Growth-Limiting Nutrients in Sphagnum-Dominated Bogs Subject to Low and High Atmospheric Nitrogen Supply

1992 ◽  
Vol 80 (1) ◽  
pp. 131 ◽  
Author(s):  
Rien Aerts ◽  
Bo Wallen ◽  
Nils Malmer
1958 ◽  
Vol 35 (3) ◽  
pp. 626-638
Author(s):  
T. E. MITTLER

1. The investigation concerns the ingestion, excretion, and assimilation of dietary nitrogen by Tuberolachnus salignus (Gmelin) developing on Salix trees in various stages of leaf development. 2. Apterous and alate forms of T. salignus differ in their rates of development and nitrogen assimilation and in their behaviour. 3. The aphids assimilate considerably more nitrogen when developing on willows having a phloem sap rich in nitrogen than on willows having a phloem sap relatively poor in nitrogen. 4. For a given amount of nitrogen assimilated the aphids ingest a larger volume of a phloem sap poor in nitrogen than of a phloem sap rich in nitrogen. 5. Nitrogen balance experiments have shown that T. salignus nymphs assimilate only as much nitrogen as they are able to absorb from their food. 6. The evidence for and against the fixation of atmospheric nitrogen by aphids through the agency of their symbionts is briefly discussed. T. salignus do not supplement their dietary nitrogen supply by fixing atmospheric nitrogen.


2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Lena Waidele ◽  
Judith Korb ◽  
Christian R. Voolstra ◽  
Franck Dedeine ◽  
Fabian Staubach

Abstract Background Elucidating the interplay between hosts and their microbiomes in ecological adaptation has become a central theme in evolutionary biology. A textbook example of microbiome-mediated adaptation is the adaptation of lower termites to a wood-based diet, as they depend on their gut microbiome to digest wood. Lower termites have further adapted to different life types. Termites of the wood-dwelling life type never leave their nests and feed on a uniform diet. Termites of the foraging life type forage for food outside the nest and have access to other nutrients. Here we sought to investigate whether the microbiome that is involved in food substrate breakdown and nutrient acquisition might contribute to adaptation to these dietary differences. We reasoned that this should leave ecological imprints on the microbiome. Results We investigated the protist and bacterial microbiomes of a total of 29 replicate colonies from five termite species, covering both life types, using metagenomic shotgun sequencing. The microbiome of wood-dwelling species with a uniform wood diet was enriched for genes involved in lignocellulose degradation. Furthermore, metagenomic patterns suggest that the microbiome of wood-dwelling species relied primarily on direct fixation of atmospheric nitrogen, while the microbiome of foraging species entailed the necessary pathways to utilize nitrogen in the form of nitrate for example from soil. Conclusion Our findings are consistent with the notion that the microbiome of wood-dwelling species bears an imprint of its specialization on degrading a uniform wood diet, while the microbiome of the foraging species might reflect its adaption to access growth limiting nutrients from more diverse sources. This supports the idea that specific subsets of functions encoded by the microbiome can contribute to host adaptation.


2019 ◽  
Author(s):  
Lena Waidele ◽  
Judith Korb ◽  
Christian R Voolstra ◽  
Franck Dedeine ◽  
Fabian Staubach

AbstractBackgroundElucidating the interplay between hosts and their microbiomes in ecological adaptation has become a central theme in evolutionary biology. A textbook example of microbiome-mediated adaptation is the adaptation of lower termites to a wood-based diet, as they depend on their gut microbiome to digest wood. Lower termites have further adapted to different life types. Termites of the wood-dwelling life type never leave their nests and feed on a uniform diet. Termites of the foraging life type forage for food outside the nest and have access to other nutrients. Here we sought to investigate whether the microbiome that is involved in food substrate breakdown and nutrient acquisition might contribute to adaptation to these ecological differences. We reasoned that this should leave ecological imprints on the microbiome.ResultsWe investigated the protist and bacterial microbiomes of a total of 29 replicate colonies from five termite species, covering both life types, using metagenomic shotgun sequencing. The microbiome of wood-dwelling species with a uniform wood diet was enriched for genes involved in lignocellulose degradation. Furthermore, metagenomic patterns suggest that the microbiome of wood-dwelling species relied primarily on direct fixation of atmospheric nitrogen, while the microbiome of foraging species entailed the necessary pathways to utilize nitrogen in the form of nitrate for example from soil.ConclusionOur findings are consistent with the notion that the microbiome of wood-dwelling species bears an imprint of its specialization on degrading a uniform wood diet, while the microbiome of the foraging species might reflect its adaption to access growth limiting nutrients from more diverse sources. This supports the idea that specific subsets of functions encoded by the microbiome can contribute to host adaptation.


1997 ◽  
Vol 101 (4) ◽  
pp. 764-769 ◽  
Author(s):  
Heike Stoermer ◽  
Bettina Seith ◽  
Ulrike Hanemann ◽  
Eckhard George ◽  
Heinz Rennenberg

2020 ◽  
Vol 85 ◽  
pp. 47-58
Author(s):  
Y Jiang ◽  
Y Liu

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.


2014 ◽  
Vol 1 (3) ◽  
pp. 57-61
Author(s):  
E. Kopylov

Aim. To study the specifi cities of complex inoculation of spring wheat roots with the bacteria of Azospirillum genus and Chaetomium cochliodes Palliser 3250, and the isolation of bacteria of Azospirillum genus, capable of fi xing atmospheric nitrogen, from the rhizospheric soil, washed-off roots and histoshere. Materials and meth- ods. The phenotypic features of the selected bacteria were identifi ed according to Bergi key. The molecular the polymerase chain reaction and genetic analysis was used for the identifi cation the bacteria. Results. It has been demonstrated that during the introduction into the root system of spring wheat the strain of A. brasilensе 102 actively colonizes rhizospheric soil, root surface and is capable of penetrating into the inner plant tissues. Conclusions. The soil ascomucete of C. cochliodes 3250 promotes better settling down of Azospirillum cells in spring wheat root zone, especially in plant histosphere which induces the increase in the content of chlorophyll a and b in the leaves and yield of the crop.


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