scholarly journals Caseins as Regulators of Hematopoiesis

2020 ◽  
Author(s):  
Edgar Ledesma-Martinez ◽  
Vanihamin Domínguez-Meléndez ◽  
Itzen Aguiñiga-Sánchez ◽  
Edelmiro Santiago-Osorio
Keyword(s):  
Amino Acids ◽  
Biological Activities ◽  
Physiological Role ◽  
Antimicrobial Activities ◽  
Strong Immune Response ◽  
Physiological Importance ◽  
Immunosuppressed Patients ◽  
Main Protein ◽  
Over Time

The main physiological role of casein, the main protein component in the milk, is to be a source of amino acids that are required for the growth of the neonate; therefore, casein is considered a highly nutritious protein. Over time, it has been revealed that casein is a protein whose physiological importance reaches levels far superior to the food field, having a wide array of biological activities including antimicrobial activities, facilitating absorption of nutrients, as well as acting as a growth factor and an immune stimulant. Here we analyze how caseins can exert numerous hematopoietic and immunomodulatory actions, their role in granulopoiesis, monocytopoiesis, and lymphopoiesis from the early stages of postnatal development seemingly throughout life, and we wonder if casein could be useful to fight pathogens resistant to antibiotics, inducing a strong immune response in immunosuppressed patients, or even be a prophylactic strategy to prevent infections.

Development of sensitivity to cAMP-inducing hormones in the rat stomach

1984 ◽  
Vol 247 (3) ◽  
pp. G231-G239
Author(s):  
C. Gespach ◽  
Y. Cherel ◽  
G. Rosselin
Keyword(s):  
Biological Activities ◽  
Physiological Role ◽  
H2 Receptor Antagonist ◽  
Adult Rats ◽  
Gastric Glands ◽  
Camp Generation ◽  
Final Maturation ◽  
Noncompetitive Inhibitor ◽  
Regulatory Properties

Development of cAMP responses to secretin, pancreatic glucagon, and histamine was measured in gastric glands of fetal (day 20), postnatal (days 1-30), and adult rats (day 65). cAMP stimulation by these hormones was already detected on day 20 of gestation. cAMP generation showed biphasic variations during the 1st days of life and at the onset of weaning (day 20). Anticipated weaning at day 14 triggered precocious maturation (efficacies) of the cAMP-generating systems sensitive to secretin, glucagon, and histamine without changing the potencies of the hormones. During development, the general characteristics (potency and pharmacological or regulatory properties) of the receptor-cAMP systems studied were comparable with those evidenced in adult rats. At days 5, 20, and 65, vasoactive intestinal peptide and the peptide having N-terminal histidine and C-terminal isoleucine amide (PHI) were about 100 times less potent than secretin (EC50 = 1.5 X 10(-9) M secretin). The histamine action could be blocked by the competitive H2-receptor antagonist cimetidine (70-100% inhibition) as well as by the noncompetitive inhibitor somatostatin (37-62% inhibition). The data indicate that these regulatory hormones (secretin, glucagon(s), histamine, and somatostatin) might have a direct effect on gastric glands and may modulate their biological activities (metabolism, differentiation, proliferation, and exocrine and endocrine secretions) from the neonatal period in rats. The important physiological role of weaning on the final maturation of the cAMP-generating systems in rat gastric glands is underlined.

scholarly journals The Glycine- and Proline-Rich Protein AtGPRP3 Negatively Regulates Plant Growth in Arabidopsis

2020 ◽  
Vol 21 (17) ◽  
pp. 6168
Author(s):  
Xiaojing Liu ◽  
Xin Wang ◽  
Xin Yan ◽  
Shaobo Li ◽  
Hui Peng
Keyword(s):  
Amino Acids ◽  
Plant Growth ◽  
Physiological Role ◽  
Short Peptides ◽  
Hydrophobic Domain ◽  
Gfp Fusion Protein ◽  
Repeat Domain ◽  
Arabidopsis Plant ◽  
Proline Rich Protein

