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Book Review Crop Protection Agents from Nature. Natural Products and Analogues. Edited by L. G. Copping

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Explosive Topics for Specialist and Novice
RNA. (Series: Nucleic
Acids a n d Molecular Biology. Vol.
10.) Edited by E Eckstein and
D. M . J. Lilley. Springer, Berlin, 1996.
41 7 pp., hardcover DM 248.00.-
ISBN 3-540-60795-1
There can scarcely be any other area of
science that has undergone such an explosive phase of development in recent years
as the chemistry and biochemistry of ribonucleic acids. Up to the beginning of
the 1980s the only biopolymers regarded as
having catalytic properties were proteins.
However, the first published reports of
catalytic RNAs stimulated numerous investigations, which have subsequently led
to the identification ofcatalytic RNA motifs in various organisms, and to the development of combinatorial strategies for the
evolution of artificial catalysts. The development of this branch of research has extended the study of biochemical catalysis
to a hitherto unexplored system, provoked speculations about the origins of
life in a prebiotic “RNA world”, and introduced the possibility of some important practical applications.
In Catalytic, R N A , published as Volume
10 of the series Nucleic Acids and Molecular Biology, over 50 recognized experts
have contributed to a comprehensive survey of the current state of research. The
first three chapters are concerned with the
system that served as the historical starting point for this field of research, the selfsplicing group I introns. First there is an
excellent and instructive account of the
structure and mode of action of these ribozymes. The reader is given a sound and
understandable introduction to the subject, including considerations of substrate
recognition, different catalytic strategies,
‘ This section contains book reviews and a list of
new books received by the editor. Book reviews are
written by invitation from the editor. Suggestions
for hooks t o he reviewed and for book reviewers
are welcome Publishers should send brochures or
(better) books to the editorial office. Redaktion
Angewandte Chemie. Postfach 1011 61, D-69451
Weinheim. Germany. The editor reserves the right
of selecting which hooks will he reviewed. Uninvited books not chosen for review will not be returned.
Anxeic.. Chem. l i i r .
Ed Enxl. 1997. 36, No. 9
and a comparative analysis of mechanisms. This is followed by a discussion of
the dynamics of group I ribozymes, which
have been investigated by fluorescence
spectroscopy, and a lucid summary of
structural data and models for describing
the interactions with different substrates.
Next there come five articles on separate topics: on the interactions of aminoglycoside antibiotics with different RNAs,
on the group I1 introns, which have a wide
variety of catalytic functions, on the ribonuclease P formed from RNA and
protein subunits, on the hairpin ribozyme,
and on circular RNAs.
The largest part of the book is devoted
to the system that is at present the most
thoroughly understood : the hammerhead
ribozyme. The crystal structure of this ribozyme is discussed in detail and compared with the structure determination in
solution. Several articles are devoted to
mechanistic studies by means of chemical
modification. In addition to fundamental
studies of structure and mechanism in this
system, considerable work has been carried out on the use of such molecules for
the control of gene expression. Different
strategies for introducing ribozymes into
cells and organisms are described, as also
are approaches for using ribozymes to inhibit HIV replication. Ribozymes and antisense RNA in fungi are discussed. The
volume ends with two articles on in vitro
selection of artificial ribozymes, comparing the two different procedures used:
direct selection and selection against transition state analogs. These recent studies
are especially interesting to chemists, as
they offer the possibility of developing tailored catalysts.
The editors have succeeded in putting
together an excellent and well-integrated
work. Most of the chapters are thorough
and detailed review articles of an excellent
didactic standard, and can usefully be
read by newcomers to the field as well as
by specialists. The figures are of high
quality, some in color, and are a valuable
aid to the reader’s understanding. The
high standard of the work is also maintained in the well chosen and up-to-date
literature references. The long section on
the hammerhead ribozyme contains some
unavoidable repetition and overlapping
VCH Verlaggesell.schaf! m h H , 0-69451 Weinheim.1997
of subject matter; however, this has the
advantage that these chapters are selfcontained and can be read independently.
A work such as this, reviewing progress
in a rapidly advancing field, is inevitably a
snapshot of the situation, and in the short
time since the publication deadline some
further new and interesting facets have
appeared. The volume can be thoroughly
recommended, both as an introduction
and for a more detailed study to gain a
thorough understanding of the subject.
