Antibiotics and Antimicrobial Action

Antibiotics and Antimicrobial Action

BIOCHEMICAL EDUCATION July 1978 Vol. 6 No. 3 impressive achievement visually well presented in the film, although not clearly explained. But it does...

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BIOCHEMICAL EDUCATION

July 1978 Vol. 6 No. 3

impressive achievement visually well presented in the film, although not clearly explained. But it does illustrate one of the virtues of a good film: the presentation of techniques and material not readily available to a University teacher.

Insights into Biochemistry Films (Third Review)

3. Determining amino acid sequences in proteins: sickle cell anaemia This film is perhaps the best in the series and will doubtless appeal to those medical students who demand greater "relevance" in their biochemistry course. The application of electrnphoresis and chromatography to the elucidation of the molecular defect in sickle cell anaemia is well described by Vernon Ingrain. A simple treatment of the genetics of the disease incorporates its social relevance, all of which makes for a nice story.

4. Enzymes:catalysts of life processes The lack of any scripting is clearly evident from the unprofessional presentation in this film. The attempt to compare and contrast an enzyme with a traffic cop (sic).would be considered as banal by most teachers and probably by most students also. Why was haemoglobin used to illustrate enzyme-coenzyme interaction? The way in which ATP is stored (sic) in the cell was not clarified; not surprisingly, perhaps. Not even Daniel Koshland can compensate for the poor quality of the film.

5. Enzymes:specialisation and regulation This film highlights all the major defects of the series. Bert Vallec's philosophical introduction is as unnecessary as his habit of looking over his right shoulder every two minutes. The identity of the mystery person in the background becomes as important as the consideration of affinity labelling! The cosy chats by Vailee and Koshland fall to outline the strategy of the film or to emphasise the more significant points.

6. Molecularevolution Richard Dickerson gives a coherent introduction to the subject, which he develops well subsequently, albeit at a fairly simple level, as exemplified by the evolution of cytochrome c. The intervening discussion by Alexander Rich of the molecular basis of mutation borders at times on the trivial. We are inflicted with a description of the double-helical structure of DNA that would probably send most students to sleep. At least, that is the effect which it had on me. M. Carroll Department of Biochemistry The London Hospital Medical College Turner Street London, E1 2AD.

I BOOK REVIEWS

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The six films cover, at a rapid pace, a wide range of topics in protein and enzyme biochemistry. The pictorial presentation and technical aspects of the films are excellent and well known names in biochemistry introduce and develop the subjects. The use of these authorities is to be approved, but the expected impact on students may be reduced, because the status of each lecturer will not be apparent to junior students unless they get this information from their course teachers. Naturally, the experts vary in the effectiveness with which they expand their subjects. Also, one suspects that, in some cases, the experts may not have seen and approved the final (complete) version of each film. Unfortunately, the films are somewhat disappointing from the educational viewpoint. Some are better than others, but they share the fault that each film gives the impression of a continuous essay or discourse in which one topic drifts rapidly into a second and then into a third without any clear separation, headings or summary. This failure to emphasize each important point and not confuse it in the student's mind with other points, means that many students who see the films will gain no permanent benefit from them. In spite of the extensive planning involved in making the films, inadequate attention appears to have been paid to basic educational aspects such as what points are to be emphasized in each film and how are they to be presented so that members of the film audience will grasp each point without confusion. This lack of clear objectives is also apparent when one wonders what grade of student will benefit most from the films. Students with no previous knowledge will still be very confused over many points and students with sufficient knowledge to appreciate the films in their entirety may feel that they have seen nothing new. To illustrate weaknesses on the educational side consider the film, Enzymes, Specialization and Regulation. This dealt with the investigation of active sites (affinity labelling etc.) and with allosteric effects. The discussion by Koshiand was excellent, but the two topics were not sufficiently and clearly separated in the film to avoid confusion for an elementary student. The film on Amino Acids contains statements liable to give rise to difficulties. A confusing reference is made to free energy, and pH is somewhat ambiguously defined as the logarithm of the hydrogen ion concentration multiplied by minus one. The good qualities of the series are exemplified by the film on sickle cell anaemia. Here, beautiful illustrations combine with a clear exposition of the subject ot make this desirable viewing for student audiences. D. G. O'Sullivan Courtauld Institute of Biochemistry .The Middlesex Hospital Medical School London

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Antibiotics and Antimicrobial Action By Stephen M. H a m m o n d and Peter A. L a m b e r t . Being No 90 in the Institute of Biology's Studies in Biology. Edward Arnold (Publishers) Ltd., London. 1978. Pp 64. Boards £3.20, p a p e r , £1.50. This book achieves the object of the series, of which it forms a part, to present a readable account of advances in biological science suitable for use in schools and colleges. Thus a brief introduction to the production of antibiotics and their sites of action in microbial cells is followed by an account of methods used in detecting their antimicrobial activity and more detailed accounts of the principal mechanisms involved in such action. Distinction is drawn between an antibiotic as an antimicrobial agent produced by another living organism and synthetic drugs which may have similar actions. The

book is primarily concerned with the former but the latter are occasionally referred to, for example the detergent action of antiseptics on membranes and the antifolates. The mechanisms of action are normally clearly shown by a combination of diagrams and chemical structures, but it is surprising to find in giving the structure of penicillin that attention is not drawn to the structural similarity between part of this molecule and part of the structure of non-crosslinked peptidoglycans as a basis for the inhibition of the crosslinklng transpeptidase. It is perhaps more serious that no mention is made of the binding of penicillins to other bacterial proteins which forms the basis of the preferential action of amidinopenicillin (mecillinam) against Gram negative bacteria and that polymyxins only disrupt membranes containing phosphatidyl ethanolamine and not other phospholipids. The bibliography is brief but valuable and refers readers to several texts which contain more detailed accounts of the subject matter. F. W. Chattaway