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Leonel Mendoza - One of the best experts on this subject based on the ideXlab platform.
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Rhinosporidium seeberi Nuclear Cycle Activities Using Confocal Microscopy
The Journal of parasitology, 2015Co-Authors: Darly Delfino, Leonel Mendoza, Raquel VilelaAbstract:Abstract Rhinosporidium seeberi is an uncultivated Ichthyosporean infecting animals, including humans. Recent studies suggested R. seeberi undergoes synchronized nuclear division without cytokinesis. We used confocal microscopy to investigate R. seeberi nuclear division cycles in formalin-fixed tissues stained with DAPI and phalloidin. We report that R. seeberi nuclei in juvenile and intermediary sporangia synchronously divided without cytokinesis. Intermediary sporangia display numerous 3–4 μm nuclei at different mitotic stages as well as a thick inner layer with strong affinity for phalloidin. Mature sporangia showed numerous 5–12 μm cell-walled endospores, each containing a 2–4 μm in diameter nucleus. Phalloidin did not bind to the inner layers of mature sporangia or endospores. The development of a “germinative zone” in the inner layer of mature sporangia containing hundreds of nuclei was also confirmed. This study establishes that during the R. seeberi life cycle synchronous nuclear divisions without...
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Lacazia, Lagenidium, Pythium, and Rhinosporidium
Manual of Clinical Microbiology, 2015Co-Authors: Raquel Vilela, Leonel MendozaAbstract:In the past 100 years the microbial pathogens described in this chapter have been classified either as fungal and/or para-fungal protistan pathogens. Based on their apparent epidemiological connection with water, they were at one point also placed in a new category of hydrophilic infectious agents. However, based on taxonomic and other morphological characteristics, these three anomalous species were not well understood. This frustrating situation fueled a strong controversy that has only recently been solved with the advent of molecular methodologies. Despite the recent finding that both Pythium insidiosum and Rhinosporidium seeberi are protistan pathogens, they are still studied by medical mycologists, continuing a historical tradition. More recently, the finding of an oomycete in the genus Lagenidium affecting mammalian hosts alerted the medical community to the presence of a novel pathogen phenotypically similar to the fungi and indistinguishable from the clinical and pathological features displayed by P. insidiosum during infection. Based on rDNA phylogenetic analysis, the evolutionary location of the microbial pathogens discussed in this chapter is illustrated.
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Lacazia, Pythium, and Rhinosporidium
Manual of Clinical Microbiology 10th Edition, 2011Co-Authors: Leonel Mendoza, Raquel VilelaAbstract:In the past 100 years the microbial pathogens described in this chapter have been classified as fungal and/or parafungal protistan pathogens. Lacazia loboi, Pythium insidiosum and Rhinosporidium seeberi are the most prominent features of the pathogens covered in this chapter. Clinical samples from patients suspected of having lacaziosis submitted to the laboratory comprise deep-skin scrapings and tissue biopsy samples. The samples have to be processed and evaluated for the presence of uniform yeast like cells connected by small tubules forming short chains. In contrast with the other hydrophilic pathogens covered in the chapter, P. insidiosum can be cultured on various media. The first molecular approach for the diagnosis of P. insidiosum from clinical specimens was carried out with a patient with keratitis. The hyphal elements present in the specimen were identified by sequencing part of the 18S ribosomal DNA region using the NS1 and NS2 and internal transcribed spacer (ITS) universal primers. The identification of P. insidiosum using molecular methods are described in this chapter. The first two cases of rhinosporidiosis were reported in 1900 by Guillermo Rodolfo Seeber in his M.D. thesis in Argentina. Ashworth in 1923 stated that the genus Rhinosporidium proposed by Minchin and Fanthan should be adopted and that, based on the description of Seeber and the name Coccidioides seeberia reintroduced by Belou, the binomial R. seeberi has priority.
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Molecular evidence for multiple host-specific strains in the genus Rhinosporidium.
