scholarly journals Defense Priming in Nicotiana tabacum Accelerates and Amplifies ‘New’ C/N Fluxes in Key Amino Acid Biosynthetic Pathways

Plants ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 851
Author(s):  
Nils Hanik ◽  
Marcel Best ◽  
Michael J. Schueller ◽  
Ryan Tappero ◽  
Richard A. Ferrieri
Keyword(s):  
Nicotiana Tabacum ◽  
Metal Ion ◽  
Enzyme Regulation ◽  
Shikimate Pathway ◽  
Fixed Carbon ◽  
Ion Regulation ◽  
Defense Priming ◽  
Multiple Strategies ◽  
N Utilization ◽  
N Fluxes

In the struggle to survive herbivory by leaf-feeding insects, plants employ multiple strategies to defend themselves. One mechanism by which plants increase resistance is by intensifying their responsiveness in the production of certain defense agents to create a rapid response. Known as defense priming, this action can accelerate and amplify responses of metabolic pathways, providing plants with long-lasting resistance, especially when faced with waves of attack. In the work presented, short-lived radiotracers of carbon administered as 11CO2 and nitrogen administered as 13NH3 were applied in Nicotiana tabacum, to examine the temporal changes in ‘new’ C/N utilization in the biosynthesis of key amino acids (AAs). Responses were induced by using topical application of the defense hormone jasmonic acid (JA). After a single treatment, metabolic partitioning of recently fixed carbon (designated ‘new’ carbon and reflected as 11C) increased through the shikimate pathway, giving rise to tyrosine, phenylalanine and tryptophan. Amplification in ‘new’ carbon fluxes preceded changes in the endogenous (12C) pools of these AAs. Testing after serial JA treatments revealed that fluxes of ‘new’ carbon were accelerated, amplified and sustained over time at this higher rate, suggesting a priming effect. Similar results were observed with recently assimilated nitrogen (designated ‘new’ nitrogen reflected as 13N) with its partitioning into serine, glycine and glutamine, which play important roles supporting the shikimate pathway and downstream secondary metabolism. Finally, X-ray fluorescence imaging revealed that levels of the element Mn, an important co-factor for enzyme regulation in the shikimate pathway, increased within JA treated tissues, suggesting a link between plant metal ion regulation and C/N metabolic priming.

Integrating naive Bayes models and external knowledge to examine copper and iron homeostasis in S. cerevisiae

2000 ◽  
Vol 4 (2) ◽  
pp. 127-135 ◽  
Author(s):  
E. J. Moler ◽  
D. C. Radisky ◽  
I. S. Mian
Keyword(s):  
Cell Cycle ◽  
Transcription Factors ◽  
Metal Ion ◽  
Iron Homeostasis ◽  
Graphical Model ◽  
Naive Bayes ◽  
Naïve Bayes ◽  
Diauxic Shift ◽  
Ion Regulation ◽  
External Knowledge

A novel suite of analytical techniques and visualization tools are applied to 78 published transcription profiling experiments monitoring 5,687 Saccharomyces cerevisiae genes in studies examining cell cycle, responses to stress, and diauxic shift. A naive Bayes model discovered and characterized 45 classes of gene profile vectors. An enrichment measure quantified the association between these classes and specific external knowledge defined by four sets of categories to which genes can be assigned: 106 protein functions, 5 stages of the cell cycle, 265 transcription factors, and 16 chromosomal locations. Many of the 38 genes in class 42 are known to play roles in copper and iron homeostasis. The 17 uncharacterized open reading frames in this class may be involved in similar homeostatic processes; human homologs of two of them could be associated with as yet undefined disease states arising from aberrant metal ion regulation. The Met4, Met31, and Met32 transcription factors may play a role in coregulating genes involved in copper and iron metabolism. Extensions of the simple graphical model used for clustering to learning more complex models of genetic networks are discussed.

scholarly journals Enzymes of heme metabolism is the kidney. Regulation by trace metals which do not form heme complexes

1977 ◽  
Vol 146 (5) ◽  
pp. 1286-1293 ◽  
Author(s):  
MD Maines ◽  
A Kappas
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Early Period ◽  
Reciprocal Relationship ◽  
Central Metal ◽  
Ion Regulation ◽  
Heme Metabolism ◽  
Rate Limiting

