Étude de quelques aspects du métabolisme carboné et azoté chez l'Arceuthobium oxycedri, gui nain du genévrier

1992 ◽  
Vol 70 (8) ◽  
pp. 1709-1716
Author(s):  
L. Rey ◽  
A. Sadik ◽  
A. Fer ◽  
S. Renaudin
Keyword(s):  
Amino Acids ◽  
Photosynthetic Activity ◽  
Nitrogen Nutrition ◽  
Nitrogen Supply ◽  
Dwarf Mistletoe ◽  
Gas Exchanges ◽  
Nitrogenous Compounds ◽  
Slow Development ◽  
Carbon Nutrition ◽  
Glutamate Oxalacetate Transaminase

In juniper dwarf mistletoe, Arceuthobium oxycedri (DC) M. Bieb., a hemiparasitic and epiphytic Angiosperm characterized by very reduced and slow development, the chlorophyll content of the shoots is relatively high for a parasitic plant. However, gas exchanges reveal a low net gain in carbon, and the real photosynthetic intensity is only about 1.5 to 2 times higher than the respiratory intensity in these organs. In the endophytic system, which is also chlorophyllous, a small amount of photosynthetic activity also occurs. By studying 14CO2 assimilation and carboxylase activities in both organs, it was possible to determine the ability of the parasite to satisfy part of its carbon requirements. Following the administration of 14CO2, radioactivity was mainly recovered in carbohydrates and to a lesser extent in organic acids and amino acids. This demonstrates that A. oxycedri has some autonomy for the fixation and distribution of carbon into various compounds. On the other hand, the parasite, since it is epiphytic, is completely dependent upon its host for nitrogen. The study of the activities of the key enzymes of nitrogen metabolism ([Formula: see text] and [Formula: see text] reductases, glutamine synthetase, glutamate dehydrogenase, glutamate-oxalacetate transaminase) shows that nitrogen supply from the host certainly occurs mainly in the form of reduced nitrogenous compounds (ammonia and (or) aminated organic compounds). The numerous labelled amino acids recovered after administration of 14CO2 show that A. oxycedri is able to redistribute the imported nitrogen in various ways. Key words: Arceuthobium oxycedri, parasitic Angiosperms, carbon nutrition, nitrogen nutrition.

Investigations on the root nodule bacteria of leguminous plants: XIX. Influence of various factors on the excretion of nitrogenous compounds from the nodules

1937 ◽  
Vol 27 (3) ◽  
pp. 332-348 ◽  
Author(s):  
Artturi Ilmari Virtanen ◽  
Synnöve von Hausen ◽  
Tauno Laine
Keyword(s):  
Amino Acids ◽  
Nitrogen Fixation ◽  
Root Nodule ◽  
Nitrogen Nutrition ◽  
Nitrogen Compounds ◽  
Nodule Bacteria ◽  
Fixed Nitrogen ◽  
Nitrogenous Compounds ◽  
Primary Products ◽  
Equal Effectiveness

1. It has been shown experimentally that the excretion of nitrogen noted by us in cultures of inoculated legumes takes place from the nodule bacteria, probably from the intranodular ones, and not from the roots. No excretion of amino acids occurs in cultures of uninoculated legumes growing on nitrate nitrogen.2. Our earlier hypothesis that the legumes receive their nitrogen nutrition from the nodules in the form of organic nitrogen compounds, particularly amino acids, is in perfect accord with our new observations concerning the process of excretion. All facts indicate that the amino acids concerned are primary products of the nitrogen fixation, and not breakdown products of proteins. Bond's valuable work along quite different lines produced results which support this conclusion. He, however, did not study the chemical nature of the nitrogen compounds in question.3. The excretion of nitrogen occurs in media capable of absorbing the excreted nitrogen compounds (cellulose, kaolin, sand, soil). The demonstration of the excretion is not possible in water cultures except when very large quantities of water are used. On the basis of these facts a hypothesis is advanced to explain the nature of the excretion.4. The term total fixed nitrogen has been used as an expression for the extent of nitrogen fixation, while the term extent of excretion is employed to indicate that percentage of the total fixed nitrogen which is excreted from the nodules.5. The extent of excretion depends largely on the strain used for inoculation. With strains of apparently equal effectiveness in nitrogen fixation, the extent of excretion may vary considerably, so that actually such strains differ in their effectiveness.

