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Letteratura scientifica selezionata sul tema "Amino acids sensing"

Autore: Grafiati

Pubblicato: 26 ottobre 2024

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Articoli di riviste sul tema "Amino acids sensing"

Tang, Lei. "Sensing proteinogenic amino acids". Nature Methods 17, n. 2 (febbraio 2020): 126. http://dx.doi.org/10.1038/s41592-020-0741-z.

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Poulsen, P., B. Wu, R. F. Gaber, Kim Ottow, H. A. Andersen e M. C. Kielland-Brandt. "Amino acid sensing by Ssy1". Biochemical Society Transactions 33, n. 1 (1 febbraio 2005): 261–64. http://dx.doi.org/10.1042/bst0330261.

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Saccharomyces cerevisiae senses extracellular amino acids using two members of the family of amino acid transporters, Gap1 or Ssy1; aspects of the latter are reviewed here. Despite resemblance with bona fide transporters, Ssy1 appears unable to facilitate transport. Exposure of yeast to amino acids results in Ssy1-dependent transcriptional induction of several genes, in particular some encoding amino acid transporters. Amino acids differ strongly in their potency, leucine being the most potent one known. Using a selection system in which potassium uptake was made dependent on amino acid signalling, our laboratory has obtained and described gain-of-function mutations in SSY1. Some alleles conferred inducer-independent signalling; others increased apparent affinity for inducers. These results revealed that amino acid transport is not required for signalling and support the notion that sensing by Ssy1 occurs via its direct interaction with extracellular amino acids. Current work includes development of quantitative assays of sensing. We use the finding by Per Ljungdahl's laboratory that the signal transduction from Ssy1 involves proteolytic removal of an inhibitory part of the transcriptional activator Stp1. Protein-A Z-domain fused to the C-terminus of Stp1 and Western analysis using antibody against horseradish peroxidase allow quantification of sensing.

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Ray, L. B. "Sensing amino acids at the lysosome". Science 347, n. 6218 (8 gennaio 2015): 141–43. http://dx.doi.org/10.1126/science.347.6218.141-p.

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Ray, L. Bryan. "Sensing Amino Acids at the Lysosome". Science Signaling 8, n. 359 (13 gennaio 2015): ec12-ec12. http://dx.doi.org/10.1126/scisignal.aaa6512.

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Zhou, Yanxiu, Bin Yu e Kalle Levon. "Potentiometric Sensing of Chiral Amino Acids". Chemistry of Materials 15, n. 14 (luglio 2003): 2774–79. http://dx.doi.org/10.1021/cm030060e.

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Conigrave, A. D., H. C. Mun e S. C. Brennan. "Physiological significance of L-amino acid sensing by extracellular Ca2+-sensing receptors". Biochemical Society Transactions 35, n. 5 (25 ottobre 2007): 1195–98. http://dx.doi.org/10.1042/bst0351195.

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The calcium-sensing receptor is a multimodal, multimetabolic sensor that mediates the feedback-dependent control of whole body calcium metabolism. Remarkably, in addition to its role in Ca2+o (extracellular Ca2+) sensing, the CaR (Ca2+-sensing receptor) also responds to L-amino acids. L-amino acids appear to activate, predominantly, a signalling pathway coupled with intracellular Ca2+ mobilization, require a threshold concentration of Ca2+o for efficacy and sensitize the receptor to activation by Ca2+o. Here, we review the evidence that the CaR, like other closely related members of the class 3 GPCR (G-protein-coupled receptor) family including GPRC6A, is a broad-spectrum amino acid-sensing receptor, consider the nature of the signalling response to amino acids and discuss its physiological significance.

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Lynch, Ciarán C., Zeus A. De los Santos e Christian Wolf. "Chiroptical sensing of unprotected amino acids, hydroxy acids, amino alcohols, amines and carboxylic acids with metal salts". Chemical Communications 55, n. 44 (2019): 6297–300. http://dx.doi.org/10.1039/c9cc02525a.

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Optical chirality sensing of unprotected amino acids, hydroxy acids, amino alcohols, amines and carboxylic acids based on a practical mix-and-measure protocol with readily available copper, iron, palladium, manganese, cerium or rhodium salts is demonstrated.

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Lushchak, Oleh. "Amino Acids: Sensing and Implication into Aging". Journal of Vasyl Stefanyk Precarpathian National University 2, n. 1 (30 aprile 2015): 51–60. http://dx.doi.org/10.15330/jpnu.2.1.51-60.

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An ability to sense and respond to nutrient availability is an important requisite for life.Nutrient limitation is among main factors to influence the evolution of most cellular processes.Different pathways that sense intracellular and extracellular levels of carbohydtrates, amino acids,lipids, and intermediate metabolites are integrated and coordinated at the organismal levelthrough neuronal and humoral signals. During food abundance, nutrient-sensing pathwaysengage anabolism and storage, whereas limitation triggers the mechanisms, such as themobilization of internal stores including through autophagy. These processes are affected duringaging and are themselves important regulators of longevity, stress resistance, and age-relatedcomplications

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YAO, SHANG J., WEIJIAN XU, TERRI-LYNN DAY, JOHN F. PATZER e SIDNEY K. WOLFSON. "Interference of Glucose Sensing by Amino Acids". ASAIO Journal 40, n. 1 (gennaio 1994): 33–40. http://dx.doi.org/10.1097/00002480-199401000-00007.

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YAO, SHANG J., WEIJIAN XU, TERRI-LYNN DAY, JOHN F. PATZER e SIDNEY K. WOLFSON. "Interference of Glucose Sensing by Amino Acids". Asaio journal 40, SUPPLEMENT 1 (gennaio 1994): 33???40. http://dx.doi.org/10.1097/00002480-199401001-00007.

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Più fonti

Tesi sul tema "Amino acids sensing"

Nakato, Junya. "Physiological studies on gastrointestinal sensing of peptides and amino acids". Kyoto University, 2018. http://hdl.handle.net/2433/232349.

