ESP newsletter

Journal ofPhotochemistry

and Photobiology,

B: Biology, 5 (1990)

127 - 130

127

ESP NEWSLETTER Editor: Giuliana Moreno Laboratoire de Biophysique, INSERM U 20 1, CNRS UA 48 1 Museum National d’Histoire Naturelle 43 rue Cuvier, 75231 Paris Cedex 05, France Telephone: (1)43 3107 34 Fax: (1) 45 35 70 72

NO. 17 April

1, 1990

“IN THIS ISSUE OF JPB” MOVES TO THE FIRST

PAGE OF JPB

The readers have surely noticed that “In this Issue of JPB” has moved from the ESP Newsletter to the first page of JPB. It seems logical to start the issue of JPB with this section instead of placing it at the end, and in this way more space will be available for commenting on the selected papers. I am pleased that this section is moving along and I am very grateful to Alessandra Andreoni for having undertaken this difficult editorial job which I am sure she will continue to develop well for our readers. GIULIANA

BRIEFING OUTSIDE Photocarcinogenesis

MORENO

JPB

The most important recent development in the field of UV carcinogenesis is undoubtedly the induction of malignant melanomas in animals by UV irradiation and this time the results seem to be reproducible! The two animal models concerned are rather exotic: a platyfish-swordtail fish hybrid (Woodhead et al., 10th Int. Congr. on Photobiol., abstract, p. 32), and an opossum (Monodelphis domestica) (Ley et al., Photothem. Photobiol., 50 (1989) 1 - 5). Firm experimental proof for the UV-induced transformation of melanocytes into malignant cells has been lacking until now. The longstanding idea that melanomas in man are somehow causally related to solar UV radiation has gained credibility substantially. Quite a few scientists may have quietly and stubbornly spent their time on “long shots”, making heroic attempts to induce UV melanomas in all sorts of ways (despite the financial pressure for guaranteed success in research). I know of several (as yet) unpublished, unsuccessful attempts; I think they should be published (brief communication/research note) in order to guide others in their attempts. The question is whether it is just harder to induce UV melanomas in the commonly used mice, or whether it is really impossible. Maybe the opossums and fish are somehow predisposed to UV melanomas. Is it a mere coincidence that both species are proficient in photo-repairing pyrimidine dimers? Despite the peculiarity of the fish and opossum models, they clearly show that melanocytes can transform into cancerous cells under UV irradiation. Another recent indication that solar UV radiation is contributing to the pathogenesis of cutaneous malignant melanoma comes from a study of N-ras mutations (Van’t 0 Elsevier Sequoia/Printed

in The Netherlands

128 Veer et al., Mol. Cell Biol. 9 (1989) 3114 - 3116). It was found that N-ras mutations occurred exclusively in tumors (non-lentigo malignant type) from continuously exposed skin sites (in seven out of ten tumors from these sites). The complementary sequences to the altered codons all contain pyrimidine doublets: potential UV-induced dimer sites. FRANK R. DE GRUIJL,

CONFERENCE

Dermatology,

State University of Utrecht, The Netherlands.

