Paracoccidioides species complex : ecology, phylogeny, sexual reproduction, and virulence

Paracoccidioidomycosis (PCM) is a deep systemic mycosis caused by human fungal pathogens of the Paracoccidioides genus. The disease is geographically restricted to subtropical areas of Latin America (from south of Mexico to north of Argentina) with a high prevalence in Brazil, Colombia, Venezuela, and Argentina [1]. The annual incidence rate in Brazil is 10–30 infections per million inhabitants, and the mean mortality rate is 1.4 per million inhabitants per year, making this disease the highest cause of mortality among systemic mycoses [2]. PCM is endemic in rural populations and mainly affects individuals engaged in agricultural activities, who inhale aerosols containing fungal material during manipulation of the soil. Molecular evolutionary studies place the genus Paracoccidioides in the thermodimorphic fungal pathogen clade related to the family Ajellomycetaceae (Ascomycetes), which includes the Blastomyces, Histoplasma, and Emmonsia genera, and with which it shares a common ancestor, Lacazia loboi. PCM can be caused by two species Paracoccidioides brasiliensis and P. lutzii [3]. P. brasiliensis has been considered a single species since its discovery, although several studies including molecular and morphological data support the split of P. brasiliensis into two species [3,4]. P. lutzii is composed of a single monophyletic and recombining population so far found in central, southwest, and north Brazil and Ecuador [3–5]. On the other hand, P. brasiliensis contains a complex of at least four different cryptic species (S1, PS2, PS3 and PS4; Figure 1A [6]). P. brasiliensis S1 represents a monophyletic and recombining population widely distributed in South America and has been associated with the majority of cases of PCM detected up until the present time. Strains belonging to P. brasiliensis S1 have previously been recovered from armadillos, soil, and penguin feces [6]. P. brasiliensis PS2 is a paraphyletic and recombining population identified so far only in Brazil and Venezuela [6]. P. brasiliensis PS3 is comprised of a monophyletic and clonal population that has been recovered in humans and armadillos in endemic regions of Colombia [6]. P. brasiliensis PS4 was recently identified and is composed of a monophyletic population of clinical isolates from Venezuela [5,7]. Besides the typical bicorn cocked hat– and barrel-shaped conidia produced by both species, P. lutzii frequently produces elongated rod-shaped conidia, a characteristic feature that may be used for species identification [3]. Because of the difficulties of conidia production in the laboratory and slight morphological differences among species, molecular identification of Paracoccidioides species has become the most common tool of choice. Several molecular markers have already been applied in population studies of the Pararacoccidioides genus, and for multilocus sequencing typing, gp43, arf, b-tub, and hsp70 loci are the best choices for species delineation [4,6]

Improving air quality in metropolitan Mexico City : an economic valuation

Mexico City has for years experienced high levels of ozone and particulate air pollution. In 1995-99 the entire population of the Mexico City metropolitan area was exposed to annual average concentrations of fine particulate pollution (particulates with a diameter of less than 10micrometers, or PM10) exceeding 50 micrograms per cubic meter, the annual average standard in both Mexico and the United States. Two million people were exposed to annual average PM10 levels of more than 75 micrograms per cubic meter. The daily maximum one-hour ozone standard was exceeded at least 300 days a year. The Mexico Air Quality Management Team documents population-weighted exposures to ozone and PM10 between 1995 and 1999, project exposures in 2010, and computes the value of four scenarios for 2010: A 10 percent reduction in PM10 and ozone. A 20 percent reduction in PM10 and ozone. Achievement of ambient air quality standards across the metropolitan area. A 68 percent reduction in ozone and a 47 percent reduction in PM10 across the metropolitan area. The authors calculate the health benefits of reducing ozone and PM10 for each scenario using dose-response functions from the peer-reviewed literature. They value cases of morbidity and premature mortality avoided using three approaches: Cost of illness and forgone earnings only (low estimate). Cost of illness, forgone earnings, and willingness to pay for avoided morbidity (central case estimate). Cost of illness, forgone earnings, willingness to pay for avoided morbidity, and willingness to pay for avoided mortality (high estimate). The results suggest that the benefits of a 10 percent reduction in ozone and PM10 in 2010 are about $760 million (in 1999 U.S. dollars) annually in the central case. The benefits of a 20 percent reduction in ozone and PM10 are about$1.49 billion annually. In each case the benefits of reducing ozone amount to about 15 percent of the total benefits. By estimating the magnitude of the benefits from air pollution control, the authors provide motivation for examining specific policies that could achieve the air pollution reductions that they value. They also provide unit values for the benefits from reductions in ambient air pollution (for example, per microgram of PM10) that could be used as inputs into a full cost-benefit analysisof air pollution control strategies.Montreal Protocol,Public Health Promotion,Global Environment Facility,Air Quality&Clean Air,Health Monitoring&Evaluation,Montreal Protocol,Air Quality&Clean Air,Health Monitoring&Evaluation,Global Environment Facility,Transport and Environment

