scholarly journals Relation between in vitro and in vivo assessment of amino acid availability

1989 ◽  
Vol 29 (4) ◽  
pp. 495-507 ◽  
Author(s):  
I. Galibois ◽  
L. Savoie ◽  
C. Simoes Nunes ◽  
A. Rérat
Keyword(s):  
Amino Acid ◽  
Amino Acid Availability ◽  
In Vivo Assessment

scholarly journals The Sko1p Repressor and Gcn4p Activator Antagonistically Modulate Stress-Regulated Transcription inSaccharomyces cerevisiae

2001 ◽  
Vol 21 (1) ◽  
pp. 16-25 ◽  
Author(s):  
Amparo Pascual-Ahuir ◽  
Ramón Serrano ◽  
Markus Proft
Keyword(s):  
Amino Acid ◽  
Specific Binding ◽  
Ion Homeostasis ◽  
Normal Growth ◽  
Yeast Cells ◽  
Target Sequence ◽  
Acid Uptake ◽  
Amino Acid Availability

ABSTRACT In the transcriptional response of Saccharomyces cerevisiae to stress, both activators and repressors are implicated. Here we demonstrate that the ion homeostasis determinant,HAL1, is regulated by two antagonistically operating bZIP transcription factors, the Sko1p repressor and the Gcn4p activator. A single CRE-like sequence (CRE HAL1 ) at position −222 to −215 with the palindromic core sequence TTACGTAA is essential for stress-induced expression of HAL1. Down-regulation of HAL1 under normal growth conditions requires specific binding of Sko1p to CRE HAL1 and the corepressor gene SSN6. Release from this repression depends on the function of the high-osmolarity glycerol pathway. The Gcn4p transcriptional activator binds in vitro to the same CRE HAL1 and is necessary for up-regulatedHAL1 expression in vivo, indicating a dual control mechanism by a repressor-activator pair occupying the same promoter target sequence. gcn4 mutants display a strong sensitivity to elevated K+ or Na+ concentrations in the growth medium. In addition to reduced HAL1 expression, this sensitivity is explained by the fact that amino acid uptake is drastically impaired by high Na+ and K+concentrations in wild-type yeast cells. The reduced amino acid biosynthesis of gcn4 mutants would result in amino acid deprivation. Together with the induction of HAL1 by amino acid starvation, these results suggest that salt stress and amino acid availability are physiologically interconnected.

scholarly journals Amino acid availability in poultry—in vitro and in vivo measurements

1999 ◽  
Vol 50 (5) ◽  
pp. 889 ◽  
Author(s):  
V. Ravindran ◽  
Wayne L. Bryden
Keyword(s):  
Amino Acid ◽  
Protein Quality ◽  
Poultry Feed ◽  
In Vitro Assays ◽  
Total Amino Acid ◽  
Amino Acid Availability ◽  
Amino Acid Contents ◽  
In Vivo Growth

Methodology to evaluate the protein quality or amino acid availability in feed ingredients for poultry using in vitro (enzymic, chemical, or microbiological assays), indirect in vivo (plasma amino acid assays), or direct in vivo (growth or digestibility assays) measurements has been reviewed. The specific applications and limitations of these methods are examined. In vitro assays are useful in providing information on heat damage in selected protein sources under defined conditions, and on relative ranking of different samples, but they cannot form the basis of practical feed formulations. While growth assays remain the only direct means of confirming nutritional relevance of values obtained by other procedures, in vivo digestibility assays appear to be most useful, at present, to estimate amino acid availability. Amino acid digestibility assays in poultry should be based on the analysis of digesta from the terminal ileum rather than excreta, because of the variable and modifying effects of hindgut microflora. Techniques used to estimate endogenous amino acid losses in poultry are discussed. The needs for correction of endogenous losses in amino acid digestibility calculations and the relative merits of apparent and true digestible amino acid systems are still being debated. It is, however, clear that both digestible amino systems are superior to the total amino acid system currently employed to formulate practical diets. Digestible amino acid values are likely to form the basis of poultry feed formulations in the future. In particular, there is an urgent need for more precise information on the variation in digestible amino acid contents of locally grown ingredients and on the factors causing this variation (e.g. variety, location, season, agronomic practices, processing, etc.).

Oxytocin analogues with non-coded amino acid residues in position 8: [8-Neopentylglycine]oxytocin and [8-cycloleucine]oxytocin

1987 ◽  
Vol 52 (9) ◽  
pp. 2317-2325 ◽  
Author(s):  
Jan Hlaváček ◽  
Jan Pospíšek ◽  
Jiřina Slaninová ◽  
Walter Y. Chan ◽  
Victor J. Hruby
Keyword(s):  
Amino Acid ◽  
Solid Phase Synthesis ◽  
Solid Phase ◽  
The Other ◽  
Amino Acid Residues ◽  
Phase Synthesis ◽  
Other Hand ◽  
Fragment Condensation

[8-Neopentylglycine]oxytocin (II) and [8-cycloleucine]oxytocin (III) were prepared by a combination of solid-phase synthesis and fragment condensation. Both analogues exhibited decreased uterotonic potency in vitro, each being about 15-30% that of oxytocin. Analogue II also displayed similarly decreased uterotonic potency in vivo and galactogogic potency. On the other hand, analogue III exhibited almost the same potency as oxytocin in the uterotonic assay in vivo and in the galactogogic assay.

