The Experts below are selected from a list of 276 Experts worldwide ranked by ideXlab platform
Konrad Dabrowski - One of the best experts on this subject based on the ideXlab platform.
-
Optimization of Dipeptide–protein mixtures in experimental diet formulations for rainbow trout (Oncorhynchus mykiss) alevins
Aquaculture, 2006Co-Authors: Bendik F. Terjesen, Kyeong-jun Lee, Yongfang Zhang, Mark L. Failla, Konrad DabrowskiAbstract:Abstract It has previously been shown that diets in which the amino acid portion is based on synthetic Dipeptides result in positive growth of rainbow trout alevins. However, the protein-based diets used as a control performed significantly better. One objective of the present study was to identify a protein–Dipeptide mixture ratio that results in comparable growth to a protein-based control, in alevins over the first 6 weeks of feeding. Seven diets were tested, including the casein–gelatin control, three diets with differing proportions of the casein–gelatin replaced with synthetic Dipeptides (50P, 75P and 100P), one diet based on free amino acids and one reference commercial diet. In the seventh diet, arginine-containing Dipeptides were withdrawn from the 100P Dipeptide-based diet. To evaluate the diets, effects on growth, survival, feed intake and free amino acid (FAA) concentrations in muscle tissues were studied. The results on rainbow trout alevin performance using synthetic Dipeptide (100P)-based diets resulted in a relative growth of 34% of the growth observed when alevins were fed the casein–gelatin control diet. The free amino acid (FAA)-based diet, however, resulted in a negative growth of the alevins. In contrast, a 1:1 ratio of synthetic Dipeptides to casein–gelatin (50P diet) resulted in similar growth as the casein–gelatin control diet fed fish. Furthermore, the 50P diet resulted in a survival that was not significantly different from that found when using a commercial diet, which showed the highest survival. The concentrations of indispensable FAA (IAA) in muscle were with few exceptions similar in the control and 50P group, while the 100P Dipeptide- or free amino acid-based diet fed fish showed lower levels of free IAA in muscle. Alevins fed Dipeptide-based diets without arginine (100P w/o Arg) showed high mortality within 2 weeks and negative or minimal growth. This dietary group was restarted at 2 and 4 weeks, and similar results were obtained. In conclusion, the present study indicates that a 50% replacement of the protein portion with synthetic Dipeptides is an acceptable diet formulation for rainbow trout alevins in terms of growth, survival and muscle levels of indispensable FAA. The effects of arginine-containing Dipeptide withdrawal on fish growth and survival indicates that arginine is an indispensable amino acid in first-feeding alevins, despite their expression of the ornithine–urea cycle and related enzymes that may function in net de novo synthesis of arginine. The synthetic Dipeptide diets used here were able to identify such limiting amino acids and may be further used to re-evaluate indispensable amino acid requirements in fish early life stages characterized with high growth.
-
optimization of Dipeptide protein mixtures in experimental diet formulations for rainbow trout oncorhynchus mykiss alevins
Aquaculture, 2006Co-Authors: Bendik F. Terjesen, Kyeong-jun Lee, Yongfang Zhang, Mark L. Failla, Konrad DabrowskiAbstract:Abstract It has previously been shown that diets in which the amino acid portion is based on synthetic Dipeptides result in positive growth of rainbow trout alevins. However, the protein-based diets used as a control performed significantly better. One objective of the present study was to identify a protein–Dipeptide mixture ratio that results in comparable growth to a protein-based control, in alevins over the first 6 weeks of feeding. Seven diets were tested, including the casein–gelatin control, three diets with differing proportions of the casein–gelatin replaced with synthetic Dipeptides (50P, 75P and 100P), one diet based on free amino acids and one reference commercial diet. In the seventh diet, arginine-containing Dipeptides were withdrawn from the 100P Dipeptide-based diet. To evaluate the diets, effects on growth, survival, feed intake and free amino acid (FAA) concentrations in muscle tissues were studied. The results on rainbow trout alevin performance using synthetic Dipeptide (100P)-based diets resulted in a relative growth of 34% of the growth observed when alevins were fed the casein–gelatin control diet. The free amino acid (FAA)-based diet, however, resulted in a negative growth of the alevins. In contrast, a 1:1 ratio of synthetic Dipeptides to casein–gelatin (50P diet) resulted in similar growth as the casein–gelatin control diet fed fish. Furthermore, the 50P diet resulted in a survival that was not significantly different from that found when using a commercial diet, which showed the highest survival. The concentrations of indispensable FAA (IAA) in muscle were with few exceptions similar in the control and 50P group, while the 100P Dipeptide- or free amino acid-based diet fed fish showed lower levels of free IAA in muscle. Alevins fed Dipeptide-based diets without arginine (100P w/o Arg) showed high mortality within 2 weeks and negative or minimal growth. This dietary group was restarted at 2 and 4 weeks, and similar results were obtained. In conclusion, the present study indicates that a 50% replacement of the protein portion with synthetic Dipeptides is an acceptable diet formulation for rainbow trout alevins in terms of growth, survival and muscle levels of indispensable FAA. The effects of arginine-containing Dipeptide withdrawal on fish growth and survival indicates that arginine is an indispensable amino acid in first-feeding alevins, despite their expression of the ornithine–urea cycle and related enzymes that may function in net de novo synthesis of arginine. The synthetic Dipeptide diets used here were able to identify such limiting amino acids and may be further used to re-evaluate indispensable amino acid requirements in fish early life stages characterized with high growth.