Every biochemistry library should have a
copy. I strongly recommend not only
bioorganic chemists but also others working in interdisciplinary areas between
chemistry and the biosciences to read this
Andres Jaschke
Institut fur Biochemie
der Freien Universitat Berlin
Crop Protection Agents from Nature.
Natural Products and Analogues. Edited by L. G. Copping. Royal Society,
London, 1996. 501 pp., hardcover
E 129.50.-ISBN 0-85404-414-0
Plant protection is essential. That cannot be denied by any serious person with
a responsible attitude towards ensuring
that agricultural products are available in
the required amounts and quality for
feeding a population of 5 billion. During
the past 50 years we have all become accustomed to the very good and reliable
supply of food that has been made possible by modern high-yielding agriculture.
However, it is now no longer generally
appreciated that the increase in efficiency,
which is quite amazing from a historical
standpoint, has largely been achieved
through the use of chemical crop protection agents. Instead, public attitudes are
now focussed not on the benefits but almost exclusively on the risks. The demand
for limiting the use of plant protection
chemicals has led to a large number of
regulatory controls, prohibitions, and restrictions on innovation. The problem of
protecting plant crops against other organisms (fungi, insects, weeds, etc.) still
remains, and therefore research on new
0570-O8331Y7!3609-/OJS$ 17.50+ SOIO
products continues despite the restrictions, while on the other hand there is a
search for effective alternatives to the conventional methods.
The balance between those processes
that destroy life and those that protect it
has become incorporated into nature as a
working principle. This is one of the areas
in which alternative principles of plant
protection are being sought, by some people in a spirit almost akin to a religious
crusade, and by others with a cool, rational purposefulness.
In this book L. G. Copping has
brought together 14 experienced specialists (or research groups) to report on this
subject, drawn from universities (28 YO),
public research institutes (32%0), and industry (22 O h from manufacturers of conventional pesticides and 16% from biotechnology businesses). Two-thirds of the
contributors are from the USA and Great
Britain. The end result is an excellent
book which analyzes the complex scientific and practical problems with a refreshing Anglo-American pragmatism, and
proposes solutions. The theme of using
the methods of nature, which is so often
presented as part of a revolutionary new
movement, is instead treated here in a factual and unpretentious way, with a wealth
of historical background, empiricism, and
appraisal of successes and failures, and
distinguishing between what is possible
and what is unattainable.
Thus, in considering ways of protecting
plants by the use of natural products, synthetic variants of these, or antagonistic organisms, the book does not aim to give
answers to the question “good or bad?”,
but instead examines whether they are
suitable or unsuitable.
In his introduction Copping presents
some interesting statistics about the importance of natural products, and about
information from nature that is relevant
to research on substances with pharmacological or plant protection activity. Of the
25 most important pharmaceutical products, about half are natural products or
variants thereof. Pyrethroids and carbamates, which are synthetic variants of lead
structures derived from nature, are very
important as insecticides. If one also includes relationships that became apparent
only after the discovery of active agents,
then even the organophosphates are seen
to have their forerunners in nature, and
the same is true of the newly developed
chloronicotinyls. Thus, it is well worth
seeking clues from nature.
The chapter by Lange and Lopez describes 32 microbial active agents that already have important applications in
plant protection or have potential in that
area. The authors also discuss the mechanisms of their activity, thus providing important information for research on new
active agents. Regrettably, however, there
are no data about levels of activity, nor
even qualitative comparisons.
The following chapter, by Yamaguchi,
is more informative in that respect, giving
details of 11 microbial active agents,
mostly Japanese discoveries, that are currently in use in Japan. The use of such
expensive but very interesting substances
is only possible because of the unusual situation in Japanese agriculture, which is
generously subsidized. This excellent
chapter would have been even more useful
if the author had included a critical discussion of the economic aspects. Nevertheless, the descriptions of the individual
active agents are packed with valuable information, including their mechanisms,
and should be read by all researchers in
the field. Unfortunately the structures are
very complex and therefore cannot be seriously considered as a starting point for
synthetic analogs.
On the other hand, all chemists interested in synthesizing variants based on lead
structures will enjoy reading the chapter
by Sauter, Ammermann, and Roehl, in
which they describe the work that led
from the natural fungicide strobiiurin to
the new synthetic variants developed for
practical use. Woven within their account
of the discovery, biological evaluation
studies, and synthetic work, the reader
will find a great wealth of information on
structure and activity. The chapter is an
instructive example for anyone involved
in research on active agents.
