Relationship between microbial biomass and substrate induced respiration in soils amended with d- and l-isomers of amino acids

Hopkins, D. W.; Isabella, B.L.; Scott, S.E.

doi:10.1016/0038-0717(94)90314-x

Cited by 34 publications

(10 citation statements)

References 12 publications

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“…Hopkins et al 5,6) compared metabolism between D-and L-amino acids using the substrate induced respiration (SIR) method. L-glutamine and L-glutamate showed higher rates of metabolism than the corresponding D-amino acids.…”

Section: Discussionmentioning

confidence: 99%

Inhibition of Bacterial Wilt of Tomato Caused by Ralstonia solanacearum by Sugars and Amino Acids

2007

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Different sugars and amino acids were added to a conducive soil to study their effects on bacterial wilt of tomato caused by Ralstonia solanacearum YU1Rif43. The compounds were selected mainly based on the utilization ability of the pathogen and added to the soil at application rates of 0.5 to 5 mg g −1 , together with an inoculation of the pathogen. While tomato seeds germinated and grew healthy in soils amended with carbohydrates at a rate of 5 mg g −1 , most of the seeds failed to germinate in soils to which serine, glycine and alanine were applied at the same rate. At 2.5 mg g −1 , the inhibitory effect on tomato germination disappeared except for methionine. Most of the compounds decreased the incidence of wilt during 30 days of cultivation, while sucrose, fructose, threonine, acetate, and glycerol had no apparent suppressive effect. The compounds that showed the most suppressive effect were glucose, proline, glutamine, serine, arginine, and lysine. The pathogen utilized glucose, proline, and glutamine, but not serine, arginine and lysine. Certain compounds stimulated microbial activity and decreased the survival of the pathogen, and thereby suppressed bacterial wilt of tomato.

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Section: Discussionmentioning

confidence: 99%

Inhibition of Bacterial Wilt of Tomato Caused by Ralstonia solanacearum by Sugars and Amino Acids

2007

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“…Also, polymers of D-glutamic acid and L-glutamine are associated with cell walls of various bacteria (Kandler et al 1983). Based on mineralization rates in soil, D-amino acids probably represent a small fraction of the soil amino acid flux compared to L-isomers, with the possible exception of D-alanine (Hopkins et al 1994). Mayer et al (1995) found that amino acids released from sediment after incubation with proteases were depleted in methionine, and concluded that microbial coat proteins were an important source.…”

Section: Sources Of Free Amino Acidsmentioning

confidence: 97%

The unexpected versatility of plants: organic nitrogen use and availability in terrestrial ecosystems

2001

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The recently recognized importance of organic nitrogen (ON), particularly amino acids, to plant nutrition in many types of agricultural and natural ecosystems has raised questions about plant-microbe interactions, N availability in soils, and the ecological implications of ON use by plants in the light of climate change and N pollution. In this review we synthesize the recent work on availability and plant uptake of amino acids with classic work on ON in soils. We also discuss recent work on the use of natural abundance levels of (15)N to infer N sources for plants. Reliance on ON is widespread among plants from many ecosystems. Authors have reached this conclusion based on laboratory studies of amino acid uptake by plants in pure culture, amino acid concentrations in soils, plant uptake of isotopically labeled amino acids in the field and in plant-soil microcosms, and from plant natural abundance values of (15)N. The supply of amino acids to plants is determined mainly by the action of soil proteolytic enzymes, interactions between amino acids and the soil matrix, and competition between plants and microbes. Plants generally compete for a minor fraction of the total amino acid flux, but in some cases this forms a significant N resource, especially in ecosystems where microbial biomass undergoes large seasonal fluctuations and contributes labile ON to the soil. A quantitative understanding of ON use by plants is confounded by incomplete data on partitioning of ON between plants, mycorrhizal fungi, and competing soil microbes. Further research is needed to predict the ecological implications of ON use by plants given the influence of climatic change and N pollution.

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“…Four different pairs of L-and D-amino acids are important in DOM (aspartic acid, glutamic acid, serine and alanine) and the amount of D relative to L (the D/L ratio) has been used as an indicator of amino acid bioavailability (Jørgensen et al, 1999). Freshly released DOM from phytoplankton has a low D/L ratio, but the ratio increases during bacterial degradation of DOM (Amon et al, 2001) due to direct release of D-amino acids by bacteria during growth (Kawasaki and Benner, 2006); viral lysis of cells and the subsequent release of cell wall D-amino acids (Middelboe and Jørgensen, 2006); and a presumably higher bioavailability of L-amino acids (Amon et al, 2001;Hopkins et al, 1994;Pérez et al, 2003). The presence of grazers such as flagellates can also increase the bacterial uptake of D-amino acids, possibly due to a higher release from bacterivory and subsequent microbial uptake (Pérez et al, 2003).…”

Section: Jørgensen Et Al: Production and Transformation Of Dissolmentioning

confidence: 99%

Production and transformation of dissolved neutral sugars and amino acids by bacteria in seawater

et al. 2014

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Abstract. Dissolved organic matter (DOM) in the ocean consists of a heterogeneous mixture of molecules, most of which are of unknown origin. Neutral sugars and amino acids are among the few recognizable biomolecules in DOM, and the molecular composition of these biomolecules is shaped primarily by biological production and degradation processes. This study provides insight into the bioavailability of biomolecules as well as the chemical composition of DOM produced by bacteria. The molecular compositions of combined neutral sugars and amino acids were investigated in DOM produced by bacteria and in DOM remaining after 32 days of bacterial degradation. Results from bioassay incubations with natural seawater (sampled from water masses originating from the surface waters of the Arctic Ocean and the North Atlantic Ocean) and artificial seawater indicate that the molecular compositions following bacterial degradation are not strongly influenced by the initial substrate or bacterial community. The molecular composition of neutral sugars released by bacteria was characterized by a high glucose content (47 mol %) and heterogeneous contributions from other neutral sugars (3-14 mol %). DOM remaining after bacterial degradation was characterized by a high galactose content (33 mol %), followed by glucose (22 mol %) and the remaining neutral sugars (7-11 mol %). The ratio of D-amino acids to L-amino acids increased during the experiments as a response to bacterial degradation, and after 32 days, the D/L ratios of aspartic acid, glutamic acid, serine and alanine reached around 0.79, 0.32, 0.30 and 0.51 in all treatments, respectively. The striking similarity in neutral sugar and amino acid compositions between natural (representing marine semi-labile and refractory DOM) and artificial (representing bacterially produced DOM) seawater samples, suggests that microbes transform bioavailable neutral sugars and amino acids into a common, more persistent form.

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Relationship between microbial biomass and substrate induced respiration in soils amended with d- and l-isomers of amino acids

Cited by 34 publications

References 12 publications

Inhibition of Bacterial Wilt of Tomato Caused by Ralstonia solanacearum by Sugars and Amino Acids

Inhibition of Bacterial Wilt of Tomato Caused by Ralstonia solanacearum by Sugars and Amino Acids

The unexpected versatility of plants: organic nitrogen use and availability in terrestrial ecosystems

Production and transformation of dissolved neutral sugars and amino acids by bacteria in seawater

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