scholarly journals Oral and pre-absorptive sensing of amino acids relates to hypothalamic control of food intake in rainbow trout

2020 ◽  
Vol 223 (17) ◽  
pp. jeb221721
Author(s):  
Sara Comesaña ◽  
Marta Conde-Sieira ◽  
Cristina Velasco ◽  
José L. Soengas ◽  
Sofia Morais

ABSTRACTTo assess the putative role of taste and pre-absorptive sensing of amino acids in food intake control in fish, we carried out an oral administration with l-leucine, l-valine, l-proline or l-glutamic acid in rainbow trout (Oncorhynchus mykiss). Treatment with proline significantly reduced voluntary food intake at 2 h and 3 h after oral administration, while glutamic acid showed a less pronounced satiating effect at 3 h. The mRNA expression of taste receptor subunits tas1r1, tas1r2a, tas1r2b and tas1r3 was measured in the epithelium overlying the bony basihyal of the fish (analogous to the tetrapod tongue) at 10, 20 or 30 min following treatment. No significant changes were observed, except for a tas1r down-regulation by valine at 30 min. Of the downstream taste signalling genes that were analysed in parallel, plcb2 and possibly trpm5 (non-significant trend) were down-regulated 20 min after proline and glutamic acid treatment. The signal originated in the oropharyngeal and/or gastric cavity presumably relays to the brain as changes in genes involved in the regulation of food intake occurred in hypothalamus 10–30 min after oral treatment with amino acids. In particular, proline induced changes consistent with an increased anorexigenic potential in the hypothalamus. We have therefore demonstrated, for the first time in fish, that the peripheral (pre-absorptive) detection of an amino acid (l-proline), presumably by taste-related mechanisms, elicits a satiety signal that in hypothalamus is translated into changes in cellular signalling and neuropeptides regulating food intake, ultimately resulting in decreased food intake.

2005 ◽  
Vol 3 (2) ◽  
pp. 97-101
Author(s):  
Q. Niu ◽  
P. Niu ◽  
Q. Zhang ◽  
L. Wang ◽  
S. He ◽  
...  

Aluminum exposure has been reported to be related to learning and memory impairment. This study examines the role of aluminum in alterating amino acids of the cerebral cortex of rats. The Step-down type tests were performed to investigate the alteration of learning and memory of rats induced by aluminum. The amino acids in the cerebral cortex were detected by high performance liquid chromatography (HLPC). Results show that the amounts of aluminum in the cerebral cortex increased by 5.0mgAl3+/(Kg·BW) group and 10.0mg Al3+/(Kg·BW) group. In the Step-down type test, the EN1 increased significantly in the Al3+ 10.0mg/(Kg·BW) group. The latency shortened obviously and the EN2 increased significantly in the 10.0mg Al3+/(Kg·BW) group. The content of Glu (Glutamic acid) increased but the content of GABA (gamma-aminobutyric acid) decreased significantly in the 10.0mg Al3+/(Kg·BW) group. This present study shows evidence that the disorder of amino acid neurotransmitters system plays an important role in the impairment of learning and memory of rats induced by aluminum.


1981 ◽  
Vol 111 (9) ◽  
pp. 1568-1579 ◽  
Author(s):  
Joan E. Deady ◽  
Bruce Anderson ◽  
Joseph A. O'Donnell ◽  
James G. Morris ◽  
Quinton R. Rogers

mBio ◽  
2018 ◽  
Vol 9 (2) ◽  
pp. e00528-18 ◽  
Author(s):  
Richard C. White ◽  
Felizza F. Gunderson ◽  
Jessica Y. Tyson ◽  
Katherine H. Richardson ◽  
Theo J. Portlock ◽  
...  