Duke, Abbas, Amasoga, and Tanaka
contribute a more factually orientated
chapter on 24 microbial phytotoxins, including their structures and modes of action. However, they do not give enough
information about levels of activity, activity spectra, and their potential for practical use.
This is followed by an extensive review
(by Dixon) of biologically active substances from algae including 175 structural formulas, mostly quite complicated,
and over 600 literature references. This is
very interesting so far as it goes, but contains little information relating directly to
plant protection. However, the reader is
given an excellent insight into the world of
algae and their biology, classification,
lifestyle, and metabolic products, aspects
that are of interest from a medical standpoint.
The chapter entitled “Pesticides from
Nature” consists of three short contributions of varying quality by different authors. Altogether 73 structures are given,
VCH VerlagsgesellschufimbH, 0-69451 Weinheim. 1997
mostly of well-known types (although
that of azadirachtin is incorrect). Here
again, however, the other important aspect, the biological activity (level of activity, comparisons, activity spectrum), is
hardly covered at all.
The chapter by Benner on plant protecting substances derived from higher
plants (with 26 structures) reviews practical applications of such agents, and includes some important critical comments
about the worthwhileness of evaluating
natural products with weak activity, an
important issue in all areas of natural
products research.
The three most successful lines of research starting from natural lead structures up to now have been those based on
the strobilurins (the most recent example,
still an active topic), the earlier juvenoids,
and the pyrethroids, now regarded as virtually worked out. Elliott, the doyen of
research in this area, has contributed a
50-page chapter which is a tour de force of
the high standard expected from this author. It is in effect a mini-textbook on the
optimization of active agents derived
from lead structures, with a wealth of historical background and detailed analysis
of structure-activity relationships for the
synthetic variants evaluated. Every chemistry student about to take a final degree
examination should read this beforehand.
Regrettably, this kind of science has not
yet become an essential part of all university chemistry courses.
Parr contributes a very good chapter in
which he considers whether plants have
genuine natural protection mechanisms
of their own, and summarizes current
knowledge bearing on this central question. The conclusion is that in the vast
majority of cases they do, by means of
repellent substances, elicitors, plant hormones, warning substances such as salicylic acid, and their immune systems, and
indeed one can see this just by looking out
from one’s window. The biochemical
chains of activity are explained in detail.
This makes interesting reading for the
chemist involved in research on active
agents, and raises the question of how this
knowledge can be translated into a practical form for use by the farmer.
Toxins produced by animals to catch
insects hold a special fascination for
chemists working in the area of insecticides. Blagborough and Moya discuss research based on such toxins as lead structures, and give 80 structural formulas;
unfortunately, however, they do not include the required information about the
effects of the compounds on insects. The
pharmacology of insects differs in some
respects from that of other animals, and
$ 17.501- SOj0
Angen. Chem. In[. Ed. Engl. 1997, 36, No. 9
therefore some information about the
mechanisms of activity would have been
useful for the reader. Thus, the collection
of structures given here is of little use to
the chemist working on active agents, and
does not offer lead structures for the synthetic chemist.
The main facts about one natural
product of considerable practical importance can be found in the 20-page chapter
by Adams, Liu, MacIntosh, and Starnes,
who present a very good survey of a class
of insecticides: the crystal protein toxins
derived from BuciElus thuringiensis. Their
toxicity to insects is, in molar terms,
about 300 times greater than that of
pyrethroids! The authors give a concise
and informative account of the history,
analysis, and classification of the toxins
and the different species of bacteria, their
activities, practical applications, the underlying molecular biology, and the mode
of action. The present situation with regard to their practical usefulness and potential is critically evaluated.
In an equally good chapter Leiry and
Fuxa discuss the difficulties encountered
in developing practical applications of
natural and genetically modified baculoviruses as insect pathogens. They
devote special attention to the problems
of obtaining registration to allow the use
of such methods of plant protection.
A topic that is even further removed
from plant protection based on chemicals
is the use of antagonistic microorganisms
to protect against fungal diseases. Pusey
gives a concise, critical, and readable account of the most important potential uses and the practical problems.
