Related Experiment Video

Updated: Aug 14, 2026

Analysis of Embryonic and Larval Zebrafish Skeletal Myofibers from Dissociated Preparations
05:58

Analysis of Embryonic and Larval Zebrafish Skeletal Myofibers from Dissociated Preparations

Published on: November 13, 2013

Molecular phylogeny of microsporidians with particular reference to species that infect the muscles of fish

F Nilsen1, C Endresen, I Hordvik

  • 1Department of Fisheries and Marine Biology, University of Bergen, Bergen High Technology Centre, Norway. frank.nilsen@ifm.uib.no

The Journal of Eukaryotic Microbiology
|October 23, 1998
PubMed

Insights

Phylogenetic analysis of fish microsporidian ribosomal DNA reveals muscle-infecting species are polyphyletic. This challenges current classifications and suggests key morphological traits evolved multiple times.

Area of Science:

  • Microbiology
  • Parasitology
  • Molecular Phylogenetics

Background:

  • Microsporidia are obligate intracellular parasites with a significant impact on fish health.
  • The genus Pleistophora, characterized by muscle infection and an amorphous coat, has been a focus of classification.
  • Previous classifications relied heavily on morphological characteristics, including ultrastructure.

Purpose of the Study:

  • To investigate the phylogenetic relationships of fish-infecting microsporidians using ribosomal DNA (rDNA) sequences.
  • To re-evaluate the classification of the genus Pleistophora and related taxa.
  • To compare molecular phylogeny with classifications based on ultrastructural morphology.

Main Methods:

  • Sequencing of ribosomal DNA from eight species of fish-infecting microsporidians.
  • Inclusion of existing microsporidian rDNA sequences from diverse host taxa for comprehensive analysis.
  • Phylogenetic analysis using small subunit (SSU) rDNA sequences.

Main Results:

  • Muscle-infecting microsporidians of fish (Pleistophora spp.) form a polyphyletic group, questioning their current taxonomic status.
  • The amorphous coat, a key diagnostic feature for Pleistophora, likely has a polyphyletic origin.
  • Microsporidians infecting insects previously grouped with Pleistophora are phylogenetically distinct from fish muscle parasites.
  • Molecular phylogeny derived from SSU rDNA sequences conflicts with classifications based on ultrastructure.
  • Morphological characters such as diplokaryon and sporophorous vesicles appear to have evolved independently multiple times.

Conclusions:

  • The current classification of fish-infecting microsporidians, particularly the genus Pleistophora, requires significant revision.
  • Morphological characters used in microsporidian taxonomy are not always reliable indicators of evolutionary relationships.
  • Molecular data provides a more robust framework for understanding microsporidian diversity and evolution.

More Related Videos

Deciphering and Imaging Pathogenesis and Cording of Mycobacterium abscessus in Zebrafish Embryos10:38

Deciphering and Imaging Pathogenesis and Cording of Mycobacterium abscessus in Zebrafish Embryos

Published on: September 9, 2015

Modeling Tuberculosis in Mycobacterium marinum Infected Adult Zebrafish07:00

Modeling Tuberculosis in Mycobacterium marinum Infected Adult Zebrafish

Published on: October 8, 2018

Related Concept Videos

Modern Molecular Taxonomy01:29

Modern Molecular Taxonomy

Advancements in molecular biology have revolutionized the identification and characterization of bacteria, with multiple methods leveraging DNA sequencing for enhanced precision. As sequencing technologies improve and costs decline, these approaches are increasingly used in clinical, environmental, and evolutionary studies.Multilocus Sequence Typing (MLST) examines several housekeeping genes, essential chromosomal genes encoding cellular functions, to distinguish strains. Approximately...
Fungal Phylum Microsporidia01:28

Fungal Phylum Microsporidia

Microsporidia are a group of obligate intracellular fungi that were initially classified as protists but were later reclassified based on phylogenetic, molecular, and structural evidence linking them to the Chytridiomycota. These unicellular, non-motile organisms are highly specialized parasites that infect a wide range of animal hosts, including humans. They have evolved extensive genomic and metabolic reductions, making them highly dependent on their hosts for survival.Morphology and Genomic...
Diversity of Protists II01:27

Diversity of Protists II

Alveolates are a group of organisms recognized by the presence of alveoli, which are cytoplasmic sacs located beneath the cell membrane. While their function remains uncertain, alveoli may help regulate water balance by controlling how much water enters and leaves the cell. In dinoflagellates, these structures may serve as armor plates. There are three major types of alveolates: ciliates, which move using cilia; dinoflagellates, which use flagella for movement; and apicomplexans, which are...
Diversity of Protists IV01:27

Diversity of Protists IV

Amoebozoa represent a diverse group of terrestrial and aquatic protists that utilize lobe-shaped pseudopodia for locomotion and feeding. This characteristic differentiates them from the Rhizaria, which possess threadlike pseudopodia. The primary classifications within Amoebozoa include gymnamoebas, entamoebas, and the plasmodial and cellular slime molds. Phylogenetic evidence indicates that Amoebozoa diverged from a lineage that ultimately gave rise to fungi and animals.Gymnamoebas and...
Microbial Phylogeny01:28

Microbial Phylogeny

Understanding the evolutionary relationships among microorganisms is fundamental to microbial ecology and taxonomy. Phylogenetic trees are essential tools for inferring these relationships, relying primarily on comparative analyses of molecular sequences such as DNA, RNA, or proteins. In microbial studies, these trees typically depict the evolutionary paths of diverse bacterial and archaeal species by mapping genetic differences accumulated over time.Phylogenetic trees are composed of tips,...
Phylogenetic Species Concept in Microbiology01:22

Phylogenetic Species Concept in Microbiology

The phylogenetic species concept (PSC) is a framework used to delineate species based on evolutionary relationships, emphasizing shared ancestry and diagnosable genetic traits. Unlike morphological or biological species concepts, the PSC is particularly advantageous for microbial taxonomy, where traditional reproductive or phenotypic criteria often fall short due to the prevalence of asexual reproduction, minimal morphological differentiation, and widespread horizontal gene transfer among...