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Bioelectrochemistry of Membranes. Principles and Practice. Edited by D. Walz J. Teissi and G

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Bioelectrochemistry of Membranes
Principles and
Practice. Edited by
D. Walz, J. Teissi,
and G. Milazzo.
Birkhuser Verlag,
Basel 2004.
240 pp., hardcover
E 118.00.—ISBN
3-7643-2166-0
The series Bioelectrochemistry: Principles and Practice, published under the
auspices of the Bioelectrochemical Society, aims to narrow the gap between
biologists and electrochemists by covering overlapping subjects in a common
language. The present volume is
devoted to biological membranes,
which is clearly a topic where the two
communities can meet, as most of electrochemistry is concerned with interfaces. In a short introduction, the editors
refer to other membrane-related issues
that have been discussed in previous volumes of the series. In this book, the electrical properties of the lipid bilayer are
highlighted, whereas protein-induced
functions are treated marginally.
The main electrical characteristics of
biological membranes are introduced in
Chapters 1 and 2, from the standpoints
of an electrochemical and a biological
approach, respectively.
In Chapter 1, Y. A. Chimadzev
defines the different membrane potentials, as well as their interplay, in an
authoritative treatment. The transmembrane potential difference is
derived from the selective permeability
of the membrane, whereas the surface
potential is determined by electrostatic
considerations of the serial capacitors
1590
of the membrane and the interfaces. A
section is then dedicated to the measurement of the different membrane potentials by electrochemical and spectroscopic methods.
In Chapter 2, P. OShea discusses the
molecular origin of the different potentials, as well as their biological effects.
The membrane dipole potential arising
from the lipid head-groups (and the
neighboring water molecules) is treated
in more detail. Most interestingly, the
author introduces some recent lines of
research, such as the imaging of the different membrane potentials on the cell
surface.
Taken together, these two chapters
establish a unified nomenclature and
formalism based on currently accepted
practice in electrochemistry. At this
stage, one might regret that a glossary
grouping the main physical entities,
with symbols and units, was not
included. The occasional redundancy
observed in the two chapters is not disturbing, although the repetition of the
derivation of the Gouy–Chapman
double layer was not necessary. I believe
that the juxtaposition of these two chapters is indeed an excellent way to deliver
the basic elements of membrane electrostatics, in a language understandable by
the two communities.
In Chapter 3, A. Blume presents a
very comprehensive description of
lipids, which goes beyond that found in
standard biochemistry textbooks. The
rich diversity of lipids is celebrated in
more than 90 pages, 60 figures, and 250
references. The different phases of
lipids in water, as well as models of biological membranes such as black lipid
membranes or liposomes, are discussed.
In a major section, the author reviews
many physical techniques used to
gather structural information on the
lipid bilayer (phase, packing, molecular
conformation, and dynamics). This
chapter and its bibliography can serve
as a valuable reference source for everyone interested in lipid studies.
In Chapter 4, T. Y. Tsong investigates the effect of an oscillatory electric
field on a membrane enzyme (Na+/K+ATPase). A few early experiments on
electrically stimulated K+ uptake by
erythrocytes are described, which
serves to introduce the concept of electroconformational coupling. Conditions
2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
for extracting energy from oscillating
or fluctuating electric fields are analyzed
in some depth, and possible biological
functions are discussed. The chapter is
interesting, but very specialized and narrowly focused on the authors work.
After the massive chapter on lipids,
one would have expected a similar
effort on proteins, which constitute the
other major membrane component. An
additional chapter on, say, ion channels
investigated by patch-clamp techniques,
would have given a more balanced view
of biological membranes.
Electroporation, treated in Chapters 5 and 6, is clearly an important subject in biology. The transient and reversible impairment of the barrier properties induced by the electric field is now
routinely used to deliver a variety of
molecules to the cell. In Chapter 5,
Y. A. Chizmadzhev, J. Teissi, and D.
Walz cover the phenomena of reversible
and irreversible electropermeabilization
of planar lipid bilayers. The local origin
of the effect is recognized from theoretical considerations and strongly backed
by the recent experimental evidence of
single-pore conductances by electrical
measurements. The description of alternative theories seems unnecessarily
lengthy, as these have already been covered in a very similar way in a previous
review by one of the authors. An attractive mechanism, whereby transient
pores undergo a transition from hydrophobic to hydrophilic, is then proposed,
which is supported by indirect experimental evidence. Chapter 6, by J. Teissi, extends the previous investigation
to biological cells, by introducing
aspects such as the non-uniformity of
the potential over a closed membrane
or the deformability of cells in an electric field. Other aspects, such as the
unknown role of membrane proteins,
can only be subjects of speculation.
This more technically orientated chapter describes how to observe and control
electropermeabilization. A thorough
analysis of several experiments that
used different techniques is presented,
with the aim of reaching a better understanding of a phenomenon that remains
elusive at the molecular level. In both
chapters, the mathematical formalism
is adequate, very clear, and consistent
with the rest of the book. However, I
feel that a recent biological or clinical
Angew. Chem. Int. Ed. 2005, 44, 1590 – 1592
Angewandte
Chemie
example would have illustrated the topic
better, especially for biochemists. In
addition, a noticeable lack of up-todate references limits the inspirational
power of these two last chapters.