Comparative Genomic Analysis of Human Fungal Pathogens Causing Paracoccidioidomycosis

Paracoccidioides is a fungal pathogen and the cause of paracoccidioidomycosis, a health-threatening human systemic mycosis endemic to Latin America. Infection by Paracoccidioides, a dimorphic fungus in the order Onygenales, is coupled with a thermally regulated transition from a soil-dwelling filamentous form to a yeast-like pathogenic form. To better understand the genetic basis of growth and pathogenicity in Paracoccidioides, we sequenced the genomes of two strains of Paracoccidioides brasiliensis (Pb03 and Pb18) and one strain of Paracoccidioides lutzii (Pb01). These genomes range in size from 29.1 Mb to 32.9 Mb and encode 7,610 to 8,130 genes. To enable genetic studies, we mapped 94% of the P. brasiliensis Pb18 assembly onto five chromosomes. We characterized gene family content across Onygenales and related fungi, and within Paracoccidioides we found expansions of the fungal-specific kinase family FunK1. Additionally, the Onygenales have lost many genes involved in carbohydrate metabolism and fewer genes involved in protein metabolism, resulting in a higher ratio of proteases to carbohydrate active enzymes in the Onygenales than their relatives. To determine if gene content correlated with growth on different substrates, we screened the non-pathogenic onygenale Uncinocarpus reesii, which has orthologs for 91% of Paracoccidioides metabolic genes, for growth on 190 carbon sources. U. reesii showed growth on a limited range of carbohydrates, primarily basic plant sugars and cell wall components; this suggests that Onygenales, including dimorphic fungi, can degrade cellulosic plant material in the soil. In addition, U. reesii grew on gelatin and a wide range of dipeptides and amino acids, indicating a preference for proteinaceous growth substrates over carbohydrates, which may enable these fungi to also degrade animal biomass. These capabilities for degrading plant and animal substrates suggest a duality in lifestyle that could enable pathogenic species of Onygenales to transfer from soil to animal hosts.National Institute of Allergy and Infectious Diseases (U.S.)National Institutes of Health. Department of Health and Human Services (contract HHSN266200400001C)National Institutes of Health. Department of Health and Human Services(contract HHSN2722009000018C)Brazil. National Council for Scientific and Technological Developmen

4to. Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad. Memoria académica

Este volumen acoge la memoria académica de la Cuarta edición del Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad, CITIS 2017, desarrollado entre el 29 de noviembre y el 1 de diciembre de 2017 y organizado por la Universidad Politécnica Salesiana (UPS) en su sede de Guayaquil. El Congreso ofreció un espacio para la presentación, difusión e intercambio de importantes investigaciones nacionales e internacionales ante la comunidad universitaria que se dio cita en el encuentro. El uso de herramientas tecnológicas para la gestión de los trabajos de investigación como la plataforma Open Conference Systems y la web de presentación del Congreso http://citis.blog.ups.edu.ec/, hicieron de CITIS 2017 un verdadero referente entre los congresos que se desarrollaron en el país. La preocupación de nuestra Universidad, de presentar espacios que ayuden a generar nuevos y mejores cambios en la dimensión humana y social de nuestro entorno, hace que se persiga en cada edición del evento la presentación de trabajos con calidad creciente en cuanto a su producción científica. Quienes estuvimos al frente de la organización, dejamos plasmado en estas memorias académicas el intenso y prolífico trabajo de los días de realización del Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad al alcance de todos y todas

Biochemical characterization of Paracoccidioides brasiliensis α-1,3-glucanase agn1p, and its functionality by heterologous expression in Schizosaccharomyces pombe

