The interaction of divalent cations with pectic substances and their influence on acid-induced cell wall loosening

1981 ◽  
Vol 59 (8) ◽  
pp. 1522-1525 ◽  
Author(s):  
Mark Tepfer ◽  
Iain E. P. Taylor
Keyword(s):  
Cell Wall ◽  
Growth Inhibition ◽  
Binding Affinity ◽  
Higher Plants ◽  
Divalent Cations ◽  
Cation Binding ◽  
Cell Wall Loosening ◽  
Good Correspondence ◽  
Cation Binding Site ◽  
Wall Loosening

Certain divalent cations are potent inhibitors of acid-induced cell wall loosening in both higher plants and green algae. It has been proposed that this inhibition involves the formation of pectic gels in the cell wall. To test this hypothesis, we have looked for a relationship between the ability of various ions to inhibit growth and (i) their ability to cause gelation of isolated pectins, (ii) their binding affinity for isolated cell walls, and (iii) their binding affinity for purified pectin. There is good correspondence between the effectiveness of an ion as a growth inhibitor and its binding affinity for the cell wall. There is very poor correspondence between growth inhibition and the ability to induce the gelation of pectin. Our results indicate that pectic gel formation is not involved in cation-induced growth inhibition, but that the major cation binding site in the cell wall may be involved in a nongel-forming capacity.

scholarly journals Genome-Wide Identification of the Expansin Gene Family and Its Potential Association with Drought Stress in Moso Bamboo

2020 ◽  
Vol 21 (24) ◽  
pp. 9491
Author(s):  
Kang-Ming Jin ◽  
Ren-Ying Zhuo ◽  
Dong Xu ◽  
Yu-Jun Wang ◽  
Hui-Jin Fan ◽  
...  
Keyword(s):  
Cell Wall ◽  
Abscisic Acid ◽  
Abiotic Stress ◽  
Gene Family ◽  
Moso Bamboo ◽  
Structure Evolution ◽  
Dependent Manner ◽  
Cell Wall Loosening ◽  
Expansin Gene ◽  
Wall Loosening

Expansins, a group of cell wall-loosening proteins, are involved in cell-wall loosening and cell enlargement in a pH-dependent manner. According to previous study, they were involved in plant growth and abiotic stress responses. However, information on the biological function of the expansin gene in moso bamboo is still limited. In this study, we identified a total of 82 expansin genes in moso bamboo, clustered into four subfamilies (α-expansin (EXPA), β-expansin (EXPB), expansin-like A (EXLA) and expansin-like B (EXPB)). Subsequently, the molecular structure, chromosomal location and phylogenetic relationship of the expansin genes of Phyllostachys edulis (PeEXs) were further characterized. A total of 14 pairs of tandem duplication genes and 31 pairs of segmented duplication genes were also identified, which may promote the expansion of the expansin gene family. Promoter analysis found many cis-acting elements related to growth and development and stress response, especially abscisic acid response element (ABRE). Expression pattern revealed that most PeEXs have tissue expression specificity. Meanwhile, the expression of some selected PeEXs was significantly upregulated mostly under abscisic acid (ABA) and polyethylene glycol (PEG) treatment, which implied that these genes actively respond to expression under abiotic stress. This study provided new insights into the structure, evolution and function prediction of the expansin gene family in moso bamboo.

Ion behaviour in plant cell walls. IV. Selective cation binding by Sphagnum russowii cell walls

1990 ◽  
Vol 68 (4) ◽  
pp. 773-781 ◽  
Author(s):  
Conrad Richter ◽  
Jack Dainty
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Divalent Cations ◽  
Selectivity Coefficient ◽  
Weak Acid ◽  
Small Population ◽  
Cation Binding ◽  
Trivalent Cations ◽  
Using Data ◽  
A Site