In summary, I believe that this book
has great merits and can be read with
profit by both electrochemists and biologists (and also by biochemists and biophysicists). The different subjects are
treated very clearly and with sufficient
details to appeal to graduate students
and researchers. All the chapters are
written using the same terminology,
and there are frequent and adequate
cross-references
between
them.
Although this book actually brings a
common base to electrochemists and
biologists, it might be criticized as failing
to sufficiently highlight current opportunities for interdisciplinary collaboration.
If regarded as an independent work, the
book lacks a few important chapters on
membrane proteins and applications.
Some of this information can be found
in other volumes of the series, but then
the purchase is practically restricted to
scientific libraries.
Samuel Terrettaz
Institute of Physical Chemistry
EPFL, Lausanne (Switzerland)
DOI: 10.1002/anie.200485233
Transition Metal Arene pComplexes in Organic Synthesis
and Catalysis
(Series: Topics in
Organometallic
Chemistry, Vol. 7.).
Edited by E. Peter
Kndig. Springer
Verlag, Heidelberg
2004. 232 pp.,
hardcover
E 199.95.—ISBN
3-540-01604-X
This volume on the applications of arene
p-complexes in organic synthesis and
catalysis, which belongs to the series
Angew. Chem. Int. Ed. 2005, 44, 1590 – 1592
Topics in Organometallic Chemistry, is
edited by E. Peter Kndig, who has a
high reputation in the field. He is also
the author of two of the contributions.
The editor has succeeded well in the
selection of authors, who have particularly strong profiles in their respective
areas of research. Therefore, the book
offers the reader considerable promise.
After a concise introduction, E. P.
Kndig reviews the synthesis of h6
arene complexes in the first chapter. In
accordance with their importance, the
synthesis of tricarbonylchromium complexes is treated more extensively, followed by that of molybdenum complexes and cationic complexes of manganese, iron, and ruthenium. For each
of the metals, the standard procedures
for the synthesis of the complexes are
described, followed by a discussion of
their decomplexation possibilities. This
is particularly valuable, as the organic
chemist using transition metal complexes in synthesis is usually mainly
interested in the metal-free final product of the synthesis. As the chapter
also mentions the limitations of the
respective procedures, such as the possible presence of stoichiometric amounts
of Lewis acids in the formation of [(arene)FeCp]+ complexes, the chemist can
easily decide whether or not the procedure is of interest for the purpose in
hand.
In the second chapter, M. F. Semmelhack and A. Chelenov summarize
research directed to the lithiation of
(arene)tricarbonylchromium complexes
and subsequent reactions with electrophiles. The formation of aryllithium
complexes is discussed, and is followed
by their trapping by electrophiles.
Next, ortho-lithiation reactions and subsequent intramolecular substitution are
described. The issue of regioselectivity
in the deprotonation of (arene)tricarbonylchromium complexes is discussed in
more detail; the authors present the
material in a competent way, avoiding
lengthy redundancies. However, some
minor inaccuracies have slipped in. In
the section about metal–metal exchange
reactions, the authors write about the
retention of stereochemistry, whereas
they clearly mean that of configuration.
In the section about ortho metalation
followed by intramolecular substitution,
the description of the reaction of (fluowww.angewandte.org
robenzene)tricarbonylchromium with
butyllithium leading to g-butyrolactone
appears to show an unintended inversion of the absolute configuration. In
the discussion of the methylation of tricarbonyl(naphthalene)chromium using
LDA/MeI, carbon atoms C-1 and C-2
appear to have been interchanged.
The third chapter is written by the
same authors, and features nucleophilic
substitution reactions in (arene)tricarbonylchromium complexes. The two
sections of the chapter review substitution of heteroatoms and (formal) substitution of hydrogen. The first section is
dominated by haloarene tricarbonylchromium complexes. It goes beyond
the subject indicated in the title of the
section, by also discussing arene complexes with cationic cyclopentadienyliron, cyclopentadienylruthenium, tricarbonylmanganese, and cyclopentadienyl(ethyl)rhodium. A differentiation
between hetero and carbon nucleophiles
is made, and some aspects of cine and
tele substitutions are discussed. The predominance of tricarbonylchromium
complexes in this field is explained by
their facile decomplexation. This
aspect becomes more evident in the
second section, which discusses the substitution of hydrogen atoms of the aromatic ligand. Clearly, questions of regioselectivity are more important here, and
they are adequately discussed. Unfortunately, the last formula of the chapter
contains a mistake: the ligand is a derivative of biphenylene, not of benzocyclobutene.
A particularly important aspect of
the chemistry of arene complexes, the
de-aromatization of the ligands, is discussed very competently by E. P.
Kndig and A. Pape in the fourth chapter. By addition of carbon nucleophiles
followed by electrophiles—protonation
through addition of carbon electrophiles—one obtains, diastereoselectively, substituted cyclohexadienes that
are very useful for synthetic purposes
and are enantiomerically pure in many
cases. Whereas the use of reactions
starting from the corresponding molybdenum complexes is still in its infancy,
the authors review a number of publications reporting the use of cationic manganese complexes for such reactions,
thus nicely complementing the chemistry of the chromium complexes.
2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1591
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