RESUMO
Discus (Symphysodon spp.) are costly and prized specimens in the international ornamental fish trade. The majority of discus submitted to the Aquatic Animal Health Unit at the University of the West Indies School of Veterinary Medicine for necropsy between September 2010 and September 2015 had lesions consistent with Cryptobia iubilans infection, thus prompting this study. To determine the prevalence of the flagellated gastrointestinal protozoan C. iubilans in discus fish, 32 discus were sourced from 10 suppliers, including breeders, importers, and hobbyists across Trinidad. Fish were euthanized, and the internal organs, particularly the stomach and intestine, were observed under a light microscope for characteristic granulomatous lesions and/or live C. iubilans parasites. All wet-mount slides on which granulomas were observed were also Ziehl-Neelsen acid-fast stained to presumptively exclude the presence of Mycobacterium spp., the main differential when diagnosing C. iubilans-associated granulomatous gastritis or to determine the presence of dual infections. Further histological analyses were performed on stomach and intestinal sections, and transmission electron microscopy was used to confirm the parasite in stomach sections. The prevalence of C. iubilans infection was found to be 81.3%, and the prevalence of presumptive dual infections with Mycobacterium spp. was found to be 21.9%. To the best of our knowledge, this is the first documented study of C. iubilans infections in the wider Caribbean region.
Assuntos
Ciclídeos/parasitologia , Infecções por Euglenozoa/veterinária , Doenças dos Peixes/parasitologia , Kinetoplastida/fisiologia , Animais , Autopsia/veterinária , Região do Caribe/epidemiologia , Infecções por Euglenozoa/epidemiologia , Infecções por Euglenozoa/parasitologia , Doenças dos Peixes/epidemiologia , Kinetoplastida/ultraestrutura , Microscopia Eletrônica de Transmissão/veterinária , Prevalência , Estômago/parasitologia , Estômago/patologia , Estômago/ultraestrutura , Trinidad e Tobago/epidemiologiaRESUMO
Reconstructing species trees from multi-loci datasets is becoming a standard practice in phylogenetics. Nevertheless, access to high-throughput sequencing may be costly, especially with studies of many samples. The potential high cost makes a priori assessments desirable in order to make informed decisions about sequencing. We generated twelve transcriptomes for ten species of the Brazil nut family (Lecythidaceae), identified a set of putatively orthologous nuclear loci and evaluated, in silico, their phylogenetic utility using genome skimming data of 24 species. We designed the markers using MarkerMiner, and developed a script, GoldFinder, to efficiently sub-select the best makers for sequencing. We captured, in silico, all designed 354 nuclear loci and performed a maximum likelihood phylogenetic analysis on the concatenated sequence matrix. We also calculated individual gene trees with maximum likelihood and used them for a coalescent-based species tree inference. Both analyses resulted in almost identical topologies. However, our nuclear-loci phylogenies were strongly incongruent with a published plastome phylogeny, suggesting that plastome data alone is not sufficient for species tree estimation. Our results suggest that using hundreds of nuclear markers (i.e. 354) will significantly improve the Lecythidaceae species tree. The framework described here will be useful, generally, for developing markers for species tree inference.
Assuntos
Bertholletia/genética , Simulação por Computador , Genoma de Planta , Seleção Genética , Análise de Sequência de DNA , Marcadores Genéticos , Funções Verossimilhança , Filogenia , Transcriptoma/genéticaRESUMO
BACKGROUND: A key argument in favor of conserving biodiversity is that as yet undiscovered biodiversity will yield products of great use to humans. However, the link between undiscovered biodiversity and useful products is largely conjectural. Here we provide direct evidence from bioassays of endophytes isolated from tropical plants and bioinformatic analyses that novel biology will indeed yield novel chemistry of potential value. METHODOLOGY/PRINCIPAL FINDINGS: We isolated and cultured 135 endophytic fungi and bacteria from plants collected in Peru. nrDNAs were compared to samples deposited in GenBank to ascertain the genetic novelty of cultured specimens. Ten endophytes were found to be as much as 15-30% different than any sequence in GenBank. Phylogenetic trees, using the most similar sequences in GenBank, were constructed for each endophyte to measure phylogenetic distance. Assays were also conducted on each cultured endophyte to record bioactivity, of which 65 were found to be bioactive. CONCLUSIONS/SIGNIFICANCE: The novelty of our contribution is that we have combined bioinformatic analyses that document the diversity found in environmental samples with culturing and bioassays. These results highlight the hidden hyperdiversity of endophytic fungi and the urgent need to explore and conserve hidden microbial diversity. This study also showcases how undergraduate students can obtain data of great scientific significance.