scholarly journals Voltage-Dependent Cation Channels Permeable to NH4+, K+, and Ca2+ in the Symbiosome Membrane of the Model Legume Lotus japonicus

2002 ◽  
Vol 128 (2) ◽  
pp. 370-378 ◽  
Author(s):  
Daniel M. Roberts ◽  
Stephen D. Tyerman
Keyword(s):  
Lotus Japonicus ◽  
Cation Channels ◽  
Model Legume ◽  
Symbiosome Membrane ◽  
Voltage Dependent

scholarly journals Characterization and Expression Analysis of Genes Encoding Phosphoenolpyruvate Carboxylase and Phosphoenolpyruvate Carboxylase Kinase of Lotus japonicus, a Model Legume

2003 ◽  
Vol 16 (4) ◽  
pp. 281-288 ◽  
Author(s):  
Tomomi Nakagawa ◽  
Tomoko Izumi ◽  
Mari Banba ◽  
Yosuke Umehara ◽  
Hiroshi Kouchi ◽  
...  
Keyword(s):  
Phosphoenolpyruvate Carboxylase ◽  
Root Nodules ◽  
Expression Patterns ◽  
Phosphorylation Site ◽  
Lotus Japonicus ◽  
Specific Protein ◽  
Mrna Levels ◽  
Model Legume ◽  
Putative Phosphorylation Site

Phosphoenolpyruvate carboxylases (PEPCs), one form of which in each legume species plays a central role in the carbon metabolism in symbiotic root nodules, are activated through phosphorylation of a conserved residue by a specific protein kinase (PEPC-PK). We characterized the cDNAs for two PEPC isoforms of Lotus japonicus, an amide-translocating legume that forms determinate nodules. One gene encodes a nodule-enhanced form, which is more closely related to the PEPCs in amide-type indeterminate nodules than those in ureide-type determinate nodules. The other gene is expressed in shoots and roots at a low level. Both forms have the putative phosphorylation site, Ser11. We also isolated a cDNA and the corresponding genomic DNA for PEPC-PK of L. japonicus. The recombinant PEPC-PK protein expressed in Escherichia coli phosphorylated recombinant maize C4-form PEPC efficiently in vitro. The level of mRNA for PEPC-PK was high in root nodules, and those in shoots and roots were also significant. In situ hybridization revealed that the expression patterns of the transcripts for PEPC and PEPC-PK were similar in mature root nodules, but were different in emerging nodules. When L. japonicus seedlings were subjected to prolonged darkness and subsequent illumination, the activity of PEPC-PK and the mRNA levels of both PEPC and PEPC-PK in nodules decreased and then recovered, suggesting that they are regulated according to the amounts of photosynthates transported from shoots.

scholarly journals Αναπρογραμματισμός του μεταβολισμού του Lotus japonicus σε μεταγραφικό, βιοχημικό και μεταβολομικό επίπεδο κατά τη συμβιωτική αζωτοδέσμευση

2016 ◽  
Author(s):  
Χρυσάνθη Καλλονιάτη
Keyword(s):  
Nitrogen Fixation ◽  
Metabolite Profiling ◽  
Symbiotic Nitrogen Fixation ◽  
Sulfur Metabolism ◽  
Lotus Japonicus ◽  
Nitrogen Fixing ◽  
Model Legume ◽  
Whole Plant ◽  
Plant Level ◽  
Molecular And Biochemical Mechanisms

