Morphological, anatomical and physiological frond traits of Cheilanthes persica (Bory) Mett. ex Kuhn were studied to analyze its adaptive strategy. Mean frond life span is about 340 d. Mature fronds are characterized by 91 g m-2 areal dry mass (ADM) and 217 g m-2 succulence. The reduction of frond water content in July (dehydration phase) caused a 51 % decrease in frond surface area (SA). Fronds were dry in August (desiccation phase); nevertheless, in September they showed an increased SA (rehydration phase). Chlorophyll (Chl) a/b ratio, above 3, and the well developed palisade parenchyma (two layers, total thickness of 103.9 µm) are typical for sun leaves. Chl and carotenoid contents and net photosynthetic rate (PN) increased during frond development until the highest values in April-May (maturity phase). When mean air temperature reached 31.3 °C, stomatal conductance (gs) decreased by 34 % and PN by 33 %. The high pigment contents can dissipate the excess of radiant energy, particularly under unfavourable conditions, when PN is low. Rather high PN was found during the rehydration stage. The pronounced decline of mesophyll activity during the declining phase was confirmed by the lowest PN. and L. Gratani, M. F. Crescente, G. Rossi.
A side effect of diabetes is formation of glycated proteins and, from them, production of advanced early glycation end products that could determine aberrant immune responses at the systemic level. We investigated a relevant aberrant post-translational modification (PTM) in diabetes based on synthetic peptides modified on the lysine side chain residues with 1-deoxyfructopyranosyl moiety as a possible modification related to glycation. The PTM peptides were used as molecular probes for detection of possible specific autoantibodies developed by diabetic patients.
The PDC-E2(167-186) sequence from the pyruvate dehydrogenase complex was selected and tested as a candidate peptide for antibody detection. The structure-based designed type I’ β-turn CSF114 peptide was also used as a synthetic scaffold. Twenty-seven consecutive type 1 diabetic patients and 29 healthy controls were recruited for the study. In principle, the ‘chemical reverse approach’, based on the use of patient sera to screen the synthetic modified peptides, leads to the identification of specific probes able to characterize highly specific autoantibodies as disease biomarkers of autoimmune disorders. Quite surprisingly, both peptides modified with the (1-deoxyfructosyl)-lysine did not lead to
significant results. Both IgG and IgM differences between the two populations were not significant. These data can be rationalized considering that i) IgGs in diabetic subjects exhibit a high degree of glycation, leading to decreased functionality; ii) IgGs in diabetic subjects exhibit a privileged response vs proteins containing advanced glycation products (e.g., methylglyoxal, glyoxal, glucosone, hydroimidazolone, dihydroxyimidazolidine) and only a minor one with respect to (1-deoxyfructosyl)-lysine. and Corresponding authors: Anna Maria Papini; Annunziata Lapolla