were more similar to known antiviral lectins. Nostoc sp. CACIAM 19 as well as Tolypothrix sp. CACIAM 22 strains presented cyanovirin-N homologues whose function was confirmed by binding free energy calculations. Asn, Glu, Thr, Lys, Leu, and Gly, which were described as binding residues for cyanovirin, were also observed on those structures. As for other known cyanovirins, those residues in both our models also made favorable interactions with dimannose. Finally, Alkalinema sp. CACIAM 70d presented one CDS, which was identified as a seven-bladed beta-propeller structure with binding sites predicted for sialic acid and N-acetylglucosamine. Despite its singular structure, our analysis suggested this molecule as a new putative antiviral lectin. Overall, the identification and the characterization of new lectins and their homologues are a promising area in antiviral research, and Amazonian cyanobacteria present biotechnological potential to be explored in this regard.
Assuntos
Antivirais/química , Proteínas de Bactérias/química , Proteínas de Transporte/química , Cianobactérias/química , Lectinas/química , Genômica , Modelos Moleculares , Simulação de Dinâmica Molecular , Nostoc/química , TermodinâmicaRESUMO
Cyanobacteria are photosynthetic prokaryotes found in a range of environments. They are infamous for the production of toxins, as well as bioactive compounds, which exhibit anticancer, antimicrobial and protease inhibition activities. Cyanobacteria produce a broad range of antifungals belonging to structural classes, such as peptides, polyketides and alkaloids. Here, we tested cyanobacteria from a wide variety of environments for antifungal activity. The potent antifungal macrolide scytophycin was detected in Anabaena sp. HAN21/1, Anabaena cf. cylindrica PH133, Nostoc sp. HAN11/1 and Scytonema sp. HAN3/2. To our knowledge, this is the first description of Anabaena strains that produce scytophycins. We detected antifungal glycolipopeptide hassallidin production in Anabaena spp. BIR JV1 and HAN7/1 and in Nostoc spp. 6sf Calc and CENA 219. These strains were isolated from brackish and freshwater samples collected in Brazil, the Czech Republic and Finland. In addition, three cyanobacterial strains, Fischerella sp. CENA 298, Scytonema hofmanni PCC 7110 and Nostoc sp. N107.3, produced unidentified antifungal compounds that warrant further characterization. Interestingly, all of the strains shown to produce antifungal compounds in this study belong to Nostocales or Stigonematales cyanobacterial orders.
Assuntos
Antifúngicos/isolamento & purificação , Aspergillus flavus/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Cianobactérias/química , Descoberta de Drogas , Anabaena/química , Anabaena/classificação , Anabaena/crescimento & desenvolvimento , Anabaena/isolamento & purificação , Antifúngicos/química , Antifúngicos/farmacologia , Aspergillus flavus/crescimento & desenvolvimento , Brasil , Candida albicans/crescimento & desenvolvimento , Cianobactérias/classificação , Cianobactérias/crescimento & desenvolvimento , Cianobactérias/isolamento & purificação , República Tcheca , Finlândia , Água Doce/microbiologia , Glicolipídeos/química , Glicolipídeos/isolamento & purificação , Glicolipídeos/farmacologia , Lipopeptídeos/química , Lipopeptídeos/isolamento & purificação , Lipopeptídeos/farmacologia , Estrutura Molecular , Tipagem Molecular , Nostoc/química , Nostoc/classificação , Nostoc/crescimento & desenvolvimento , Nostoc/isolamento & purificação , Peptídeos Cíclicos/química , Peptídeos Cíclicos/isolamento & purificação , Peptídeos Cíclicos/farmacologia , Filogenia , Piranos/química , Piranos/isolamento & purificação , Piranos/farmacologia , Águas Salinas , Especificidade da EspécieRESUMO
Objetivo: Determinar la composición química y actividad antioxidante in vitro del extracto acuoso liofilizado de Nostoc sphaericum (cushuro) de la laguna Cushurococha, Junín. Materiales y métodos: Estudio de enfoque cuantitativo; con diseño, descriptivo, observacional, transversal, la muestra biológica fue el extracto acuoso liofilizado de Nostoc sphaericum (cushuro) que se recolectó de la laguna Cushurococha en el departamento de Junín. Se utilizaron los métodos Lowry, Antrona, Folin-Ciocalteu, el ensayo de captación de ABTS+. Resultados: La cantidad, por muestra liofilizada, de proteínas solubles fue de 15.1 mg/g, carbohidratos totales 949ug/g, polifenoles totales 2.98mg EAG/g; así también, el porcentaje de inhibición del radical ABTS+ a una concentración de 0.15mg/mL de muestra liofilizada fue de 52 por ciento, un valor de IC50 entre 10-15 ug/mL y una capacidad antioxidante equivalente a trolox (TEAC-ABTS) igual a 0.384 ugEq. Trolox/ mg extracto de muestra seca. Conclusiones: El extracto acuoso liofilizado de Nostoc sphaericum constituye una buena fuente natural de antioxidantes.
Objective: To determine the chemical composition and in vitro antioxidant activity of lyophilized aqueous extract of Nostoc sphaericum (cushuro) of Cushurococha, Junín lagoon. Materials and Methods: Quantitative research approach; with design, descriptive, observational, cross-sectional, the biological sample was lyophilized aqueous extract of Nostoc sphaericum (cushuro) that was collected from the lagoon Cushurococha in the department of Junín. The method of Lowry, Anthrone, Folin-Cioealteu, assay ABTS+ capture methods were used. Results: The amount, lyophilized sample of soluble proteins was 15.1 mg/g, total carbohydrates 949ug/g, total polyphenols 2.98mg GAE/g; so too, the percentage inhibition of ABTS+ radical at a concentration of 0.15 mg/mL of lyophilized sample was 52 per cent, an IC50 value between 10 to 15 ug/mL and trolox equivalent antioxidant capaeity (TEAC-ABTS) equal to 0.384 ugEq. Trolox/mg dry extract sample. Conclusions: The lyophilized aqueous extract of Nostoc sphaericum is a good natural source of antioxidants.
Assuntos
Antioxidantes , Cianobactérias/química , Liofilização , Nostoc/química , Estudos Observacionais como Assunto , Estudos Transversais , Estudos de Avaliação como AssuntoRESUMO
BACKGROUND: Phycobiliproteins are coloured proteins produced by cyanobacteria, which have several applications because of their colour properties. However, there is no available information about the colour stability of phycobiliproteins from Nostoc sp. in food systems. The aim of this work was to study the colour stability of a purple-coloured phycobiliprotein-rich extract from the cyanobacterium Nostoc PCC9205 in acidic solutions and yogurt. RESULTS: Variations of pH for Nostoc PCC9205 extract have shown stability for the L* (lightness) and a* (redness) indexes in the range 1.0-7.0. The b* index (blueness), however, increased at pH values below 4.0, indicating loss of the blue colour. The Nostoc PCC9205 extract was used as colorant in yogurt (pH 4.17) stored for 60 days. Instrumental colour analysis showed no changes for the L* and a* indexes during storage, whereas the b* index changed after 20 days of storage. A multiple comparison test showed colour instability after 20 days of storage. A hedonic scale test performed on the 60th day of storage showed acceptability of the product. CONCLUSIONS: The red component of the phycobiliprotein-rich extract from Nostoc PCC9205 presented an improved stability in acidic media and yogurt compared with the blue component of this extract.