In Prokaryotes gene expression modifies according to the changes in the nutritional status. Unicellular organisms or single cell organisms adjust their metabolic rate in response to nutrient supply or availability. For example lactose, histidine and tryptiphane operons are controlled by the availability of their respective substrates.
In multi-cellular organisms, the expression of gene differs from that of a single cell organism, and involves hormonal, neural and also nutritional factor interactions. Nutrients play a major role in regulation of expression of genes in mammals. The response to a nutrient deficiency or availability induces different gene expression, which is specific to each genotype.
Nutrition and Gene Regulation:
New genomic technologies are used to study the effect of nutrition on gene regulation, such as influence of nutrients, micronutrients and also phytochemicals on carcinogenesis pathway.
Study of Nutrient -Modulated Carcinogenesis (Cancer)?:
1. Study of influence of nutrients on mechanisms such as DNA damage and DNA repair
2. Study of DNA methylation and its influence on gene expression and also phenotype expression.
3. Study involves rearranging antioxidant and oxidative stress, and signalling pathway along with specific target receptors
4. Study of ell cycle check points, apoptosis process and antiangiogenesis and much more.
Effect of Nutrient Carbohydrate on Gene Expression:
Feeding high-energy diet leads to early onset of obesity, and metabolic disorders in rats, due to inability to cope with high energy diet. Obesity is also a result of decreased gene expression of oxygenic neuropeptides, neuropeptides Y (NPY), and Agouti Related Peptide (Ag RP) and many more. Hyperglycemia also activated and increased almost three folds the expression of angiotensinogen (AGT) in liver
Most common and abundantly found carbohydrate is glucose, it is used to study the influence of nutrients on the gene expression. Mammals show a complex effect in response to the availability of dietary glucose, because it combines effects such as metabolism of glucose and its effect on hormonal regulation, such as stimulation of insulin production and secretion and inhibition of glucagon secretion in pancreas.
Carbohydrate glucose, along with insulin induces the activation of genes, which codes for glucose transporters and glycolytic enzymes and lipogenic enzymes in the liver. For example presence of insulin and glucose activates L-type pyruvate kinase (L-PK), acetyl-CoA carboxylase (ACC), and fatty acid syntase and represses expression of genes involved in gluconeogenic pathway, such as phosphoenolpyruvate carboxykinase gene. This shows that carbohydrate for example glucose also play a major and important role in the gene regulation or transcriptional regulation of genes.
Not just carbohydrate but also proteins (amino acids), minerals, vitamins and fats like monounsaturated fatty acid, saturated fatty acid and PUFA (poly unsaturated fatty acid) also play a very important role in the expression of gene. Excess availability or deficiency of these nutritional factors alters the gene regulation or in other words induces the some kind of disease or deficiency in humans or living organisms.
1. Nutrigenomics can be integrated with data bases of genomic sequences, and inter individual genetic variability disease susceptibility
2. By using this integrated data bases, we can understand the role of nutrients in life threatening conditions such as cancer, cardiovascular disease, hypertension and much more
Study and research in nutrigenomics may help in developing food products, which may have the capacity to prevent or reduce onset and impact of complex diseases. For example type 2 diabetes or may be some kind of cancers.
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