Mucilage production by wounded xylem tissue of maize roots — time course and stimulus

2003 ◽  
Vol 30 (7) ◽  
pp. 755 ◽  
Author(s):  
Laura J. Crews ◽  
Margaret E. McCully ◽  
Martin J. Canny
Keyword(s):  
Time Course ◽  
Living Cells ◽  
Root Cap ◽  
Experimental Investigations ◽  
Mechanical Wounding ◽  
Maize Roots ◽  
Acidic Polysaccharides ◽  
Xylem Tissue ◽  
Xylem Conduits ◽  
Xylem Function

As a reaction to invasion by pathogens, plants block their xylem conduits with mucilage, restricting pathogen advance. Wounding soil-grown roots of maize revealed that pectinaceous mucilage could be found in the vessels after 6 h, and abundantly filled most vessels up to 3 cm proximal to the wound after 1 d. Phenolics increased in the mucilage at later times. The same reactions occurred in vessels following mechanical wounding of axenically-grown roots, showing that the presence of microbes is not necessary for the response. The xylem mucilage is similar to root-cap mucilage in mode of extrusion from the periplasmic space of living cells through primary wall, apparent phase transition, and staining indicative of acidic polysaccharides. Whether other known properties of root-cap mucilage which might alter vessel functioning, such as reduction of surface tension and increased viscosity produced by dissolved solutes, are also common to xylem mucilage requires further investigation. However, our results indicate that possible influence of wounding-induced mucilage in xylem vessels should be considered in all experimental investigations of xylem function.

Short-and long-term effects of cadmium on transmembrane electric potential (E m) in maize roots

Biologia ◽  
2006 ◽  
Vol 61 (1) ◽  
Author(s):  
Ján Pavlovkin ◽  
Miroslava Luxová ◽  
Ingrid Mistríková ◽  
Igor Mistrík
Keyword(s):  
Root Growth ◽  
Electric Potential ◽  
Time Course ◽  
Cumulative Effect ◽  
Significant Inhibition ◽  
Long Term Effects ◽  
Cortical Cells ◽  
Root Cells ◽  
Maize Roots ◽  
Atp Supply

AbstractIn this study, the effects of Cd on root growth, respiration, and transmembrane electric potential (E m) of the outer cortical cells in maize roots treated with various Cd concentrations (from 1 µM to 1 mM) for several hours to one week were studied. The E m values of root cells ranged between −120 and −140 mV and after addition of Cd they were depolarized immediately. The depolarization was concentration-dependent reaching the value of diffusion potential (E D) when the Cd concentration exceeded 100 µM. The values of E D ranged between −65 to −68 mV (−66 ± 1.42 mV). The maximum depolarization of E m was registered approx. 2.5 h after addition of Cd to the perfusion solution and in some cases, partial (Cd > 100 µM) or complete repolarization (Cd < 100 µM) was observed within 8–10 h of Cd treatment. In the time-dependent experiments (0 to 168 h) shortly after the maximum repolarization of E m a continuous concentration-dependent decrease of E m followed at all Cd concentrations. Depolarization of E m was accompanied by both increased electrolyte leakage and inhibition of respiration, especially in the range of 50 µM to 1 mM Cd, with the exception of root cells treated with 1 and 10 µM Cd for 24 and 48 h. Time course analysis of Cd impact on root respiration revealed that at higher Cd concentrations (> 50 µM) the respiration gradually declined (∼ 6 h) and then remained at this lowest level for up to 24 h.All the Cd concentrations used in this experiment induced significant inhibition of root elongation and concentrations higher than 100 µM stopped the root growth within the first day of Cd treatment. Our results suggest that Cd does not cause irreversible changes in the electrogenic plasma membrane H+ ATPase because fusicoccin, an H+ ATPase activator diminished the depolarizing effect of Cd on the E m. The depolarization of E m in the outer cortical cells of maize roots was the result of a cumulative effect of Cd on ATP supply, plasmalemma permeability, and activity of H+ ATPase.

