Experimental evolution of post-ingestive nutritional compensation in response to a nutrient-poor diet

The geometric framework of nutrition predicts that populations restricted to a single imbalanced diet should evolve post-ingestive nutritional compensation mechanisms bringing the blend of assimilated nutrients closer to physiological optimum. The evolution of such nutritional compensation is thought to be mainly driven by the ratios of major nutrients rather than overall nutritional content of the diet. We report experimental evolution of divergence in post-ingestive nutritional compensation in populations of Drosophila melanogaster adapted to diets that contained identical imbalanced nutrient ratios but differed in total nutrient concentration. Larvae from ‘Selected’ populations maintained for over 200 generations on a nutrient-poor diet with a 1 : 13.5 protein : carbohydrate ratio showed enhanced assimilation of nitrogen from yeasts and reduced assimilation of carbon from sucrose than ‘Control’ populations evolved on a diet with the same nutrient ratio but fourfold greater nutrient concentration. Compared to the Controls, the Selected larvae also accumulated less triglycerides relative to protein. This implies that the Selected populations evolved a higher assimilation rate of amino acids from the poor imbalanced diet and a lower assimilation of carbohydrates than Controls. Thus, the evolution of nutritional compensation may be driven by changes in total nutrient abundance, even if the ratios of different nutrients remain unchanged.

Enhancement Biosorption of Activated Sludge Process on Heavy Metals: Cadmium (Cd) And Nickel (Ni)

This study focuses on Actived sludge treatment is carried out by a continuous reactor. Merriote tube capacity of 10L with a discharge of 10L/day as an inlet. Next to the 10L volume aeration tank where biological treatment occurs, pH 7 ± 0.2 and DO ≥ 3mg/L are the control variables. COD, Cd and Ni are taken for testing inlet and outlet. Artificial waste is used as an inlet with a nutrient ratio of C: N: P is 100: 5: 1. Seeding stage occurs 13 days to get an MLSS value ≥ 2000mg / L. Acclimatization I for adapting microorganisms to the environment occurred for 27 days and acclimatization II for 11 days as microbial ada ptation to heavy metals. Increasing t h e C / N ratio f ro m 20 to 50 will reduce the efficiency of COD removal from 74.5% to 65.38%, Cd removal from 24.3% to 32.3% and Ni removal 13.8% to 28.5%. Initial metals reduced the efficiency of COD removal at low, middle and high levels by 82.5%, 71.75%, 55.875%, respectively. Initial metals at low, middle, and high levels were obtained Cd removal efficiency of 0%, 52.2%, 32.6% and Ni removal efficiency of 0%, 36.3%, 27%, respectively. Optimal response for COD removal is 68.5% with factor initial metal middle and ratio C/N 50.