Unicellular eukaryotes, or the protists, represent a distinct life
type organization which is different from the multicellular life. The
world of these single-celled organisms is primarily comprised of
flagellated and ciliated creatures because most protists possess
flagella or cilia at certain stages of their life cycle. In the new
book, Klaus Hausmann, Renate Radek and their 15 coauthors summarize
numerous aspects of cilia/flagella structural and functional
organization and ciliate/flagellate biology. The table of contents of
this volume includes a short Preface and an attractive Introduction,
14 most informative chapters organized in 7 sections (Ultrastructure,
Cell Biology, Motility, Taxonomy and Systematics, Symbiosis,
Biodiversity, Retroand Prospective), Addendum including the curricula
vitae of contributors, scientific humor division and acknowledgements,
and a useful Index.
The Preface recounts that the book considers “an up-to-date summary
describing the state of our understanding of cilia/flagella and
ciliates/flagellates … without biochemical and genetic aspects”.
Nevertheless, modern molecular and genetic data are used extensively,
referred to broadly throughout many chapters, and are skillfully
interwoven with the general contents of the book.
In the Introductory chapter “Cilia and Flagella – Ciliates and
Flagellates”, K. Hausmann and R. Radek provide a clear and
comprehensive interpretation of the universal features of cilia and
flagella, their role in cell motility, and general characteristics of
ciliated and flagellated protists.
The chapter “Cellular Architecture, Growth, Morphogenesis,
Chemoattractants, and Loose Ends” by G.A. Antipa gives the history of
research on the fascinating cytoarchitecture and digestion of
Didinium. Further, there is an excellent account of the
chemoattraction process between Didinium and Paramecium. The chapter
also comprises the synthesis of studies on morphogenetic sequences in
ciliates, including the description of basal body formation and
morphogenesis of the thigmotactic field in Conchophthirus curtus. This
section of the book closes with an important statement that we need a
better mechanism to merge the ideas from molecular and organismic
biology which can cement and explain the evolutionary relationships
more carefully.
The chapter “Ejection, Ingestion, Digestion, and Expulsion in
Ciliates” by K. Hausmann deals with light and electron microscopical
studies of extrusomes, trichocysts and toxicysts, structures which are
involved in food uptake and segregation of ingesta, and contractile
vacuolar complex in ciliates. All those high-quality structural
studies bring us nearer to the understanding of how such important
parts of the ciliate cell operate as extrusive organelles or
contractile vacuoles. The author concludes the chapter with a profound
idea that modern structural studies are still of great necessity for
better understanding of behavior, physiology and biochemistry of
protists.
The chapter “A Song of Praise for Paramecium as a Model in Vesicle
Trafficking – A Sotto Voce Praise in Retrospect with certain
Reservation” by H. Plattner summarizes some of the results on vesicle
trafficking, docking and membrane fusion, exo-endocytosis and calcium
signaling in a Paramecium cell which have opened the door for
exploring numerous fundamental issues of general cell and molecular
biology. The stunning results obtained with the model Paramecium
clearly show that this system still has a future in the forthcoming
investigations.
The chapter “Ciliate Mating Types and Pheromones” by P. Luporini,
C. Alimenti and A. Vallesi starts with the history of our knowledge of
ciliate mating types and ends with a detailed description of various
structures, three-dimensional conformations, gene and multiple amino
acid sequences of pheromones, which play a key role in communication
between individuals of the same species of ciliates during conjugation
and autogamy.
In the chapter “Encounters with Cilia”, M.A. Sleigh presents a
careful and clearly described treatment of cilia/flagella movement in
model protozoan species. This is followed by the assessment of
implications of this knowledge for understanding ciliary metachronism
and propulsion of water and mucus in several unicellular and
multicellular organisms, and finalized by the overview of control of
ciliary activity. I have always been wondering how the universality of
the 9×2+2 pattern of fibrils in both flagella and cilia can harmonize
with their ability to perform quite different modes of dynamics and
beat patterns. This chapter gives, at least in part, the answer to
this crucial question.
The following chapter “How do Protists keep up?” by H. Machemer is
devoted to the indepth analysis of the investigations of ciliates’
mechanosensitivity, motility, gravitaxis and behavior. According to
the results obtained, gravikinesis in protists takes an intermediate
position between classical kinesis and taxis.
The chapter “Ctenophores and Termites – Systems for Motility” by
S.L. Tamm deals with the vast field of studies of structure,
development, regeneration, motility, mechanosensitivity, membrane
movements, electrical conduction and behavior in model organisms of
several so-called simple invertebrates, with special reference to the
intriguing mechanisms that coordinate the beating of fields of cilia
in ctenophores and flagella in termite flagellates.
