Influence of ammonia concentration on [15N]ammonia uptake andde novosynthesis of different amino acids by mixed rumen microorganisms from the sheep rumenin vitro

1999 ◽  
Vol 1999 ◽  
pp. 212-212 ◽  
Author(s):  
C. Atasoglu ◽  
C.J. Newbold ◽  
R.J. Wallace
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
De Novo ◽  
Ammonia Concentration ◽  
Dependent Manner ◽  
Microbial Protein ◽  
Concentration Dependent Manner ◽  
Rumen Microorganisms ◽  
Ammonia Uptake

Ammonia is thought to be the main source of nitrogen for protein synthesis by the rumen microorganisms, but peptides and amino acids derived from protein degradation are also incorporated into microbial protein. Recent experiments carried out by Atasogluet al.(1998) demonstrated that preformed amino acids decrease the uptake of ammonia into microbial protein and microbial amino acids in a concentration-dependent manner. However, little is known about how rumen ammonia concentrations affect ammonia uptake into microbial protein. The present study was undertaken to determine the influence of rumen ammonia concentrations on ammonia incorporation andde novosynthesis of individual amino acids by the mixed rumen microorganismsin vitro.

Influence of the concentration of peptides on [15N]ammonia incorporation and de novo synthesis of different amino acids by mixed microorganisms from the sheep rumen in vitro

1998 ◽  
Vol 1998 ◽  
pp. 175-175
Author(s):  
C. Atasoglu ◽  
N.D. Walker ◽  
C.J. Newbold ◽  
R.J. Wallace
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
De Novo ◽  
De Novo Synthesis ◽  
Rumen Microorganisms ◽  
Microbial Nitrogen ◽  
Sheep Rumen

Ammonia plays an important role in providing N for protein synthesis by rumen microorganisms. Studies using [15N]ammonia or [15N]urea indicate that the proportion of microbial nitrogen derived from ammonia is highly variable, ranging from 18 to 100% (Nolan, 1975; Salter et al., 1979). Peptides and amino acids are also incorporated by rumen microorganisms. They generally stimulate growth (Argyle & Baldwin, 1989), but little is known about the factors which govern the relative proportions of microbial amino acids which are derived from pre-formed amino acids and from ammonia. The present study was undertaken to determine how the concentration of peptides affects ammonia incorporation and the de novo synthesis of individual amino acids by mixed rumen microorganisms.

Influence of the concentration of peptides on [15N]ammonia incorporation and de novo synthesis of different amino acids by mixed microorganisms from the sheep rumen in vitro

1998 ◽  
Vol 1998 ◽  
pp. 175-175
Author(s):  
C. Atasoglu ◽  
N.D. Walker ◽  
C.J. Newbold ◽  
R.J. Wallace
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
De Novo ◽  
De Novo Synthesis ◽  
Rumen Microorganisms ◽  
Microbial Nitrogen ◽  
Sheep Rumen

Ammonia plays an important role in providing N for protein synthesis by rumen microorganisms. Studies using [15N]ammonia or [15N]urea indicate that the proportion of microbial nitrogen derived from ammonia is highly variable, ranging from 18 to 100% (Nolan, 1975; Salter et al., 1979). Peptides and amino acids are also incorporated by rumen microorganisms. They generally stimulate growth (Argyle & Baldwin, 1989), but little is known about the factors which govern the relative proportions of microbial amino acids which are derived from pre-formed amino acids and from ammonia. The present study was undertaken to determine how the concentration of peptides affects ammonia incorporation and the de novo synthesis of individual amino acids by mixed rumen microorganisms.

scholarly journals Action of growth hormone in vitro on the net uptake and incorporation into protein of amino acids in muscle from intact rabbits given protein-deficient diets

1976 ◽  
Vol 35 (1) ◽  
pp. 1-10 ◽  
Author(s):  
M. R. Turner ◽  
P. J. Reeds ◽  
K. A. Munday
Keyword(s):  
Amino Acids ◽  
Growth Hormone ◽  
Protein Synthesis ◽  
Amino Acid ◽  
De Novo ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Amino Acid Incorporation ◽  
Acid Incorporation

