TIBS 1 9 - AUGUST 2994

the wide range of sometimes conflicting observations that have been reported'.

As a final comment: it is regrettable that lipids have been overlooked in this book. Not only is fusion basically the mixing of two lipid bilayers, but lipids can also be involved in signal transduction by changing their transmembrane

distribution. For example, in platelets, after the fusion of granules, phosphatidylserine appears on the outer monolayer where it plays an important role as a cofactor in the conversion of prothrombin into thrombin and therefore plays a key role in the blood clotting cascade I.

B00K REVIEWS Reference

1 Zwaal, R. E A., Comfurius, P. and Bevers, E. M. (1992) Biochim. Biophys. Acta 1180, 1-8

PHILIPPE F. DEVAUX

Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France.

How to get spots in front of your eyes

In Situ Hybridization: a Practical Guide

by A. R. Leitch, T. Chwarzacher, 13. Jackson and I. J. Leitch, Bios, 1994. £14.50 (128 pages) ISBN 1 87 274848 1

Over the last decade the technique of in situ hybridization has become a valuable tool for the in vivo visualization of nucleic acids in tissues, cells and chromosomes. The sensitivity of this method has been improved greatly by refinements that have reduced the problems of background noise and nonspecific binding.

This book arose out of a joint programme sponsored by the Royal Society and the British Council to teach the principles and practices of in situ hybridization to the Nanjing Academy of Agricultural Sciences in China. It therefore has a very practical feel about it, and includes sections on the theoretical basis of in situ hybridization and a comprehensive overview of current methods.

This book is aimed at scientists wanting to learn the principles of in situ hybridization, but also at the experienced user who may want to develop new techniques, especially those involving nonradioactive probes. The authors were aware that it is not possible to completely cover the now extensive methodology of this subject in a so-called handbook. Instead, each chapter teases the reader with a compendium of techniques and then finishes with a good initial reading list.

The first chapter concentrates on the types~ of nucleic acid sequences that can be d~tected in prepared samples. This chapter gives a general insight into visualization of low-copy-number and repetitive DNA sequences, chromosome painting and the Iocali~atie'~ ~f I~_NA The figures that accompany the text are well annotated, and are collated from a wide source of different experiments.

Many in situ experiments fail or work inconsistently owing to the inappropriate

preparation and fixation of samples, whether they be animal or plant tissue, cultured cells or chromosomal preparations. This may be due to inaccessibility of the target sequence or inadequate preservation. A chapter entitled 'The Material' highlights the problems of tissue fixation, and the balance that must be achieved in preserving morphology and permeability.

Included in this chapter is the preparation of microscopy slides and electron microscopy grids for samples - a very important step that, if carried out correctly, results in lower backgrounds by preventing the nonspecific binding of probes. The methodology of preparing chromosome spreads from plant and animal sources, tissue sectioning by paraffin embedding and cryofixation are well documented, and complete protocols for these are included. The preparation and fixation of samples varies from tissue to tissue, cell to ceil, and organism to organism. Therefore, in my mind, these protocols should be used only as a general guide to the steps needed for correct preparation. No experiments should be carried out using these methods without extensive prior reading.

The radiolabelling of DNA is well characterized and its principles are covered in other texts. This book takes the opportunity to describe the new methods of labelling with nonradioactive markers. DNA can be labelled nonradioactively using conventional methods, but also by more recent techniques such as the polymerase chain reaction (PCR). One area that has changed a great deal recently is the use of riboprobes for the detection of RNA; nonradioactive labels, such as biotin and digoxigenin, are now widely available. The protocols for the production of biotin- and digoxigenin-labelled DNA and RNA are the highlight of this book and these alone are worth the retail price. In this age of commercial kits, a book that provides the researcher with protocols for tried and tested tailor-made reactions at a fraction of the kit prices is a useful aid.

New signal-generating systems have been developed alongside the

nonradioactive labelling methods. These systems are compared and the reader is guided through which system is the best for his/her needs. Even researchers with experience in the field may find something new in this section, in the descriptions of double labelling methods and the use of fluorochromes. The detection of in situ hybrids has been improved rapidly by these enzyme-mediated systems without any loss of sensitivity, and again the authors point towards these being the way forward for in situ hybridization.

The chapter on imaging and analysis is concise and thorough, which is what you would expect from a book commissioned from the Royal Microscopical Society. Being a self-confessed novice in this area, ! found it a good reference point, and have used the methods for checking fixation already. The sections on the theory of epifluorescence and confocal microscopy are clearly and thoughtfully written and can be digested easily by anyone. Successful photography of slides and sections is very difficult. The maintenance of constant contrast and clarity between samples is of great importance. The short section on this subject discusses the numerous variables that must be considered by the researcher, especially when using fluorochromes or colour precipitates.

I've tried to find faults with this book, and in some cases found them. it is, however, a clear and concise methodological handbook and doesn't pretend to be anything else. ! agree with the authors, that this book is for researchers new and old to this area, and carl guarantee that you will find something of interest. Finally, ! feel that this book may help researchers attempting the technique for the first time in a laboratory where in situ hybridization has never been used. It may help them to step out of the wilderness.

IAN WILSON

Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, UK CB2 1QW.

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