Folia Parasitologica, vol. 52 (2005), issue 1/2

The First United Workshop on Microsporidia from Invertebrate and Vertebrate Hosts

Louis M. Weiss

Folia Parasitologica 52[1/2] 1-7 (2005) | 10.14411/fp.2005.001

The phylum Microsporidia is a large group of parasitic unicellular eukaryotes that infect a wide range of invertebrate and vertebrate taxa. These organisms are significant human and veterinary pathogens with impacts on medicine, agriculture and aquaculture. Scientists working on these pathogens represent diverse disciplines that have had limited opportunities for detailed interactions. A NATO Advanced Research Workshop 'Emergent Pathogens in the 21st Century: First United Workshop on Microsporidia from Invertebrate and Vertebrate Hosts' was held July 12-15, 2004 at the Institute of Parasitology of the Academy of Sciences of the Czech Republic to bring...

Comparative genomics of microsporidia

Patrick J. Keeling, Naomi M. Fast, Joyce S. Law, Bryony A.P. Williams, Claudio H. Slamovits

Folia Parasitologica 52[1/2] 8-14 (2005) | 10.14411/fp.2005.002

Microsporidia have been known for some time to possess among the smallest genomes of any eukaryote. There is now a completely sequenced microsporidian genome, as well as several other large-scale sequencing efforts, so the nature of these genomes is becoming apparent. This paper reviews some of the characteristics of microsporidian genomes in general, and some of the recent discoveries made through comparative genomic analyses. In general, microsporidian genomes are both reduced and compacted. Reduction takes place through gene loss, which is understandable in obligate intracellular parasites that rely on their host for many metabolites. Compaction...

Post-genomics of microsporidia, with emphasis on a model of minimal eukaryotic proteome: a review

Catherine Texier, Damien Brosson, Hicham El Alaoui, Guy Méténier, Christian P. Vivarès

Folia Parasitologica 52[1/2] 15-22 (2005) | 10.14411/fp.2005.003

The genome sequence of the microsporidian parasite Encephalitozoon cuniculi Levaditi, Nicolau et Schoen, 1923 contains about 2,000 genes that are representative of a non-redundant potential proteome composed of 1,909 protein chains. The purpose of this review is to relate some advances in the characterisation of this proteome through bioinformatics and experimental approaches. The reduced diversity of the set of E. cuniculi proteins is perceptible in all the compilations of predicted domains, orthologs, families and superfamilies, available in several public databases. The phyletic patterns of orthologs for seven eukaryotic organisms...

Evolutionary strategies and adaptations for survival between mosquito-parasitic microsporidia and their intermediate copepod hosts: a comparative examination of Amblyospora connecticus and Hyalinocysta chapmani (Microsporidia: Amblyosporidae)

Theodore G. Andreadis

Folia Parasitologica 52[1/2] 23-35 (2005) | 10.14411/fp.2005.004

The epizootiology, transmission dynamics, and survival strategies employed by two mosquito-parasitic microsporidia that utilize copepods as intermediate hosts are examined in relation to the biological attributes of their hosts and the environments in which they inhabit. Amblyospora connecticus Andreadis, 1988, a parasite of Ochlerotatus cantator (Coquillett) and Acanthocyclops vernalis (Fischer) is found in an unstable salt marsh environment that is subject to periodic flooding and drying. Both hosts have distinct non-overlapping generations. A. connecticus exhibits a well-defined seasonal transmission cycle that relies...

How do microsporidia invade cells?

Caspar Franzen

Folia Parasitologica 52[1/2] 36-40 (2005) | 10.14411/fp.2005.005

Microsporidia are obligate intracellular eukaryotic parasites that utilize a unique mechanism to infect host cells. One of the main characteristics of all microsporidia is that they produce spores containing an extrusion apparatus that consists of a coiled polar tube ending in an anchoring disc at the apical part of the spore. With appropriate conditions inside a suitable host, the polar tube is discharged through the thin anterior end of the spore, thereby penetrating a new host cell for inoculating the infective sporoplasm into the new host cell. This method of invading new host cells is one of the most sophisticated infection mechanisms in biology...

Review of microsporidia-mosquito relationships: from the simple to the complex

James J. Becnel, Susan E. White, Alexandra M. Shapiro

Folia Parasitologica 52[1/2] 41-50 (2005) | 10.14411/fp.2005.006

Microsporidia in mosquitoes can be divided into two categories based on their life cycles and host-parasite relationships. Some species of microsporidia exhibit simple life cycles with one spore type responsible for oral (horizontal) transmission. They affect only one generation of the mosquito and are not usually host or tissue specific. Brachiola algerae (Vavra et Undeen, 1970) and Vavraia culicis (Weiser, 1947) are examples of species isolated from mosquitoes with relatively straightforward life cycles (one spore type) and simple host-parasite relationships. B. algerae and a close relative of V. culicis have also been...

