Biotechnology & genetic engineering reviews. Volume 1

402

Reviews

of recent

publications-

The book is divided, into four sections. The first section covers general aetiological factors-genetic and environmental-and their relative importance in the various types of cancer. This includes an excellent review of our current knowledge on the causation of gastric and colorectal cancer by Michael Hill, who also expounds his own hypothesis on the mechanism for the histopathogenesis of colorectal cancer. The second section deals with precancerous lesions of the oesophagus and stomach. This includes experimental studies on pathogenesis. epidemiology and high-risk conditions such as pernicious anaemia, chronic atrophic gastritis and gastric polyps. Markers of high risk and surveillance techniques are also covered. The small intestine and colon are dealt with similarly in the third part of the volume. Finally, two papers dealing with the principles and methods of screening for precancerous conditions complete the volume. In any compilation of papers from a symposium there is bound to be a certain element of repetition and lack of structure, but on the whole these papers combine to form a very informative and very readable review of many aspects of gastro-intestinal cancer and its precursor lesions. It should be of value to anyone with a broad interest in gastro-intestinal disease and cancer-linicians and research workers alike. It should also provide food for thought for those interested in the role of nutrition in cancer, the point being made that, in the study of the causation of gastric and colorectal cancers, the major dietary components that are positively correlated with cancer at one site are inversely correlated with cancer at the other site. Human

Intestinal

Microflora

in Health and Disease.

Edited by D. J. Hentges. Academic Press,New York. 1983. pp. xvii + 568. f47.50. In its twenty chapters, this book reviews factors influencing the composition, development and metabolism of the human gut flora and its relationship to the host. Direct data are given whenever possible. yet many practical limitations are imposed on the investigator in collecting a ‘representative’ sample of material from the intestine-the Heisenberg uncertainty principle as applied to microbiology! Having said this, the volume does not rely unduly on animal studies, which are only described in the absence of suitable human data or where they apply directly to the human condition. The opening chapter by S. M. Finegold and coworkers introduces the reader to some of the problems that abound in the highly complex isolation and identification of human gut organisms. Comprehensive tabulation of the several hundred organisms that are found in the ‘normal’ human is given, yet the underlying inter-individual variation (perhaps reflecting differences in race, diet or age) emphasizes the constant uncertainty present in such taxonomic investigations. Subsequent chapters describe factors that control the gut microflora, such as the dynamics of bacterial growth (R. Freter), the colonization of epithelial surfaces (D. C. Savage)and the host immune response (R. D. Berg). Changes in

the balance between the competing members of this ecosystem. or between the microflora and the host, may result in a number of clinical manifestations associated with the pathological colonization of the gut mucosa. For example, antibiotic treatment is associated with the infrequent (but potentially severe) occurrence of pseudomembranous colitis (reviewed by J. G. Bartlett). while bacteria or bacterial products play an essential part in the aetiology of ulcerative colitis (reviewed by A. B. Onderdonk). On the positive side, however. the intense competition for nutrients and niches within the healthy gut flora plays an important role in resistance to colonization by pathogenic organisms (reviewed by D. J. Hentges). The metabolic activities of the intestinal bacteria are also reviewed. They cover bacterial intermediary metabolism in the gut as well as the microbial transformation of acid and neutral sterols and xenobiotic substrates. Fermentation of complex dietary carbohydrate, such as plant cell-wall material, makes a major contribution to the bacterial energy pool and is considered by A. A. Salyers & J. A. Z. Leedle, and M. J. Wolin & T. L. Miller. Direct studies of this type in the human are still in their infancy, yet hydrogen, methane and short-chain fatty-acid production appear to be similar in man and other mammals. A further important factor controlling bacterial growth is the provision of endogenous nitrogen-containing products occurring in the human hindgut (R. B. Hespell & C. J. Smith). The biotransformation of acid and neutral sterols by the gut bacteria is covered in two comprehensive chapters (P. B. Hylemon & T. L. Glass. and V. D. Bokkenheuser & J. Winter) which identify the major organisms. substrates and bacterial products. A more general overview of the biochemical pharmacology resulting from microbial attack of xenobiotic compounds is given by P. Goldman, along with some important examples of microbial activation and deactivation of such substrates. The final contribution on bacterial biotransformation activities comes from T. D. Wilkins & R. L. Van Tassel], who describe the identification and potential sources of mutagenic activity present in human faeces. This book is recommended as an important contribution in the field of host/gut flora interaction, particularly on the role of the hindgut bacteria in the development of certain pathological or toxicological events. Biotechnology

&

Genetic

Engineering

Reviews.

Volume I. Edited by G. E. Russell. Intercept. Newcastle upon Tyne. 1983. pp. x + 438. f40.00. Biotechnology is one of the oldest of the applied sciences,dating back to the ancient Sumerians and their determination of the ideal conditions for brewing beer. However, with the advent of recombinant DNA technology, the popular view is that biotechnology is only about the insertion of foreign DNA into micro-organisms in order to produce an expensive compound cheaply. This is unfortunate. since biotechnology is becoming increasingly diverse-a point admirably demonstrated in the volume identified above.

