scholarly journals Nitrosation and analysis of amino acid derivatives by isocratic HPLC

RSC Advances ◽  
2016 ◽  
Vol 6 (16) ◽  
pp. 13120-13128 ◽  
Author(s):  
Songül Ulusoy ◽  
Halil Ibrahim Ulusoy ◽  
Daniel Pleissner ◽  
Niels Thomas Eriksen
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Acid Concentration ◽  
Amino Acid Concentration ◽  
Amino Acid Derivatives ◽  
Hydroxy Acids ◽  
Isocratic Hplc

Amino acids are transformed by nitrosation with dinitrogen trioxide into their corresponding α-hydroxy acids, which are separated and analysed by HPLC, and used to quantify the original amino acid concentration in samples.

Nutritional factors associated with seasonal population increase of cacao thrips, Selenothrips rubrocinctus (Giard) (Thysanoptera), on cashew, Anacardium occidentale

1963 ◽  
Vol 53 (4) ◽  
pp. 681-713 ◽  
Author(s):  
R. G. Fennah
Keyword(s):  
Amino Acids ◽  
Water Stress ◽  
Amino Acid ◽  
Acid Concentration ◽  
Leaf Tissue ◽  
The Other ◽  
Amino Acid Concentration ◽  
Population Increase ◽  
Bearing Surface ◽  
Wet Season

The feeding of the cacao thrips, Selenothrips rubrocinctus (Giard), on cashew, Anacardium occidentale, one of its host plants in Trinidad, West Indies, is considered in relation to the annual period of maximum population increase on this host and to the choice of feeding sites on individual leaves. On trees observed for three years, populations regularly increased during the dry season, from a low level in December and January to a peak in April or May, and then rapidly declined during the wet season. Even when thrips were most abundant, some trees were free from attack, and this could not be attributed to protective morphological features, to specific repellent substances in the leaf, or to chance. S. rubrocinctus was found to feed on leaves that were subjected to water-stress and to breed only on debilitated trees: the evidence suggested that the adequacy of its supply of nutrients depends on the induction of suitable metabolic conditions within the leaf by water-stress.Both nymphs and adults normally feed on the lower, stomata-bearing surface of the leaf, but in a very humid atmosphere only a weak preference is shown for this surface and if, under natural conditions, it is exposed to insolation by inversion of the leaf, the insects migrate to the other surface. Since the thrips were shown to be indifferent to bodily posture, the observation suggests that their behaviour is governed primarily by avoidance of exposure to undue heat or dryness and only secondarily by the attractiveness of the stomata-bearing surface.Leaves of cashew tend not to become infested while still immature, and become most heavily infested, if at all, soon after they have hardened. Breeding does not occur on senescent leaves. The positions of feeding thrips are almost random on leaves under abnormal water-stress, but otherwise conform to certain patterns that mainly develop in fixed sequence. On reversal of an undetached leaf and consequent transfer of thrips from one surface to the other, there is no appreciable change in their distribution pattern or the apparent acceptability of the substrate. Changes of pattern were readily induced by injury to the plant during a period of water-stress and less easily, or not at all, when water-stress was low. Injury of areas of the leaf by heat was followed by their colonisation by thrips, and partial severance of branches by increased attack on their leaves.Leaves detached from uninfested trees invariably became acceptable for feeding within four hours. During this period, leaf water-content declined and the ratios of soluble-carbohydrate content and α-amino acids to fresh-leaf weight fell slightly and rose considerably, respectively. In the field, the latter ratio was invariably higher for infested than for uninfested leaf tissue, even on portions of the same leaf. If the nutrient value of leaf tissue is determined by the rate at which α-amino acids are extractable through a stylet puncture, the observed change in acceptability for feeding following plucking may be accounted for by the increase in α-amino-acid concentration. Feeding that is restricted on any one tree to the margins of local leaf injuries during prolonged high water-stress and totally absent when stress is low can be correlated with an α-amino-acid content in the living marginal tissue that is high or low, respectively. The ability of thrips to establish themselves and breed on leaves of a particular tree in the dry season and their failure to do so on leaves of the same tree in the wet season conforms with the greater or less amino-acid concentration occurring in the leaf at these respective times.

