Genome sequencing and comparative genomics of the broad host-range pathogen Rhizoctonia solani AG8

Rhizoctonia solani is a soil-borne basidiomycete fungus with a necrotrophic lifestyle which is classified into fourteen reproductively incompatible anastomosis groups (AGs). One of these, AG8, is a devastating pathogen causing bare patch of cereals, brassicas and legumes. R. solani is a multinucleate heterokaryon containing significant heterozygosity within a single cell. This complexity posed significant challenges for the assembly of its genome. We present a high quality genome assembly of R. solani AG8 and a manually curated set of 13,964 genes supported by RNA-seq. The AG8 genome assembly used novel methods to produce a haploid representation of its heterokaryotic state. The whole-genomes of AG8, the rice pathogen AG1-IA and the potato pathogen AG3 were observed to be syntenic and co-linear. Genes and functions putatively relevant to pathogenicity were highlighted by comparing AG8 to known pathogenicity genes, orthology databases spanning 197 phytopathogenic taxa and AG1-IA.We also observed SNP-level “hypermutation” of CpG dinucleotides to TpG between AG8 nuclei, with similarities to repeat-induced point mutation (RIP). Interestingly, gene-coding regions were widely affected along with repetitive DNA, which has not been previously observed for RIP in mononuclear fungi of the Pezizomycotina. The rate of heterozygous SNP mutations within this single isolate of AG8 was observed to be higher than SNP mutation rates observed across populations of most fungal species compared. Comparative analyses were combined to predict biological processes relevant to AG8 and 308 proteins with effector-like characteristics, forming a valuable resource for further study of this pathosystem. Predicted effector-like proteins had elevated levels of non-synonymous point mutations relative to synonymous mutations (dN/dS), suggesting that they may be under diversifying selection pressures. In addition, the distant relationship to sequenced necrotrophs of the Ascomycota suggests the R. solani genome sequence may prove to be a useful resource in future comparative analysis of plant pathogens

Detection of sialic acids on Porphyromonas endodontalis cell surface

54173249549

A monoclonal antibody to glucosylceramide inhibits the growth of Fonsecaea pedrosoi and enhances the antifungal action of mouse macrophages.

Fungal glucosylceramides (GlcCer) are conserved lipid components in a large variety of pathogenic and non-pathogenic fungal species, but their biological functions are still unclear. Recent studies demonstrate that GlcCer are immunologically active components inducing the production of antifungal antibodies. In this work, a major GlcCer was purified and characterized from mycelial forms of Fonsecaea pedrosoi, the most frequent causative agent of chromoblastomycosis. As determined by fast atom bombardment mass spectrometry (FAB-MS) analysis, the purified molecule was identified as the conserved structure N-2'-hydroxyhexadecanoyl-1-beta-D-glucopyranosyl-9-methyl-4,8-sphingadienine. A monoclonal antibody (Mab) against this structure was used in indirect immunofluorescence with the different morphological stages of F. pedrosoi. Only the surface of young dividing cells was recognized by the antibody. Treatment of F. pedrosoi conidia with the Mab against GlcCer resulted in a clear reduction in fungal growth. In addition, the Mab also enhanced phagocytosis and killing of F. pedrosoi by murine cells. These results suggest that, in F. pedrosoi, GlcCer seem to be cell wall components targeted by antifungal antibodies that directly inhibit fungal development and also enhance macrophage function, supporting the use of monoclonal antibodies to GlcCer as potential tools in antifungal immunotherapy

Unique case report of a chromomycosis and Listeria in soft tissue and cerebellar abscesses after kidney transplantation

Abstract Background Chromomycosis is a rare mycotic infection encountered in tropical and subtropical regions. The disease presents as a slowly-evolving nodule that can become infected with bacteria. Here, we describe a unique association of abscesses caused by a chromomycosis and Listeria monocytogenes in a kidney transplant recipient, and didactically expose how the appropriate diagnosis was reached. Case presentation A 49-year old male originating from the Caribbean presented a scalp lesion which was surgically removed in his hometown where it was misdiagnosed as a sporotrichosis on histology, 3 years after he received a kidney transplant. He received no additional treatment and the scalp lesion healed. One year later, an abscess of each thigh due to both F. pedrosoi and L. monocytogenes was diagnosed in our institution. A contemporary asymptomatic cerebellar abscess was also found by systematic MRI. An association of amoxicillin and posaconazole allowed a complete cure of the patient without recurring to surgery. Histological slides from the scalp lesion were re-examined in our institution and we retrospectively concluded to a first localisation of the chromomycosis. We discuss the possible pathophysiology of this very unusual association. Conclusion In this case of disseminated listeriosis and chromomycosis, complete cure of the patients could be reached with oral anti-infectious treatment only

