Caister Academic Press

Acanthamoeba: Biology and Pathogenesis

"a must read for all scientists interested in medical and environmental microbiology" (Parasites and Vectors)
Publisher: Caister Academic Press
Author: Naveed Khan
University of Nottingham, UK
Pages: viii + 290
Publication date: February 2009
ISBN: 978-1-904455-43-1
Price: GB £199 or US $319Buy book
Publication date: February 2009
ISBN: 978-1-912530-98-4
Price: US $319Buy ebook

This book provides the first comprehensive review of Acanthamoeba research to be published. Everything that is known about Acanthamoeba is critically reviewed and divided into easy-to-follow sections. This book presents the current state of research on every aspect of this organism, detailing major advances in areas such as genomics, molecular and cellular biology, life cycles, geographical distribution, role in ecosystem, morphology, motility, phylogenetics, genotyping, metabolism, regulation of morphogenesis, host-parasite interactions, the molecular and immunological basis of pathogenesis, methods of transmission, epidemiology, clinical manifestation, diagnosis, treatment, new target development and drug resistance, as well as its role as a Trojan horse of the microbial world, including viral, bacterial, protozoal and fungal pathogens, and much more. There is a significant emphasis on our knowledge of Acanthamoeba infections that has grown in the molecular era. In addition, this book provides a historical perspective on Acanthamoeba research that will be of considerable interest.

This compilation will serve as an essential reference for parasitologists, microbiologists, immunologists, and physicians in the field of basic and medical microbiology, as well as an invaluable reference for new and experienced researchers who wish to understand this organism better. This book is the definitive guide to current research on this increasingly important organism.


"a comprehensive review of the literature concerning all aspects of Acanthamoeba research ... This book is certainly a 'must read' for all scientists interested in medical and environmental microbiology. It is a very convincing overview and foundation of what is already known about Acanthamoeba" from Parasites and Vectors (2009) 2: 16

"comprehensive review ... contains a wealth of information about the Acanthamoeba organism. It has good illustrations that would be helpful for both teaching and lecturing to a scientific audience." from Doodys Reviews (2009)

"a complete study of the acanthamoeba ... a useful reference for medical professionals" from SciTech Book News June 2009 p. 68

"This excellent book provides the first comprehensive review of Acanthamoeba, with particular emphasis on its biology and pathogenesis. ... This outstanding book presents the current state of research on every aspect of this organism, detailing major advances ... This excellent compilation will serve as an essential reference for parasitologists, microbiologists, immunologists, and physicians ... as well as an invaluable reference for new and experienced researchers who wish to better understand this fascinating organism. This book is the definitive guide to current research on this increasingly important organism. ... This excellent book would be also an indispensable acquisition for every institutional library ... will be in demand for many, many years." from Acta Parasitologica 2009 54(3): 288

"If you are interested in Acanthamoeba species, then this is the book to turn to. Kahn explores every aspect of this protozoan genus ... The thoroughness of the book is complemented by its logical organization with discrete sections that provide information on the organism's biology, life cycle, infectious nature and mode of action, the host immune response that it provokes and the therapeutic strategies that are available to us." from Microbiology Today (2009)

