RESUMEN

Arid-land plants from the Cactaceae family are endemic to the Americas and cultivated worldwide. Cactaceous plants and their fruits contain phenolic compounds, betalains, vitamins, carotenoids, minerals, and soluble fiber. Edible cactaceous matrices can be considered functional foods since their consumption may confer health benefits. These plants could be a source of novel bioactive compounds relevant to the area of phytomedicine. However, consumption of high concentrations of active molecules is not necessarily correlated to beneficial physiological effects because phytochemicals must be released from the food matrices under physiological conditions, resist digestion-associated chemical transformations, and remain in their active state in systemic circulation until the target tissues are reached. Notably, although digestion may either increase or decrease the bioactive phytochemicals' activity and stability, non-absorbed compounds may also be relevant for human health. Additionally, food matrices' type and composition and their technological processing operations may influence the compounds' release, stability, and accessibility. Thus, this review provides insights on the feasibility of using Cactaceae plants as sources of functional compounds. It is focused on compounds' bioactivity, bioaccessibility, and overall bioavailability after their metabolic transformation. Also, it addresses the influence of food processing on bioactive compounds. Many Cactaceae species are unexplored, and our understanding of how they confer health benefits is limited. To better understand the physiological relevance, nutraceutical potential, and therapeutic feasibility of cactaceous bioactive phytochemicals, future research should focus on the metabolic stability and safety of these compounds, as well as their assimilation mechanisms (absorption, distribution, and metabolic fate).

Asunto(s)

Cactaceae , Betalaínas , Cactaceae/química , Carotenoides , Humanos , Minerales , Fitoquímicos/química , Vitaminas

RESUMEN

Prohibitin (PHB) is a highly conserved eukaryotic protein complex involved in multiple cellular processes. In insects, PHB has been identified as a potential target protein to insecticidal molecules acting as a receptor of PF2 insecticidal lectin in the midgut of Zabrotes subfasciatus larvae (bean pest) and Cry protein of Bacillus thuringiensis in Leptinotarsa decemlineata (Colorado potato beetle). This study aimed to characterize the structural features of Z. subfasciatus prohibitin (ZsPHB) by homology modeling and evaluate its expression and tissue localization at different stages of larval development both at the transcript and protein levels. The samples were collected from eggs and larvae of different developmental stages. The immunodetection of ZsPHB was done with anti-PHB1 and confirmed by LC-MS/MS analysis. Gene expression analysis of ZsPHB1 and ZsPHB2 was performed by RT-qPCR, and immunohistochemistry with FITC-labeled anti-PHB1. Results showed that ZsPHBs exhibit distinctive characteristics of the SPFH protein superfamily. The transcript levels suggest a coordinated expression of ZsPHB1 and ZsPHB2 genes, while ZsPHB1 was detected in soluble protein extracts depending on the stage of development. Histological examination showed ZsPHB1 is present in all larval tissues, with an intense fluorescence signal observed at the gut. These results suggest a physiologically important role of PHB during Z. subfasciatus development and show its regulation occurs at the transcriptional and post-transcriptional levels. This is the first characterization of PHB in Z. subfasciatus.

Asunto(s)

Escarabajos , Fabaceae , Gorgojos , Animales , Cromatografía Liquida , Escarabajos/genética , Larva/metabolismo , Prohibitinas , Espectrometría de Masas en Tándem , Gorgojos/genética

RESUMEN

In Mexico, the mango crop is affected by anthracnose caused by Colletotrichum species. In the search for environmentally friendly fungicides, chitosan has shown antifungal activity. Therefore, fungal isolates were obtained from plant tissue with anthracnose symptoms from the state of Guerrero in Mexico and identified with the ITS and ß-Tub2 genetic markers. Isolates of the Colletotrichum gloeosporioides complex were again identified with the markers ITS, Act, ß-Tub2, GADPH, CHS-1, CaM, and ApMat. Commercial chitosan (Aldrich, lot # STBF3282V) was characterized, and its antifungal activity was evaluated on the radial growth of the fungal isolates. The isolated anthracnose-causing species were C. chrysophilum, C. fructicola, C. siamense, and C. musae. Other fungi found were Alternaria sp., Alternaria tenuissima, Fusarium sp., Pestalotiopsis sp., Curvularia lunata, Diaporthe pseudomangiferae, and Epicoccum nigrum. Chitosan showed 78% deacetylation degree and a molecular weight of 32 kDa. Most of the Colletotrichum species and the other identified fungi were susceptible to 1 g L-1 chitosan. However, two C. fructicola isolates were less susceptible to chitosan. Although chitosan has antifungal activity, the interactions between species of the Colletotrichum gloeosporioides complex and their effect on chitosan susceptibility should be studied based on genomic changes with molecular evidence.

