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Key message: The miR822 together with of AGO9 protein, modulates monosporic development in Arabidopsis thaliana through the regulation of target genes encoding Cysteine/Histidine-Rich C1 domain proteins, revealing a new role of miRNAs in the control of megaspore formation in flowering plants. In the ovule of flowering plants, the establishment of the haploid generation occurs when a somatic cell differentiates into a megaspore mother cell (MMC) and initiates meiosis. As most flowering plants, Arabidopsis thaliana (Arabidopsis) undergoes a monosporic type of gametogenesis as three meiotically derived cells degenerate, and a single one—the functional megaspore (FM), divides mitotically to form the female gametophyte. The genetic basis and molecular mechanisms that control monosporic gametophyte development remain largely unknown. Here, we show that Arabidopsis plants carrying loss-of-function mutations in the miR822, give rise to extranumerary surviving megaspores that acquire a FM identity and divides without giving rise to differentiated female gametophytes. The overexpression of three miR822 putative target genes encoding cysteine/histidine-rich C1 (DC1) domain proteins, At5g02350, At5g02330 and At2g13900 results in defects equivalent to those found in mutant mir822 plants. The three miR822 targets genes are overexpressed in ago9 mutant ovules, suggesting that miR822 acts through an AGO9-dependent pathway to negatively regulate DC1 domain proteins and restricts the survival of meiotically derived cells to a single megaspore. Our results identify a mechanism mediated by the AGO9-miR822 complex that modulates monosporic female gametogenesis in Arabidopsis thaliana. [ABSTRACT FROM AUTHOR]

We evaluated the cytotoxic and genotoxic effects of protein isolates of ayocote beans on adult male CD1+ mice and the anticancer activity of their protein fractions using SiHa Cells. The mice that received protein isolate showed a Polychromatic Erythrocytes (PCE) increase at 48 h; a significant PCE decrease was observed in mice administered the protein isolate-Daunorubicin (isolate-DAU) mix. A micronucleated erythrocytes (MNE) increase was observed in mice that received the mix in all times tested. All protein fractions of ayocote beans (black and purple) showed inhibition against SiHa cells proliferation at doses of 3000 or 5000 µg/mL. The maximal inhibitory concentration (IC50) of each protein fraction was reached at a concentration of 5000 µg/mL. A synergistic effect of isolate-DAU was observed in the in vivo test; the effect of the protein fractions on SiHa cells proliferation depended of the ayocote bean variety used. [ABSTRACT FROM AUTHOR]

Starches isolated from four ayocote bean varieties were modified by thermal treatment to determinate the effect of the treatment on the structural changes of ayocote bean starch. Scanning electron microscopy indicates that the starch granules have oval and round shapes, with heterogeneous sizes and fractures when the extraction method is used. The presence of new bands at 2850 and 1560 cm in the FT-IR spectra showed that the thermal treatment of ayocote beans induced an interaction between the protein or lipid and the amylose or amylopectin, while the sharpest band at 3400 cm indicated a dehydration process in the starch granule in addition to the presence of the band at 1260 cm, indicating the product of the retrogradation process. The thermal treatment reduced the crystallinity as well as short-range order. Raman spectroscopy revealed that acute changes occurred in the polysaccharide bonds after thermal treatment. This study showed that the thermal treatment affected the structural properties of ayocote bean starches, the interactions of the lipids and proteins with starch molecules and the retrogradation process of starch. [ABSTRACT FROM AUTHOR]