Table Of ContentBacterial Growth and Form
Bacterial Growth and Form
Second Edition
by
Arthur L. Koch
SPRINGER-SCIENCE+BUSINESS MEDIA, B.V.
A c.I.P. Catalogue record for this book is available from the Library of Congress.
ISBN 978-90-481-5844-7 ISBN 978-94-017-0827-2 (eBook)
DOI 10.1007/978-94-017-0827-2
Printed on acid-free paper
AlI Rights Reserved
© 2001 Springer Science+Business Media Dordrecht
Originally published by Kluwer Academic Publishers in 200 1
Softcover reprint ofthe hardcover 2nd edition 2001
No part of the material protected by this copyright notice may be reproduced or
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TABLE OF CONTENTS
PREFACE vii
PROLOGUE: THINKING ABOUT BACTERIA 1
CHAPTER 1. FROM THE FIRST CELL TO THE LAST UNIVERSAL 9
ANCESTOR (LUA)
CHAPTER2. CONTRASTING THE CELLULAR ABILITIES OF 37
EUKARYOTESANDPROKARYOTES
CHAPTER3. BACTERIAL GROWTH 49
CHAPTER4. SYNTHESIS OF A FUNCTIONAL BACTERIAL 103
WALL
CHAPTERS. TURGOR PRESSURE OF BACTERIAL CELLS 135
CHAPTER6. THE SURFACE STRESS THEORY: NON VITALISM 161
IN ACTION
CHAPTER 7. THE MECHANICAL ASPECTS OF CELL 191
CHAPTER 8. THE GRAM-POSITVE COCCUS: 215
Enterococcus hirae
CHAPTER 9. THE GRAM-POSITIVE ROD-SHAPED 239
ORGHANISMS: Bacillus subtilis
CHAPTER 10. THE GRAM NEGATIVE ROD; NEGATIVE ROD: 271
Escherichia coli
CHAPTER 11. APICAL GROWTH OF STREPTOMYCETES 331
AND FUNGI
CHAPTER 12. TWISTING AND ROTATION DURING THE GROWTH 353
OF GRAM-POSITIVE RODS
CHAPTER 13. THE STRUCTURAL AND PHYSIOLOGICAL ROLES 367
OF THE LAYERS OF THE GRAM-NEGATIVE
BACTERIAL ENVELOPE
CHAPTER 14. GLIDING MOTILITY, PROTONMOTIVE FORCE, 391
MOTOR, AND FLAGELLAR ROTATION
CHAPTER 15. PROKARYOTE PERSPECTIVE 409
CHAPTER 16. WARS OVER BACTERIAL WALLS 425
PREFACE
I assume that you already know a good deal of microbiology. In
this book, I frequently use the word "we" by which I mean "you and I".
Together we are going to consider bacteriology from a broader
perspective and we will think our way through the important biological
problems that are frequently just skipped over in every microbiology
course. My most important reason for writing this book is to make
accessible the relevant thinking from fields of science other than
microbiology that are important to microbiology. The book is written for
people that have already have a fascination with bacteria, but can see that
their background for understanding is far complete.
This book consists of topics that are largely omitted from
microbiology textbooks and includes some mathematics, physics,
chemistry, and evolutionary biology. It contains a good deal of my own
work, both experimental and theoretical, together with a lot of
speculation. If ten times bigger, it would be a full text book on microbial
physiology. A third of the microbial physiology is covered by the recent
textbook by White (2000). Another third is no longer treated even in
current specialized tests and is greatly underrepresented in text books.
A list of all those that contributed to the ideas developed in this
book would number more than one hundred. The short list follows: Ronald
Archibald; Dick D' Ari; Terry Beveridge; Ian Burdett; Angelika Kraft;
Marta Carparr6s; Steve Cooper; Lolita Daneo-Moore; Carol Deppe; Ron
Doyle; Paul Demchick; Don Gilbert; Jean van Heijenoort; Michael
Higgins; Joachim-Volker Holtje; Kathryn Koch; Herb Kubitschek; Harold
Labischinski; Stine Levy; Neil Mendelson; Nanne Nanninga; David
Nickens; Greg Payne; Miguel de Pedro; Tom Olijhoek; Suzanne Pinette;
Harold Pooley; Elio Schaechter; Tom Schmidt, Heinz Schwarz; Uli
Schwarz; Gerry Shockman; Elaine Sonnenfeld; Tina Romeis; Marcus
Templin; John Thwaites; Frank Trueba; David White; Steve Woeste; and
Conrad Woldringh.