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Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第21148号
農博第2274号
新制||農||1058(附属図書館)
学位論文||H30||N5122(農学部図書室)
京都大学大学院農学研究科食品生物科学専攻
(主査)教授金本龍平, 教授保川清, 教授谷史人
学位規則第4条第1項該当

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Chiang, Mengying. "A Study on the Regulation of Amino Acids and Glucose Sensing Pathways in Saccharomyces cerevisiae". ScholarWorks@UNO, 2013. http://scholarworks.uno.edu/td/1713.

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Nutrient availability regulates eukaryotic cell growth. This study focuses on two signaling pathways, involved in sensing amino acids and carbon sources, which allow cells to respond appropriately to their presence. The first part of this study shows that Ssy1, a plasma membrane localized sensor in the Ssy1-Ptr3-Ssy5 (SPS) amino acid sensing pathway, can detect 19 common L-amino acids with different potencies and affinities based on the physiochemical structure of amino acids. Substituents around alpha carbon are critical for amino acid sensing by Ssy1. Furthermore, a high concentration of cysteine is toxic to cells. Inactivation of SPS signaling confers resistance to cysteine. The second part focuses on the regulation of Hap4, the regulatory subunit of the Hap2/3/4/5 transcriptional factor complex. Many components of the 25-subunit Mediator complex negatively regulate HAP4 expression. Srb8 undergoes post-translational modification in response to changes of the carbon source. Gal11 and Med3 positively regulate HAP4 expression.

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Price, Michelle B. "Functional Analysis of Plant Glutamate Receptors". Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/51946.

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The plant glutamate receptors (GLRs) are homologs of mammalian ionotropic glutamate receptors (iGluRs) and are hypothesized to be potential amino acid sensors in plants. Since their first discovery in 1998, the members of plant GLRs have been implicated in diverse processes such as C/N ratio sensing, root formation, pollen germination and plant-pathogen interaction. However, the exact properties of these channels, such as the spectrum of ligands, ion specificities, and subunit compositions are still not well understood. It is well established that animal iGluRs form homo- or hetero-tetramers in order to form ligand-gated cation channels. The first aspect of this research was to determine if plant GLRs likewise require different subunits to form functional channels. A modified yeast-2-hybrid system approach was initially taken and applied to 14 of the 20 AtGLRs to identify a number of candidate interactors in yeast. Forster resonance energy transfer (FRET), which measures the transfer of energy between interacting molecules, was performed in mammalian cells to confirm interaction between a few of those candidates. Interestingly, despite an abundance of overlapping co-localization between heteromeric combinations, only homomeric interactions were identified between GLRs 1.1 and 3.4 in HEK293 cells. Further, amino acids have been implicated in signaling between plants and microbes, but the mechanisms for amino acid perception in defense responses are far from being understood. Recently it was demonstrated that calcium responses initiated by bacterial and fungal microbe-associated molecular patterns (MAMPs) were diminished in seedlings treated with known agonists and antagonists of mammalian iGluRs, suggesting potential roles of GLRs in pathogen responses. Analysis of publicly available microarray data shows altered gene expression of a sub-fraction of GLRs in response to pathogen infection and bacterial elicitors. Thus, the second goal of my PhD research was aimed at determining whether GLRs are involved in the interaction between plants and pathogens. Gene expression changes of a number of candidate GLRs as well as pathogen growth was examined in response to the plant pathogen Pseudomonas syringae pv. tomato DC3000. Interestingly, single gene and multi-gene deficient plants responded differently with regards to pathogen susceptibility, likely as a result of functional compensation between GLRs.
Ph. D.

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Hoe, Nancy Palme. "Analysis of Temperature Sensing in Yersinia pestis: A Dissertation". eScholarship@UMMS, 1994. https://escholarship.umassmed.edu/gsbs_diss/98.

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The lcrF gene of Yersinia pestis, the etiological agent of plague, encodes a transcription activator responsible for inducing expression of several virulence-related proteins (Yops) in response to temperature. The mechanism of this thermoregulation was investigated. Using a yopE::lacZ reporter fusion, lcrF-mediated thermal regulation was observed in Y. pestis and Escherichia coli. The lcrF gene was sequenced, the 30.8 kDa. LcrF protein identified and purified, and LcrF-dependent yopE-specific DNA binding activity was detected. A sequence similarity search revealed that LcrF exhibits 98% homology to VirF of Yersinia enterocolitica and significant homology to the carboxy termini of other members of the AraC family of transcription activators. During localization studies, a significant proportion of LcrF was found associated with the membrane fraction in E. coli. However, pulse-chase experiments indicated that this result is an artifact of fractionation. lcrF-mediated thermal induction of the yopE::lacZ reporter fusion remains intact in a Shigella flexneri virR mutant. The virR mutation is known to affect thermal induction of Shigellavirulence genes, which are also controlled by an activator in the AraC family. As a first step toward identifying the temperature-sensitive step in the regulation of yop expression, lcrF::lacZ transcriptional fusions were constructed and analyzed in Y. pestis and E. coli. The activity of the fusions was not affected by the native pCD1 virulence plasmid, an intact lcrF gene, or temperature. Thus, induction of lcrF transcription is not essential for temperature-dependent activation of yopE transcription. To confirm these results, attempts were made to identify both the native lcrF message in Y. pestis, and a lcrF-lacZ hybrid message in Y. pestis and E. coli. These attempts were unsuccessful. Examination of LcrF protein production revealed temperature-dependent expression in Y. pestis. Surprisingly, high-level T7 polymerase-directed transcription of the lcrF gene in Escherichia coli also resulted in temperature-dependent production of the LcrF protein. Pulse-chase experiments showed that the LcrF protein was stable at both 26 and 37°C, suggesting that translation rate or message degradation is thermally controlled. Comparison of the amount of LcrF protein produced per unit of message at 26 and 37°C in E. coli indicated that the efficiency of translation of lcrF message increased with temperature. mRNA secondary structure predictions suggest that the lcrF Shine-Dalgarno sequence is sequestered in a stem-loop. A model in which decreased stability of this stem-loop with increasing temperature leads to increased efficiency of translation initiation of lcrF message is presented.

