BackgroundThe fungal genus Sporothrix includes at least four human pathogenic species. One of these species, S. brasiliensis, is the causal agent of a major ongoing zoonotic outbreak of sporotrichosis in Brazil. Elsewhere, sapronoses are caused by S. schenckii and S. globosa. The major aims on this comparative genomic study are: 1) to explore the presence of virulence factors in S. schenckii and S. brasiliensis; 2) to compare S. brasiliensis, which is cat-transmitted and infects both humans and cats with S. schenckii, mainly a human pathogen; 3) to compare these two species to other human pathogens (Onygenales) with similar thermo-dimorphic behavior and to other plant-associated Sordariomycetes.ResultsThe genomes of S. schenckii and S. brasiliensis were pyrosequenced to 17x and 20x coverage comprising a total of 32.3 Mb and 33.2 Mb, respectively. Pair-wise genome alignments revealed that the two species are highly syntenic showing 97.5% average sequence identity. Phylogenomic analysis reveals that both species diverged about 3.8-4.9 MYA suggesting a recent event of speciation. Transposable elements comprise respectively 0.34% and 0.62% of the S. schenckii and S. brasiliensis genomes and expansions of Gypsy-like elements was observed reflecting the accumulation of repetitive elements in the S. brasiliensis genome. Mitochondrial genomic comparisons showed the presence of group-I intron encoding homing endonucleases (HE’s) exclusively in S. brasiliensis. Analysis of protein family expansions and contractions in the Sporothrix lineage revealed expansion of LysM domain-containing proteins, small GTPases, PKS type1 and leucin-rich proteins. In contrast, a lack of polysaccharide lyase genes that are associated with decay of plants was observed when compared to other Sordariomycetes and dimorphic fungal pathogens, suggesting evolutionary adaptations from a plant pathogenic or saprobic to an animal pathogenic life style.ConclusionsComparative genomic data suggest a unique ecological shift in the Sporothrix lineage from plant-association to mammalian parasitism, which contributes to the understanding of how environmental interactions may shape fungal virulence. . Moreover, the striking differences found in comparison with other dimorphic fungi revealed that dimorphism in these close relatives of plant-associated Sordariomycetes is a case of convergent evolution, stressing the importance of this morphogenetic change in fungal pathogenesis.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2164-15-943) contains supplementary material, which is available to authorized users.

The yeast communities associated with the stingless bees Tetragonisca angustula, Melipona quadrifasciata and Frieseomelitta varia were studied. The bees T. angustula and F. varia showed a strong association with the yeast Starmerella meliponinorum. M. quadrifasciata more frequently carried a species related to Candida apicola, but also vectored low numbers of S. meliponinorum. Some of the yeasts isolated from adult bees were typical of species known to occur in flowers. Other yeast species found in adult bees were more typical of those found in the phylloplane. S. meliponinorum and the species in the C. apicola complex, also part of the Starmerella clade, may have a mutualistic relationship with the bees studied. Many yeasts in that group are often found in bees or substrates visited by bees, suggesting that a mutually beneficial interaction exists between them.

Sporotrichosis is a polymorphic disease caused by a complex of thermodimorphic fungi including S. brasiliensis, S. schenckii sensu stricto (s. str.), S. globosa and S. luriei. Humans and animals can acquire the disease through traumatic inoculation of propagules into the subcutaneous tissue. Despite the importance of sporotrichosis as a disease that can take epidemic proportions there are just a few studies dealing with genetic polymorphisms and genomic architecture of these pathogens. The main objective of this study was to investigate chromosomal polymorphisms and genomic organization among different isolates in the S. schenckii complex. We used pulsed field gel electrophoresis (PFGE) to separate chromosomal fragments of isolated DNA, followed by probe hybridization. Nine loci (β-tubulin, calmodulin, catalase, chitin synthase 1, Internal Transcribed Spacer, Pho85 cyclin-dependent kinase, protein kinase C Ss-2, G protein α subunit and topoisomerase II) were mapped onto chromosomal bands of Brazilian isolates of S. schenckii s. str. and S. brasiliensis. Our results revealed the presence of intra and interspecies polymorphisms in chromosome number and size. The gene hybridization analysis showed that closely related species in phylogenetic analysis had similar genetic organizations, mostly due to identification of synteny groups in chromosomal bands of similar sizes. Our results bring new insights into the genetic diversity and genome organization among pathogenic species in the Sporothrix schenckii complex.

Thirty-two strains of the novel species Starmerella meliponinorum sp. nov. were isolated from various substrates associated with three stingless bee species (tribe Meliponini) in Brazil and one in Costa Rica. The strains were found in garbage pellets (faecal material, discarded pollen or food, etc.), pollen provisions, adult bees, honey and propolis of Tetragonisca angustula, in honey from Melipona quadrifasciata and in adults of Melipona rufiventris and Trigona fulviventris. The sequence of the D1/D2 domains of the large-subunit rDNA showed that the novel species belongs to the Starmerella clade and is most closely related to Candida etchellsii, although the two differ in their sequences by 7 % base substitutions. S. meliponinorum is homothallic and assimilates few carbon sources. Nitrate is utilized as a sole nitrogen source. The type strain of S. meliponinorum is strain UFMG-01-J26.1 T (=CBS 9117 T ).