Bendik F. Terjesen - One of the best experts on this subject based on the ideXlab platform.
-
Optimization of Dipeptide–protein mixtures in experimental diet formulations for rainbow trout (Oncorhynchus mykiss) alevins
Aquaculture, 2006Co-Authors: Bendik F. Terjesen, Kyeong-jun Lee, Yongfang Zhang, Mark L. Failla, Konrad DabrowskiAbstract:Abstract It has previously been shown that diets in which the amino acid portion is based on synthetic Dipeptides result in positive growth of rainbow trout alevins. However, the protein-based diets used as a control performed significantly better. One objective of the present study was to identify a protein–Dipeptide mixture ratio that results in comparable growth to a protein-based control, in alevins over the first 6 weeks of feeding. Seven diets were tested, including the casein–gelatin control, three diets with differing proportions of the casein–gelatin replaced with synthetic Dipeptides (50P, 75P and 100P), one diet based on free amino acids and one reference commercial diet. In the seventh diet, arginine-containing Dipeptides were withdrawn from the 100P Dipeptide-based diet. To evaluate the diets, effects on growth, survival, feed intake and free amino acid (FAA) concentrations in muscle tissues were studied. The results on rainbow trout alevin performance using synthetic Dipeptide (100P)-based diets resulted in a relative growth of 34% of the growth observed when alevins were fed the casein–gelatin control diet. The free amino acid (FAA)-based diet, however, resulted in a negative growth of the alevins. In contrast, a 1:1 ratio of synthetic Dipeptides to casein–gelatin (50P diet) resulted in similar growth as the casein–gelatin control diet fed fish. Furthermore, the 50P diet resulted in a survival that was not significantly different from that found when using a commercial diet, which showed the highest survival. The concentrations of indispensable FAA (IAA) in muscle were with few exceptions similar in the control and 50P group, while the 100P Dipeptide- or free amino acid-based diet fed fish showed lower levels of free IAA in muscle. Alevins fed Dipeptide-based diets without arginine (100P w/o Arg) showed high mortality within 2 weeks and negative or minimal growth. This dietary group was restarted at 2 and 4 weeks, and similar results were obtained. In conclusion, the present study indicates that a 50% replacement of the protein portion with synthetic Dipeptides is an acceptable diet formulation for rainbow trout alevins in terms of growth, survival and muscle levels of indispensable FAA. The effects of arginine-containing Dipeptide withdrawal on fish growth and survival indicates that arginine is an indispensable amino acid in first-feeding alevins, despite their expression of the ornithine–urea cycle and related enzymes that may function in net de novo synthesis of arginine. The synthetic Dipeptide diets used here were able to identify such limiting amino acids and may be further used to re-evaluate indispensable amino acid requirements in fish early life stages characterized with high growth.
