Microbial protein metabolism in the monogastric gastrointestinal tract: a review

2022 ◽  
pp. 435-466
Author(s):  
Kim C. M. Lammers-Jannink ◽  
◽  
Stefanía Magnúsdóttir ◽  
Wilbert F. Pellikaan ◽  
John Pluske ◽  
...  
Keyword(s):  
Gastrointestinal Tract ◽  
Protein Metabolism ◽  
Building Blocks ◽  
Substrate Availability ◽  
Microbial Protein ◽  
Microbial Composition ◽  
Catabolic Pathways ◽  
Microbial Cells ◽  
Endogenous Protein ◽  
End Products

Dietary and endogenous protein that become available for the microbiota in the hindgut can be metabolized via different routes. They can become building blocks for the microbial cells or enter different catabolic pathways. Protein degradation via fermentation pathways is seen as a non-preferred route as it results in the formation and release of metabolites that can interfere with biological systems in the host and can have deleterious outcomes. Reducing protein fermentation and guiding the metabolism towards less toxic end-products might be possible targets for improving host health. To do so, more knowledge on factors manipulating the process of microbial protein metabolism, including on substrate availability, microbial composition and segmental differences in the hindgut, is required.

The Excretion of Isotope in Urea and Ammonia for Estimating Protein Turnover in Man with [15N]Glycine

1981 ◽  
Vol 61 (2) ◽  
pp. 217-228 ◽  
Author(s):  
E. B. Fern ◽  
P. J. Garlick ◽  
Margaret A. McNurlan ◽  
J. C. Waterlow
Keyword(s):  
Protein Metabolism ◽  
Protein Turnover ◽  
Mean Value ◽  
Intravenous Dose ◽  
Whole Body ◽  
Body Protein ◽  
End Products ◽  
The Mean ◽  
15N Urea ◽  
Normal Adults

1. Four normal adults were given [15N]-glycine in a single dose either orally or intravenously. Rates of whole-body protein turnover were estimated from the excretion of 15N in ammonia and in urea during the following 9 h. The rate derived from urea took account of the [15N]urea retained in body water. 2. In postabsorptive subjects the rates of protein synthesis given by ammonia were equal to those from urea, when the isotope was given orally, but lower when an intravenous dose was given. 3. In subjects receiving equal portions of food every 2 h rates of synthesis calculated from ammonia were much lower than those from urea whether an oral or intravenous isotope was given. Comparison of rates obtained during the post-absorptive and absorptive periods indicated regulation by food intake primarily of synthesis when measurements were made on urea, but regulation primarily of breakdown when measurements were made on ammonia. 4. These inconsistencies suggest that changes in protein metabolism might be assessed better by correlating results given by different end-products, and it is suggested that the mean value given by urea and ammonia will be useful for this purpose.

scholarly journals A model for estimating endogenous protein flows in the gastrointestinal tract of ruminants

1997 ◽  
Vol 6 (3) ◽  
pp. 289-301 ◽  
Author(s):  
A. Assis ◽  
J. France ◽  
J. Dijkstra ◽  
D. Veira
Keyword(s):  
Gastrointestinal Tract ◽  
Endogenous Protein

scholarly journals Construction of the microbial protein metabolism map of tea rhizosphere soil in acidified plantations

2020 ◽  
Vol 50 (8) ◽  
pp. 849-865
Author(s):  
HaiBin HE ◽  
HaiBin WANG ◽  
Qi ZHANG ◽  
JiangHua YE ◽  
Sheng LIN ◽  
...  
Keyword(s):  
Protein Metabolism ◽  
Rhizosphere Soil ◽  
Microbial Protein

scholarly journals Effects of Long-Term Triclosan Exposure on Microbiota in Zebrafish

