Responses of single facial taste fibers in the channel catfish, Ictalurus punctatus, to amino acids

1992 ◽  
Vol 68 (4) ◽  
pp. 1012-1026 ◽  
Author(s):  
J. Kohbara ◽  
W. Michel ◽  
J. Caprio
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Spontaneous Activity ◽  
Ictalurus Punctatus ◽  
Channel Catfish ◽  
Response Times ◽  
Hierarchical Cluster ◽  
Whitney Test ◽  
Mann Whitney Test ◽  
Significant Difference

1. Amino acids and nucleotides stimulate taste receptors of teleosts. In this report, responses to these compounds of 105 facial taste fibers (79 fully characterized) that innervate maxillary barbel taste buds of the channel catfish (Ictalurus punctatus) were analyzed. 2. The fully characterized facial taste fibers that responded to amino acids (n = 68) were generally poorly responsive to nucleotides and related substances (NRS), whereas the fibers responsive to NRS (n = 11) were poorly responsive to amino acids. Spike discharge of the amino acid-responsive fibers to the most potent amino acid stimulus tested per fiber increased 44-fold from a mean spontaneous activity of 2.1 +/- 3.5 to 92.1 +/- 42.4 (SD) spikes/3 s. Spike activity of the NRS-responsive fibers to NRS increased 11.5-fold from a mean spontaneous activity of 3.4 +/- 5.9 to 39.1 +/- 27.4 spikes/3 s. There was no significant difference between the spontaneous rates, but stimulus evoked spike rates for the amino acid-responsive fibers were significantly greater (P < 0.05; Mann-Whitney test) than those for the NRS-responsive fibers. 3. Hierarchical cluster analysis based on the 3-s response time identified three major groups of neurons. The identified clusters comprised neurons that were highly responsive to either L-alanine (i.e., Ala cluster; n = 39), L-arginine (i.e., Arg cluster; n = 29), or NRS (NRS cluster; n = 11). Fibers comprising the Arg cluster were more narrowly tuned than those within the Ala cluster. This report further characterizes the responses to amino acids of the individual facial taste fibers comprising the Ala and Arg clusters. 4. Subclusters were evident within both of the amino acid-responsive clusters. The Arg cluster was divisible into two subclusters dependent on the response to 1 mM L-proline. Twelve neurons that were significantly (P < 0.05; Mann-Whitney test) more responsive to L-proline than the remaining 17 neurons within the Arg cluster formed the Arg/Pro subcluster; these latter 17 neurons comprised the Arg subcluster. However, there was no significant difference (Mann-Whitney test) in the response to L-arginine between fibers within either subcluster across four different response times analyzed. Fibers within the Ala cluster were generally poorly responsive to L-proline. Four alanine subclusters were suggested on the basis of their relative responses to L-alanine, D-alanine, L-arginine, and the NRS; however, of the 39 fibers comprising the alanine cluster, two alanine subclusters comprised only two fibers each, and the third subcluster consisted of four fibers.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Homochirality May Not Be a Prerequisite for Protein Structure and Function: A Computational Model Investigation of Prebiotic Peptides

2020 ◽  
Author(s):  
Jianxun Shen ◽  
Pauline M. Schwartz ◽  
Carl Barratt
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Hierarchical Cluster ◽  
Building Blocks ◽  
Beta Sheets ◽  
Folding Energy ◽  
Primitive Earth ◽  
C Terminus ◽  
Significant Difference ◽  
Prebiotic Amino Acids

