Fatal Pulmonary and Cerebellar Zygomycosis due to Rhizomucor pusillus in a Ringed Seal (Pusa hispida).

A 4-year-old captive ringed seal (Pusa hispida) was treated with subcutaneous antibacterial injections for pus exuding wounds in the skin and associated blubber following a bite attack. Three months after the incident, the animal presented nystagmus and died the following day. At necropsy, there was a 25 × 18 × 25 mm well-delineated, opaque nodular mass in the lung, besides the skin ulcers and localized areas of discoloration in the blubber correlating with the bite wound and injection sites. Histopathology of the pulmonary mass demonstrated severe eosinophilic inflammatory infiltration among numerous intralesional fungal hyphae. The hyphae were irregularly branched, broad and aseptate, consistent of zygomycosis. Magnetic resonance imaging was conducted on the head, which was initially frozen intact, revealing diffuse areas of hyperintensity in the cerebellum. Restricted histopathologic examination of the cerebellum showed severe granulomatous inflammation well spread within the neuroparenchyma, associated with abundant intralesional fungal hyphae similar to those appreciated in the pulmonary mass. Molecular analyses of the fungi in the pulmonary and cerebellar tissue identified the etiologic agent in both sites as Rhizomucor pusillus. The likely route of infection is through inhalation of R. pusillus spores or fragmented hyphae from the environment that developed into an initial pulmonary infection, becoming the source of hematogenous dissemination to the cerebellum. The skin and blubber lesions likely contributed to immunosuppression. Zygomycosis is uncommon in pinnipeds, and the present report emphasizes the importance of considering zygomycete dissemination even when the primary focus is highly confined.

Characterization and gene cloning of l-xylulose reductase involved in l-arabinose catabolism from the pentose-fermenting fungus Rhizomucor pusillus.

l-Xylulose reductase (LXR) catalyzes the reduction of l-xylulose to xylitol in the fungal l-arabinose catabolic pathway. LXR (RpLXR) was purified from the pentose-fermenting zygomycetous fungus Rhizomucor pusillus NBRC 4578. The native RpLXR is a homotetramer composed of 29 kDa subunits and preferred NADPH as a coenzyme. The Km values were 8.71 mM for l-xylulose and 3.89 mM for dihydroxyacetone. The lxr3 (Rplxr3) gene encoding RpLXR consists of 792 bp and encodes a putative 263 amino acid protein (Mr = 28,341). The amino acid sequence of RpLXR showed high similarity to 3-oxoacyl-(acyl-carrier-protein) reductase. The Rplxr3 gene was expressed in Escherichia coli and the recombinant RpLXR exhibited properties similar to those of native RpLXR. Transcription of the Rplxr3 gene in R. pusillus NBRC 4578 was induced in the presence of l-arabinose and inhibited in the presence of d-glucose, d-xylose, and d-mannitol, indicating that RpLXR is involved in the l-arabinose catabolic pathway.

Genome sequence and transcriptome analyses of the thermophilic zygomycete fungus Rhizomucor miehei.

BACKGROUND: The zygomycete fungi like Rhizomucor miehei have been extensively exploited for the production of various enzymes. As a thermophilic fungus, R. miehei is capable of growing at temperatures that approach the upper limits for all eukaryotes. To date, over hundreds of fungal genomes are publicly available. However, Zygomycetes have been rarely investigated both genetically and genomically. RESULTS: Here, we report the genome of R. miehei CAU432 to explore the thermostable enzymatic repertoire of this fungus. The assembled genome size is 27.6-million-base (Mb) with 10,345 predicted protein-coding genes. Even being thermophilic, the G + C contents of fungal whole genome (43.8%) and coding genes (47.4%) are less than 50%. Phylogenetically, R. miehei is more closerly related to Phycomyces blakesleeanus than to Mucor circinelloides and Rhizopus oryzae. The genome of R. miehei harbors a large number of genes encoding secreted proteases, which is consistent with the characteristics of R. miehei being a rich producer of proteases. The transcriptome profile of R. miehei showed that the genes responsible for degrading starch, glucan, protein and lipid were highly expressed. CONCLUSIONS: The genome information of R. miehei will facilitate future studies to better understand the mechanisms of fungal thermophilic adaptation and the exploring of the potential of R. miehei in industrial-scale production of thermostable enzymes. Based on the existence of a large repertoire of amylolytic, proteolytic and lipolytic genes in the genome, R. miehei has potential in the production of a variety of such enzymes.

Chronic rhinofacial mucormycosis caused by Mucor irregularis (Rhizomucor variabilis) in India.

In this article, we describe a chronic case of rhinofacial mucormycosis caused by Mucor irregularis, formerly known as Rhizomucor variabilis var. variabilis, a rare mycotic agent in humans. The infection caused progressive destruction of the nasal septum and soft and hard palate, leading to collapse of the nose bridge and an ulcerative gaping hole. The mucoralean mold cultured from a nasal biopsy specimen was determined by multilocus DNA sequence data to be conspecific with M. irregularis.

Primary cutaneous zygomycosis caused by rhizomucor variabilis: a new endemic zygomycosis? A case report and review of 6 cases reported from China.

We report a case of primary cutaneous zygomycosis caused by Rhizomucor variabilis and review 6 cases reported from China that share similar features and are different from those cases caused by other species of Mucorales. It is noteworthy that all 6 of the cases were observed in 3 adjacent provinces of eastern China.

Rhizomucor variabilis var. regularior and Hormographiella aspergillata infections in a leukemic bone marrow transplant recipient with refractory neutropenia.