Aims:  To test indigenous Saccharomyces cerevisiae as starters to produce cachaça in large‐scale in a traditional distillery, establishing the period in which, each strain predominates in the vats, chemical composition and sensory attributes of the beverage, and to compare these data with vats prepared by spontaneous fermentation. Methods and Results:  Strains were evaluated for kinetic fermentation parameters, permanence in vats, volatile compound production, and sensory attributes for the cachaças produced. In general the vats in which starter strains were used, no difference in restriction mitochondrial DNA (mtDNA) profiles of isolates was observed. In the vats in which spontaneous fermentation occurred, different mtDNA restriction profiles were observed. Most of the non‐Saccharomyces species isolated could be regarded as contaminants of fermentation. All cachaças produced, despite being recently distilled and with differences in their chemical composition, were well accepted by the judges. Conclusions:  It was possible to detect the differences in the fermentation capacities of S. cerevisiae strains, in their relative abundances at different time periods, and in the chemical compositions and sensory attributes of the resulting beverages. Significance and Impact of the Study:  The indigenous strains utilized to prepare cachaça have shown potential to be used as starters of this traditional fermentation process.

BackgroundThe subtelomeres of many protozoa are highly enriched in genes with roles in niche adaptation. T. cruzi trypomastigotes express surface proteins from Trans-Sialidase (TS) and Dispersed Gene Family-1 (DGF-1) superfamilies which are implicated in host cell invasion. Single populations of T. cruzi may express different antigenic forms of TSs. Analysis of TS genes located at the telomeres suggests that chromosome ends could have been the sites where new TS variants were generated. The aim of this study is to characterize telomeric and subtelomeric regions of T. cruzi available in TriTrypDB and connect the sequences of telomeres to T. cruzi working draft sequence.ResultsWe first identified contigs carrying the telomeric repeat (TTAGGG). Of 49 contigs identified, 45 have telomeric repeats at one end, whereas in four contigs the repeats are located internally. All contigs display a conserved telomeric junction sequence adjacent to the hexamer repeats which represents a signature of T. cruzi chromosome ends. We found that 40 telomeric contigs are located on T. cruzi chromosome-sized scaffolds. In addition, we were able to map several telomeric ends to the chromosomal bands separated by pulsed-field gel electrophoresis.The subtelomeric sequence structure varies widely, mainly as a result of large differences in the relative abundance and organization of genes encoding surface proteins (TS and DGF-1), retrotransposon hot spot genes (RHS), retrotransposon elements, RNA-helicase and N-acetyltransferase genes. While the subtelomeric regions are enriched in pseudogenes, they also contain complete gene sequences matching both known and unknown expressed genes, indicating that these regions do not consist of nonfunctional DNA but are instead functional parts of the expressed genome. The size of the subtelomeric regions varies from 5 to 182 kb; the smaller of these regions could have been generated by a recent chromosome breakage and telomere healing event.ConclusionsThe lack of synteny in the subtelomeric regions suggests that genes located in these regions are subject to recombination, which increases their variability, even among homologous chromosomes. The presence of typical subtelomeric genes can increase the chance of homologous recombination mechanisms or microhomology-mediated end joining, which may use these regions for the pairing and recombination of free ends.

BackgroundThe surface coat of Trypanosoma cruzi is predominantly composed of glycosylphosphatidylinositol-anchored proteins, which have been extensively characterized. However, very little is known about less abundant surface proteins and their role in host-parasite interactions.Methodology/ Principal FindingsHere, we described a novel family of T. cruzi surface membrane proteins (TcSMP), which are conserved among different T. cruzi lineages and have orthologs in other Trypanosoma species. TcSMP genes are densely clustered within the genome, suggesting that they could have originated by tandem gene duplication. Several lines of evidence indicate that TcSMP is a membrane-spanning protein located at the cellular surface and is released into the extracellular milieu. TcSMP exhibited the key elements typical of surface proteins (N-terminal signal peptide or signal anchor) and a C-terminal hydrophobic sequence predicted to be a trans-membrane domain. Immunofluorescence of live parasites showed that anti-TcSMP antibodies clearly labeled the surface of all T. cruzi developmental forms. TcSMP peptides previously found in a membrane-enriched fraction were identified by proteomic analysis in membrane vesicles as well as in soluble forms in the T. cruzi secretome. TcSMP proteins were also located intracellularly likely associated with membrane-bound structures. We demonstrated that TcSMP proteins were capable of inhibiting metacyclic trypomastigote entry into host cells. TcSMP bound to mammalian cells and triggered Ca2+ signaling and lysosome exocytosis, events that are required for parasitophorous vacuole biogenesis. The effects of TcSMP were of lower magnitude compared to gp82, the major adhesion protein of metacyclic trypomastigotes, suggesting that TcSMP may play an auxiliary role in host cell invasion.Conclusion/SignificanceWe hypothesized that the productive interaction of T. cruzi with host cells that effectively results in internalization may depend on diverse adhesion molecules. In the metacyclic forms, the signaling induced by TcSMP may be additive to that triggered by the major surface molecule gp82, further increasing the host cell responses required for infection.

Pathogens have evolved mechanisms to modulate host cell functions and avoid recognition and destruction by the host damage response. For many years, researchers have focused on proteins as the main effectors used by pathogens to hijack host cell pathways, but only recently with the development of deep RNA sequencing these molecules were brought to light as key players in infectious diseases. Protozoan parasites such as those from the genera Plasmodium, Toxoplasma, Leishmania, and Trypanosoma cause life-threatening diseases and are responsible for 1000s of deaths worldwide every year. Some of these parasites replicate intracellularly when infecting mammalian hosts, whereas others can survive and replicate extracellularly in the bloodstream. Each of these parasites uses specific evasion mechanisms to avoid being killed by the host defense system. An increasing number of studies have shown that these pathogens can transfer non-coding RNA molecules to the host cells to modulate their functions. This transference usually happens via extracellular vesicles, which are small membrane vesicles secreted by the microorganism. In this mini-review we will combine published work regarding several protozoan parasites that were shown to use non-coding RNAs in inter-kingdom communication and briefly discuss future perspectives in the field.