The in vivo regulation by metal ions of the enzymes of heme metabolism in kidney-particularly of ALAS, the rate-limiting enzyme in heine formation- was investigated. Ni(2+) and Pt(4+), metals which do not enzymatically form metalloporphyrins, were found to regulate ALAS in kidney as they do in liver. The pattern of this regulation was generally similar to that observed with heme and metal ions in liver, i.e., a late increase in enzyme activity after an early period in which ALAS activity was unaltered or inhibited. The metals did not interact with the enzyme in vitro to alter its activity. In this study no direct reciprocal relationship between ALAS activity and total cellular heine content was demonstrated. The metal ions, particularly Pt(4+), also altered the activity of other enzymes of heme biosynthesis in kidney. Pt(4+) severely inhibited the activity of ALAD and UROS. Ni(2+) and Pt(4+) were potent inducers of heme oxygenase, the initial and rate-limiting enzyme in heine degradation. It is proposed that the physiological regulation of ALAS is mediated through the action of metal ions, rather than by the cellular content of heine, and that the regulation of ALAS by heine reflects the action of the central metal ion of heme rather than that of the entire metalloporphyrin complex. In this proposed mechanism for metal ion regulation of ALAS, the tetrapyrrole moiety of heine is considered to function principally as an efficient carrier of metal to the regulatory site for ALAS production, inasmuch as the tetrapyrrole ring itself has been shown in earlier studies not to have any effect on ALAS activity. The production of heine oxygenase is believed to be similarly regulated.

Postprandial intestinal and whole body nitrogen kinetics and distribution in piglets fed a single meal

2005 ◽  
Vol 288 (2) ◽  
pp. E436-E446 ◽  
Author(s):  
Cécile Bos ◽  
Barbara Stoll ◽  
Hélène Fouillet ◽  
Claire Gaudichon ◽  
Xinfu Guan ◽  
...  
Keyword(s):  
High Efficiency ◽  
Peripheral Zone ◽  
Whole Body ◽  
Postprandial Period ◽  
Young Pigs ◽  
N Utilization ◽  
N Release ◽  
N Fluxes ◽  
Single Meal ◽  
Meal Ingestion

Our aim was to characterize the postprandial total and dietary N fluxes in the portal drained viscera (PDV) and whole body after administration of a single meal in young pigs. Seven 4-wk-old piglets, implanted with a portal flow probe and portal, arterial and venous catheters, received a primed constant [18O]urea intravenous infusion and were studied for 8 h after a bolus mixed meal ingestion (46 mmol N/kg body wt) intrinsically labeled with 15N to trace dietary N fluxes. The real cecal digestibility of the formula was 94.3% (SD 1.8). PDV output of dietary N was found principally in the pool of circulating protein (51% of the measured dietary N PDV output), in the free α-amino N pool (44%), and to a lesser extent in ammonia (5%). Dietary N release in α-amino N and ammonia mainly occurred during the first 3 h. Total and exogenous postprandial urea productions were 5.8 and 2.0 mmol N/kg body wt, respectively. At the end of the postprandial period, losses of dietary N amounted to 10.3% of the dose: 5.7% through ileal losses and 4.6% by deamination and transfer to urea. Net postprandial retention of dietary N was 90.4% (SD 1.3), of which 20% was found in splanchnic zone (small intestine 10%, liver 5%, and plasma protein 3%) and 42% in peripheral zone (muscle 31%, skin 6%). In conclusion, our results show a high efficiency of dietary N utilization for muscular uptake and anabolic utilization. However, the results obtained point out the necessity to further explore the form of dietary N released into the portal blood.

scholarly journals Histoplasma Responses to Nutritional Immunity Imposed by Macrophage Activation

2019 ◽  
Vol 5 (2) ◽  
pp. 45 ◽  
Author(s):  
Peter J. Brechting ◽  
Chad A. Rappleye
Keyword(s):  
Metal Ion ◽  
Macrophage Activation ◽  
Histoplasma Capsulatum ◽  
Host Cells ◽  
Phagocytic Cells ◽  
Gm Csf ◽  
Multiple Strategies ◽  
Nutritional Immunity ◽  
Cytokine Activation ◽  
Ifn Γ

The fungal pathogen Histoplasma capsulatum resides within the phagosome of host phagocytic cells. Within this intracellular compartment, Histoplasma yeast replication requires the acquisition of several essential nutrients, including metal ions. Recent work has shown that while iron, zinc, and copper are sufficiently abundant in resting macrophages, cytokine activation of these host cells causes restriction of these metals from intracellular yeasts as a form of nutritional immunity. Faced with limited iron availability in the phagosome following macrophage activation by IFN-γ, Histoplasma yeasts secrete iron-scavenging siderophores and employ multiple strategies for reduction of ferric iron to the more physiologically useful ferrous form. IFN-γ activation of macrophages also limits availability of copper in the phagosome, forcing Histoplasma reliance on the high affinity Ctr3 copper importer for copper acquisition. GM-CSF activation stimulates macrophage production of zinc-chelating metallothioneins and zinc transporters to sequester zinc from Histoplasma yeasts. In response, Histoplasma yeasts express the Zrt2 zinc importer. These findings highlight the dynamics of phagosomal metal ion concentrations in host-pathogen interactions and explain one mechanism by which macrophages become a less permissive environment for Histoplasma replication with the onset of adaptive immunity.