Glycine- and proline-rich proteins (GPRPs) comprise a small conserved family that is widely distributed in the plant kingdom. GPRPs are relatively short peptides (<200 amino acids) that contain three typical domains, including an N-terminal XYPP-repeat domain, a middle hydrophobic domain rich in alanine, and a C-terminal HGK-repeat domain. These proteins have been proposed to play fundamental roles in plant growth and environmental adaptation, but their functions remain unknown. In this study, we selected an Arabidopsis GPRP (AtGPRP3) to profile the physiological role of GPRPs. Transcripts of AtGPRP3 could be detected in the whole Arabidopsis plant, but greater amounts were found in the rosette, followed by the cauline. The AtGPRP3::GFP fusion protein was mainly localized in the nucleus. The overexpression and knockout of AtGPRP3, respectively, retarded and accelerated the growth of Arabidopsis seedlings, while the increase in the growth rate of atgprp3 plants was offset by the complementary expression of AtGPRP3. CAT2 and CAT3, but not CAT1, interacted with AtGPRP3 in the nuclei of Arabidopsis protoplasts. The knockout of CAT2 by CRISPR-Cas9 retarded the growth of the Arabidopsis seedlings. Together, our data suggest that AtGPRP3 negatively regulates plant growth, potentially through CAT2 and CAT3.

scholarly journals Key role of l-alanine in the control of hepatic protein synthesis

1987 ◽  
Vol 241 (2) ◽  
pp. 491-498 ◽  
Author(s):  
D Pérez-Sala ◽  
R Parrilla ◽  
M S Ayuso
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Physiological Role ◽  
Chain Elongation ◽  
Liver Protein ◽  
Isolated Liver Cells ◽  
Metabolic Transformation ◽  
Hepatic Protein Synthesis

We investigated the effects of administration of single amino acids to starved rats on the regulation of protein synthesis in the liver. Of all the amino acids tested, only alanine, ornithine and proline promoted statistically significant increases in the extent of hepatic polyribosome aggregation. The most effective of these was alanine, whose effect of promoting polyribosomal aggregation was accompanied by a decrease in the polypeptide-chain elongation time. The following observations indicate that alanine plays an important physiological role in the regulation of hepatic protein synthesis. Alanine was the amino acid showing the largest decrease in hepatic content in the transition from high (fed) to low (starved) rates of protein synthesis. The administration of glucose or pyruvate is also effective in increasing liver protein synthesis in starved rats, and their effects were accompanied by an increased hepatic alanine content. An increase in hepatic ornithine content does not lead to an increased protein synthesis, unless it is accompanied by an increase of alanine. The effect of alanine is observed either in vivo, in rats pretreated with cycloserine to prevent its transamination, or in isolated liver cells under conditions in which its metabolic transformation is fully impeded.

scholarly journals Hemodialysis—Nutritional Flaws in Diagnosis and Prescriptions. Could Amino Acid Losses Be the Sharpest “Sword of Damocles”?

Nutrients ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1773 ◽  
Author(s):  
Piergiorgio Bolasco
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Hemodialysis Patients ◽  
Calorie Intake ◽  
Protein Energy Wasting ◽  
Slowing Down ◽  
Protein Energy ◽  
Determining Factor ◽  
Over Time

This review aims to highlight the strengths and weaknesses emerging from diagnostic evaluations and prescriptions in an intent to prevent progression over time of malnutrition and/or protein-energy wasting (PEW) in hemodialysis (HD) patients. In particular, indications of the most effective pathway to follow in diagnosing a state of malnutrition are provided based on a range of appropriate chemical-clinical, anthropometric and instrumental analyses and monitoring of the nutritional status of HD patients. Finally, based on the findings of recent studies, therapeutic options to be adopted for the purpose of preventing or slowing down malnutrition have been reviewed, with particular focus on protein-calorie intake, the role of oral and/or intravenous supplements and efficacy of some classes of amino acids. A new determining factor that may lead inexorably to PEW in hemodialysis patients is represented by severe amino acid loss during hemodialysis sessions, for which mandatory compensation should be introduced.

scholarly journals Role of D-aminoacyl-tRNA deacylase beyond chiral proofreading as a cellular defense against glycine mischarging by AlaRS

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Komal Ishwar Pawar ◽  
Katta Suma ◽  
Ayshwarya Seenivasan ◽  
Santosh Kumar Kuncha ◽  
Satya Brata Routh ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Active Site ◽  
Unknown Function ◽  
Physiological Importance ◽  
Cellular Defense

