Isotopic fractionation of nitrogen and carbon in the synthesis of amino acids by microorganisms

Macko, Stephen A.; Fogel, Marilyn L.; Hare, P. E.; Hoering, Thomas C.

doi:10.1016/0168-9622(87)90064-9

Cited by 503 publications

(256 citation statements)

References 20 publications

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“…Other compounds, especially amino acids, may be enriched or depleted in both 13 C and 24 15 N depending on the specific compound and the substrate on which the organisms that produce 25 the compounds are grown (Macko et al, 1987;Hayes, 2001;Abraham and Hesse, 2003 Our results also imply that sorption of peptidic organics to soil mineral particles is a potentially 4 important process of C and N stabilization and deserves further study. To the extent that the N-5 containing organics sorb mainly electrostatically, and the non-N-containing organics sorb mainly 6 via ligand exchange and weaker interactions, nitrogenous and non-nitrogenous compounds are 7 stabilized via different mechanisms.…”

Section: Mineralogy Of the Bulk Soil And Density Fractions 10 11mentioning

confidence: 64%

“…Additionally, SOM plays 21 critical roles in governing agricultural and forest soil dynamics and ecosystem productivity. Soil 22 organic matter (OM) dynamics are complex, requiring understanding of biological and chemical 23 interactions between organic compounds and mineral soil constituents. In mineral soil, OM 24 accumulates mainly on and around surfaces of silt-and clay-size particles.…”

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confidence: 99%

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Organic C and N stabilization in a forest soil: Evidence from sequential density fractionation

Sollins

Swanston

Kleber

et al. 2006

Soil Biology and Biochemistry

399

271

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Section: Mineralogy Of the Bulk Soil And Density Fractions 10 11mentioning

confidence: 64%

mentioning

confidence: 99%

Organic C and N stabilization in a forest soil: Evidence from sequential density fractionation

Sollins

Swanston

Kleber

et al. 2006

Soil Biology and Biochemistry

399

271

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“…In the present study, rumen bacteria were 15 N enriched relative to diets (average of 0.93‰) in agreement with in vivo studies (Sutoh et al, 1987 (average of 2.17‰) ; Sutoh et al, 1993 (average of 3.29‰)), but not with in vitro assays (Wattiaux and Reed, 1995 (rumen bacteria depleted in 15 N relative to substrates)). Isotopic N fractionation in bacteria may occur during assimilation, synthesis, transfer and excretion of N compounds (Macko et al, 1987). However, fractionation during AA assimilation seemed minimal in pure culture bacteria (Macko and Estep, 1984) and mixed cultures of rumen bacteria (Wattiaux and Reed, 1995).…”

Section: Discussionmentioning

confidence: 99%

Relationship between efficiency of nitrogen utilization and isotopic nitrogen fractionation in dairy cows: contribution of digestion v. metabolism?

