DNA methylation profile of a rural cohort exposed to early-adversity and malnutrition: An exploratory analysis.

Barker's hypothesis affirms that undernourishment in early-life induces metabolic reprogramming that compromises organism functions later in life, leading to age-related diseases. We are exposed to environmental and social conditions that impact our life trajectories, leading to ageing phenotypes as we grow. Epigenetic mechanisms constitute the link between both external stimuli and genetic programming. Studies have focused on describing the effect of early adverse events such as trauma, famines, or childhood labor on epigenetic markers in adulthood and the elderly. However, we lack information on epigenetic programming in individuals born in rural communities from underdeveloped countries, exposed to negative influences during fetal and postnatal development, particularly chronic malnutrition. Hence, in this exploratory analysis, we characterize the epigenome of individuals and some parents from Tlaltizapan (a rural community in Mexico originally studied almost 50 years ago) and collect anthropometric data on growth and development, as well on the living conditions of the families. Our results help build a biological hypothesis indicating that most of the epigenetic age measures of the subjects are significantly different among them. Interestingly, the most affected methylated regions correspond to pathways involved in neuronal system development, reproductive behaviour, learning and memory regulation.

First insight into plastics ingestion by fish in the Gulf of California, Mexico.

Plastic particle occurrence in the digestive tracts of fishes from a tropical estuarine system in the Gulf of California was investigated. A total of 1095 fish were analysed, representing 15 species. In total 1384 particles of plastic debris were recovered from the gastrointestinal tracts of 552 specimens belonging to 13 species, and all consisted of threads, the majority of which were small microplastics (0.23 to 1.89), followed by large microplastics (2.07 to 4.49), and few mesoplastics (5.4 to 19.86). Plastic particles were identified using ATR-FTIR spectroscopy. The mean frequency of occurrence of plastics in the gastrointestinal tracts of fishes from this system was 50.5%, which is higher than frequencies reported in similar systems in other areas. The polymers identified by ATR-FTIR were polyamide (51.2%), polyethylene (36.6%), polypropylene (7.3%), and polyacrylic (4.9%). These results show the first evidence of plastic contamination for estuarine biota in the Gulf of California.