Defensin c-thionin from Capsicum chinense improves butyrate cytotoxicity on human colon adenocarcinoma cell line Caco-2

BACKGROUND: Butyrate is a histone deacetylase inhibitor that induces apoptosis and inhibits cell proliferation of colorectal cancer cells. To improve its anticancer activity, butyrate has been evaluated mixed with drugs and different molecules. Plant antimicrobial peptides are attractive anticancer alternative molecules because they show selective cytotoxic activity against different cancer cell lines. In this work, we explore if the plant defensin c-thionin (Capsicum chinense) can improve butyrate activity on Caco-2 cell line and we also determined the mechanism of death activated. RESULTS: The combined treatment of c-thionin (3.5 mM) and butyrate (50 mM) showed higher cytotoxicity on Caco-2 cells with respect to single treatments. Also, the combined treatment reduced cell proliferation and exhibited a higher rate of apoptosis than single treatments. Combined treatment induced caspases 8 and 9 activation to an extent comparable with that of butyrate while c-thionin did not activate caspases. Additionally, reactive oxygen species generation preceded the onset of apoptosis, and superoxide anion production was higher in cells treated with the combined treatment. CONCLUSIONS: The c-thionin from Habanero chili pepper improved the butyrate cytotoxicity on Caco-2 cells. This effect occurred through apoptosis induction associated with reactive oxygen species production. Therefore, the combination of butyrate with cytotoxic antimicrobial peptides could be an attractive strategy for cancer therapy.

Production of biquinho pepper in different growing seasons characterized by the logistic model and its critical points / Produção de pimenta biquinho em diferentes épocas de cultivo caracterizadas pelo modelo logístico e seus pontos críticos

ABSTRACT: The objective of this study was to characterize the production of biquinho pepper through the interpretation of parameter estimates from the logistic model and its critical points obtained by the partial derivatives of the function, and to indicate the best cultivar and growing season for subtropical climate sites. For this, a 2x3 factorial experiment was conducted with two cultivars of biquinho pepper (BRS Moema and Airetama biquinho) in three growing seasons (E1: October 2015, E2: November 2015, E3: January 2016). The logistic non-linear model for fruit mass was specified as a function of the accumulated thermal sum, and the critical points were calculated through the partial derivatives of the model, in order to characterize the productive performance of the crop by the biological interpretation of the estimates of the three set parameters. In E3, temperatures close to 0 ºC during the experiment were lethal to the plants, and a linear regression model was used in this case. The production of the cultivars in E1 and E2 were well characterized by the estimated logistic models, and the most productive cultivar was Airetama biquinho in all evaluated seasons. This cultivar also presented higher concentration of production. The two cultivars did not differ significantly with regards to productive precocity. For E3, it was not possible to interpret the parameters in the same way as for E1 and E2, since the use of the linear model did not allow the same interpretations performed for the nonlinear model, reaffirming its applicability horticultural crops of multiple harvests.

RESUMO: O objetivo deste estudo foi caracterizar a produção de pimenta biquinho através da interpretação dos parâmetros do modelo Logístico e seus pontos críticos obtidos pelas derivadas parciais da função, bem como indicar qual a melhor cultivar e a melhor época de cultivo para locais de clima subtropical. Conduziu-se um experimento em esquema fatorial 2x3 sendo duas cultivares de pimenta biquinho (BRS Moema e Airetama biquinho), em três épocas de cultivo (E1: outubro de 2015, E2: 01 de novembro 2015 e E3: janeiro de 2016). Ajustou-se o modelo logístico para massa de frutos em função da soma térmica acumulada, e calculou-se os pontos críticos através das derivadas parciais do modelo com a finalidade de caracterizar o desempenho produtivo da cultura através da interpretação biológica destes parâmetros. Temperaturas próximas a 0 ºC durante o experimento foram letais às plantas, e por isso, para a época 3, ajustou-se um modelo de regressão linear. A interpretação dos parâmetros do modelo Logístico e seus pontos críticos permitiram que a produção das cultivares nas épocas 1 e 2 fossem caracterizadas, sendo que a cultivar mais produtiva é Airetama biquinho em todas as épocas de transplante. Essa cultivar também apresenta maior concentração de produção no período. Quanto a precocidade produtiva as duas cultivares não diferiram significativamente. Sobre a época 3, não foi possível interpretar da mesma forma, pois o ajuste do modelo linear não permite as mesmas interpretações realizadas para o modelo não linear, reafirmando a sua aplicabilidade em cultura olerícolas de múltiplas colheitas.

Cloning and molecular characterization of a putative habanero pepper SERK1 cDNA expressed during somatic and zygotic embryogenesis

