Amino Acids In Human Nutrition Research Articles

Comparative Transcriptomic Analysis Reveals Diverse Expression Pattern Underlying Fatty Acid Composition among Different Beef Cuts.

Beef is an important dietary source of quality animal proteins and amino acids in human nutrition. The fatty acid composition is one of the indispensable indicators affecting nutritional value of beef. However, a comprehensive understanding of the expression changes underlying fatty acid composition in representative beef cuts is needed in cattle. This study aimed to characterize the dynamics of fatty acid composition using comparative transcriptomic analysis in five different type of beef cuts. We identified 7545 differentially expressed genes (DEGs) among 10 pair-wise comparisons. Co-expression gene network analysis identified two modules, which were significantly correlated with 2 and 20 fatty acid composition, respectively. We also identified 38 candidate genes, and functional enrichment showed that these genes were involved in fatty acid biosynthetic process and degradation, PPAR, and AMPK signaling pathway. Moreover, we observed a cluster of DEGs (e.g., SCD, LPL, FABP3, and PPARD) which were involved in the regulation of lipid metabolism and adipocyte differentiation. Our results provide some valuable insights into understanding the transcriptome regulation of candidate genes on fatty acid composition of beef cuts, and our findings may facilitate the designs of genetic selection program for beneficial fatty acid composition in beef cattle.

4. Metabolism and applicationsof functional amino acids in human nutrition

4. Metabolism and applicationsof functional amino acids in human nutrition

International Regulations on Amino Acid Use in Foods and Supplements and Recommendations to Control Their Safety Based on Purity and Quality

We examined international regulatory developments related to the use of proteinogenic amino acids in human nutrition and concluded that the current risk-assessment practices tend to focus exclusively on setting maximum daily limits. In this brief review we argue that controlling the standards of purity and ingredient quality are the key safety issues that should be considered during risk assessment. Moreover, if maximum intake limits on amino acids are implemented, they should be defined using a well-established rationale for the health risks associated with high intakes. This would avoid setting limits that are so low that they render the dietary supplements ineffective and which, therefore, could mislead the consumer. We further suggest that there should be greater regional concordance in how the use of amino acids as ingredients is regulated and use the capacity of industry to oversee pre-competitive issues, such as standards of purity and scientific research on the safety of generic ingredients. Our arguments are based on clinical safety scientific research and oversights of amino acid purity standards conducted in the last decade by the not-for-profit international association, the International Council on Amino Acid Science.

Application of carboxylic acid-functionalized of graphene oxide for electrochemical simultaneous determination of tryptophan and tyrosine in milk

In this work, a new method for the simultaneous determination of tryptophan (Trp) and tyrosine (Tyr) in milk has been reported. Trp and Tyr are essential amino acids in human nutrition, but their electrochemical signal overlapped. For solve this problem, we developed modified Screen Printed Carbon Electrode (SPCE) with Graphene Oxide–COOH/Chitosan (GO–COOH/Chitosan) electro-deposition. The morphology and electrochemical performance of modified electrode were characterized by scanning electron microscopy, energy dispersive spectrometry, FT-IR, electrochemical impedance spectroscopy and cyclic voltammetry. The electrochemical simultaneous determination of Trp and Tyr has been investigated by using differential pulse voltammetry. The carboxylic acid functionalized GO modified SPCE was utilized to catalyze the oxidation of Trp and Tyr. Compared with SPCE/GO/Chitosan and SPCE/Chitosan sensor, the new sensor has enhanced sensitivity, low detection limit and high selectivity. In addition, the SPCE/GO–COOH–Chitosan sensor enhanced separation of the oxidation peak of Tyr and Trp and showed a remarkable increase in peak current for electro-active compounds, thus, it can be used for simultaneous voltammetric determination. Under the optimized experimental conditions, a linear correlation between oxidation peak current and concentration of Tyr and Trp in the ranges 0.1–60 µM and 0.4–40 µM with a detection limit of 0.05 µM (S/N = 3) and 0.1 µM (S/N = 3) were achieved, respectively. Finally, the proposed electrochemical sensor was applied for quantification of Tyr and Trp in milk samples, where standard solutions were spiked to the milk samples and recoveries were obtained.