Journal of clinical microbiology, 2005Co-Authors: Victor Silva, Cristiane N. Pereira, Libero Ajello, Leonel MendozaAbstract:Rhinosporidiosis is a cutaneous and/or subcutaneous chronic disease of human and other animals caused by Rhinosporidium seeberi (2, 16-18). This granulomatous disease is characterized by the development of polyps primarily affecting the mucous membranes of the nostrils and the ocular conjunctivae of the infected hosts. Diagnosis is essentially based on the histological detection in tissues of R. seeberi's pathognomonic endosporulating sporangia in various stages of development. Rhinosporidiosis in not a life-threatening disease, and its treatment usually is limited to the surgical removal of the polyps (1, 4, 11). For the last 100 years, the taxonomic affinities of R. seeberi remained obscure, principally because this unique pathogen cannot be cultured. Thus, most of its epidemiological and taxonomical characteristics were not well understood. In 1999, a team from the United States and Sri Lanka (10) using molecular tools found that R. seeberi was phylogenetically related to a novel group of protistan microbes at the divergence between animals and fungi. This finding was soon corroborated by others (8). These microbes are presently classified in the protistal class Mesomycetozoeae. R. seeberi shares several characteristics with the other members of this class; all are aquatic microbes with spherical structures containing endospores. Most of them are unculturable and were, at one point, classified as members of the fungal or protistan kingdoms. The studies of Herr et al. (10) and later, those of Fredericks et al. (8), using the 18S SSU rRNA gene sequences of R. seeberi, showed that these regions were almost identical among mammalian hosts with rhinosporidiosis. Based on these data and those of other investigators, Rhinosporidium was considered likely to be a monotypic genus (13). Using phylogenetic analysis, we have studied the complete internal transcribed spacer 1(ITS1), 5.8S, and ITS2 sequences of eight humans, two swans, and a dog with rhinosporidiosis and have found that there are at least three well-supported groups represented by each species used in this study. This study raises the possibility that the genus Rhinosporidium may possess multiple host-specific strains.
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Lacazia loboi and Rhinosporidium seeberi: A genomic Perspective. Rev. Iberoam Micol
2005Co-Authors: Leonel Mendoza, Raquel Vilela, Patricia S. Rosa, Andrea Faria, Fernandes BeloneAbstract:In the past five years, with the use of molecular strategies the phylogenetic affini-ties of the two more resilient pathogens studied in medical mycology, Lacazia loboi and Rhinosporidium seeberi were finally deciphered. These studies found that L. loboi was the sister taxon to Paracoccidioides brasiliensis, and R. seeberi was closely related to protistan spherical aquatic fish pathogens, located at the point were animals diverged from the fungi, in the class Mesomycetozoea. These initial studies indicated that a molecular strategy was the ideal approach to further understand these anomalous pathogens. However, the limited amount of information gathered so far from few DNA sequences, although crucial to place these organisms in the tree of life and to take a glance to their ecological pre-ferences, did not provide answers to other important traits. In the following pages we discuss a genomic perspective for both pathogens and the benefit that such information could generate to understand more about these two uncultivated pa-thogens. Lacazia loboi, Rhinosporidium seeberi, Phylogenetic affinities, Genome Lacazia loboi y Rhinosporidium seeberi: un
Padmanaban K Govindaraman - One of the best experts on this subject based on the ideXlab platform.
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disseminated subcutaneous rhinosporidiosis masquerading soft tissue tumor a rare presentation
International Journal of Research in Dermatology, 2016Co-Authors: Padmanaban K Govindaraman, N. Arumugam, Muthappa Senthilkumar, Abu A ArshadAbstract:Rhinosporidiosis is a chronic granulomatous disease caused by Rhinosporidium seeberi . It primarily affects nasal cavity. Cutaneous manifestation of the disease is rare. Here we report a case of disseminated subcutaneous rhinosporidiosis, clinically and radiologically suspected to be a soft tissue tumor, which was diagnosed by FNAC and confirmed by histopathological examination.