Background: Plant gene homologs that control cell differentiation can be used as biotechnological tools to study the in vitro cell proliferation competence of tissue culture-recalcitrant species such as peppers. It has been demonstrated that SERK1 homologs enhance embryogenic competence when overexpressed in transformed tissues; therefore, cloning of a pepper SERK1 homolog was performed to further evaluate its biotechnological potential. Results: A Capsicum chinense SERK full-length cDNA (CchSERK1) was cloned and characterized at the molecular level. Its deduced amino acid sequence exhibits high identity with sequences annotated as SERK1 and predicted-SERK2 homologs in the genomes of the Capsicum annuum CM-334 and Zunla-1 varieties, respectively, and with SERK1 homologs from members of the Solanaceae family. Transcription of CchSERK1 in plant tissues, measured by quantitative RT-PCR, was higher in stems, flowers, and roots but lower in leaves and floral primordia. During seed development, CchSERK1 was transcribed in all zygotic stages, with higher expression at 14 days post anthesis. During somatic embryogenesis, CchSERK1 was transcribed at all differentiation stages, with a high increment in the heart stage and lower levels at the torpedo/cotyledonal stages. Conclusion: DNA sequence alignments and gene expression patterns suggest that CchSERK1 is the C. chinense SERK1 homolog. Significant levels of CchSERK1 transcripts were found in tissues with cell differentiation activities such as vascular axes and during the development of zygotic and somatic embryos. These results suggest that CchSERK1 might have regulatory functions in cell differentiation and could be used as a biotechnological tool to study the recalcitrance of peppers to proliferate in vitro.

Efecto bacteriostático y bactericida de extractos de ají panca (Capsicum chinense) y pimiento (Capsicum annuum var. annuum) sobre cultivos de Escherichia coli ATCC 25922 y Staphylococcus aureus ATCC 25923 / Bacteriostatic and bactericidal effect of extracts of red pepper (Capsicum chinense) and pepper (Capsicum annuum var. Annuum) on cultures of Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923

En la actualidad, es creciente el interés por nuevas alternativas para reemplazar los antimicrobianos químicos debido a los efectos adversos para el consumidor. Existen especies botánicas con efecto antimicrobiano como los frutos de Capsicum que son de uso común en nuestro país. Los extractos obtenidos de los ajíes y pimientos poseen compuestos activos con efecto antimicrobiano sobre bacterias, hongos y virus; además, su uso es seguro debido a su naturaleza orgánica. Por ello, el objetivo del presente estudio fue evaluar la actividad bacteriostática y bactericida de extractos de Ají Panca (Capsicum chinense) y Pimiento (Capsicum annuum var. annuum) sobre Escherichia coli ATCC 25922 y Staphylococcus aureus ATCC 25923. Se elaboró extracto de ambos frutos con rendimientos de 12.53 ± 0.30% y 12.17 ± 0.23% para Ají Panca y Pimiento, respectivamente. Asimismo, el extracto de ají panca contuvo 1.39 mg de capsaicina y 0.54 mg de dihidrocapsaicina, determinadas por HPLC. Estos compuestos no se analizaron para el pimiento ya que los niveles son no detectables en variedades dulces. Se evaluó el efecto de ambos extractos a concentraciones de 25, 12.5, 6.25, 3.13, 1.56, 0.78, 0.39, 0.20, 0.10 y 0.04% usando el método de microdilución en caldo y posterior crecimiento en agares selectivos. Los resultados muestran que no existe efecto bacteriostático para ambas cepas. Asimismo, la viabilidad de E. coli ATCC 25922 no fue afectada por los dos extractos mientras que para S. aureus ATCC 25923 solo el ají panca no afecto su viabilidad. Finalmente, el efecto bactericida para S. aureus ATCC 25923, fue observado con el extracto de pimiento a concentraciones de 25, 12.5 y 6.25%.

Influence of osmotic dehydration on ascorbic acid loss in pickled dry peppers (Capsicum chinense)

The objective of this work was (1) to develop a dehydrated pepper with 45% humidity, determining the drying curves for pepper, with and without osmotic pre-treatment and (2) to evaluate the influence of both drying and osmotic treatment on the content ascorbic acid (vitamin C) in fresh pepper and pepper with 45% humidity. The experiments were carried out using the peppers cut in half, with and without osmotic pre-treatment, followed by drying in an oven at 70 ºC. The results showed that the osmotic pretreatment did not influence the retention of ascorbic acid during the drying of pepper. The sensory analysis regarding the color, flavor, and texture attributes revealed that there was no difference in the acceptability.

Antimicrobial effects of plant defence peptides expressed by bovine endothelial cells on intracellular pathogens

Background: The actions of plant antimicrobial peptides (PAP) against intracellular pathogens are poorly known. It has been reported that wheat puroindolines show antibacterial activity against Staphylococcus epidermidis endocyted by macrophages. In this work, we evaluated the intracellular antimicrobial activity of PAP gamma-thionin and thionin Thi2.1 produced by bovine endothelial cells against intracellular Staphylococcus aureus and Candida albicans. We used three host-pathogen models: 1) bovine mammary epithelial cells (BMEC)-S. aureus, 2) bovine endothelial cells (BEC)-S. aureus and 3) BEC-C. albicans, and evaluated the effect of conditioned media from BEC producers of PAP (gamma-thionin and thionin Thi2.1). Results: In the first model, conditioned medium (CM) containing Thi2.1 completely inhibited S. aureus intracellular after 24 hrs treatment. In the second model, CM from BEC containing gamma-thionin has a better effect killing intracellular S. aureus for 12-24 hrs incubations than CM from endothelial cells producers of Thi2.1; this was related with an increase of nitric oxide production (~2 times) in BEC infected and treated for 12 hrs with CM containing gamma-thionin, which negatively correlates with bacterial viability. In the third model, CM containing Thi2.1 showed a more potent intracellular fungicidal activity (~85 percent of inhibition) at 24 hrs treatment than CM containing gamma-thionin (~35 percent of inhibition). Conclusions: This work shows new effects of PAP to control intracellular bacterial or fungal infections.