scholarly journals Factors affecting de novo synthesis of amino acids by mixed microorganisms from the sheep rumen in vitro and by pure cultures of rumen bacteria

1997 ◽  
Vol 37 (Suppl. 1) ◽  
pp. 62-63
Author(s):  
C. Atasoglu ◽  
C. Valdés ◽  
ND Walker ◽  
CJ Newbold ◽  
RJ Wallace
Keyword(s):  
Amino Acids ◽  
De Novo ◽  
Rumen Bacteria ◽  
De Novo Synthesis ◽  
Factors Affecting ◽  
Pure Cultures ◽  
Sheep Rumen

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 An enzymatic activation of formaldehyde for nucleotide methylation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Charles Bou-Nader ◽  
Frederick W. Stull ◽  
Ludovic Pecqueur ◽  
Philippe Simon ◽  
Vincent Guérineau ◽  
...  
Keyword(s):  
Amino Acids ◽  
Thymidylate Synthase ◽  
Active Site ◽  
De Novo ◽  
Crystallographic Structure ◽  
De Novo Synthesis ◽  
Active Site Residues ◽  
Enzymatic Activation ◽  
Enzyme Cofactors ◽  
Unique Ability

AbstractFolate enzyme cofactors and their derivatives have the unique ability to provide a single carbon unit at different oxidation levels for the de novo synthesis of amino-acids, purines, or thymidylate, an essential DNA nucleotide. How these cofactors mediate methylene transfer is not fully settled yet, particularly with regard to how the methylene is transferred to the methylene acceptor. Here, we uncovered that the bacterial thymidylate synthase ThyX, which relies on both folate and flavin for activity, can also use a formaldehyde-shunt to directly synthesize thymidylate. Combining biochemical, spectroscopic and anaerobic crystallographic analyses, we showed that formaldehyde reacts with the reduced flavin coenzyme to form a carbinolamine intermediate used by ThyX for dUMP methylation. The crystallographic structure of this intermediate reveals how ThyX activates formaldehyde and uses it, with the assistance of active site residues, to methylate dUMP. Our results reveal that carbinolamine species promote methylene transfer and suggest that the use of a CH2O-shunt may be relevant in several other important folate-dependent reactions.

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 De Novo Synthesis of Amino Acids by the Ruminal Bacteria Prevotella bryantii B14,Selenomonas ruminantium HD4, and Streptococcus bovis ES1

1998 ◽  
Vol 64 (8) ◽  
pp. 2836-2843 ◽  
Author(s):  
Cengiz Atasoglu ◽  
Carmen Valdés ◽  
Nicola D. Walker ◽  
C. James Newbold ◽  
R. John Wallace
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
De Novo ◽  
Dependent Manner ◽  
Streptococcus Bovis ◽  
De Novo Synthesis ◽  
Ruminal Bacteria ◽  
Total N ◽  
Selenomonas Ruminantium ◽  
Prevotella Bryantii

ABSTRACT The influence of peptides and amino acids on ammonia assimilation and de novo synthesis of amino acids by three predominant noncellulolytic species of ruminal bacteria, Prevotella bryantii B14, Selenomonas ruminantiumHD4, and Streptococcus bovis ES1, was determined by growing these bacteria in media containing 15NH4Cl and various additions of pancreatic hydrolysates of casein (peptides) or amino acids. The proportion of cell N and amino acids formed de novo decreased as the concentration of peptides increased. At high concentrations of peptides (10 and 30 g/liter), the incorporation of ammonia accounted for less than 0.16 of bacterial amino acid N and less than 0.30 of total N. At 1 g/liter, which is more similar to peptide concentrations found in the rumen, 0.68, 0.87, and 0.46 of bacterial amino acid N and 0.83, 0.89, and 0.64 of total N were derived from ammonia by P. bryantii, S. ruminantium, andS. bovis, respectively. Concentration-dependent responses were also obtained with amino acids. No individual amino acid was exhausted in any incubation medium. For cultures of P. bryantii, peptides were incorporated and stimulated growth more effectively than amino acids, while cultures of the other species showed no preference for peptides or amino acids. Apparent growth yields increased by between 8 and 57%, depending on the species, when 1 g of peptides or amino acids per liter was added to the medium. Proline synthesis was greatly decreased when peptides or amino acids were added to the medium, while glutamate and aspartate were enriched to a greater extent than other amino acids under all conditions. Thus, the proportion of bacterial protein formed de novo in noncellulolytic ruminal bacteria varies according to species and the form and identity of the amino acid and in a concentration-dependent manner.