Cantalapiedra-Hijar

Fouillet

Huneau

et al. 2016

animal

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Animal tissues are naturally 15 N enriched relative to their diet and the extent of this difference (Δ 15 N animal-diet ) has been correlated to the efficiency of N assimilation in different species. The rationale is that transamination and deamination enzymes, involved in amino acid metabolism are likely to preferentially convert amino groups containing 14 N over 15 N. However, in ruminants the contribution of rumen bacterial metabolism relative to animal tissues metabolism to naturally enrich animal proteins in terms of 15 N has been not assessed yet. The objective of this study was to assess the impact of rumen and digestion processes on the relationship between Δ 15 N animal-diet and efficiency of N utilization for milk protein yield (milk N efficiency (MNE); milk N yield/N intake) as well as the relationship between the 15 N natural abundance of rumen bacteria and the efficiency of N use at the rumen level. Solid-and liquid-associated rumen bacteria, duodenal digesta, feces and plasma proteins were obtained (n = 16) from four lactating Holstein cows fed four different diets formulated at two metabolizable protein supplies (80% v. 110% of protein requirements) crossed by two different dietary energy source (diets rich in starch v. fiber). We measured the isotopic N fractionation between animal and diet (Δ 15 N animal-diet ) in these different body pools. The Δ 15 N animal-diet was negatively correlated with MNE when measured in solid-associated rumen bacteria, duodenal digesta, feces and plasma proteins, with the strongest correlation found for the latter. However, our results showed a very weak 15 N enrichment of duodenal digesta (Δ 15 N duodenal digesta-diet mean value = 0.42) compared with that observed in plasma proteins (Δ 15 N plasma protein-diet mean value = 2.41). These data support the idea that most of the isotopic N fractionation observed in ruminant proteins (Δ 15 N plasma protein-diet ) has a metabolic origin with very little direct impact of the overall digestion process on the existing relationship between Δ 15 N plasma protein-diet and MNE. The 15 N natural abundance of rumen bacteria was not related to either rumen N efficiency (microbial N/available N) or digestive N efficiency (metabolizable protein supply/CP intake), but showing a modest positive correlation with rumen ammonia concentration. When using diets not exceeding recommended protein levels, the contribution of rumen bacteria and digestion to the isotopic N fractionation between animal proteins and diet is low. In our conditions, most of the isotopic N fractionation (Δ 15 N plasma protein-diet ) could have a metabolic origin, but more studies are warranted to confirm this point with different diets and approaches. ImplicationsThe difference in the natural abundance of 15 N between an animal and its diet (Δ 15 N animal-diet ) is a good biomarker for predicting the efficiency of N utilization. Our results in dairy cows fed diets not exceeding recommended protein levels demonstrate that digestion processes contribute little to the r...

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“…Chironomids excrete nitrogen in the form of ammonium directly into the tube and overlying water (Devine and Vanni 2002). Elevated ammonium concentrations provide an ideal N substrate for bacterial metabolism and via essential fractionation of ammonia can result in a 15 N-depleted microbial community (Macko et al 1987;Macko and Ostrom 1994). Methanotrophic bacteria are also capable of oxidizing ammonium (Lee and Childress 1994) and thus are likely to exhibit correspondingly light ␦ 15 N values.…”

Section: Discussionmentioning

confidence: 99%

High intraspecific variability in carbon and nitrogen stable isotope ratios of lake chironomid larvae

Grey

Kelly

Jones

2004

Limnology & Oceanography

105

112

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Stable isotope analyses of chironomid trophic interactions have recently indicated the potential importance of isotopically light biogenic methane as a carbon source. Mass balance of isotope ratios suggests that small proportional differences in ingestion of such an isotopically distinct basal resource by individual consumers can result in considerable intraspecific variability. To test this, we collected individual larvae of two closely related chironomid species (Chironomus anthracinus and Chironomus plumosus) from six lakes and analyzed their ␦ 13 C and ␦ 15N. Intraspecific variability in larval ␦ 13 C and ␦ 15 N values was greater in lakes where chironomids were more 13 C depleted. C. plumosus exhibited higher intraspecific variability relative to C. anthracinus. In two lakes, individual C. plumosus exhibited a range of 35‰ for ␦ 13 C and 16‰ for ␦ 15 N (equivalent to five trophic levels). There was a strong positive relationship between larval ␦ 13 C and ␦ 15 N, both between individuals from the same lake and also between lakes, suggesting that the underlying causative mechanisms are similar. Furthermore, larvae from deeper sites, which are more susceptible to prolonged anoxia, exhibited greater intraspecific variability, and larger larvae were significantly 13 C depleted. Such high intraspecific variability can confound the interpretation of benthic food web stable isotope values. We advocate the reporting of more intraspecific isotopic variability as a means to further examine niche breadth and feeding behavior.

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Isotopic fractionation of nitrogen and carbon in the synthesis of amino acids by microorganisms

Cited by 503 publications

References 20 publications

Organic C and N stabilization in a forest soil: Evidence from sequential density fractionation

Organic C and N stabilization in a forest soil: Evidence from sequential density fractionation

Relationship between efficiency of nitrogen utilization and isotopic nitrogen fractionation in dairy cows: contribution of digestion v. metabolism?

High intraspecific variability in carbon and nitrogen stable isotope ratios of lake chironomid larvae

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