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Springauf, Andreas [Verfasser]. "Electrophysiological characterization of the acid sensing ion channel shark ASIC1b and identification of amino acids controlling the gating of ASIC1 / Andreas Springauf". Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2011. http://d-nb.info/1018222596/34.

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Pushina, Mariia. "Sensing of Anions, Amines, Diols, and Saccharides by Supramolecular Fluorescent Sensors". Bowling Green State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1558539245401457.

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Cardoch, Sebastian. "Computational study of single protein sensing using nanopores". Thesis, Uppsala universitet, Materialteori, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-423441.

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Identifying the protein content in a cell in a fast and reliable manner has become a relevant goal in the field of proteomics. This thesis computationally explores the potential for silicon nitride nanopores to sense and distinguish single miniproteins, which are small domains that promise to facilitate the systematic study of larger proteins. Sensing and identification of these biomolecules using nanopores happens by studying modulations in ionic current during translocation. The approach taken in this work was to study two miniproteins of similar geometry, using a cylindrical-shaped pore. I employed molecular mechanics to compare occupied pore currents computed based on the trajectory of ions. I further used density functional theory along with relative surface accessibility values to compute changes in interaction energies for single amino acids and obtain relative dwell times. While the protein remained inside the nanopore, I found no noticeable differences in the occupied pore currents of the two miniproteins for systems subject to 0.5 and 1.0 V bias voltages. Dwell times were estimated based on the translocation time of a protein that exhibits no interaction with the pore walls. I found that both miniproteins feel an attractive force to the pore wall and estimated their relative dwell times to differ by one order of magnitude. This means even in cases where two miniproteins are indistinguishable by magnitude changes in the ionic current, the dwell time might still be used to identify them. This work was an initial investigation that can be further developed to increase the accuracy of the results and be expanded to assess other miniproteins with the goal to aid future experimental work.

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Han, Ling. "Physiology of Escherichia coli in batch and fed-batch cultures with special emphasis on amino acid and glucose metabolism". Doctoral thesis, KTH, Biotechnology, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3334.

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The objective of this work is to better understand themetabolism and physiology ofEscherichiacoli(W3110) in defined medium cultures with thelong-term goal of improving cell yield and recombinant proteinproductivity.

The order of amino acid utilization inE. colibatch cultures was investigated in a medium with16 amino acids and glucose. Ser, Pro, Asp, Gly, Thr, Glu andAla were rapidly consumed and depleted at the end of theexponential phase, while His, Arg, Val, Met, Ile, Leu, Phe, Lysand Tyr were consumed slowly during the following linear growthphase. The uptake order correlated to the maximum specificconsumption rate. Of the rapidly consumed amino acids onlyglyine and threonine improved growth when added individually.Serine was the first amino acid to be consumed, but inhibitedglucose uptake initially, which presumably is related to thefunction of PTS. Valine inhibited cell growth could be releasedby isoleucine. The critical medium concentration of valinetoxicity was 1.5 - 3 µmol L^-1. Valine uptake was associated with exchange ofisoleucine out of the cells.

Glycine significantly increased the cell yield,Y_x/s,and growth rate ofE. coliin batch cultures in a glucose-mineral medium.Maximum effect occurred at pH 6.8, at 6 - 12 mmol L^-1glycine, and below 1.15 g dw L^-1.¹³C NMR technique was employed to identify [1-¹³C], [2-¹³C]and [1,2-¹³C]acetate in the cultures supplied with [2-¹³C]glycine. The NMR data revealed that littledegradation of added glycine occurred, and that serine/glycinebiosynthesis was repressed below 1.15 g dw L^-1, implicating that glycine was a source ofglycine, serine, one-carbon units, and threonine. Above 1.15 gdw L^-1, 53% of the consumed glycine carbon was excretedas acetate. Degradation of glycine was associated with anincreased uptake rate, cleavage by GCV, and degradation of bothglycine- and glucose-derived serine to pyruvate. This switch inmetabolism appears to be regulated by quorum sensing.

A cell density-dependent metabolic switch occurred also inthe central metabolism. A 2 - 3 fold decrease in mostglycolytic and TCA cycle metabolites, but an increase inacetyl-CoA, occurred after the switch. The acetate productionrate decreased throughout the culture with a temporary increaseat the switch point, but the intracellular acetate poolremained relatively constant.

Two mixtures of amino acids were fed together with glucosein fed-batch cultures ofE. coliW3110 pRIT44T2, expressing the recombinantprotein ZZT2. One mixture contained 20 amino acids and theother 5 so-called 'protein amino acids': Ala, Arg, Met, His andPhe. Although the amino aids increased the cell yield anddecreased the proteolysis rate in both cases, ZZT2 productionwas decreased. A decrease of ZZT2 synthesis rate is consideredto be the reason. Further studies of the 5 amino acidsindicated that a few amino acids disturb metabolism.

Carbon mass balances were calculated in glucose limitedfed-batch cultures ofE. coli. In the end, the carbon recovery was ~90% basedon biomass, CO₂and acetate, but ~100% if the all carbon in themedium was included. Outer membrane (OM) constituents,lipopolysaccharide, phospholipids, and carbohydratescontributed to 63% of the extracellular carbon. Little celllysis occurred and the unidentified (~30%) carbon was assumedto constitute complex carbohydrates. A novel cultivationtechnique Temperature-Limited Fed-Batch (TLFB) is developed toprevent OM shedding in high-cell density cultures.