D.H. Lynn, the author of the chapter “Kinetids, Concepts, and
Coincidence”, clearly shows how the transformative idea on structural
conservatism of the kinetid had led to establishing a new macrosystem
of ciliates which was later supported, to a certain degree, by studies
of molecular phylogenies of these protists. An account of Lynn’s
research career is neatly interspersed with instructive stories about
profitability of “small” and “big” concepts as well as about benefits
and sometimes not easy situations which may arise during the
cooperation and/or competition among different scientific groups.
The chapter “On Algal and other Protist Flagella and Cilia” by
Ø. Moestrup records an impressive history of flagella and cilia
studies from early days of light microscopy to the present days of
modern cell biology. The broad-scale comparative research on these
elaborate structures of locomotion has led the author to a hypothesis
that, in spite of the fact that the first eukaryotic flagellum arose
as a single organelle, the biflagellate condition for the ancestral
eukaryote was probably the most successful in the evolution. The
chapter concludes that, although the flagellum structure and functions
have been modified many times in different groups of unicellular
organisms, the 9×2+2 axoneme and the 9×3 basal body structures remain
strikingly conservative throughout the entire eukaryotic “tree of
life”.
Clarifying patterns of endosymbiosis is a pivotal issue in modern cell
biology of protists. In the chapter “Insights into the
Paramecium-Holospora and Paramecium-Chlorella Symbioses” M. Fujishima
and Y. Kodama present a comprehensive synthesis of the recent studies
on the re-establishment of this phenomenon between Paramecium caudatum
and symbiotic bacteria species Holospora and between P. bursaria and
its cytoplasmic endosymbiont, Chlorella variabilis. The allure of this
chapter is that it allows understanding of how a symbiont invades the
host cell, avoids digestion in the cytoplasm and grows within the host
cell, and what molecular mechanisms underlie these processes.
Another important chapter, “Prokaryotic Endosymbionts in Ciliates”,
written by H.-D. Görtz also discusses the unique structures, life and
infection cycles of intracellular microorganisms in ciliates. Special
attention is paid to the Paramecium species infected with
Holospora-like symbionts. The author correctly states that in the
endosymbiosis studies, ciliates have always been those very organisms
providing most important information on the issue during the last 130
years.
The chapter “Symbionts of Symbionts –Termite Flagellates and their
Bacterial Associations” by R. Radek and J.F.H. Strassert includes an
extensive overview of the symbiosis in protists, with major aspects of
the interactions between prokaryotic microbiota and flagellates
(parabasalids and oxymonads) in the hindgut of lower termites and wood
roach Cryptocercus.
The chapter “Smallest Protists in the Deepest Depths – Flagellates
from Abyssal Sea Floors” deals with the deep-sea protists, in
particular flagellates which were sampled, successfully cultivated and
studied by K. Hausmann and his colleagues. Their findings clearly
challenge the earlier conception of low protistan species richness on
the abyssal sea floor and substantiate a fruitful perspective of
further protistan diversity studies in the deep underwater
environments.
Lastly, J. Boenigk in the Chapter “Five Decades of Research in
Protistology – What have we learned?” takes the reader through the
history of protistological research, in particular during the last 50
years, explaining briefly but clearly the impact of this research on
our understanding of the world of flagellates and ciliates. He states
that studies of unicellular eukaryotes have been strongly influenced
by the historic developments of general biology, other associated
disciplines and innovative technologies which undoubtedly should help
the budding scientists better predict future discoveries in the
remarkable field of Protistology.
Some words should be said on the technical quality of this
edition. The book with its hard cover and attractive format is written
brightly and is easy to follow. It is well illustrated by 233 figures,
including line drawings of consistently high quality, aesthetically
beautiful light- and electron microscopic images, illustrating various
features of protistan biology. All the chapters draw together the
important relevant literature; references are conveniently organized
at the end of each chapter. It was a great pleasure for me to read
this book, and I congratulate the editors, Klaus Hausmann and Renate
Radek, as well as all other 15 contributors for creating an excellent
volume on ciliated and flagellated eukaryotic microorganisms.
I recommend this book without hesitation to all advanced students of
biology, professional scientists who work with and love protists, and
to anyone who wishes to deepen the knowledge and unfold the unique
world of these amazingly graceful and environmentally important
single-celled organisms.
Sergei O. Skarlato
Protistology 8 (3) 2014, p. 25-127