Synthesis of Fragments of the Vasoactive Intestinal Peptide (VIP) and Analysis of Their Residual Biological Activities

1995 ◽  
Vol 60 (7) ◽  
pp. 1229-1235 ◽  
Author(s):  
Ivana Zoulíková ◽  
Ivan Svoboda ◽  
Jiří Velek ◽  
Václav Kašička ◽  
Jiřina Slaninová ◽  
...  
Keyword(s):  
Amino Acid ◽  
Biological Activities ◽  
Residual Activity ◽  
Detailed Examination ◽  
Amino Acid Residues ◽  
Linear Peptide ◽  
Zone Electrophoresis ◽  
Capillary Zone

The vasoactive intestinal (poly)peptide (VIP) is a linear peptide containing 28 amino acid residues, whose primary structure indicates a low metabolic stability. The following VIP fragments, as potential metabolites, and their analogues were prepared by synthesis on a solid: [His(Dnp)1]VIP(1-10), VIP(11-14), [D-Arg12]VIP(11-14), [Lys(Pac)15,21,Arg20]VIP(15-22), and VIP(23-28). After purification, the peptides were characterized by amino acid analysis, mass spectrometry, RP HPLC, and capillary zone electrophoresis. In some tests, detailed examination of the biological activity of the substances in vivo and in vitro gave evidence of a low, residual activity of some fragments, viz. a depressoric activity in vivo for [His(Dnp)1]VIP(1-10) and a stimulating activity for the release of α-amylase in vitro and in vivo for [Lys(Pac)15,21,Arg20]VIP(15-22) and VIP(23-28).

scholarly journals In vivo assessment of a single adenine mutation in 5′UTR of Endothelin-1 gene in paediatric cases with severe pulmonary hypertension: an observational study

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Abhishek Kumar ◽  
Minati Choudhury ◽  
Sakshi Dhingra Batra ◽  
Kriti Sikri ◽  
Anushree Gupta
Keyword(s):  
Pulmonary Hypertension ◽  
Congenital Heart ◽  
Small Sample Size ◽  
Small Sample ◽  
Severe Pulmonary Hypertension ◽  
Endothelin 1 ◽  
Circulating Levels ◽  
In Vivo Assessment

Abstract Objective Endothelin-1 plays an important role in the pathogenesis of severe pulmonary hypertension. The + 139 ‘A’, adenine insertion variant in 5′UTR of edn1 gene has been reported to be associated with increased expression of Endothelin-1 in vitro. The aim of present study was to explore the association of this variant with the circulating levels of Endothelin-1 in vivo using archived DNA and plasma samples from 38 paediatric congenital heart disease (cyanotic and acyanotic) patients with severe pulmonary hypertension. Results The plasma Endothelin-1 levels were highly varied ranging from 1.63 to75.16 pg/ml. The + 139 ‘A’ insertion variant in 5′UTR of edn1 was seen in 8 out of 38 cases with only one acyanotic sample demonstrating homozygosity of inserted ‘A’ allele at + 139 site (4A/4A genotype). The plasma Endothelin-1 levels in children with homozygous variant 3A/3A genotype were comparable in cyanotic and acyanotic groups. Lone 4A/4A acyanotic sample had ET-1 levels similar to the median value of ET-1 associated with 3A/3A genotype and was absent in cyanotic group presumably due to deleterious higher ET-1 levels. The discussed observations, limited by the small sample size, are suggestive of homozygous adenine insertion variant posing a risk in cyanotic babies with Severe Pulmonary Hypertension.

A novel polymorphism of human gene has an amino acid substitution (V365M) that decreases enzymatic activity in vitro and in vivo

2004 ◽  
Vol 76 (6) ◽  
pp. 519-527 ◽  
Author(s):  
T FUKAMI ◽  
M NAKAJIMA ◽  
R YOSHIDA ◽  
Y TSUCHIYA ◽  
Y FUJIKI ◽  
...  
Keyword(s):  
Amino Acid ◽  
Enzymatic Activity ◽  
Amino Acid Substitution ◽  
Human Gene

Reduced and S-carboxymethylated human growth hormone: a probe for diabetogenic action

1984 ◽  
Vol 247 (5) ◽  
pp. E639-E644
Author(s):  
C. M. Cameron ◽  
J. L. Kostyo ◽  
J. A. Rillema ◽  
S. E. Gennick
Keyword(s):  
Growth Hormone ◽  
Amino Acid ◽  
Human Growth Hormone ◽  
Human Growth ◽  
Mouse Mammary Gland ◽  
Amino Acid Incorporation ◽  
Acid Incorporation ◽  
Hypophysectomized Rats

The biological activity profile of reduced and S-carboxymethylated human growth hormone (RCM-hGH) was determined to establish its suitability for study of the diabetogenic property of hGH. RCM-hGH was found to have greatly attenuated in vivo growth-promoting activity in the 9-day weight-gain test in hypophysectomized rats (approximately 1%) and to have a similar low order of in vitro activity in stimulating amino acid incorporation into the protein of the isolated rat diaphragm. RCM-hGH also only had approximately 1% of the in vitro insulin-like activity of the native hormone on isolated adipose tissue from hypophysectomized rats. In contrast, RCM-hGH retained substantial in vivo diabetogenic activity in the ob/ob mouse, appearing to have approximately 50% of the activity of the native hormone. RCM-hGH was also found to retain significant, although attenuated (25%), in vitro lactogenic activity when tested for the ability to stimulate amino acid incorporation into a casein-rich protein fraction in mouse mammary gland explants. Because RCM-hGH exhibits a high degree of diabetogenic activity, although lacking significant anabolic or insulin-like activities, it will be useful as a "monovalent" probe for the study of the molecular mechanism of the diabetogenic action of GH.

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