Asunto(s)

Antifúngicos/farmacología , Quitosano/farmacología , Colletotrichum , Mangifera/microbiología , Colletotrichum/clasificación , Colletotrichum/crecimiento & desarrollo , Colletotrichum/aislamiento & purificación

RESUMEN

Wheat is a highly relevant crop worldwide, and like other massive crops, it is susceptible to foliar diseases, which can cause devastating losses. The current strategies to counteract wheat diseases include global monitoring of pathogens, developing resistant genetic varieties, and agrochemical applications upon diseases' appearance. However, the suitability of these strategies is far from permanent, so other alternatives based on the stimulation of the plants' systemic responses are being explored. Plants' defense mechanisms can be elicited in response to the perception of molecules mimicking the signals triggered upon the attack of phytopathogens, such as the release of plant and fungal cell wall-derived oligomers, including pectin and chitin derivatives, respectively. Among the most studied cell wall-derived bioelicitors, oligogalacturonides and oligochitosans have received considerable attention in recent years due to their ability to trigger defense responses and enhance the synthesis of antipathogenic compounds in plants. Particularly, in wheat, the application of bioelicitors induces lignification and accumulation of polyphenolic compounds and increases the gene expression of pathogenesis-related proteins, which together reduce the severity of fungal infections. Therefore, exploring the use of cell wall-derived elicitors, known as oligosaccharins, stands as an attractive option for the management of crop diseases by improving plant readiness for responding promptly to potential infections. This review explores the potential of plant- and fungal-derived oligosaccharins as a practical means to be implemented in wheat crops.

RESUMEN

BACKGROUND: The postharvest application of pectic-oligosaccharides (POS) as an elicitor to improve the postharvest shelf-life and nutritional quality by stimulating natural defense mechanisms in strawberries was studied. Strawberries (cv. Festival) were treated with POS (at 0, 2, 5, and 9 g L-1 ) and evaluated for firmness, weight loss, color, soluble solids, titratable acidity (TA), total phenolic and anthocyanin content, antioxidant capacity, decay, and some defense-related enzyme activity during storage at 2 ± 0.5 °C for 14 days. RESULTS: Treatment with POS significantly delayed (P < 0.05) strawberry decay, and reduced the water loss and softening of fruit during storage. Strawberries treated with POS showed a significant increase in total phenolic and anthocyanin content, and antioxidant capacity when compared with controls. Interestingly, POS induced higher activity of phenylalanine ammonia-lyase (PAL), chitinase, and ß-1,3-glucanase in strawberries. Compared to the control, the activity of enzymes was markedly increased in fruit treated with all tested POS concentrations, particularly chitinase, and ß-1,3-glucanase activities, but 5 and 9 g L-1 POS were the most effective treatments for maintaining the quality attributes and improving anthocyanin accumulation and antioxidant capacity of strawberries. CONCLUSION: These findings suggest that POS treatment could potentially be applied to maintain quality attributes, reduce decay, and further enrich the anthocyanin content and antioxidant capacity of strawberries during postharvest storage. The results also suggest that the positive effects of POS on strawberries could be associated with the rapid accumulation of chitinase and ß-1,3-glucanase activities, and the increase of PAL enzyme activity leading to the synthesis and accumulation of anthocyanins. © 2019 Society of Chemical Industry.

Asunto(s)

Conservación de Alimentos/métodos , Conservantes de Alimentos/farmacología , Fragaria/efectos de los fármacos , Frutas/química , Oligosacáridos/farmacología , Pectinas/farmacología , Antocianinas/análisis , Antioxidantes/análisis , Almacenamiento de Alimentos , Fragaria/química , Frutas/efectos de los fármacos , Valor Nutritivo , Fenoles/análisis , Fenilanina Amoníaco-Liasa/análisis

RESUMEN

The thioredoxin (TRX) system in crustaceans has demonstrated to act as a cell antioxidant being part of the immune response by dealing with the increased production of reactive oxygen species during bacterial or viral infection. Since the number of marine viruses has increased in the last years significantly affecting aquaculture practices of penaeids, and due to the adverse impact on wild and cultured shrimp populations, it is important to elucidate the dynamics of the shrimp response to viral infections. The role of Litopenaeus vannamei thioredoxin (LvTRX) was compared at both, mRNA and protein levels, in response to two viruses, the white spot syndrome virus (WSSV) and the infectious hypodermal and hematopoietic necrosis virus (IHHNV). The results confirmed changes in the TRX gene expression levels of WSSV-infected shrimp, but also demonstrated a more conspicuous response of TRX to WSSV than to IHHNV. While both the dimeric and monomeric forms of LvTRX were detected by Western blot analysis during the WSSV infection, the dimer on its reduced form was only detected through the IHHNV infectious process. These findings indicate that WSSV or IHHNV infected shrimp may induce a differential response of the LvTRX protein.