Keywords: Escherichia coli, amino acids, glycine, quorumsensing, metabolic switch, metabolite pools, carbon balance,outer membrane, lipopolysaccharide, batch culture, fed-batchculture

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Delescluse, Julie. "MND, un transporteur d’acides aminés, acteur clef de la réponse neuronale aux acides aminés des corps pédonculés, chez l’adulte Drosophila melanogaster". Electronic Thesis or Diss., Bourgogne Franche-Comté, 2024. http://www.theses.fr/2024UBFCK029.

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Chaque organisme vivant évolue dans son écosystème, où il doit être capable de détecter et d’intégrer de multiples facteurs environnementaux (température, hygrométrie, composés chimiques organiques ou non…). Ces signaux jouent un rôle important dans la communication entre organismes. Chaque individu doit donc mettre en lien ces stimuli externes avec ses propres signaux internes (nutritionnel, métabolique, hormonal, infection…), et adapter son comportement en conséquence pour assurer sa survie et sa reproduction. Pour ce faire des mécanismes complexes de détection se sont développés, notamment le système chimio-sensoriel, permettant la réception et la discrimination de molécules chimiques externes. En parallèle, des organes internes sont sensibles aux signaux internes afin de détecter des carences et de contrôler l’homéostasie cellulaire et tissulaire. Ces processus sont notamment possibles grâce à des protéines transmembranaires qui sont spécialisées dans la réception et/ou le transport d’autres molécules comme les acides aminés (AAs), indispensables à tous les types cellulaires tels que les cellules du système nerveux.Nos travaux de recherche montrent qu’un transporteur d’AAs appartenant à la famille des Solute carrier 7A (SLC7A) nommé Minidiscs (MND) est exprimé dans le cerveau adulte, au niveau des neurones et des cellules gliales. Cette protéine semble se localiser au niveau de la membrane plasmique et de la membrane du réticulum endoplasmique. MND est exprimé dans les neurones formant une structure particulière du cerveau appelée Corps Pédonculés (CPs) et joue un rôle clef dans la réponse de ces neurones à certains L-AAs (L-Asp, L-Arg, L-Glu, L-Lys, L-Ile, L-Leu et L-Thr). Ce résultat démontre ainsi que des transporteurs de la famille des SLC7As sont impliqués dans le contrôle de l’activité des neurones. De plus, cela suggère que les CPs peuvent détecter directement des L-AAs via MND, faisant de cette structure un centre de détection du statut interne nutritionnel de l’individu. La réponse de ces neurones à la L-Leucine MND dépendante fait intervenir la voie de signalisation passant par TOR, mais n’implique pas la Glutamate Deshydrogenase (GDH). Ainsi, MND pourrait potentiellement moduler les comportements associés à cette structure, tels que la mémoire olfactive, l’agressivité... Cependant, nos études comportementales semblent indiquer que la présence de MND dans tous les neurones des CPs n’est pas requise pour la modulation du comportement d’agressivité territoriale des mâles.Mes données indiquent également que MND est requis pour la réponse des CPs au L-Glutamate, qui est aussi un neurotransmetteur. MND étant décrit comme transporteur de L-AAs non chargés et que le L-Glutamate est, dans sa forme physiologique un AA chargé négativement, des partenaires de MND sont potentiellement impliqués dans cette activation. Cinq types de récepteurs au L-Glutamate sont présents dans les mêmes neurones des CPs exprimant MND : NMDAR1, NMDAR2, KAIR1D, mGluR et GluCl��. Il a été possible de montrer que l’activation des CPs via le récepteur NMDAR1 est dépendante de la présence de MND. Toutefois, cette voie de détection de signaux glutamatergiques ne semble pas intervenir dans la régulation du comportement d’agressivité. Nous montrons également que l’activité des CPs en réponse au glutamate qui est dépendante de NMDAR1 semble différer suivant le contexte social. En effet, une réponse plus intense a été observée chez les mâles isolés socialement par rapport aux mâles groupés. Cette réponse au glutamate impliquant NMDAR1 pourrait dépendre de la détection chronique du 11-cis-Vaccenyl Acétate (cVA), une phéromone mâle, suggérant ainsi que l’environnement social joue un rôle sur l’activité des CPs.Ainsi, pris dans leur ensemble, mes résultats montrent que des transporteurs d’acides aminés de type SLC interviennent dans la capacité des neurones à répondre aux AAs comme la L-Leucine et aux neurotransmetteurs comme le glutamate
Every living organism lives in an ecosystem, where it needs to detect and integrate multiple environmental factors (temperature, humidity, organic or non-organic chemical compounds...). These signals play an important role in communication between organisms. Each individual must link these external stimuli with its own internal signals (nutritional, metabolic, hormonal, infection...), and adapt its behavior to ensure its survival and reproduction. To achieve this, complex detection mechanisms have been developed, including the chemosensory system, allowing the reception and discrimination of external chemical molecules. Internal organs are sensitive to internal signals to detect deficiencies and control cellular and tissue homeostasis. These processes are made possible by transmembrane proteins that specialize in detection and/or transporting other molecules such as amino acids (AAs), essential for all cell types such as neuronal cells.My research focuses on an amino acid transporter belonging to the SLC7A family called Minidiscs (MND) and we showed that MND is expressed in the adult brain, in neurons and glial cells. This protein appears to be localized at the plasma membrane and the endoplasmic reticulum. MND is expressed in neurons forming a particular brain structure called Mushroom Bodies (MBs) and plays a key role in the response of these neurons to several L-amino acids (L-Asp, L-Arg, L-Glu, L-Lys, L-Ile, L-Leu, and L-Thr). This result demonstrates that SLC7A transporters are involved in controlling neuron activity and suggests that MBs can directly detect L-amino acids via MND. That making this structure a center for detecting the individual's internal nutritional status. The response of these neurons to L-Leucine MND-dependent involves a TOR pathway and not a GDH one. Due to its localization within the CPs, MND may potentially modulate behaviors associated with this structure. However, the presence of MND in all MB neurons is not required for modulation of male territorial aggressive behavior.My results also show that MND is required for the MBs' response to L-Glutamate which is also a neurotransmitter. MND is described as a transporter of uncharged L-amino acids and not L-Glutamate which is a negatively charged AA. Five L-Glutamate receptors are expressed in the MB neurons expressing MND: NMDAR1, NMDAR2, KAIR1D, mGluR, and GluCl��. We demonstrated that MB activation via the NMDAR1 receptor is MND dependent. This glutamatergic signaling pathway does not appear to be involved in the regulation of aggressive behavior. However, MB activity in response to glutamate involving NMDAR1 appears to be modulated by the social environment. Thus, the response of the MBs is increased in isolated males compared to grouped males. This glutamate response via NMDAR1 could depend on the chronic detection of 11-cis-Vaccenyl Acetate (cVA), a male pheromone. This suggesting that social environment impacts the MB activity.Thus, my results show that SLC-type amino acid transporters are involved in the ability of neurons to respond to neurotransmitters, such as glutamate and AAs

