scholarly journals Amino Acids as Gustatory Stimuli in the Rat

1962 ◽  
Vol 45 (4) ◽  
pp. 681-701 ◽  
Author(s):  
Bruce P. Halpern ◽  
Rudy A. Bernard ◽  
Morley R. Kare
Keyword(s):  
Amino Acids ◽  
Neural Activity ◽  
Receptor Site ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
High Concentration ◽  
Low Concentration ◽  
Common Receptor ◽  
Amino Acid Solutions ◽  
Selection Of

Neural activity in intact chorda tympani nerve of rats was studied with an electronic summator. Neural activity increased when amino acid solutions 0.01 M or above passed over the tongue. Response magnitude, at concentrations close to solubility limits for the amino acids tested, was: DL-methionine < DL-tryptophan < DL-valine < DL-alanine < glycine < 0.1 M NaCl. Maximum response magnitudes to 1 M D-, and 1.2 M DL-alanine, and 1.5 M glycine developed in 1 to 3 minutes. Following such stimulation, a 63 per cent reduction in response to 0.1 M NaCl occurred 60 minutes after the first stimulation (medians). The depression was still present 20 hours later. Responses to glycine and alanine were not depressed. Amino acids vs. water preferences were investigated. With ascending concentration sequences, rats selected low concentration DL- and L-alanine and glycine; accepted D-, L-, and DL-tryptophan and low concentration DL-methionine; and rejected high concentration glycine, DL-alanine, and DL-methionine. Descending sequences showed depressed and delayed selection of glycine and DL-alanine, and DL-methionine and D- and L-tryptophan rejection. Both groups rejected DL-valine. It is concluded that glycine and alanine receptor effects differ from those of NaCl, but that all three compounds may affect a common receptor site. Prior exposure to amino acids may modify subsequent neural and/or behavioral responses.

scholarly journals A Few Experimental Suggestions Using Minerals to Obtain Peptides with a High Concentration of L-Amino Acids and Protein Amino Acids

Symmetry ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2046
Author(s):  
Dimas A. M. Zaia ◽  
Cássia Thaïs B. V. Zaia
Keyword(s):  
Amino Acids ◽  
Rna World ◽  
High Concentration ◽  
Protein World ◽  
Protein Amino Acids ◽  
Hydrothermal Environment ◽  
World Hypothesis ◽  
Prebiotic Earth ◽  
Hydrothermal Environments ◽  
Selection Of

The peptides/proteins of all living beings on our planet are mostly made up of 19 L-amino acids and glycine, an achiral amino acid. Arising from endogenous and exogenous sources, the seas of the prebiotic Earth could have contained a huge diversity of biomolecules (including amino acids), and precursors of biomolecules. Thus, how were these amino acids selected from the huge number of available amino acids and other molecules? What were the peptides of prebiotic Earth made up of? How were these peptides synthesized? Minerals have been considered for this task, since they can preconcentrate amino acids from dilute solutions, catalyze their polymerization, and even make the chiral selection of them. However, until now, this problem has only been studied in compartmentalized experiments. There are separate experiments showing that minerals preconcentrate amino acids by adsorption or catalyze their polymerization, or separate L-amino acids from D-amino acids. Based on the [GADV]-protein world hypothesis, as well as the relative abundance of amino acids on prebiotic Earth obtained by Zaia, several experiments are suggested. The main goal of these experiments is to show that using minerals it is possible, at least, to obtain peptides whose composition includes a high quantity of L-amino acids and protein amino acids (PAAs). These experiments should be performed using hydrothermal environments and wet/dry cycles. In addition, for hydrothermal environment experiments, it is very important to use one of the suggested artificial seawaters, and for wet/dry environments, it is important to perform the experiments in distilled water and diluted salt solutions. Finally, from these experiments, we suggest that, without an RNA world or even a pre genetic world, a small peptide set could emerge that better resembles modern proteins.

Large enhancement of canine taste responses to amino acids by salts

1993 ◽  
Vol 264 (6) ◽  
pp. R1071-R1076 ◽  
Author(s):  
T. Ugawa ◽  
K. Kurihara
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Sodium Potassium ◽  
Calcium Salts ◽  
Receptor Sites ◽  
Large Enhancement ◽  
Magnesium Salts ◽  
High Concentrations

The effects of salts on the canine taste responses to amino acids were examined by recording the activity of the chorda tympani nerve. 1) The tonic responses to most amino acids examined were significantly enhanced by the presence of various salts. 2) The degree of the enhancement varied with the species of amino acid and salt. The responses to most amino acids were enhanced by sodium, potassium, and calcium salts, but not enhanced by magnesium salts. The response to methionine, for example, was enhanced by NaCl, but not by Na phosphate of equimolar Na+. 3) The responses to glycine and alanine were suppressed by high concentrations of NaCl. 4) The presence of salts (NaCl and CaCl2) enhanced the responses to amino acids without affecting the thresholds for the amino acids, suggesting that the presence of the salts did not change the affinity of amino acids to the receptor sites. 5) The enhancing effects of salts on the responses to amino acids could not be explained in terms of permeability of cation and anion of salts. It was speculated that the binding of cation and anion of salts on the receptor membranes induces exposure of the receptor sites for amino acids available for binding of amino acids.