On the primitive Earth, both L- and D-amino acids would have been present. However, only L-amino acids are essential blocks to construct proteins in modern life. To study the relative stability of homochiral and heterochiral peptides, a variety of computational methods were employed. 10 prebiotic amino acids (Gly, Ala, Asp, Glu, Ile, Leu, Pro, Ser, Thr, and Val) were previously determined by multiple previous meteorite, spark discharge, and hydrothermal vent studies. We focused on what had been reported as primary early Earth polypeptide analogs: 1ARK, 1PPT, 1ZFI, and 2LZE. Tripeptide composed of only Asp, Ser, and Val exemplified that different positions (i.e., N-terminus, C-terminus, and middle) made a difference in minimal folding energy of peptides, while the classification of amino acid (hydrophobic, acidic, or hydroxylic) did not show significant difference. Hierarchical cluster analysis for dipeptides with all possible combinations of the proposed 10 prebiotic amino acids and their D-amino acid substituted derivatives generated five clusters. Prebiotic polypeptides were built up to test the significance of molecular fluctuations, secondary structure occupancies, and folding energy differences based on these clusters. Most interestingly, among 129 residues, mutation sensitivity profiles presented that the ratio of more stable to less stable to equally stable D-amino acids was about 1:1:1. In conclusion, some combinations of a mixture of L- and D-amino acids can act as essential building blocks of life. Peptides with &alpha;-helices, long &beta;-sheets, and long loops are usually less sensitive to D-amino acid replacements in comparison to short &beta;-sheets.

scholarly journals Odorant receptors activated by amino acids in sensory neurons of the channel catfish Ictalurus punctatus.

1993 ◽  
Vol 102 (6) ◽  
pp. 1085-1105 ◽  
Author(s):  
T T Ivanova ◽  
J Caprio
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Ictalurus Punctatus ◽  
Channel Catfish ◽  
Olfactory Receptor ◽  
Action Potentials ◽  
Single Channel ◽  
Odorant Receptors ◽  
Olfactory Neurons ◽  
Whole Cell

Odorant receptors activated by amino acids were investigated with patch-clamp techniques in olfactory receptor neurons of the channel catfish, Ictalurus punctatus. The L-isomers of alanine, norvaline, arginine, and glutamate, known to act predominantly on different olfactory receptor sites, activated nondesensitizing inward currents with amplitudes of -2.5 to -280 pA in olfactory neurons voltage-clamped at membrane potentials of -72 or -82 mV. Different amino acids were shown to induce responses in the same sensory neurons; however, the amplitude and the kinetics of the observed whole cell currents differed among the stimuli and may therefore reflect activation of different amino acid receptor types or combinations of receptor types in these cells. Amino acid-induced currents appeared to have diverse voltage dependence and could also be classified according to the amplitude of the spontaneous channel fluctuations underlying the macroscopic currents. A mean single-channel conductance (gamma) of 360 fS was estimated from small noise whole-cell currents evoked by arginine within the same olfactory neuron in which a mean gamma value of 23.6 pS was estimated from 'large noise' response to norvaline. Quiescent olfactory neurons fired bursts of action potentials in response to either amino acid stimulation or application of 8-Br-cyclic GMP (100 microM), and voltage-gated channels underlying generation of action potentials were similar in these neurons. However, in whole-cell voltage-clamp, 8-Br-cyclic GMP evoked large rectangular current pulses, and single-channel conductances of 275, 220, and 110 pS were obtained from the discrete current levels. These results suggest that in addition to the cyclic nucleotide-gated transduction channels, olfactory neurons of the channel catfish possess a variety of odor receptors coupled to different types of transduction channels.

scholarly journals Electro-olfactogram and multiunit olfactory receptor responses to complex mixtures of amino acids in the channel catfish, Ictalurus punctatus.