Selective cation binding by Sphagnum russowii cell walls was investigated using data from bicationic potentiometric titrations of isolated cell walls. Selectivity measurements were interpreted in the context of Manning condensation. In titrations with cations of different valency, selectivity favoured the higher valency cation, as expected in Manning condensation. This selectivity generally increased with bathing pH until the wall-bound polyuronic acids became fully ionized (pH > 5). The selectivity coefficient order at full ionization was Na+–Ca2+ > Na+–La3+ > Ca2+–La3+, as predicted by the weak acid Donnan–Manning (WADM) model. Other phenomena also appear to influence binding selectivity. A small population of isolated binding sites are more effectively neutralized by univalent (or divalent) than divalent (or trivalent) cations. High selectivity for cations of lower valency at low pH also suggests a site isolation effect. In bicationic titrations involving divalent cations only, Sr24+ and Ca2+ were bound by the cell wall with approximately equal effectiveness, as predicted by the WADM model. However, cation or binding site specificities probably account for the favoured binding of Ca2+ over Mg2+ by the cell wall. Key words: ion exchange, cell wall, selectivity.

scholarly journals Chemical properties of the divalent cation binding site on potassium channels.

1992 ◽  
Vol 100 (2) ◽  
pp. 181-193 ◽  
Author(s):  
S Spires ◽  
T Begenisich
Keyword(s):  
Potassium Channels ◽  
Binding Site ◽  
Divalent Cation ◽  
Divalent Cations ◽  
Chemical Properties ◽  
Cation Binding ◽  
Solution Ph ◽  
Electrophysiological Properties ◽  
Cation Binding Site ◽  
Voltage Gated Ion Channels

The actions of divalent cations on voltage-gated ion channels suggest that these cations bind to specific sites and directly influence gating kinetics. We have examined some chemical properties of the external divalent cation binding sites on neuronal potassium channels. Patch clamp techniques were used to measure the electrophysiological properties of these channels and Zn ions were used to probe the divalent cation binding site. The channel activation kinetics were greatly (three- to fourfold) slowed by low (2-5 mM) concentrations of Zn; deactivation kinetics were only slightly affected. These effects of Zn were inhibited by low solution pH in a manner consistent with competition between Zn and H ions for a single site. The apparent inhibitory pK for this site was near 7.2. Treatment of the neurons with specific amino acid reagents implicated amino, but no histidyl or sulfhydryl, residues in divalent cation binding.

scholarly journals Temporal expression patterns of fruit-specific α- EXPANSINS during cell expansion in bell pepper (Capsicum annuum L.)

2020 ◽  
Author(s):  
Andrés Mayorga-Gómez ◽  
Savithri Nambeesan
Keyword(s):  
Cell Wall ◽  
Cell Expansion ◽  
Growth And Development ◽  
Expression Patterns ◽  
Fruit Growth ◽  
Bell Pepper ◽  
Temporal Expression ◽  
Cell Wall Loosening ◽  
Pepper Fruit ◽  
Wall Loosening

Abstract Background Expansins (EXP) facilitate non-enzymatic cell wall loosening during several phases of plant growth and development including fruit growth, internode expansion, pollen tube growth, leaf and root development, and during abiotic stress responses. In this study, the spatial and temporal expression patterns of C. annuum α- EXPANSINS (CaEXPA) genes were characterized. Additionally, fruit-specific CaEXPA expression was correlated with the rate of cell expansion during bell pepper fruit development. Results Spatial expression patterns revealed that CaEXPA13 was up-regulated in vegetative tissues and flowers, with the most abundant expression in mature leaves. Expression of CaEXPA4 was associated with stems and roots. CaEXPA3 was expressed abundantly in flower at anthesis suggesting a role for CaEXPA3 in flower development. Temporal expression analysis revealed that 9 out of the 21 genes were highly expressed during fruit development. Of these, expression of six genes, CaEXPA5, CaEXPA7, CaEXPA12, CaEXPA14 CaEXPA17 and CaEXPA19 were abundant 7 to 21 days after anthesis (DAA), whereas CaEXP6 was strongly expressed between 14 and 28 DAA. Further, this study revealed that fruit growth and cell expansion occur throughout bell pepper development until ripening, with highest rates of fruit growth and cell expansion occurring between 7 and 14 DAA. The expression of CaEXPA14 and CaEXPA19 positively correlated with the rate of cell expansion, suggesting their role in post-mitotic cell expansion-mediated growth of the bell pepper fruit. In this study, a ripening specific EXP transcript, CaEXPA9 was identified, suggesting its role in cell wall disassembly during ripening.Conclusion This is the first genome-wide study of CaEXPA expression during fruit growth and development. Identification of a fruit-specific EXPAs suggest their importance in facilitating cell expansion during growth and cell wall loosening during ripening in bell pepper. These EXPA genes could be important targets for future manipulation of fruit size and ripening characteristics.