1. Net amino acid uptake, and incorporation into protein have been measured in vitro in the presence and absence of porcine growth hormone (GH) in muscle from intact rabbits fed for 5 d on low-protein (LP), protein-free (PF) or control diets.2. In muscle from control and LP animals GH had no effect on the net amino acid uptake but stimulated amino acid incorporation into protein, although this response was less in LP animals than in control animals.3. In muscle from PF animals, GH stimulated both amino acid incorporation into protein and the net amino acid uptake, a type of response which also occurs in hypophysectomized animals. The magnitude of the effect of GH on the incorporation of amino acids into protein was reduced in muscle from PF animals.4. The effect of GH on the net amino acid uptake in PF animals was completely blocked by cycloheximide; the uptake effect of GH in these animals was dependent therefore on de novo protein synthesis.5. It is proposed that in the adult the role of growth hormone in protein metabolism is to sustain cellular protein synthesis when there is a decrease in the level of substrate amino acids, similar to that which occurs during a short-term fast or when the dietary protein intake is inadequate.

scholarly journals Signal transduction for chemotaxis and haptotaxis by matrix molecules in tumor cells.

1990 ◽  
Vol 110 (4) ◽  
pp. 1427-1438 ◽  
Author(s):  
S Aznavoorian ◽  
M L Stracke ◽  
H Krutzsch ◽  
E Schiffmann ◽  
L A Liotta
Keyword(s):  
Protein Synthesis ◽  
Matrix Protein ◽  
Type Iv Collagen ◽  
De Novo ◽  
Protein Synthesis Inhibitor ◽  
Dependent Manner ◽  
Recognition Sequence ◽  
Synthesis Inhibitor ◽  
Concentration Dependent Manner ◽  
Type Iv

Transduction of signals initiating motility by extracellular matrix (ECM) molecules differed depending on the type of matrix molecule and whether the ligand was in solution or bound to a substratum. Laminin, fibronectin, and type IV collagen stimulated both chemotaxis and haptotaxis of the A2058 human melanoma cell line. Peak chemotactic responses were reached at 50-200 nM for laminin, 50-100 nM for fibronectin, and 200-370 nM for type IV collagen. Checkerboard analysis of each attractant in solution demonstrated a predominantly directional (chemotactic) response, with a minor chemokinetic component. The cells also migrated in a concentration-dependent manner to insoluble step gradients of substratum-bound attractant (haptotaxis). The haptotactic responses reached maximal levels at coating concentrations of 20 nM for laminin and type IV collagen, and from 30 to 45 nM for fibronectin. Pretreatment of cells with the protein synthesis inhibitor, cycloheximide (5 micrograms/ml), resulted in a 5-30% inhibition of both chemotactic and haptotactic responses to each matrix protein, indicating that de novo protein synthesis was not required for a significant motility response. Pretreatment of cells with 50-500 micrograms/ml of synthetic peptides containing the fibronectin cell-recognition sequence GRGDS resulted in a concentration-dependent inhibition of fibronectin-mediated chemotaxis and haptotaxis (70-80% inhibition compared to control motility); negative control peptide GRGES had only a minimal effect. Neither GRGDS nor GRGES significantly inhibited motility to laminin or type IV collagen. Therefore, these results support a role for the RGD-directed integrin receptor in both types of motility response to fibronectin. After pretreatment with pertussis toxin (PT), chemotactic responses to laminin, fibronectin, and type IV collagen were distinctly different. Chemotaxis to laminin was intermediate in sensitivity; chemotaxis to fibronectin was completely insensitive; and chemotaxis to type IV collagen was profoundly inhibited by PT. In marked contrast to the inhibition of chemotaxis, the hepatotactic responses to all three ligands were unaffected by any of the tested concentrations of PT. High concentrations of cholera toxin (CT; 10 micrograms/ml) or the cAMP analogue, 8-Br-cAMP (0.5 mM), did not significantly affect chemotactic or haptotactic motility to any of the attractant proteins, ruling out the involvement of cAMP in the biochemical pathway initiating motility in these cells. The sensitivity of chemotaxis induced by laminin and type IV collagen, but not fibronectin, to PT indicates the involvement of a PT-sensitive G protein in transduction of the signals initiating motility to soluble laminin and type IV collagen.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Responsiveness of human neutrophils to interleukin-4: induction of cytoskeletal rearrangements, de novo protein synthesis and delay of apoptosis

