Metabolic Responses of the Microalga Neochloris oleoabundans to Extracellular Self- and Nonself-DNA.

Stressed organisms identify intracellular molecules released from damaged cells due to trauma or pathogen infection as components of the innate immune response. These molecules called DAMPs (Damage-Associated Molecular Patterns) are extracellular ATP, sugars, and extracellular DNA, among others. Animals and plants can recognize their own DNA applied externally (self-exDNA) as a DAMP with a high degree of specificity. However, little is known about the microalgae responses to damage when exposed to DAMPs and specifically to self-exDNAs. Here we compared the response of the oilseed microalgae Neochloris oleoabundans to self-exDNA, with the stress responses elicited by nonself-exDNA, methyl jasmonate (MeJA) and sodium bicarbonate (NaHCO3). We analyzed the peroxidase enzyme activity related to the production of reactive oxygen species (ROS), as well as the production of polyphenols, lipids, triacylglycerols, and phytohormones. After 5 min of addition, self-exDNA induced peroxidase enzyme activity higher than the other elicitors. Polyphenols and lipids were increased by self-exDNA at 48 and 24 h, respectively. Triacylglycerols were increased with all elicitors from addition and up to 48 h, except with nonself-exDNA. Regarding phytohormones, self-exDNA and MeJA increased gibberellic acid, isopentenyladenine, and benzylaminopurine at 24 h. Results show that Neochloris oleoabundans have self-exDNA specific responses.

Vasorelaxant activity of Euphorbia furcillata Kunth mainly by activation of NO/cGMP pathway and calcium channel blockade / Actividad vasorrelajante de Euphorbia furcillata Kunth principalmente por activación de la vía NO/GMPc y bloqueo de canales de calcio]

The aim of current study was to determinate ex vivo and chromatographic fingerprint by HPLC of four extracts of Euphorbia furcillata K. Ethyl acetate extract of Euphorbia furcillata (EaEEf) was the most effective and potent extract (Emax=98.69±1.24%) and its effect was partially endothelium-dependent. Functional vasorelaxant mechanism of action of EaEEf was determinate, EaEEf showed efficient relaxation of KCl [80 mM]-induced contraction and norepinephrine and CaCl2 contraction curves showed diminution of maximal contraction in the presence of EAEEf and EaEEf-relaxation curve was shifted to the right in the presence of L-NAME (nitric oxide synthase inhibitor) and ODQ (guanylate cyclase inhibitor). Chromatographic fingerprints analysis suggests presence of diterpenoid such as abietane, tigliane, and ingenane skeletons. Our experiments suggest the EaEEf vasorelaxant activity could be attributed to diterpenoid molecules whose mechanism involves nitric oxide production and calcium channel blockade.

Se determinó el efecto vasorrelajante ex vivo y los perfiles cromatográficos mediante HPLC de cuatro extractos de Euphorbia furcillata K.. El extracto de acetato de etilo de E. furcillata (EaEEf) fue el más eficaz y potente en la contracción inducida por norepinefrina (Emax=98.69±1.24%) y el efecto fue parcialmente dependiente del endotelio vascular. Se determinó el mecanismo de acción vasorrelajante para EaEEf, este mostró ser eficaz sobre la contracción inducida por KCl [80 mM] y la curva de contracción en respuesta a norepinefrina y CaCl2 en presencia de EaEEf mostró disminución en la contracción máxima, mientras que la curva de relajación de EaEEf en presencia de L-NAME (inhibidor de óxido nítrico sintasa) y ODQ (inhibidor de guanilato ciclasa) se desplazó hacia la derecha. El análisis cromatográfico de EaEEf sugiere la presencia de moléculas diterpenoides como abietano, tigliano y esqueletos de ingenano. Nuestros resultados sugieren que el efecto vasorrelajante de EaEEf podría atribuirse a moléculas diterpenoides, cuyo mecanismo de acción involucra la producción de óxido nítrico y bloqueo de canales de calcio.