Silicon‐mediated manganese tolerance of cucumber: the apoplastic modulation

Mapping Intimacies ◽

10.5194/egusphere-egu21-10994 ◽

2021 ◽

Author(s):

Jelena Dragisic Maksimovic ◽

Milos Mojovic ◽

Vuk Maksimovic

Keyword(s):

Cell Walls ◽

Relative Proportion ◽

Control Treatment ◽

Binding Potential ◽

Wall Structure ◽

Relative Distribution ◽

Mn Toxicity ◽

Leaf Apoplast ◽

Si Supply

An impressive body of Si research could be found in the literature despite the fact that, from a biochemical perspective, Si is a &#8220;monotonous&#8221; element largely uncharged and unreactive at physiological pH (forming mostly silicates and SiO2 polymers). However, the detailed role of Si in plants remains unexploited, particularly the potential for its practical application. One of the main properties of Si intensively explored is the protection mechanism(s) against biotic and abiotic stresses, especially heavy metal stress. To investigate the effect of Si application on the Mn binding potential of the leaf apoplast, cucumber plants were grown in nutrient solutions with optimal (0.5 &#181;M) or excessive (100 &#181;M) Mn concentrations with or without Si supply to roots. Leaves were subjected to fractionated extraction of Mn revealing a relative distribution of Mn fractions in cucumber leaves: water-extractable (WE) Mn represents the soluble fraction in the cell walls; the protein-bound (PB) Mn fraction originates mostly from the symplast; while the cell wall-bound (CWB) Mn fraction represents Mn which is fixed to the wall structure. After the high Mn supply (100 &#181;M), the concentration of WE Mn was 10-fold higher compared to control, while the relative proportion of the WE Mn fraction decreased from 56% in control to 23% in high Mn treatment. Si application did not affect WE and PB Mn fractions in the control treatment but significantly decreased these fractions in the high Mn treatment. On the other hand, the CWB Mn significantly increased in the leaves of Si-fed plants. Data obtained by fractionated Mn extraction are consistent with the relative proportion of free and bound Mn, estimated from the recorded electron paramagnetic resonance (EPR) signals of Mn2+. The EPR spectrum of a high spin Mn2+ showed the characteristic six hyperfine lines whose intensity correlated with Mn treatments and, consequently, leaf concentrations of Mn. The results presented here demonstrated that Si supply increased the Mn binding properties of leaf cell walls in cucumber plants with simultaneously decreasing of the free apoplastic Mn2+, indicating the protective role of Si in smothering harmful (inter)actions of free Mn2+ within plant tissue. Taken together, the leaf apoplast plays the central role in modulation of Mn toxicity and Si enhanced Mn tolerance in cucumber.This work was supported by the Ministry of Education, Science and Technological Development of the Republic of Serbia (Contract No. 451-03-68/2020-14/200053).

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Role of streptomycin in the life of Streptomyces griseus: streptidine-containing fractions in the cell walls of Streptomyces griseus strains

Canadian Journal of Microbiology ◽

10.1139/m68-222 ◽

1968 ◽

Vol 14 (12) ◽

pp. 1325-1331 ◽

Cited By ~ 8

Author(s):

Gy. Barabás ◽

G. Szabó

Keyword(s):

Cell Wall ◽

Cell Walls ◽

Streptomyces Griseus ◽

Cell Wall Structure ◽

Wall Structure

Streptidine was isolated from the cell wall and mycelia of a Streptomyces griseus strain that did not produce streptomycin. Streptidine probably exists as a complex with arginine and other Sakaguchi- and ninhydrin-positive compounds. Hydrolyzing these compounds with 6 N HCl for 20 hours released streptidine, arginine, threonine, serine, and alanine. A method is presented for the separation of streptidine from arginine.Streptidine was also found in the cell wall of a streptomycin-producing S. griseus strain. These facts support a hypothesis that streptidine plays a role in the cell wall structure of S. griseus.