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Lucchesi, Pamela A. "Plasma Membrane Processes in Smooth Muscle: Characterization of Ca²⁺ Transport and Muscarinic Cholinergic Receptors: A Thesis". eScholarship@UMMS, 1989. https://escholarship.umassmed.edu/gsbs_diss/135.

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The thesis research was designed to study the characteristics of two important physiological processes in smooth muscle: Ca2+ transport mediated by the plasmalemmal Ca2+-ATPase and muscarinic receptor-G protein interactions. In resting smooth muscle, several Ca2+ extrusion or sequestration processes offset the passive inward leak of Ca2+. Although biochemical evidence suggests that the plasmalemmal Ca2+ pump plays a key role in this process, the precise role of this enzyme could not be proven until a reliable estimate of the inward Ca2+ leak was measured. Recent studies using dispersed smooth muscle cells from the toad stomach provided an estimate of the basal transmembrane Ca2+ flux rate; thus, we examined the transport capacity of the plasmalemmal Ca2+pump in this tissue. Gastric smooth muscle tissue was disrupted by homogenization and nitrogen cavitation. Membranes enriched 20 fold for plasma membrane markers were obtained using differential centrifugation and purification by flotation on discontinuous sucrose gradients. The membrane vesicles exhibited an ATP-dependent 45Ca uptake that was insensitive to azide or oxalate but sensitive to stimulation by calmodulin or inhibition by orthovanadate and the calmodulin antagonists trifluoperazine (TFP) or calmidazolium (CMZ). 45Ca accumulated in the presence of ATP was rapidly released by Ca2+ ionophore but not by agents that stimulate Ca2+ release from the sarcoplasmic rettculum (caffeine, inositol trisphosphate, GTP). However, both CMZ and TFP evoked a Ca2+ release that was comparable to that observed in the presence of Ca2+ ionophore, suggesting that these compounds have profound effects on membrane Ca2+permeability. 45Ca transport exhibited a high affinity for Ca2+ (KD 0.2 μM) and a high transport capacity, producing a > 12,000-fold gradient for Ca2+and a transmembrane flux rate at least 3-fold greater than that observed in resting smooth muscle cells. As a first step toward understanding the biochemical basis for the diversity of muscarinic cholinergic actions on smooth muscle, we examined the distribution of muscarinic receptor subtypes and coupling to guantne nucleotide-binding (G) proteins in airway and gastric smooth muscle. Receptor subtypes were classified in membranes prepared from bovine trachea and toad stomach based on the relative abilities of the selective antagonists pirenzepine (M1), AF-DX 116 (M2) and 4-DAMP (M3) to displace the binding of nonselective antagonist [3H]QNB (quinuclidinyl benzilate). Based on the binding profiles for these antagonists, it was concluded that both smooth muscle types contain a mixture of M2 and M3 subtypes. In trachea the majority of receptors (86%) were M2, whereas in stomach the majority of receptors (88%) were M3. The displacement of [3H]QNB binding by the agonist oxotremorine indicated a mixed population of high affinity (KD = 4 nM) and low affinity (KD = 2-4 μM) binding sites. The addition of GTPγS abolished all high affinity agonist binding, suggesting that coupling of the receptors to G proteins may confer high affinity. Reaction of membranes with pertussis toxin in the presence of [32P]NAD caused the [32P]-labelling of a ~ 41 kD protein in both gastric and tracheal smooth musc1e. Pretreatment of the membranes with pertussis toxin and NAD completely abolished high affinity agonist binding in gastric smooth muscle, but produced little if any decrease in high affinity agonist binding in trachea. We conclude that, although muscarinic receptor activation leads to the elevation of intracellular Ca2+ and to contraction of both airway and gastric smooth muscle, the dissimilar distributions of receptor subtypes and distinct patterns of coupling to G proteins may indicate that each smooth muscle type uses different receptor-G protein interactions to regulate intracellular signalling pathways.

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Libri sul tema "Amino acids sensing"

Stibor, Ivan. Anion Sensing. Springer, 2014.

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Kirchman, David L. Symbioses and microbes. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198789406.003.0014.