ABSTRACTLegionella pneumophilagenes encoding LapA, LapB, and PlaC were identified as the most highly upregulated type II secretion (T2S) genes during infection ofAcanthamoeba castellanii, although these genes had been considered dispensable on the basis of the behavior of mutants lacking eitherlapAandlapBorplaC. AplaCmutant showed even higher levels oflapAandlapBtranscripts, and alapA lapBmutant showed heightening ofplaCmRNA levels, suggesting that the role of the LapA/B aminopeptidase is compensatory with respect to that of the PlaC acyltransferase. Hence, we made double mutants and found thatlapA plaCmutants have an ~50-fold defect during infection ofA. castellanii. These data revealed, for the first time, the importance of LapA in any sort of infection; thus, we purified LapA and defined its crystal structure, activation by another T2S-dependent protease (ProA), and broad substrate specificity. When the amoebal infection medium was supplemented with amino acids, the defect of thelapA plaCmutant was reversed, implying that LapA generates amino acids for nutrition. Since the LapA and PlaC data did not fully explain the role of T2S in infection, we identified, via proteomic analysis, a novel secreted protein (NttD) that promotes infection ofA. castellanii. AlapA plaC nttDmutant displayed an even greater (100-fold) defect, demonstrating that the LapA, PlaC, and NttD data explain, to a significant degree, the importance of T2S. LapA-, PlaC-, and NttD-like proteins had distinct distribution patterns within and outside theLegionellagenus. LapA was notable for having as its closest homologue anA. castellaniiprotein.IMPORTANCETransmission ofL. pneumophilato humans is facilitated by its ability to grow inAcanthamoebaspecies. We previously documented that type II secretion (T2S) promotesL. pneumophilainfection ofA. castellanii. Utilizing transcriptional analysis and proteomics, double and triple mutants, and crystal structures, we defined three secreted substrates/effectors that largely clarify the role of T2S during infection ofA. castellanii. Particularly interesting are the unique functional overlap between an acyltransferase (PlaC) and aminopeptidase (LapA), the broad substrate specificity and eukaryotic-protein-like character of LapA, and the novelty of NttD. Linking LapA to amino acid acquisition, we defined, for the first time, the importance of secreted aminopeptidases in intracellular infection. Bioinformatic investigation, not previously applied to T2S, revealed that effectors originate from diverse sources and distribute within theLegionellagenus in unique ways. The results of this study represent a major advance in understandingLegionellaecology and pathogenesis, bacterial secretion, and the evolution of intracellular parasitism.


1994 ◽  
Vol 72 (8) ◽  
pp. 841-848 ◽  
Author(s):  
G. Harvey Anderson ◽  
Shuqin Luo ◽  
Leonidas Trigazis ◽  
Greta Kubis ◽  
Edmund T. S. Li

This study examined the effects of selected groups of essential amino acids (EAAs), given by gavage, on short-term food and water intake. Amino acid groups were selected on the basis of their common physiologic functions in relation to current hypotheses on the role of amino acids in food intake control, and the quantities given were based on the proportions in 1.5 g of the EAA content of albumin. The complete EAA mixture (1.5 g) suppressed food intake by an average of 60 and 37% during the 1st and 2nd h of feeding, respectively, but had no influence on feeding in the subsequent 12 h. Total daily (14 h) intake was decreased by 9%. With the exception of the aromatic amino acid (Phe + Tyr + Trp, 0.34 g) group, all groups significantly decreased food intake by a comparable magnitude (32%) during the 1st h. In this time period, rats given the EAAs, Arg + Met + Val (0.38 g), and Arg + His + Lys (0.44 g) mixtures increased their water intake, whereas intake by rats given the Phe + Tyr + Trp + Thr (0.46 g) and Ile + Leu + Val (0.45 g) mixtures was unchanged. Thus, the food intake suppression caused by EAAs was not accounted for by an equal effect of its component amino acid groups. As well, food intake suppression by amino acid groups was not explained by increased water consumption, nor was it simply related to the quantity of nitrogen provided by the treatment.Key words: food intake, water intake, essential amino acids.


Development ◽  
1999 ◽  
Vol 126 (23) ◽  
pp. 5275-5284
Author(s):  
I. Zinke ◽  
C. Kirchner ◽  
L.C. Chao ◽  
M.T. Tetzlaff ◽  
M.J. Pankratz

We have isolated a Drosophila mutant, named pumpless, which is defective in food intake and growth at the larval stage. pumpless larvae can initially feed normally upon hatching. However, during late first instar stage, they fail to pump the food from the pharynx into the esophagus and concurrently begin moving away from the food source. Although pumpless larvae do not feed, they do not show the typical physiologic response of starving animals, such as upregulating genes involved in gluconeogenesis or lipid breakdown. The pumpless gene is expressed specifically in the fat body and encodes a protein with homology to a vertebrate enzyme involved in glycine catabolism. Feeding wild-type larvae high levels of amino acids could phenocopy the feeding and growth defects of pumpless mutants. Our data suggest the existence of an amino acid-dependent signal arising from the fat body that induces cessation of feeding in the larva. This signaling system may also mediate growth transition from larval to the pupal stage during Drosophila development.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3958-3958
Author(s):  
Bahram Alamdary Badlou ◽  
Gerit Spierenburg ◽  
Hans Ulricht ◽  
Hans Deckmyn ◽  
W. Martin Smid ◽  
...  

