Thomas P. Coohill

Department of Physics
Siena College, Loudonville, NY 12211-1462

An Apology and an Explanation
This chapter derives from a presentation at the 13th International Congress on Photobiology meeting of the Association Internationale de Photobiologie [AIP, now IUPB (see table 18)] in San Francisco, USA, July 2000, updated in April 2008. It, therefore, will be broad and topical rather than detailed. I will highlight the progress of certain fields through example rather than attempt a comprehensive review of any of them. To review the results of such a wide area of research would require several volumes. The few pages presented here can only be a severely limited synopsis of major achievements. The work of a few researchers will be emphasized. It is certain that some areas will be neglected due to the limited knowledge of the author. It will be clear that Photobiology will be highlighted whereas Photochemistry will be interspersed under the separate headings, e.g., citing the role of singlet oxygen in the table for photodynamic treatment. The past will be emphasized over the present since it easier to sort out. It is with a great deal of trepidation that I attempt even this limited summary. Major areas of research and major contributors to each field will be left unmentioned. Apologies are no substitute for ignorance but may assuage the ire of some. I hope that I have cited people's work correctly.


Table 1 lists some advantages of using light to study biological processes (Jagger, 1967). Photobiological techniques are sometimes less invasive than those used in other areas of science, allowing the sample to respond without incurring much damage. It is no coincidence that two of the most important macromolecules in biology - DNA and chlorophyll - respond readily to light. In fact absorption of light by plants is the driving force for much of the life on earth. Accordingly, studies involving these two molecules and human responses dominated early work in Photobiology. As we will see below, additional research areas also utilized light effects, thus broadening Photobiology into a truly cross-disciplinary science. Thus, photobiologists are found in many occupations; from agriculture to physics and chemistry; from oceanography to medicine. So it is expected that they have made significant progress this past century.

Table 1. Some advantages to using light to study biological processes
  • many bio-molecules (e.g., DNA, chlorophyll) absorb and are affected by light
  • the target chromophores are sometimes well known
  • the photochemistry of many bio-processes is well understood
  • some photoprocesses can be elicited without causing permanent cellular damage
  • light treatment is not necessarily toxic
  • light treatment is harmless to molecules that do not absorb at the source wavelengths (the photon has to be absorbed to cause an effect)
  • therefore, light penetration into cells and tissues need not be invasive
  • light sources are often inexpensive and easy to operate and quantify.


Finsen - 1900 - Light as Therapy
Photobiology progressed along several fronts starting in 1900. Human responses to solar radiation dominated the early concerns, not, as is currently in vogue, due to its harmful effects, but rather, due to its therapeutic use. So, it is easy to choose the first photobiologist to mention in any review of the century - Niels Ryberg Finsen. Finsen saw the value of exposing patients to the sun to treat a variety of diseases, such as lupus lupus vulgaris (skin tuberculosis - Finsen, 1900). He first made a large glass lens to focus the sun's rays and employed a copper sulfate solution as a filter (which eliminated the UV-B). It worked to some extent. He then decided it would be easier to set up an indoor clinic and expose patients to the output of a powerful carbon arc lamp - thereby adding back the UV-B. This intense light treatment was successful in many cases and started the new field of phototherapy. For this work, Finsen was awarded the third Nobel Prize in physiology and medicine in 1903. The citation stated:

in recognition of his contribution to the treatment of diseases,
especially lupus vulgaris, with concentrated light radiation,
whereby he has opened a new avenue for medical science.

Table 2. Finsen Medalists 1937-2004
1937CornoSwitzerland     1976BlumUSA
1951Rollier Switzerland    Hendricks USA
  Jausion France  ShugarPoland
1954CoblentzUSA 1980Setlow USA
1959RottierNetherlands 1984SmithUSA
 TereninUSSR  Haupt Germany
 RupertUSA 1988MagnusUK
1968HollaenderUSA  ArnonUSA
 BowenUK 1992UrbachUSA
 StilesUK  StoeckeniusUSA
1972Forster Germany  1996 Van der Leun Netherlands
 HillUK  KondoJapan
 LatarjetFrance 2000 YoshizawaJapan
     Briggs USA
 LatarjetFrance 2004 EpsteinUSA
     Furuya Japan

We honor him by awarding a prominent researcher the Finsen Medal every four years and by the establishment of the Finsen Lecture series at IUPB international meetings.