Gastrointestinal Interaction between Dietary Amino Acids and Gut Microbiota: With Special Emphasis on Host Nutrition

2020 ◽  
Vol 21 (8) ◽  
pp. 785-798 ◽  
Author(s):  
Abedin Abdallah ◽  
Evera Elemba ◽  
Qingzhen Zhong ◽  
Zewei Sun
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
Immune System ◽  
Gut Microbiota ◽  
Short Chain Fatty Acids ◽  
Nutrition And Health ◽  
Nitrogenous Compounds ◽  
Dietary Amino Acids ◽  
Host Nutrition ◽  
Chain Fatty Acids

The gastrointestinal tract (GIT) of humans and animals is host to a complex community of different microorganisms whose activities significantly influence host nutrition and health through enhanced metabolic capabilities, protection against pathogens, and regulation of the gastrointestinal development and immune system. New molecular technologies and concepts have revealed distinct interactions between the gut microbiota and dietary amino acids (AAs) especially in relation to AA metabolism and utilization in resident bacteria in the digestive tract, and these interactions may play significant roles in host nutrition and health as well as the efficiency of dietary AA supplementation. After the protein is digested and AAs and peptides are absorbed in the small intestine, significant levels of endogenous and exogenous nitrogenous compounds enter the large intestine through the ileocaecal junction. Once they move in the colonic lumen, these compounds are not markedly absorbed by the large intestinal mucosa, but undergo intense proteolysis by colonic microbiota leading to the release of peptides and AAs and result in the production of numerous bacterial metabolites such as ammonia, amines, short-chain fatty acids (SCFAs), branched-chain fatty acids (BCFAs), hydrogen sulfide, organic acids, and phenols. These metabolites influence various signaling pathways in epithelial cells, regulate the mucosal immune system in the host, and modulate gene expression of bacteria which results in the synthesis of enzymes associated with AA metabolism. This review aims to summarize the current literature relating to how the interactions between dietary amino acids and gut microbiota may promote host nutrition and health.

Effect of tiller age and time of nitrogen stress on seed production of Paspalum plicatulum

1973 ◽  
Vol 81 (2) ◽  
pp. 219-229 ◽  
Author(s):  
P. A. Chadhokar ◽  
L. R. Humphreys
Keyword(s):  
Ammonium Nitrate ◽  
Seed Size ◽  
Seed Yield ◽  
Growth And Development ◽  
Nitrogen Nutrition ◽  
Development Stage ◽  
Nitrogen Supply ◽  
Nitrogen Stress ◽  
Floral Initiation ◽  
Final Maturation

SummaryPaspalum plicatulum was grown at Brisbane in boxes of sand receiving basal nutrients and frequent irrigation; weekly levels of ammonium nitrate application were varied according to growth and development stage.The rate of tiller appearance increased to a maximum 40–50 days after sowing and almost ceased thereafter. Tiller leaf number, survival, fertility, inflorescence branching, seeds per raceme and seed size were positively related to tiller age. Young tillers were more sensitive to variations in nitrogen supply than old tillers.Adequate nitrogen nutrition during the vegetative phase from sowing to floral initiation (93 days) increased tiller and hence inflorescence density; increased inflorescence branching was compensated by fewer seeds per raceme. Good nitrogen nutrition during the phase from floral initiation to inflorescence exsertion (142 days) increased survival of late-formed tillers and hence inflorescence density; inflorescence branching, seeds per raceme and seed size were also increased. Nitrogen stress during the final maturation phase did not affect seed yield.

On the Nutrition and metabolism of zooplankton IV. The forms of nitrogen excreted By Calanus

1967 ◽  
Vol 47 (1) ◽  
pp. 113-120 ◽  
Author(s):  
E. D. S. Corner ◽  
B. S. Newell
Keyword(s):  
Amino Acids ◽  
Positive Reaction ◽  
Laboratory Experiments ◽  
Long Island Sound ◽  
Acartia Tonsa ◽  
Nitrogenous Compounds ◽  
Nitrogenous Substances ◽  
Experimental Density ◽  
Island Sound ◽  
Calanus Helgolandicus

A study has been made of the nitrogenous compounds excreted by Calanus helgolandicus (Claus) collected at Plymouth.Most of the excreted nitrogen is in the form of ammonia which accounts for 60–100% (average 74.3%) of the total, and some of the remainder may be lost as urea. There is no evidence for the excretion of measurable amounts of amino acids.Whether the animals are starved or fed they are primarily ammonotelic, and the quantity of ammonia produced at 10° C (3.33 μg/g. dry body wt/day) is not significantly changed when the animals are used at an abnormally high experimental density. This latter condition does, however, lead to the production of large quantities of additional nitrogenous substances that give a positive reaction with ninhydrin.IntroductionThe amounts of nitrogen excreted by zooplankton have been measured by several workers. Harris (1959) used the method of Riley (1953) to estimate the copious quantities of ammonia produced by animals (mainly Acartia tonsa and A. clausi) collected from Long Island Sound; Beers (1964), in laboratory experiments with the chaetognath Sagitta hispida, estimated the excreted ammonia by the procedure of Kruse & Mellon (1952); and Corner, Cowey & Marshall (1965) determined the ammonia excreted by Calanus helgolandicus and C. finmarchicus, using a ninhydrin technique described by Moore & Stein (1954). The methods employed by Harris and by Beers are specific for ammonia: that used by Corner et al. estimates nitrogenous substances (e.g. amino acids) in addition to ammonia, but certain tests were made which seemed to exclude the possibility that these substances contributed significantly to the nitrogen excreted by the animals.

