Molecular Frameworks of Nitrogen Response in Plants: A Review

Nitrogen is a crucial element for all living organisms especially plants which rely on substantial nitrogen quantities to sustain their growth and productivity. Crop production is greatly influenced by nitrogen consumption efficiency and a significant amount of nitrogen fertilizers is used to increase yield. Approximately half of N fertilizers are not utilized by the crops and are lost to the environment by polluting water sources or by releasing pollutants into the atmosphere. From the rhizosphere, plants absorb nitrogen in the form of nitrate (NO3-), ammonium (NH4+), or organic nitrogen (amino acids and urea). Plants exhibit an array of sensing and adaptive mechanisms to respond to the diverse nitrogen nutrition conditions which include morphological and physiological responses. Two primary systems govern nitrogen uptake in plants: the High-affinity transport system (HATS) and the Low-affinity transport system (LATS). Nitrate transporters fall into two categories, Nitrate Transporter 1 (NRT1) and Nitrate Transporter 2 (NRT2) transporters, Chloride Channel Family (CLC) transporters and Slow Anion Associated Channel Homologs (SLAC/SLAHs). The ammonium transporter family includes Ammonium Transporter 1 (AMT1) and Ammonium Transporter 2 (AMT2) transporters. The uptake of organic nitrogen is facilitated through amino acid and urea uptake and transport systems. In fluctuating environmental conditions, plants employ nitrogen response mechanisms to fine-tune homeostasis. A comprehensive understanding of these regulatory mechanisms holds the potential to yield valuable insights for the development of crops with enhanced nitrogen use efficiency.

Effect of oral curcumin administration on serum peroxides and cholesterol levels in human volunteers.

The effect of curcumin administration in reducing the serum levels of cholesterol and lipid peroxides was studied in ten healthy human volunteers, receiving 500 mg of curcumin per day for 7 days. A significant decrease in the level of serum lipid peroxides (33%), increase in HDL Cholesterol (29%), and a decrease in total serum cholesterol (11.63%) were noted. As curcumin reduced serum lipid peroxides and serum cholesterol, the study of curcumin as a chemopreventive substance against arterial diseases is suggested.

Inhibition of lipid peroxidation and cholesterol levels in mice by curcumin.

Effect of oral administration of curcumin (diferuloyl methane) on lipid peroxidation in various organs of mice like liver, lung, kidney and brain was studied in control animals as well as those given carbon tetrachloride, paraquat and cyclophosphamide. Oral administration of curcumin significantly lowered the increased peroxidation of lipids in these tissues produced by these chemicals. Administration of curcumin was also found to lower significantly the serum and tissue cholesterol levels in these animals, indicating that the use of curcumin helps in conditions associated with peroxide induced injury such as liver damage and arterial diseases.