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The book ends with a chapter devoted to discussing interactions between microbes and higher plants and animals. Symbiosis is sometimes used to describe all interactions, even negative ones, between organisms in persistent, close contact. This chapter focuses on interactions that benefit both partners (mutualism), or one partner while being neutral to the other (commensalism). Microbes are essential to the health and ecology of vertebrates, including Homo sapiens. Microbial cells outnumber human cells on our bodies, aiding in digestion and warding off pathogens. In consortia similar to the anaerobic food chain of anoxic sediments, microbes are essential in the digestion of plant material by deer, cattle, and sheep. Different types of microbes form symbiotic relationships with insects and help to explain their huge success in the biosphere. Protozoa are crucial for wood-boring insects, symbiotic bacteria in the genus Buchnera provide sugars to host aphids while obtaining essential amino acids in exchange, and fungi thrive in subterranean gardens before being harvested for food by ants. Symbiotic dinoflagellates directly provide organic material to support coral growth in exchange for ammonium and other nutrients. Corals are now threatened worldwide by rising oceanic temperatures, decreasing pH, and other human-caused environmental changes. At hydrothermal vents in some deep oceans, sulfur-oxidizing bacteria fuel an entire ecosystem and endosymbiotic bacteria support the growth of giant tube worms. Higher plants also have many symbiotic relationships with bacteria and fungi. Symbiotic nitrogen-fixing bacteria in legumes and other plants fix more nitrogen than free-living bacteria. Fungi associated with plant roots (“mycorrhizal”) are even more common and potentially provide plants with phosphorus as well as nitrogen. Symbiotic microbes can provide other services to their hosts, such as producing bioluminescence, needed for camouflage against predators. In the case of the bobtail squid, bioluminescence is only turned on when populations of the symbiotic bacteria reach critical levels, determined by a quorum sensing mechanism.

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Capitoli di libri sul tema "Amino acids sensing"

Gutiérrez-Juárez, Roger. "Regulation of Liver Glucose Metabolism by the Metabolic Sensing of Leucine in the Hypothalamus". In Branched Chain Amino Acids in Clinical Nutrition, 75–86. New York, NY: Springer New York, 2015. http://dx.doi.org/10.1007/978-1-4939-1923-9_7.

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Periasamy, Selvakannan, Deepa Dumbre, Libitha Babu, Srinivasan Madapusi, Sarvesh Kumar Soni, Hemant Kumar Daima e Suresh Kumar Bhargava. "Amino Acids Functionalized Inorganic Metal Nanoparticles: Synthetic Nanozymes for Target Specific Binding, Sensing and Catalytic Applications". In Environmental Chemistry for a Sustainable World, 1–33. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-68230-9_1.

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Li, Peng, e Guoyao Wu. "Characteristics of Nutrition and Metabolism in Dogs and Cats". In Nutrition and Metabolism of Dogs and Cats, 55–98. Cham: Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-54192-6_4.

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AbstractDomestic dogsand cats have evolved differentially in some aspects of nutrition, metabolism, chemical sensing, and feedingbehavior. The dogs have adapted to omnivorous dietscontaining taurine-abundant meat and starch-rich plant ingredients. By contrast, domestic catsmust consumeanimal-sourced foodsfor survival, growth, and development. Both dogsand catssynthesize vitamin C and many amino acids (AAs, such as alanine, asparagine, aspartate, glutamate, glutamine, glycine, proline, and serine), but have a limited ability to form de novo arginineand vitamin D3. Compared with dogs, cats have greater endogenousnitrogen losses and higher dietary requirements for AAs (particularly arginine, taurine, and tyrosine), B-complex vitamins (niacin, thiamin, folate, and biotin), and choline; exhibit greater rates of gluconeogenesis; are less sensitive to AA imbalances and antagonism; are more capable of concentrating urine through renal reabsorption of water; and cannot tolerate high levels of dietary starch due to limited pancreatic α-amylase activity. In addition, dogs can form sufficient taurinefrom cysteine(for most breeds); arachidonic acidfrom linoleic acid; eicosapentaenoic acid and docosahexaenoic acid from α-linolenic acid; all-trans-retinol from β-carotene; and niacinfrom tryptophan. These synthetic pathways, however, are either absent or limited in all cats due to (a) no or low activities of key enzymes (including pyrroline-5-carboxylate synthase, cysteinedioxygenase, ∆6-desaturase, β-carotene dioxygenase, and quinolinate phosphoribosyltransferase) and (b) diversion of intermediates to other metabolic pathways. Dogs can thrive on one large meal daily, select high-fat over low-fat diets, and consume sweet substances. By contrast, cats eat more frequently during light and dark periods, select high-protein over low-protein diets, refuse dryfood, enjoy a consistent diet, and cannot taste sweetness. This knowledge guides the feeding and care of dogsand cats, as well as the manufacturing of their foods. As abundant sources of essentialnutrients, animal-derivedfoodstuffs play important roles in optimizing the growth, development, and health of the companionanimals.

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Parker, Francine, Eulashini Chuntharpursat-Bon, Justin E. Molloy e Michelle Peckham. "Using FRET to Determine How Myo10 Responds to Force in Filopodia". In Mechanobiology, 67–77. Cham: Springer International Publishing, 2024. http://dx.doi.org/10.1007/978-3-031-45379-3_4.

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Abstract.Myosin 10 (Myo10) is an actin-based molecular motor that is essential for filopodia formation and likely senses tension through interactions with integrins in filopodial tips. It possesses a single α-helical (SAH) domain at the end of its canonical lever, which amplifies the movement of the motor. We have shown the SAH domain can contribute to lever function and possesses the properties of a constant force spring. Here we investigate whether the SAH domain plays a role in tension sensing and whether it becomes extended under load at the filopodial tip. Previously, we found that removing the entire SAH domain and short anti-parallel coiled coil (CC) region at the C-terminal end of the SAH does not prevent Myo10 from moving to filopodial tips in cells. Exploiting this, we generated recombinant forms of Myo10, in which a tension-sensing module (TSMod), comprising a FRET-pair YPet and mCherry separated by a linker sequence of amino acids was then inserted between the Myo10 motor and tail domains, so as to replace the SAH domain and CC region. The linker sequence comprised either a portion of the native SAH domain, or control sequences that were either short (x1: stiff) or long (x5: flexible) repeats of “GPGGA”. As additional controls we also placed the TSMod construct at the N-terminus, where it should not experience force. Our FRET measurements indicate that the SAH domain of Myo10 may become extended at when the protein is stalled at the filopodial tips, so the SAH domain may therefore act as a force sensor.