This is an open-access article distributed under the terms of the Creative Commons Attribution License.α-1,3-Glucan is present as the outermost layer of the cell wall in the pathogenic yeastlike (Y) form of Paracoccidioides brasiliensis. Based on experimental evidence, this polysaccharide has been proposed as a fungal virulence factor. To degrade α-1,3-glucan and allow remodeling of the cell wall, α-1,3-glucanase is required. Therefore, the study of this enzyme, its encoding gene, and regulatory mechanisms, might be of interest to understand the morphogenesis and virulence process in this fungus. A single gene, orthologous to other fungal α-1,3-glucanase genes, was identified in the Paracoccidioides genome, and labeled AGN1. Transcriptional levels of AGN1 and AGS1 (α-1,3-glucan synthase-encoding gene) increased sharply when the pathogenic Y phase was cultured in the presence of 5% horse serum, a reported booster for cell wall α-1,3-glucan synthesis in this fungus. To study the biochemical properties of P. brasiliensis Agn1p, the enzyme was heterologously overexpressed, purified, and its activity profile determined by means of the degradation of carboxymethyl α-1,3-glucan (SCMG, chemically modified from P. brasiliensis α-1,3-glucan), used as a soluble substrate for the enzymatic reaction. Inhibition assays, thin layer chromatography and enzymatic reactions with alternative substrates (dextran, starch, chitin, laminarin and cellulose), showed that Agn1p displays an endolytic cut pattern and high specificity for SCMG. Complementation of a Schizosaccharomyces pombe agn1Δ strain with the P. brasiliensis AGN1 gene restored the wild type phenotype, indicating functionality of the gene, suggesting a possible role of Agn1p in the remodeling of P. brasiliensis Y phase cell wall. Based on amino acid sequence, P. brasiliensis Agn1p, groups within the family 71 of fungal glycoside hydrolases (GH-71), showing similar biochemical characteristics to other members of this family. Also based on amino acid sequence alignments, we propose a subdivision of fungal GH-71 into at least five groups, for which specific conserved sequences can be identified.This work was partially supported by Project ICGEB-VEN05 of the International Centre for Genetic Engineering and Biotechnology, Trieste, Italy. HV-D was recipient of a Ph.D scholarship awarded by FONACIT (Fondo Nacional de Ciencia, Tecnología e Innovación) Caracas, Venezuela. MP was recipiente of a MSc scholarship awarded by IVIC, Caracas Venezuela.Peer Reviewe

Biochemical characterization of Paracoccidioides brasiliensis α-1,3-glucanase Agn1p, and its functionality by heterologous Expression in Schizosaccharomyces pombe.

α-1,3-Glucan is present as the outermost layer of the cell wall in the pathogenic yeastlike (Y) form of Paracoccidioides brasiliensis. Based on experimental evidence, this polysaccharide has been proposed as a fungal virulence factor. To degrade α-1,3-glucan and allow remodeling of the cell wall, α-1,3-glucanase is required. Therefore, the study of this enzyme, its encoding gene, and regulatory mechanisms, might be of interest to understand the morphogenesis and virulence process in this fungus. A single gene, orthologous to other fungal α-1,3-glucanase genes, was identified in the Paracoccidioides genome, and labeled AGN1. Transcriptional levels of AGN1 and AGS1 (α-1,3-glucan synthase-encoding gene) increased sharply when the pathogenic Y phase was cultured in the presence of 5% horse serum, a reported booster for cell wall α-1,3-glucan synthesis in this fungus. To study the biochemical properties of P. brasiliensis Agn1p, the enzyme was heterologously overexpressed, purified, and its activity profile determined by means of the degradation of carboxymethyl α-1,3-glucan (SCMG, chemically modified from P. brasiliensis α-1,3-glucan), used as a soluble substrate for the enzymatic reaction. Inhibition assays, thin layer chromatography and enzymatic reactions with alternative substrates (dextran, starch, chitin, laminarin and cellulose), showed that Agn1p displays an endolytic cut pattern and high specificity for SCMG. Complementation of a Schizosaccharomyces pombe agn1Δ strain with the P. brasiliensis AGN1 gene restored the wild type phenotype, indicating functionality of the gene, suggesting a possible role of Agn1p in the remodeling of P. brasiliensis Y phase cell wall. Based on amino acid sequence, P. brasiliensis Agn1p, groups within the family 71 of fungal glycoside hydrolases (GH-71), showing similar biochemical characteristics to other members of this family. Also based on amino acid sequence alignments, we propose a subdivision of fungal GH-71 into at least five groups, for which specific conserved sequences can be identified

Geographical distribution and ecological niche modeling of the etiological agents of human sporotrichosis in Venezuela

