L-Tryptophan, is one of the amino acids, also is one of the 9 essential amino acids of human which cannot be synthesized internally by him, microbial production is the main method for obtaining tryptophan for commercial uses. Typical microorganisms used for tryptophan production are E. coli and C. glutamicum. In this study, random mutations is performed on two strains of C. glutamicum to increase tryptophan production, the produced tryptophan measured by bioassay using tryptophan auxotroph E. coli (JW1254-2) strain, the mutations are performed using UV radiation. To detect and compare the difference between the parent strains and the muted strains genetically two molecular markers were used start codon targeted polymorphism (SCoT) and Inter-simple sequence repeats (ISSR). Tryptophan remarkably increased after C. glutamicum mutation to reach 278.4 µg/ml (1257.4% increment) from one mutated strain. Molecular genetics methods showed an ability to distinguish between the two original strains and their mutants and it showed the importance of the mutation by UV radiation for increasing the productivity of the bacteria to tryptophan.

This study aimed to determine the relationship between preharvest treatments by salicylic acid, Larginine and L-tryptophan with fruit quality of pear cv. Le-Conte during cold storage at 0◦C and 9095% RH for 12 weeks followed by shelf life at 22◦C for 12 days. Treatments included L-arginine at 100 and 200 ppm, L-tryptophan at 50 and 100 ppm, salicylic acid at 100 and 200 ppm and water as control, all treatments were sprayed on mature trees until run off twice; at full bloom stage and at initial fruit set stage. All conducted treatments were effective in maintaining fruit quality compared with control. Tryptophan at 100 ppm showed the highest significant TSS values, while salicylic acid at 200 ppm showed the lowest significant TSS values during cold storage and shelf life circumstances. Salicylic acid at 100 and 200 ppm showed the lowest weight loss percentages, salicylic at 200 ppm decreased the rate of decay incidence, showed the lowest significant respiration rates, also it was effective in alleviating core browning. In addition, salicylic acid at 200 ppm significantly maintained firmness of fruits, and showed higher h° value of fruits peel, ascorbic acid concentrations, total phenols content and antioxidant capacity values of LeConte pear fruits. Preharvest treatments by salicylic acid, L-arginine and L-tryptophan positively influenced postharvest fruit quality, salicylic acid at 200 ppm effectively maintained fruit quality during cold storage and shelf life.

A study was conducted to investigate the effects of feeding different levels of threonine and tryptophan on growth performance, some serum parameters and carcass traits of broiler chicks under Egyptian summer conditions. Three hundred and sixty Ross 308, one-day-old broiler chicks were randomly allocated into nine treatments with 4 replicates of 10 chicks each. Three levels of threonine (100, 150 or 200 %) and three levels of tryptophan (100, 150 or 200%) according to dietary requirements for Ross 308 chick's guidebook were used in a factorial design arrangement to obtain nine experimental treatments. Two periodical diets were used (starter phase 1-21 days and finisher phase 22-35 days). Growth performance traits including live body weight (LBW), Body weight gain (BWG), feed consumption (FC) and feed conversion ratio (FCR) were recorded at the end of each week. Carcasses were manually eviscerated and weighed. Components of total protein, albumin, cholesterol, and triglycerides were analyzed by using commercial kits. The results showed that chicks fed diet containing 200 % threonine had an improvement in live body weight, body weight gain and feed conversion ratio. The performance index increased with the addition of threonine and tryptophan in the broiler diets. Serum total protein and globulin concentrations were affected by supplemental threonine and tryptophan. Dietary threonine, tryptophan did not affect serum albumin and triglycerides. Total cholesterol was increased with supplementation of threonine, tryptophan and interaction between them. Chicks fed 100% dietary threonine had the significantly better results in terms of the relative weights of carcass, edible parts and bursa compared to the chicks fed other dietary threonine levels, although tryptophan amino acid had not any significant effect on the above-mentioned traits. Giblets, liver, and heart weights percentage increase with increasing tryptophan level in the broiler diets. The relative weight of gizzard reduced with increasing level of both amino acids in the diets.In this study, it concluded that supplementation of threonine and tryptophan improves productive performance and health status of broiler chicks without imposing any toxicity as all blood components were in normal range.