1991 ◽  
Vol 98 (4) ◽  
pp. 699-721 ◽  
Author(s):  
J S Kang ◽  
J Caprio
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Binary Mixtures ◽  
Ictalurus Punctatus ◽  
Channel Catfish ◽  
Olfactory Receptor ◽  
Complex Mixtures ◽  
Neutral Amino Acids ◽  
Acidic Amino Acids ◽  
Receptor Sites

In vivo electrophysiological recordings from populations of olfactory receptor neurons in the channel catfish, Ictalurus punctatus, clearly showed that both electro-olfactogram and integrated neural responses of olfactory receptor cells to complex mixtures consisting of up to 10 different amino acids were predictable with knowledge of (a) the responses to the individual components in the mixture and (b) the relative independence of the respective receptor sites for the component stimuli. All amino acid stimuli used to form the various mixtures were initially adjusted in concentration to provide approximately equal response magnitudes. Olfactory receptor responses to both multimixtures and binary mixtures were recorded. Multimixtures were formed by mixing equal aliquots of 3-10 different amino acids. Binary mixtures were formed by mixing equal aliquots of two equally stimulatory solutions. Solution 1 contained either one to nine different neutral amino acids with long side-chains (LCNs) or one to five different neutral amino acids with short side-chains (SCNs). Solution 2, comprising the binary mixture, consisted of only a single stimulus, either a LCN, SCN, basic, or acidic amino acid. The increasing magnitude of the olfactory receptor responses to mixtures consisting of an increasing number of neutral amino acids indicated that multiple receptor site types with highly overlapping specificities exist to these compounds. For both binary mixtures and multimixtures composed of neutral and basic or neutral and acidic amino acids, the receptor responses were significantly enhanced compared with those mixtures consisting of an equal number of only neutral amino acids. These results demonstrate that receptor sites for the basic and acidic amino acids, respectively, are highly independent of those for the neutral amino acids, and suggest that a mechanism for synergism is the simultaneous activation of relatively independent receptor sites by the components in the mixture. In contrast, there was no evidence for the occurrence of mixture suppression.

Rapid kinetic measurements of second messenger formation in olfactory cilia from channel catfish

1993 ◽  
Vol 264 (4) ◽  
pp. C906-C911 ◽  
Author(s):  
D. Restrepo ◽  
I. Boekhoff ◽  
H. Breer
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Ictalurus Punctatus ◽  
Channel Catfish ◽  
Time Scale ◽  
High Concentration ◽  
Kinetic Measurements ◽  
Olfactory Cilia ◽  
Cyclic Monophosphate ◽  
Transient Elevation

The effect of stimulating olfactory cilia from the channel catfish (Ictalurus punctatus) with odorant amino acids on the formation of adenosine 3',5'-cyclic monophosphate, guanosine 3',5'-cyclic monophosphate, and inositol 1,4,5-trisphosphate (IP3) was studied in the subsecond time scale using a quenched flow technique. L-Alanine (L-Ala) and L-cysteine (L-Cys) (100 microM) elicited a transient elevation in IP3 levels that peaked at 25 ms. In contrast, even at high concentration a mixture of odorant amino acids (1 mM L-Ala, L-Cys, L-norleucine, L-glutamate, L-proline, and L-arginine) did not elicit a change in cAMP levels in this time scale and caused only relatively slow and minor increases in cGMP. The dose-response relationship for the IP3 response of L-Cys and L-Ala in the range from 10 nM to 1 mM is consistent with previous electrophysiological and ligand binding experiments. Odorant amino acid-stimulated IP3 formation was GTP dependent and was inhibited by guanosine 5'-O-(2-thiodiphosphate), suggesting that the response was G protein mediated. These results are consistent with a mediatory role for IP3 in amino acid olfactory signal transduction in catfish.

Electrophysiological responses of single olfactory bulb neurons to amino acids in the channel catfish, Ictalurus punctatus

1995 ◽  
Vol 74 (4) ◽  
pp. 1421-1434 ◽  
Author(s):  
J. Kang ◽  
J. Caprio
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Olfactory Bulb ◽  
Ictalurus Punctatus ◽  
Channel Catfish ◽  
Action Potentials ◽  
Recording Time ◽  
Over Time ◽  
Olfactory Bulb Neurons