Table 3. Finsen Lectures 1980-2004
1980   Junge   Germany
1984 Vogelmann Sweden
1988 Ley USA
1992 Satoh Japan
1996 Brash USA
  Schwarz Germany
2000  Petrich USA
2004  Yarosh USA

Thus began the era of heliotherapy and the solarium, the building of mountain retreats for the phototherapy of guests and the widespread belief that exposure to sunlight was healthy and invigorating.

For convenience, intensity and spectral purity, better light sources were developed as the century progressed.

Table 4. Phototherapy
1870    description of XP Kaposi
1900 to World War II - The Glory Days of Phototherapy
1900 TB treatment  Finsen (Nobel Prize)
1911 transmission into skin Hassalbach, Chance, Yodh, Patterson, Gratton
1919 rickets treatment Huldschinsky
1925 UV causes vitamin D production Steenbock, Daniels
After World War II, Pills Replace Photons until UVA treatment emerged
1970 psoriasis Fitzpatrick, Parrish, Pathak, Wolf, Hönigsmann
1980 photodynamic therapy, photomedicine
 Dougherty, Kessel, Hearst, Dall'Acqua,
Rodighiero, Averbeck, Gasparro
1997 Excimer laser (psoriasis, vitiligo)
 Bónis, Kemény, Dobozy
Anderson, Taylor

Table 5. Tools
5x109 B.C. sunGod, Bernhardt, Rollier, Dorno, Saidman
1850-1990 artificial sources; carbon, Hg, xenon Finsen, Kromayer
1666; 1859 spectroscope Newton; Kirckhoff, Bunsen
1880 monochromator
Wadsworth, Magnus, Latarjet,
Saidman, Johns
1960 laser
Sorokin, Wynne, Berns, Ashkin,
Anderson, Taroni
1980 synchrotron radiation Ito, Sutherland, Munro
lenses, prisms, filters…plus numerous chemical and biological devices and assay methods

Hausser, Human Skin and the Beginnings of Action Spectroscopy
It was because he was diagnosed with tuberculosis that the German physicist Hausser went to a heliotherapy retreat in the Alps. Hausser (Hausser and Vahle, 1927, 1969) noted that "a long hike on a glacier, in the afternoon hours under a burning sun had almost no effect, while … a brief sojourn on snow at noontime resulted in a severe sunburn." This observation led him to construct the first true action spectrum (of the kind now widely used) for erythema. The importance of this work cannot be over emphasized. It was the first detailed examination of a biological effect as a function of wavelength, and pointed to the beginnings of a means for determining the molecule(s) responsible for that effect. Hausser realized the difficulties that humans posed as laboratory subjects and switched to bananas. His photo of the mercury spectrum singed into the skin of a banana (Hausser and Oehmcke, 1933) remains one of the most convincing simple displays of biological response to individual wavelengths. Hausser's work was careful enough and employed proper controls to also allow him to discover the phenomenon of photoreactivation of short wavelength UV damage by subsequent exposure to radiation of longer wavelength (Hausser and Vahle, 1931). After Hausser there was steady progress in examining the effects of light (mainly UV) on human skin, much of it centered on unraveling the role of light in photocarcinogenesis. Blum (1959) and others (Urbach, 1993 and 1997; Urbach, et al., 1976) spearheaded this drive, the results of which are summarized in Table 6. Owing to the difficulty of human subject research and the variation in response of people with different colored skin, much of the progress in determining the true action spectrum for human skin cancer was done with animal models, especially a genetically constructed strain of hairless mice. It was only in 1994 that a generally accepted action spectrum for photocarcinogenesis was agreed upon (De Gruijl and van der Leun, 1994).

Table 6. Human Skin 1900-2000
it's the Ultraviolet that burnsCharcot, Unna, Hausser…
ultraviolet can tanUnna, Hausser, Vahle…
ultraviolet can cause cancerDubreuilh, Findlay, Roffo, Blum, Urbach…
action spectrum for carcinogenesis
Coblentz, Urbach, Forbes,
Van der Leun, De Gruijl….