Dietary Requirements for Proteins and Amino Acids in Human Nutrition

Background: An optimal dietary Amino Acid (AA) intake is necessary for the growth of body proteins. A new method for protein quality evaluation called Digestible Indispensable AA Score (DIAAS) was established. Despite that the information about dietary AA requirements are available for different stages of life, in practical conditions, most people deal only with the dietary proteins, if ever. Objective: The aim of this mini-review was to analyze the protein quality of protein sources by DIAAS and to find AA and protein dietary requirements in human nutrition. Methods: A literature research was performed using the keyword “amino acid”, “diet”, “nutrition”, “human”, “muscle” and “requirement” individually or all together, in Scopus, Web of Science and Pubmed. Results: The optimum amount of dietary AA is necessary for AA utilization in the body and is limited by AA which is present in the lowest amount; the surplus of other AA is not utilized in the body. Food and Agriculture Organization reported requirements for dietary protein and AA intake for infants, children, however for adults (over 18) for maintenance. Most of the studies which are dealing with the dietary AA requirements in sports nutrition are aimed at the blends of AA and for branched-chain AA. Concerning the protein quality, at this time, there is little information about the protein quality evaluated by DIAAS method. Conclusion: Dietary intake of high-quality protein or a blend of different proteins will provide all AA to the body. However, studies on protein quality evaluation by DIAAS method are necessary to perform.

Construction of poly-met DNA yeast hybrids for increased methionine content: technofunctional properties of the hybrid yeasts.

Methionine is a limiting essential amino acid in human nutrition, to overcome the possible overdosage and improve bioavailability methionine supply should be in protein bound form. So insertion a poly-met encoding DNA sequence results a more efficient solution in increasing methionine content of yeast. Poly-met DNA yeast hybrids were constructed of Saccharomyces cerevisiae CB89, an auxotrophic mutant strain. Synthetic DNA sequence encoding methionine polypeptide was inserted into the polylinker region of pVT-U 100 vector with 2 mu plasmid replicon. After transformation of E. coli HB101 cells the efficiency of the ligation and transformation was checked by digesting the minipreps. S. cerevisiae CB89 was transformed with vector-poly-met insert and with the plasmid vector only as well. Hybrid yeasts were selected on uracilless medium. PVT-U 100 can be used as vector for the expression of DNA sequence in S. cerevisiae. The vector harbours the promoter of ADC1 gene immediately downstream from the promoter lies a polylinker sequence comprising unique restriction enzyme sites for BamHI, HindIII, PvuII, SacI, Xhol. The polylinker sequence is followed by the transcriptional stop site and polyadenylation signal of ADC1 gene. Plasmid pVT-U 100 has selection markers for S. cerevisiae (URA3) and for E. coli (amp, per F). Results show that the poly-met DNA hybrids methionine content is influenced by the length of the insert. Fusion hybrids containing 600 bp oligo insert showed the best values. Distribution of methionine content in the protein subfractions of polymet DNA hybrid and parent strain CB89 was determined in dependence of glucose concentration and aeration intensity. The increase in synthesized methionine appeared in fractions 1 + 2 and residue. Technofunctional properties of parent strains and hybrids were compared for whole cells and cell wall (residue). Results demonstrate that enrichment in methionine in the cell wall fraction resulted improvement of emulsifying ability. Bioavailability of methionine content was better in DNA hybrid yeast than in parent strain and was the best when propagated in whey medium.