REPORTS

International Symposium on Photobiology and Biotechnology (Poznan, Poland, June 27 - 30, 1989) This symposium, held at the Poznan Technical University, was organized by the Poznan Technical University (Institutes of Physics and Environmental Health) and the Poznan Academy of Economics (Institute of Commodity Science). It was financially supported by the Ministry of National Education and the Office of Environmental Protection. The meeting brought together over 150 scientists and students from 19 countries from eastern and western Europe, and from the U.S.A., Canada, Israel, China, New Guinea and Japan. The aim of the symposium was to discuss the applications and further perspectives of photophysical and photobiological methods in the fast expanding field of biotechnology. This was achieved by a series of 38 invited lectures/surveys, short contributions, informal round tables and poster sessions. Many young scientists had the opportunity to present their recent results for the first time. The programme was divided into 5 sessions. Solar energy conversion. Solar energy utilization via the cultivation of halotolerant algae for products of commercial interest as well as all stages of carotenoid production starting from cultivation and ending with the packaged drug commercially available today, were presented by M. Avron (Israel). G. Renger (F.R.G.) discussed the biological exploitation of solar energy by photosynthetic water cleavage in cyanobacteria and plants. H. Ti Tien (U.S.A.) described the method recently developed in his laboratory for hydrogen production from water by semiconductor septum electrochemical photovoltaic cells. The possibility of conversion of solar energy into electricity using artificially ordered photosynthetic pigments in monolayers was reviewed by S. Hotchandani (Canada). Environmental photobiology. This session dealt mainly with the protection of the natural environment. Reports on the influence of chemical and physical agents on living organisms, and the methods of detection and neutralization of pollution, were given in several lectures. L. 0. Bjijrn (Sweden) proposed an interesting method of monitoring plant condition by the detection of ultraweak plant tissue luminescence. P. D. Hansen (F.R.G.) discussed the effect related to bioassays-ecotoxicological testing with a luminescent bacteria assay. The regulation of photosynthetic apparatus under various environments was reported by Y. K. Shen (China). Photoreceptors in photobiology. Photoreceptors were the main topic of this session. A comprehensive overview of the numerous functions of phytochrome in plants and of another sensor - stentorin - in an aneural unicellular protozoan ciliate Stentor coeruleus was presented by P. S. Song (U.S.A.). Other reports dealt with the role of different biological systems (pigments, enzymes, lipids), their function and mechanism of action. Spectral methods in photobiology. A variety of spectroscopic methods were reviewed during this session. A microchannel-plate photomultiplier and its application to the single-photon timing technique was described by I. Yamazaki (Japan). S. Braslavsky (F.R.G.) presented fast photoacoustic methods developed in her laboratory for direct measurements of heat evolution of the short-lived species produced by light excitation.

129 S. Malkin (Israel) considered photothermal radiometry measurements in photosynthesis, particularly the light distribution between the two photosystems, its variation, control and monitoring of plants under stress. The instrumentation and biochemical application of frequency-domain fluorescence spectroscopy was discussed by J. R. Lakowicz (U.S.A.). The application of optically detected magnetic resonance and other magnetooptic methods in structural and energetic investigation of the photosynthetic apparatus was reviewed by A. J. Hoff (The Netherlands). Photobiotechnology trends. D. 0. Hall’s lecture given by W. P. Williams (U.K.) on fuel and chemical production by immobilized photosynthetic bacteria stimulated a great interest. Another report in this field dealt with the application of ion-permeable cyanobacteria as photoreducing biocatalysts (G. C. Papageorgiou, Greece). Perspectives of applying photobiology to biotechnology were discussed during a round table where M. Avron indicated the potential applications of photobiology for the future: the first of medical interest, in diagnosis, skin and cancer therapy; the second, in fuel and electricity production. Environmental protection and its monitoring should be carried out by groups of scientists from different countries working in collaboration. The majority of lectures, contributions and posters are published in a book available from the symposium organizers, Poznan Technical University, U.S. $20, Bank Account: NPB III o/m Poznan 63034-10298-151-4787 “Symposium 89”. HENRIK MANIKOWSKI,

Institute of Physics, Poznan Technical University, Piotrowo 3, 60-965 Poznan, Poland.

EPA Summer School on Photochemistry on “Light and Pharmaceutical Chemistry” (Spiez, Switzerland, July 30 - August 5, 1989) The 6th EPA Summer School 1989 on “Light and Pharmaceutical Chemistry” in Spiez was organized by the Swiss section of the European Photochemistry Association in cooperation with the InterAmerican Photochemistry Society (IAPS) and the Japanese Photochemistry Association (JPA). It was the first one in Switzerland as well as the first one of the EPA dedicated to interdisciplinary photochemical research located somewhere between biology, chemistry, medicine, physics and toxicology. There were 76 participants coming from all parts of the world (20 countries) and having different research interests with respect to academia as well as industry. In the first lecture of the Summer School, K. Tokumaru (Japan) introduced the participants in the Basic Principles of Photochemistry: the observation of the excited states and importance of electron transfer and isomerization processes in photochemical reactions. W. Adam (F.R.G.) and G. Cilento (Brazil) talked about Endogenous Photochemistry, a new branch of photochemistry/photobiology in which the effects of generated excited states on cell and/or organelles are investigated. They discussed the types of chemical generation of excited states, the synthesis of dioxetane-labelled biomolecules, excited states produced by the cell machinery when challenged with appropriate substrates (pharmaceuticals, polluants), and the effects produced by these excited species. In the presentation of I. Saito (Japan) on Recent Aspects of the Photochemistry of Nucleic Acids and Proteins, results on the chemical aspects of photo-crosslinking of DNA to proteins and the photoinduced DNA nicking reactions were covered. The design of photochemical DNA cleaving molecules (“artificial photonucleases”) was also described. The lecture of R. S. Davidson (U.K.) on Principle of Fluorescence Zmmuno-Assays introduced the audience to the methods for quantitating materials by using fluorescence, phosphorescence, and chemiluminescence as a means for detailing and quantifying biologically active materials. In their talk on The Photochemistry of the Eye, J. Dillon (U.S.A.) and J. Roberts (U.S.A.) examined the implications of ambient irradiation impinging on the human eye and its possible role in aging and senile disease process in that organ.

