scholarly journals Microbial amino acid synthesis and utilization in rats: incorporation of15N from15NH4Cl into lysine in the tissues of germ-free and conventional rats

1996 ◽  
Vol 76 (5) ◽  
pp. 689-700 ◽  
Author(s):  
David Torrallardona ◽  
C. Ian Harris ◽  
Marie E. Coates ◽  
Malcolm F. Fuller
Keyword(s):  
Isotope Ratio Mass Spectrometry ◽  
Acid Synthesis ◽  
Exchange Chromatography ◽  
The Body ◽  
Amino Acid Synthesis ◽  
Germ Free ◽  
N Enrichment ◽  
Fermentable Carbohydrates ◽  
Measurement Artifact ◽  
Protein Free Diet

The absorption of lysine synthesised by the gastrointestinal microflora was estimated by comparing the15N incorporated into body lysine in four germ-free (15N-GF) and four conventional (15N-CV) rats. They were fed for 10d on a protein-free diet containing fermentable carbohydrates and15NHM4Cl; another four conventional rats (control), fed on the same diet but with unlabelled NH4Cl, were used to estimate the natural abundance of15N. The eviscerated carcass of each rat was homogenized and a sample hydrolysed. Lysine was isolated by ion-exchange chromatography and its15N enrichment was measured by isotope-ratio mass spectrometry. The15N-CV rats significantly incorporated15N into their body lysine. The15N-GF rats had a statistically significant, although small, incorporation of15body lysine, probably arising from a measurement artifact. It was concluded, therefore, that all [15N]lysine was of microbial origin. The total lysine content in the body and the15N enrichment of lysine in the microbial fraction of the faeces of the15N-CV rats were also determined. The amount of microbial lysine absorbed by the15N-CV rats was estimated by dividing the total amount of [15N]lysine in the body by the enrichment of microbial lysine. It was estimated that the daily absorption of microbial lysine by the conventional rats was 21·3 (SE 2·04) mg/kg body weight0·75

scholarly journals Microbial amino acid synthesis and utilization in rats: the role of coprophagy

1996 ◽  
Vol 76 (5) ◽  
pp. 701-709 ◽  
Author(s):  
David Torrallardona ◽  
C. Ian Harris ◽  
Malcolm F. Fuller
Keyword(s):  
Body Weight ◽  
Isotope Ratio Mass Spectrometry ◽  
Acid Synthesis ◽  
Exchange Chromatography ◽  
The Body ◽  
Amino Acid Synthesis ◽  
Low Protein ◽  
N Enrichment ◽  
Fermentable Carbohydrates

Four rats were housed in cages with mesh floors; another four rats were housed in tubular anti-coprophagy cages, in which they could not turn round to reach their own faeces. Both groups were fed for 6 d on a low-protein diet containing fermentable carbohydrates and 15NH4Cl. At the end of the experiment the rats were killed and their carcasses were homogenized, lysine was isolated by ion-exchange chromatography and its 15N enrichment measured by isotope-ratio mass spectrometry. The 15N enrichment in the lysine of the microbial fraction of faeces and the total amount of lysine in the body were also determined in order to estimate the amount of microbial lysine absorbed. The 15N enrichment in body lysine of non-coprophagic rats was not different from that previously measured in rats given unlabelled NH4Cl, but in coprophagic rats it was significantly higher. The daily absorption of microbial lysine by the coprophagic rats accounted for 20·7 (SE 2·55) mg/kg body weight0·75 but was only 0·5 (SE 1·04) mg/kg body weight0·75 for the non-coprophagic rats. This value was not significantly different from zero. The utilization of microbial amino acids via coprophagy resulted in a higher weight gain (adjusted for intake) in the coprophagic group (15·5 g/6 d) than in the non-coprophagic rats (3·1 g/6 d). It was concluded that, in rats, the utilization of microbial lysine occurred exclusively via coprophagy.