scholarly journals Temporal expression patterns of fruit-specific α- EXPANSINS during cell expansion in bell pepper (Capsicum annuum L.)

2020 ◽  
Author(s):  
Savithri Nambeesan ◽  
Andrés Mayorga-Gómez
Keyword(s):  
Cell Wall ◽  
Cell Expansion ◽  
Growth And Development ◽  
Expression Patterns ◽  
Fruit Growth ◽  
Bell Pepper ◽  
Temporal Expression ◽  
Cell Wall Loosening ◽  
Pepper Fruit ◽  
Wall Loosening

Abstract BackgroundExpansins (EXP) facilitate non-enzymatic cell wall loosening during several phases of plant growth and development including fruit growth, internode expansion, pollen tube growth, leaf and root development, and during abiotic stress responses. In this study, we characterized the spatial and temporal expression pattern of C. annuum α- EXPANSINS (CaEXPA) genes. Additionally, we correlated fruit-specific CaEXPA expression with the rate of cell expansion during bell pepper fruit development. ResultsSpatial expression patterns revealed that CaEXPA13 was up-regulated in vegetative tissues and flowers, with the most abundant expression in mature leaves. Expression of CaEXPA4 was associated with stems and roots. CaEXPA3 was expressed abundantly in flower at anthesis suggesting a role for CaEXPA3 in flower development. Temporal expression analysis revealed that 9 out of the 21 genes were highly expressed during fruit development. Of these, expression of six genes, CaEXPA5, CaEXPA7, CaEXPA12, CaEXPA14 CaEXPA17 and CaEXPA19 were abundant 7 to 21 days after anthesis (DAA), whereas CaEXP6 was strongly expressed between 14 and 28 DAA. Further, this study revealed that fruit growth and cell expansion occur throughout bell pepper development until ripening, with highest rates of fruit growth and cell expansion occurring between 7 and 14 DAA. The expression of CaEXPA14 and CaEXPA19 positively correlated with the rate of cell expansion, suggesting their role in post-mitotic cell expansion-mediated growth of the bell pepper fruit. In this study, we also identified high transcript abundance of CaEXPA9 during ripening.ConclusionThis is the first genome-wide study of CaEXPA expression during fruit growth and development. We identified a fruit-specific EXPA that may be important in facilitating cell expansion during growth and cell wall loosening during ripening in bell pepper. These EXPA genes could be important targets for future manipulation of fruit size and ripening characteristics.

scholarly journals Xyloglucan Antibodies Inhibit Auxin-Induced Elongation and Cell Wall Loosening of Azuki Bean Epicotyls but Not of Oat Coleoptiles

1991 ◽  
Vol 96 (2) ◽  
pp. 551-557 ◽  
Author(s):  
Takayuki Hoson ◽  
Yoshio Masuda ◽  
Yoshiaki Sone ◽  
Akira Misaki
Keyword(s):  
Cell Wall ◽  
Azuki Bean ◽  
Cell Wall Loosening ◽  
Wall Loosening
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