Strict L-chiral rejection through Gly-cisPro motif during chiral proofreading underlies the inability of D-aminoacyl-tRNA deacylase (DTD) to discriminate between D-amino acids and achiral glycine. The consequent Gly-tRNAGly ‘misediting paradox’ is resolved by EF-Tu in the cell. Here, we show that DTD’s active site architecture can efficiently edit mischarged Gly-tRNAAla species four orders of magnitude more efficiently than even AlaRS, the only ubiquitous cellular checkpoint known for clearing the error. Also, DTD knockout in AlaRS editing-defective background causes pronounced toxicity in Escherichia coli even at low-glycine levels which is alleviated by alanine supplementation. We further demonstrate that DTD positively selects the universally invariant tRNAAla-specific G3•U70. Moreover, DTD’s activity on non-cognate Gly-tRNAAla is conserved across all bacteria and eukaryotes, suggesting DTD’s key cellular role as a glycine deacylator. Our study thus reveals a hitherto unknown function of DTD in cracking the universal mechanistic dilemma encountered by AlaRS, and its physiological importance.

scholarly journals Fate of uptaken host proteins in Taenia solium and Taenia crassiceps cysticerci

2018 ◽  
Vol 38 (4) ◽  
Author(s):  
Jeanette Flores-Bautista ◽  
José Navarrete-Perea ◽  
Gladis Fragoso ◽  
Ana Flisser ◽  
Xavier Soberón ◽  
...  
Keyword(s):  
Amino Acids ◽  
Culture Medium ◽  
Taenia Solium ◽  
Physiological Role ◽  
Essential Amino Acids ◽  
Host Proteins ◽  
Taenia Crassiceps ◽  
The Matrix ◽  
Host Parasite

During the study of host–parasite relationships in taeniid parasite diseases, including cysticercosis and hydatidosis, reports have described the presence of host proteins in the cyst fluid and tissue of metacestodes. However, the fate or role of host elements inside the parasite remains barely explored. After the publication of genomes of four cestode species, it became clear that these organisms possess a limited biosynthetic capability. The initial goal of the present study was to determine if uptaken host proteins could be a source of essential amino acids for cysticerci. To track the utilization of uptaken proteins, we added metabolically labeled IgG-3H and GFP-3H to the culture medium of Taenia crassiceps cysticerci. Incorporation of labeled amino acid was evaluated by fluorography in cysticerci extracts. Our results showed that the use of uptaken proteins by cysticerci as a source of amino acids appeared negligible. Exploring alternative fates for the host proteins, proteomic analysis of the protein matrix in calcareous corpuscles was carried out. Since T. crassiceps does not contain calcareous corpuscles, proteomic analyses were performed in corpuscles of Taenia solium cysticerci. Our results demonstrated that host proteins represented approximately 70% of protein content in the calcareous corpuscles. The presence of the two major uptaken host proteins, namely albumin and IgG, was also demonstrated by Western blot in the matrix of corpuscles. Our findings strongly suggested that the uptake and disposal of host proteins involve calcareous corpuscles, expanding the physiological role of these mineral concretions to a far more important level than previously proposed.

scholarly journals Effect of pentagastrin and gastrin-17 on the secretory function of the gastric glands

2022 ◽  
pp. 75-78
Author(s):  
M. A. Zhuraeva ◽  
V. A. Aleynik ◽  
N. D. Ashuralieva ◽  
D. S. Kholikova
Keyword(s):  
Amino Acids ◽  
Physiological Role ◽  
The Body ◽  
Short Chain ◽  
Molecular Forms ◽  
Secretory Function ◽  
Gastric Glands ◽  
Digestive Glands

The regulation of the digestive glands of the stomach and pancreas in the body of animals and humans is provided by peptides, most of which are in various molecular forms. 10 molecular forms of peptides of the gastrin group and 5 peptides of the cholecystokinin (CCK) group have been identified, containing in their structure from 4 to 56 amino acids, the physiological role of which has been little studied. It has been proven that the liver removes up to 85% of short-chain peptides of the gastrin (pentagastrin) and cholecystokinin (CCK-8) groups.