Symbiotic nitrogen fixation in legumes takes place in specialized organs called nodules,which become the main source of assimilated nitrogen for the whole plant. Symbiotic nitro‐gen fixation requires exquisite integration of plant and bacterial metabolism and involvesglobal changes in gene expression and metabolite accumulation in both rhizobia and thehost plant. In order to study the metabolic changes mediated by symbiotic nitrogen fixationon a whole‐plant level, metabolite levels were profiled by gas chromatography–mass spec‐trometry in nodules and non‐symbiotic organs of Lotus japonicus plants uninoculated or in‐oculated with M. loti wt,  ΔnifA or  ΔnifH fix‐ strains. Furthermore, transcriptomic andbiochemical approaches were combined to study sulfur metabolism in nodules, its link tosymbiotic nitrogen fixation, and the effect of nodules on whole‐plant sulfur partitioning andmetabolism. It is well established that nitrogen and sulfur (S) metabolism are tightly en‐twined and sulfur is required for symbiotic nitrogen fixation, however, little is known aboutthe molecular and biochemical mechanisms governing sulfur uptake and assimilation duringsymbiotic nitrogen fixation. Transcript profiling in Lotus japonicus was combined with quan‐tification of S‐metabolite contents and APR activity in nodules and in non‐symbiotic organsof plants uninoculated or inoculated with M. loti wt, ΔnifA or ΔnifH fix‐ strains. Moreover,sulfate uptake and its distribution into different plant organs were analyzed and 35S‐flux intodifferent S‐pools was monitored. Metabolite profiling revealed that symbiotic nitrogen fixa‐tion results in dramatic changes of many aspects of primary and secondary metabolism innodules which leads to global reprogramming of metabolism of the model legume on awhole‐plant level. Moreover, our data revealed that nitrogen fixing nodules represent athiol‐rich organ. Their high APR activity and 35S‐flux into cysteine and its metabolites in com‐bination with the transcriptional up‐regulation of several genes involved in sulfur assimila‐tion highlight the function of nodules as a new site of sulfur assimilation. The higher thiolcontent observed in non‐symbiotic organs of nitrogen fixing plants in comparison touninoculated plants cannot be attributed to local biosynthesis, indicating that nodules couldserve as a novel source of reduced sulfur for the plant, which triggers whole‐plant repro‐gramming of sulfur metabolism. Interestingly, the changes in metabolite profiling and theenhanced thiol biosynthesis in nodules and their impact on the whole‐plant sulfur, carbonand nitrogen economy are dampened in fix‐ plants, which in most respects metabolically re‐sembled uninoculated plants, indicating a strong interaction between nitrogen fixation andsulfur and carbon metabolism.

Recent Advances in the Molecular Genetics of The Model Legume Lotus japonicus

1997 ◽  
pp. 255-258
Author(s):  
Leif Schauser ◽  
Leszek Boron ◽  
Eloisa Pajuelo ◽  
Thomas Thykjær ◽  
Dorthe Danielsen ◽  
...  
Keyword(s):  
Molecular Genetics ◽  
Lotus Japonicus ◽  
Model Legume ◽  
Recent Advances

Uterine Excitability and Ion Channels and Their Changes with Gestation and Hormonal Environment

2020 ◽  
Vol 83 (1) ◽  
Author(s):  
Susan Wray ◽  
Sarah Arrowsmith
Keyword(s):  
Ion Channels ◽  
Inward Rectifier ◽  
Cation Channels ◽  
Annual Review ◽  
Publication Date ◽  
K Channels ◽  
Voltage Gated ◽  
New Findings ◽  
Voltage Dependent ◽  
Pore Domain

We address advances in the understanding of myometrial physiology, focusing on excitation and the effects of gestation on ion channels and their relevance to labor. This review moves through pioneering studies to exciting new findings. We begin with the myometrium and its myocytes and describe how excitation might initiate and spread in this myogenic smooth muscle. We then review each of the ion channels in the myometrium: L- and T-type Ca2+ channels, KATP (Kir6) channels, voltage-dependent K channels (Kv4, Kv7, and Kv11), twin-pore domain K channels (TASK, TREK), inward rectifier Kir7.1, Ca2+-activated K+ channels with large (KCNMA1, Slo1), small (KCNN1–3), and intermediate (KCNN4) conductance, Na-activated K channels (Slo2), voltage-gated (SCN) Na+ and Na+ leak channels, nonselective (NALCN) channels, the Na K-ATPase, and hyperpolarization-activated cation channels. We finish by assessing how three key hormones— oxytocin, estrogen, and progesterone—modulate and integrate excitability throughout gestation. Expected final online publication date for the Annual Review of Physiology, Volume 83 is February 10, 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

scholarly journals Flavonoids and Isoflavonoids Biosynthesis in the Model Legume Lotus japonicus; Connections to Nitrogen Metabolism and Photorespiration