Airway epithelial tight junctions and binding and cytotoxicity ofPseudomonas aeruginosa

1999 ◽  
Vol 277 (1) ◽  
pp. L204-L217 ◽  
Author(s):  
Alfred Lee ◽  
Dar Chow ◽  
Brian Haus ◽  
Wanru Tseng ◽  
David Evans ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Tight Junctions ◽  
Propidium Iodide ◽  
Time Course ◽  
Living Cells ◽  
Airway Epithelial Cells ◽  
Airway Epithelial ◽  
Basolateral Membranes ◽  
Free Edges

The role of tight junctions in the binding and cytoxicity of Pseudomonas aeruginosato apical or basolateral membranes of lung airway epithelial cells was tested with fluorescence microscopy on living cells. Binding of noncytotoxic P. aeruginosa strain O1 was assessed with P. aeruginosa that expressed green fluorescent protein. Binding of cytotoxic P. aeruginosa strain 6206 was assessed with FITC-labeled P. aeruginosa; cytotoxicity was determined from nuclear uptake of the impermeant dye propidium iodide. The role of direct contact of P. aeruginosa to epithelial cells was tested with filters with small (0.45-μm) or large (2.0-μm) pores. High transepithelial resistance ( Rt) Calu-3 and cultured bovine tracheal monolayers ( Rt> 1,000 Ω ⋅ cm2) bound P. aeruginosa very infrequently (<1 P. aeruginosa/100 cells) at the apical membrane, but P. aeruginosabound frequently to cells near “free edges” at holes, wounds, islands, and perimeters; cytotoxicity required direct interaction with basolateral membranes. Wounded high Rtepithelia showed increased P. aeruginosa binding and cytotoxicity at the free edges because basolateral membranes were accessible to P. aeruginosa, and dead and living cells near the wound bound P. aeruginosa similarly. Compared with high Rtepithelia, low RtCFT1 ( Rt= 100–200 Ω ⋅ cm2) and EGTA-treated Calu-3 monolayers were 25 times more susceptible to P. aeruginosa binding throughout the monolayer. Cytotoxicity to CFT1 cells (throughout the confluent monolayer, not only at the free edge) occurred after a shorter delay (0.25 vs. 2.0 h) and then five times faster than to Calu-3 cells, indicating that the time course of P. aeruginosa cytotoxicity may be limited by the rate of gaining access through tight junctions and that this occurred faster in low Rtthan in high Rtairway epithelia. Cytotoxicity appeared to occur in a sequential process that led first to a loss of fura 2 and a later uptake of propidium iodide. P. aeruginosa bound three times more frequently to regions between cells (tight junctions?) than to cell membranes of low RtCFT1 cells.

scholarly journals Mechanical Wounding Induces Catalase Gene (VsCat) in Leaves of Common Vetch

2021 ◽  
Author(s):  
Saeid Abu-Romman ◽  
Tarek G. Ammari
Keyword(s):  
Time Course ◽  
Oxygen Species ◽  
Biotic Factors ◽  
Quantitative Real Time Pcr ◽  
Mechanical Wounding ◽  
Common Vetch ◽  
Catalase Gene ◽  
Defense Systems ◽  
Time Course Study ◽  
Scavenging Enzymes

Background: In plants, wounding can result from mechanical injuries or from biotic factors induced by herbivores infestation and pathogen infection. Wounding enhances the production of reactive oxygen species (ROS). Enzymatic and nonenzymatic defense systems have been reported in plants to immediately combat increased levels of ROS. Plant catalases are encoded by a multigene family and are the major scavenging enzymes catalyzing the dismutation of toxic hydrogen peroxide to water and dioxygen. Methods: In the preasent work, a quantitative real-time PCR was used to quantify the expression level of a catalase gene from common vetch (Vicia sativa; VsCat) in response to mechanical wounding. Result: The results of the time course study showed that the transcript levels of VsCat were significantly increased in wounded leaves at all-time points examined with a peak expression of 7.6 folds at 2 h post wounding. The increased expression of VsCat might represent a direct defense against elevated H2O2 generated during wounding.