Availability of intestinal microbial lysine for whole body lysine homeostasis in human subjects

1999 ◽  
Vol 277 (4) ◽  
pp. E597-E607 ◽  
Author(s):  
Cornelia C. Metges ◽  
Antoine E. El-Khoury ◽  
Lidewij Henneman ◽  
Klaus J. Petzke ◽  
Ian Grant ◽  
...  
Keyword(s):  
De Novo ◽  
Human Subjects ◽  
Isotope Ratio Mass Spectrometry ◽  
Acid Synthesis ◽  
Whole Body ◽  
Microbial Protein ◽  
Amino Acid Synthesis ◽  
Adequate Diet ◽  
Appearance Rate ◽  
Intravenous And Oral Administration

We have investigated whether there is a net contribution of lysine synthesized de novo by the gastrointestinal microflora to lysine homeostasis in six adults. On two separate occasions an adequate diet was given for a total of 11 days, and a 24-h (12-h fast, 12-h fed) tracer protocol was performed on the last day, in which lysine turnover, oxidation, and splanchnic uptake were measured on the basis of intravenous and oral administration ofl-[1-13C]lysine andl-[6,6-2H2]lysine, respectively. [15N2]urea or15NH4Cl was ingested daily over the last 6 days to label microbial protein. In addition, seven ileostomates were studied with15NH4Cl. [15N]lysine enrichment in fecal and ileal microbial protein, as precursor for microbial lysine absorption, and in plasma free lysine was measured by gas chromatography-combustion-isotope ratio mass spectrometry. Differences in plasma [13C]- and [2H2]lysine enrichments during the 12-h fed period were observed between the two15N tracer studies, although the reason is unclear, and possibly unrelated to the tracer form per se. In the normal adults, after15NH4Cl and [15N2]urea intake, respectively, lysine derived from fecal microbial protein accounted for 5 and 9% of the appearance rate of plasma lysine. With ileal microbial lysine enrichment, the contribution of microbial lysine to plasma lysine appearance was 44%. This amounts to a gross microbial lysine contribution to whole body plasma lysine turnover of between 11 and 130 mg ⋅ kg−1 ⋅ day−1, depending on the [15N]lysine precursor used. However, insofar as microbial amino acid synthesis is accompanied by microbial breakdown of endogenous amino acids or their oxidation by intestinal tissues, this may not reflect a net increase in lysine absorption. Thus we cannot reliably estimate the quantitative contribution of microbial lysine to host lysine homeostasis with the present paradigm. However, the results confirm the significant presence of lysine of microbial origin in the plasma free lysine pool.

scholarly journals Occurrence and significance of folic acid

Pteridines ◽  
2018 ◽  
Vol 29 (1) ◽  
pp. 187-195 ◽  
Author(s):  
Ewa Cieślik ◽  
Iwona Cieślik
Keyword(s):  
Folic Acid ◽  
Glutamic Acid ◽  
High Sensitivity ◽  
Acid Synthesis ◽  
The Body ◽  
Neural Tube Closure ◽  
Amino Acid Synthesis ◽  
Biochemical Processes ◽  
Chemical Factors ◽  
Physical And Chemical

AbstractFolic acid is a naturally occurring pteridine, which was originally isolated from plants. Folic acid (pteroyl-glutamic acid) is composed of pteridine (6-methylptero), p-aminobenzoic acid (PABA) and glutamic acid. Folic acid (folacin) is a compound of major importance for the proper functioning of the human body. Its adequate supply is essential for the proper course of many biochemical processes in the body, including the process of neural tube closure in the fetus, DNA and amino acid synthesis, growth of red blood cells, and the function of the nervous system. Folic acid is a compound of a high sensitivity to physical and chemical factors, and its bioavailability is limited by interactions with multiple food components. Therefore, folate deficiency is one of the most common deficiencies. This paper presents the structure and characteristics of folic acid as a pteridine, it also discusses dietary sources of folate and the effects of its deficiency.