Enrichment of amino acids from its aqueous solution by ultrasonic atomization and ultrafine bubbles

2021 ◽  
Author(s):  
Keiji Yasuda ◽  
Koji Hamada ◽  
Yoshiyuki Asakura
Keyword(s):  
Aqueous Solution ◽  
Amino Acids ◽  
Amino Acid ◽  
Enrichment Factor ◽  
Acid Concentration ◽  
Flow Rate ◽  
Amino Acid Concentration ◽  
Solution Ph ◽  
Ultrasonic Atomization ◽  
Enrichment Characteristics

Abstract The enrichment characteristics of amino acids by ultrasonic atomization were investigated. Samples were aqueous solutions of L-phenylalanine and L-tyrosine. The ratio of amino acid concentration in the mist to that in the solution was defined as the enrichment factor. As the flow rate of carrier gas became higher, the collection mass of mist increased and the enrichment factor decreased. The enrichment factor depended on the solution pH. The enrichment factor increased with decreasing amino acid concentration in the solution and enhanced by the addition of ultrafine bubbles.

scholarly journals Free Amino Acid Profiles of Macedonian White Brined Cheese

2021 ◽  
Vol 33 (12) ◽  
pp. 2989-2992
Author(s):  
Borche Makarijoski ◽  
Gordana Dimitrovska ◽  
Vesna K. Hristova ◽  
Elena Joshevska ◽  
Mahmoud A. Abdelaziz Mahmoud ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acid ◽  
Acid Concentration ◽  
Free Amino Acids ◽  
Free Amino ◽  
Amino Acid Profile ◽  
Amino Acid Concentration ◽  
Amino Acid Profiles ◽  
Parameter Values

The present work is focussed to determine the Macedonian white brined cheese’s free amino acid profile. Four variants of the Macedonian white brined cheese to analyze and determine free amino acid concentration; cheese samples define the Macedonian white brined cheese as a typical cheese. All free amino acids were specified, except the amino acid tyrosine. The detected amino acids in the tested cheese variants were present in different but approximate parameter values. The estimated essential free amino acids, the concentration of lysine was found highest in all examined samples with values from 26.40 ± 0.02 mg% to 28.20 ± 0.04 mg% and the concentration of threonine was the lowest from 3.19 ± 0.02 mg% to 3.32 ± 0.02 mg%). In the detected unessential free amino acids, the concentration of aspartic amino acid was highest in all the samples with values from 11.02 ± 0.05 mg% to 11.32 ± 0.03 mg% and the concentration of proline was at the lowest level from 4.16 ± 0.06 mg% to 4.22 ± 0.04 mg%.

scholarly journals Regulatory volume decrease in cultured kidney cells (A6): role of amino acids.

1995 ◽  
Vol 106 (3) ◽  
pp. 525-542 ◽  
Author(s):  
P De Smet ◽  
J Simaels ◽  
P E Declercq ◽  
W Van Driessche
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Acid Concentration ◽  
Short Circuit ◽  
Regulatory Volume Decrease ◽  
Short Circuit Current ◽  
Amino Acid Concentration ◽  
Cell Content ◽  
Volume Decrease

Volume regulation was studied in A6 epithelia grown on permeable supports by measuring cell thickness (Tc) while simultaneously recording short circuit current (ISC) and transepithelial conductance (Gt). Lowering the tonicity of the basolateral solution (pi b) from 250 or 215 to 140 mOsm/kg elicited a rapid rise in Tc followed by a regulation of the cell volume towards control. This decrease in Tc displays the characteristics of the regulatory volume decrease (RVD). Upon restoring the isoosmotic conditions, Tc decreased rapidly below its control value. A post RVD regulatory volume increase (RVI) as described for other cell types was not observed. The subsequent reduction of the basolateral osmolality increased Tc to the level recorded at the end of the first hypoosmotic pulse. Because cell content was not altered during the isoosmotic period the second hypoosmotic challenge was isotonic with the cell and did therefore not evoke an RVD. However, the cell did not lose its ability to volume regulate since an RVD could be elicited by further reduction of pi b from 140 to 100 mOsm/kg. The possibility of an involvement of amino acids in the RVD was tested. The amount of amino acids in the cell as well as excreted in the bath was determined by amino acid analysis. Millimolar concentrations of threonine, serine, alanine, glutamate, glycine and aspartate were found in the cell extract. The cellular amino acid concentration was 28.8 +/- 0.4 mM. The amounts of glycine, aspartate and glutamate excreted from the cell during the hypotonic treatment were significantly larger than in control conditions. The excretion of these amino acids during hypotonicity decreased the cellular amino acid concentration by 8.4 +/- 0.2 mM. This quantity cannot completely account for the RVD during the first hypotonic challenge. The addition of glycine, aspartate and glutamate to the bathing solutions, although used at concentrations higher than intracellularly, did not reduce RVD. On the contrary, this maneuver increased the amplitude of the RVD following both hypoosmotic pulses. This result suggests a stimulatory role of the amino acids on the processes responsible for the RVD.

