Secreted aspartyl peptidases (Saps) are virulence attributes produced by Candida albicans that participate in multiple aspects of the fungal biology and pathogenesis. In the present paper, we have shown that amprenavir, a peptidase inhibitor used in HIV chemotherapy, inhibited Sap2 and growth of C. albicans and also promoted ultrastructural alterations. Esterase activity, sterol content, biofilm formation and the expression of surface mannose- and sialic acid-rich glycoconjugates were also reduced by amprenavir.

Most studies of the molecular evolution of Heterotrichea have been based solely on the 18S-rDNA gene, which were inconsistent with morphological classification. Because of the limitations of single locus phylogenies and the recurring problem of lack of resolution of deeper nodes found in previous studies, we present hypotheses of the evolution of internal groups of the class Heterotrichea based on multi-loci analyses (18S-rDNA, 28S-rDNA, ITS1-5.8S-ITS2 region, COI and alpha-tubulin) and morphological data. Phylogenetic trees from protein coding gene data are presented for Heterotrichea for the first time. Phylogenetic analyses included Bayesian inference, maximum likelihood, maximum parsimony methods, and optimal trees were statistically compared to alternative topologies from the literature. Additionally, the Bayesian concordance approach (BCA algorithm) was used to assess the concordance factor between topologies obtained from isolated analyses. Because different loci may evolve at different rates, resulting in different gene topologies, we also estimated a species tree for Heterotrichea using the STAR coalescence-based method. The results show that: (1) single gene trees are inconsistent regarding the position of some heterotrichean families; (2) the concatenation of all data in a total-evidence tree improved the resolution of deep nodes among the heterotrichean families and genera; (3) the coalescent-based species tree is consistent with phylogenies based on the 18S-rDNA gene and shows Spirostomidae as the stem group of Heterotrichea; (4) however, the total-evidence tree suggests that the large Heterotrichea cluster is divided into nine lineages in which Peritromidae diverges at the base of the Heterotrichea tree.

Recently, the family Midichloriaceae has been described within the bacterial order Rickettsiales. It includes a variety of bacterial endosymbionts detected in different metazoan host species belonging to Placozoa, Cnidaria, Arthropoda and Vertebrata. Representatives of Midichloriaceae are also considered possible etiological agents of certain animal diseases. Midichloriaceae have been found also in protists like ciliates and amoebae. The present work describes a new bacterial endosymbiont, “Candidatus Fokinia solitaria”, retrieved from three different strains of a novel Paramecium species isolated from a wastewater treatment plant in Rio de Janeiro (Brazil). Symbionts were characterized through the full-cycle rRNA approach: SSU rRNA gene sequencing and fluorescence in situ hybridization (FISH) with three species-specific oligonucleotide probes. In electron micrographs, the tiny rod-shaped endosymbionts (1.2 x 0.25–0.35 μm in size) were not surrounded by a symbiontophorous vacuole and were located in the peripheral host cytoplasm, stratified in the host cortex in between the trichocysts or just below them. Frequently, they occurred inside autolysosomes. Phylogenetic analyses of Midichloriaceae apparently show different evolutionary pathways within the family. Some genera, such as “Ca. Midichloria” and “Ca. Lariskella”, have been retrieved frequently and independently in different hosts and environmental surveys. On the contrary, others, such as Lyticum, “Ca. Anadelfobacter”, “Ca. Defluviella” and the presently described “Ca. Fokinia solitaria”, have been found only occasionally and associated to specific host species. These last are the only representatives in their own branches thus far. Present data do not allow to infer whether these genera, which we named “stand-alone lineages”, are an indication of poorly sampled organisms, thus underrepresented in GenBank, or represent fast evolving, highly adapted evolutionary lineages.

ABSTrACT. Since molecular phylogenies of stichotrich ciliates started to be published, some remarkable contradictions to morphology-based classifications have been reported, such as the Convergent Evolution of Urostylids and Uroleptids (CEUU) hyphothesis, the Halteria paradox, the polyphyly of Oxytricha and of Stichotrichia. We hypothesized the internal phylogeny of 18S-rDNA from 53 morphological species of stichotrichs and their relationships with Hypotrichia and Oligotrichia using parsimony and neighbor-joining methods, including new data from Pseudouroleptus caudatus and Strongylidium pseudocrassum. Competing phylogenetic scenarios were compared using statistical tests, and the results suggest the reconsideration of both CEUU and the position of Halteria among flexible-body oxytrichids. The polyphyly of Oxytricha was not rejected and the monophyly of Stichotrichia was accepted based on parsimony analysis if Pseudoamphisiella is considered an external (discocephalid related) taxon.

Species determination is crucial in biodiversity research. In tintinnids, identification is based almost exclusively on the lorica, despite its frequent intraspecific variability and interspecific similarity. We suggest updated procedures for identification and, depending on the aim of the study, further steps to obtain morphological, molecular, and ecological data. Our goal is to help improving the collection of information (e.g. species re-/descriptions and DNA barcodes) that is essential for generating a natural tintinnid classification and a reliable reference for environmental surveys. These suggestions are broadly useful for protistologists because they exemplify data integration, quality/effort compromise, and the need for scientific collaborations.ACCURATE species identification is critical to understand protist biodiversity in all its dimensions (taxonomic, genetic, and functional). It is also the only means to track species distributions and abundances, especially in the context of potential shifts due to climate change. Recent developments in sequencing technologies have led to the discovery of novel lineages, life styles, and physiological traits, and are more and more integrated in