scholarly journals Metal Nanoparticles in Laser Bioprinting

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2584
Author(s):  
Vyacheslav Zhigarkov ◽  
Ivan Volchkov ◽  
Vladimir Yusupov ◽  
Boris Chichkov
Keyword(s):  
Laser Pulse ◽  
Metal Nanoparticles ◽  
Pulse Heating ◽  
Living Cells ◽  
Good News ◽  
Experimental Investigations ◽  
Metal Absorption ◽  
Negative Effect ◽  
Laser Pulse Heating ◽  
Ti Films

Laser bioprinting is a promising method for applications in biotechnology, tissue engineering, and regenerative medicine. It is based on a microdroplet transfer from a donor slide induced by laser pulse heating of a thin metal absorption film covered with a layer of hydrogel containing living cells (bioink). Due to the presence of the metal absorption layer, some debris in the form of metal nanoparticles is printed together with bioink microdroplets. In this article, experimental investigations of the amount of metal nanoparticles formed during the laser bioprinting process and transported in bioink microdroplets are performed. As metal absorption layers, Ti films with the thickness in the range of 25–400 nm, produced by magnetron spattering, were applied. Dependences of the volume of bioink microdroplets and the amount of Ti nanoparticles within them on the laser pulse fluence were obtained. It has been experimentally found that practically all nanoparticles remain in the hydrogel layer on the donor slide during bioprinting, with only a small fraction of them transferred within the microdroplet (0.5% to 2.5%). These results are very important for applications of laser bioprinting since the transferred metal nanoparticles can potentially affect living systems. The good news is that the amount of such nanoparticles is very low to produce any negative effect on the printed cells.

Time course of anatomical changes to stem vascular tissues of alfalfa, Medicago sativa, from probing injury by the potato leafhopper, Empoasca fabae

1995 ◽  
Vol 73 (2) ◽  
pp. 288-298 ◽  
Author(s):  
Carol L. Ecale ◽  
Elaine A. Backus
Keyword(s):  
Time Course ◽  
Vascular Tissue ◽  
Wound Response ◽  
Tracheary Elements ◽  
Insect Feeding ◽  
Phloem Tissue ◽  
Cross Sectional ◽  
Standard Duration ◽  
Total Cross Sectional Area ◽  
Xylem Tissue

We used a videomicrography technique to apply standard-duration pulses of leafhopper probing damage to alfalfa stems, or manually punctured stems with an implement resembling leafhopper stylets, to compare damage induction and chronicle the plant's anatomical responses over time. Plants were examined at 0.5, 1, 2, 4, and 8 days after probing. Leafhopper probing occurred primarily in phloem tissue: stylets damaged and deposited sheath saliva primarily in phloem. Between days 1 and 4, collapsed phloem cells and sheath saliva deposits were dissolved and removed as surviving cells adjacent to stylet pathways underwent enlargement and division. By day 8, phloem tissue assumed a near-normal appearance when viewed in cross section, although it is not known whether phloem functionality was restored. In contrast, xylem tissue suffered reduction in size, quantity, and total cross-sectional area of mature tracheary elements. These effects to vascular tissue may be responsible for all subsequent symptoms of hopperburn in alfalfa. Damage to phloem and xylem in mechanically punctured stems was slight and was similar for all time points. Key words: plant wound response, plant vascular development, phloem, xylem, hopperburn, insect feeding behaviour.