Rhizomucor variabilis and Hormographiella aspergillata rarely cause human infections. This report details a fatal case of a 14-year-old female with leukemia posthematopoietic cell transplant and relapse with refractory pancytopenia. The patient first developed an R. variabilis var. regularior palate infection and later developed a cutaneous H. aspergillata infection while on posaconazole and caspofungin therapy.

High-affinity iron permease (FTR1) gene sequence-based molecular identification of clinically important Zygomycetes.

The clinical importance of zygomycosis, an emerging and frequently fatal mycotic disease, has increased during recent years. This report describes an identification method based on PCR amplification and sequencing of the high-affinity iron permease 1 gene (FTR1). Primers and amplification protocols were established and tested for the identification of Rhizopus oryzae, Rhizopus microsporus var. rhizopodiformis, R. microsporus var. oligosporus, Rhizopus schipperae, Rhizopus niveus and Rhizopus stolonifer. Rhizomucor and Syncephalastrum could be identified at the genus level. PCR-restriction fragment length polymorphism analysis of the amplified gene fragment using AluI digestion distinguished three subgroups among the R. oryzae isolates.

[Rennet production by Rhizomucor miehei NRRL 3169]. / Producción de renina por Rhizomucor miehei NRRL 3169.

The production of rennet was studied, using different strains of the fungus Rhizomucor miehei. The selection and preservation of strains, type of growth, media design and operation conditions were evaluated. The experiments were carried out in Erlenmeyer flasks in rotary shaker at 250 rpm and 2.5 eccentricity, and in mechanically stirred fermentors of the New Brunswick type, at 30 degrees C. In the studies concerning strain selection, the best strain was Rhizomucor miehei NRRL 3169. The major titles of enzyme were obtained in batch process at 168 h, with 884 SU/ml, whereas in mechanically stirred fermentors the best value was 1160 SU/ml. These values were far more superior to former ones published by various experts.

Characterization of a ß-glucosidase with transgalactosylation capacity from the zygomycete Rhizomucor miehei.

An extracellular ß-glucosidase from the zygomycete Rhizomucor miehei NRRL 5282 cultivated in a wheat bran-based solid state fermentation system was characterized. The purified enzyme exhibited an optimum temperature of 68-70 °C and pH of 5.0. It efficiently hydrolyzed oligosaccharides having ß-(1→4) glycosidic linkages and exhibited some ß- and α-galactosidase activity. The V(max) for p-nitrophenyl-ß-d-glucopyranoside and cellobiose was 468.2 and 115.5 U/mg, respectively, while the K(m) was 0.12 mM for both substrates. The enzyme had transglucosylation and transgalactosylation activities resulting in the formation of glycosides from cellobiose, lactose and ethanol. The enzyme increased the amounts of free phenolic antioxidants in sour cherry pomace indicating that its hydrolyzing activity could potentially be applicable to improve the bioavailability of these compounds.

Cutaneous mucormycosis with necrotising fasciitis in a young immunocompetent individual.

Primary cutaneous mucormycosis is uncommon and is extremely rare in immunocompetent young individuals. Here we report a case of necrotising fasciitis due to mucormycosis in an immunocompetent young individual following minor trauma. Mucormycosis must be suspected in any wound that is worsening despite appropriate treatment even in immunocompetent individuals.

Successful treatment of disseminated mucormycosis with a combination of liposomal amphotericin B and posaconazole in a patient with acute myeloid leukaemia.

The combination of resection of infected tissue and antifungal therapy is the treatment of choice in mucormycosis. In disseminated mucormycosis, where surgery is impossible, the mortality is almost 90%. We report the first case of disseminated mucormycosis that was cured with a combination therapy of liposomal amphotericin B and posaconazole without surgical intervention.

Intraspecific variation in two species of Rhizomucor assessed by random amplified polymorphic DNA analysis.

Twenty-three Rhizomucor isolates were characterized by random amplified polymorphic DNA-PCR (RAPD-PCR) with 10-bp oligonucleotide primers. These data were used for numerical analyses to obtain information on the intraspecific genetic polymorphism of Rhizomucor species. The genetic variability in Rhizomucor pusillus and Rhizomucor miehei isolates was found to differ; the latter revealed less intraspecific polymorphism. The different levels of genotypic diversity suggest a correlation with the different forms of mating behaviour of these species. Rhizomucor tauricus displayed amplification patterns similar to those of the investigated R. pusillus strains, reinforcing the assumption that R. tauricus does not represent a separate species. Characteristic RAPD markers allowing PCR-based species identification of Rhizomucor isolates were determined.

Differentiation of Rhizomucor species on the basis of their different sensitivities to lovastatin.

The opportunistic pathogens Rhizomucor pusillus and Rhizomucor miehei may be agents of frequently fatal mycotic diseases. In the present study, the susceptibilities of 27 clinical and environmental isolates of R. miehei and R. pusillus to lovastatin under different culturing conditions were investigated. Most of the R. miehei strains grew at lovastatin concentrations as high as 64 to 128 microg/ml. In contrast, the inhibitory effect of lovastatin on all of the R. pusillus strains was evident at lovastatin concentrations as low as 1 to 2 microg/ml. A simple and reliable method for species-level differentiation, based on the significantly higher sensitivity of R. pusillus to lovastatin than that of R. miehei, was elaborated. According this, on malt extract agar containing 6 mug of lovastatin/ml, R. pusillus is not able to produce colonies, while R. miehei will form compact colonies.