Abstract Platelet storage at 04 C suppresses bacterial multiplication, but induces clusters of glycoprotein (GP) Ibalpha that trigger their phagocytosis by macrophages and reduce their survival after transfusion. We searched for a method that detects cold-induced changes in GPIbalpha involved in phagocytosis. STUDY DESIGN AND METHODS: Human platelets were isolated and stored for up to 48 hrs at 0C. Binding of a PE-labeled antibody directed against amino acids 1–35 on GPIbalpha (AN51-PE) was compared with phagocytosis of platelets by matured monocytic THP-1 cells, analyzed by FACS. RESULTS: Freshly isolated platelets were detected as a single population of AN51-PE positive particles and showed < 5% phagocytosis. Cold storage led to a decrease in AN51-PE binding and an increase in phagocytosis. N-acetylglucosamine (GlcNAc), known to interfere with macrophage recognition of GPIbalpha clusters, restored normal AN51-PE binding to cold-stored platelets and suppressed phagocytosis. CONCLUSIONS: We conclude that binding of an antibody against AA 1–35 on GPIbalpha reflects changes in GPIbalpha that make platelets targets for phagocytosis by macrophages.


2017 ◽  
Vol 59 (4) ◽  
pp. 377-390 ◽  
Author(s):  
Cristina Velasco ◽  
Cristina Otero-Rodiño ◽  
Sara Comesaña ◽  
Jesús M Míguez ◽  
José L Soengas

We assessed in rainbow trout hypothalamus the effects of oleate and octanoate on levels and phosphorylation status of two transcription factors, FoxO1 and CREB, possibly involved in linking activation of fatty acid sensing with modulation of food intake through the expression of brain neuropeptides. Moreover, we assessed changes in the phosphorylation status of three proteins possibly involved in modulation of these transcription factors such as Akt, AMPK and mTOR. In a first experiment, we evaluated, in pools of hypothalamus incubated for 3 h and 6 h at 15°C in a modified Hanks’ medium containing 100 or 500 µM oleate or octanoate, the response of fatty acid sensing, neuropeptide expression and phosphorylation status of proteins of interest. The activation of fatty acid sensing and enhanced anorectic potential occurred in parallel with the activation of Akt and mTOR, and the inhibition of AMPK. The changes in these proteins would relate to a neuropeptide expression through changes in the phosphorylation status of transcription factors under their control, such as CREB and FoxO1, which displayed inhibitory (CREB) or activatory (FoxO1) responses when tissues were incubated with oleate or octanoate. In a second experiment, we incubated hypothalamus for 6 h with 500 µM oleate or octanoate alone or in the presence of specific inhibitors of Akt, AMPK, mTOR, CREB or FoxO1. The presence of inhibitors counteracted the effects of oleate or octanoate on the phosphorylation status of the proteins of interest. The results support, for the first time in fish, the involvement of these proteins in the regulation of food intake by fatty acids.


1997 ◽  
Vol 78 (2) ◽  
pp. 293-300 ◽  
Author(s):  
Fabio Favilli ◽  
Patrizia Marraccini ◽  
Teresa Iantomasi ◽  
Maria T. Vincenzini

The present study reports data on absorption of orally administered glutathione (GSH) in rat jejunum and in other organs, and the possible role of specific transport systems of GSH and γ-glutamyltranspeptidase (EC 2.3.2.1; γ-GT) activity. GSH levels were measured simultaneously in various organs after oral GSH administration to untreated rats and rats treated with L-buthionine sulfoximine (BSO) or acivicin (AT125). BSO selectively inhibits GSH intracellular synthesis and AT125 is a specific inhibitor of γ-GT activity. GSH levels were also measured after oral administration of an equivalent amount of the constituent amino acids of GSH to untreated and BSO-treated rats. Significant increases in GSH levels were found in jejunum, lung, heart, liver and brain after oral GSH administration to untreated rats. GSH increases were also obtained in all organs, except liver, when GSH was administered to rats previously GHS-depleted by treatment with BSO. The analysis of all results allowed us to distinguish between the increase in GSH intracellular levels due to intact GSH uptake by specific transporters, and that due to GSH degradation by γ-GT activity and subsequent absorption of degradation products with intracellular resynthesis of GSH; both these mechanisms seemed to be involved in increasing GSH content in heart after oral GSH administration. Jejunum, lung and brain took up GSH mostly intact, by specific transport systems, while in liver GSH uptake occurred only by its breakdown by γ-GT activity followed by intracellular resynthesis.


OSEANA ◽  
2018 ◽  
Vol 43 (3) ◽  
pp. 52-60
Author(s):  
Diah Anggraini Wulandari

THE BENEFITS AND ROLE OF SQUID FOR HEALTH. Squids are rich in protein with a protein content 15-20%. Squids containing macro and micro minerals such as sodium, potassium, phosphorus, calcium, magnesium and selenium, besides that squid also comprise essential amino acids such as tryptophan, threonine, methionine, lysine, leucine, isoleucine, valine, phenylalanine, and non-essential amino acids such as glutamic acid, aspartic acid, tyrosine, cysteine, serine, proline, glycine, arginine and histidine. Squid ink contain alkaloids that potential as anti-inflammatory, antihypertensive, anti-diabetic, anti-microbial and anti-malaria agents. The benefit of Squids in the food industry are an enhancer of flavor and an artificial leather constituent in the biomedical field.


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