PROLOGUE: THINKING ABOUT BACTERIA
1. THE STRENGTHS AND WEAKNESSES OF
PROKARYOTES
2. THE COMPETITIVE EXCLUSION PRINCIPLE
3. BACTERIA ARE THE SIMPLEST ORGANISMS THAT
GROW AND REPRODUCE IN A SELF-CONTAINED
WAY
4. THE IMPORTANCE OF BEING SMALL
5. THE VARIOUS KINDS OF CELL REGULATION
6. NOW IS THE BEST TIME TO OVERVIEW GROWTH
7. PHILOSOPHY BEHIND THE PRESENTATION OF THIS
BOOK
8.ANINTERFACEBETWEENMORPHOLOGY AND
CHEMISfRY
Key ideas
Prokaryotes are simple, but sophisticated.
Prokaryotes occupy important niches.
'Minimalist' organisms do nearly everything needed to grow.
Many problems are solved by being small.
Prokaryotes have exquisite regulatory systems, different from
those of eukaryotes.
Crucial to the biology of all life forms are osmotic pressure and
turgor pressure.
1. STRENGTHS AND WEAKNESSES OF
PROKARYOTES
The purpose of this book is to outline and defend an approach to
thinking about what bacteria are and how they do what they do. Particular
emphasis is directed to their ability to establish their shapes as they grow
and divide. In this prologue I will try to convince you that the study of
bacteria and their life strategies is important even during what is being
called the Golden Age of the Developmental and Cell biology of
2 /Bacterial Growth and Form
Eukaryotic Organisms. The failing of antibiotics in modern medicine ts
reason enough, but there are many more.
The major point is that prokaryotes (both eubacteria and
archaebacteria [archaea]) do many of the same things that eukaryotes do,
but with simpler equipment employed in extremely sophisticated ways.
This idea is interwoven with others, such as that the simpler equipment
reflects a more primitive strategy that, as illustrated in the first chapter,
can tell us a good deal about the origin of life. A concept raised
throughout the book is that prokaryotic morphogenesis relies on the deft
use of biophysical principles, while eukaryotes depend on the special
properties of their mechano-proteins. A stress-resistant wall and a
cytoskeleton are both ways to combat osmotic pressure and these two
ways may have led to the evolutionary separation and divergence of
prokaryotes and eukaryotes.
2. THE COMPETITIVE EXCLUSION PRINCIPLE
In strict ecological usage 'habitat' refers to the collection of
physical and biological components of the organism's environment which
permit it to prosper (see Ricklefs and Miller, 2000). The habitat of the
eastern blue bird, Siala sialus, is fields and not forests, for example. The
'niche' is the job situation that an organism has been adapted to fill. The
downy woodpecker, Picodes pubescens, to take another example, drills
the bark of trees looking for grubs and stores seed in cavities it has dug.
The competitive exclusion principle of ecology (Gause's principle) asserts
that two organisms cannot occupy the same habitat and niche; i.e., they
cannot coexist utilizing exactly the same set of resources. While
sometimes eukaryotes appear to be coexisting in the same niche and using
a very similar habitat, when carefully examined it is found that almost
always they are occupying different niches (see Ricklefs and Miller,
2000). On the other hand, multiple occupancy seems to be common
among prokaryotes (Milkman, 1973). Probably the latter finding means
that we do not know enough about their microbiology. Very rarely are
niches shared among eubacteria, archaebacteria, or eukaryotes. Most of
these apparent exceptions are only superficial; a little further knowledge
about the organisms is enough to indicate that they really have different
strategies for exploiting different parts of the environment. Thus all
organisms have become specialized to a very high degree, but sometimes
the strengths and strategies of one kingdom outweigh the evolutionary
fine tuning adaptations in another kingdom. For example, soil fungi and
actinomycetes coexist in the soil, and differ dramatically in much of their
life style, but find regions and circumstances within the same gram of soil
where each can excel. The combined actions of organisms of all kingdoms
are symbiotic when viewed on a large scale. Just imagine the consequences
of the sudden destruction of all organisms of only one of these kingdoms.
Microbiologists frequently point to how important bacteria are for higher
Arthur L. Koehl 3
organisms. But the loss of the eukaryotes would be catastrophic to the
prokaryotes as well. The synergisms and mutualisms between kingdoms
are expressed often even on microscopic scale.
