scholarly journals Algal-fungal symbiosis leads to photosynthetic mycelium

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Zhi-Yan Du ◽  
Krzysztof Zienkiewicz ◽  
Natalie Vande Pol ◽  
Nathaniel E Ostrom ◽  
Christoph Benning ◽  
...  
Keyword(s):  
Physical Contact ◽  
Biofuel Production ◽  
Nitrogen Transfer ◽  
Free Living ◽  
Important Species ◽  
Carbon And Nitrogen ◽  
Isotope Tracer ◽  
Fungal Symbiosis ◽  
Mortierella Elongata ◽  
Tracer Experiments

Mutualistic interactions between free-living algae and fungi are widespread in nature and are hypothesized to have facilitated the evolution of land plants and lichens. In all known algal-fungal mutualisms, including lichens, algal cells remain external to fungal cells. Here, we report on an algal–fungal interaction in which Nannochloropsis oceanica algal cells become internalized within the hyphae of the fungus Mortierella elongata. This apparent symbiosis begins with close physical contact and nutrient exchange, including carbon and nitrogen transfer between fungal and algal cells as demonstrated by isotope tracer experiments. This mutualism appears to be stable, as both partners remain physiologically active over months of co-cultivation, leading to the eventual internalization of photosynthetic algal cells, which persist to function, grow and divide within fungal hyphae. Nannochloropsis and Mortierella are biotechnologically important species for lipids and biofuel production, with available genomes and molecular tool kits. Based on the current observations, they provide unique opportunities for studying fungal-algal mutualisms including mechanisms leading to endosymbiosis.

Carbon and nitrogen transfer in leaf litter mixtures

2013 ◽  
Vol 57 ◽  
pp. 341-348 ◽  
Author(s):  
S. Linnea Berglund ◽  
Göran I. Ågren ◽  
Alf Ekblad
Keyword(s):  
Leaf Litter ◽  
Nitrogen Transfer ◽  
Carbon And Nitrogen ◽  
Litter Mixtures

scholarly journals The Rhizobium leguminosarum bv. viciae VF39 γ-aminobutyrate (GABA) aminotransferase gene (gabT) is induced by GABA and highly expressed in bacteroids The GenBank accession number for the sequence determined in this work is AF335502.

Microbiology ◽  
2002 ◽  
Vol 148 (2) ◽  
pp. 615-623 ◽  
Author(s):  
Jürgen Prell ◽  
Bert Boesten ◽  
Philip Poole ◽  
Ursula B Priefer
Keyword(s):  
Rhizobium Leguminosarum ◽  
Free Living ◽  
Carbon And Nitrogen ◽  
Gaba Aminotransferase ◽  
Gaba Metabolism ◽  
Promoter Probe ◽  
Promoter Probe Vector ◽  
Oxoglutarate Dehydrogenase ◽  
Substrate Specifities ◽  
Free Living Conditions

A Rhizobium leguminosarum bv. viciae VF39 gene (gabT) encoding a γ-aminobutyrate (GABA) aminotransferase was identified, cloned and characterized. This gene is thought to be involved in GABA metabolism via the GABA shunt pathway, a theoretical bypass of the 2-oxoglutarate dehydrogenase complex. Mutants in gabT are still able to grow on GABA as a sole carbon and nitrogen source. 2-Oxoglutarate-dependent GABA aminotransferase activity is absent in these mutants, while pyruvate-dependent activity remains unaffected. This indicates that at least two enzymes with different substrate specifities are involved in the GABA metabolism of R. leguminosarum bv. viciae VF39. The gabT promoter was cloned into a newly constructed, stable promoter-probe vector pJP2, suitable for the study of transcriptional GUS fusions in free-living bacteria and during symbiosis. Under free-living conditions the gabT promoter is induced by GABA and repressed by succinate. Transcriptional regulation is mediated by GabR in a repressor-like manner. During symbiosis with the pea host plant gabT is induced and highly expressed in the symbiotic zone. Nodules induced by gabT mutants, however, are still effective in nitrogen fixation.