The geographical distribution and ecological niche of the two circulating species of the Sporothrix genus in Venezuela was established. For this, 68 isolates of Sporothrix spp. from patients of different regions of the country were analyzed. A molecular taxonomy analysis was conducted using a fragment of the calmodulin gene (CAL), and ITS regions, confirming the presence of S. schenckii (62%) and S. globosa (38%). Computational models of ecological niche for each species were obtained by the maximum entropy method using the MaxEnt software, which predicted the best environmental conditions for the presence of the two species. These models predict that the main variables influencing the presence of S. schenckii were altitude and annual mean temperature, while for S. globosa, the more influent variable was the land use, with 82% of S. globosa located at urban areas vs 56% for S. schenckii. The results here presented could contribute to understand the specific environmental factors that might modulate the occurrence of Sporothrix spp. as well as its transmission. To our knowledge, our analyses show for the first time Sporothrix spp.-specific ecological niche data, a valuable tool to promote evidence-based public health policymaking within endemic areas of sporotrichosis.Instituto Venezolano de Investigaciones Científicas (IVIC, Venezuela

Sporotrichosis between 1898 and 2017: The evolution of knowledge on a changeable disease and on emerging etiological agents.

The description of cryptic species with different pathogenic potentials has changed the perspectives on sporotrichosis. Sporothrix schenckii causes a benign chronic subcutaneous mycosis, Sporothrix brasiliensis is highly virulent, and Sporothrix globosa mainly causes fixed cutaneous lesions. Furthermore, S. brasiliensis is the prevalent species related to cat-transmitted sporotrichosis. Sources of infection, transmission, and distribution patterns also differ between species, and variability differs between species because of different degrees of clonality. The present review article will cover several aspects of the biology of clinically relevant agents of sporotrichosis, including epidemiological aspects of emerging species. Genomic information of Sporothrix spp. is also discussed. The cell wall is an essential structure for cell viability, interaction with the environment, and the host immune cells and contains several macromolecules involved in virulence. Due to its importance, aspects of glycosylation and cell wall polysaccharides are reviewed. Recent genome data and bioinformatics analyses helped to identify specific enzymes of the biosynthetic glycosylation routes, with no homologs in mammalian cells, which can be putative targets for development of antifungal drugs. A diversity of molecular techniques is available for the recognition of the clinically relevant species of Sporothrix. Furthermore, antigens identified as diagnostic markers and putative vaccine candidates are described. Cell-mediated immunity plays a key role in controlling infection, but Sporothrix species differ in their interaction with the host. The adaptive branch of the immune response is essential for appropriate control of infection.Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Consejo Nacional de Ciencia y TecnologiaUniversidad de GuanajuatoUniversidad de Guanajuato (Convocatoria Institucional para Fortalecer la Excelencia Academica)Programa de Mejoramiento de ProfesoradoRed Tematica Glicociencia en Salud (CONACYT-Mexico)Tianjin Municipal Natural Science FoundationUniv Estado Rio De Janeiro, Dept Cell Biol, Lab Cellular Mycol & Prote, Sao Francisco Xavier St 524 PHLC 501D, BR-20550013 Rio De Janeiro, RJ, BrazilUniv Guanajuato, Dept Biol, Div Ciencias Nat & Exactas, Campus Guanajuato, Guanajuato, MexicoTianjin Acad Tradit Chinese Med, Dept Dermatol, Affiliated Hosp, Tianjin, Peoples R ChinaUniv Fed Sao Paulo, Cell Biol Div, Dept Microbiol Immunol & Parasitol, Sao Paulo, BrazilWesterdijk Fungal Biodivers Inst, Utrecht, NetherlandsRadboudumc CWZ, Ctr Expertise Mycol, Nijmegen, NetherlandsUniv Fed Sao Paulo, Cell Biol Div, Dept Microbiol Immunol & Parasitol, Sao Paulo, BrazilCNPq: 307169/2015-4CNCT: CB2011/166860CNCT: PDCPN2014-247109CNCT: FC 2015-02-834UG: 0087/13UG: 1025/2016CIFOREA: 89/2016PMP: UGTO-PTC-261TMNSC: 15JCYBJC49500Web of Scienc

Sequences used for alignments and phylogenetic tree construction.

*<p>Obtained in this work.</p><p>∼From <i>Paracoccidioides brasiliensis</i> sequence data bank: <a href="http://www.broadinstitute.org/annotation/genome/paracoccidioides_brasiliensis/MultiHome.html" target="_blank">http://www.broadinstitute.org/annotation/genome/paracoccidioides_brasiliensis/MultiHome.html</a>.</p