-
optimization of Dipeptide protein mixtures in experimental diet formulations for rainbow trout oncorhynchus mykiss alevins
Aquaculture, 2006Co-Authors: Bendik F. Terjesen, Kyeong-jun Lee, Yongfang Zhang, Mark L. Failla, Konrad DabrowskiAbstract:Abstract It has previously been shown that diets in which the amino acid portion is based on synthetic Dipeptides result in positive growth of rainbow trout alevins. However, the protein-based diets used as a control performed significantly better. One objective of the present study was to identify a protein–Dipeptide mixture ratio that results in comparable growth to a protein-based control, in alevins over the first 6 weeks of feeding. Seven diets were tested, including the casein–gelatin control, three diets with differing proportions of the casein–gelatin replaced with synthetic Dipeptides (50P, 75P and 100P), one diet based on free amino acids and one reference commercial diet. In the seventh diet, arginine-containing Dipeptides were withdrawn from the 100P Dipeptide-based diet. To evaluate the diets, effects on growth, survival, feed intake and free amino acid (FAA) concentrations in muscle tissues were studied. The results on rainbow trout alevin performance using synthetic Dipeptide (100P)-based diets resulted in a relative growth of 34% of the growth observed when alevins were fed the casein–gelatin control diet. The free amino acid (FAA)-based diet, however, resulted in a negative growth of the alevins. In contrast, a 1:1 ratio of synthetic Dipeptides to casein–gelatin (50P diet) resulted in similar growth as the casein–gelatin control diet fed fish. Furthermore, the 50P diet resulted in a survival that was not significantly different from that found when using a commercial diet, which showed the highest survival. The concentrations of indispensable FAA (IAA) in muscle were with few exceptions similar in the control and 50P group, while the 100P Dipeptide- or free amino acid-based diet fed fish showed lower levels of free IAA in muscle. Alevins fed Dipeptide-based diets without arginine (100P w/o Arg) showed high mortality within 2 weeks and negative or minimal growth. This dietary group was restarted at 2 and 4 weeks, and similar results were obtained. In conclusion, the present study indicates that a 50% replacement of the protein portion with synthetic Dipeptides is an acceptable diet formulation for rainbow trout alevins in terms of growth, survival and muscle levels of indispensable FAA. The effects of arginine-containing Dipeptide withdrawal on fish growth and survival indicates that arginine is an indispensable amino acid in first-feeding alevins, despite their expression of the ornithine–urea cycle and related enzymes that may function in net de novo synthesis of arginine. The synthetic Dipeptide diets used here were able to identify such limiting amino acids and may be further used to re-evaluate indispensable amino acid requirements in fish early life stages characterized with high growth.
Timothy P Curran - One of the best experts on this subject based on the ideXlab platform.
-
A short synthesis of bicyclic Dipeptides corresponding to Xxx-L-Pro Xxx-D-Pro having constrained trans-proline amides.
Organic Letters, 1999Co-Authors: Timothy P Curran, And Lisa A. Marcaurelle, Kathleen M. O'sullivanAbstract:A short synthesis that generates two isomeric bicyclic Dipeptides having constrained, trans-proline amide bonds has been developed. One of these bicyclic Dipeptides corresponds to an Xxx-l-Pro Dipeptide (4), while the other isomer corresponds to an Xxx-d-Pro Dipeptide (5). The two isomers are readily distinguished by their 1H NMR spectra.
-
A short synthesis of bicyclic Dipeptides corresponding to Xxx-L-Pro and Xxx-D-Pro having constrained cis-proline amides
Tetrahedron Letters, 1995Co-Authors: Timothy P Curran, Patrick M McenaneyAbstract:A short synthesis that generates two isomeric bicyclic Dipeptides having constrained, cis-proline amide bonds has been developed. One of these bicyclic Dipeptides corresponds to an Xxx-L-Pro Dipeptide (17), while the other isomer corresponds to an Xxx-D-Pro Dipeptide (18).
Paula Gomes - One of the best experts on this subject based on the ideXlab platform.
-
cyclization activated prodrugs synthesis reactivity and toxicity of Dipeptide esters of paracetamol
Bioorganic & Medicinal Chemistry Letters, 2005Co-Authors: Cledir Santos, Maria Luisa Mateus, Ana Paula Dos Santos, Rui Moreira, Eliandre De Oliveira, Paula GomesAbstract:Dipeptide esters of paracetamol were prepared in high yields. These compounds are quantitatively hydrolyzed to paracetamol and corresponding 2,5-diketopiperazines at pH 7.4 and 37 degrees C. The reactivity is increased in sarcosine and proline peptides and decreased by bulky side chains at both the N- and C-terminal residues of the Dipeptide carrier. Moreover, Dipeptide esters of paracetamol did not affect the levels of hepatic glutathione. Thus, Dipeptides seem promising candidates as carriers for cyclization-activated prodrugs.