Gates and Molecular Biology
In the 1920s, when Hausser's action spectrum for human skin appeared, progress was made on a second front. F. L. Gates at the Rockefeller Institute tested the notion that the shorter the UV wavelength the more effective it was in killing cells. He introduced several important constraints to the field of light research, for example, the importance of ensuring that the target chromophores were exposed to the same fluence from the source. He worked with a layer of bacteria "so transparent that objects may be seen through it clearly and without distortion…" (Gates, 1930). This ensured that the whole sample was exposed to the same fluence of light. Using a monochromator he was able to irradiate samples with wavelengths as short as 225 nm. He noted that the killing effect on a per photon basis peaked in the region of maximum nucleic acid absorption (265 nm), not at 280 nm where proteins absorb most. This was surprising since, at the time, proteins were believed to be the genetic material. But, if they were, why didn't the action spectrum for killing track with the absorption spectrum for protein? Gates, somewhat tentatively, noted that "it has not escaped our attention that nucleic acid may be the genetic material" (Gates 1928). This (along with later results involving cell mutation) was the first clear indication that nucleic acid (later shown to be DNA) was the genetic material. Even so, this notion was not widely accepted by the biological community until the 1940s. But Gates' work also opened the era of utilizing microorganisms to study molecular events that caused cellular response which, in certain ways, led to the development of the field of molecular biology. As Table 7 shows, this line of research was the first to show that DNA was the genetic material, that it was easily damaged (a bit of a surprise), and that it was readily repaired (more surprising). Contributors were many (McLaren and Shugar, 1964; Setlow, 1968 and 1989; Smith and Hanawalt, 1969; Hanawalt, 1989).

Table 7. Molecular Biology
1930's    DNA is the genetic material Gates, Muller, Stadler, Hollander…
1940's DNA is easily damaged  Beukers & Berends, the Setlows…
1950's DNA is readily repaired
  Roberts, Aldous, Setlow, Carrier, Kelner
Rupert, Jagger, Sancar, Hanawalt…
1970's repaired DNA can lead to mutation  Weigle, Devoret, Witkin, Das Gupta…

In addition, molecular biology contributed to the understanding of the molecular basis for human diseases, such as Xeroderma pigmentosum (Cleaver, 1968), launching a photobiologist (Cleaver) to the pages of People Magazine (May 14, 1990), and the National Enquirer (April 26, 1988).


Raab and the Lab Window: Photodynamic Therapy
In 1900 Oscar Raab, working in the laboratory of Van Tappeiner, discovered that certain dyes killed paramecia with greater efficiency in dishes that were placed near the lab window (Raab, 1900). He correctly assumed, and then tested, that it was sunlight streaming through the panes that activated the dye to produce deleterious effects - photodynamic action. This "lab window" effect has been noted several times, including a "re-discovery" of photoreactivation by Kelner in 1949. Meyer-Betz (1913) self-tested photodynamic action when he drank a solution of hematoporphyrin and went out into the sunlight. The dramatic photos of his skin reaction before and after exposure left no doubt that certain compounds could have major photobiologial effects.

Table 8. XP: A Photosensitive Human Disease
1870description of the diseaseKaposi
1889solar radiation is the causePringle
1968due to defective repair of dimers Cleaver
1970complementation groups Kraemer
1991UV induced mutations in p53 gene Brash
1996UV-B and UV-A important Sarasin

This notion quickly passed into the popular literature. Haggard (1939) in " The Light That Kills:" had the protagonists in a memorable short story die writhing in pain after drinking a photosensitizer and then being exposed to the sun at solar noon.

A new Fifth Horseman, clad in the shining armor of a new science,
rode along in the radiant heavens, carrying in his hand a weapon
which no man or beast would ever be able to defy.

But, even into the 1970's reviewers of grants would stated "We all know that light does not penetrate tissues." Recent advances in photodynamic therapy (PDT), like those shown in Table 9, have made PDT more acceptable to the scientific community (Blum, 1964; Spikes, 1985 and 1997; Fritsch, et al., 1998; Bethea, et al., 1999). PDT is now widely used in medicine and further applications are being discovered every year.