scholarly journals Gustatory Responses to Amino Acids in the Chorda Tympani Nerve of C3H Mice

1998 ◽  
Vol 23 (6) ◽  
pp. 699-707 ◽  
Author(s):  
S. Harada ◽  
K. Yamaguchi ◽  
Y. Kasahara
Keyword(s):  
Amino Acids ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
C3h Mice

Comparative Analysis of Free Amino Acids in Parapenaeopsis hardwickii, Penaeus vannamei and Macrobrachium nipponensis

2013 ◽  
Vol 781-784 ◽  
pp. 1528-1533
Author(s):  
Yi Hua Zhang ◽  
Shun Sheng Chen ◽  
Wei Qiang Qiu ◽  
Shou Kun Cheng
Keyword(s):  
Amino Acids ◽  
Comparative Analysis ◽  
Amino Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Penaeus Vannamei ◽  
High Concentration ◽  
Automatic Amino Acid Analyzer ◽  
Low Concentration ◽  
Amino Acid Analyzer

The contents of free amino acids(FAAs) in Parapenaeopsis hardwickii, Penaeus vannamei and Macrobrachium nipponensis was analyzed by using the automatic amino acid analyzer in this study. The results show that the sequence from the highest to the lowest in total amount of FAAs is Parapenaeopsis hardwickii, Penaeus vannamei and Macrobrachium nipponensis. SPSS(19.0) results indicate that except for Cys, Lys and Thr, FAAs in these three shrimps are significant different (p<0.05), and all of them have a high concentration of Arg, Gly and Pro and a low concentration of Asp and Cys. The content of Gly in shrimp is higher than that of crab and oyster. Both Arg and Gly significantly contribute to the taste of the three shrimps, Glu and Pro play an important role in the flavor of Parapenaeopsis hardwickii and Penaeus vannamei, while not as significant as in the taste of Macrobrachium nipponensis. Composition modes of FAAs which make major contributions to flavor in marine shrimps, Parapenaeopsis hardwickii and Penaeus vannamei, are similar, but different from freshwater shrimp, Macrobrachium nipponensis.

Study on Switch from High-concentration to Low-concentration Tacalcitol during Concomitant Use of Bath-PUVA Therapy

2007 ◽  
Vol 69 (6) ◽  
pp. 660-664
Author(s):  
Maki IWAKIRI ◽  
Noriko YASAKA ◽  
Kotaro ITO ◽  
Yuichi YOSHIDA ◽  
Yumiko KUBOTA ◽  
...  
Keyword(s):  
Puva Therapy ◽  
High Concentration ◽  
Low Concentration

ASSESSMENT OF HEAVY METAL CONCENTRATION IN COCONUT WATER

1970 ◽  
pp. 07-10
Author(s):  
MdDidarul Islam, Ashiqur Rahaman, Aboni Afrose
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Heavy Metal Concentration ◽  
Coconut Water ◽  
Toxic Heavy Metals ◽  
High Concentration ◽  
Toxic Heavy Metal ◽  
Low Concentration ◽  
Wet Ashing ◽  
Aas Method

This study was based on determining concentration of essential and toxic heavy metal in coconut water available at a local Hazaribagh area in Dhaka, Bangladesh. All essential minerals, if present in the drinking water at high concentration or very low concentration, it has negative actions. In this study, fifteen samples and eight heavy metals were analyzed by Atomic Absorption Spectroscopy (AAS) method which was followed by wet ashing digestion method. The concentration obtained in mg/l were in the range of 0.3 to 1.5, 7.77 to 21.2, 0 to 0.71, 0 to 0.9, 0 to 0.2, 0.9 to 17.3, 0.1 to 0.9, 0 to 0.9 and 0 to 0.7 for Fe, Ni, Cu, Cd, Cr, Zn, Pb and Se respectively. From this data it was concluded that any toxic heavy metals like Cd, Cr, Pb and Ni exceed their toxicity level and some essential nutrients were in low concentration in those samples. 

Assessment of micro and macro nutrients in poultry feeds available in Dhaka city, Bangladesh.

2017 ◽  
Vol 1 ◽  
pp. 264
Author(s):  
Md Didarul Islam ◽  
Ashiqur Rahaman ◽  
Fahmida Jannat
Keyword(s):  
Heavy Metals ◽  
Adverse Effect ◽  
The Other ◽  
Nutrient Level ◽  
Dhaka City ◽  
Toxic Heavy Metals ◽  
High Concentration ◽  
Low Concentration ◽  
Feed Formulation ◽  
Macro Nutrients

This study was based on to determine the concentration of macro and micro nutrients as well as toxic and nontoxic heavy metals present in the chicken feed available in Dhaka city of Bangladesh. All macro nutrients, if present in the feed at high concentration have some adverse effect, at the same time if this nutrient present in the feed at low concentration this have some adverse effect too. So that this nutrient level should be maintained at a marginal level. On the other side toxic heavy metals if present in the feed at very low concentration those can contaminate the total environment of the ecosystem. In this study six brand samples (starter, grower, finisher and layer) which was collected from different renowned chicken feed formulation industry in Bangladesh. Those samples were prepared for analysis by wet ashing and then metals were determined by Atomic Absorption Spectroscopy. It was found that 27.7 to 68.4, 57.3 to 121.9, 0.21 to 4.1, 0.32 to 2.1, 0.11 to 1.58, 0.28 to 2.11 and 0.28 to 1.78 for zinc, iron, copper, mercury, cadmium, nickel and cobalt respectively. It was found that essential macro and micro nutrients were present in the feed in low concentration on the other side mercury was present in high concentration in the feed samples.

