scholarly journals Role of the Novel Peptide Phoenixin in Stress Response and Possible Interactions with Nesfatin-1

2021 ◽  
Vol 22 (17) ◽  
pp. 9156
Author(s):  
Tiemo Friedrich ◽  
Andreas Stengel
Keyword(s):  
Small Intestine ◽  
Amino Acid ◽  
Restraint Stress ◽  
The Novel ◽  
Stress Reactions ◽  
Brain Nuclei ◽  
Physiological Functions ◽  
Physiological Processes ◽  
Recent Developments

The novel peptide phoenixin was shown to be involved in several physiological processes ranging from reproduction to food intake. Interest in this protein has steadily increased over the last few years and its known implications have become much broader, playing a role in glucose homeostasis, anxiety, nociception, and pruritus. Phoenixin is expressed in a multitude of organs such as the small intestine, pancreas, and in the hypothalamus, as well as several other brain nuclei influencing numerous physiological functions. Its highly conserved amino-acid sequence amongst species leads to the assumption, that phoenixin might be involved in essential physiological functions. Its co-expression and opposing functionality to the extensively studied peptide nesfatin-1 has given rise to the idea of a possible counterbalancing role. Several recent publications focused on phoenixin’s role in stress reactions, namely restraint stress and lipopolysaccharide-induced inflammation response, in which also nesfatin-1 is known to be altered. This review provides an overview on the phoenixins and nesfatin-1 properties and putative effects, and especially highlights the recent developments on their role and interaction in the response to response.

Role of membrane transport in interorgan amino acid flow between muscle and small intestine

Metabolism ◽  
1995 ◽  
Vol 44 (6) ◽  
pp. 719-724 ◽  
Author(s):  
Gianni Biolo ◽  
Xiao-Jun Zhang ◽  
Robert R. Wolfe
Keyword(s):  
Small Intestine ◽  
Amino Acid ◽  
Membrane Transport

scholarly journals A Novel, WidespreadqacAAllele Results in Reduced Chlorhexidine Susceptibility inStaphylococcus epidermidis

2019 ◽  
Vol 63 (6) ◽  
Author(s):  
Amin Addetia ◽  
Alexander L. Greninger ◽  
Amanda Adler ◽  
Shuhua Yuan ◽  
Negar Makhsous ◽  
...  
Keyword(s):  
Amino Acid ◽  
Staphylococcus Epidermidis ◽  
Sequence Data ◽  
Methicillin Resistance ◽  
Single Amino Acid ◽  
Data Sets ◽  
The Novel ◽  
Content Type

ABSTRACTChlorhexidine gluconate (CHG) is a topical antiseptic widely used in health care settings. InStaphylococcusspp., the pump QacA effluxes CHG, while the closely related QacB cannot due to a single amino acid substitution. We characterized 1,050 cutaneousStaphylococcusisolates obtained from 173 pediatric oncology patients enrolled in a multicenter CHG bathing trial. CHG susceptibility testing revealed that 63 (6%) of these isolates had elevated CHG MICs (≥4 μg/ml). Screening of all 1,050 isolates for theqacA/Bgene (the sameqacgene with A or B allele) by restriction fragment length polymorphism (RFLP) yielded 56 isolates with a novelqacA/BRFLP pattern,qacA/B273. The CHG MIC was significantly higher forqacA/B273-positive isolates (MIC50, 4 μg/ml; MIC range, 0.5 to 4 μg/ml) than for otherqacgroups:qacA-positive isolates (n = 559; MIC50, 1 μg/ml; MIC range, 0.5 to 4 μg/ml),qacB-positive isolates (n = 17; MIC50, 1 μg/ml; MIC range, 0.25 to 2 μg/ml), andqacA/B-negative isolates (n = 418, MIC50, 1 μg/ml; MIC range, 0.125 to 2 μg/ml) (P = 0.001). A high proportion of theqacA/B273-positive isolates also displayed methicillin resistance (96.4%) compared to the otherqacgroups (24.9 to 61.7%) (P = 0.001). Whole-genome sequencing revealed thatqacA/B273-positive isolates encoded a variant of QacA with 2 amino acid substitutions. This new allele, namedqacA4, was carried on the novel plasmid pAQZ1. TheqacA4-carrying isolates belonged to the highly resistantStaphylococcus epidermidissequence type 2 clone. By searching available sequence data sets, we identified 39 additionalqacA4-carryingS. epidermidisstrains from 5 countries. Curing an isolate ofqacA4resulted in a 4-fold decrease in the CHG MIC, confirming the role ofqacA4in the elevated CHG MIC. Our results highlight the importance of further studyingqacA4and its functional role in clinical staphylococci.