Clinical, epidemiological and mycological report on 65 patients from the Eastern Amazon region with chromoblastomycosis Relato clínico, epidemiológico e micológico de 65 pacientes com cromoblastomicose procedentes da Amazônia oriental

BACKGROUND: Chromoblastomycosis is a chronic fungal infection caused by fungi from the Dematiaceae family. According to several studies, Fonsecaea pedrosoi is the most common of these fungi. The infection is more common in tropical countries, with the Brazilian state of Pará having one of the largest infected populations worldwide. The disease is difficult to treat and recurrences are common. OBJECTIVES: To describe the epidemiological and mycological aspects of cases of chromoblastomycosis and its clinical forms in the state of Pará, Brazil. METHODS: Mycological exams (direct mycological examinations, culture and microculture) were performed and a clinical/epidemiological evaluation was made of 65 patients receiving care at the Dermatology Department of the Federal University of Pará between 2000 and 2007. The clinical classification proposed by Carrión in 1950 was used in this study. RESULTS: The majority of the patients were male (93.8%), agricultural workers (89.2%) of 45 to 55 years of age, and the majority of lesions (55.4%) were of the verrucous type, located principally on the lower limbs (81.5%). In the majority of the cases investigated (61.5%), the infection had been present for a long time, with a mean duration of 11 years. Direct mycological examination was performed in 86.2% of the patients (n=56). Of these, 96.4% (n=54) tested positive. Culture and microculture were performed in vitro in 47 cases of those that tested positive at direct microscopy, results showing Fonsecaea pedrosoi to be the only agent present in this sample. CONCLUSION: This study highlighted the extent to which chromoblastomycosis still affects the quality of life of the local population, principally individuals working in agriculture. This is a chronic disease for which there is no effective treatment. The importance of continuing to investigate this disease should be emphasized, as further studies may lead to new clinical or epidemiological findings.<br>FUNDAMENTOS: A cromoblastomicose é uma infecção fúngica crônica, causada por fungos da família Dematiaceae, sendo Fonsecaea pedrosoi a mais comum, segundo vários estudos. É mais frequente em países tropicais e o estado do Pará possui grande casuística mundial. A doença é de difícil tratamento e apresenta recorrência frequente. OBJETIVOS: Descrever os aspectos epidemiológicos, micológicos e formas clínicas dos casos de cromoblastomicose procedentes do estado do Pará - Brasil. MÉTODOS: Foram realizados exames micológicos (direto, cultura e microcultivo) e observação clinicoepidemiológica em 65 pacientes do Serviço de Dermatologia da Universidade Federal do Pará, atendidos no período de 2000 a 2007. Empregou-se a classificação clínica proposta por Carrión em 1950. RESULTADOS: Os pacientes eram, em sua maioria, homens (93,8%), lavradores (89,2%), faixa etária entre 45-55 anos, com predominância de lesões verruciformes (55,4%), localizadas principalmente nos membros inferiores (81,5%). A maioria dos casos pesquisados (61,5%) apresentou um longo tempo de doença, com uma média de 11 anos. O exame micológico direto foi realizado em 86,2% (n=56) dos pacientes; destes, 96,4% (n=54) apresentaram resultado positivo. Foram realizados cultura e microcultivo in vitro de 47 pacientes com exame micológico positivo e os resultados mostraram o Fonsecaea pedrosoi como único agente etiológico identificado nesta amostra. CONCLUSÃO: Este estudo mostrou o quanto a cromoblastomicose ainda compromete a qualidade de vida da população local, principalmente a de indivíduos que trabalham em lavouras, cursando com evolução crônica e sem tratamento eficaz. Observa-se a importância de dar continuidade a este estudo, o que poderá proporcionar novas contribuições clínicas ou epidemiológicas