Table 9. Photodynamic Treatment
1888 alkaloids plus light kill better  Marccaci
1898 dyes kill better at certain times of day with light from the window
1900 therapeutic potential of PDT  Tappeiner
1913 photosensitizes himself  Meyer-Betz
1940 fundamental theories  Blum
1950 molecular biology and photochemistry  Spikes
1961 uses for tumor detection and therapy  Lipson
1964 role of singlet oxygen  Foote
1978 clinical trials
  Dougherty, Schwartz, Moan, Kato, Kessel, Levy, Hönigsmann


Plants, the First Photobiological Samples
We have already discussed the role of Photobiology in elucidating the function of DNA, but it was studies in the nineteenth century on the chlorophyll in plants that really started the whole field (Coohill, 1989). This last century has seen remarkable progress in the understanding of the molecular mechanisms that underlie photosynthesis (Govindjee, 1982; Deisenhofer and Norris, 1993; Blankenship, Madigan and Bauer, 1995; Loach, 1997). Since 2000, the PSII structure (Zouni, et al., 2001; Kamiya and Shen, 2003; Biesiadka, et al., 2004; Ferraira, et al., 2004; Loll, et al., 2005) and the oxygen evolving complex (OEC- Barber, 2008) have been elucidated. The photoreceptor complex (containing the LH1 and RC) of photosynthetic bacteria has been characterized (Roszak, et al, 2003). Table 10 briefly high-lights the major contributions that have driven the field. The practical implications of this re-search are enormous and underpin efforts to support a burgeoning world population that has more than quadrupled in the last 100 years. This field is so vast that any attempt to summarize it here would be futile. The table below is offered as a minimal attempt.

Table 10. Photosynthesis
1900s    oxygen evolution from plants    Englemann
1930s action spectra Emerson and Arnold
1950s carbon dioxide fixation and reduction pathway Calvin (Nobel Prize), Bassham, Benson
1960s light induced absorbance and EPR changes Duysens, Witt, Chance, Clayton, Commoner, Calvin
  unmasking the reaction center Kok, Clayton, Loach
  chemiosmotic effects Mitchell (Nobel Prize), Jagendorf
  CO2 binding to the RC of PS II, luminescence Govindjee
1970s chemistry of reaction centers Kok, Clayton, Loach, Feher
  four excitations for oxygen evolution Kok, Joliot
  carotenoids protect plants from photosensitization Sistrom, Mathews-Roth, Krinsky
1980s isolation of RCs and light harvesting complexes Reed, Clayton, Gingras,Thomber, Okamura, Feher, Cogdell
  structure of the bacterial RC Michel, Deisenhofer (Nobel Prize)
  electron transport theory Marcus (Nobel Prize)
  time resolved spectroscopy Rentzipis, Windsor, Parson, Shuvalov
1990s B820 subunit of LHs Parkes-Loach and Loach
  reconstitution of LHs Parkes-Loach and Loach, Schmidt and Paulsen
  structure of bacterial LH2 Cogdell and Michel
  structure of PS1 Witt
2000's structure of PSII and OEC Barber, Zouni, Saenger, Kem, Biesiadka, Loll
  photoreceptor cojmplex
(LH1 and RC)


Other Human Exposure
We have already discussed the Photobiology of skin exposure, but two other human responses to light also stand out; the eye and immunology.

A) The Eye - It was expected that light would have great influence on the eye, even beyond that of vision. And indeed, neuroendicrine regulation mediated through the eyes and other photoreceptors is well defined (Kochendoefer, et al., 1999; Brainard, 1998; Brainard and Bernecker, 1996; Klein, et al., 1991; Lam, 1996; Wetterberg, 1993; Birge, 1990; Nathans, 1992). Table 11 lists a few landmarks.

Table 11. Human Vision / Neuroendocrine Regulation
1922    mammalian circadian rhythms synchronized by light    Richter
1950s work with color blind people; light isomerizes rhodopsin Wald, Hubbard, Yoshizawa
1956 mammalian pineal gland receives light input from eyes Quay
1960 light damages the lens Zigman
1965 mammalian reproductive regulation by light Hoffman, Reiter
  mammalian circadian pacemaker located in hypothalamus Richter
1980 light induced melatonin suppression in humans Lewy
1981-1988 role of cyclic GMP in visual signal transduction Stryer
1983 amino acid sequence of opsin determined Ovchinikov, Hargrave
1984 light treatment of seasonal affective disorder Rosenthal
1986 light resetting of human circadian rhythms Czeisler
1986-1989 genes for color vision cloned Nathans
1990 ultra fast photoisomerization of rhodopsin Rentzepis, Shank, Atkinson, Alfano, Callender, Mathies
  transmembrane structure and light induced conformation changes in rhodopsin Yoshizawa, Hargrave, Khorana, Hubbell, Rothschild, Dickerson
1994 time scale of transition of visual pigment is 200 femtoseconds (fastest reaction in all of biology) Mathies, Shank
  chemical mechanism for wavelength regulation in cones Mathies, Sakman