2021 ◽  
Vol 12 ◽  
Author(s):  
Ning Tang ◽  
Pianpian Fan ◽  
Xiaogang Yu ◽  
Rui Ma ◽  
Yexuan Tao ◽  
...  
Keyword(s):  
Gastrointestinal Tract ◽  
Early Adulthood ◽  
Rrna Gene ◽  
Adult Zebrafish ◽  
Short Term ◽  
Microbial Composition ◽  
Short Term Exposure ◽  
Embryonic Life ◽  
A Minor

Background: Triclosan (TCS) is a widely used antibacterial agent in personal care products and is ubiquitous in the environment. We aimed to examine whether TCS exposure affects microbiota in the gastrointestinal tract of zebrafish.Methods: After exposure to TCS 0 (Dimethyl Sulphoxide, DMSO control), 0.03, 0.3, 3, 30, 100, and 300ng/ml, respectively, from day 0 to 120days post fertilization (dpf), or for 7days in adult 4-month zebrafish, the long- and short-term impact of TCS exposure on the microbiome in the gastrointestinal tract was evaluated by analyzing 16S rRNA gene V3-V4 region sequencing.Results: The top two most dominant microbiota phyla were Proteobacteria and Fusobacteria phylum in all zebrafish groups. In TCS exposure 0–120 dpf, compared with DMSO control, the mean number of microbial operational taxonomic units (OTUs) was 54.46 lower (p<0.0001), Chao indice 41.40 lower (p=0.0004), and Ace indice 34.10 lower (p=0.0044) in TCS 300ng/ml group, but no change was observed in most of the other TCS concentrations. PCoA diagram showed that the microbial community in the long-term TCS 300ng/ml exposure group clustered differently from those in the DMSO control and other TCS exposure groups. A shorter body length of the zebrafish was observed in the long-term TCS exposure at 0.03, 100, and 300ng/ml. For 7-day short-term exposure in adult zebrafish, no difference was observed in alpha or beta diversity of microbiota nor the relative abundance of Proteobacteria or Fusobacteria phylum among DMSO control and any TCS levels, but a minor difference in microbial composition was observed for TCS exposure.Conclusions: Long-term exposure to high TCS concentration in a window from early embryonic life to early adulthood may reduce diversity and alter the composition of microbiota in the gastrointestinal tract. The effect of short-term TCS exposure was not observed on the diversity of microbiota but there was a minor change of microbial composition in adult zebrafish with TCS exposure.

scholarly journals Polyphenols by Generating H2O2, Affect Cell Redox Signaling, Inhibit PTPs and Activate Nrf2 Axis for Adaptation and Cell Surviving: In Vitro, In Vivo and Human Health

Antioxidants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 797 ◽  
Author(s):  
Joseph Kanner
Keyword(s):  
Oxidative Stress ◽  
Gastrointestinal Tract ◽  
Human Health ◽  
Blood System ◽  
Cytotoxic Agents ◽  
Related Factor ◽  
High Concentration ◽  
Oxidation Stress ◽  
End Products

Human health benefits from different polyphenols molecules consumption in the diet, derived mainly by their common activities in the gastrointestinal tract and at the level of blood micro-capillary. In the stomach, intestine and colon, polyphenols act as reducing agents preventing lipid peroxidation, generation and absorption of AGEs/ALEs (advanced glycation end products/advanced lipid oxidation end products) and postprandial oxidative stress. The low absorption of polyphenols in blood does not support their activity as antioxidants and their mechanism of activity is not fully understood. The results are from in vitro, animal and human studies, detected by relevant oxidative stress markers. The review carries evidences that polyphenols, by generating H2O2 at nM concentration, exogenous to cells and organs, act as activators of signaling factors increasing cell Eustress. When polyphenols attain high concentration in the blood system, they generate H2O2 at µM concentration, acting as cytotoxic agents and Distress. Pre-treatment of cells or organisms with polyphenols, by generating H2O2 at low levels, inhibits cellular PTPs (protein tyrosine phosphatases), inducing cell signaling through transcription of the Nrf2 (nuclear factor erythroid 2-related factor 2) axis of adaptation and protection to oxidation stress. Polyphenols ingestion at the right amount and time during the meal acts synergistically at the level of the gastrointestinal tract (GIT) and blood system, for keeping the redox homeostasis in our organism and better balancing human health.