A review of the development of two types of human skeletal muscle infections from microsporidia associated with pathology in invertebrates and cold-blooded vertebrates

Ann Cali, Louis M. Weiss, Peter M. Takvorian

Folia Parasitologica 52[1/2] 51-61 (2005) | 10.14411/fp.2005.007

Traditionally, the Microsporidia were primarily studied in insects and fish. There were only a few human cases of microsporidiosis reported until the advent of AIDS, when the number of human microsporidian infections dramatically increased and the importance of these new pathogens to medicine became evident. Over a dozen different kinds of microsporidia infecting humans have been reported. While some of these infections were identified in new genera (Enterocytozoon, Vittaforma), there were also infections identified from established genera such as Pleistophora and Encephalitozoon. The genus Pleistophora, originally...

I. Maudlin, P.H. Holmes, M.A. Miles (Eds.): The Trypanosomiases.

Jiří Lom

Folia Parasitologica 52[1/2] 62 (2005) | 10.14411/fp.2005.008

CABI Publishing, Wallingford, Oxfordshire, UK, 2004. ISBN 0-85199-475-X, hardback, 614 pp. Price £ 99.50, $ 185.00.

Review of the sequential development of Loma salmonae (Microsporidia) based on experimental infections of rainbow trout (Oncorhynchus mykiss) and Chinook salmon (O. tshawytscha)

Michael L. Kent, David J. Speare

Folia Parasitologica 52[1/2] 63-68 (2005) | 10.14411/fp.2005.009

Loma salmonae (Putz, Hoffman et Dunbar, 1965) is a common gill parasite of salmonids, and essentially all species in the genus Oncorhynchus are susceptible. Infections occur in both fresh and salt water. Loma salmonae is directly transmissible by ingestion of spores or infected tissue. The parasite infects the wall of blood vessels of various organs, but the gill is the primary site of infection. Initial infection occurs in the intestine, and xenomas are easily detected in the gills by standard histology at 4-6 wk post-exposure. A few presporogonic stages of the parasite are found in the heart endothelium prior to xenoma formation...

Microsporidian xenomas in fish seen in wider perspective

Jiří Lom, Iva Dyková

Folia Parasitologica 52[1/2] 69-81 (2005) | 10.14411/fp.2005.010

The history of understanding xenoparasitic complexes or xenomas provoked in the host cell by various protists and especially by microsporidia is outlined. Microsporidia have been known to produce xenomas in oligochaetes (e.g., genera Bacillidium, Burkea, Hrabyeia, Jirovecia, species of the collective group Microsporidium), crustaceans (e.g., Abelspora, Mrazekia), insects (e.g., Polydispyrenia, Thelohania) and poikilothermic vertebrates, mostly fish (Alloglugea, Amazonspora, Glugea, Ichthyosporidium, Loma, Microfilum, Microgemma, Neonosemoides,...

Public health importance of Brachiola algerae (Microsporidia) - an emerging pathogen of humans

Govinda S. Visvesvara, Hercules Moura, Gordon J. Leitch, David A. Schwartz, Lihua X. Xiao

Folia Parasitologica 52[1/2] 83-94 (2005) | 10.14411/fp.2005.011

Brachiola algerae (Vavra et Undeen, 1970), a parasite of Anopheles mosquitoes, has also been isolated from a human cornea, a cutaneous nodule and deep muscle tissue. All three human isolates of B. algerae are morphologically, serologically, and genetically similar to the mosquito-derived isolates including the original isolate of Vavra and Undeen. All of these isolates grew well in mammalian cell cultures at 37°C and produced spores. Transmission electron microscopy revealed that all developmental stages including meronts, sporoblasts and spores were diplokaryotic and developed in direct contact with the host cell cytoplasm, a...

Microgemma vivaresi (Microsporidia: Tetramicridae): host reaction to xenomas induced in sea scorpions, Taurulus bubalis (Osteichthyes: Cottidae)

Elizabeth U. Canning, Alan Curry

Folia Parasitologica 52[1/2] 95-102 (2005) | 10.14411/fp.2005.012

Xenomas caused by Microgemma vivaresi Canning, Feist, Longshaw, Okamura, Anderson, Tsuey Tse et Curry, 2005 were found in liver and skeletal muscle of sea scorpions, Taurulus bubalis (Euphrasen). All muscle xenomas examined were in an advanced stage of destruction. In developing xenomas found in liver, parasites were restricted to the centre of the cell, separated from a parasite-free zone by a nuclear network formed by branching of the host cell nucleus. Although xenomas were able to reach a size of several hundred microns, the surface remained a simple plasma membrane. Host reactions took the form of penetration by phagocytes and isolation...