Asunto(s)

Densovirinae/fisiología , Regulación de la Expresión Génica , Penaeidae , Tiorredoxinas/genética , Tiorredoxinas/inmunología , Virus del Síndrome de la Mancha Blanca 1/fisiología , Animales , Perfilación de la Expresión Génica , Branquias/inmunología , Branquias/virología , Penaeidae/inmunología , Penaeidae/virología , Factores de Tiempo

RESUMEN

Thymidylate synthase (TS) catalyzes the synthesis of deoxythymidine monophosphate (dTMP), which is an essential precursor for DNA synthesis. The rationale underlying drug design is to identify compounds that differentially inhibit a viral or parasite enzyme vs. the host homologue. We studied the TS of the white spot syndrome virus (WSSV TS) and the corresponding TS from the host, the marine invertebrate shrimp Litopenaeus vannamei. TS is the only de novo source of dTMP and is essential for host and viral DNA replication. To establish proof of principle, we cloned a full-length TS cDNA from the white shrimp L. vannamei (shrimp TS) that corresponds to a deduced sequence of 289 amino acids and over-expressed it to study inhibition of both shrimp and viral TSs. Steady-state kinetic parameters for both TSs are similar, and dissociation (K(d)) or half maximal inhibitory concentration constants (IC(50)) did not show differential inhibition between the folate analogues. Differences in their amino acid sequence are not reflected in theoretical molecular models of both TSs, since both appear to have identical active sites. These results suggest that the eukaryotic TS active site is very constrained into the functional residues involved in reductive methylation of 2'-deoxyuridine-5'-monophosphate (dUMP).

Asunto(s)

Penaeidae/enzimología , Timidilato Sintasa/metabolismo , Virus del Síndrome de la Mancha Blanca 1/enzimología , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Dominio Catalítico/genética , Clonación Molecular , Nucleótidos de Desoxiuracil/metabolismo , Ácido Fólico/análogos & derivados , Ácido Fólico/farmacología , Antagonistas del Ácido Fólico/farmacología , Isoindoles/farmacología , Cinética , Modelos Moleculares , Datos de Secuencia Molecular , Filogenia , Quinazolinas/farmacología , Alineación de Secuencia , Timidilato Sintasa/antagonistas & inhibidores , Timidilato Sintasa/genética

RESUMEN

Thioredoxin (TRX) is a main component of the redox homeostasis machinery in the cell and it is required for ribonucleotide reductase function among others. In invertebrates, the redox balance is compromised during disease and changes in the physiological state and it is one of the components of the innate immune response. In this work, the shrimp (Litopenaeus vannamei) LvTRX cDNA was sequenced, cloned and over-expressed in bacteria to further characterize the function of the recombinant protein. LvTRX was able to reduce insulin disulfides and it was a better antioxidant compared to reduced glutathione and ascorbic acid, by means of the Trolox Equivalent Antioxidant Capacity (TEAC) assay. Interestingly, LvTRX contains aside of the canonical active site CXXC disulfide motif, one Cys (C73) residue in the interface of a putative dimer previously reported for human TRX. Using qRT-PCR, we found that shrimp LvTRX is mainly expressed in gills and pleopods; the variation of LvTRX mRNA upon hypoxia and re-oxygenation is not statistically significant. LvTRX stands as an important antioxidant that must be considered in future physiological and immune challenges studies.

Asunto(s)

Antioxidantes/metabolismo , Penaeidae/metabolismo , Tiorredoxinas/metabolismo , Secuencia de Aminoácidos , Animales , Ácido Ascórbico/metabolismo , Secuencia de Bases , Hipoxia de la Célula , Clonación Molecular , Disulfuros/metabolismo , Branquias/metabolismo , Glutatión/metabolismo , Hepatopáncreas/metabolismo , Insulina/metabolismo , Modelos Moleculares , Datos de Secuencia Molecular , Músculos/metabolismo , Oxidación-Reducción , Conformación Proteica , ARN Mensajero/metabolismo , Proteínas Recombinantes/metabolismo , Análisis de Secuencia de ADN , Análisis de Secuencia de Proteína , Tiorredoxinas/química , Tiorredoxinas/genética