Plants ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 774 ◽  
Author(s):  
Margarita García-Calderón ◽  
Carmen M. Pérez-Delgado ◽  
Peter Palove-Balang ◽  
Marco Betti ◽  
Antonio J. Márquez
Keyword(s):  
Abiotic Stress ◽  
Nitrogen Metabolism ◽  
Lotus Japonicus ◽  
Regulatory Proteins ◽  
Phenylpropanoid Metabolism ◽  
Biological Processes ◽  
Model Legume ◽  
Different Types ◽  
Made In

Phenylpropanoid metabolism represents an important metabolic pathway from which originates a wide number of secondary metabolites derived from phenylalanine or tyrosine, such as flavonoids and isoflavonoids, crucial molecules in plants implicated in a large number of biological processes. Therefore, various types of interconnection exist between different aspects of nitrogen metabolism and the biosynthesis of these compounds. For legumes, flavonoids and isoflavonoids are postulated to play pivotal roles in adaptation to their biological environments, both as defensive compounds (phytoalexins) and as chemical signals in symbiotic nitrogen fixation with rhizobia. In this paper, we summarize the recent progress made in the characterization of flavonoid and isoflavonoid biosynthetic pathways in the model legume Lotus japonicus (Regel) Larsen under different abiotic stress situations, such as drought, the impairment of photorespiration and UV-B irradiation. Emphasis is placed on results obtained using photorespiratory mutants deficient in glutamine synthetase. The results provide different types of evidence showing that an enhancement of isoflavonoid compared to standard flavonol metabolism frequently occurs in Lotus under abiotic stress conditions. The advance produced in the analysis of isoflavonoid regulatory proteins by the use of co-expression networks, particularly MYB transcription factors, is also described. The results obtained in Lotus japonicus plants can be also extrapolated to other cultivated legume species, such as soybean, of extraordinary agronomic importance with a high impact in feeding, oil production and human health.

Hormone-induced rise in cytosolic Ca2+ in axolotl hepatocytes: properties of the Ca2+ influx channel

1997 ◽  
Vol 273 (5) ◽  
pp. C1526-C1532 ◽  
Author(s):  
Thomas Lenz ◽  
Jochen W. Kleineke
Keyword(s):  
Inhibitory Concentration ◽  
Cation Channels ◽  
Strong Inhibition ◽  
Michaelis Constant ◽  
Cyclic Monophosphate ◽  
First Order ◽  
First Order Kinetics ◽  
Nonselective Cation Channels ◽  
Store Depletion ◽  
Voltage Dependent

Calcium entry in nonexcitable cells occurs through Ca2+-selective channels activated secondarily to store depletion and/or through receptor- or second messenger-operated channels. In amphibian liver, hormones that stimulate the production of adenosine 3′,5′-cyclic monophosphate (cAMP) also regulate the opening of an ion gate in the plasma membrane, which allows a noncapacitative inflow of Ca2+. To characterize this Ca2+ channel, we studied the effects of inhibitors of voltage-dependent Ca2+ channels and of nonselective cation channels on 8-bromoadenosine 3′,5′-cyclic monophosphate (8-BrcAMP)-dependent Ca2+ entry in single axolotl hepatocytes. Ca2+ entry provoked by 8-BrcAMP in the presence of physiological Ca2+ followed first-order kinetics (apparent Michaelis constant = 43 μM at the cell surface). Maximal values of cytosolic Ca2+ (increment ∼300%) were reached within 15 s, and the effect was transient (half time of 56 s). We report a strong inhibition of cAMP-dependent Ca2+ entry by nifedipine [half-maximal inhibitory concentration (IC50) = 0.8 μM], by verapamil (IC50 = 22 μM), and by SK&F-96365 (IC50 = 1.8 μM). Depolarizing concentrations of K+were without effect. Gadolinium and the anti-inflammatory compound niflumate, both inhibitors of nonselective cation channels, suppressed Ca2+ influx. This “profile” indicates a novel mechanism of Ca2+ entry in nonexcitable cells.