Application of neural networks to lysine production

Lysine is an essential amino acid in human nutrition and also widely used in animal feed formulations. It is produced on a large scale by fermentation in stirred tank bioreactors. In the present work lysine was produced by fed-batch fermentation with an industrial Brevibacterium flavum strain grown in a 115 m 3 fermentor on a beet molasses based medium. The difficulties in on-line monitoring of substrate consumption and of product formation complicate real-time process control. We demonstrate that well-trained backpropagation multilayer neural networks can be employed to overcome such problems without detailed prior knowledge of the relationships of process variables under investigation. Neural network models programmed in MS-Visual C++ for Windows and implemented on a personal computer were constructed and applied to state estimation and multi-step-ahead prediction of consumed sugar and produced lysine on the basis of on-line measurable variables for process control purposes.

Neural state estimation and prediction in amino acid fermentation

On-line control of amino acid fermentations is complicated by uncertainties typical of biological processes and by difficulties in real-time monitoring of key process variables. Lysine is an essential amino acid in human nutrition, and also widely used in animal feed formulations. The paper discusses the construction and application of feed-forward, back-propagation neural networks as software ‘sensors’ in state estimation, and multi-step ahead prediction of produced lysine and consumed sugar. Neural networks were programmed in MS Visual C++ for Windows for implementation in a PC, with a userfriendly interface for convenience and ease of operation. It is demonstrated that a well trained neural network of optimal architecture can be succesfsully used in control of amino acid production

L-tryptophan and depressive illness: a valuable adjunct to therapy?

L-tryptophan is an essential amino acid in human nutrition. The minimum daily requirement for adults is in the range of 175 to 250 mg daily and this is normally exceeded in the average western diet which contains 600 to 1000 mg. Excess tryptophan is normally metabolised through the kynurenine pathway and only 1–2% of tryptophan in the diet is converted to 5-HT. The concept that 5-HT had a part to play in depressive illness evolved after the original observation by Ashcroft & Sharman in 1960 that patients with severe depressive illness had lower levels of the metabolite of 5-HT in cerebrospinal fluid compared with controls. In addition, early papers on the therapeutic efficacy of tryptophan suggested that it was potentially as successful as ECT.

Role of Amino Acids in Human Nutrition

The FASEB JournalVolume 6, Issue 6 p. 2361-2362 50 Years Ago Role of Amino Acids in Human Nutrition Julius E. Johnson, Julius E. JohnsonSearch for more papers by this authorWilliam J. Haines, Corresponding Author William J. Haines n/a@.dne Correspondence may be addressed to Dr. Haines, 5 Bedford Dr., RD #2, Doylestown, PA 18901, USA, and/or to Dr. Johnson, 1111 Knollwood Ct., Midland, MI 48640, USA.Search for more papers by this author Julius E. Johnson, Julius E. JohnsonSearch for more papers by this authorWilliam J. Haines, Corresponding Author William J. Haines n/a@.dne Correspondence may be addressed to Dr. Haines, 5 Bedford Dr., RD #2, Doylestown, PA 18901, USA, and/or to Dr. Johnson, 1111 Knollwood Ct., Midland, MI 48640, USA.Search for more papers by this author First published: 01 March 1992 https://doi.org/10.1096/fasebj.6.6.1544546AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume6, Issue6March 1992Pages 2361-2362 RelatedInformation

Requirements for Growth of Single Human Cells

The experiments reported in this paper may foreshadow a change in the traditional concept of so-called essential amino acids in human nutrition. It has been shown that a number of strains of single types of human cells may be propagated serially in a medium containing 13 "essential" amino acids along with other ingredients when a relatively large inoculum of cells is employed. In the present experiments it was learned that this medium did not permit successful propagation if relatively small inocula of cells were used, unless additional amino acids not included in the original medium, were added. The efficiency of the medium in promoting growth in the case of lighter inocula was restored when seven amino acids, not required for optimal growth with heavy inocula, were added to the basal medium. Serine was the most important of the seven non-essential amino acids that were not required in the medium to support optimal growth with heavy inocula. Thus the essentiality or non-essentiality of an amino acid may depend upon the capacity of the number of cells involved to meet the requirements for amino acids by biosynthesis within the cells, as may be determined by the population of cells and their rate of growth.