Phosphonates: Their Natural Occurrence and Physiological Role

2020 ◽  
Author(s):  
Paweł Kafarski
Keyword(s):  
Physiological Role ◽  
Natural Occurrence

scholarly journals 5-Hydroxytryptophan (5-HTP): Natural Occurrence, Analysis, Biosynthesis, Biotechnology, Physiology and Toxicology

2020 ◽  
Vol 22 (1) ◽  
pp. 181
Author(s):  
Massimo E. Maffei
Keyword(s):  
Animal Studies ◽  
Tryptophan Hydroxylase ◽  
Metabolic Diseases ◽  
Physiological Role ◽  
Molecular Engineering ◽  
Natural Occurrence ◽  
Treatment Of Depression ◽  
Analysis And Synthesis ◽  
Natural Component

L-5-hydroxytryptophan (5-HTP) is both a drug and a natural component of some dietary supplements. 5-HTP is produced from tryptophan by tryptophan hydroxylase (TPH), which is present in two isoforms (TPH1 and TPH2). Decarboxylation of 5-HTP yields serotonin (5-hydroxytryptamine, 5-HT) that is further transformed to melatonin (N-acetyl-5-methoxytryptamine). 5-HTP plays a major role both in neurologic and metabolic diseases and its synthesis from tryptophan represents the limiting step in serotonin and melatonin biosynthesis. In this review, after an look at the main natural sources of 5-HTP, the chemical analysis and synthesis, biosynthesis and microbial production of 5-HTP by molecular engineering will be described. The physiological effects of 5-HTP are discussed in both animal studies and human clinical trials. The physiological role of 5-HTP in the treatment of depression, anxiety, panic, sleep disorders, obesity, myoclonus and serotonin syndrome are also discussed. 5-HTP toxicity and the occurrence of toxic impurities present in tryptophan and 5-HTP preparations are also discussed.

scholarly journals Natural occurrence and physiological role of a truncated eIF4E in the porcine endometrium during implantation

2010 ◽  
Vol 432 (2) ◽  
pp. 353-363 ◽  
Author(s):  
Karin Wollenhaupt ◽  
Kati Reinke ◽  
Klaus-Peter Brüssow ◽  
Dirk Albrecht ◽  
Ute Tiemann ◽  
...  
Keyword(s):  
Binding Protein ◽  
Physiological Role ◽  
Northern Blotting ◽  
Initiation Factor ◽  
Regulation Mechanism ◽  
Natural Occurrence ◽  
Translational Initiation ◽  
Free Translation

The present study is the first report providing evidence for a physiological role of a truncated form of the mRNA cap-binding protein eIF4E1 (eukaryotic initiation factor 4E1). Our initial observation was that eIF4E, which mediates the mRNA cap function by recruiting the eIF4F complex (composed of eIF4E, 4G and 4A), occurs in two forms in porcine endometrial tissue in a strictly temporally restricted fashion. The ubiquitous prototypical 25 kDa form of eIF4E was found in ovariectomized and cyclic animals. A new stable 23 kDa variant, however, is predominant during early pregnancy at the time of implantation. Northern blotting, cDNA sequence analysis, in vitro protease assays and MS showed that the 23 kDa form does not belong to a new class of eIF4E proteins. It represents a proteolytically processed variant of eIF4E1, lacking not more than 21 amino acids at the N-terminus. Steroid replacements indicated that progesterone in combination with 17β-oestradiol induced the formation of the 23 kDa eIF4E. Modified cell-free translation systems mimicking the situation in the endometrium revealed that, besides eIF4E, eIF4G was also truncated, but not eIF4A or PABP [poly(A)-binding protein]. The 23 kDa form of eIF4E reduced the repressive function of 4E-BP1 (eIF4E-binding protein 1) and the truncated eIF4G lacked the PABP-binding site. Thus we suggest that the truncated eIF4E provides an alternative regulation mechanism by an altered dynamic of eIF4E/4E-BP1 binding under conditions where 4E-BP1 is hypophosphorylated. Together with the impaired eIF4G–PABP interaction, the modified translational initiation might particularly regulate protein synthesis during conceptus attachment at the time of implantation.

