Comparative Genomics Suggests that the Fungal Pathogen Pneumocystis Is an Obligate Parasite Scavenging Amino Acids from Its Host's Lungs

Pneumocystis jirovecii is a fungus causing severe pneumonia in immuno-compromised patients. Progress in understanding its pathogenicity and epidemiology has been hampered by the lack of a long-term in vitro culture method. Obligate parasitism of this pathogen has been suggested on the basis of various features but remains controversial. We analysed the 7.0 Mb draft genome sequence of the closely related species Pneumocystis carinii infecting rats, which is a well established experimental model of the disease. We predicted 8’085 (redundant) peptides and 14.9% of them were mapped onto the KEGG biochemical pathways. The proteome of the closely related yeast Schizosaccharomyces pombe was used as a control for the annotation procedure (4’974 genes, 14.1% mapped). About two thirds of the mapped peptides of each organism (65.7% and 73.2%, respectively) corresponded to crucial enzymes for the basal metabolism and standard cellular processes. However, the proportion of P. carinii genes relative to those of S. pombe was significantly smaller for the “amino acid metabolism” category of pathways than for all other categories taken together (40 versus 114 against 278 versus 427, P<0.002). Importantly, we identified in P. carinii only 2 enzymes specifically dedicated to the synthesis of the 20 standard amino acids. By contrast all the 54 enzymes dedicated to this synthesis reported in the KEGG atlas for S. pombe were detected upon reannotation of S. pombe proteome (2 versus 54 against 278 versus 427, P<0.0001). This finding strongly suggests that species of the genus Pneumocystis are scavenging amino acids from their host's lung environment. Consequently, they would have no form able to live independently from another organism, and these parasites would be obligate in addition to being opportunistic. These findings have implications for the management of patients susceptible to P. jirovecii infection given that the only source of infection would be other humans

A software pipeline for processing and identification of fungal ITS sequences

<p>Abstract</p> <p>Background</p> <p>Fungi from environmental samples are typically identified to species level through DNA sequencing of the nuclear ribosomal internal transcribed spacer (<it>ITS</it>) region for use in BLAST-based similarity searches in the International Nucleotide Sequence Databases. These searches are time-consuming and regularly require a significant amount of manual intervention and complementary analyses. We here present software – in the form of an identification pipeline for large sets of fungal <it>ITS </it>sequences – developed to automate the BLAST process and several additional analysis steps. The performance of the pipeline was evaluated on a dataset of 350 <it>ITS </it>sequences from fungi growing as epiphytes on building material.</p> <p>Results</p> <p>The pipeline was written in Perl and uses a local installation of NCBI-BLAST for the similarity searches of the query sequences. The variable subregion <it>ITS2 </it>of the <it>ITS </it>region is extracted from the sequences and used for additional searches of higher sensitivity. Multiple alignments of each query sequence and its closest matches are computed, and query sequences sharing at least 50% of their best matches are clustered to facilitate the evaluation of hypothetically conspecific groups. The pipeline proved to speed up the processing, as well as enhance the resolution, of the evaluation dataset considerably, and the fungi were found to belong chiefly to the <it>Ascomycota</it>, with <it>Penicillium </it>and <it>Aspergillus </it>as the two most common genera. The <it>ITS2 </it>was found to indicate a different taxonomic affiliation than did the complete <it>ITS </it>region for 10% of the query sequences, though this figure is likely to vary with the taxonomic scope of the query sequences.</p> <p>Conclusion</p> <p>The present software readily assigns large sets of fungal query sequences to their respective best matches in the international sequence databases and places them in a larger biological context. The output is highly structured to be easy to process, although it still needs to be inspected and possibly corrected for the impact of the incomplete and sometimes erroneously annotated fungal entries in these databases. The open source pipeline is available for UNIX-type platforms, and updated releases of the target database are made available biweekly. The pipeline is easily modified to operate on other molecular regions and organism groups.</p

Bak4bio framework - Brasilian army knife for bioinformatics

Orientador : Prof. Dr. Alessandro BrawermanDissertação (mestrado) - Universidade Federal do Paraná, Setor de Educação Profissional e Tecnológica, Programa de Pós-Graduação em Bioinformática. Defesa: Curitiba, 09/05/2013Inclui referênciasÁrea de concetração: BioinformáticaResumo:No desenvolvimento de software para a área de Bioinformática, pesquisadores consideram vários fatores para definir as tecnologias e metodologias utilizadas em um determinado projeto, não sendo raro encontrar soluções com finalidades iguais ou similares utilizando diferentes tecnologias. Com a proposta de fortalecer a comunidade de Bioinformática, o framework BAK4BIO - Brazilian Army Knife for Bioinformatics é um conjunto de ferramentas para a construção de aplicativos para a plataformaWeb e Mobile. É composto por uma série de subsistemas, os quais possibilitam ao usuário final buscar informações nos principais bancos de dados biológicos; iniciar e supervisionar processos de Bioinformática em ambiente computacional de alto desempenho - BAK4BIO Cluster; e gerenciar arquivos relacionados a entrada e saída de processos nas nuvens - BAK4BIO BOX. Tudo isto provendo a mobilidade necessária para seus usuários, ao permitir com que todos os processos sejam iniciados a partir de um aplicativo desenvolvido para Android - o BAK4BIO Droid. Existe também módulo BAK4BIO Server, responsável por centralizar o recebimento de requisições do módulo Droid e encaminhar para o destino correto, atuando como um proxy. Finalmente, o BAK4BIO Web, criado para interagir com as soluções do framework via Web. A carência de frameworks para o desenvolvimento de ferramentas em Bioinformática encontrada na literatura demonstra que, a existência do BAK4BIO contribui para a integração entre diferentes trabalhos científicos e o coloca em destaque por seu pioneirismo em âmbito nacional na área de mobilidade. Com destaque ao módulo BAK4BIO Droid, disponível na Google PlayStore e utilizado pela comunidade científica em vários países desde o seu lançamento. Palavras-chave: Framework; Dispositivos Móveis; Integração de sistemas; Acesso a bases biológicas; Ferramentas Biológicas. xiiiAbstract: Software development for Bioinformatics, researchers consider several factors to dene the technologies and methods used in a given project, it isn't uncommon nd solutions with similar purposes using diferent technologies. With the proposal to strengthen the Bioinformatic's community, the framework BAK4BIO - Brazilian Army Knife for Bioinformatics is a set of tools for building applications for the Web and Mobile platforms. It consists of a number of subsystems, which enable the user to retrieve information on major biological databases; initiate and supervise Bioinformatics processes in highperformance computing environment - BAK4BIO Cluster, and manage related to input and output processes in clouds - BAK4BIO BOX. All this providing the necessary mobility to users by allowing that all processes start from an application developed for Android - BAK4BIO Droid. There is also BAK4BIO Server module, responsible for centralizing the receipt of requests from the Droid module and forward to the correct destination, acting as a proxy. Finally, the Web BAK4BIO designed to interact with the framework via Web solutions The lack of frameworks for the development of Bioinformatics tools found in the literature shows that the existence of BAK4BIO contributes to the integration of dierent scientic studies and highlights in for his pioneering nationwide in the area of mobility. Highlighting the BAK4BIO Droid unit, available in Google PlayStore and used by the scientic community in several countries since its launch. Key-words: Framework, Mobile Devices, System's Integration, Access to biological bases; Biological Tools. xi