scholarly journals Multiple Amino Acids Inhibit Postharvest Senescence of Broccoli

Horticulturae ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 71
Author(s):  
Muhammad Sohail ◽  
Ron Baden Howe Wills ◽  
Michael C. Bowyer ◽  
Penta Pristijono
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Respiration Rate ◽  
Ethylene Production ◽  
Free Amino ◽  
Ion Leakage ◽  
Delayed Senescence ◽  
Naturally Occurring ◽  
Synthetic Chemicals ◽  
Postharvest Senescence

The function of free amino acids in protein synthesis, as a source of energy and unique roles in catabolism have been well studied in plant development but their function in postharvest fruit and vegetables has received little attention. This study evaluated 11 amino acids—arginine, alanine, aspartic acid, glutamic acid, glycine, ornithine, phenylalanine, serine, tyrosine, tryptophan and valine—on the development of senescence of broccoli. Broccoli florets were dipped in 5 mM solution of amino acids, then stored at 10 °C in air containing 0.1 µL L−1 ethylene. Senescence was assessed by green life, ethylene production, respiration rate and ion leakage. Green life was increased by all the amino acids except valine. Similarly, ethylene production and ion leakage were decreased by all the amino acids except valine, while respiration rate was reduced by all amino acids. It is speculated that the early reduction in ethylene production could be the mechanism by which the amino acids delayed senescence. The beneficial effect of naturally occurring amino acids in inhibiting senescence has potential commercial relevance, as the amino acids have Generally Recognised As Safe (GRAS) status which should assist gain regulatory approval, and gain acceptance by consumers wary of synthetic chemicals on foods.

scholarly journals Destruxin A Interacts with Aminoacyl tRNA Synthases in Bombyx mori

2021 ◽  
Vol 7 (8) ◽  
pp. 593
Author(s):  
Jingjing Wang ◽  
Alexander Berestetskiy ◽  
Qiongbo Hu
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Bombyx Mori ◽  
Metarhizium Anisopliae ◽  
Free Amino ◽  
Molecular Target ◽  
Trna Synthetases ◽  
Interaction Mode ◽  
Aminoacyl Trna Synthetases ◽  
Wide Range

Destruxin A (DA), a hexa-cyclodepsipeptidic mycotoxin produced by the entomopathogenic fungus Metarhizium anisopliae, exhibits insecticidal activities in a wide range of pests and is known as an innate immunity inhibitor. However, its mechanism of action requires further investigation. In this research, the interactions of DA with the six aminoacyl tRNA synthetases (ARSs) of Bombyx mori, BmAlaRS, BmCysRS, BmMetRS, BmValRS, BmIleRS, and BmGluProRS, were analyzed. The six ARSs were expressed and purified. The BLI (biolayer interferometry) results indicated that DA binds these ARSs with the affinity indices (KD) of 10−4 to 10−5 M. The molecular docking suggested a similar interaction mode of DA with ARSs, whereby DA settled into a pocket through hydrogen bonds with Asn, Arg, His, Lys, and Tyr of ARSs. Furthermore, DA treatments decreased the contents of soluble protein and free amino acids in Bm12 cells, which suggested that DA impedes protein synthesis. Lastly, the ARSs in Bm12 cells were all downregulated by DA stress. This study sheds light on exploring and answering the molecular target of DA against target insects.

scholarly journals Amino acid regulation of synthesis of ribonucleic acid and protein in the liver of rats

1971 ◽  
Vol 124 (2) ◽  
pp. 385-392 ◽  
Author(s):  
R. W. Wannemacher ◽  
C. F. Wannemacher ◽  
M. B. Yatvin
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Free Amino Acids ◽  
Free Amino ◽  
Cellular Protein ◽  
Deficient Diet ◽  
Cellular Protein Content ◽  
Regulate Protein