The growth of mica polytypes as studied by conventional and high-resolution TEM

1983 ◽  
Vol 41 ◽  
pp. 174-177
Author(s):  
A. Baronnet ◽  
M. Amouric
Keyword(s):  
Water Pressure ◽  
Point Of View ◽  
Temperature Fields ◽  
Natural Occurrence ◽  
Growth Mechanisms ◽  
Long Period ◽  
High Resolution Tem ◽  
Layer Stacking ◽  
Experimental Works ◽  
Potential Use

The origin of mica polytypes has long been a challenging problem for crystal- lographers, mineralogists and petrologists. From the petrological point of view, interest in this field arose from the potential use of layer stacking data to furnish further informations about equilibrium and/or kinetic conditions prevailing during the crystallization of the widespread mica-bearing rocks. From the compilation of previous experimental works dealing with the occurrence domains of the various mica "polymorphs" (1Mr, 1M, 2M1, 2M2 and 3T) within water-pressure vs temperature fields, it became clear that most of these modifications should be considered as metastable for a fixed mica species. Furthermore, the natural occurrence of long-period (or complex) polytypes could not be accounted for by phase considerations. This highlighted the need of a more detailed kinetic approach of the problem and, in particular, of the role growth mechanisms of basal faces could play in this crystallographic phenomenon.

Detection and mapping of interactions between chromatin and the nuclear envelope in drosophila embryos

1995 ◽  
Vol 53 ◽  
pp. 764-765
Author(s):  
W.F. Marshall ◽  
A.F. Dernburg ◽  
B. Harmon ◽  
J.W. Sedat
Keyword(s):  
Nuclear Envelope ◽  
Chromatin Condensation ◽  
Three Dimensional ◽  
Physiological Role ◽  
Nuclear Surface ◽  
Intact Cells ◽  
Molecular Determinants ◽  
Surface Harmonic ◽  
Drosophila Embryos

Interactions between chromatin and nuclear envelope (NE) have been implicated in chromatin condensation, gene regulation, nuclear reassembly, and organization of chromosomes within the nucleus. To further investigate the physiological role played by such interactions, it will be necessary to determine which loci specifically interact with the nuclear envelope. This will not only facilitate identification of the molecular determinants of this interaction, but will also allow manipulation of the pattern of chromatin-NE interactions to probe possible functions. We have developed a microscopic approach to detect and map chromatin-NE interactions inside intact cells.Fluorescence in situ hybridization (FISH) is used to localize specific chromosomal regions within the nucleus of Drosophila embryos and anti-lamin immunofluorescence is used to detect the nuclear envelope. Widefield deconvolution microscopy is then used to obtain a three-dimensional image of the sample (Fig. 1). The nuclear surface is represented by a surface-harmonic expansion (Fig 2). A statistical test for association of the FISH spot with the surface is then performed.

Effect of prolactin inhibition under heat exposure on water intake and excretion of urine, sodium and potassium in bulls

1980 ◽  
Vol 94 (3) ◽  
pp. 315-320 ◽  
Author(s):  
D. Schams ◽  
E. Stephan ◽  
R. D. Hooley
Keyword(s):  
Water Intake ◽  
Heat Exposure ◽  
Physiological Role ◽  
Treated Group ◽  
Serum Prolactin ◽  
Control Value ◽  
Light Regimen ◽  
Group I ◽  
Urinary Potassium ◽  
Group Ii