scholarly journals The structural bases for agonist diversity in anArabidopsis thalianaglutamate receptor-like channel

2019 ◽  
Vol 117 (1) ◽  
pp. 752-760 ◽  
Author(s):  
Andrea Alfieri ◽  
Fabrizio G. Doccula ◽  
Riccardo Pederzoli ◽  
Matteo Grenzi ◽  
Maria Cristina Bonza ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Ligand ◽  
Physiological Processes ◽  
Structural Framework ◽  
Seedling Roots ◽  
Wound Signaling ◽  
Unique Amino Acid ◽  
Sulfur Containing

Arabidopsis thalianaglutamate receptor-like (GLR) channels are amino acid-gated ion channels involved in physiological processes including wound signaling, stomatal regulation, and pollen tube growth. Here, fluorescence microscopy and genetics were used to confirm the central role of GLR3.3 in the amino acid-elicited cytosolic Ca2+increase inArabidopsisseedling roots. To elucidate the binding properties of the receptor, we biochemically reconstituted the GLR3.3 ligand-binding domain (LBD) and analyzed its selectivity profile; our binding experiments revealed the LBD preference forl-Glu but also for sulfur-containing amino acids. Furthermore, we solved the crystal structures of the GLR3.3 LBD in complex with 4 different amino acid ligands, providing a rationale for how the LBD binding site evolved to accommodate diverse amino acids, thus laying the grounds for rational mutagenesis. Last, we inspected the structures of LBDs from nonplant species and generated homology models for other GLR isoforms. Our results establish that GLR3.3 is a receptor endowed with a unique amino acid ligand profile and provide a structural framework for engineering this and other GLR isoforms to investigate their physiology.

scholarly journals Nickel(II) complexes based on L-amino-acid-derived ligands: synthesis, characterization and study of the role of the supramolecular structure in carbon dioxide capture

2020 ◽  
Vol 76 (5) ◽  
pp. 825-838
Author(s):  
Andrea Rivas Marquina ◽  
Federico Movilla ◽  
Olga Carolina Sánchez Montilva ◽  
Eva Rentschler ◽  
Luca Carrella ◽  
...  
Keyword(s):  
Amino Acid ◽  
Supramolecular Structure ◽  
Crystal Packing ◽  
Carbon Dioxide Capture ◽  
Exchange Interactions ◽  
The Novel ◽  
Ferromagnetic Exchange ◽  
Magnetization Data ◽  
Structural Database

The formation of the symmetrical μ3-carbonate-bridged self-assembled trinuclear NiII complex Na2{[Ni(LO)2(H2O)]3(μ3-CO3)} (LO is the carboxylate anion of a L-tyrosine derivative), involves atmospheric CO2 uptake. The asymmetric unit of the complex comprises an octahedral coordination for the NiII with two L-tyrosine-based ligands, a water molecule and one O atom of the carbonate bridge. The Ni3–μ3-CO3 core in this compound is the first reported of this kind according to the Cambridge Structural Database (CSD). The supramolecular structure is mainly sustained by hydrogen bonds developed by the phenolic functionality of the L-tyrosine moiety of one ligand and the carboxylate group of a neighbouring ligand. The crystal packing is then characterized by three interpenetrated supramolecular helices associated with a diastereoisomer of the type R-sup P, which is essential for the assembly process. Magnetic susceptibility and magnetization data support weak ferromagnetic exchange interactions within the novel Ni3–μ3-CO3 core. The NiII complex obtained under the same synthetic conditions but using the analogous ligand derived from the amino acid L-phenylalanine instead of L-tyrosine gives rise to to a mononuclear octahedral system. The results obtained for the different complexes demonstrate the role of the supramolecular structure regarding the CO2 uptake property for these NiII–amino-acid-based systems.

scholarly journals Performance of temporal and spatial ICA in identifying and removing low-frequency physiological and motion effects in resting-state fMRI