Bioactive Alkaloids from the Tropical Marine Sponge Axinella carteri

1995 ◽  
Vol 50 (9-10) ◽  
pp. 669-674 ◽  
Author(s):  
A. Supriyono ◽  
B. Schwarz ◽  
V. Wray ◽  
L. Witte ◽  
W. E. G. Müller ◽  
...  
Keyword(s):  
Marine Sponge ◽  
Insecticidal Activity ◽  
De Novo ◽  
The Philippines ◽  
De Novo Synthesis ◽  
Mouse Lymphoma Cells ◽  
Guanidine Alkaloids ◽  
Neonate Larvae ◽  
Mouse Lymphoma

Abstract Analysis of the tropical marine sponge Axinella carteri afforded six unusual alkaloids, including the new brominated guanidine derivative 3-bromo-hymenialdisine. The structure elucidation of the new alkaloid is described. The alkaloid patterns of sponges collected in Indonesia or in the Philippines were shown to be qualitatively identical suggesting de novo synthesis by the sponge or by endosymbiontic microorganisms rather than uptake by filterfeeding. All alkaloids were screened for insecticidal activity as well as for cytotoxicity. The guanidine alkaloids hymenialdisine and debromohymenialdisine exhibited insecticidal activity towards neonate larvae of the polyphagous pest insect Spodoptera littoralis (LD50s of 88 and 125 ppm, respectively), when incorporated into artificial diet and offered to the larvae in a chronic feeding bioassay. The remaining alkaloids, including the new compound, were inactive in this bioassay. Cytotoxicity was studied in vitro using L5178y mouse lymphoma cells. Debromohymenialdisine was again the most active compound (ED50 1.8 μg/ml) followed by hymenialdisine and 3-bromohymenialdisine, which were essentially equitoxic and exhibited ED50s of 3.9 μg/ml in both cases. The remaining alkaloids were inactive against this cell line

Immunology: Evidence for the in-vitro de-novo synthesis of immunoglobulin and a previously undescribed 17 kDa protein (TEP-2) by the mucosa of the Fallopian tube

1993 ◽  
Vol 8 (8) ◽  
pp. 1199-1202 ◽  
Author(s):  
S.D. Maguiness ◽  
K. Shrimanker ◽  
O. Djahanbakhch ◽  
B. Teisner ◽  
J.G. Grudzinskas
Keyword(s):  
Fallopian Tube ◽  
De Novo ◽  
De Novo Synthesis

A de novo Synthesis of Oxindoles from Cyclohexanone-Derived γ-Keto-ester Acceptors Using a Desaturative Amination–Cyclization Approach

Synthesis ◽  
2021 ◽  
Author(s):  
Henry P. Caldora ◽  
Sebastian Govaerts ◽  
Shashikant U. Dighe ◽  
Oliver J. Turner ◽  
Daniele Leonori
Keyword(s):  
Amino Acids ◽  
Primary Amine ◽  
De Novo ◽  
Building Blocks ◽  
De Novo Synthesis ◽  
Keto Ester ◽  
Mild Conditions ◽  
Blockbuster Drug

Here we report a desaturative approach for oxindole synthesis. This method uses simple γ-ester-containing cyclohexanones and primary amine building blocks as coupling partners. A dual photoredox–cobalt manifold is used to generate a secondary aniline that, upon heating, cyclizes with the pendent ester functionality. The process operates under mild conditions and was applied to the modification of several amino acids, the blockbuster drug mexiletine, as well as the formation of dihydroquinolinones.

scholarly journals Inhibiting Methanogenesis Stimulated de novo Synthesis of Microbial Amino Acids in Mixed Rumen Batch Cultures Growing on Starch but not on Cellulose

2020 ◽  
Vol 8 (6) ◽  
pp. 799
Author(s):  
Emilio M. Ungerfeld ◽  
M. Fernanda Aedo ◽  
Camila Muñoz ◽  
Natalie L. Urrutia ◽  
Emilio D. Martínez ◽  
...  
Keyword(s):  
Amino Acids ◽  
De Novo ◽  
Nitrogen Sources ◽  
Environmental Benefits ◽  
De Novo Synthesis ◽  
Protein Nitrogen ◽  
Protein Supplements ◽  
Batch Cultures ◽  
Sufficient Energy ◽  
Ruminant Diets

Ameliorating methane (CH4) emissions from ruminants would have environmental benefits, but it is necessary to redirect metabolic hydrogen ([H]) toward useful sinks to also benefit animal productivity. We hypothesized that inhibiting rumen methanogenesis would increase de novo synthesis of microbial amino acids (AA) as an alternative [H] sink if sufficient energy and carbon are provided. We examined the effects of inhibiting methanogenesis with 9, 10-anthraquione (AQ) on mixed rumen batch cultures growing on cellulose or starch as sources of energy and carbon contrasting in fermentability, with ammonium (NH4+) or trypticase (Try) as nitrogen (N) sources. Inhibiting methanogenesis with AQ inhibited digestion with cellulose but not with starch, and decreased propionate and increased butyrate molar percentages with both substrates. Inhibiting methanogenesis with 9, 10-anthraquinone increased de novo synthesis of microbial AA with starch but not with cellulose. The decrease in the recovery of [H] caused by the inhibition of methanogenesis was more moderate with starch due to an enhancement of butyrate and AA as [H] sinks. There may be an opportunity to simultaneously decrease the emissions of CH4 and N with some ruminant diets and replace plant protein supplements with less expensive non-protein nitrogen sources such as urea.

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