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Case Report Disseminated subcutaneous rhinosporidiosis masquerading soft tissue tumor: a rare presentation
2016Co-Authors: Padmanaban K Govindaraman, N. Arumugam, Muthappa Senthilkumar, Abu A. ArshadAbstract:Rhinosporidiosis is a chronic granulomatous disease caused by Rhinosporidium seeberi. It primarily affects nasal cavity. Cutaneous manifestation of the disease is rare. Here we report a case of disseminated subcutaneous rhinosporidiosis, clinically and radiologically suspected to be a soft tissue tumor, which was diagnosed by FNAC and confirmed by histopathological examination.
Victor Silva - One of the best experts on this subject based on the ideXlab platform.
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Molecular evidence for multiple host-specific strains in the genus Rhinosporidium.
Journal of clinical microbiology, 2005Co-Authors: Victor Silva, Cristiane N. Pereira, Libero Ajello, Leonel MendozaAbstract:Rhinosporidiosis is a cutaneous and/or subcutaneous chronic disease of human and other animals caused by Rhinosporidium seeberi (2, 16-18). This granulomatous disease is characterized by the development of polyps primarily affecting the mucous membranes of the nostrils and the ocular conjunctivae of the infected hosts. Diagnosis is essentially based on the histological detection in tissues of R. seeberi's pathognomonic endosporulating sporangia in various stages of development. Rhinosporidiosis in not a life-threatening disease, and its treatment usually is limited to the surgical removal of the polyps (1, 4, 11). For the last 100 years, the taxonomic affinities of R. seeberi remained obscure, principally because this unique pathogen cannot be cultured. Thus, most of its epidemiological and taxonomical characteristics were not well understood. In 1999, a team from the United States and Sri Lanka (10) using molecular tools found that R. seeberi was phylogenetically related to a novel group of protistan microbes at the divergence between animals and fungi. This finding was soon corroborated by others (8). These microbes are presently classified in the protistal class Mesomycetozoeae. R. seeberi shares several characteristics with the other members of this class; all are aquatic microbes with spherical structures containing endospores. Most of them are unculturable and were, at one point, classified as members of the fungal or protistan kingdoms. The studies of Herr et al. (10) and later, those of Fredericks et al. (8), using the 18S SSU rRNA gene sequences of R. seeberi, showed that these regions were almost identical among mammalian hosts with rhinosporidiosis. Based on these data and those of other investigators, Rhinosporidium was considered likely to be a monotypic genus (13). Using phylogenetic analysis, we have studied the complete internal transcribed spacer 1(ITS1), 5.8S, and ITS2 sequences of eight humans, two swans, and a dog with rhinosporidiosis and have found that there are at least three well-supported groups represented by each species used in this study. This study raises the possibility that the genus Rhinosporidium may possess multiple host-specific strains.
Abu A Arshad - One of the best experts on this subject based on the ideXlab platform.
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disseminated subcutaneous rhinosporidiosis masquerading soft tissue tumor a rare presentation
International Journal of Research in Dermatology, 2016Co-Authors: Padmanaban K Govindaraman, N. Arumugam, Muthappa Senthilkumar, Abu A ArshadAbstract:Rhinosporidiosis is a chronic granulomatous disease caused by Rhinosporidium seeberi . It primarily affects nasal cavity. Cutaneous manifestation of the disease is rare. Here we report a case of disseminated subcutaneous rhinosporidiosis, clinically and radiologically suspected to be a soft tissue tumor, which was diagnosed by FNAC and confirmed by histopathological examination.
Abu A. Arshad - One of the best experts on this subject based on the ideXlab platform.
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Case Report Disseminated subcutaneous rhinosporidiosis masquerading soft tissue tumor: a rare presentation
2016Co-Authors: Padmanaban K Govindaraman, N. Arumugam, Muthappa Senthilkumar, Abu A. ArshadAbstract:Rhinosporidiosis is a chronic granulomatous disease caused by Rhinosporidium seeberi. It primarily affects nasal cavity. Cutaneous manifestation of the disease is rare. Here we report a case of disseminated subcutaneous rhinosporidiosis, clinically and radiologically suspected to be a soft tissue tumor, which was diagnosed by FNAC and confirmed by histopathological examination.
