23 research outputs found
Chemical composition and antibacterial activity of essential oils from the medicinal plant Mentha cervina L. grown in Portugal
Mentha cervina is a medicinal plant traditionally
used in Portugal in folk medicine, in different gastric
disorders and inflammations of the respiratory tract. In
order to validate those traditional uses, M. cervina essential
oils (EOs) were characterized by GC and GC–MS and their
antimicrobial activity was tested against 23 bacterial strains
(including multiresistant strains). The EOs were dominated
by the monoterpenes pulegone (52–75%), isomenthone
(8–24%), limonene (4–6%), and menthone (1–2%). The
antibacterial activity of these EOs was compared to that of
the main components standards. The most effective antibacterial
activity was expressed by the EOs against the
Gram-negative bacteria, Escherichia coli and Acinetobacter
baumanni, with MIC values of 1 mg/ml. The EOs complex mixtures were more active than the individual
aromatic components supporting the hypothesis that the
EOs antibacterial activity is a function of the synergistic
effect of their different aromatic components. These results
show the potential role of M. cervina EOs as antibacterial
agents and validate the traditional use of this plant
Sphingolipid-induced cell death in Arabidopsis is negatively regulated by the papain-like cysteine protease RD21
It is now well established that sphingoid Long Chain Bases (LCBs) are crucial mediators of programmed cell death. In plants, the mycotoxin fumonisin B1 (FB1) produced by the necrotrophic fungus Fusarium moniliforme disrupts the sphingolipid biosynthesis pathway by inhibiting the ceramide synthase leading to an increase in the amount of phytosphingosine (PHS) and dihydrosphingosine (DHS), the two major LCBs in Arabidopsis thaliana. To date, the signaling pathway involved in FB1-induced cell death remains largely uncharacterized. It is also well acknowledged that plant proteases such as papain-like cysteine protease are largely involved in plant immunity. Here, we show that the papain-like cysteine protease RD21 (responsive-to-desiccation-21) is activated in response to PHS and FB1 in Arabidopsis cultured cells and leaves, respectively. Using two allelic null mutants of RD21, and two different PCD bioassays, we demonstrate that the protein acts as a negative regulator of FB1-induced cell death in Arabidopsis