Structure And Ultrastructure Of Microorganisms

Structure and Ultrastructure of Microorganisms: An Introduction to a Comparative Substructural Anatomy of Cellular Organization presents the structure or principle of operation of the electron microscope. This book provides an introduction to the submicroscopical anatomy of the cell in ultrathin sections of tissues or of single-cell organisms. Organized into 30 chapters, this book begins with an overview of the structures discovered by the use of an optical tool for observation. This text then examines the anatomical principle to the nucleus. Other chapters consider the structural organization of chromatin as revealed in electron micrographs of thin sections through cells in different stages of division. This book discusses as well the macronuclei of the ciliates, which plays a significant part in the reproductive mechanism. The final chapter deals with the micromolecular organization of bacterial flagella. This book is a valuable resource for scientists, biologist, physicists, protozoologists, cytologists, biochemists, biophysicists, and research workers.

The modem microbiologist is often a real specialist who has difficulty under standing and applying many of the techniques beyond those in his or her own immediate field. On the other hand, most benefits to modem microbiology are obtained when a broad spectrum of scientific approaches can be focused on a problem. In early studies, electron microscopy was pivotal in understanding bacterial and viral morphology, and we still feel that we will understand a disease better if we have seen an electron micrograph of the causative agent. Today, because there is an increased awareness of the need to understand the rela tionships between microbial structure and function, the electron microscope is still one of the most important tools microbiologists can use for detailed analysis of microorganisms. Often, however, the aforementioned modem microbiologist still thinks of ultrastructure as involving negative staining or ultrathin sectioning in order to get a look at the shape of a "bug. " Many of the newer ultrastructure techniques, such as gold-labeled antibody localization, freeze-fracture, X-ray microanalysis, enzyme localization, and even scanning electron microscopy, are poorly under stood by, and therefore forbidding to, the average microbiologist. Even many cell biologists admit to having difficulty staying in touch with current develop ments in the fast-moving field of electron microscopy techniques.

Studies of the bacterial cell wall emerged as a new field of research in the early 1950s, and has flourished in a multitude of directions. This excellent book provides an integrated collection of contributions forming a fundamental reference for researchers and of general use to teachers, advanced students in the life sciences, and all scientists in bacterial cell wall research. Chapters include topics such as: Peptidoglycan, an essential constituent of bacterial endospores; Teichoic and teichuronic acids, lipoteichoic acids, lipoglycans, neural complex polysaccharides and several specialized proteins are frequently unique wall-associated components of Gram-positive bacteria; Bacterial cells evolving signal transduction pathways; Underlying mechanisms of bacterial resistance to antibiotics.

Mter the discoveryof the tobacco mosaic virus by D. I. Ivanov skU in 1892 [14], the new science of virology was born and began to develop rapidly. The number of viruses now known is enormous and they can infect nearly all animal and plant organisms. Microorganisms themselves are no exception to this rule. Despite intensive study of Vlruses, their origin and nature are still a subject for speculation and hypothesis. The general concept of viruses embraces a wide group of biologically active structures occupying an intermediate position between living and nonliving matter. The dual character of viruses is determined by the fact that, while they do not possess an inde pendent system of metabolism, which is a characteristic feature of every living being, they nevertheless carry within themselves all the necessary information for autoreproduction. A striking feature of the virus is that it consists essentially of two components: a protein envelope and the nucleic acid con tained within it. In contrast to the elementary structural unit of the living or ganism, the cell, which contains two types of nucleic acid (DNA and RNA), the virus particle contains only one type of nucleic acid - either DNA or RNA. It is perhaps this which is responsible for the imperfection of the virus as a living organism.