Identification of tissue-specific gene clusters and orthologues of nodulation-related genes in Vigna angularis

2014 ◽  
Vol 12 (S1) ◽  
pp. S21-S26 ◽  
Author(s):  
Yang Jae Kang ◽  
Jayern Lee ◽  
Yong Hwan Kim ◽  
Suk-Ha Lee
Keyword(s):  
De Novo ◽  
Transcriptome Assembly ◽  
Lotus Japonicus ◽  
Gene Clusters ◽  
Specific Gene ◽  
Vigna Angularis ◽  
Model Legume ◽  
Tissue Specific ◽  
Autoregulation Of Nodulation ◽  
Species Specific

Nitrogen fixation in legumes is an important agricultural trait that results from symbiosis between the root and rhizobia. To understand the molecular basis of nodulation, recent research has been focused on the identification of nodulation-related genes by functional analysis using two major model legumes, Medicago truncatula and Lotus japonicus. Thus far, three important processes have been discovered, namely Nod factor (NF) perception, NF signalling and autoregulation of nodulation. Nevertheless, application of the results of these studies is limited for non-model legume crops because a reference genome is unavailable. However, because the cost of whole-transcriptome analysis has dropped dramatically due to the Next generation sequencer (NGS) technology, minor crops for which reference sequences are yet to be constructed can still be studied at the genome level. In this study, we sequenced the leaf and root transcriptomes of Vigna angularis (accession IT213134) and de novo assembled. Our results demonstrate the feasibility of using the transcriptome assembly to effectively identify tissue-specific peptide clusters related to tissue-specific functions and species-specific nodulation-related genes.

scholarly journals Molecular Analysis of the Pathway for the Synthesis of Thiol Tripeptides in the Model Legume Lotus japonicus

2003 ◽  
Vol 16 (11) ◽  
pp. 1039-1046 ◽  
Author(s):  
Manuel A. Matamoros ◽  
Maria R. Clemente ◽  
Shusei Sato ◽  
Erika Asamizu ◽  
Satoshi Tabata ◽  
...  
Keyword(s):  
Lotus Japonicus ◽  
Regulatory Elements ◽  
Chromosome 1 ◽  
Glutathione Synthetase ◽  
Promoter Regions ◽  
Model Legume ◽  
Cis Acting ◽  
Glutamylcysteine Synthetase ◽  
Exon 1 ◽  
Legume Symbiosis

The thiol tripeptides, glutathione (GSH) and homoglu-tathione (hGSH), perform multiple roles in legumes, including protection against toxicity of free radicals and heavy metals. The three genes involved in the synthesis of GSH and hGSH in the model legume, Lotus japonicus, have been fully characterized and appear to be present as single copies in the genome. The γ-glutamylcysteine synthetase (γecs) gene was mapped on the long arm of chromosome 4 (70.0 centimorgans [cM]) and consists of 15 exons, whereas the glutathione synthetase (gshs) and homoglutathione synthetase (hgshs) genes were mapped on the long arm of chromosome 1 (81.3 cM) and found to be arranged in tandem with a separation of approximately 8 kb. Both genes consist of 12 exons of exactly the same size (except exon 1, which is similar). Two types of transcripts were detected for the gshs gene, which putatively encode proteins localized in the plastids and cytosol. Promoter regions contain cis-acting regulatory elements that may be involved in the plant's response to light, hormones, and stress. Determination of transcript levels, enzyme activities, and thiol contents in nodules, roots, and leaves revealed that γecs and hgshs are expressed in all three plant organs, whereas gshs is significantly functional only in nodules. This strongly suggests an important role of GSH in the rhizobia-legume symbiosis.

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