Is Aging a Disease? A Critical Review Within the Framework of Ageism.

Ageism is a type of discrimination characterized by negative social representations of old age and aging, with prejudices and stereotypes that cause rejection and marginalization of older adults, generally considering them as fragile and unproductive. For this reason, it is recognized as one of the main enemies of healthy aging, especially when it arises from the scientific and professional fields. In this sense, the proposals promoted by some researchers regarding the World Health Organization (WHO) classifying aging as a disease goes against the healthy aging approach. In this sense, we consider that there is no theoretical or scientific support to classify aging as a disease, so we must advocate before the WHO so that aging is eliminated within its disease classification codes. In this framework, this review proposes the concept of "hallmarks of ageism" defined as the characteristics, representations and attitudes of rejection and discrimination towards aging, old age and older people, at the political and institutional, scientific or professional, technological and digital, social, family and personal levels, which are presented in an articulated and structured manner. For this reason, it is essential to comprehensively identify and analyze the "hallmarks of ageism", in order to propose programs that include strategies and public policies that promote "anti-ageism" as a counterproposal to the "hallmarks of aging", whose biological changes related to aging are intended to be comparable to chronic non-communicable diseases.

Arbuscular Mycorrhizal Symbiosis Leads to Differential Regulation of Genes and miRNAs Associated with the Cell Wall in Tomato Leaves.

Arbuscular mycorrhizal symbiosis is an association that provides nutritional benefits to plants. Importantly, it induces a physiological state allowing plants to respond to a subsequent pathogen attack in a more rapid and intense manner. Consequently, mycorrhiza-colonized plants become less susceptible to root and shoot pathogens. This study aimed to identify some of the molecular players and potential mechanisms related to the onset of defense priming by mycorrhiza colonization, as well as miRNAs that may act as regulators of priming genes. The upregulation of cellulose synthases, pectinesterase inhibitors, and xyloglucan endotransglucosylase/hydrolase, as well as the downregulation of a pectinesterase, suggest that the modification and reinforcement of the cell wall may prime the leaves of mycorrhizal plants to react faster and stronger to subsequent pathogen attack. This was confirmed by the findings of miR164a-3p, miR164a-5p, miR171e-5p, and miR397, which target genes and are also related to the biosynthesis or modification of cell wall components. Our findings support the hypothesis that the reinforcement or remodeling of the cell wall and cuticle could participate in the priming mechanism triggered by mycorrhiza colonization, by strengthening the first physical barriers upstream of the pathogen encounter.