scholarly journals Spatial and Temporal Analysis of the Stomach and Small-Intestinal Microbiota in Fasted Healthy Humans

mSphere ◽  
2019 ◽  
Vol 4 (2) ◽  
Author(s):  
Anna M. Seekatz ◽  
Matthew K. Schnizlein ◽  
Mark J. Koenigsknecht ◽  
Jason R. Baker ◽  
William L. Hasler ◽  
...  
Keyword(s):  
Gastrointestinal Tract ◽  
Upper Gastrointestinal Tract ◽  
Rrna Gene ◽  
Gi Tract ◽  
Microbial Composition ◽  
Content Type ◽  
Healthy Humans ◽  
Health And Disease ◽  
Upper Gastrointestinal ◽  
Over Time

ABSTRACTAlthough the microbiota in the proximal gastrointestinal (GI) tract have been implicated in health and disease, much about these microbes remains understudied compared to those in the distal GI tract. This study characterized the microbiota across multiple proximal GI sites over time in healthy individuals. As part of a study of the pharmacokinetics of oral mesalamine administration, healthy, fasted volunteers (n = 8; 10 observation periods total) were orally intubated with a four-lumen catheter with multiple aspiration ports. Samples were taken from stomach, duodenal, and multiple jejunal sites, sampling hourly (≤7 h) to measure mesalamine (administered att = 0), pH, and 16S rRNA gene-based composition. We observed a predominance ofFirmicutesacross proximal GI sites, with significant variation compared to stool. The microbiota was more similar within individuals over time than between subjects, with the fecal microbiota being unique from that of the small intestine. The stomach and duodenal microbiota displayed highest intraindividual variability compared to jejunal sites, which were more stable across time. We observed significant correlations in the duodenal microbial composition with changes in pH; linear mixed models identified positive correlations with multipleStreptococcusoperational taxonomic units (OTUs) and negative correlations with multiplePrevotellaandPasteurellaceaeOTUs. Few OTUs correlated with mesalamine concentration. The stomach and duodenal microbiota exhibited greater compositional dynamics than the jejunum. Short-term fluctuations in the duodenal microbiota were correlated with pH. Given the unique characteristics and dynamics of the proximal GI tract microbiota, it is important to consider these local environments in health and disease states.IMPORTANCEThe gut microbiota are linked to a variety of gastrointestinal diseases, including inflammatory bowel disease. Despite this importance, microbiota dynamics in the upper gastrointestinal tract are understudied. Our article seeks to understand what factors impact microbiota dynamics in the healthy human upper gut. We found that the upper gastrointestinal tract contains consistently prevalent bacterial OTUs that dominate the overall community. Microbiota variability is highest in the stomach and duodenum and correlates with pH.

A note on the flow of endogenous protein to the omasum and abomasum of steers

1990 ◽  
Vol 51 (1) ◽  
pp. 217-219 ◽  
Author(s):  
F. J. Hart ◽  
Jane Leibholz
Keyword(s):  
Food Intake ◽  
Sodium Hydroxide ◽  
Wheat Straw ◽  
Dry Matter ◽  
Dry Matter Intake ◽  
Microbial Protein ◽  
Protein Nitrogen ◽  
Endogenous Protein ◽  
Digestible Protein

Three steers cannulated in the rumen and abomasum were given a diet of wheat straw, chopped and soaked in sodium hydroxide and then washed to pH less than 8. The straw was sprayed with sucrose, urea and minerals. The diet was free of digestible protein and given at 1·7 to 4·1 kg/day. Microbial protein flowing to the omasum was measured by 15N. By difference, the flow of endogenous protein nitrogen to the omasum was found to be 2·2 g/kg dry-matter intake. The flow of endogenous protein nitrogen to the abomasum was 3·3 to 9·4 g/kg dry-matter intake, and it decreased with increasing food intake.