scholarly journals Amino acid composition of the milk of some mammalian species changes with stage of lactation

1994 ◽  
Vol 72 (6) ◽  
pp. 845-853 ◽  
Author(s):  
Teresa A. Davis ◽  
Hanh V. Nguyen ◽  
Roselina Garcia-Bravo ◽  
Marta L. Fiorotto ◽  
Evelyn M. Jackson ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Concentration ◽  
Mammalian Species ◽  
Amino Acid Pattern ◽  
Amino Acid Concentration ◽  
Total Amino Acid ◽  
Papio Cynocephalus ◽  
Mature Milk

To determine whether the amino acid composition of milk changes during lactation, we compared the amino acid pattern (concentration of each individual amino acid relative to the total amino acid concentration) of colostrum with that of mature milk in six mammalian species. In the human, horse, pig and cow, the pattern of amino acids changed between colostrum and mature milk: glutamate, proline, methionine, isoleucine and lysine increased; cystine, glycine, serine, threonine and alanine decreased. In these four species, the total amino acid concentration also decreased 75% between colostrum and mature milk. In the baboon (Papio cynocephalus anubis and Papio cynocephalus anubis/Papio cynocephalus cynocephalus) and rhesus monkey (Macaca mulatta), however, there was little change in the pattern of amino acids between colostrum and mature milk, and total amino acid concentration decreased only about 25% between colostrum and mature milk. Mature milk rather than colostrum was the most similar among the three primates in both amino acid pattern and total amino acid concentration. We conclude, in those species in which total amino acid concentrations decline substantially between colostrum and mature milk, amino acid patterns also change. The presence of a change in amino acid pattern and total amino acid concentration during lactation appears to be unrelated to phylogenetic order.

Similarity of olfactory receptor responses (EOG) of freshwater and marine catfish to amino acids

1980 ◽  
Vol 58 (10) ◽  
pp. 1778-1784 ◽  
Author(s):  
John Caprio
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Acid Concentration ◽  
Olfactory Receptor ◽  
Olfactory System ◽  
Olfactory Receptors ◽  
Amino Acid Concentration ◽  
Side Chains ◽  
The North ◽  
Species Specific

A comparison of olfactory receptor responses of three species of freshwater catfishes (family Ictaluridae) and one species of marine catfish (family Arridae) was performed. With the exception of the reduced response of the sea catfish (Arius felis) to L-glutamine, no distinctive species specific differences in the electro-olfactogram (EOG) responses were noted. The phasic EOG response increased exponentially with a logarithmic increase in amino acid concentration from threshold to 10−2M. The relative stimulatory effectiveness of the amino acids tested was similar among the four species. The olfactory receptors were highly responsive to L-cysteine and to amino acids containing five carbon atoms having unbranched and uncharged side chains. From phyletic relationships of the species tested, the present data suggest that the olfactory system of the North American catfishes has remained temporally conservative.

scholarly journals AMINO ACID CONCENTRATION BY A FREE CELL NEOPLASM: RELATIONS AMONG AMINO ACIDS

1952 ◽  
Vol 198 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Halvor N. Christensen ◽  
Thomas R. Riggs ◽  
Herbert. Fischer ◽  
Irene M. Palatine
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Acid Concentration ◽  
Free Cell ◽  
Amino Acid Concentration ◽  
Cell Neoplasm
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