Multinucleate host cells induced by Vittaforma corneae (Microsporidia)

Gordon J. Leitch, Andrew P. Shaw, Margaret Colden-Stanfield, Mary Scanlon, Govinda S. Visvesvara

Folia Parasitologica 52[1/2] 103-110 (2005) | 10.14411/fp.2005.013

The microsporidium Vittaforma corneae (Shadduck, Meccoli, Davis et Font, 1990) develops within the target cell cytoplasm. In the present study, green monkey kidney (E6) cells infected at 30°C, 35°C or 37°C with V. corneae developed enlarged multinucleate structures of up to 200 µm in any horizontal dimension made up either of a single cell or of multiple fused cells. A number of epithelial cell types (SW-480, HT-29, Caco-2 and HCT-8) were infected with V. corneae but did not induce the same highly organized structures, suggesting that for the structure to develop, the host cell must be capable of continued mitosis, and not...

Role of the posterior vacuole in Spraguea lophii (Microsporidia) spore hatching

Ann M. Findley, Earl H. Weidner, Kevin R. Carman, Zhimin Xu, J. Samuel Godbar

Folia Parasitologica 52[1/2] 111-117 (2005) | 10.14411/fp.2005.014

Microsporidia constitute a large group of obligate intracellular protozoan parasites that inject themselves into host cells via the extrusion apparatus of the infective spore stage. Although the injection process is poorly understood, its energy source is thought to reside in the posterior vacuole that swells significantly during spore firing. Here we report the presence and localisation of the key peroxisomal enzymes catalase and acyl-CoA oxidase (ACOX) within the posterior vacuole of Spraguea lophii (Doflein, 1898) spores. Western blot analyses show that these enzymes discharge out of the spore and end up in the medium external to the extruded...

The early events of Brachiola algerae (Microsporidia) infection: spore germination, sporoplasm structure, and development within host cells

Peter M. Takvorian, Louis M. Weiss, Ann Cali

Folia Parasitologica 52[1/2] 118-129 (2005) | 10.14411/fp.2005.015

Brachiola algerae (Vavra et Undeen, 1970) Lowman, Takvorian et Cali, 2000, originally isolated from a mosquito, has been maintained in rabbit kidney cells at 29°C in our laboratory. This culture system has made it possible to study detailed aspects of its development, including spore activation, polar tube extrusion, and the transfer of the infective sporoplasm. Employing techniques to ultrastructurally process and observe parasite activity in situ without disturbance of the cultures has provided details of the early developmental activities of B. algerae during timed intervals ranging from 5 min to 48 h. Activated and non-activated spores...

Editorial note

Vladimír Bukva

Folia Parasitologica 52[1/2] 130 (2005) | 10.14411/fp.2005.016

Molecular phylogeny of the Microsporidia: ecological, ultrastructural and taxonomic considerations

Charles R. Vossbrinck, Bettina A. Debrunner-Vossbrinck

Folia Parasitologica 52[1/2] 131-142 (2005) | 10.14411/fp.2005.017

The Microsporidia are a group of obligate intracellular parasites, now thought to be derived fungi. Presented here is a comparative small subunit rDNA (ssrDNA) analysis of 125 species of Microsporidia (sequences obtained from GenBank). This analysis shows that groups or clades are formed based largely on habitat and host. This result is supported by comparative molecular analyses of the past decade, and indicates that structural and ultrastructural characters are unreliable for distinguishing among higher-level microsporidian taxa. Our findings indicate the presence of five major clades of Microsporidia which group according to habitat. We present...

Molecular versus morphological approach to microsporidian classification

J. I. Ronny Larsson

Folia Parasitologica 52[1/2] 143-144 (2005) | 10.14411/fp.2005.018

Chromosomal composition of the genome in the monomorphic diplokaryotic microsporidium Paranosema grylli: analysis by two-dimensional pulsed-field gel electrophoresis

Elena Nassonova, Emmanuel Cornillot, Guy Méténier, Nina Agafonova, Boris Kudryavtsev, Sergei Skarlato, Christian P. Vivarès

Folia Parasitologica 52[1/2] 145-157 (2005) | 10.14411/fp.2005.019

The molecular karyotype of Paranosema grylli Sokolova, Seleznev, Dolgikh et Issi, 1994, a monomorphic diplokaryotic microsporidium, comprises numerous bright and faint bands of nonstoichiometric staining intensity. Restriction analysis of chromosomal DNAs by "karyotype and restriction display" 2-D PFGE has demonstrated that the complexity of molecular karyotype of P. grylli is related to the pronounced length polymorphism of homologous chromosomes. The background of this phenomenon is discussed in the context of ploidy state, reproductive strategy and population structure in this microsporidium. We propose that the remarkable size variation...

