Sex And Death In Protozoa

Is ageing inevitable, or can senescence and death be evaded? Large animals and plants always age if they live long enough; even individual cells from their bodies cannot continue living and dividing indefinitely. Whether or not single-celled organisms also age and die, and what relation sex bore to the process of senescence, was the subject of vigorous debate and experimentation early in the last century. In this book, Dr Bell disinters and reanalyzes these forgotten experiments, and argues that protozoan lineages do indeed senesce, as the result of an accumulated load of mutations that can be shed only through sexual reproduction. This unexpected connection between sex and death is the central theme of a book that will interest all students of evolutionary biology, sexuality and senescence.

Why do we die? Do all living creatures share this fate? Is the body's slow degradation with the passage of time unavoidable, or can the secrets of longevity be unlocked? Over the past two decades, scientists studying the workings of genes and cells have uncovered some of the clues necessary to solve these mysteries. In this fascinating and accessible book, two neurobiologists share the often-surprising findings from that research, including the possibility that aging and natural death may not be forever a certainty for most living beings. André Klarsfeld and Frédéric Revah discuss in detail the latest scientific findings and views on death and longevity. They challenge many popular assumptions, such as the idea that the death of individual organisms serves to rejuvenate species or that death and sexual reproduction are necessarily linked. Finally, they describe current experimental approaches to postpone natural death in lower organisms as well as in mammals. Are all organisms that survive until late in life condemned to a "natural" death, as a consequence of aging, even if they live in a well-protected, supportive environment? The variability of the adult life span--from a few hours for some insects to more than a millennium for the sequoia and thirteen times that for certain wild berry bushes--challenges the notion that death is unavoidable. Evolutionary theory helps explain why and how some species have achieved biological mechanisms that seemingly allow them to resist time. Death cannot be understood without looking into cells--the essential building blocks of life. Intriguingly, at the level of cells, death is not always an accident; it is often programmed as an indispensable aspect of life, which benefits the organism as a whole.

Eukaryotic Microbes presents chapters hand-selected by the editor of the Encyclopedia of Microbiology, updated whenever possible by their original authors to include key developments made since their initial publication. The book provides an overview of the main groups of eukaryotic microbes and presents classic and cutting-edge research on content relating to fungi and protists, including chapters on yeasts, algal blooms, lichens, and intestinal protozoa. This concise and affordable book is an essential reference for students and researchers in microbiology, mycology, immunology, environmental sciences, and biotechnology. Written by recognized authorities in the field Includes all major groups of eukaryotic microbes, including protists, fungi, and microalgae Covers material pertinent to a wide range of students, researchers, and technicians in the field

Kevin Marshall is a hard act to follow. Volume 13 of Advances in Microbial Ecology has been produced by a new editorial board, and we, the members of that board, are delighted to have the opportunity to pay tribute to Kevin's achievements. In his time as Series Editor, the quality of the chapters submitted and the range of subject matter covered have ensured an expanding and more stimulated readership. This represents a considerable achievement, given the growth in the number of review volumes and the increasing tendency for journals to publish review articles. The achievement was reached not only through metic ulous attention to quality and detail but also by providing a forum for the expression of views, information, and results that would stimulate discussion. Advances in Microbial Ecology will continue to provide such a focus, although, because of the frequency of publication, it would not be practicable to introduce a "reply" or "comment" section. Although we do not deliberately aim to provide a forum for controversy, we encourage speculation based on sound scientific arguments. In addition, we would like to encourage authors to offer chapters for consideration. In the past, the volumes have largely comprised invited chapters. With the best will in the world, an editorial board of four cannot claim adequate coverage of such a vast and rapidly developing research area. We would there fore welcome submission of outline plans for chapters, which should be sent to the Editor.

Man's mind stretched to a new idea never goes back to its original dimensions Oliver Wendell Holmes Our current understanding of sex and biological differentiation results from the application of three principal experimental approaches to these subjects: those of the physiologist, the biochemist, and the geneticist. These three approaches are illustrated by the materials presented in the chapters of this volume. Chapters 1-5 emphasize conceptualization of developmental processes, describing systems principally from the standpoint of the physiologist. Structures and functions are defined with only occasional reference to specific molecular details. Chapters 6- 10 present the views of the biochemist, attempting to describe functions influ encing or regulating cellular behavior at the molecular level. And Chapters 11- 14 illustrate the approaches of the modem-day geneticist in his attempts to gain a detailed understanding of processes controlling gene expression. While it is possible to delineate these three major sections, each emphasizing a distinct experimental approach, it must be realized that the yield of knowledge increases exponentially with the number of experimental approaches available to the investigator. Information resulting from the application of each of these approaches must converge to give the same answers for anyone biological phenomenon in anyone experimental system. Further, if we can learn of details regarding a particular process by applying different experimental approaches, our postulates concerning the underlying molecular mechanisms are likely to be more accurate. But biological systems are not unrelated.

Connects classical cellular descriptive studies with more recent work on the molecular and genetic aspects regarding germline development. Prominent scientists discuss research on a range of organisms including insects, worms, birds, fish, amphibia, mammals and green algae. Specification of germ cells, their migration to the gonads and subsequent interactions with the soma and evolutionary factors of their segregation are among the topics covered.

Aging has long since been ascribed to the gradual accumulation of DNA mutations in the genome of somatic cells. However, it is only recently that the necessary sophisticated technology has been developed to begin testing this theory and its consequences. Vijg critically reviews the concept of genomic instability as a possible universal cause of aging in the context of a new, holistic understanding of genome functioning in complex organisms resulting from recent advances in functional genomics and systems biology. It provides an up-to-date synthesis of current research, as well as a look ahead to the design of strategies to retard or reverse the deleterious effects of aging. This is particularly important in a time when we are urgently trying to unravel the genetic component of aging-related diseases. Moreover, there is a growing public recognition of the imperative of understanding more about the underlying biology of aging, driven by continuing demographic change.

Extensively revised and updated to reflect the current state of knowledge in the study of aging, this Fourth Edition offers a complete profile of the aging process at all levels, from molecules and cells to demography and evolution. Written by international experts in current basic and clinical aging research, this text includes aspects of individu