Molecular Photobiology

Molecular Photobiology: Inactivation and Recovery describes the deleterious photochemical reactions occurring in biological systems. This book is composed of 10 chapters that specifically tackle light interactions in the ultraviolet region of the spectrum resulting to damaged proteins and nucleic acids in living systems. This book deals first with the kinds of photochemical reactions that can occur and the possible effects of photochemistry on molecular, cellular, and organismal levels. The succeeding chapters highlight the principle of recovery mechanisms, wherein evidence shows that cells can repair their damaged genetic material, and thus recover from the otherwise inactivating effects of light. The remaining chapters are devoted to the comparison and contrast of some biological effects of ionizing radiation and those of ultraviolet radiation. This book is of value to molecular photobiologists, photochemists, biochemists, and radiation scientists and researchers.

Sunscreens are universally recommended by dermatologists not only to prevent the immediate effects of overexposure to sunlight but also to prevent skin cancer. While the former goal is immediately evident, the latter remains an unproven hypothesis and is a topic of some controversy. Recent epidemiological studies suggesting a correlation between increased use of sunscreens over the past two decades and the rise in skin cancer have led to the question whether sunscreens applied to skin may be undergoing photoreactions, the effects of which are elaborated many years later. By addressing the key questions, this book advances the field of sunscreen photobiology and provides the reader with an unbiased perspective on this important field.

Photochemistry and Photobiology of Nucleic Acids, Volume I: Chemistry covers the historical developments in the study of photobiology and photochemistry of nucleic acid components. This volume is divided into 12 chapters that deal with the isolation and characterization of ultraviolet photoproducts of pyrimidines. After briefly covering the concepts of photochemistry of nucleic acids, this volume goes on describing the UV-induced physical and chemical alterations in nucleic acid components, such as pyrimidines, purines, their nucleosides and nucleotides, and related compounds. Significant chapters are devoted to mass and nuclear magnetic resonance spectrometry and crystal and molecular structure determinations by X-ray diffraction. Together with the pertinent examples, a short discussion on the theory and techniques is also presented in each chapter. This volume also includes a chapter on radiation chemistry to examine the close relationship between the chemical effects of UV-light and X- or gamma-radiation. This volume is of value to researchers who are active in the study of photochemistry and photobiology in nucleic acids as well as to advanced undergraduate and graduate students interested in this field.

It is not always the case that the subject of a scientific book and its relevance to everyday li fe are so timely. Photobiology and its si ster subject Radiobiology are now a must for understanding the environment we live in and the impact light, ultraviolet light, and radiation have on all aspects of our life. Photobiology is a true interdisciplinary field. Photobiology research plays a direct role in diverse fields, and a glance at the topics of the symposia covered in this book by over 100 articles shows the breadth and depth of knowledge acquired in fundamental research and its impact on the major issues and applied problems the world is facing. Half a century of photobiology research brought about an understanding of the importance of light to life, both as a necessary source of energy and growth as weIl as its possible dangers. Research in photochemistry and photobiology led to the discoveries of ceIlular repair mechanisms of UV induced damages to DNA and this led to understanding of the effects of hazardous environmental chemieals and mutagenecity , and to the development of genetic engineering. This topic was given due emphasis in several symposia and chapters in this book.

Man has recognised an association of light with life and medicine for over 3000 years. Today the major challenges to this topic include the elucidation of photochemical reactions involved in photobiology at the molecular level. This includes the use of a variety of modem probing techniques that directly measures the reactivity of excited states and free radicals involved in biological reactions. This text-book is based on such an approach and has arisen from some of the lectures delivered at the NATO ASI held at Hotel Capo Caccia near the Centre for Advanced Research in Photobiology (CARP) in Sardegia, Italy. The ASI took place from 30 September -13 October 1993 and involved a total membership of 90. The book, like the NATO ASI itself, is divided into four themes starting with fundamental aspects and ending with complex medically related systems. Thus Theme 1 covers aspects of the underlying photophysics and photochemistry with particular emphasis on modem experimental techniques to study molecular mechanisms of biological processes. Theme 2 applies many of these fundamental studies to the chemical reactions of most relevance to photobiology and photomedicine such as photo-addition, -isomerization, -sensitization and -pigmentation. The third and fourth Themes deal with the deleterious and therapeutic aspects of light with particular emphasis on the use of Photo-Dynamic Therapy (PDT) to treat cancer and on viral and micro bioi infections.

Comprehensive Biochemisty, Volume 27: Photobiology, Ionizing Radiations deals with the aspects of bioenergetics, immunochemistry, photobiology, and molecular phenomena that underlie the evolution of organisms. This book discusses the types of phototropic response, action spectra in the further ultraviolet, and structure and light-absorbing properties of the photoreceptor cells. The preliminary remarks on visual pigment structure, synopsis of extracted systems, oxidation of proteins, and effects of ultraviolet radiation and photoreactivation are also elaborated. This text likewise covers the chemical nature of photoreactivable damage, reversibility of potentiated flowering response, and primary reactions in algae and higher plants. This volume is beneficial to biochemists and specialists researching on ionizing radiations.

This is the first volume of new book series on biophysics and biocybernetics, initiated by the Istituto Italiano per gli Studi Filosofici.A main problem in biophysics is the interaction of light information with functional living structures, in order to shape the organism's behaviour. Although the processes of photoreception and phototransduction are articulated in various ways in different living beings — as it is seen in the subdivision of the topics in this volume on microorganisms, invertebrates, and vertebrates — general ways of light signal reception and transduction through light energy, i.e., photosensitive molecule interactions, could be observed. Highly sophisticated advanced techniques are employed in this research field.