Table of contents
Section A. Biology and Phylogeny
• Introduction
A eukaryotic organism
Protists and protozoa
Discovery of pathogenic free-living amoebae
• Discovery of Acanthamoeba spp.
• Ecology
Distribution in the environment
Distribution in the man-made environment
Distribution in clinical settings
• Ecosystem
• Cell biology
Endoplasmic reticulum
Ribosomal RNA
Contractile vacuole and osmoregulation
Lysosome, peroxisome, and digestive vacuoles
Plasma membrane
Surface properties
Carbohydrates: glycogen storage and cell wall synthesis
Ionic distribution
Adenylate cyclase
Purine and pyrimidine
• Nuclear genome
• Mitochondrial genome
• Motility
• Molecular basis of motility
Intermediate filaments
Actin polymerization to form actin microfilaments
Regulators of actin polymerization
Actin-binding proteins
Inositol phospholipids-based regulation of actin microfilaments
GTP-binding proteins regulate actin microfilaments
Other key regulators
Acanthamoeba actin
Characterization of Acanthamoeba actin and its filaments
Acanthamoeba myosin
Structure of Acanthamoeba myosins
Activation of myosin-I and myosin-II
Localization of Acanthamoeba myosin
Myosins and motility
Polymerization of Acanthamoeba myosin
ATPase activity of myosin-I and myosin-II
Section B. Life cycle and Genotyping
• Life cycle
Trophozoite stage
Growth phase
G1 phase
S phase
G2 phase
Mitosis (M) phase
Cell division in asynchronous cultures
Cell division in synchronous cultures
Stationary phase
• What is the best stage in Acanthamoeba cell division to induce encystation?
• Encystation
At the morphological-level
At the organelle-level
RNA and protein synthesis
Golgi complex
Phagocytic and pinocytic activity
Cytoskeletal proteins
Other molecular changes
Cell wall synthesis
Cyst stage
• Regulators of life cycle
• What stimulates encystation?
Food deprivation
High cell density
Surface receptors (hyper- and hypo-osmolarity, extremes in pH)
Encystation-inducing factors
Chemical factors
• Feeding
• Metabolism
Acanthamoeba is a heterotroph (chemo-organotroph)
Glycolysis pathway (also called Embden- Meyerhof-Parnas pathway)
Krebs cycle (also called citric acid cycle or tricarboxylic acid cycle)
Electron transport
• Isolation of Acanthamoeba from the environmental samples
Xenic cultivation (non-nutrient agar plates seeded with Gram-negative bacteria)
"Axenic" cultivation
Chemically-defined medium
• Methods of encystation
• Storage
• Determination of the viability of trophozoites and cysts
• Speciation and genotyping
Use of 18S rRNA gene sequences (18S rDNA)
Section C. Acanthamoeba infections
• Human infections
Acanthamoeba keratitis
Binding to worn and unworn contact lenses
Biofilm formation
Corneal injury
Is Acanthamoeba keratitis limited to cornea
Why is it so painful?
Clinical diagnosis
Laboratory identification and differentiation of Acanthamoeba spp.
Culture of Acanthamoeba
Microscopic identification based on morphological characteristics
Isoenzyme analysis
Antibody-based assays
Immunofluorescence assays
Flow cytometry
Polymerase chain reaction
Matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS)
T4 genotype is the predominant cause of keratitis and granulomatous amoebic encephalitis
Host susceptibility
Species specificity
Risk factors
• Granulomatous amoebic encephalitis
Routes of entry into the central nervous system
Pathophysiology of granulomatous amoebic encephalitis
Clinical and laboratory diagnosis
Host susceptibility
Species and organ specificity
Risk factors
• Cutaneous Acanthamebiasis
Section D. Pathogenesis
Acanthamoeba keratitis
In vivo models
Ex vivo models
In vitro models
• Granulomatous amoebic encephalitis due to Acanthamoeba
In vivo models
Ex vivo models
In vitro models
• An opportunist with pathogenic potential
• Crossing the biological barriers
• Cornea
• Traversal of the blood-brain barrier
• Direct virulence factors
• Contact-dependent mechanisms
Acanthamoeba binds to extracellular matrix proteins
Adhesion to the host cells
Host intracellular signaling in response to Acanthamoeba
Phagosome formation and fusion with lysosomes
Lysosomal enzymes
Neuraminidase activity
Superoxide dismutases
Acanthamoeba activates plasminogen
• Contact-independent mechanisms