THE OXIDATION OF ESTRONE-16-C14BY PEROXIDASE

1962 ◽  
Vol 40 (1) ◽  
pp. 459-469 ◽  
Author(s):  
P. H. Jellinck ◽  
Louise Irwin
Keyword(s):  
Amino Acids ◽  
Hydrogen Peroxide ◽  
Amino Acid ◽  
Serum Albumin ◽  
Oxidase Activity ◽  
Water Soluble ◽  
The Other ◽  
Aerobic Incubation ◽  
Nitrogenous Compounds ◽  
Initial Generation

Aerobic incubation of estrone-16-C14with peroxidase in the presence of serum albumin and other proteins resulted in the formation of water-soluble, ether-insoluble metabolites in high percentage yields. Similar products were formed when protein was replaced by cysteine or tryptophan but none of the other amino acids tested had any effect. The evidence points to an initial generation of hydrogen peroxide from these nitrogenous compounds by the enzyme acting as an aerobic oxidase, and the subsequent peroxidation of estrone to highly reactive products. These then combine with the protein or amino acid or else undergo alternative reactions. A strong chemical bond is formed with albumin and attempts to release the estrone metabolites from it were unsuccessful. Uterine homogenates from estrogen-treated rats showing high DPNH oxidase activity contained no "peroxidase" as measured by the formation of water-soluble products from estrone in the presence of protein.

Limits to Protein in Layer Diets Relative to Mitigating Ammonia Emission

2009 ◽  
Vol 2 (3) ◽  
pp. 143-150 ◽  
Author(s):  
Thomas Veens ◽  
Hwan Namkung ◽  
Steven Leeson
Keyword(s):  
Amino Acids ◽  
Feed Additives ◽  
Ammonia Emission ◽  
Minimal Amount ◽  
Ammonia Emissions ◽  
Microbial Conversion ◽  
Nitrogenous Compounds ◽  
Intact Proteins ◽  
Dietary Nitrogen ◽  
The Usa

Ammonia emissions from poultry farms currently contribute to air pollution and acid rain. There are no regulations in North America regarding emissions of ammonia although regulations are being drawn up in the USA and there is concern about the impacts of animal agricultural on the environment. Low crude protein (CP) diets can be an effective contributor to strategies of ammonia mitigation. Since virtually all ammonia originates from nitrogenous compounds in feed, then any attempt at ammonia mitigation must involve scrutiny of the levels of nitrogen, protein and amino acids (AA). Reducing dietary nitrogen/CP leads to reduced nitrogen in the excreta with less potential for microbial conversion to ammonia. Using low CP diets may be an economical strategy for ammonia emissions since the concept involves no special feed additives other than replacement AAs. Although AA requirements for layer hens are well known, the minimal amount of CP required is less clearly defined. AA requirements should be independent of diet CP, assuming there is adequate nitrogen for protein synthesis. However, the birds/ response in terms of reduced egg numbers and growth or change in egg composition, suggest that our estimates of amino acid supply are incorrect under these dietary regimes. Independent of bird age and AA supply, more problems are recorded when CP levels are <14-15%. It is timely to redefine the maintenance AA requirements of layers. Since the composition of eggs should give us direct estimates of needs for production, the only other unknown in formulating low CP diets is the efficiency of utilisation of free amino acids versus intact proteins.

THE INFLUENCE OF NITROGENOUS COMPOUNDS ON GROWTH OF PYTHIUM SPECIES

1967 ◽  
Vol 13 (11) ◽  
pp. 1509-1519 ◽  
Author(s):  
V. P. Agnihotri ◽  
O. Vaartaja
Keyword(s):  
Amino Acids ◽  
Organic Nitrogen ◽  
Aminobutyric Acid ◽  
Pythium Species ◽  
Surface Culture ◽  
Poor Growth ◽  
Nitrogenous Compounds ◽  
Chromatographic Techniques ◽  
Ammonium Compounds ◽  
N Compounds

The utilization of N compounds by P. ultimum Trow (strain I and II), P. rostratum Butler, and P. irregulare Buisman was examined in a chemically denned medium under controlled conditions in surface culture. All species were able to metabolize nitrate, ammonium, and organic nitrogen, and the amount of growth varied with the nitrogen source. In general, yeast extract, peptone, glycine, serine, histidine, cysteine, asparagine, aspartic acid, and glutamic acid supported favorable growth, whereas γ-aminobutyric acid, threonine, and alanine supported poor growth of these fungi. The addition of succinic acid at 0.02 M concentration to ammonium compounds further increased growth of four isolates.Preferential utilization of amino acids from a given mixture was recorded using paper chromatographic techniques. All four isolates gave more vegetative growth on mixtures of amino acids than when they were supplied singly.

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