Proceedings of the Biological Society of Washington.

v. 7 (1892)

Proceedings of the Biological Society of Washington.

v. 14 (1901)

Proceedings of the Biological Society of Washington.

v. 16 (1903)

Proceedings of the Biological Society of Washington.

v. 6 (1890-1891)

Proceedings of the Biological Society of Washington.

v. 5 (1888-1890)

Proceedings of the Biological Society of Washington.

v. 13 (1899-1900)

Proceedings of the Biological Society of Washington.

v. 15 (1902)

Proceedings of the Biological Society of Washington.

v. 4 (1886-1888)

Proceedings of the Biological Society of Washington.

v. 12 (1898)

Comparison of Binding Properties and Early Biological Effects of Elicitins in Tobacco Cells1

Elicitins are a family of small proteins secreted by Phytophthora species that have a high degree of homology and elicit defense reactions in tobacco (Nicotiana tabacum). They display acidic or basic characteristics, the acidic elicitins being less efficient in inducing plant necrosis. In this study we compared the binding properties of four elicitins (two basic and two acidic) and early-induced signal transduction events (Ca2+ influx, extracellular medium alkalinization, and active oxygen species production). The affinity for tobacco plasma membrane-binding sites and the number of binding sites were similar for all four elicitins. Furthermore, elicitins compete with one another for binding sites, suggesting that they interact with the same receptor. The four elicitins induced Ca2+ influx, extracellular medium alkalinization, and the production of active oxygen species in tobacco cell suspensions, but the intensity and kinetics of these effects were different from one elicitin to another. As a general observation the concentrations that induce similar levels of biological activities were lower for basic elicitins (with the exception of cinnamomin-induced Ca2+ uptake). The qualitative similarity of early events induced by elicitins indicates a common transduction scheme, whereas fine signal transduction tuning is different in each elicitin.

Biological Activity of Reducing-End-Derivatized Oligogalacturonides in Tobacco Tissue Cultures1

The biological activity of reducing-end-modified oligogalacturonides was quantified in four tobacco (Nicotiana tabacum) tissue culture bioassays. The derivatives used were oligogalacturonides with the C-1 of their reducing end (a) covalently linked to a biotin hydrazide, (b) covalently linked to tyramine, (c) chemically reduced to a primary alcohol, or (d) enzymatically oxidized to a carboxylic acid. These derivatives were tested for their ability to (a) alter morphogenesis of N. tabacum cv Samsun thin cell-layer explants, (b) elicit extracellular alkalinization by suspension-cultured cv Samsun cells, (c) elicit extracellular alkalinization by suspension-cultured N. tabacum cv Xanthi cells, and (d) elicit H2O2 accumulation in the cv Xanthi cells. In all four bioassays, each of the derivatives had reduced biological activity compared with the corresponding underivatized oligogalacturonides, demonstrating that the reducing end is a key element for the recognition of oligogalacturonides in these systems. However, the degree of reduction in biological activity depends on the tissue culture system used and on the nature of the specific reducing-end modification. These results suggest that oligogalacturonides are perceived differently in each tissue culture system.

Proceedings of the Biological Society of Washington.

v. 11 (1897)

Act of incorporation, constitution and by-laws of the National society of the Daughters of the American revolution.

Mode of access: Internet.

Index of the Rolls of honor (ancestor's index) in the Lineage books of the National society of the Daughters of the American revolution, volumes 41 to 80.

Mode of access: Internet.