A Polysaccharide Derived from a Trichosporon sp. Culture Strongly Primes Plant Resistance to Viruses.

Plant viruses cause devastating diseases in plants, yet no effective viricide is available for agricultural application. We screened cultured filtrates derived from various soil microorganisms cultured in vegetable broth that enhanced plant viral resistance. A cultured filtrate, designated F8 culture filtrate, derived from a fungus belonging to the genus Trichosporon, induced strong resistance to various viruses on different plants. Our inoculation assay found the infection rate of Tobacco mosaic virus (TMV)-inoculated Nicotiana benthamiana with F8 culture filtrate pretreatment may decrease to 0%, whereas salicylic acid (SA)-pretreated N. benthamiana attenuated TMV-caused symptoms but remained 100% infected. Tracking Tobacco mosaic virus tagged with green fluorescence protein in plants revealed pretreatment with F8 culture filtrate affected the initial establishment of the virus infection. From F8 culture filtrate, we identified a previously unknown polysaccharide composed of D-mannose, D-galactose, and D-glucose in the ratio 1.0:1.2:10.0 with a α-D-1,4-glucan linkage to be responsible for the induction of plant resistance against viruses through priming of SA-governed immune-responsive genes. Notably, F8 culture filtrate only triggered local defense but was much more effective than conventional SA-mediated systematic acquired resistance. Our finding revealed that microbial cultured metabolites provided a rich source for identification of potent elicitors in plant defense.

The dynamic structure of Spitzenkörpers of Trichosporon asahii examined by the fluorescent probe FM4-64

Abstract The Spitzenkörper is a dynamic and specialized multicomponent cell complex present in the tips of hyphal cells. The amphiphilic styryl dye FM4-64 was found to be ideal for imaging the dynamic changes of the apical vesicle cluster within growing hyphal tips. It is widely used as a marker of endocytosis and to visualize vacuolar membranes. Here we performed uptake experiments using FM4-64 to study the dynamic of the Spitzenkörper in Trichosporon asahii. We observed that Spitzenkörpers were present at the tip of the budding site of the spore, blastospore, and the germ tube of T. asahii. We also found that Spitzenkörpers were present at the tip of the hyphae as well as the subapical regions. Cytochalasin D, an inhibitor of actin polymerization, leads to abnormal Spitzenkörper formation and loss of cell polarity.

Microbial oil production from rice straw hydrolysate by Trichosporon fermentans.

Microbial oil production from sulphuric acid treated rice straw hydrolysate (SARSH) by Trichosporon fermentans was performed for the first time. Fermentation of SARSH without detoxification gave a poor lipid yield of 1.7 g/l, which was much lower than the result with glucose or xylose as the single carbon source (13.6 g/l or 9.9 g/l). The detoxification pretreatment, including overliming, concentration, and adsorption by Amberlite XAD-4 improved the fermentability of SARSH significantly by removing the inhibitors in SARSH. A total biomass of 28.6 g/l with a lipid content of 40.1% (corresponding to a lipid yield of 11.5 g/l) could be achieved after cultivation of T. fermentans on the detoxified SARSH for 8 days. Moreover, besides SARSH, T. fermentans could also utilize mannose, galactose, or cellobiose, in hydrolysates of other natural lignocellulosic materials as the single carbon source to grow and accumulate lipid with a high yield (at least 10.4 g/l). Hence, it is a promising strain for microbial oil production and thus biodiesel preparation from agro-industrial residues, especially lignocellulosic materials.

Morphological and biochemical characterization of the aetiological agents of white piedra

The Trichosporon genus is constituted by many species, of which Trichosporon ovoides and Trichosporon inkin are the causative agents of white piedra. They can cause nodules in genital hair or on the scalp. At present, Brazilian laboratory routines generally do not include the identification of the species of Trichosporon genus, which, although morphologically and physiologically distinct, present many similarities, making the identification difficult. The aim of this study was to identify the aetiological agents at the species level of white piedra from clinical specimens. Therefore, both the macro and micro morphology were studied, and physiological tests were performed. Trichosporon spp. was isolated from 10 clinical samples; T. ovoides was predominant, as it was found in seven samples, while T. inkin was identified just in two samples. One isolate could not be identified at the species level. T. inkin was identified for the first time as a white piedra agent in the hair shaft on child under the age of 10.