Effects on Carbon and Nitrogen Emissions due to Swine Manure Removal for Biofuel Production

2012 ◽  
Vol 41 (5) ◽  
pp. 1371-1382 ◽  
Author(s):  
Kim H. Weaver ◽  
Lowry A. Harper ◽  
Sarah M. Brown
Keyword(s):  
Swine Manure ◽  
Biofuel Production ◽  
Nitrogen Emissions ◽  
Carbon And Nitrogen

Temporal and spatial variability of 13C/12C and 15N/14N in pelagic biota of Prince William Sound, Alaska

1999 ◽  
Vol 56 (S1) ◽  
pp. 94-117 ◽  
Author(s):  
Thomas C Kline, Jr.
Keyword(s):  
Stable Isotope ◽  
Phytoplankton Bloom ◽  
Gulf Of Alaska ◽  
Prince William Sound ◽  
Large Herbivore ◽  
Clupea Pallasi ◽  
Carbon Cycles ◽  
Isotopic Signatures ◽  
Carbon And Nitrogen ◽  
Isotope Tracer

Stable isotope ratios of carbon and nitrogen were used to identify seasonal and spatial patterns in carbon and nitrogen and to determine source of energy (Prince William Sound (PWS) versus the Gulf of Alaska (GOA)) for juvenile fishes in PWS. PWS-wide samples of bulk net zooplankton (all noncalcareous zooplankton collected in 335-µm-mesh nets), individual late copepodid stage of the large herbivore Neocalanus cristatus, juvenile Pacific herring (Clupea pallasi), and juvenile walleye pollock (Theragra chalcogramma) were collected in spring, summer, and fall in 1994 and 1995. For bulk zooplankton and N. cristatus, there was a strong 13C/12C gradient but weak 15N/14N gradient within PWS and GOA. Zooplankton 15N/14N was positively correlated with 13C/12C during the phytoplankton bloom but was not correlated during the zooplankton bloom, suggesting a decoupling of nitrogen and carbon cycles. Plankton isotopic signatures suggested a diagnostic 13C/12C for GOA carbon. For juvenile fishes and diapausing copepods in PWS, 13C/12C varied between years, suggesting that the origin of carbon differed between years (GOA more so in 1995 than in 1994). Use of a natural stable isotope tracer provided evidence for biophysical coupling via inferred fluctuations in oceanographic processes.

scholarly journals EFFECTS OF VESICULAR-ARBUSCULAR MYCORRHIZA ON 14C AND 15N DISTRIBUTION IN NODULATED FABABEANS

1980 ◽  
Vol 60 (2) ◽  
pp. 241-250 ◽  
Author(s):  
P. C. PANG ◽  
E. A. PAUL
Keyword(s):  
Dry Matter ◽  
Nitrogen Transfer ◽  
Apparent Difference ◽  
Plant Materials ◽  
Carbon And Nitrogen ◽  
Vesicular Arbuscular ◽  
Normal Atmospheric Pressure ◽  
Mycorrhizal Plants ◽  
The Difference ◽  
Microbial Systems

A two-compartment growth chamber in which the aboveground plant materials were exposed to 14CO2 and the belowground portion was exposed to 15N2 under normal atmospheric pressure was designed for carbon and nitrogen transfer studies. Vicia faba infected with vesicular-arbuscular fungus Glomus mossae and non-mycorrhizal plants fixed similar quantities of N2 at an age of 6½ wk. Approximately 0.10 mg N was fixed∙g−1 dry plant materials∙day−1 and 40 mg C∙g−1 dry matter day−1 were synthesized by mycorrhizal and non-mycorrhizal fababeans during 48 h exposure to 14CO2 at 6½ wk with no apparent difference in yield of dry matter. The non-mycorrhizal plants transferred 37% of the fixed 14C beneath ground. The mycorrhizal ones transferred 47% of the fixed 14C beneath ground. Most of the difference could be accounted for in the belowground respiration. The 14CO2 produced by root-microbial systems of the mycorrhizal fababeans was twice as great as that of the nonmycorrhizal; both contained active rhizobium.