B) Immune Responses - The surprising discovery in the 1970s that ultraviolet radiation caused human immune suppression led to a series of studies looking for the chromophore in skin that causes the response (Kripke, 1986; Noonan and DeFabo, 1992; Duthie, et al., 1999). This phenomenon occurs at lower exposures than those needed to cause erythema (Young, 2000) and may be part of the body's mechanism for not rejecting sunburn damaged cells. With the current focus on allergies in developed countries, it is expected that more will be heard from this field.

Table 12. Photoimmunology
1976    UV alters the immune response preventing rejection of UV tumors Fisher and Kripke, Daynes
1979 UVB is the effective waveband De Fabo and Kripke
1979 UV alters antigen presentation Greene, Stingl, Bergstresser and Streilein
1983 action spectrum indicates UCA photoreceptor De Fabo and Noonan
1986 UV-epidermal cytokines, immunosuppression Schwarz and Luger
1987 Cis-UCA initiates immunosuppression Norval, Howie and Ross, Reeve
1989 UV-DNA lesions, and immunosuppression Applegate, Ley and Kripke
1995-1998 neuropeptide; mast cell involvement Gillardon, Hart.


Bioluminescence occurs in a living organism when part of the energy from a highly exergonic chemical reaction produces a molecular excited state, which is depopulated by the emission of a photon. At first believed to be a bit arcane, this field helped unravel several biological mysteries, including the phenomenon of "quorum sensing," i.e., chemical communication between bacteria. This in turn has led to advances and insights into important areas such as symbiosis and pathogenesis (Harvey, 1952; Hastings and Morin, 1991; Wilson and Hastings, 1998).

Table 13. Bioluminescence
1947    ATP required for firefly bioluminescence    McElroy
1953 flavin required for bacterial luminescence Hastings, McElroy
1961 structure of firefly luciferin White, McCapra
1962 aequorin luminescence in extracts without oxygen triggered by calcium Shimomura, Johnson
1965 chemiluminescence of excited singlet oxygen Khan, Kasha, Seliger
1969 chemiluminescence of dioxetanes and dioxetanones Kopecky, Mumford
1970 autoinduction of bacterial luciferase and quorum sensing Nealson, Hastings
1971 green fluorescent protein and energy transfer in luminescence Hastings, Morin
1983 cloning of bacterial luciferase gene and lux operon Nealson
1986 cloning of firefly luciferase, transgenic expression DeLuca, Wood
1987 the scintillon; cell organelle in dinoflagellate luminescence Nicolas, Hastings
1989 tetrapyrrole structure of dinoflagellate luciferin Nakamura, Kishi, Hastings
1990 structure of green fluorescent protein and cloning of genes Ward, Prasner, Cormier
1992 use of luciferases for reporting gene expression Kay, Wood, Johnson
1995 use of green fluorescent protein as a reporter of gene expression Chalfie


Biological Clocks
Organisms from bacteria to mammals, including humans, respond to periodic illumina-tion by a mechanism of internal clocks (Hastings, et al., 1991; Dunlap, 1996). As prevalent as they are, widespread acceptance of their existence was slow in coming. Due to the pioneering efforts of the individuals listed in the table below, the general public is now well aware of clock biology. Store shelves are full of melatonin, sleep masks are sold in every airport, and shift workers are warned of the disruptions their work schedules may inflict on their lives.