Specific attraction to and infection of cotton root cap cells by zoospores of Pythium dissotocum

1989 ◽  
Vol 67 (6) ◽  
pp. 1760-1767 ◽  
Author(s):  
N. P. Goldberg ◽  
M. C. HAwes ◽  
M. E. Stanghellini
Keyword(s):  
Living Cells ◽  
Gossypium Barbadense ◽  
Root Cap ◽  
Chemotactic Response ◽  
Agrostis Palustris ◽  
Isolated Cells ◽  
Cotton Species ◽  
Pythium Dissotocum ◽  
Zoospore Suspension ◽  
Individual Root

Root cap cells of two cotton species (Gossypium barbadense L. and G. hirsutum L.) elicited a specific chemotactic response in zoospores of Pythium dissotocum. When roots of cotton seedlings were placed into a suspension of Pythium dissotocum zoospores, there was immediate attraction, accumulation, and encystment exclusively in the root cap region. Seedlings which attracted zoospores were killed within 24 h. Furthermore, root cap cells remained attractive when isolated nondestructively from the root and placed into a zoospore suspension; attraction, accumulation, and encystment on individual root cap cells occurred within seconds after contact. Penetration and death of isolated cells occurred within 15–30 min. After 30 min, approximately 25% of living cells were directly colonized by zoospores. Root cap cells killed by freezing or drying remained attractive but at a reduced level; approximately half as many killed cells as living cells were directly colonized by zoospores. The number of root cap cells directly colonized by zoospores did not increase with time. In contrast, zoospores of Pythium catenulatum that exhibited a chemotactic response to Agrostis palustris (Bentgrass) were not attracted to and did not infect cotton seedlings or isolated root cap cells.

scholarly journals The Root Cap Determines Ethylene-Dependent Growth and Development in Maize Roots

2008 ◽  
Vol 1 (2) ◽  
pp. 359-367 ◽  
Author(s):  
Achim Hahn ◽  
Roman Zimmermann ◽  
Dierk Wanke ◽  
Klaus Harter ◽  
Hans G. Edelmann
Keyword(s):  
Growth And Development ◽  
Root Cap ◽  
Maize Roots ◽  
Dependent Growth

Do detached root-cap cells influence bacteria associated with maize roots?

1990 ◽  
Vol 13 (8) ◽  
pp. 793-801 ◽  
Author(s):  
M. B. GOCHNAUER ◽  
L. J. SEALEY ◽  
M. E. McCULLY
Keyword(s):  
Root Cap ◽  
Maize Roots

scholarly journals The first assessment of the stress inducible defense of Leucaena leucocephala with acaricidal potential effect against Rhipicephalus (Boophilus) microplus (Acari: Ixodidae)

2017 ◽  
Vol 26 (2) ◽  
pp. 171-176 ◽  
Author(s):  
Lêdia Feitosa Wanderley ◽  
Karla Lílian Rodrigues Batista ◽  
Jorgiane Furtado de Carvalho ◽  
Aldilene da Silva Lima ◽  
Gabriel Alves Landulfo ◽  
...  
Keyword(s):  
Protein Content ◽  
Leucaena Leucocephala ◽  
Egg Production ◽  
Time Course ◽  
Acaricidal Activity ◽  
Boophilus Microplus ◽  
Protein Extract ◽  
Mechanical Wounding ◽  
Defense Proteins ◽  
The Impact

Abstract Plants respond to wounding caused by mechanical stress or herbivory by synthesizing defense proteins. There are no studies reporting the action of induced plant proteins against ticks. The aim of this study was to investigate the effect of mechanically wounded Leucaena leucocephala leaves against Rhipicephalus (Boophilus) microplus. Initially, we carried out time course experiments to evaluate the impact of mechanical wounding on the protein content and the peroxidase, catalase and protease inhibitor activities in L. leucocephala. We then evaluated the acaricidal activity on R. (B.) microplus from protein extract collected from L. leucocephala after mechanical wounding. L. leucocephala leaves were artificially wounded, and after 6, 12, 24 and 48h, the leaves were collected for protein extraction. Quantitative and qualitative analyses of the proteins were performed. The protein content and peroxidase and protease activities increased 12h after wounding, and the acaricidal activity of this protein extract was evaluated using engorged R. (B.) microplus females. The protein extract obtained after wounding reduced egg production (8.5%) compared to those without wounding. Furthermore, the extract reduced egg hatching by 47.7% and showed an overall efficacy of 56.3% at 0.1 mgP/mL of the protein. We demonstrated that L. leucocephala defensive proteins could be effective against R. (B.) microplus.

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