2021 ◽  
Author(s):  
Ali Golestani ◽  
J. Jean Chen
Keyword(s):  
Resting State ◽  
Spatial Information ◽  
Hybrid Approach ◽  
Low Frequency ◽  
Resting State Fmri ◽  
Lower Amount ◽  
The Novel ◽  
Noise Sources ◽  
Physiological Processes ◽  
Recent Developments

Effective separation of signal from noise (including physiological processes and head motion) is one of the chief challenges for improving the sensitivity and specificity of resting-state fMRI (rs-fMRI) measurements and has a profound impact when these noise sources vary between populations. Independent component analysis (ICA) is an approach for addressing these challenges. Conventionally, due to the lower amount of temporal than spatial information in rs-fMRI data, spatial ICA (sICA) is the method of choice. However, with recent developments in accelerated fMRI acquisitions, the temporal information is becoming enriched to the point that the temporal ICA (tICA) has become more feasible. This is particularly relevant as physiological processes and motion exhibit very different spatial and temporal characteristics when it comes to rs-fMRI applications, leading us to conduct a comparison of the performance of sICA and tICA in addressing these types of noise. In this study, we embrace the novel practice of using theory (simulations) to guide our interpretation of empirical data. We find empirically that sICA can identify more noise-related signal components than tICA. However, on the merit of functional-connectivity results, we find that while sICA is more adept at reducing whole-brain motion effects, tICA performs better in dealing with physiological effects. These interpretations are corroborated by our simulation results. The overall message of this study is that if ICA denoising is to be used for rs-fMRI, there is merit in considering a hybrid approach in which physiological and motion-related noise are each corrected for using their respective best-suited ICA approach.

scholarly journals Amino acid transporters in the regulation of insulin secretion and signalling

2019 ◽  
Vol 47 (2) ◽  
pp. 571-590 ◽  
Author(s):  
Kiran Javed ◽  
Stephen J. Fairweather
Keyword(s):  
Amino Acids ◽  
Small Intestine ◽  
Insulin Secretion ◽  
Amino Acid ◽  
Insulin Signalling ◽  
Amino Acid Transporter ◽  
Fibroblast Growth Factor 21 ◽  
Amino Acid Transporters ◽  
Acid Transporter

Abstract Amino acids are increasingly recognised as modulators of nutrient disposal, including their role in regulating blood glucose through interactions with insulin signalling. More recently, cellular membrane transporters of amino acids have been shown to form a pivotal part of this regulation as they are primarily responsible for controlling cellular and circulating amino acid concentrations. The availability of amino acids regulated by transporters can amplify insulin secretion and modulate insulin signalling in various tissues. In addition, insulin itself can regulate the expression of numerous amino acid transporters. This review focuses on amino acid transporters linked to the regulation of insulin secretion and signalling with a focus on those of the small intestine, pancreatic β-islet cells and insulin-responsive tissues, liver and skeletal muscle. We summarise the role of the amino acid transporter B0AT1 (SLC6A19) and peptide transporter PEPT1 (SLC15A1) in the modulation of global insulin signalling via the liver-secreted hormone fibroblast growth factor 21 (FGF21). The role of vesicular vGLUT (SLC17) and mitochondrial SLC25 transporters in providing glutamate for the potentiation of insulin secretion is covered. We also survey the roles SNAT (SLC38) family and LAT1 (SLC7A5) amino acid transporters play in the regulation of and by insulin in numerous affective tissues. We hypothesise the small intestine amino acid transporter B0AT1 represents a crucial nexus between insulin, FGF21 and incretin hormone signalling pathways. The aim is to give an integrated overview of the important role amino acid transporters have been found to play in insulin-regulated nutrient signalling.

scholarly journals Structural and biochemical characterization of the novel CTX-M-151 extended-spectrum β-lactamase and its inhibition by Avibactam

2021 ◽  
Author(s):  
Barbara Ghiglione ◽  
María Margarita Rodríguez ◽  
Florencia Brunetti ◽  
Krisztina M. Papp-Wallace ◽  
Ayumi Yoshizumi ◽  
...  
Keyword(s):  
Amino Acid ◽  
Biochemical Characterization ◽  
Sequence Divergence ◽  
Chair Conformation ◽  
Amino Acid Identity ◽  
The Novel ◽  
Proton Relay ◽  
Low Degree

