Maria Giuseppina Campanile

Expansin-like A (EXLA) proteins belong to one of the four main families within the expansin superfamily, a group of plant proteins essential for cell wall loosening. Here, we report, for the first time, the purification of a novel EXLA, named cpEXLA, from canihua seeds. cpEXLA (yield ~0.16 mg per 100 g of seeds) is a 29 kDa glycoprotein with a high melting temperature (Tm of 86.75 ± 1.06 °C). Elucidation of its primary structure reveals that the mature protein consists of 246 amino acids, ten of which are cysteine residues forming five disulphide bridges. Structural studies based on 3D model prediction reveal the presence of N- and C-terminal domains, which are typical of EXLAs and rich in β-sheets, as confirmed by circular dichroism (CD) spectroscopy. Furthermore, comparative analysis of amino acid sequences between cpEXLA and 219 similar EXLAs, retrieved from dicotyledonous genomes and transcriptomes, identified eighteen invariant amino acid residues: eleven in the N-terminal domain and seven in the C-terminal domain. Finally, phylogenetic analysis of EXLAs in dicotyledonous species shows a close relationship with other EXLAs from the Amaranthaceae family, confirming that EXLA proteins are highly conserved among dicotyledonous plants. Overall, cpEXLA represents an intriguing native tool for studying cell wall evolution and the functional role of EXLAs.

Here, the proximate composition, total amino acid content and antioxidant activity of Agria, Désirée and Kennebec potato varieties cultivated on the Matese plateau (Campania region, Southern Italy) were evaluated. Significant differences were observed among varieties in terms of proteins (1.98–3.07 g/100 g FW), carbohydrates (12.05–15.78 g/100 g FW) and moisture (78.42–84.68 g/100 g FW), while lipids were consistently low (~0.1 g/100 g FW), ~2.6-fold lower than ‘gold’ potatoes, used as a reference. Ashes were relatively high (1.10–1.39 g/100 g FW), ~1.4-fold higher than ‘gold’ potatoes. Total amino acid profiles were similar, although statistically significant differences were observed for Glx (glutamic acid + glutamine) and Asx (aspartic acid + asparagine), which are the most abundant amino acids, followed by valine, arginine and lysine. The chemical score of essential amino acids highlights that Matese potato varieties have a high nutritional content of phenylalanine + tyrosine and threonine, with average chemical scores of ~99.8% and 91.6%, respectively, while leucine is the limiting amino acid. The free amino acid profile does not show statistically significant differences. The total phenolic content (TPC) of analysed varieties (57.85–123.27 mg GAE/100 g of FW) was higher than those reported in the literature and directly correlated with the evaluated antioxidant activity (ABTS and DPPH). Finally, Matese potatoes are rich in potassium, phosphorus, calcium and magnesium, with minor minerals (~1.6%) and selenium traces (~0.53 µg/100 g FW). Overall, these findings highlight the potential of Matese potatoes to enhance local consumption, preserve culinary heritage and support gastronomic tourism growth.

Rye (Secale cereale L.) from Matese mountains is a local landrace cultivated in Southern Italy. To promote the benefits for the mountain economy, we report on the nutritional values (crude proteins, lipids, moisture, ash and total amino acids), metabolic traits (free amino acids, fatty acids and bioactive organic compounds) and mineral content of ‘segale del Matese’ seeds. Seeds were collected in 2023 and 2024 at two altitudes (~1000 and 150 m a.s.l.); these were analyzed, and the results were compared. Average data from two sites (crude proteins (9.6 g/100 g), lipids (1.3 g/100 g), ash (1.8 g/100 g), moisture (9.3 g/100 g) and carbohydrates (78.3 g/100 g)) show few significant statistical differences. The same trend was observed for total amino acid content, except for Glx (glutamic and glutamine), while statistical differences between the two sites were found among proteinogenic free amino acids. Moreover, segale del Matese’ is rich in polyunsaturated (linoleic and linoleic) and monounsaturated (oleic) fatty acids. Furthermore, total phenolic content, some bioactive compounds (i.e., gallic acid, vanillic acid, p-coumaric acid and ferulic acid) and radical scavenging activity were estimated. Finally, the seeds subjected to thermal treatment showed a decrease in anti-trypsin and anti-chymotrypsin activities, resulting in a favorable depletion of antinutritional factors.

Ribosome inactivating proteins (RIPs) are specific N-β-glycosylases that are well-characterized in plants. Their enzymatic action is to damage ribosomes, thereby blocking protein translation. Recently, several research groups have been working on the screening for these toxins in edible plants to facilitate the use of RIPs as biotechnological tools and biopesticides and to overcome public prejudice. Here, four novel monomeric (type 1) RIPs have been isolated from the seeds of Atriplex hortensis L. var. rubra, which is commonly known as edible red mountain spinach. These enzymes, named hortensins 1, 2, 4, and 5, are able to release the β-fragment and, like many other RIPs, adenines from salmon sperm DNA, thus, acting as polynucleotide:adenosine glycosidases. Structurally, hortensins have a different molecular weight and are purified with different yields (hortensin 1, ~29.5 kDa, 0.28 mg per 100 g; hortensin 2, ~29 kDa, 0.29 mg per 100 g; hortensin 4, ~28.5 kDa, 0.71 mg per 100 g; and hortensin 5, ~30 kDa, 0.65 mg per 100 g); only hortensins 2 and 4 are glycosylated. Furthermore, the major isoforms (hortensins 4 and 5) are cytotoxic toward human continuous glioblastoma U87MG cell line. In addition, the morphological change in U87MG cells in the presence of these toxins is indicative of cell death triggered by the apoptotic pathway, as revealed by nuclear DNA fragmentation (TUNEL assay).