Hydrolytic enzymes
Glycosidases (also called glycoside hydrolases)
• Indirect virulence factors
Temperature tolerance, osmotolerance and growth at different pH
Phenotypic switching
Effect of cholesterol (or sterol biosynthesis) on Acanthamoeba virulence
Host factors
Section E. Immune response
• Non-specific immune system
Normal flora
Recruitment of phagocytes and their mode of killing
Phagocytic call for help (production of cytokines)
• Specific immune system
• What are the basic types of parasite immune evasion strategies
Non-induction of immune response
Anatomical seclusion
Mechanisms of survival in macrophages
Antigenic variation
Host mimicry
Evasion of complement
Evasion of antibodies
Interference with host immune signaling molecules
• Immune response in Acanthamoeba infections
Acanthamoeba keratitis and the immune response
From the contact lens to the cornea
Effect of contact lens wear for extended times on the innate immunity of the ocular surface
Antimicrobial peptides
Acquired immunity
Immunization using whole Acanthamoeba antigens
Immunization using specific Acanthamoeba antigens
Antibody levels in Acanthamoeba patients
Can cysts evade immune responses?
Macrophages In vivo
Neutrophils In vivo
Macrophages and neutrophils In vitro
Granulomatous amoebic encephalitis due to Acanthamoeba and the immune response
Evasion of cytokines
Evasion of antibodies
Evasion of complement
Evasion of macrophages
Acanthamoeba-specific antibodies and activated macrophages, in combination show amoebicidal effects
Evasion of neutrophils
Natural killer cell activity In vivo
• Effect of immune suppressive component in marijuana, cannabinoid delta-9-tetrahydrocannabinol on granulomatous amoebic encephalitis due to Acanthamoeba
Section F. Strategies against Acanthamoeba infections
• Chemotherapeutic agents and Acanthamoeba
• Membrane-acting agents
Polyhexamethylene biguanide
Chlorhexidine digluconate
Acriflavine hydrochloride
Phospholipid analogues
Polymyxin B
Polymyxin E (colistin)
Ergosterol biosynthesis
Amphotericin B
Benzimidazole and Benzotriazole
• Inhibitors of DNA synthesis and polyamine metabolism
Diamidine derivatives
Methylglyoxal bis (guanyl hydrazone) (MGBG)
Myristamidopropyl dimethylamine (MAPD)
Folate biosynthesis inhibitors
• RNA synthesis inhibitors
• Protein synthesis inhibitors
Macrolide compounds
• Tricyclic neuroleptic agents (calmodulin inhibition)
Trifluoperazine dihydrochloride and chlorpromazine dihydrochloride (phenothiazine compound)
• Artesunate
• Antimicrobial compounds from natural products
Animal-based natural products
Plant-based natural products
• Drug resistance in Acanthamoeba
• Disinfectants and Acanthamoeba
Disinfection agents
Heat disinfection
Microwave irradiation
Ultraviolet light irradiation
Gamma irradiation
• Future prospects for treatment
Antibody-based therapy
Using a carrier for drug delivery
Use of a liposome for drug delivery
Photodynamic chemotherapy against Acanthamoeba
Photo-inhibition of Acanthamoeba
Use of photosensitizer against Acanthamoeba
Section G. Acanthamoeba: Trojan horse of the microbial world
• A host for viruses
An evolutionary mystery
Do endosymbionts contribute to Acanthamoeba infections?
Poliovirus, echovirus, enterovirus, or vesicular stomatitis virus
• A host for yeast
• A host for protozoa
Acanthamoeba and bacteria interactions
Story of Acanthamoeba and Legionnaires' disease
Method for isolating Legionella pneumophila and amoebae from water samples
Endosymbiosis and pathogenicity
Acanthamoeba as a bacterial predator
Acanthamoeba as a host for bacterial pathogens (role as a reservoir or a Trojan horse or a vector)
Other bacterial pathogens and Acanthamoeba
Can bacterial pathogens survive the encystation of Acanthamoeba
Acanthamoeba as evolutionary precursor of pathogenicity in bacteria
Benefit for the host
Section H. Conclusions and Future Studies
• A model organism
• New approaches in the study of Acanthamoeba
Genome and transfection assays
Drug discovery and delivery
• Future research
Basic research
Host for microbial pathogens

How to buy this book

(EAN: 9781904455431 9781912530984 Subjects: [microbiology] [medical microbiology] [molecular microbiology] [parasitology] )