1997 ◽  
Vol 325 (1) ◽  
pp. 147-153 ◽  
Author(s):  
Denis GIRARD ◽  
Robert PAQUIN ◽  
André D. BEAULIEUL
Keyword(s):  
Protein Synthesis ◽  
De Novo ◽  
Biological Activities ◽  
Interleukin 4 ◽  
Human Neutrophils ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Cytoskeletal Rearrangements ◽  
First Time ◽  
De Novo Protein Synthesis

Interleukin-4 (IL-4) and IL-13 are cytokines that share many biological activities. We have previously demonstrated that IL-13 affects a number of neutrophil responses, and here we extend our observations to IL-4. We present, for the first time, direct evidence for the presence of functional IL-4 receptors on human neutrophils. We report that IL-4 induces RNA synthesis in a concentration-dependent manner and, based on observations of the induction of morphological cell shape changes and spreading onto glass, we demonstrate that IL-4 activates neutrophil cytoskeletal rearrangements. We further show that IL-4 is a potent activator of de novo protein synthesis in neutrophils, and we identify by microsequencing one of these proteins as the cytoskeletal protein actin. We were also able to demonstrate for the first time that actin is cleaved into at least two fragments of ∼ 30 kDa (pI 5.4) and ∼ 25 kDa (pI 5.0) in neutrophils. Finally, we report that IL-4 delays neutrophil apoptosis, as assessed by morphological observations from cytocentrifuge preparations, as well as by measurement of differences in staining by flow cytometry with both propidium iodide and Hoechst reagent. Taken together, we conclude that IL-4 is a more potent neutrophil agonist than previously believed. We discuss the possibility that the induction of the de novo synthesis of actin by IL-4 is related to the mechanism by which this cytokine delays apoptosis; in addition, the cleavage of this protein is likely to contribute to the apoptotic process.

scholarly journals Effect of urea coating by chitosan on the dynamics of ammonia concentration and rumen fermentation in vitro

2022 ◽  
Vol 951 (1) ◽  
pp. 012004
Author(s):  
S Nayohan ◽  
K G Wiryawan ◽  
A Jayanegara
Keyword(s):  
Protein Synthesis ◽  
Organic Matter ◽  
Dry Matter ◽  
Block Design ◽  
Ammonia Concentration ◽  
Rumen Fermentation ◽  
Microbial Protein ◽  
Microbial Protein Synthesis ◽  
Randomized Complete Block Design

Abstract The aim of this study was to determine the effect of coating urea by chitosan at graded levels on ammonia concentration and rumen fermentation in vitro. This study used Factorial Randomized Complete Block Design (RCBD) to test ammonia parameter and Randomized Complete Block Design (RCBD) for pH, microbial protein synthesis, dry matter and organic matter digestibility, and Volatile Fatty Acid (VFA). The treatments tested were: P0 = addition non coating urea 1%; P1 = coating urea by chitosan 1%; P2 = coating urea by chitosan 2%; P3 = coating urea by chitosan 3%. The data obtained were analysed by using ANOVA and continued with Tukey HSD test with SPSS version 25. The results of this study showed that the coating of urea chitosan had no significant effect on pH, dry matter and organic matter digestibility, microbial protein synthesis, and amonia concentration in the rumen. However, it significantly reduced (P <0.05) total VFA concentration. It can be concluded that the application of urea coating by chitosan does not affect on the degradation of urea in the rumen.

scholarly journals Effects of rumen-degradable-to-undegradable protein ratio in ruminant diet on in vitro digestibility, rumen fermentation, and microbial protein synthesis

