Morphology, ultrastructure, and molecular phylogeny of the ciliate Sonderia vorax with insights into the systematics of order Plagiopylida.

Background: Ciliates of the family Sonderiidae are common members of the eukaryotic communities in various anoxic environments. They host both ecto- and endosymbiotic prokaryotes (the latter associated with hydrogenosomes) and possess peculiar morpho-ultrastructural features, whose functions and homologies are not known. Their phylogenetic relationships with other ciliates are not completely resolved and the available literature, especially concerning electron microscopy and molecular studies, is quite scarce.

Coexistence of tubulins and ftsZ in different Prosthecobacter species.

Prosthecobacter, one of the few cultivable representatives of the bacterial phylum Verrucomicrobia, is of increasing interest to the scientific community due to the presence of tubulin genes in its genome and the apparent absence of the bacterial homologue FtsZ that is normally involved in prokaryotic cell division. These findings suggested the possibility of a vicarious takeover of the FtsZ function through these novel tubulins and opened new scenarios on the possible evolution of bacterial cytoskeleton and cell division. In the present manuscript, we report the characterization of ftsZ and ftsA homologues in different Prosthecobacter species that also possess tubulin genes.

Molecular systematics and ultrastructural characterization of a forgotten species: Chattonidium setense (Ciliophora, Heterotrichea).

In the present paper we redescribe the ciliate Chattonidium setense Villeneuve 1937 combining morphological observations (live, stained, scanning, and transmission electron microscope) with behavioral notes and molecular data. Ultrastructural analysis revealed remarkable similarities between Chattonidium and representative members of the class Heterotrichea in cortical structure and cytoplasmic organization. The most similar genus for these aspects appears to be Condylostoma.

Polynucleobacter bacteria in the brackish-water species Euplotes harpa (Ciliata Hypotrichia).

We have found a Polynucleobacter bacterium in the cytoplasm of Euplotes harpa, a species living in a brackish-water habitat, with a cirral pattern not corresponding to that of the freshwater Euplotes species known to harbor this type of bacteria. The symbiont has been found in three strains of the species, obtained by clonal cultures from ciliates collected in different geographic regions. The 16S rRNA gene sequence of this bacterium identifies it as a member of the beta-proteobacterial genus Polynucleobacter.

Identification of the bacterial endosymbionts of the marine ciliate Euplotes magnicirratus (Ciliophora, Hypotrichia) and proposal of 'Candidatus Devosia euplotis'.

This paper reports the identification of bacterial endosymbionts that inhabit the cytoplasm of the marine ciliated protozoon Euplotes magnicirratus. Ultrastructural and full-cycle rRNA approaches were used to reveal the identity of these bacteria. Based on analysis of 16S rRNA gene sequences, evolutionary trees were constructed; these placed the endosymbiont in the genus Devosia in the alpha-Proteobacteria.

A multidisciplinary approach to describe protists: a morphological, ultrastructural, and molecular study on Peritromus kahli Villeneuve-Brachon, 1940 (Ciliophora, Heterotrichea).

This study represents the first extended report on a species of the ciliate genus Peritromus, widespread in marine biotopes, characterized by a dorso-ventral differentiation peculiar among Heterotrichea. Morphological observations (live, stained, scanning, and transmission electron microscope) were combined with behavioral and molecular data. On the basis of the whole body of observations, the species was recognized as Peritromus kahli.

Growth medium recycling in Nannochloropsis sp. mass cultivation.

During cell division Nannochloropsis releases the thick and multilayered parent cell wall [Phycologia 35 (1996) 253]. The excretion of autoinhibitory substances in Nannochloropsis cultures has been also reported [J. Appl.

A multidisciplinary approach to describe protists: redescriptions of Novistrombidium testaceum Anigstein 1914 and Strombidium inclinatum Montagnes, Taylor, and Lynn 1990 (Ciliophora, Oligotrichia).

We combined behavioral, morphological (live, stained, scanning and transmission electron-microscope), and molecular data to redescribe two common, intertidal oligotrich ciliates, Novistrombidium testaceum and Strombidium inclinatum. Both species were collected from a rocky shore near Leghorn, Ligurian Sea. A literature review revealed four morphotypes of Novistrombidium testaceum that differ in subtle ways, including oral morphology.

Genes for the cytoskeletal protein tubulin in the bacterial genus Prosthecobacter.

Tubulins, the protein constituents of the microtubule cytoskeleton, are present in all known eukaryotes but have never been found in the Bacteria or Archaea. Here we report the presence of two tubulin-like genes [bacterial tubulin a (btuba) and bacterial tubulin b (btubb)] in bacteria of the genus Prosthecobacter (Division Verrucomicrobia). In this study, we investigated the organization and expression of these genes and conducted a comparative analysis of the bacterial and eukaryotic protein sequences, focusing on their phylogeny and 3D structures.

A molecular approach to the tangled intrageneric relationships underlying phylogeny in Euplotes (Ciliophora, Spirotrichea).

The cosmopolitan genus Euplotes is remarkable among ciliates for its species richness. To understand the still tangled taxonomy and phylogenetic relationships within the genus, small subunit rRNA sequences of 11 morphologically defined species colonizing different habitats were determined. Euplotes 18S rRNA is unique among ciliates for its anomalous length and high evolutionary rate.