The strengths of the eukaryotes, of course, are that they have
large cells, engage in phagocytosis, form multicellular structures with the
development of tissues, reproduce biparentally as diploids, move long
distances rapidly (animals), grow above their environment (higher plants),
and grow in an extreme range of osmotic environments (particularly
fungi). Of course not all eukaryotes do all these things. One might
construct a similar list for prokaryotes. They are small enough that
internal plumbing is not required, they can be metabolically versatile so
that one carbon source can be sufficient for all needs. They can utilize
unusual energy sources (and they may require only C0 as a carbon
2
source), they can grow in unusual (extreme) environments (high/low
temperatures, acidic/basic media, high salt environments, presence of
toxic metals, etc.), and they can sometimes overcome the severe
environment of a functioning mammalian immune system. This list
overlaps with a corresponding one for plants.
3. BACTERIA ARE THE SIMPLEST CREATURES THAT
GROW & REPRODUCE IN SELF-CONTAINED WAYS
All organisms exploit their environment; many organisms exploit
other living creatures in their environment. Viruses exploit living cells for
almost all their needs, supplying only some genetic information for the
production of new viruses. We humans as a high tech society exploit
everything, inanimate or animate. We always did, and we are getting
better at it. Here we focus on the simplest classes of organisms that have
members that pursue life almost all by themselves---these are the
'minimalist' eubacteria and archaebacteria. Such organisms require the
minimum number of elements from their environment; they can grow on
a few inorganic substances and a source of exploitable energy. Through
study of these minimalist prokaryotes we come closer to understanding
the earliest forms of life that existed between the First Cell and the Last
Universal Ancestor (sometimes called the 'progenote'). The First Cell
was neither a 'minimalist' nor a chemoautotroph, but probably today's
minimalists exhibit many of the features of the Last Universal Ancestor.
The Last Universal Ancestor is by definition the organism that gave rise
to descendants leading on one hand to the eubacteria and the other hand
to the parent of the eukaryotes and archaebacteria. We take as given that
the First Cell was dependent on abiotic resources for virtually all its needs
(substrates and energy sources); it had very few functions but was capable
of evolving new ones. Evolution progressed through a succession of
successful non-saprophytic anaerobes and in so doing produced a versatile
intermediary metabolism. As the organisms progressively depleted their
4 /Bacterial Growth and Form
environment of resources that they could utilize, then they evolved ever
better metabolic enzymes and pathways and ever better membrane
transport systems to utilize substances that were available. Many of the
metabolic characters present in today's bacteria must have evolved before
the splitting into three kingdoms (domains). Such evolution would have
depended on the availability of resources. Conversely, other special
metabolic characters of bacteria had to evolve later when certain
resources began to be generated biologically.
In the case of modern bacteria that need only a single carbon
source, the metabolic capabilities to do the necessary organic chemistry
to make the full range of building blocks require several hundred enzymes.
Yet other modern microorganisms are largely dependent on their
environment for up to 100 different small molecular weight compounds.
Both strategies represent specializations and elaborations from the
primitive early state. There is a trade-off between maintaining a pathway
of biosynthesis and maintaining an active transport mechanism. The
balance point depends on the history of the cell line. It is a minor gain to
be able to do without a number of enzymes if one then has to manufacture
the extra transport capabilities to import the end product. Both the cell
that is metabolically versatile and the cell that commandeers preformed
environmental resources present different aspects of our general theme;
and in both cases they require lots of cytoplasmic membrane for adequate
absorptive area. There is a need for a high surface-to-volume ratio. This
ratio depends on cell geometry and on the cell's being small. These
features bring us back to the consideration of how the bacteria can be so
small and efficient and still be versatile and capable of rapid growth.
4. THEIMPORTANCEOFBEINGSMALL
Prokaryotic cells are small compared to eukaryotic cells.
Although many grow as separate independent cells, there are important
interactions among some bacteria. These interactions are usually few and
not essential for the biology of most prokaryotes. Again this is a major
simplification, compared to eukaryotes which effectively are large, either
because they have large cells (some protozoa) or because they are
multicellular. Bacteria do not depend on a well controlled multicellular
structure as do fungi, plants, and animals. However, a great deal of living
bacteria are in a three dimensional structure composed of other bacteria,
eukaryotic cells, or geological structures and not in dilute aqueous
suspensions such as we study them in the laboratory.
Yet another reason to study bacteria is that they are simpler in
structure; they are small enough not to need the paraphernalia that large
eukaryotic cells do, such as, vacuoles, endoplasmic reticulum, and other
indoor plumbing. (For a detailed treatment of the diffusion problem in
bacteria see Koch , 1971, 1985c, 1990b; Koch and Wang, 1982). The
