Use of molecular dynamics simulations to study the interactions between barley allelochemicals and plant plasma membrane

Gramine and hordenine, two alkaloids produced by barley, were shown to inhibit the growth of a common weed (Matricaria recutita L.). This feature could be useful in order to reach a more sustainable weeds management. In vitro experiments have proven that both molecules do interact with lipid bilayers (made of a phosphatidylglycerol (PG) lipid) mimicking plant plasma membranes and are able to modify some of their properties. Moreover, gramine was shown to be more effective than hordenine in both inhibiting weeds growth and altering lipid bilayers properties, suggesting that interactions with membranes could be linked to their mode of action. Molecular dynamics (MD) simulations are carried out in order to get an insight into the molecular mechanisms that underlie these interactions with model membranes and to discriminate between gramine behavior and hordenine behavior

Linoleic and linolenic acid hydroperoxides interact differentially with biomimetic plant membranes in a lipid specific manner

Linoleic and linolenic acid hydroperoxides (HPOs) constitute key intermediate oxylipins playing an important role as signaling molecules during plant defense processes in response to biotic or abiotic stress. They have also been demonstrated in vitro as antimicrobial agents against plant fungi and bacteria. To reach the phytopathogens in vivo, the HPOs biosynthesized in the plant cells must cross the plant plasma membrane (PPM) where they can also interact with plasma membrane lipids and have an effect on their organization.In the present study, we have investigated the interaction properties of HPOs with PPM at a molecular level using biophysical tools combining in vitro and in silico approaches and using plant biomimetic lipid systems. Our results have shown that HPOs are able to interact with PPM lipids and perturb their lateral organization. Glucosylceramide (GluCer) is a privileged partner, sitosterol lessens their binding and the presence of both GluCer and sitosterol further reduces their interaction. Hydrophobic effect and polar interactions are involved in the binding. The chemical structure of HPOs influences their affinity for PPM lipids. The presence of three double bonds in the HPO molecule gives rise to a higher affinity comparatively to two double bonds, which can be explained by their differential interaction with the lipid polar headgroups.ARC-FIELD project 13/17-1

Interleukin-7 Regulates Adipose Tissue Mass and Insulin Sensitivity in High-Fat Diet-Fed Mice through Lymphocyte-Dependent and Independent Mechanisms

Although interleukin (IL)-7 is mostly known as a key regulator of lymphocyte homeostasis, we recently demonstrated that it also contributes to body weight regulation through a hypothalamic control. Previous studies have shown that IL-7 is produced by the human obese white adipose tissue (WAT) yet its potential role on WAT development and function in obesity remains unknown. Here, we first show that transgenic mice overexpressing IL-7 have reduced adipose tissue mass associated with glucose and insulin resistance. Moreover, in the high-fat diet (HFD)-induced obesity model, a single administration of IL-7 to C57BL/6 mice is sufficient to prevent HFD-induced WAT mass increase and glucose intolerance. This metabolic protective effect is accompanied by a significant decreased inflammation in WAT. In lymphocyte-deficient HFD-fed SCID mice, IL-7 injection still protects from WAT mass gain. However, IL-7-triggered resistance against WAT inflammation and glucose intolerance is lost in SCID mice. These results suggest that IL-7 regulates adipose tissue mass through a lymphocyte-independent mechanism while its protective role on glucose homeostasis would be relayed by immune cells that participate to WAT inflammation. Our observations establish a key role for IL-7 in the complex mechanisms by which immune mediators modulate metabolic functions

Plant esterified oxylipins: structure – function relationship

In the present work, high quantities of arabidopsides were extracted and purified from Arabidopsis thaliana L

Development of a new method for arabidopsides extraction and purification

In the present work, a new method for arabidopsides extraction and purification was developed