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Exploration of cell wall architecture with the rapid-freeze deep-etch technique

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100146485 ◽

1993 ◽

Vol 51 ◽

pp. 128-129

Author(s):

Béatrice Satiat-Jeunemaitre ◽

Chris Hawes

Keyword(s):

Plant Cell ◽

Cell Walls ◽

Cell Biology ◽

Molecular Model ◽

Three Dimensional ◽

Secretory Activity ◽

Wall Structure ◽

Specimen Preparation ◽

Molecular Architecture ◽

Plant Cell Walls

The comprehension of the molecular architecture of plant cell walls is one of the best examples in cell biology which illustrates how developments in microscopy have extended the frontiers of a topic. Indeed from the first electron microscope observation of cell walls it has become apparent that our understanding of wall structure has advanced hand in hand with improvements in the technology of specimen preparation for electron microscopy. Cell walls are sub-cellular compartments outside the peripheral plasma membrane, the construction of which depends on a complex cellular biosynthetic and secretory activity (1). They are composed of interwoven polymers, synthesised independently, which together perform a number of varied functions. Biochemical studies have provided us with much data on the varied molecular composition of plant cell walls. However, the detailed intermolecular relationships and the three dimensional arrangement of the polymers in situ remains a mystery. The difficulty in establishing a general molecular model for plant cell walls is also complicated by the vast diversity in wall composition among plant species.

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Quantitative accuracy of serotonergic neurotrans-mission imaging with high-resolution 123I SPECT

Nuklearmedizin ◽

10.1055/s-0038-1623914 ◽

2004 ◽

Vol 43 (06) ◽

pp. 185-189 ◽

Cited By ~ 4

Author(s):

J. T. Kuikka

Keyword(s):

High Resolution ◽

Scatter Correction ◽

Region Of Interest ◽

Binding Potential ◽

Partial Volume ◽

Therapeutic Drugs ◽

Quantitative Accuracy ◽

Critical Error ◽

Statistical Noise

Summary Aim: Serotonin transporter (SERT) imaging can be used to study the role of regional abnormalities of neurotransmitter release in various mental disorders and to study the mechanism of action of therapeutic drugs or drugs’ abuse. We examine the quantitative accuracy and reproducibility that can be achieved with high-resolution SPECT of serotonergic neurotransmission. Method: Binding potential (BP) of 123I labeled tracer specific for midbrain SERT was assessed in 20 healthy persons. The effects of scatter, attenuation, partial volume, mis-registration and statistical noise were estimated using phantom and human studies. Results: Without any correction, BP was underestimated by 73%. The partial volume error was the major component in this underestimation whereas the most critical error for the reproducibility was misplacement of region of interest (ROI). Conclusion: The proper ROI registration, the use of the multiple head gamma camera with transmission based scatter correction introduce more relevant results. However, due to the small dimensions of the midbrain SERT structures and poor spatial resolution of SPECT, the improvement without the partial volume correction is not great enough to restore the estimate of BP to that of the true one.

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Neuronal nitric oxide synthase and systemic vasodilation in rats with cirrhosis

AJP Renal Physiology ◽

10.1152/ajprenal.2000.279.6.f1110 ◽

2000 ◽

Vol 279 (6) ◽

pp. F1110-F1115 ◽

Cited By ~ 50

Author(s):

Lieming Xu ◽

Ethan P. Carter ◽

Mamiko Ohara ◽

Pierre-Yves Martin ◽

Boris Rogachev ◽

...