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Gietzen, D. W., S. Hao e T. G. Anthony. "Amino Acid-Sensing Mechanisms: Biochemistry and Behavior". In Handbook of Neurochemistry and Molecular Neurobiology, 249–69. Boston, MA: Springer US, 2007. http://dx.doi.org/10.1007/978-0-387-30374-1_10.

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Marmelstein, Alan M., Javier Moreno e Dorothea Fiedler. "Chemical Approaches to Studying Labile Amino Acid Phosphorylation". In Phosphate Labeling and Sensing in Chemical Biology, 179–210. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-60357-5_7.

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Şener, Gülsu, e Adil Denizli. "Colorimetric Sensor Array Based on Amino Acid-Modified Gold Nanoparticles for Toxic Metal Ion Detection in Water". In Biomimetic Sensing, 75–80. New York, NY: Springer New York, 2019. http://dx.doi.org/10.1007/978-1-4939-9616-2_6.

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Torii, K., e T. Tsurugizawa. "Brain Amino Acid Sensing". In The Molecular Nutrition of Amino Acids and Proteins, 331–40. Elsevier, 2016. http://dx.doi.org/10.1016/b978-0-12-802167-5.00024-4.

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Manoj, Devaraj, Saravanan Rajendran, Manoharan Murphy e Mohana Marimuthu. "Graphene-based Nanocomposites for Amino Acid Sensing". In Graphene-based Nanocomposite Sensors, 369–93. Royal Society of Chemistry, 2023. http://dx.doi.org/10.1039/bk9781837671847-00369.

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Thanks to the intriguing thermal, electrical and mechanical properties offered by graphene by which the potential applications now extend over a wide range, from electronic devices to wearable patches. For biosensor development, in particular, various graphene-based composites have been fruitfully used in different forms, e.g. as electrode substrates, molecular hybrids, patterned films and biocompatible platforms. In the past couple of years, a significant number of reports have been devoted to graphene-based nanocomposites for electrochemical sensing of small biomolecules such as amino acids. Because of its outstanding conductivity, hydrophilicity, abundant functional groups, large surface area, and high chemical and thermal stability, graphene-based nanocomposites as electrode supports can act as a conductive platform for signal improvement for single amino acids or for two or more amino acids simultaneously. Therefore, it is essential for researchers to acknowledge the recent design and developments of graphene-based nanocomposites for sensing amino acids and derived neurotransmitters. The present chapter aims to highlight the importance of amino acids and their role in the human body and the various analytical methods employed for their effective detection. We will also highlight the reports on various graphene-based nanocomposites as electrode materials for the sensing of various amino acids such as cysteine, tryptophan and tyrosine. Finally, we will also conclude the chapter with remarks and perspectives for future development of smart sensing devices.

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Zahid Farooq, Muhammad, e Hafiz Ishfaq Ahmad. "Sensing of Nutrients and the State of Sensors for the mTORC1 Pathway that are Controlled by Amino Acids". In Recent Trends In Livestock Innovative Technologies, 116–25. BENTHAM SCIENCE PUBLISHERS, 2023. http://dx.doi.org/10.2174/9789815165074123070011.

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The mechanistic target of rapamycin (mTORC1) is an expert cell production controller which reacts to a different set of natural information sources, such as amino acids. Various proteins have been differentiated recently to help communicate amino acid accessibility to mTORC1. Rag guanosine triphosphatases (GTPases) transfer amino acid accessibility to the mTORC1 duct, and the mTORC1 apprentice to the amino acid on the Lysosome in a conventional manner. Later on, several sensors were exposed for the amino acid-reinforced mTORC1 pathway, including Leucine, Argina, and S-adenosyl methionine. The representation of these sensors is essential to explain why cells change the pathways of amino acid detection requirements. Here, we survey these new advances and feature the assortment of further inquiries that rise out of the recognizable proof of these sensors.

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Atti di convegni sul tema "Amino acids sensing"

Xin, Lianxin, Jie Hou, Aleem Sayles, Jian Zhao, Aristides Marcano, Hui Xia e Jun Ren. "Raman spectral analyses of amino acids in life processes". In Optical Diagnostics and Sensing XIX: Toward Point-of-Care Diagnostics, a cura di Gerard L. Coté. SPIE, 2019. http://dx.doi.org/10.1117/12.2509883.

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Bader, Michael, Dankwart Rauscher, Kurt Geibel e Juergen Angerer. "Biomonitoring of carcinogenic substances: enzymatic digestion of globin for detecting alkylated amino acids". In Environmental Sensing '92, a cura di Tuan Vo-Dinh e Karl Cammann. SPIE, 1993. http://dx.doi.org/10.1117/12.140257.

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Heng Zhang. "Determination of twenty amino acids by ninhydrin reaction with FIA". In 2011 International Conference on Remote Sensing, Environment and Transportation Engineering (RSETE). IEEE, 2011. http://dx.doi.org/10.1109/rsete.2011.5965907.

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Rosen, David L., e James B. Gillespie. "Atmospheric extinction effect on remote chemical sensing". In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1989. http://dx.doi.org/10.1364/oam.1989.tuu8.

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Laser-induced fluorescence (LIF) is sometimes used for lidar because of the sensitivity of LIF spectra to chemical composition. Because of aerosols, background fluorescence, and quenching associated with the boundary layer, most LIF lidar studies have been restricted to simple gases above the troposphere. We performed a computer simulation to show the feasibility of applying UV fluorescence lidar to the chemical analysis of aerosols and hard targets in the troposphere. We applied factor analysisrank annihilation (FARA) techniques to a numerically generated excitation-emission matrix (EEM) of a mixture of amino acids. The EEM of the mixture was modified to include atmospheric extinction. The calculated concentrations of the amino acids were greatly reduced by extinction. This shows that the LIF spectrum must be deconvolved from the atmospheric extinction spectrum to properly interpret UV fluorescence lidar returns.