Leucine metabolism across the gastrointestinal tract of sheep infected with Trichostrongylus colubriformis

1998 ◽  
Vol 1998 ◽  
pp. 1-1 ◽  
Author(s):  
Feng Yu ◽  
L.A. Bruce ◽  
R.L. Coop ◽  
J.C. MacRae
Keyword(s):  
Immune Response ◽  
Protein Synthesis ◽  
Gastrointestinal Tract ◽  
Protein Metabolism ◽  
Farm Animals ◽  
Tracer Kinetics ◽  
Trichostrongylus Colubriformis ◽  
Initial Infection ◽  
Leucine Metabolism ◽  
Isotope Tracer

In previous studies where sheep were subjected to experimental subclinical Trichostrongylus colubriformis infections, protein metabolism was seriously impaired during both the initial infection (5-7 weeks at early dosing) and the subsequent immune response (11-13 weeks of dosing) periods (see MacRae, 1993). Symonds and Jones (1983) reported that T. colubriformis infection increased the rates of protein synthesis in the small and large intestines of guinea pigs by 24 and 70% respectively, however there are no equivalent data in farm animals. In the present study trans-organ catheterisation procedures have been coupled with mass isotope tracer kinetics to examine leucine metabolism across the gastrointestinal (g.i.) tract of lambs subjected to subclinical T. colubriformis infection.

The anaerobic end-products of helminths

Parasitology ◽  
1984 ◽  
Vol 88 (1) ◽  
pp. 179-198 ◽  
Author(s):  
J. Barrett
Keyword(s):  
Carbon Dioxide ◽  
Tricarboxylic Acid Cycle ◽  
Metabolic Cost ◽  
Product Formation ◽  
Carbon Dioxide Fixation ◽  
Functional Adaptation ◽  
Catabolic Pathways ◽  
Parasitic Helminths ◽  
Wide Range ◽  
End Products

Parasitic helminths belong to 3 separate phyla and there is always the danger of over-generalization. The various routes of anaerobic carbohydrate breakdown in parasitic helminth differ in their efficiencies and in their power output. The choice of end-product represents a compromise between these two conflicting forces. In addition, anaerobic pathways must satisfy the redox requirements of the tissues and provide a source of intermediates for synthetic reactions. Other considerations include the metabolic cost of excretion and the effect of end-products on protein structure and function. The different end-products may fulfil additional functions such as pH control, nitrogenous excretion, osmotic regulation, intracellular signalling and the suppression of host responses.A complicating factor in parasitic helminths is the existence of strains with different biochemical characteristics, including marked variation in end-product formation. The various tissues of the same parasite can also produce different end-products and the pattern of end-product formation is influenced by a variety of extrinsic and intrinsic factors such as age, sex, length of incubation, pO2 and availability of substrates. The catabolic pathways of helminths thus show considerable functional adaptation.There is, as yet, no satisfactory explanation as to why helminths do not make the maximum use of any oxygen available to them; and the contribution of oxidative processes to the overall energy balance of parasites probably varies from species to species.The catabolic pathways of adult helminths are derived from the anaerobic pathways present in their free-living relatives. Two main trends are evident, homolactic fermentation and carbon dioxide fixation, the latter involving a partial reverse tricarboxylic acid cycle. In general, homolactic fermentation is found in blood and tissue parasites, carbon dioxide fixation in gut parasites. These two types of metabolism are, of course, in no way absolute, most homolactic fermentors fix carbon dioxide to a certain extent and many parasites which fix carbon dioxide also produce lactate. Parasitic helminths possess a wide range of different catabolic pathways, superimposed upon which is a high degree of functional plasticity.

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