Keyword(s):

Nitric Oxide ◽

Liver Cirrhosis ◽

Nitric Oxide Synthase ◽

Control Treatment ◽

Sodium Balance ◽

Hyperdynamic Circulation ◽

Molecular Approaches ◽

Advanced Liver Cirrhosis ◽

Oxide Synthase

Cirrhosis is typically associated with a hyperdynamic circulation consisting of low blood pressure, low systemic vascular resistance (SVR), and high cardiac output. We have recently reported that nonspecific inhibition of nitric oxide synthase (NOS) with nitro-l-arginine methyl ester reverses the hyperdynamic circulation in rats with advanced liver cirrhosis induced by carbon tetrachloride (CCl4). Although an important role for endothelial NOS (eNOS) is documented in cirrhosis, the role of neuronal NOS (nNOS) has not been investigated. The present study was carried out to specifically investigate the role of nNOS during liver cirrhosis. Specifically, physiological, biochemical, and molecular approaches were employed to evaluate the contribution of nNOS to the cirrhosis-related hyperdynamic circulation in CCl4-induced cirrhotic rats with ascites. Cirrhotic animals had a significant increase in water and sodium retention. In the aorta from cirrhotic animals, both nNOS protein expression and cGMP concentration were significantly elevated compared with control. Treatment of cirrhotic rats for 7 days with the specific nNOS inhibitor 7-nitroindazole (7-NI) normalized the low SVR and mean arterial pressure, elevated cardiac index, and reversed the positive sodium balance. Increased plasma arginine vasopressin concentrations in the cirrhotic animals were also repressed with 7-NI in association with diminished water retention. The circulatory changes were associated with a reduction in aortic nNOS expression and cGMP. However, 7-NI treatment did not restore renal function in cirrhotic rats (creatinine clearance: 0.76 ± 0.03 ml · min−1· 100 g body wt−1in cirrhotic rats vs. 0.79 ± 0.05 ml · min−1· 100 g body wt−1in cirrhotic rats+7-NI; P NS.). Taken together, these results indicate that nNOS-derived NO contributes to the development of the hyperdynamic circulation and fluid retention in cirrhosis.

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Suppression of personality variation in boldness during foraging in three-spined sticklebacks

Behavioral Ecology and Sociobiology ◽

10.1007/s00265-021-03007-2 ◽

2021 ◽

Vol 75 (4) ◽

Author(s):

Hannah E. A. MacGregor ◽

Aislinn Cottage ◽

Christos C. Ioannou

Keyword(s):

Negative Feedback ◽

Risk Taking ◽

Positive Feedback ◽

Gasterosteus Aculeatus ◽

Control Treatment ◽

Refuge Use ◽

Individual Level ◽

Behavioural Type ◽

State Behaviour

Abstract Consistent inter-individual variation in behaviour within a population, widely referred to as personality variation, can be affected by environmental context. Feedbacks between an individual’s behaviour and state can strengthen (positive feedback) or weaken (negative feedback) individual differences when experiences such as predator encounters or winning contests are dependent on behavioural type. We examined the influence of foraging on individual-level consistency in refuge use (a measure of risk-taking, i.e. boldness) in three-spined sticklebacks, Gasterosteus aculeatus, and particularly whether changes in refuge use depended on boldness measured under control conditions. In the control treatment trials with no food, individuals were repeatable in refuge use across repeated trials, and this behavioural consistency did not differ between the start and end of these trials. In contrast, when food was available, individuals showed a higher degree of consistency in refuge use at the start of the trials versus controls but this consistency significantly reduced by the end of the trials. The effect of the opportunity to forage was dependent on behavioural type, with bolder fish varying more in their refuge use between the start and the end of the feeding trials than shyer fish, and boldness positively predicted the likelihood of feeding at the start but not at the end of the trials. This suggests a state-behaviour feedback, but there was no overall trend in how bolder individuals changed their behaviour. Our study shows that personality variation can be suppressed in foraging contexts and a potential but unpredictable role of feedbacks between state and behaviour. Significance statement In this experimental study, we examined how foraging influences consistency in risk-taking in individual three-spined sticklebacks. We show that bolder individuals become less consistent in their risk-taking behaviour than shyer individuals during foraging. Some bolder individuals reinforce their risk-taking behaviour, suggesting a positive feedback between state and behaviour, while others converge on the behaviour of shyer individuals, suggesting a negative feedback. In support of a role of satiation in driving negative feedback effects, we found that bolder individuals were more likely to feed at the start but not at the end of the trials. Overall, our findings suggest that foraging can influence personality variation in risk-taking behaviour; however, the role of feedbacks may be unpredictable.

