Chitin in the symbiotic protist Nephromyces

Abstract

The endosymbiotic marine protist Nephromyces was first classified as a chytridiomycete by Giard in 1888, yet its taxonomic affinities with chytridiomycetes, as well as with other groups traditionally considered fungi, remain in doubt. To supplement the morphological data on which taxonomic inferences have been based, we assayed Nephromyces for chitin, using three methods: chromatographic assays of acid hydrolysates of alkali-resistant cell residues; infrared spectral analysis; and observations of N-acetylglucosamine-specific lectin-binding properties of the surfaces of living cells. All three assays indicate the presence of chitin in Nephromyces. The possible phylogenetic implications of this finding are discussed.

Nephromyces, a beneficial apicomplexan symbiont in marine animals

“…Though Nephromyces does resemble fungi in its chitinous walls, hyphal-like trophic stages, and the absence of chloroplasts, none of these characteristics is unique to fungi (6,12). Furthermore, several traits of Nephromyces, including tubular mitochondrial cristae and a posteriorly biflagellate cell stage (6,12,13), are atypical for fungi. Finally, the life cycle of Nephromyces does not resemble closely that of any fungal or protistan taxa (11).…”

2 Genomics to Study Basal Lineage Fungal Biology: Phylogenomics Suggests a Common Origin

“…Ochromonas, Chrysophyta-Chromalveolata); Thalassiosira (Heterokontophyta-Chromalveolata) and Euplotes (Ciliata-Chromalveolata) (Ward et al 1985;Saffo and Fultz 1986;Arroyo-Begovich and Crabez-Trejo 1982;Campos-Góngora et al 2004;Herth et al 1977;Brunner et al 2009;Greco et al 1990, respectively).…”