Weanling (23-day-old) rats were fed on either a low-protein diet (6% casein) or a diet containing an adequate amount of protein (18% casein) for 28 days. Hepatic cells from animals fed on the deficient diet were characterized by markedly lower concentrations of protein and RNA in all cellular fractions as compared with cells from control rats. The bound rRNA fraction was decreased to the greatest degree, whereas the free ribosomal concentrations were only slightly less than in control animals. A good correlation was observed between the rate of hepatic protein synthesis in vivo and the cellular protein content of the liver. Rates of protein synthesis both in vivo and in vitro were directly correlated with the hepatic concentration of individual free amino acids that are essential for protein synthesis. The decreased protein-synthetic ability of the ribosomes from the liver of protein-deprived rats was related to a decrease in the number of active ribosomes and heavy polyribosomes. The lower ribosomal content of the hepatocytes was correlated with the decreased concentration of essential free amino acids. In the protein-deprived rats, the rate of accumulation of newly synthesized cytoplasmic rRNA was markedly decreased compared with control animals. From these results it was concluded that amino acids regulate protein synthesis (1) by affecting the number of ribosomes that actively synthesize protein and (2) by inhibiting the rate of synthesis of new ribosomes. Both of these processes may involve the synthesis of proteins with a rapid rate of turnover.

scholarly journals Pinocytosis and intracellular degradation of exogenous protein: modulation by amino acids.

1983 ◽  
Vol 96 (6) ◽  
pp. 1586-1591 ◽  
Author(s):  
J M Besterman ◽  
J A Airhart ◽  
R B Low ◽  
D E Rannels
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Free Amino Acids ◽  
Free Amino ◽  
De Novo ◽  
Serum Proteins ◽  
Fluid Phase ◽  
Cellular Protein ◽  
Intracellular Degradation ◽  
Exogenous Protein

Intracellular degradation of exogenous (serum) proteins provides a source of amino acids for cellular protein synthesis. Pinocytosis serves as the mechanism for delivering exogenous protein to the lysosomes, the major site of intracellular degradation of exogenous protein. To determine whether the availability of extracellular free amino acids altered pinocytic function, we incubated monolayers of pulmonary alveolar macrophages with the fluid-phase marker, [14C]sucrose, and we dissected the pinocytic process by kinetic analysis. Additionally, intracellular degradation of endogenous and exogenous protein was monitored by measuring phenylalanine released from the cell monolayers in the presence of cycloheximide. Results revealed that in response to a subphysiological level of essential amino acids or to amino acid deprivation, (a) the rate of fluid-phase pinocytosis increased in such a manner as to preferentially increase both delivery to and size of an intracellular compartment believed to be the lysosomes, (b) the degradation of exogenously supplied albumin increased, and (c) the fraction of phenylalanine derived from degradation of exogenous albumin and reutilized for de novo protein synthesis increased. Thus, modulation of the pinosome-lysosome pathway may represent a homeostatic mechanism sensitive to the availability of extracellular free amino acids.

scholarly journals The specific radioactivity of the precursor pool for estimates of the rate of protein synthesis (Short Communication)

1973 ◽  
Vol 134 (4) ◽  
pp. 1127-1130 ◽  
Author(s):  
Edward B. Fern ◽  
Peter J. Garlick
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Free Amino Acids ◽  
Free Amino ◽  
Short Communication ◽  
Specific Radioactivity ◽  
Precursor Pool

Infusion of rats with [U-14C]glycine resulted in labelling of glycine and serine in tissue proteins. The pattern of labelling in protein more nearly resembled that of the free amino acids in the tissue than in the plasma.

scholarly journals The relationship between placental protein synthesis and transfer of amino acids

1983 ◽  
Vol 210 (1) ◽  
pp. 99-105 ◽  
Author(s):  
M J Carroll ◽  
M Young
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Guinea Pig ◽  
Specific Radioactivity ◽  
Protein Amino Acid ◽  
Naturally Occurring ◽  
Placental Protein ◽  
The Relationship ◽  
Radioactivity Measurements

The relationship between placental protein synthesis and transfer of amino acids from mother to foetus was studied in the guinea pig, by using [U-14C]-lysine, -leucine, -glycine, -aspartate and -alpha-aminoisobutyrate. The uptake of label by protein was 12-16% of total label transferred. Cycloheximide inhibited incorporation of all naturally occurring amino acids into protein by 81-96% and transfer by 62-75%; the concentration of label in the free pool was increased for each. These findings were confirmed when specific-radioactivity measurements were made with L-[U-14C]lysine. The transfer of the non-protein amino acid alpha-aminoisobutyrate was not significantly decreased by cycloheximide. A model, linking protein synthesis to the generation of a transfer pool of amino acids, is proposed whereby inhibition of protein synthesis decreases the amount of amino acid available for transfer.