1. Responses of 89 single olfactory bulb neurons from 43 channel catfish, Ictalurus punctatus, to amino acid odorants were recorded in vivo simultaneously with the electro-olfactogram (EOG). Recording time for individual neurons ranged from 16 to 344 min. The averaged spontaneous frequency ranged from x003C; 1 to 16 action potentials/s with a mean frequency of 5.2 +/- 3.6 (SD) action potentials/s. 2. Histological examinations of carbocyanine dye 1,1'diocadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI)-labeled olfactory bulbs and electrical stimulation of the olfactory tracts in a subset of experiments suggested that the majority of the recorded olfactory bulb neurons in this study were mitral cells. 3. Olfactory bulb neurons responded to amino acids with either an excitation or suppression of the background neural activity. Of the 337 stimulus applications, 28% of the responses were excitatory, and 33% were suppressive. The approximately 1:1 ratio of excitatory to suppressive responses for all stimulus applications suggests that suppressive responses also play important roles in the coding of odorant information in the channel catfish. 4. Responses of single olfactory bulb neurons were highly reproducible over time (up to 5 h). Responses to any amino acid never changed from excitation to suppression, or vice versa over time. 5. Single olfactory bulb neurons responded with excitation or suppression to more than one amino acid previously indicated to bind to independent receptors. 6. Estimated threshold concentrations for activation of an olfactory bulb neuron ranged from 10(-7) to 10(-3) M and were different from neuron to neuron for a particular stimulus and from stimulus to stimulus for a particular neuron. Responses of single olfactory bulb neurons to a given amino acid did not change from excitation to suppression, or vice versa, across different suprathreshold concentrations.

scholarly journals Analysis of the drivers and benefits of BIM incorporation into quantity surveying profession

2018 ◽  
Vol 16 (5) ◽  
pp. 750-766 ◽  
Author(s):  
Solomon Olusola Babatunde ◽  
Damilola Ekundayo ◽  
Olubola Babalola ◽  
Jumoke Aduramigba Jimoh
Keyword(s):  
Undergraduate Students ◽  
Practical Implication ◽  
Empirical Studies ◽  
Information Modeling ◽  
Content Type ◽  
Whitney Test ◽  
Mann Whitney Test ◽  
Significant Difference ◽  
Building Information ◽  
Quantity Surveying

Purpose Building information modeling (BIM) inclusion in education pedagogy is crucial in preparing skilled graduates for employment in the construction industry. Against this backdrop, studies on BIM education abound in architecture, engineering and construction (AEC) programmes in higher education institutions (HEIs). However, there are limited empirical studies on BIM potentials in the quantity surveying (QS) profession in HEIs, particularly in developing countries. The purpose of this study is to identify and assess the BIM drivers and benefits as important to the QS profession using an empirical approach. Design/methodology/approach A comprehensive literature review was conducted to identify the BIM drivers and benefits in relation to the QS profession, which was used to design a questionnaire. To capture a broad perception, a questionnaire survey was carried out which targeted the academia and final year undergraduate students from two selected universities offering QS honour degree programmes in Nigeria. Data collected were analysed using mean score, standard deviation and Mann–Whitney test. Findings The study identified 12 BIM drivers in relation to the QS profession and the analysis of the ranking revealed that almost all the identified BIM drivers are considered by respondents as important. The study further identified 14 BIM benefits and the analysis of the ranking indicated that all the identified BIM benefits are considered as important. The results of the Mann–Whitney test indicated a slight statistically significant difference, particularly in one of the selected universities on the ranking of the BIM drivers and benefits as important to the QS profession. Practical implication The findings of the study provide empirical evidence on the current perceptions of the drivers and benefits of BIM to QS academia and students as they explore the concept for the advancement of QS profession. Originality/value This study would provide practical insights to use BIM for QS practice. Also, this study would contribute to improving the QS graduates and professional quantity surveyors understanding of the BIM knowledge applicable to QS profession.

scholarly journals PENGARUH MENYIKAT GIGI DENGAN SIWAK (Salvadora persica) TERHADAP pH SALIVA