Urea utilization by rabbits fed a low-protein ration

1963 ◽  
Vol 205 (6) ◽  
pp. 1144-1150 ◽  
Author(s):  
T. Richard Houpt
Keyword(s):  
Drinking Water ◽  
Amino Acid ◽  
Nitrogen Balance ◽  
Antibacterial Agents ◽  
Acid Synthesis ◽  
The Body ◽  
The Other ◽  
Nitrogen Excretion ◽  
Amino Acid Synthesis ◽  
Low Protein

Utilization of urea by adult rabbits fed straw, carrots, and sucrose was investigated. 1) In a 24-hr period following intravenous injection of 290 mg urea-N/kg body wt., part of the exogenous urea was excreted in urine and part was stored in body fluids; the remainder could not be accounted for and was presumed utilized in amino acid synthesis. An average of 212 ± 54 (sd) mg urea-N were utilized in eight such experiments (control urea-N excretion was 151 mg/day). Urea given per os over several days was also utilized. 2) When drinking water was removed, utilization of urea given per os, as reflected in nitrogen balance, increased; or, if no urea was given, nitrogen excretion decreased. 3) Antibacterial agents per os reduced exogenous urea utilization; or, if no urea was given, urea excretion increased, representing endogenous urea normally utilized (up to 40% of that formed in the body). 4) In acute experiments, blood urea moved into the saline-filled cecum at rates commensurate with the rates of utilization found in the other experiments. It was concluded that adult rabbits under these conditions can utilize urea at rates significant in nitrogen metabolism.

scholarly journals Adaptive changes in the ornithine cycle and amino acid synthesis in sheep liver with different meat productivity

2021 ◽  
Vol 12 (6) ◽  
pp. s632-s645
Author(s):  
Tetiana Prylipko ◽  
Tetiana Koval ◽  
Volodymyr Kostash ◽  
Volodymyr Tkachuk ◽  
Alina Shuliar ◽  
...  
Keyword(s):  
Glutamic Acid ◽  
Average Daily Gain ◽  
Muscle Growth ◽  
Acid Synthesis ◽  
The Body ◽  
Lower Percentage ◽  
Deficient Diet ◽  
Sharp Drop ◽  
Amino Acid Synthesis ◽  
Liver Homogenates

The aim of the research was to study the ornithine cycle as the process of fixing ammonia and the formation of urea in the body of highly productive animals. In our experiments, we used a protein-deficient diet and urea as a nitrogen substitute for nitrogen-containing materials in the diet to reveal the mechanism of action of urea on animals, in particular on the biochemical processes of the ornithine cycle. There are some differences between Bukovinian sheep of the Askanian meat-wool breed and outbreds in terms of the ability to build muscle tissue. Our study reveals that the slaughter yield and the average daily gain consumption of Bukovinian-type meat of the Askanian meat-wool breed were higher in summer and in autumn, compare with purebred sheep. Sheep of the Bukovynian type of Askanian meat-wool breed have the intensity of enzymatic formation of urea in liver homogenates that is much higher in all experiments than in outbred sheep. A sharp drop in the activity of all stages of urea formation and glutamic acid synthesis in liver homogenates and significantly weakened urea formation was found in all experiments of the fourth series in comparison with the experiments in the third series. Increased muscle growth, high nitrogen deposition, and a much lower percentage of urinary excretion of ammonia and urea nitrogen, as well as higher activity of enzymes of the ornithine cycle and glutamic acid synthesis in the Bukovinian sheep type of Askanian meat-wool breed compared to outbreeds allow concluding that ammonia and urea in highly productive animals act less as finishing products of nitrogen metabolism than in low-productive animals.

Influence of increased nutrient supply on Microcystis aeruginosa at cellular and proteomic levels

2020 ◽  
Vol 85 ◽  
pp. 47-58
Author(s):  
Y Jiang ◽  
Y Liu
Keyword(s):  
Microcystis Aeruginosa ◽  
Regulatory Protein ◽  
Acid Synthesis ◽  
Nutrient Supply ◽  
Nitrogen Supply ◽  
Nitrogen And Phosphorus ◽  
Comprehensive Description ◽  
Amino Acid Synthesis ◽  
High Nutrient ◽  
Proteomic Responses