Autoradiographische Untersuchungen zur Proteinsynthese während der Frühentwicklung von Dermestes frischi (Coleoptera) / Autoradiographic Investigations on Protein Synthesis During Early Development of Dermestes frischi (Coleoptera)

1972 ◽  
Vol 27 (2) ◽  
pp. 193-195 ◽  
Author(s):  
H. W. Küthe
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Early Development ◽  
Free Amino Acids ◽  
Free Amino ◽  
Protein Fractions ◽  
Cleavage Stages ◽  
Cortical Regions

Injection of tritiated phenylalanine or leucine in eggs shortly after deposition shows the importance and use of free amino acids during cleavage stages. First the activity is found homogeneously distributed in the yolk system and ooplasm. In late cleavage stages the amino acids are incorporated into the periplasm of the egg. These results lead to the conclusions, that there is a continuous transfer of material out of the yolk system into cortical regions during cleavage. Secondly the first new synthetized protein fractions are located in the cortical ooplasm.

scholarly journals Ingestion of Free Amino Acids as Opposed to Intact Protein Increases Amino Acid Absorption but Does Not Further Augment Postprandial Muscle Protein Synthesis Rates

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 673-673
Author(s):  
Michelle E G Weijzen ◽  
Rob JJ van Gassel ◽  
Imre W K Kouw ◽  
Stefan H M Gorissen ◽  
Marcel CG van de Poll ◽  
...  
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Protein Digestion ◽  
Acid Absorption ◽  
Amino Acid Absorption

Abstract Objectives The rate of protein digestion and amino acid absorption determines the postprandial rise in circulating amino acids and, as such, modulates postprandial muscle protein synthesis rates. This study compares protein digestion and amino acid absorption kinetics and the subsequent muscle protein synthetic response following ingestion of intact protein versus an equivalent amount of free, crystalline amino acids. Methods Twenty-four healthy, young subjects (age: 22 ± 3 y, BMI: 23 ± 2 kg·m−2, sex: 12 M/12F) ingested 30 g intrinsically L-[1–13C]-phenylalanine and L-[1–13C]-leucine labeled milk protein (PROT; n = 12) or an equivalent amount of free amino acids (AA; n = 12). In addition, subjects received primed continuous L-[ring-2H5]-phenylalanine, L-[ring-3,5–2H2]-tyrosine, and L-[1–13C]-leucine infusions. Blood samples and muscle biopsies were obtained frequently to assess protein digestion and amino acid absorption kinetics and subsequent muscle protein synthesis rates over a 6 h postprandial period. An unpaired t-test was used to compare overall exogenous phenylalanine release in plasma. For other parameters repeated measures ANOVA were applied to determine differences between groups over time (time as within, and group as between-subjects factor). Data are expressed as mean ± SD. Results Postprandial plasma amino acid concentrations and exogenous phenylalanine appearance rates increased after ingestion of PROT and AA (both, P < 0.001), with a greater increase following ingestion of AA when compared to PROT (time*group interaction P < 0.001). Exogenous phenylalanine release in plasma assessed over the 6 h postprandial period, was greater in AA (76 ± 9%) compared with PROT (59 ± 10%; P < 0.001). Ingestion of AA and PROT strongly increased muscle protein synthesis rates based upon L-[ring-2H5]-phenylalanine (time effect P < 0.001), with no differences between groups (from 0.037 ± 0.015 to 0.053 ± 0.014%·h−1 and from 0.039 ± 0.016 to 0.051 ± 0.010%·h−1, respectively; time*group interaction P = 0.629). Conclusions Ingestion of free amino acids as opposed to intact milk protein is followed by more rapid amino acid absorption and greater postprandial plasma amino acid availability, but this does not further augment postprandial muscle protein synthesis rates. Funding Sources This research did not receive external funding.

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