2016 ◽  
Vol 4 (1) ◽  
pp. 45-54
Author(s):  
Yossy Juliarni ◽  
Gunawan Gunawan2
Keyword(s):  
T Test ◽  
Control Group ◽  
Case Group ◽  
Salvadora Persica ◽  
Control Group Design ◽  
Whitney Test ◽  
Mann Whitney Test ◽  
Significant Difference ◽  
Salivary Ph ◽  
Paired T Test

Background: Salivary pH is one of factor which involved in caries development. Decreasing of salivary pH will cause enamel demineralization. Miswak (Salvadora persica) as a toothbrush because it has mechanical and chemical effects such as essential oil and bicarbonate which can stimulate salivary secretion. Thus, it will increase the buffer capacity and salivary pH lead to enamel remineralization. Objective: This study aimed to know the effect of toothbrushing with miswak (Salvadora persica) on salivary pH. Methods: The clinical experiment study with pre-test and post-test control group design. The sample of this study is the students of Faculty of Dentistry, Andalas University, Padang. There are 34 students that divided into two groups randomly that is case and control group. Case group used miswak while control group used conventional toothbrush, respectively brushing horizontally for 2 minutes. Salivary pH was measured using digital pH meter in scale of 0.0 to 14.0 with 0.1 sensitivity from pen type pH meter. The data analyzed by Shapiro-Wilk test continued by paired t-test and Mann-Whitney test. Results: paired t-test produced significant value p=0,001 in case group and p=0,000 in control group. Mann-Whitney test produced significant value p=0.317. There was no significant difference in statistic among these groups. Conclusion: Toothbrushing with miswak has effect on salivary pH. Miswak as effective as toothbrush on salivary pH Keywords:Toothbrushing, miswak (Salvadora persica), Salivar

scholarly journals Evaluation of hydrogel use in the development of Rapanea ferruginea with water restriction by vibrational Fourier Transform Infrared Spectroscopy (FTIR-UATR)

2021 ◽  
Vol 16 (5) ◽  
pp. 1-16
Author(s):  
Douglas Cubas Pereira ◽  
Breno Pupin ◽  
Kumiko Koibuchi Sakane
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fourier Transform Infrared Spectroscopy ◽  
Fourier Transform Infrared ◽  
Control Group ◽  
Water Restriction ◽  
Whitney Test ◽  
Mann Whitney Test ◽  
Water Band ◽  
Significant Difference

This study evaluated the use of hydrogel on the development of Rapanea ferruginea under water restriction through Vibrational Fourier Transform Infrared Spectroscopy (FTIR-UATR). Seedlings of approximately 30 cm height were transferred in pots with 3 L of soil. The group of seedlings was separated into 5 different triplicate treatments according to the amount of hydrogel, as follows: H1 (25%), H2 (20%), H3 (15%), H4 (10%) and S (control without hydrogel). The applied hydrogel was mixed homogeneously with the soil. All treatments were irrigated with 40 mL of water. FTIR spectra were obtained from fresh leaves collected during 13 months of monitoring. The correlation of the hydroxyl (water) band with the main biomolecules between treatments with the control was evaluated using the Mann-Whitney test (p<0.05). The biomolecule bands were subjected to principal component analysis (PCA) and hierarchical clustering analysis (HCA). The results indicate a significant correlation of the water band with the lipid, hemicellulose, cell wall and starch components in the species. The use of hydrogel resulted in a significant difference in the water absorption band in relation to the control group through the Mann-Whitney test and in biomolecules as the HCA and PCA analysis suggested. The best development was observed in groups H4 (10%), H2 (20%) and H3 (15%). The use of hydrogel positively influences the biomolecular development of the Rapanea ferruginea and monitoring is viable by FTIR. Keywords: FTIR infrared spectroscopy, plant water management, superabsorbent polymer.

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