-
Cyclization-activated prodrugs. Synthesis, reactivity and toxicity of Dipeptide esters of paracetamol.
Bioorganic & Medicinal Chemistry Letters, 2005Co-Authors: Cledir Santos, Maria Luisa Mateus, Rui Moreira, Eliandre De Oliveira, Ana Paula De Azevedo Dos Santos, Paula GomesAbstract:Dipeptide esters of paracetamol were prepared in high yields. These compounds are quantitatively hydrolyzed to paracetamol and corresponding 2,5-diketopiperazines at pH 7.4 and 37 °C. The reactivity is increased in sarcosine and proline peptides and decreased by bulky side chains at both the N- and C-terminal residues of the Dipeptide carrier. Moreover, Dipeptide esters of paracetamol did not affect the levels of hepatic glutathione. Thus, Dipeptides seem promising candidates as carriers for cyclization-activated prodrugs.
Hui-hsiung Lin - One of the best experts on this subject based on the ideXlab platform.
-
Discovery of Potent Cysteine-Containing Dipeptide Inhibitors against Tyrosinase: A Comprehensive Investigation of 20 × 20 Dipeptides in Inhibiting Dopachrome Formation
Journal of agricultural and food chemistry, 2015Co-Authors: Tien-sheng Tseng, Keng-chang Tsai, Wang-chuan Chen, Yeng-tseng Wang, Yu Ching Lee, Ming-jaw Don, Chang-yu Chang, Ching-hsiao Lee, Hui-hsiung LinAbstract:Tyrosinase is an essential copper-containing enzyme required for melanin synthesis. The overproduction and abnormal accumulation of melanin cause hyperpigmentation and neurodegenerative diseases. Thus, tyrosinase is promising for use in medicine and cosmetics. Our previous study identified a natural product, A5, resembling the structure of the Dipeptide WY and apparently inhibiting tyrosinase. Here, we comprehensively estimated the inhibitory capability of 20 × 20 Dipeptides against mushroom tyrosinase. We found that cysteine-containing Dipeptides, directly blocking the active site of tyrosinase, are highly potent in inhibition; in particular, N-terminal cysteine-containing Dipeptides markedly outperform the C-terminal-containing ones. The cysteine-containing Dipeptides, CE, CS, CY, and CW, show comparative bioactivities, and tyrosine-containing Dipeptides are substrate-like inhibitors. The Dipeptide PD attenuates 16.5% melanin content without any significant cytotoxicity. This study reveals the functional role of cysteine residue positional preference and the selectivity of specific amino acids in cysteine-containing Dipeptides against tyrosinase, aiding in developing skin-whitening products.
-
Discovery of Potent Cysteine-Containing Dipeptide Inhibitors against Tyrosinase: A Comprehensive Investigation of 20 × 20 Dipeptides in Inhibiting Dopachrome Formation
Journal of agricultural and food chemistry, 2015Co-Authors: Tien-sheng Tseng, Keng-chang Tsai, Wang-chuan Chen, Yeng-tseng Wang, Yu Ching Lee, Ming-jaw Don, Chang-yu Chang, Ching-hsiao Lee, Hui-hsiung LinAbstract:Tyrosinase is an essential copper-containing enzyme required for melanin synthesis. The overproduction and abnormal accumulation of melanin cause hyperpigmentation and neurodegenerative diseases. Thus, tyrosinase is promising for use in medicine and cosmetics. Our previous study identified a natural product, A5, resembling the structure of the Dipeptide WY and apparently inhibiting tyrosinase. Here, we comprehensively estimated the inhibitory capability of 20 × 20 Dipeptides against mushroom tyrosinase. We found that cysteine-containing Dipeptides, directly blocking the active site of tyrosinase, are highly potent in inhibition; in particular, N-terminal cysteine-containing Dipeptides markedly outperform the C-terminal-containing ones. The cysteine-containing Dipeptides, CE, CS, CY, and CW, show comparative bioactivities, and tyrosine-containing Dipeptides are substrate-like inhibitors. The Dipeptide PD attenuates 16.5% melanin content without any significant cytotoxicity. This study reveals the functiona...