2021 ◽  
Vol 14 (3) ◽  
pp. 640-648
Author(s):  
Ezi Masdia Putri ◽  
Mardiati Zain ◽  
Lili Warly ◽  
Hermon Hermon
Keyword(s):  
Protein Synthesis ◽  
Dietary Protein ◽  
Crude Protein ◽  
Ammonia Concentration ◽  
Nutrient Digestibility ◽  
Pennisetum Purpureum ◽  
In Vitro Digestibility ◽  
Microbial Protein ◽  
Microbial Protein Synthesis

Background and Aim: Feeding ruminants must notice the degradability of feed, especially protein. Microbial rumen requires ammonia from rumen degradable protein (RDP) beside that ruminant require bypass protein or rumen undegradable protein (RUP) and microbial crude protein. The aim of the study was to discover the best RDP:RUP ratio in beef cattle diets commonly used by Indonesian farmers using an in vitro methodology. Materials and Methods: Samples of Pennisetum purpureum, Leucaena leucocephala, Indigofera zollingeriana, cassava, maize, palm kernel cake, rice bran, and tofu waste were formulated into dietary treatments (dry matter [DM] basis). All experiments were carried out using a 3×3×2 factorial, randomized block design with three replications. Treatments consisted of three protein levels (12%, 14%, and 16%), two energy levels (65% and 70%), and three RDP:RUP ratio levels (55:45, 60:40, and 65:35). The experimental diets were incubated in vitro using buffered rumen fluid for 48 h at 39°C. After incubation, the supernatants were analyzed to determine pH, ammonia concentration, total volatile fatty acid (VFA), and microbial protein synthesis. The residues were analyzed to determine DM, organic matter, protein, and RUP digestibility. Results: Increased protein, energy, and RDP levels increased digestibility, ammonia concentrations, total VFAs, and microbial protein synthesis (p<0.05), while rations with 16% protein lowered these parameters (p<0.05). Conclusion: Increased dietary protein (from 12% to 14% DM), energy (from 65% to 70% DM), and RDP (from 55% to 65% crude protein [CP]) levels increased nutrient digestibility, ammonia concentration, total VFA levels, and microbial protein synthesis. The diet containing 14% DM dietary protein and 70% DM energy, which contained 55%, 60%, or 65% CP RDP optimally increased nutrient digestibility, ammonia concentration, total VFA levels, and microbial protein synthesis. Thus, feed based on these RDP:RUP ratios can optimize ruminant productivity.

scholarly journals 1,25(OH)2D3 stimulates Mg2+uptake into MDCT cells: modulation by extracellular Ca2+and Mg2+

2001 ◽  
Vol 280 (5) ◽  
pp. F868-F878 ◽  
Author(s):  
Gordon Ritchie ◽  
Dirk Kerstan ◽  
Long-Jun Dai ◽  
Hyung Sub Kang ◽  
Lucie Canaff ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
De Novo ◽  
Divalent Cations ◽  
Gene Activation ◽  
Peptide Hormone ◽  
Distal Convoluted Tubule ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Dihydroxyvitamin D ◽  
Magnesium Uptake