Metal-ion regulation of gene expression in yeast

1998 ◽  
Vol 2 (2) ◽  
pp. 216-221 ◽  
Author(s):  
Dennis R Winge ◽  
Laran T Jensen ◽  
Chandra Srinivasan
Keyword(s):  
Gene Expression ◽  
Metal Ion ◽  
Regulation Of Gene Expression ◽  
Ion Regulation

scholarly journals Heavy Metal Ion Regulation of Gene Expression

2015 ◽  
Vol 290 (29) ◽  
pp. 18216-18226 ◽  
Author(s):  
Eric E. Beier ◽  
Tzong-jen Sheu ◽  
Deborah Dang ◽  
Jonathan D. Holz ◽  
Resika Ubayawardena ◽  
...  
Keyword(s):  
Gene Expression ◽  
Heavy Metal ◽  
Metal Ion ◽  
Regulation Of Gene Expression ◽  
Heavy Metal Ion ◽  
Ion Regulation

Metal ion regulation of gene expression

1988 ◽  
Vol 203 (4) ◽  
pp. 875-884 ◽  
Author(s):  
Victor De Lorenzo ◽  
Fabio Giovannini ◽  
Marta Herrero ◽  
J.B. Neilands
Keyword(s):  
Gene Expression ◽  
Metal Ion ◽  
Regulation Of Gene Expression ◽  
Ion Regulation

Aspects of high-resolution imaging with a scanning ion microprobe

1986 ◽  
Vol 44 ◽  
pp. 750-751
Author(s):  
R. Levi-Setti ◽  
J. M. Chabala ◽  
Y. L. Wang
Keyword(s):  
Metal Ion ◽  
Secondary Ion Mass Spectrometry ◽  
Chromatic Aberration ◽  
Ion Source ◽  
Ion Microprobe ◽  
Emission Pattern ◽  
Intrinsic Resolution ◽  
Resolution Imaging ◽  
20 Nm ◽  
Secondary Ion

We have shown the feasibility of 20 nm lateral resolution in both topographic and elemental imaging using probes of this size from a liquid metal ion source (LMIS) scanning ion microprobe (SIM). This performance, which approaches the intrinsic resolution limits of secondary ion mass spectrometry (SIMS), was attained by limiting the size of the beam defining aperture (5μm) to subtend a semiangle at the source of 0.16 mr. The ensuing probe current, in our chromatic-aberration limited optical system, was 1.6 pA with Ga+ or In+ sources. Although unique applications of such low current probes have been demonstrated,) the stringent alignment requirements which they imposed made their routine use impractical. For instance, the occasional tendency of the LMIS to shift its emission pattern caused severe misalignment problems.

Tobacco Mosaic Virus-Infected Tissue

1985 ◽  
Vol 43 ◽  
pp. 510-511
Author(s):  
Egbert W. Henry
Keyword(s):  
Nicotiana Tabacum ◽  
Tobacco Mosaic Virus ◽  
Chlorogenic Acid ◽  
Mosaic Virus ◽  
Host Resistance ◽  
Oxidative Metabolism ◽  
Leaf Tissue ◽  
Vein Clearing ◽  
Basal Septum ◽  
Concentration Levels

Tobacco mosaic virus (TMV) infection has been studied in several investigations of Nicotiana tabacum leaf tissue. Earlier studies have suggested that TMV infection does not have precise infective selectivity vs. specific types of tissues. Also, such tissue conditions as vein banding, vein clearing, liquification and suberization may result from causes other than direct TMV infection. At the present time, it is thought that the plasmodesmata, ectodesmata and perhaps the plasmodesmata of the basal septum may represent the actual or more precise sites of TMV infection.TMV infection has been implicated in elevated levels of oxidative metabolism; also, TMV infection may have a major role in host resistance vs. concentration levels of phenolic-type enzymes. Therefore, enzymes such as polyphenol oxidase, peroxidase and phenylalamine ammonia-lyase may show an increase in activity in response to TMV infection. It has been reported that TMV infection may cause a decrease in o-dihydric phenols (chlorogenic acid) in some tissues.

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