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Role of (1,3)(1,4)-β-Glucan in Cell Walls: Interaction with Cellulose

Biomacromolecules ◽

10.1021/bm5001247 ◽

2014 ◽

Vol 15 (5) ◽

pp. 1727-1736 ◽

Cited By ~ 37

Author(s):

Sarah N. Kiemle ◽

Xiao Zhang ◽

Alan R. Esker ◽

Guillermo Toriz ◽

Paul Gatenholm ◽

...

Keyword(s):

Cell Walls

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Etude ultrastructurale des relations hôte–parasite au cours de l'infection des pommes par le Phytophthora cactorum

Canadian Journal of Botany ◽

10.1139/b81-036 ◽

1981 ◽

Vol 59 (2) ◽

pp. 251-263 ◽

Cited By ~ 11

Author(s):

X. Mourichon ◽

G. Sallé

Keyword(s):

Cell Walls ◽

Susceptible Variety ◽

Host Cells ◽

Phytophthora Cactorum ◽

Electron Microscopic ◽

Susceptible Host ◽

Golden Delicious ◽

Extrahaustorial Matrix ◽

Apple Fruits

An electron microscopic study was performed on haustoria of Phytophthora cactorum (L. et C.) Schroeter developed in tissues of two cultivars of apple fruits: a susceptible variety ('Golden delicious') and a resistant one ('Belle de Boskoop'). Ultrastructure of intercellular hyphae and some aspects of their penetration between contiguous host cells were described. A light dissolution of the host cell walls was observed. Ontogenic investigations indicated that in the susceptible host, the wall of the fungal haustoria was covered with a dense-stained extrahaustorial matrix. Its origin and its polysaccharide nature were demonstrated. On the other hand, the resistant host developed, immediately after the inoculation, a papilla which gave rise, later on, to a sheath enclosing adult haustoria. The role of these callosic structures in the phenomenon of resistance was discussed.

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The Transcription Factor Con7-1 Is a Master Regulator of Morphogenesis and Virulence in Fusarium oxysporum

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-07-14-0205-r ◽

2015 ◽

Vol 28 (1) ◽

pp. 55-68 ◽

Cited By ~ 16

Author(s):

Carmen Ruiz-Roldán ◽

Yolanda Pareja-Jaime ◽

José Antonio González-Reyes ◽

M. Isabel G. Roncero

Keyword(s):

Cell Wall ◽

Fusarium Oxysporum ◽

Gene Expression Analysis ◽

Wall Structure ◽

Targeted Deletion ◽

Signal Perception ◽

Cell Wall Biogenesis ◽

Primary And Secondary Metabolism ◽

Genes Encoding

Previous studies have demonstrated the essential role of morphogenetic regulation in Fusarium oxysporum pathogenesis, including processes such as cell-wall biogenesis, cell division, and differentiation of infection-like structures. We identified three F. oxysporum genes encoding predicted transcription factors showing significant identities to Magnaporthe oryzae Con7p, Con7-1, plus two identical copies of Con7-2. Targeted deletion of con7-1 produced nonpathogenic mutants with altered morphogenesis, including defects in cell wall structure, polar growth, hyphal branching, and conidiation. By contrast, simultaneous inactivation of both con7-2 copies caused no detectable defects in the resulting mutants. Comparative microarray-based gene expression analysis indicated that Con7-1 modulates the expression of a large number of genes involved in different biological functions, including host–pathogen interactions, morphogenesis and development, signal perception and transduction, transcriptional regulation, and primary and secondary metabolism. Taken together, our results point to Con7-1 as general regulator of morphogenesis and virulence in F. oxysporum.

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