Decrease In Micronutrients Research Articles

Spatio-Temporal Disposition of Micronutrients in Green Bean Grown in Sandy Mulching Soils

Currently, there is no information available about the spatio-temporal distribution of micronutrients in sandy mulching soils widely used in the southeast of Spain; therefore, in this experiment, we aimed to characterize the spatio-temporal distribution of micronutrients in the wet bulb zone in two sand-mulched soils. Four different factors were considered over the experiment: (a) soil model, (b) time sampling, (c) distance from the emitter, and (d) depth. Each soil was divided into four blocks and the soil sample per block was composed of 20 subsamples. The micronutrient concentration was determined in each soil sample through atomic absorption spectrometry determinations. To establish the relationship between factors, a multifactor ANOVA test analysis was conducted. The results obtained reported a higher micronutrient concentration in the soil profile than in the sand layer. Moreover, in the soil profile, there was a decrease in micronutrient concentration in distance for Fe (from 10.4 to 7.9 mg kg−1), Zn (from 4.0 to 3.5 mg kg−1), Mn (from 23.9 to 16.2 mg kg−1), and Cu forms (from 2.5 to 1.5 mg kg−1). Moreover, there was a decrease in micronutrients with depth for Fe (from 10.5 to 8.0 mg kg−1), Zn (from 4.0 to 3.7 mg kg−1), Mn (22.0 to 17.2 mg kg−1), and Cu (from 2.1 to 1.7 mg kg−1). Higher micronutrient concentration after green bean crop harvest was related to the highest organic matter content, with the following values for Fe (12.3 mg kg−1), Zn (4.0 mg kg−1), Mn (23.6 mg kg−1), and Cu (2.0 mg kg−1) in the soil profile. The fertigation management of the crop did not modify the micronutrient concentrations in distance in the sand layer due to the reduced exchange capacity of the sand with micronutrients.

Metals and micronutrients in some edible crops and their cultivation soils in eastern-central region of Tunisia: A comparison between organic and conventional farming

In the present study, we evaluated the concentrations of several micronutrients and heavy metals (Fe, Mg, Mn, K, Ca, Na, Zn, Cu, Ni and Cd) in soils and in edible parts of two vegetables (Solanum lycopersicum cv. Amal) and (Lactuca sativa L. cv Augusta) and a fruit (Fragaria x ananassa cv. Sabrina) from conventional and organic farming in the eastern-central region of Tunisia. A principal component analysis (PCA) was conducted to investigate correlations between metals in the edible part of the crops and metals in soil. The bio-concentration factors (BCF) were calculated to evaluate the ability of plants to absorb nutrients from the soil. Our data indicated a significant decrease in micronutrients in the edible part of crops from organic farming. However, toxic metals loads significantly increased in crops from conventional agriculture. Our data should be carefully considered in view of the potential health risk assessment for Tunisian consumers.

Age-related synapse loss in hippocampal CA3 is not reversed by caloric restriction

Caloric restriction (CR) is a reduction of total caloric intake without a decrease in micronutrients or a disproportionate reduction of any one dietary component. While CR attenuates age-related cognitive deficits in tasks of hippocampal-dependent memory, the cellular mechanisms by which CR improves this cognitive decline are poorly understood. Previously, we have reported age-related decreases in key synaptic proteins in the CA3 region of the hippocampus that are stabilized by lifelong CR. In the present study, we examined possible age-related changes in the functional microcircuitry of the synapses in the stratum lacunosum-moleculare (SL-M) of the CA3 region of the hippocampus, and whether lifelong CR might prevent these age-related alterations. We used serial electron microscopy to reconstruct and classify SL-M synapses and their postsynaptic spines. We analyzed synapse number and size as well as spine surface area and volume in young (10 months) and old (29 months) ad libitum fed rats and in old rats that were calorically restricted from 4 months of age. We limited our analysis to SL-M because previous work demonstrated age-related decreases in synaptophysin confined to this specific layer and region of the hippocampus. The results revealed an age-related decrease in macular axo-spinous synapses that was not reversed by CR that occurred in the absence of changes in the size of synapses or spines. Thus, the benefits of CR for CA3 function and synaptic plasticity may involve other biological effects including the stabilization of synaptic proteins levels in the face of age-related synapse loss.

Caloric restriction and age affect synaptic proteins in hippocampal CA3 and spatial learning ability

Caloric restriction (CR) is a daily reduction of total caloric intake without a decrease in micronutrients or disproportionate reduction of any one dietary component. CR can increase lifespan reliably in a wide range of species and appears to counteract some aspects of the aging process throughout the body. The effects on the brain are less clear, but moderate CR seems to attenuate age-related cognitive decline. Thus, we determined the effects of age and CR on key synaptic proteins in the CA3 region of the hippocampus and whether these changes were correlated with differences in behavior on a hippocampal-dependent learning and memory task. We observed an overall, age-related decline in the NR1, N2A and N2B subunits of the N-methyl- d-aspartate (NMDA)-type and the GluR1 and GluR2 subunits of the alpha-amino-3-hydroxy-5-methyl-4-isoxazole proprionic acid (AMPA)-type ionotropic glutamate receptors. Interestingly, we found that CR initially lowers the glutamate receptor subunit levels as compared to young AL animals, and then stabilizes the levels across lifespan. Synaptophysin, a presynaptic vesicle protein, showed a similar pattern. We also found that both CR and ad libitum (AL) fed animals exhibited age-related cognitive decline on the Morris water maze task. However, AL animals declined between young and middle age, and between middle age and old, whereas CR rats only declined between young and middle age. Thus, the decrease in key synaptic proteins in CA3 and cognitive decline occurring across lifespan are stabilized by CR. This age-related decrease and CR-induced stabilization are likely to affect CA3 synaptic plasticity and, as a result, hippocampal function.