Water behavior on liposomes with Pro and Gb in hydric stress conditions by FTIR-ATR

ROSA, A. SEBASTIAN; ANIBAL EDGARDO DISALVO; FRIAS, M DE LOS ANGELES

Buenos Aires

Congreso; Reunión Conjunta De Sociedades De Biociencias; 2017

Sociedad Argentina de Biofísica

Glycine Betaine (GB) and Proline (Pro) are two major organic osmolytes that accumulate in a variety of plant species in response to environmental stresses such as drought, salinity and extreme temperatures. Although their actual roles in plant osmotolerance are thought to be as osmolytes their effects on membrane integrity along with adaptive roles in mediating osmotic adjustment in plants grown under stress conditions remain controversial. In particular, it is of interest to analyze the effects of these aminoacids on membrane structure and hydration. In this context, the interaction of GB and Pro with the hydration centers of DPPC membrane phosphates, carbonyls and acyl chains was evaluated at controlled hydration and temperature by FTIR-ATR was analyzed. In the same direction, in order to evaluate the water behavior different populations of water bands were also studied. No significant changes are observed in the frequency of phosphate groups in the presence of GB and Pro at different RH. In contrast, at low hydration degrees (11% RH), DPPC carbonyl groups in the presence of Pro show an increase in the bounded population compared to pure DPPC. In the presence of Gb no significant differences are observed between both populations and pure DPPC. The most noticeable changes were observed at the methylenes groups at different RH indicating that water between aliphatic chains (confined water) remain at low hydration degrees in the presence of high concentrations of both aminoacids. A similar behavior in the water content and confined water was observed in ETERPC MLV´s. These results suggest that these aminoacids enhance the water entrapment in the membrane, a response that may be helpful to interpret their preservative properties in hydric stress process.