scholarly journals Molecular and Physiological Role of the Trehalose-Hydrolyzing α-Glucosidase from Thermus thermophilus HB27

2008 ◽  
Vol 190 (7) ◽  
pp. 2298-2305 ◽  
Author(s):  
Susana Alarico ◽  
Milton S. da Costa ◽  
Nuno Empadinhas
Keyword(s):  
Amino Acids ◽  
Minimal Medium ◽  
Thermus Thermophilus ◽  
Physiological Role ◽  
Hydrolytic Activity ◽  
Recombinant Enzyme ◽  
New Feature ◽  
Hydrolysis Of ◽  
Reciprocal Replacement

ABSTRACT Trehalose supports the growth of Thermus thermophilus strain HB27, but the absence of obvious genes for the hydrolysis of this disaccharide in the genome led us to search for enzymes for such a purpose. We expressed a putative α-glucosidase gene (TTC0107), characterized the recombinant enzyme, and found that the preferred substrate was α,α-1,1-trehalose, a new feature among α-glucosidases. The enzyme could also hydrolyze the disaccharides kojibiose and sucrose (α-1,2 linkage), nigerose and turanose (α-1,3), leucrose (α-1,5), isomaltose and palatinose (α-1,6), and maltose (α-1,4) to a lesser extent. Trehalose was not, however, a substrate for the highly homologous α-glucosidase from T. thermophilus strain GK24. The reciprocal replacement of a peptide containing eight amino acids in the α-glucosidases from strains HB27 (LGEHNLPP) and GK24 (EPTAYHTL) reduced the ability of the former to hydrolyze trehalose and provided trehalose-hydrolytic activity to the latter, showing that LGEHNLPP is necessary for trehalose recognition. Furthermore, disruption of the α-glucosidase gene significantly affected the growth of T. thermophilus HB27 in minimal medium supplemented with trehalose, isomaltose, sucrose, or palatinose, to a lesser extent with maltose, but not with cellobiose (not a substrate for the α-glucosidase), indicating that the α-glucosidase is important for the assimilation of those four disaccharides but that it is also implicated in maltose catabolism.

Physiological role of d-amino acid-N-acetyltransferase of Saccharomyces cerevisiae: detoxification of d-amino acids

2005 ◽  
Vol 185 (1) ◽  
pp. 39-46 ◽  
Author(s):  
Geok-Yong Yow ◽  
Takuma Uo ◽  
Tohru Yoshimura ◽  
Nobuyoshi Esaki
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acids ◽  
Amino Acid ◽  
Physiological Role

scholarly journals Structural-based engineering expands the substrate scope of a cyclodipeptide synthase

2021 ◽  
Author(s):  
Emmajay Sutherland ◽  
Christopher Harding ◽  
Clarissa Czekster
Keyword(s):  
Crystal Structure ◽  
Amino Acids ◽  
Biological Activities ◽  
Substrate Selectivity ◽  
Cyclic Dipeptides ◽  
Successive Generations ◽  
The Way

Cyclodipeptide synthases (CDPSs) are a growing family of enzymes capable of producing a large variety of cyclodipetide products using aminoacylated tRNA. Histidine-containing cyclic dipeptides have important biological activities as anticancer and neuroprotective molecules. Out of the 120 experimentally validated CDPS members, only two are known to accept histidine as a substrate. Here, we studied the activities of both Para-CDPS from Parabacteroides sp. 20_3 and Parcu-CDPS from Parcubacteria bacterium RAAC4_OD1_1 which synthesise cyclo(His-Phe) and cyclo(His-Pro) respectively. Both enzymes accepted canonical and non-canonical amino acids as substrates to generate a library of novel molecules. In order to understand the substrate selectivity of these CDPSs, the crystal structure of Parcu-CDPS was solved (alongside a number of mutants) and the role of residues important for catalysis and histidine recognition were probed using mutagenesis. Three successive generations of mutants containing both single and double residue substitutions were generated leading to a change in substrate selectivity from histidine to phenylalanine and leucine. The research detailed herein is the first instance of successful engineering of a CDPS to yield different products, paving the way to direct the promiscuity of these enzymes to produce molecules of our choosing.

Sign in / Sign up

Export Citation Format

Share Document