Robert C. Palmer

Calcium-mediated apoptosis in a plant hypersensitive disease resistance response

BACKGROUND Avirulent pathogens elicit a battery of plant defenses, often accompanied by collapse of the challenged cells. In soybean cells, sustained accumulation of H2O2 from an oxidative burst cues localized host cell death. Such hypersensitive cell death appears to be an active process, but little is known about the mechanisms underlying cellular collapse. RESULTS We show that H2O2 stimulates a rapid influx of Ca2+ into soybean cells, which activates a physiological cell death program resulting in the generation of large (approximately 50 kb) DNA fragments and cell corpse morphology--including cell shrinkage, plasma membrane blebbing and nuclear condensation--characteristic of apoptosis. In contrast, H2O2 induction of the cellular protectant gene glutathione S-transferase is Ca(2+)-independent. Apoptosis in soybean cells and leaf tissue was induced by avirulent Pseudomonas syringae pv. glycinea but was not observed at comparable stages of the compatible interaction with the isogenic virulent strain, which fails to elicit a hypersensitive response. Apoptosis was also observed at the onset of the hypersensitive response in Arabidopsis leaves inoculated with avirulent P. syringae pv. tomato and in tobacco cells treated with the fungal peptide cryptogein, which is involved in the induction of non-host resistance to Phytophthora cryptogea. CONCLUSIONS These observations establish a signal function for Ca2+ downstream of the oxidative burst in the activation of a physiological cell death program in soybean cells that is similar to apoptosis in animals. That the characteristic cell corpse morphology is also induced in Arabidopsis and tobacco by different avirulence signals suggests that apoptosis may prove to be a common, but not necessarily ubiquitous, feature of incompatible plant-pathogen interactions. Emerging similarities between facets of hypersensitive disease resistance and the mammalian native immune system indicate that apoptosis is a widespread defence mechanism in eukaryotes.

The Origins of Property in England

The English common law of real property, as S.F.C. Milsom has argued, took shape between 1153 and 1215. The common law gave royal protection to free tenements, replacing feudal relationships as the primary bond structuring society. The law thus constituted the institutional core of the English state. But no Machiavellian monarch constructed the English state. Henry II was, rather, a king who presumed the morality and necessity of feudal relationships. His innovations, though intentional and carefully planned, were directed at narrower and less far-sighted ends. Other changes were the result of bureaucratic action. The complex interplay between present-oriented political or juridical decisions and bureaucratic rigor generated a legal system.

The Whilton Dispute, 1264-1380: A Social-Legal Study of Dispute Settlement in Medieval England

Robert C. Palmer examines the Whilton dispute, an intrafamilial, multigenerational contest over a large estate that continued, primarily in the courts, from 1264until 1380.Originally published in 1984.The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These paperback editions preserve the original texts of these important books while presenting them in durable paperback editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.

The Federal Common Law of Crime

The United States Constitution established a federal system, not a national government. States continued necessarily and by design as active and important centers of governmental activity. States were institutions of inherent authority, while the federal government by original intent and then explicitly by amendment, was a government of only delegated powers. Since the federal government derived its power directly from the people and acted directly on individuals, it was decisively more powerful than the pre-Constitution Confederation. But the Bill of Rights itself is evidence of the continued worry, pervasive until modified by the Reconstruction Amendments, that the federal government might, but should not, overwhelm the states.