Humoral intestinal immunity against Encephalitozoon cuniculi (Microsporidia) infection in mice

Bohumil Sak, Oleg Ditrich

Folia Parasitologica 52[1/2] 158-162 (2005) | 10.14411/fp.2005.020

Three strains of mice, BALB/c, IL-12 knock-out (KO) and INF-γ knock-out, were chosen as an experimental model for the study of intestinal immunity induction against Encephalitozoon cuniculi Levaditi, Nicolau et Schoen, 1923 infection. Mice were infected perorally with 107 spores and re-infected with the same dose 70 days after the first infection. The anti-E. cuniculi IgA, IgG and IgM responses in sera and extracts of stool samples were determined by ELISA. Results have shown specific antibody production in the sera and intestinal secretions of all three strains of mice induced orally by E. cuniculi spores. BALB/c...

Microsporidia in aquatic microcrustacea: the copepod microsporidium Marssoniella elegans Lemmermann, 1900 revisited

Jiří Vávra, Miroslav Hyliš, Miroslav Oborník, Charles R. Vossbrinck

Folia Parasitologica 52[1/2] 163-172 (2005) | 10.14411/fp.2005.021

Marssoniella elegans Lemmermann, 1900, a parasite of ovarial tissues of the copepod Cyclops vicinus Uljanin, 1875, was studied as a representative of aquatic-clade microsporidia which form "heteroinfectious spores" (spores not infective to the original host as opposed to "homoinfectious spores" which are infective for the original host) and which thus should require an alternate host. Several structural characters of this microsporidian are similar to those of copepod morphs of microsporidia infecting mosquitoes. However, small subunit ribosomal DNA phylogeny indicates that caddis flies (Insecta, Trichoptera) might be the alternate hosts...

Antimicrosporidial activity of (fluoro)quinolones in vitro and in vivo

Elizabeth S. Didier, Lisa Bowers, Mary E. Stovall, Dorothy Kuebler, Derek Mittleider, Paul J. Brindley, Peter J. Didier

Folia Parasitologica 52[1/2] 173-181 (2005) | 10.14411/fp.2005.022

Microsporidia are a cause of emerging and opportunistic infections in humans and animals. Although two drugs are currently being used to treat microsporidiosis, concerns exist that albendazole is only selective for inhibiting some species of microsporidia that infect mammals, and fumagillin appears to have been found to be toxic. During a limited sequence survey of the Vittaforma corneae (syn. Nosema corneum Shadduck, Meccoli, Davis et Font, 1990) genome, a partial gene encoding for the ParC topoisomerase IV subunit was identified. The purpose of this set of studies was to determine if fluoroquinolones, which target topoisomerase IV,...

Investigations into microsporidian methionine aminopeptidase type 2: a therapeutic target for microsporidiosis

Hong Zhang, Huan Huang, Ann Cali, Peter M. Takvorian, Xiaochuan Feng, Ghou Zhou, Louis M. Weiss

Folia Parasitologica 52[1/2] 182-192 (2005) | 10.14411/fp.2005.023

The Microsporidia have been reported to cause a wide range of clinical diseases particularly in patients that are immunosuppressed. They can infect virtually any organ system and cases of gastrointestinal infection, encephalitis, ocular infection, sinusitis, myositis and disseminated infection are well described in the literature. While benzimidazoles such as albendazole are active against many species of Microsporidia, these drugs do not have significant activity against Enterocytozoon bieneusi. Fumagillin, ovalicin and their analogues have been demonstrated to have antimicrosporidial activity in vitro and in animal models of microsporidiosis....

\"Polar vesicles\" of microsporidia are mitochondrial remnants (\"mitosomes\")?

Jiří Vávra

Folia Parasitologica 52[1/2] 193-195 (2005) | 10.14411/fp.2005.024

Conventional transmission electron microscopy was used to localise double-membrane vesicles probably representing mitochondrial remnants ("mitosomes") in four species of microsporidia. Very few such vesicles were found dispersed throughout cytoplasm with no relationship to other cell organelles. Several double-membrane vesicles per ultrathin section, however, occurred regularly close to the nuclear spindle plaque. These vesicles are identical with the "polar vesicles" typically associated with the microsporidian spindle plaque and known since 1971. The reason for mitosome accumulation near the spindle plaque is unknown. Possibly the spindle plaques...

F. Moravec: Metazoan Parasites of Salmonid Fishes of Europe.

Vladimíra Hanzelová, Marta Špakulová

Folia Parasitologica 52[1/2] 196 (2005) | 10.14411/fp.2005.025

Academia, Prague, 2004. ISBN 80-200-1189-7, hardback, 510 pp. Price not given.