The distal convoluted tubule plays a significant role in renal magnesium conservation. Although the cells of the distal convoluted tubule possess the vitamin D receptor, little is known about the effects of 1α,25-dihydroxyvitamin D [1,25(OH)2D3] on magnesium transport. In this study, we examined the effect of 1,25(OH)2D3 on distal cellular magnesium uptake and the modulation of this response by extracellular Ca2+and Mg2+ in an immortalized mouse distal convoluted tubule (MDCT) cell line. MDCT cells possess the divalent cation-sensing receptor (CaSR) that responds to elevation of extracellular Ca2+ and Mg2+ concentrations to diminish peptide hormone-stimulated Mg2+ uptake. Mg2+uptake rates were determined by microfluorescence in Mg2+-depleted MDCT cells. Treatment of MDCT cells with 1,25(OH)2D3 for 16–24 h stimulated basal Mg2+ uptake in a concentration-dependent manner from basal levels of 164 ± 5 to 210 ± 11 nM/s, representing a 28 ± 3% change. Pretreatment with actinomycin D or cycloheximide abolished 1,25(OH)2D3-stimulated.Mg2+uptake (154 ± 18 nM/s), suggesting that 1,25(OH)2D3 stimulates Mg2+ uptake through gene activation and protein synthesis. Elevation of extracellular Ca2+ inhibited 1,25(OH)2D3-stimulated Mg2+ uptake (143 ± 5 nM/s). Preincubation of the cells with an antibody to the CaSR prevented the inhibition by elevated extracellular Ca2+ of 1,25(OH)2D3-stimulated Mg2+ uptake (202 ± 8 nM/s). Treatment with an antisense CaSR mRNA oligodeoxynucleotide also abolished the effects of extracellular Ca2+ on 1,25(OH)2D3-responsive Mg2+ entry. This showed that elevated extracellular calcium modulates 1,25(OH)2D-mediated responses through the CaSR. In summary, 1,25(OH)2D3 stimulated Mg2+ uptake in MDCT cells, and this is dependent on de novo protein synthesis. Elevation of extracellular Ca2+, acting via the CaSR, inhibited 1,25(OH)2D3-stimulated Mg2+ entry. These data indicate that 1,25(OH)2D3 has important effects on the control of magnesium entry in MDCT cells and these responses can be modulated by extracellular divalent cations.

scholarly journals Potential of Prebiotic D-Tagatose for Prevention of Oral Disease

2021 ◽  
Vol 11 ◽  
Author(s):  
Shota Mayumi ◽  
Masae Kuboniwa ◽  
Akito Sakanaka ◽  
Ei Hashino ◽  
Asuka Ishikawa ◽  
...  
Keyword(s):  
Amino Acids ◽  
Bacterial Species ◽  
Viable Cell ◽  
Oral Disease ◽  
Dependent Manner ◽  
Oral Streptococci ◽  
Concentration Dependent Manner ◽  
Carbohydrate Source ◽  
Dental Biofilm

Recent studies have shown phenotypic and metabolic heterogeneity in related species including Streptococcus oralis, a typical oral commensal bacterium, Streptococcus mutans, a cariogenic bacterium, and Streptococcus gordonii, which functions as an accessory pathogen in periodontopathic biofilm. In this study, metabolites characteristically contained in the saliva of individuals with good oral hygiene were determined, after which the effects of an identified prebiotic candidate, D-tagatose, on phenotype, gene expression, and metabolic profiles of those three key bacterial species were investigated. Examinations of the saliva metabolome of 18 systemically healthy volunteers identified salivary D-tagatose as associated with lower dental biofilm abundance in the oral cavity (Spearman’s correlation coefficient; r = -0.603, p = 0.008), then the effects of D-tagatose on oral streptococci were analyzed in vitro. In chemically defined medium (CDM) containing D-tagatose as the sole carbohydrate source, S. mutans and S. gordonii each showed negligible biofilm formation, whereas significant biofilms were formed in cultures of S. oralis. Furthermore, even in the presence of glucose, S. mutans and S. gordonii showed growth suppression and decreases in the final viable cell count in a D-tagatose concentration-dependent manner. In contrast, no inhibitory effects of D-tagatose on the growth of S. oralis were observed. To investigate species-specific inhibition by D-tagatose, the metabolomic profiles of D-tagatose-treated S. mutans, S. gordonii, and S. oralis cells were examined. The intracellular amounts of pyruvate-derived amino acids in S. mutans and S. gordonii, but not in S. oralis, such as branched-chain amino acids and alanine, tended to decrease in the presence of D-tagatose. This phenomenon indicates that D-tagatose inhibits growth of those bacteria by affecting glycolysis and its downstream metabolism. In conclusion, the present study provides evidence that D-tagatose is abundant in saliva of individuals with good oral health. Additionally, experimental results demonstrated that D-tagatose selectively inhibits growth of the oral pathogens S. mutans and S. gordonii. In contrast, the oral commensal S. oralis seemed to be negligibly affected, thus highlighting the potential of administration of D-tagatose as an oral prebiotic for its ability to manipulate the metabolism of those targeted oral streptococci.

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