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Sang, Yaxin, Changlu Wang e Li Wang. "Study on amino acids chelating calcium prepared by shellfish processing by-products". In 2011 International Conference on Remote Sensing, Environment and Transportation Engineering (RSETE 2011). IEEE, 2011. http://dx.doi.org/10.1109/rsete.2011.5965801.

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Thobakgale, Setumo Lebogang, Satuurnin Ombinda Lemboumba e Patience Mthunzi-Kufa. "Investigation and calibration of non-essential amino acids using a custom built Raman spectroscopy system". In Optical Diagnostics and Sensing XIX: Toward Point-of-Care Diagnostics, a cura di Gerard L. Coté. SPIE, 2019. http://dx.doi.org/10.1117/12.2509839.

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Acosta-Maeda, Tayro E., Anupam K. Misra, Shiv K. Sharma, M. Nurul Abedin, Lloyd G. Muzangwa e Genesis Berlanga. "Stand-off detection of amino acids and nucleic bases using a compact instrument as a tool for search for life". In Lidar Remote Sensing for Environmental Monitoring XVI, a cura di Nobuo Sugimoto e Upendra N. Singh. SPIE, 2018. http://dx.doi.org/10.1117/12.2324827.

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Nguyen, Tyler, e Mitchio Nemchick, Okumura. "QUANTUM CASCADE LASER-BASED INFRARED PHOTODISSOCIATION ACTION SPECTROSCOPY OF HYDRATED AMINO ACIDS FOR PLANETARY SCIENCE IN SITU SENSING APPLICATIONS". In 2023 International Symposium on Molecular Spectroscopy. Urbana, Illinois: University of Illinois at Urbana-Champaign, 2023. http://dx.doi.org/10.15278/isms.2023.6816.

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Shukri, Nafeesa S., Zaharah Johari, N. Ezaila Alias, N. Aini Zakaria e M. F. M. Yusoff. "Improved Sensing Properties of Amino Acid on Black Phosphorene: A Computational Study". In 2019 IEEE International Conference on Sensors and Nanotechnology (SENSORS & NANO). IEEE, 2019. http://dx.doi.org/10.1109/sensorsnano44414.2019.8940053.

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Liu, Wei, Sixing Xu, Binmeng Hu e Xiaohong Wang. "A novel potential modulated amino acid sensing chip modified by MXene for total internal reflection imaging ellipsometry biosensor". In 2018 IEEE Micro Electro Mechanical Systems (MEMS). IEEE, 2018. http://dx.doi.org/10.1109/memsys.2018.8346558.

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Rapporti di organizzazioni sul tema "Amino acids sensing"

Spalding, Edgar P. Amino acid-sensing ion channels in plants. Office of Scientific and Technical Information (OSTI), agosto 2014. http://dx.doi.org/10.2172/1149488.

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Wisniewski, Michael, Samir Droby, John Norelli, Dov Prusky e Vera Hershkovitz. Genetic and transcriptomic analysis of postharvest decay resistance in Malus sieversii and the identification of pathogenicity effectors in Penicillium expansum. United States Department of Agriculture, gennaio 2012. http://dx.doi.org/10.32747/2012.7597928.bard.

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Use of Lqh2 mutants (produced at TAU) and rNav1.2a mutants (produced at the US side) for identifying receptor site-3: Based on the fact that binding of scorpion alpha-toxins is voltage-dependent, which suggests toxin binding at the mobile voltage-sensing region, we analyzed which of the toxin bioactive domains (Core-domain or NC-domain) interacts with the DIV Gating-module of rNav1.2a. This analysis was based on the assumption that the dissociation of toxin mutants upon depolarization would vary from that of the unmodified toxin should the substitutions affect a site of interaction with the channel Gating-module. Using a series of toxin mutants (mutations at both domains) and two channel mutants that were shown to reduce the sensitivity to scorpion alpha-toxins, and by comparison of depolarization-driven dissociation of Lqh2 derivatives off their binding site at rNav1.2a mutant channels we found that the toxin Core-domain interacts with the Gating-module of DIV. Details of the experiments and results appear in Guret al (2011). Mapping receptor site 3 at Nav1.2a by extensive channel mutagenesis (Seattle): Since previous studies with photoaffinity labeling and antibody mapping implicated domains I and IV in scorpion alpha-toxin binding, Nav1.2 channel mutants containing substitutions at these extracellular regions were expressed and tested for receptor function by whole-cell voltage clamp. Of a large number of channel mutants, T1560A, F1610A, and E1613A in domain IV had ~5.9-, ~10.7-, and ~3.9-fold lower affinities for the scorpion toxin Lqh2, respectively, and mutant E1613R had 73-fold lower affinity. Toxin dissociation was accelerated by depolarization for both wild-type and mutants, and the rates of dissociation were also increased by mutations T1560A, F1610A and E1613A. In contrast, association rates for these three mutant channels at negative membrane potentials were not significantly changed and were not voltage-dependent. These results indicated that Thr1560 in the S1-S2 loop, Phe1610 in the S3 segment, and Glu1613 in the S3-S4 loop in domain IV participate in toxin binding. T393A in the SS2-S6 loop in domain I also showed a ~3.4-fold lower affinity for Lqh2, indicating that this extracellular loop may form a secondary component of the toxin binding site. Analysis with the Rosetta-Membrane algorithm revealed a three-dimensional model of Lqh2 binding to the voltage sensor in a resting state. In this model, amino acid residues in an extracellular cleft formed by the S1-S2 and S3-S4 loops in domain IV that are important for toxin binding interact with amino acid residues on two faces of the wedge-shaped Lqh2 molecule that are important for toxin action. The conserved gating charges in the S4 transmembrane segment are in an inward position and likely form ion pairs with negatively charged amino acid residues in the S2 and S3 segments (Wang et al 2011; Gurevitz 2012; Gurevitzet al 2013).

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