The pen and the sword: recovering the disciplinary identity of physiology and anatomy before 1800: I: Old physiology—the pen

It is argued that the disciplinary identity of anatomy and physiology before 1800 are unknown to us due to the subsequent creation, success and historiographical dominance of a different discipline—experimental physiology. The first of these two papers deals with the identity of physiology from its revival in the 1530s, and demonstrates that it was a theoretical, not an experimental, discipline, achieved with the mind and the pen, not the hand and the knife. The physiological work of Jean Fernel, Albrecht von Haller and others is explored to prove this point. In conclusion this old physiological tradition is compared to the new experimental physiology, as practised by François Magendie and Pierre Flourens.     

Nitrogen fixation by photosynthetic bacteria

In 1949, Howard Gest and Martin Kamen published two brief papers in Science that changed our perceptions about the metabolic capabilities of photosynthetic bacteria. Their discovery of photoproduction of hydrogen and the ability of Rhodospirillum rubrum to fix nitrogen led to a greater understanding of both processes. This revised version was published online in June 2006 with corrections to the Cover Date.     

The history of photosynthetic thermoluminescence

A fundamental discovery of photosynthetis research in the 1950s was the detection of thermally stimulated light emission from preilluminated photosynthetic material [Arnold W and Sherwood H (1957) Proc Natl Acad Sci USA 43: 105–114]. This phenomenon, called thermoluminescence (TL), is characteristic of a wide range of materials (minerals, semiconductors, inorganic and organic crystals, and complex biological systems), which share the ability of storing radiant energy in thermally stabilized trap states. The original discovery of TL in dried chloroplasts later proved to be a phenomenon common to all photosynthetic organisms: photosynthetic bacteria, cyanobacteria, algae and higher plants, which can be observed in isolated membrane particles, intact chloroplasts and unicellular organisms, and whole leaves. Following the initial observations considerable effort has been devoted to the identification and characterization of photosynthetic TL components. This work has firmly established the participation of various oxidation states of the water-oxidizing complex, the redox-active tyrosines, and the quinone electron acceptors of Photosystem II (PS II) in the generation of photosynthetic glow curves. Since TL characteristics are very sensitive to subtle changes in the redox properties of the involved electron transport components, the TL method has become a powerful tool in probing a wide range of PS II redox reactions and their modifications by environmental stress effects. Here, the main milestones of research in photosynthetic TL are covered until the present day. This revised version was published online in August 2006 with corrections to the Cover Date.     

Electron donors and acceptors in the initial steps of photosynthesis in purple bacteria: a personal account

The discovery by Louis N. M. Duysens in the 1950s that illumination of photosynthetic purple bacteria can cause oxidation of either a bacteriochlorophyll complex (P) or a cytochrome was followed by an extended period of uncertainty as to which of these processes was the `primary' photochemical reaction. Similar questions arose later about the roles of bacteriopheophytin (BPh) and quinones as the initial electron acceptor. This is a personal account of kinetic measurements that showed that electron transfer from P to BPh occurs in the initial step, and that the oxidized bacteriochlorophyll complex (P⁺) then oxidizes the cytochrome while the reduced BPh transfers an electron to a quinone. This revised version was published online in August 2006 with corrections to the Cover Date.     

Linking the xanthophyll cycle with thermal energy dissipation*

This perspective summarizes my personal recollections about the initial discovery of the involvement of the xanthophyll cycle in photoprotective energy dissipation, starting with my arrival at Olle Björkman's laboratory at the Carnegie Institution and focusing on events from the mid-1980s to the early 1990s.     

On some aspects of photosynthesis revealed by photoacoustic studies: a critical evaluation

Photoacoustic techniques have been widely developed in photosynthesis research since the 1970s. We can divide the progress in this field into three periods. In the first period, a pioneer, William W. Parson (and his co-workers) discovered that the photochemical charge separation is accompanied by a conformation change. In the second period, the technique was essentially used to measure the two components of photochemical activity detected in the gas phase: energy storage (photothermal effect) and gas exchange (photobaric effect). In the third period, the time resolution and sensitivity of detection in liquid phase were significantly improved. In reviewing this last period, we shall focus on three aspects: conformation changes, thermodynamic parameters, and quantum yield spectra. This revised version was published online in August 2006 with corrections to the Cover Date.     

The problematic unity of biometrics

The word "biometry" may be less than 200 years old, but it can be argued that work we would now consider biometric dates back even to the pre-Christian era. The unity of biometry is attested through examples spanning two millennia, and a lesson from Francis Galton is recalled from a century ago.     

Quantitative Assessment of Current Risks to Harlequin Ducks in Prince William Sound,Alaska, from the Exxon Valdez Oil Spill

Harlequin Ducks (Histrionicus histrionicus) were adversely affected by the Exxon Valdez oil spill (EVOS) in Prince William Sound (PWS), Alaska, and some have suggested effects continue two decades later. We present an ecological risk assessment evaluating quantitatively whether PWS seaducks continue to be at-risk from polycyclic aromatic hydrocarbons (PAHs) in residual Exxon Valdez oil. Potential pathways for PAH exposures are identified for initially oiled and never-oiled reference sites. Some potential pathways are implausible (e.g., a seaduck excavating subsurface oil residues), whereas other pathways warrant quantification. We used data on PAH concentrations in PWS prey species, sediments, and seawater collected during 2001–2008 to develop a stochastic individual-based model projecting assimilated doses to seaducks. We simulated exposures to 500,000 individuals in each of eight age/gender classes, capturing the variability within a population of seaducks living in PWS. Doses to the maximum-exposed individuals are ～400–4,000 times lower than chronic toxicity reference values established using USEPA protocols for sea- ducks. These exposures are so low that no individual-level effects are plausible, even within a simulated population that is orders-of-magnitude larger than exists in PWS. We conclude that toxicological risks to PWS seaducks from residual Exxon Valdez oil two decades later are essentially non-existent.     

The priority dispute over the function of the lymphatic system and Glisson's ghost (the 18th-century Hunter-Monro Feud)

Basic Immunology has had only two significant public priority disputes. The first began in the late 1650s and concerned the recognition of the peripheral network of vessels which collects lymph throughout the body. The publication of this major anatomical discovery prompted a priority feud discussed in a previous paper. The subject of this essay is the second dispute which occurred a century later in the late 1750s. It focused on the function of the lymphatic system and precipitated a heated war of words between a young Scotch medical graduate (Alexander Monro) and a noted London anatomist (William Hunter). Their published charges and responses ranged from feigned respect to ad hominen invectives. But in retrospect, the priority claims of both were precluded by the observations and speculations of an Englishman (Francis Glisson) a full century before. The several editions of his work were unknown to Hunter and Monro at the inception of their feud.