Disseminated trichosporonosis in a murine model of chronic granulomatous disease.

Over a period of ten months, five mice submitted to our service (the Pathology Section of the Veterinary Resources Program, Office of Research Services at the National Institutes of Health, Bethesda, Md.) were diagnosed with disseminated trichosporonosis. These mice had pyogranulomatous inflammation in multiple organs, including lung, liver, lymph nodes, salivary gland, and skin. Fungal elements in many of the lesions were identified, using special histochemical stains, and Trichosporon beigelii was obtained by use of culture of specimens at affected sites. This saprophytic fungus has caused disseminated disease in immunosuppressed humans. However, despite widespread use of immunosuppressed rodents in research, to the authors' knowledge, this organism had not previously been reported to cause spontaneous disseminated disease in laboratory mice. All affected mice had a genetically engineered defect in p47(phox), a critical component of the nicotinamide dinucleotide phosphate (NADPH) oxidase, the enzyme responsible for generating the phagocyte oxidative burst. These animals are used as a murine model of human chronic granulomatous disease. We discuss the lesions, differential diagnosis, identification of the organism, and the role of NADPH oxidase in protecting against disseminated trichosporonosis.

Design of novel analogue peptides with potent fungicidal but low hemolytic activity based on the cecropin A-melittin hybrid structure.

In order to design synthetic peptides with potent antifungal activity but low cytotoxic activity under physiological conditions, several analogues of the previously reported cecropin A (CA)-melittin (ME) hybrid peptide, CA(1-8)-ME(1-12), were synthesized. These analogues were designed by analysis of the alpha-helical wheel diagram of CA(1-8)-ME(1-12). Antifungal activities were measured by growth inhibition of the yeast Trichosporon beigelii and by hemolytic assay with human red blood cells, respectively. Substitution of Thr for Lys at position 18 and 19 of CA(1-8)-ME(1-12) caused a dramatic reduction in hemolytic activity. Two analogue peptides (analogue I and III) showed more potent antifungal and lower hemolytic activity than the original peptide. To study the antifungal mechanism of these peptides, fluorescence activated flow cytometry and confocal laser scanning microscopy were performed with the most powerful antifungal analogue I peptide designed in the present study. As determined by propidium iodide staining, fungal cells treated with analogue I or melittin showed higher fluorescence intensity than those treated with the weak antifungal peptide, cecropin A. By confocal microscopy the analogue I was detected in the intracellular region as well as the in cell membrane. These facts suggested that the antifungal function of this novel peptide analogue acts by pore formation in the cell membrane.

Disseminated Trichosporon beigelii infection in patients with malignant diseases: immunohistochemical study and review.

Trichosporon beigelii is a causative agent of opportunistic infection and summer-type hypersensitivity pneumonitis in Japan. However, as the diagnosis of Trichosporon beigelii infection is sometimes difficult, the actual incidence of this disease may be underestimated. Of 203 autopsy patients with malignant disease, seven (7.7%) were diagnosed with disseminated Trichosporon beigelii infection by immunohistochemical investigation of formalin-fixed, paraffin-embedded tissue sections. Including these seven, a total of 43 patients with Trichosporon beigelii infection have been reported in Japan. The majority of them had underlying hematologic malignancies, for which they received cytotoxic chemotherapy resulting in neutropenia. This study indicates that the immunohistochemical method, which can be applied to biopsy specimens, is an excellent tool for specific diagnosis of Trichosporon beigelii infection, which is an emerging fatal mycosis in immunocompromised patients with profound neutropenia.

Trichosporon on humans: a practical account.

Six human pathogenic Trichosporon species are described with respect to criteria for routine identification, epidemiology and clinical origin: T. ovoides, T. inkin, T. asahii, T. asteroides (Fissuricella filamenta), T. cutaneum, and T. mucoides. These species are causative agents of white piedra and cutaneous infections and are involved in systemic, localized or disseminated mycoses, particularly in patients with underlying haematological malignancy. Data on in vitro sensitivity to antifungal drugs are provided.