Photomorphogenesis; Photomovement; Blue Light Effects
Although these are separate, and sometimes subtle responses to light, each of the areas listed above is related to the others. Photomorphogenic studies concern the responses of organ-isms, at all levels, to light stimuli. This includes developmental changes, structural adaptations, pigment dispersion and concentration, and growth responses (Kendrick and Kronenberg, 1994;

Table 14. Circadian Rhythms
1935    day-night leaf movement rhythm associated with photoperiodic timing    Bunning
1940 light is the primary synchronizer in daily rhythms Kalmus...
1954 temperature independence of daily rhythms portends a functional biological clock Pittendrigh
1958-1960 phase response and action spectrum for resetting the clock by light Hastings
1969 the pineal as a transplantable oscillator in birds Menaker
1971 clock mutants in Drosophila: the period gene Konopka, Benzer
1972 suprachiasmatic nucleus; the central oscillator in mammals Moore, Zucker
1973 clock mutants in neurospora: the frequency gene Feldman
1985-1995 cloning of Drosophila, neurospora, and synechococcus clock genes; light entrainment of molecular oscillations, feedback model Hall, Rosbash, Young, Dunlap, Loros
1992 suprachiasmatic nucleus transplantation to mammalian host carries phase and period Menaker
1995-1999 clock mutants in mice, characterization of clock genes and proteins Takahashi, Reppert, Schwartz

Table 15. Photomorphogenesis
1940-1960    response of plants to red/far-red light    Bothwick, Hendricks, Hillman, Klein, Toole, Withrows
1960-1970 high irradiance responses of plants Siegelman, Mohr, Hartmann, Mancinelli, Schafer
  purification characterization of phytochrome as the red/far-red reversible photoreceptor Siegelman, Butler, Briggs, Furuya, Schafer
  chloroplast movements mediated by phytocrome; polarotropism Haupt
1960-1980 action of phytochrome in photomorphogenesis Mohr, Quail
1970-1980 characterization and localization of phytochromes Pratt, Furuya
1980 light quality and shade avoidance quantified, Pr-Pfr photoequilibrium Smith
  chemical structure of phytochromobilin and its photoisomerization Ruediger, Lagarias, Song
1980-1990 light-induced conformational changes in phytochromes Pratt, Lagarias, Braslavsky, Schaffner, Song
1985 phytochrome gene family identified Quail, Pratt
  and their functional specificities elucidated Furuya, Quail, Whitelam
1990 phytochrome established as a light switch for circadian rhythms Kay
  molecular mechanisms of phytochrome-mediated light signal transduction Song, Chua, Neuhaus, Quail, Chory, Choi, Song, Nagatami, Schafer, Nagy
1997 bacteriophytochromes discovered in cyanobacteria, and other prokaryotes Lamparter, Vierstra

Table 16. Photomovement
1906    photomovement of ciliate, Stentor coeruleus    Jenning
1960s phototaxis of Eeuglena gracilis Diehn, Lenci, Nultsch
1970 phototropism of phycomyces characterized Lipson, Delbrueck
1979 photophobic and phototactic responses of ciliates characterized Haeder, Poff, Song, Lenci, Matsuoka
1983-1993 rhodopsin-like photoreceptors proposed for phototaxis of Chlamydomonas reinhardtii Foster, Nakanishi, Hegernan
1990 chemical structures of the photoreceptor stentorin Song
  and blepharismin Song, Lenci, Matsuoka

Table 17. Phototropism and Blue Light Effects
1950s    phototropic curvature and auxin translocation related    Briggs
1960s action spectra for phototropism Thieman, Shropshire, Poff
  flavin proposed as the phototropic receptor Galston
1993 Cryl identified as flavin-containing blue light receptor for hypocotyl elongation Cashmore
1990 phototropin identified as flavin-containing light receptor for phototropism; and blue light-activateable autophosphorylating kinase Briggs

Quail, et al., 1995; Wells, et al., 1996; Smith, 2000). Smith (1977) describes the light signals that elicit the metabolic changes required for these responses as "a switching mechanism." Photomovement is a light-mediated change in the configuration of an organism, sometimes including a pattern of growth toward or away from the stimulus (Song, 1983; Spudich, 1991). It includes phototropism, the bending of a growing stem toward light; phototaxis, a movement response in motile organisms; and photokinesis, an increase in response due to an increase in the intensity of the stimulation. Some of these photoresponses (e.g., phototropism and phototaxis) are triggered by wavelengths in the blue region of the spectrum and are called "blue-light effects" (Ahmad and Cashmore, 1996; Briggs and Liscum, 1997). Photomorphogenesis in some fungi is exclusively mediated by a blue photoreceptive pigment. Tables 15, 16 and 17 list this century's advances in each of these areas.