The Effects of Shock Vancomycin Concentrations on the Formation of Heteroresistance in Staphylococcus aureus

2020 ◽  
Vol 65 (9-10) ◽  
pp. 3-7
Author(s):  
V. V. Gostev ◽  
Yu. V. Sopova ◽  
O. S. Kalinogorskaya ◽  
M. E. Velizhanina ◽  
I. V. Lazareva ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
In Vitro Selection ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
High Concentration ◽  
Short Term ◽  
High Concentrations ◽  
Selection Of ◽  
Selection Of Resistance ◽  
Test Cultures

Glycopeptides are the basis of the treatment of infections caused by MRSA (Methicillin-Resistant Staphylococcus aureus). Previously, it was demonstrated that antibiotic tolerant phenotypes are formed during selection of resistance under the influence of high concentrations of antibiotics. The present study uses a similar in vitro selection model with vancomycin. Clinical isolates of MRSA belonging to genetic lines ST8 and ST239, as well as the MSSA (ATCC29213) strain, were included in the experiment. Test isolates were incubated for five hours in a medium with a high concentration of vancomycin (50 μg/ml). Test cultures were grown on the medium without antibiotic for 18 hours after each exposure. A total of ten exposure cycles were performed. Vancomycin was characterized by bacteriostatic action; the proportion of surviving cells after exposure was 70–100%. After selection, there was a slight increase in the MIC to vancomycin (MIC 2 μg/ml), teicoplanin (MIC 1.5–3 μg/ml) and daptomycin (MIC 0.25–2 μg/ml). According to the results of PAP analysis, all strains showed an increase in the area under curve depending on the concentration of vancomycin after selection, while a heteroresistant phenotype (with PAP/AUC 0.9) was detected in three isolates. All isolates showed walK mutations (T188S, D235N, E261V, V380I, and G223D). Exposure to short-term shock concentrations of vancomycin promotes the formation of heteroresistance in both MRSA and MSSA. Formation of VISA phenotypes is possible during therapy with vancomycin.

Chemical Composition and Metal Speciation in Porewaters from the Upper Qu’Appelle River Basin, Saskatchewan

1993 ◽  
Vol 28 (1) ◽  
pp. 83-110 ◽  
Author(s):  
Richard E. Farrell ◽  
Jae E. Yang ◽  
P. Ming Huang ◽  
Wen K. Liaw
Keyword(s):  
Amino Acids ◽  
Trace Metal ◽  
River Basin ◽  
Drainage Basin ◽  
Metal Speciation ◽  
Anthropogenic Activities ◽  
High Concentration ◽  
Metal Concentrations ◽  
Carbonate Equilibria ◽  
The Impact

Abstract Porewater samples from the upper Qu’Appelle River basin in Saskatchewan, Canada, were analyzed to obtain metal, inorganic ligand and amino add profiles. These data were used to compute the aqueous speciation of the metals in each porewater using the computer program GEOCHEM-PC. The porewaters were classified as slightly to moderately saline. Metal concentrations reflected both the geology of the drainage basin and the impact of anthropogenic activities. Whereas K and Na were present almost entirely as the free aquo ions, carbonate equilibria dominated the speciation of Ca. Mg and Mn (the predominant metal ligand species were of the type MCO3 (s). MCO30. and MHCO3+). Trace metal concentrations were generally within the ranges reported for non-polluted freshwater systems. Whereas the speciation of the trace metals Cr(III) and Co(II) was dominated by carbonate equilibria, Hg(II)-, Zn(II)- and Fe(II)-speciation was dominated by hydroxy-metal complexes of the type M(OH)+ and M(OH)2°. The speciation of Fe(III) was dominated by Fe(OH)3 (s). In porewaters with high chloride concentrations (&gt; 2 mM), however, significant amounts of Hg(II) were bound as HgCl20 and HgClOH0. The aqueous speciation of Al was dominated by Al(OH)4− and Al2Si2O4(OH)6 (s). Total concentrations of dissolved free amino acids varied from 15.21 to 25.17 umole L−1. The most important metal scavenging amino acids were histidine (due to high stability constants for the metal-histidine complexes) and tryptophan (due to its relatively high concentration in the porewaters. i.e., 5.96 to 7.73 umole L−1). Secondary concentrations of various trace metal-amino add complexes were computed for all the porewaters, but metal-amino acid complexes dominated the speciation of Cu(II) in all the porewaters and Ni(II) in two of the porewaters.

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