Reviewsof recentpublications--Fd C/tern.To&. Vol. 23. no. 3 Gordon Russell has collected 13 review articles on a wide range of topics by leading experts from many parts of the world. These cover five major areas: enzymology. genetic manipulation, environmental control and the application of microbes to commercial processesand safety. The opening contribution is by S. L. Neidleman, who emphasizes the importance of enzymes in biotechnology, and the variety of conditions and techniques used in a wide range of industrial applications of enzymes. These applications include the production of food components and the control of organoleptic properties, inclusion in detergents, use in diagnostic or analytical tests, the production of digestive acids for medical purposes and the treatment of waste. The following contribution (by T. Harada) concentrates on the production of sugars such as glucose or maltose from starch using debranching enzymes such as isoamylase. The volume also includes a chapter on genetic engineering and nitrogen fixation by J. E. Beringer 8~ P. R. Hirsch, who discuss the introduction of nitrogen-fixation genes into rumen bacteria. This is followed by a review on biosensors and biofuel cells: W. J. Aston & A. P. F. Turner discuss “the art of coupling biological systems with electrochemical techniques”. H. Y. Neujahr expands on this with a look at the application of biosensors to the detection of pollutants such as pesticides and heavy metals. Further contributions include reviews of the use of viruses as pest-control agents (J. B. Carter), aerobic and anaerobic treatment of sewage (A. D. Wheatley), the use of immobilized enzymes in the manufacturing industries (P. B. Poulsen), the health risk associated with microbiological research (C. H. Collins), the injection of micro-organisms into oil-bearing rock in order to enhance oil recovery (D. E. Springham), the potential of sugar-cane as a source of high-grade fuels (J. Coombs) and the development of enzymatic processing of cheese whey for the production of food yeast. ethanol, hydrolysed lactose and other products (G. Moulin & P. Galzy). All of the articles are well written, have excellent bibliographies and provide the reader with concise yet detailed reviews of particular aspects of biotechnology. The standard of editing complements the high standard of the contributors and has led to the provision of an excellent index. One initial disappointment with this book stemmed from the absence of any chapters on the commercial applications of mammalian and plant tissue cultures-and there is no chapter on the recent developments in recombinant DNA technology. However, these deficiencies will apparently be remedied by the contributions to subsequent volumes, which suggests that this series of reviews could prove to be an invaluable buoyancy aid for scientists and industrialists who wish to remain afloat on the rising tide of biotechnology.

403

Culture of Animal Cells: A Manual of Basic Technique. Edited by R. I. Freshney. Alan R. Liss, Inc., New York, 1983. pp. xiv + 295. E38.00. The value of cell-culture techniques for the study of the effects of chemicals at the cellular level has been appreciated for many years. Much useful information about the mechanisms of action of toxic chemicals has been gained by the use of specific cell types maintained under carefully controlled conditions. However, as a means of assessingchemical hazard to man, these methods have severe limitations. The vulnerability of isolated cells, the unphysiological nature of their environment and the absence of the complexities of organization found in the whole animal are factors that discourage attempts to predict the likely effects of a chemical in uiuo on the basis of cell-culture data. In certain cases,such as the detection of mutagenic/carcinogenic potential, determined efforts to validate empirically the results of cell-culture tests, using results obtained from animal experiments, have met with some success.As public distaste for animal experimentation intensifies in concert with rising economic pressures, interest in cell-culture techniques as alternatives to the use of animals is certain to increase. More toxicologists will ask how cell systems can best be employed and how the techniques can be introduced into their laboratories. The answer to the first question might reasonably be sought in Cellular Systems for Toxicity Testing, which contains the proceedings of a conference held in October 1982. The content of the book is indeed an accurate reflection of the current status of cell culture systems in chemical safety evaluation. Unfortunately, this means that there is an overwhelming bias towards the detection of genetic effects and cell transformation. Only a handful of the 37 main papers deal with other aspects of toxicology. The possibility of using cell-culture methods to detect effects such as neurotoxicity, irritancy and immunotoxicity is touched upon in a few of the short (2-3 page) poster papers. In general, the book is well presented, clear and authoritative. Valuable reviews of test systems for DNA damage, chromosome effects, mutation and transformation include much that is new. This book is a useful contribution to the genetic toxicology literature disguised as a more general discussion of cell-culture techniques in toxicology. Culture Techique

of Animal

Cells:

A Mwlual

of

Basic

is exactly what it claims to be. An attractive, clear and well-illustrated volume, it provides all the instructions required for a complete novice to embark on what may sometimes appear to be a difficult technology full of mystique. It is particularly refreshing to find advice on minimal requirements for small-scale facilities, given without condescension, alongside information on more advanced and expensive equipment and laboratory designs. The approach is typified by the classification Annals of the New York Academy of Sciences, of equipment as either essential, beneficial or useful. Volume 407. Cellular Systems for Toxicity Testing. Basic techniques are described in detail, illustrated Edited by G. h4. Williams, V. C. Dunkel & V. A. Ray. with diagrams and presented in the form of a simple The New York Academy of Sciences, New York, set of instructions. A good selection of more 1983. pp. xi + 484. 895.00. specialized techniques is covered in outline. This is