Of central importance to the development of any field is organization (Daniels, 1997). It helps to focus research, allow for cross-fertilization, educates both the scientific community and the public about an area of research, provides visibility and, with a nod to viability, may help in securing government funds. The quadrennial meetings of the IUPB stem from the efforts of a group of European scientists who met in a French bistro over 60 years ago (Latarjet, 1997). And in what may be termed progress (or at least wordsmanship), the group again changed its name in 2000.

Table 18. Organization
1928-1951    Comite International de la Lumiere (CIL)    Saidman, Reyn, Friedrich, Morikofer
1951-1976 Comite International de Photobiologie (CIP) Morikofer, Rajewski, Blum, Hollaender, Meyer, Latarjet
1976-2000 Association Internationale de Photobiologie (AIP)  
2000 International Union for Photobiology (IUPB)  

So far the CIP-AIP-IUPB has held 14 world congresses on photobiology.

Table 19. World Congresses

Number     Year     Location     President     Secretary-General
I     1954     Amsterdam, Holland     Ebbenhorst-Tengbergen, J.W.     Voogd, J.
II     1957     Turin, Italy     Ponzio, M.     Mathi, G. and Benass, E.
III     1960     Copenhagen, Denmark     Christensen, B., Chr.     Buchman B.
IV     1964     Oxford, UK     Bowen, E.J.     Millot, N. and Vince-Prue, D.
V     1968     Dartmouth, USA     Setlow, R.B.     Gordon, S.
VI     1972     Bochum, Germany     Schenck, G.0.     Tronnier, H.
VII     1976     Rome, Italy     Pocchiari, F.     Castellani, A.
VIII     1980     Strasbourg, France     Helene, C.     Charlier, M.
IX     1984     Philadelphia, USA     McElroy, W. D.     Longworth, J. W.
X     1988     Jerusalem, Israel     Riklis, E.     Avron, M., Malhin, S. and Ottolenghi, M.
XI     1992     Kyoto, Japan     Takebe, H.     Ikenaga, M.
XII     1996     Vienna, Austria     Hönigsmann, H.     Dubbelman, T.
XIII     2000     San Francisco, USA     Gasparro, F.     Oleinick, N.
XIV     2004     Jeju, Korea     Song, P-S     Hahn, T-R
XV     2009     Düsseldorf, Germany     Krutmann, J. Organizer    

One scientist who helped greatly in the organization of photobiologists in Europe (especially Britain) was Edna Roe. For her efforts she is recognized at each international meeting by a special lecture.

Table 20. Edna Roe Lectures 1976-2004
1976    Paterson    Canada
1980 Kripke USA
1984 Sutherland USA
1988 Moustacchi France
1992 Völker Netherlands
1996 Chory USA
2000 Barry USA
2004 Bornman Denmark

Concurrently, the San Francisco meeting (2000) was the 28th one for the American Society for Photobiology, an organization almost single handedly started by Smith in 1972 (Smith, 1997). His efforts produced a viable group of photobiologists and may have been the impetus for the beginnings of similar groups in other countries. Indeed, it is easier to identify oneself as a photobiologist if you can point to a society by that name and publish in the journals that spring from those associations.


Left Outs
I will not have to remind the reader that much of the field Photobiology has not been highlighted in this brief review. There are many additional books and review articles that detail the progress of Photobiology. Some of these can be found in the reference pages of the nine articles contained in the symposium "Landmarks in Photobiology" edited by Urbach (1997). Others are cited in the chapters of this and other books and journals.


A Note About the Reference List
It is not uncommon for reference lists in review articles that cover just a portion of any one area of Photobiology to run into the hundreds. I have made no attempt to construct the much longer list that would be necessary for this general historical chapter. Rather, I recommend you to the lists contained in the limited number of reviews I do cite. Also, with some exceptions, I have not cited the original reference for a result but, rather, a review that contains that reference. This allowed for an abbreviated list.


A Note About the Tables
To keep the lists of references to a manageable number, I made no attempt to identify most of the seminal manuscripts associated with the long list of authors.

Acknowledgements - Many photobiologists contributed to this review. The following made detailed recommendations; Brainard, Dougherty, Hastings, Hönigsmann, Jagger, Loach, Noonan, Song, Spikes, Urbach, Valenzeno.

This article was originally excerpted with permission from:
Photobiology for the 21st Century
Thomas P. Coohill and Dennis P. Valenzeno, editors
Valdenmar Publishing Company. Overland Park, Kansas, 2001
and further revised in April 2008


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