130 I. E. Kochevar (U.S.A.) showed in her lecture Phototoxicity of Drugs that it is important to study phototoxicity mechanisms to predict phototoxicity of drugs being developed and to design drugs for phototherapy and cell biology. Several mechanisms for drug phototoxicity and their relevance were discussed. In a very well illustrated lecture on Photodermatology - Clinical Aspects, N. Mizuno (Japan) showed that the adverse effects of light on the skin are acute and chronic damages of the normal skin, photodermatoses due to exogenous substances, and endogenous dermatoses. H.-U. Gonzenbach (Switzerland) started his lecture Principles of Photoprotection with a video. Then UV light and its effects were discussed followed by an explanation of the sun protection factor and the structures and spectra cosmetic UV-absorbers. After the presentation of the requirements for an ideal sunscreen, nobody wondered why no new sunscreen has been introduced for more than a decade. I. Cabrera (F.R.G.) showed in his lecture Photochemistry ofMembrane Aggregates what can be done with photochemistry in self-organized systems. Although the investigations have not yet progressed to the point of modelling closely photobiological processes, it is reasonable to believe that some of the changes described may have real analogies in biological systems. In the concluding lecture of the Summer School, D. De Keukeleire (Belgium) fascinated the audience with his favorite topic: Photochemistry ofBeer. Including experiments and tasting a few beers selected from 734 Belgium breweries, he showed that photochemical manipulations are useful in hop and beer chemistry to create new bitter tasting and flavoring compounds from less valuable substrates, thereby enhancing favorably the beer aroma. In practice, the most important effect of light on beer is the instantaneous development of the lightstruck flavor due to photochemical formation of 3-methyl-2-butene-1-thiol. The presence of this thiol, even in minute quantities, is deleterious for the beer quality. Therefore, on hot and sunny days D. De Keukeleire recommends to drink the beer quickly. In addition, a workshop on Photodynamic Therapy (PDT) was organized by T. Vidoczy (Hungary). During the week there were exhibits of two posters on Vitamin A and Vision by J. Gmiinder and C. E. Reily (Switzerland), and on Photochemical Equipment by H. Mangels (F.R.G.). The lecturers have undertaken the challenging task to prepare abstracts of their lectures, which have been collected in an excellent workbook. This book is available for SFr. 30 from Dr. T. Oppenllnder, F. Hoffmann-La Roche Ltd., Central Research Units, Building 65/607, CH-4002 Basle, Switzerland. After this very stimulating and successful Summer School, the Swiss members of the Organizing Committee would like to have a follow-up “Summer Camp” at the ACCenter at Spiez and establish such meetings every second Summer under the general heading of Light in Biological Systems. BRUNO FREI, Ciba-Geigy Ltd., Basle, Switzerland. THOMAS OPPENLANDER, F. Hoffmann-La Roche Ltd., Basle, Switzerland.

POSTDOCTORAL

POSITION

Applications are invited for a postdoctoral fellowship to work with Dr. R. J. H. Davies on the detection and characterization of DNA damage induced by environmental and pulsed laser ultraviolet radiation. The fellowship is available for one year, with the possibility of extension: salary 8 11000 to 2 16 000 according to age and experience. Please send curricuEum vitae including names and addresses of two referees to: Dr. R. J. H. Davies, Biochemistry Division, Queen’s University, Belfast BT9 7BL, Northern Ireland. Telephone enquiries to Dr. Davies at Belfast (0232)329 241 extension 2701.