Various studies have observed that increased nutrient supply promotes the growth of bloom-forming cyanobacteria, but only a limited number of studies have investigated the influence of increased nutrient supply on bloom-forming cyanobacteria at the proteomic level. We investigated the cellular and proteomic responses of Microcystis aeruginosa to elevated nitrogen and phosphorus supply. Increased supply of both nutrients significantly promoted the growth of M. aeruginosa and the synthesis of chlorophyll a, protein, and microcystins. The release of microcystins and the synthesis of polysaccharides negatively correlated with the growth of M. aeruginosa under high nutrient levels. Overexpressed proteins related to photosynthesis, and amino acid synthesis, were responsible for the stimulatory effects of increased nutrient supply in M. aeruginosa. Increased nitrogen supply directly promoted cyanobacterial growth by inducing the overexpression of the cell division regulatory protein FtsZ. NtcA, that regulates gene transcription related to both nitrogen assimilation and microcystin synthesis, was overexpressed under the high nitrogen condition, which consequently induced overexpression of 2 microcystin synthetases (McyC and McyF) and promoted microcystin synthesis. Elevated nitrogen supply induced the overexpression of proteins involved in gas vesicle organization (GvpC and GvpW), which may increase the buoyancy of M. aeruginosa. Increased phosphorus level indirectly affected growth and the synthesis of cellular substances in M. aeruginosa through the mediation of differentially expressed proteins related to carbon and phosphorus metabolism. This study provides a comprehensive description of changes in the proteome of M. aeruginosa in response to an increased supply of 2 key nutrients.

O-AcylTEMPOs, a Modified and Fundamental, but Unexplored Carboxylic Derivative: Recent Progress in Synthetic Applications

2019 ◽  
Vol 23 (19) ◽  
pp. 2102-2121
Author(s):  
Hiroyuki Kawafuchi ◽  
Lijian Ma ◽  
Md Imran Hossain ◽  
Tsutomu Inokuchi
Keyword(s):  
Organic Synthesis ◽  
Recent Progress ◽  
Knoevenagel Condensation ◽  
Acid Synthesis ◽  
Amino Acid Synthesis ◽  
Electrophilic Amination ◽  
Weinreb Amides ◽  
Anionic Species ◽  
Diastereoselective Addition ◽  
Carbonyl Function

O-Acylated 2,2,6,6-tetramethylpiperidine-N-oxyls (abbr. O-AcylTEMPOs) are easily available and stable carboxylic derivatives, but their utility in organic synthesis is unexplored in contrast to analogues, such as the N-methoxy-N-methylamides, known as Weinreb amides. Especially, the O–N unit of the O-acylTEMPOs dictates a fairly electronwithdrawing character for the carbonyl function. This enhances the reactivity and stability of the resulting enolate ions. Accordingly, O-acylTEMPOs allow various transformations and this review encompasses seven topics: (1) Reactivity of O-acylTEMPOs towards nucleophiles and chemoselective transformations, (2) Reactivity of anionic species derived from O-acylTEMPOs, (3) E-Selective Knoevenagel condensation of acetoacetylTEMPOs and synthesis of furans, (4) Electrocyclization of 2,4-dienones derived from acetoacetic derivatives and 2-substituted enals, (5) Diastereoselective addition of amide anion to O-(2-alkenoyl)TEMPOs and β-amino acid synthesis, (6) Thermolysis of O-acylTEMPOs, and (7) Applications for Umpolung reactions using O-benzoylTEMPOs, useful for the electrophilic amination of alkenes and alkynes.

scholarly journals Petasis vs. Strecker Amino Acid Synthesis: Convergence, Divergence and Opportunities in Organic Synthesis

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1707
Author(s):  
Wayiza Masamba
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Organic Synthesis ◽  
Acid Synthesis ◽  
Physical Sciences ◽  
Amino Acid Synthesis

α-Amino acids find widespread applications in various areas of life and physical sciences. Their syntheses are carried out by a multitude of protocols, of which Petasis and Strecker reactions have emerged as the most straightforward and most widely used. Both reactions are three-component reactions using the same starting materials, except the nucleophilic species. The differences and similarities between these two important reactions are highlighted in this review.

scholarly journals Enzymatic cascade systems for D-amino acid synthesis: progress and perspectives

2021 ◽  
Author(s):  
Anwen Fan ◽  
Jiarui Li ◽  
Yangqing Yu ◽  
Danping Zhang ◽  
Yao Nie ◽  
...  
Keyword(s):  
Amino Acid ◽  
Acid Synthesis ◽  
Amino Acid Synthesis ◽  
Cascade Systems
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