Some Relations of Land Drainage, Nutrients, Particulate Material, and Fish Catch in Two Eastern Canadian Bays

1972 ◽  
Vol 29 (4) ◽  
pp. 357-362 ◽  
Author(s):  
W. H. Sutcliffe Jr.
Keyword(s):  
Particulate Material ◽  
Important Species ◽  
Carbon And Nitrogen ◽  
Land Drainage ◽  
Suspended Particulate ◽  
Suspended Particulate Material ◽  
Fish Catch ◽  
Commercially Important ◽  
Positive Correlations ◽  
Carbon And Nitrogen Content

A year's record of the carbon content of living and of carbon and nitrogen content of nonliving suspended particulate material from St. Margaret's Bay, Nova Scotia, is presented. From considerations of carbon/nitrogen ratios and nutrient data from other sources, the nitrogen budget is briefly considered. The possible importance of land drainage into the bay leads to some positive correlations between runoff and catch of four commercially important species in the Gulf of St. Lawrence.

scholarly journals Tracking the carbons supplying gluconeogenesis

2020 ◽  
Vol 295 (42) ◽  
pp. 14419-14429
Author(s):  
Ankit M. Shah ◽  
Fredric E. Wondisford
Keyword(s):  
Diabetes Mellitus ◽  
Type 2 Diabetes ◽  
Carbon Flux ◽  
Glucose Production ◽  
Comprehensive Analysis ◽  
Major Contributor ◽  
Isotope Tracer ◽  
Novel Targets ◽  
Tracer Experiments

As the burden of type 2 diabetes mellitus (T2DM) grows in the 21st century, the need to understand glucose metabolism heightens. Increased gluconeogenesis is a major contributor to the hyperglycemia seen in T2DM. Isotope tracer experiments in humans and animals over several decades have offered insights into gluconeogenesis under euglycemic and diabetic conditions. This review focuses on the current understanding of carbon flux in gluconeogenesis, including substrate contribution of various gluconeogenic precursors to glucose production. Alterations of gluconeogenic metabolites and fluxes in T2DM are discussed. We also highlight ongoing knowledge gaps in the literature that require further investigation. A comprehensive analysis of gluconeogenesis may enable a better understanding of T2DM pathophysiology and identification of novel targets for treating hyperglycemia.

scholarly journals Availability of carbon and nitrogen in soil affects Metarhizium robertsii root colonization and transfer of insect-derived nitrogen

2019 ◽  
Vol 95 (10) ◽  
Author(s):  
Larissa Barelli ◽  
Scott W Behie ◽  
Michael J Bidochka
Keyword(s):  
Ammonium Nitrate ◽  
Root Colonization ◽  
Pathogenic Fungus ◽  
Broth Culture ◽  
Nitrogen Transfer ◽  
Symbiotic Association ◽  
Metarhizium Robertsii ◽  
Carbon And Nitrogen ◽  
Ecological Importance ◽  
Fungal Gene Expression

ABSTRACT The endophytic, insect pathogenic fungus, Metarhizium, exchanges insect-derived nitrogen for photosynthate as part of a symbiotic association similar to well-known mycorrhizal relationships. However, little is known about this nitrogen transfer in soils where there is an abundance of nitrogen and/or carbon. Here, we applied D-glucose and ammonium nitrate to soil to examine the effect on root colonization and transfer of labelled nitrogen (15N) from an insect (injected with 15N-ammonium sulfate) to Metarhizium robertsii, into leaves of the common bean, Phaseolus vulgaris, over the course of 28 days. Application of exogenous carbon and/or nitrogen to soils significantly reduced detectable 15N in plant leaves. Metarhizium root colonization, quantified with real-time PCR, revealed colonization persisted under all conditions but was significantly greater on roots in soil supplemented with glucose and significantly lower in soil supplemented with ammonium nitrate. Fungal gene expression analysis revealed differential expression of sugar and nitrogen transporters (mrt, st3, nrr1, nit1, mep2) when Metarhizium was grown in pure broth culture or in co-culture with plant roots under various carbon and nitrogen conditions. The observation that Metarhizium maintained root colonization in the absence of nitrogen transfer, and without evidence of plant harm, is intriguing and indicates additional benefits with ecological importance.

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