The use of microorganisms to combat
weeds is another strategy that is still far
from being developed to a stage suitable
for use by the farmer. Drawing on knowledge from many years of work in this area,
Greaves gives a detailed explanation of
the principles and of strategies that have
already been tried or can be envisaged,
and summarizes results from experiments
over a period of 20 years. He critically
evaluates the prospects for this speculative and risky area of research, and emphasizes the need to concentrate expensive research effort on weeds of greatest
practical importance. The closer one gets
to success with proposed solutions of
this kind, the more one is concerned
about the problem of obtaining registration for these “biological weapons” against
Angen. Clwm lnr. Ed. Engl. 1997, 36. No. 9
In the last chapter Plimmer discusses
the complications involved in getting registration for alternative methods of plant
protection. These 20 pages should be
compulsory reading for everyone who is
concerned with the legislation governing
the use of plant protection systems. Furthermore, critics of plant protection measures should read this chapter to learn
about the safety requirements that are imposed by the authorities, and must have
been satisfied by any modern plant protection agent.
To summarize, Copping’s book contains a wealth of valuable information for
chemists, biologists, agronomists, and
specialists employed by public bodies, as
well as non-scientists interested in environmental matters. At a time when some
of the expectations with regard to using
the natural world are unrealistic (as in the
background to the International Convention on Biodiversity), this book is a factual resource to help one evaluate research
aimed at learning from nature for the purpose of plant protection.
Klaus Naumann
Leverkusen (Germany)
Golf Balls, Boomerangs and Asteroids-The Impact of Missiles on
Society. By B. H. Kaye. VCH Verlagsgesellschaft, Weinheim, 1996. 41 8
pp., hardcover DM 168.00/softcover
DM 78.00.-ISBN 3-521-29332-113527-29323-X
In this book Brian Kaye has undertaken the challenging task of introducing liberal science students to a variety of physical problems, using an interesting
approach which is based on the concept of
missiles. His notion of missiles ranges
from sports tools such as golf balls and
boomerangs up to ballistic missiles and
asteroids. Finally he also treats human beings as missiles, when they are involved in
car accidents o r boxing matches. This
spans a wide range of physical problems
that are covered in the book, from thermodynamics, mechanics, astrophysics,
and optics, up to some aspects of modern
particle physics such as the detection of
solar neutrinos. Thus, the reader obtains a
broad overview of physics.
Aiming at students without a science
background, the author manages to
present this wide variety of topics in a
0 VCH Verlugs~e.~ellscli~~l
mbH, 0-69451 Weinheim, I997
down-to-earth fashion using a well-structured approach. Each section starts with a
historical introduction describing the evolution of the individual area of science and
the achievements of the scientists involved. He uses “word webs” to explain
the Latin or Greek origins of the related
terminology and to provide links to words
used in other areas of technology. This
avoids the risk of the inexperienced reader
being confused simply by the words. The
author‘s writing style and a selection of
very graphic examples (such as the physics
of baseball and tennis, and the fight between David and Goliath, which was decided by the use of a missile, namely the
stone slung by David) result in an entertaining and interesting excursion into the
world of physics. Using numerous diagrams and viewgraphs instead of equations, the author is able to explain complicated matters in a way easily accessible to
the inexperienced reader. Unfortunately,
he relies heavily on examples taken from
weapons technology, which he describes
with evident fascination.
Many questions that will interest others
as well as first-year students are answered
in this book: why d o golf balls have dimples?-how
are hailstorms produced?
Newspaper articles and accounts from
witnesses of the manifestations of physical
phenomena enliven the graphic style of his
explanations. Especially impressive (and
shocking) are reports describing the impact of meteors, and a first-hand account
of the effects of a laser beam hitting a
human eye and leading to its irreversible
The book, which is intended as the second in a triad constituting a course for
liberal science majors, is not only interesting for students who want to get a first
idea of physics. It also constitutes an ample reservoir for university teachers and
provides examples, explanations, and suggestions for pepping up introductory
physics courses. A lot of interesting ideas
and experiments can be used to raise interest in physics, in particular in audiences
that include students with different specializations. As a treatment of physics at
an introductory level, the book has its limitations for the scientific reader. it is, however, a good choice for people without a
physics background who are interested in
the historical aspects.
Stephun J. Zilker
Physikalisches Institut der Universitat
Bayreuth (Germany)
OS7o-os33i97I3609-IOI7~17.50+ S O i O
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