Abstract. Six Holstein bulls were housed in a climate-chamber under constant light regimen and after two weeks of preconditioning at 15°C, 60% relative humidity RH (day) and 12°C, 60% RH (night) were subjected to two weeks of heat exposure. This involved one week at 30°C and 60% RH (day) and 25°C and 60% RH (night) and a further week at 35°C, 60% RH (day) and 30°C, 60% RH (night). Three bulls were untreated (group I) and 3 bulls were treated (group II) just before and during heat exposure with a prolactin inhibitor to study the possible physiological role of prolactin on the regulation of water, potassium and sodium. Serum prolactin levels increased significantly (P < 0.01) in group I from the control value of 6 ng/ml to 33 and 44 ng/ml when the ambient temperature was increased (weeks 3 and 4) and then decreased to 21 and 12 ng/ml after reduction in temperature during weeks 5 and 6, respectively. For group II prolactin values decreased under the treatment with the prolactin inhibitor to 0.5 ng/ml and remained at this level throughout the experiment. GH levels were unaffected by heat treatment or by treatment with prolactin inhibitor. There were no differences between groups I and II in respiratory rate, pulse rate and rectal temperature. Water intake increased in both groups under heat exposure but decreased significantly afterwards only in group II. Differences in urinary excretion volume and blood serum osmolality were not significant. Urinary potassium and sodium excretion were unchanged in group II but increased with heat exposure in group I. During heat exposure 2 bulls of group II lost weight despite maintaining food intake.

Physiological role for Angptl4/fiaf in exercise-induced muscle AMPK activation

2013 ◽  
Author(s):  
Min-Seon Kim ◽  
Ghi-Su Kim ◽  
Hyuckki Chang ◽  
Mi-Seon Shin ◽  
Hyun Kyong Kim
Keyword(s):  
Physiological Role ◽  
Ampk Activation ◽  
Exercise Induced

Determination of natural radionuclides in waste generated in the potable water treatment plants of the Zona da Mata of the state of Pernambuco- Brazil

2019 ◽  
Vol 7 (2A) ◽  
Author(s):  
Adriana Muniz De Almeida Albuquerque
Keyword(s):  
Water Treatment ◽  
Potable Water ◽  
Natural Radionuclides ◽  
The United States ◽  
Radioactive Material ◽  
Human Consumption ◽  
Radiological Protection ◽  
Natural Occurrence ◽  
Water Treatment Plants ◽  
Potable Water Treatment

The water purification procedure aims to obtain a product appropriate for human consumption, minimizing the presence of contaminants and toxic substances present in the water. Among these contaminants, some radionuclides of natural origin, such as uranium, thorium and their descendants, have been identified. Studies have shown that the stages of purification are quite effective in removing the radionuclides contained in water. The removal is due to co-precipitation of the radionuclides with the suspended materials and the precipitated material is accumulated and characterized as a Technologically Concentrated Natural Occurrence Radioactive Material (TENORM) by the United States Environmental Protection Agency (USEPA). This residue can present significant levels of radioactivity and, when discarded in the environment without any treatment, can generate a problem of environmental impact and a risk to the health of the population. In this way, some gamma emitters of the series of U, Th and the K-40 were determined in the residues generated at the Potable Water Treatment Plants – PWTPs in six municipalities of Pernambuco. The results obtain corroborate the classification of the residues generated in the PWTPs as concentrators of the radioactive components contained in the water supplied to the system and reinforce the need for the release to the environment, which is the usual way of disposal of this waste, to be carried out only after considering the radiological protection standards established.

1824-P: Leptin Receptor Neurons in the Hypothalamic Ventromedial Nucleus Play a Physiological Role in Regulating Glucose Tolerance

Diabetes ◽  
2019 ◽  
Vol 68 (Supplement 1) ◽  
pp. 1824-P
Author(s):  
CHELSEA L. FABER ◽  
TRISTA J. HARVEY ◽  
KEVIN R. VELASCO ◽  
VINCENT DAMIAN ◽  
MICHAEL W. SCHWARTZ ◽  
...  
Keyword(s):  
Glucose Tolerance ◽  
Leptin Receptor ◽  
Physiological Role ◽  
Ventromedial Nucleus ◽  
Receptor Neurons

Enteral enhancement of glucose disposition by both insulin-dependent and insulin-independent processes. A physiological role of glucagon-like peptide I

Diabetes ◽  
1995 ◽  
Vol 44 (12) ◽  
pp. 1433-1437 ◽  
Author(s):  
D. A. D'Alessio ◽  
R. L. Prigeon ◽  
J. W. Ensinck
Keyword(s):  
Physiological Role ◽  
Insulin Dependent ◽  
Glucagon Like Peptide
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