The diazabicyclooctane (DBO) inhibitor, avibactam (AVI), reversibly inactivates most serine-β-lactamases including the CTX-M β-lactamases. Currently, more than 230 CTX-M unique members distributed in five clusters with less than 5% amino acid sequence divergence within each group are described. Recently, a variant named as CTX-M-151 was isolated from a Salmonella Choleraesuis strain in Japan. This variant possesses a low degree amino acid identity with the other CTX-Ms (63.2-69.7% with respect to the mature proteins), and thus it may represent a new sub-group within the family. CTX-M-151 hydrolyzes ceftriaxone better than ceftazidime (kcat/Km values 6,000-fold higher), as observed with CTX-Ms. CTX-M-151 is well inhibited by mechanism-based inhibitors like clavulanic acid (kinact/KI = 0.15 μM−1.s−1). For AVI, Ki app (0.4 μM) was comparable to KPC-2; k2/K (37,000 M−1s−1) was lower than for CTX-M-15, while the koff (0.0015 s−1) was 2-14-fold faster than other class A β-lactamases. The structure of the CTX-M-151/AVI complex (1.32 Å) reveals that AVI adopts a chair conformation with hydrogen bonds between the AVI carbamate and Ser70 and Ser237 at the oxyanion hole. Upon acylation, the side chain of Lys73 points towards Ser130 which is associated with the protonation of Glu166, supporting the role of Lys73 in the proton-relay pathway and Glu166 as the general base in deacylation. To our knowledge, this is the first chromosomally-encoded CTX-M in Salmonella Choleraesuis that shows similar hydrolytic preference towards cefotaxime/ceftriaxone when compared to ceftazidime.

Electron probe x-ray microanalysis and electron microscopy of amino acid absorption and transport by the small intestine: inhibition by chemical poisons and correlation to the elemental composition of the epithelial cells

1986 ◽  
Vol 44 ◽  
pp. 134-135
Author(s):  
A. J. Tousimis
Keyword(s):  
Small Intestine ◽  
Amino Acid ◽  
Epithelial Cells ◽  
Elemental Composition ◽  
Isotope Labeling ◽  
Structural Components ◽  
X Ray ◽  
Human Small Intestine ◽  
Transport Studies

The elemental composition of amino acids is similar to that of the major structural components of the epithelial cells of the small intestine and other tissues. Therefore, their subcellular localization and concentration measurements are not possible by x-ray microanalysis. Radioactive isotope labeling: I131-tyrosine, Se75-methionine and S35-methionine have been successfully employed in numerous absorption and transport studies. The latter two have been utilized both in vitro and vivo, with similar results in the hamster and human small intestine. Non-radioactive Selenomethionine, since its absorption/transport behavior is assumed to be the same as that of Se75- methionine and S75-methionine could serve as a compound tracer for this amino acid.

How do histone modifications contribute to transgenerational epigenetic inheritance in C. elegans?

2020 ◽  
Vol 48 (3) ◽  
pp. 1019-1034 ◽  
Author(s):  
Rachel M. Woodhouse ◽  
Alyson Ashe
Keyword(s):  
Histone Modifications ◽  
Molecular Mechanisms ◽  
Epigenetic Inheritance ◽  
Nematode Caenorhabditis Elegans ◽  
Histone Methyltransferases ◽  
Transgenerational Epigenetic Inheritance ◽  
C Elegans ◽  
Recent Developments ◽  
Gene Regulatory

Gene regulatory information can be inherited between generations in a phenomenon termed transgenerational epigenetic inheritance (TEI). While examples of TEI in many animals accumulate, the nematode Caenorhabditis elegans has proven particularly useful in investigating the underlying molecular mechanisms of this phenomenon. In C. elegans and other animals, the modification of histone proteins has emerged as a potential carrier and effector of transgenerational epigenetic information. In this review, we explore the contribution of histone modifications to TEI in C. elegans. We describe the role of repressive histone marks, histone methyltransferases, and associated chromatin factors in heritable gene silencing, and discuss recent developments and unanswered questions in how these factors integrate with other known TEI mechanisms. We also review the transgenerational effects of the manipulation of histone modifications on germline health and longevity.

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