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Neoformans
Kinds of Neoformans Selected AbstractsStimulation via Toll-like receptor 9 reduces Cryptococcus neoformans -induced pulmonary inflammation in an IL-12-dependent mannerEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 1 2005Lorna Edwards Abstract Cytosine-phosphate-guanosine-containing oligodeoxynucleotides (CpG ODN) are important vaccine adjuvants that promote Th1-type immune responses. Cryptococcus neoformans is a serious human pathogen that replicates in the lung but may disseminate systemically leading to meningitis, particularly in immunocompromised individuals. Immunization of susceptible C57BL/6 mice with CpG ODN deviates the immune response from a Th2- toward a Th1-type response following infection with C. neoformans. CpG also induces IL-12, TNF, MCP-1 and macrophage nitric oxide production. CD4+ and CD8+ T,cells producing IFN-, increase in frequency, while those producing IL-5 decrease. More importantly, pulmonary eosinophilia is significantly reduced, an effect that depends on IL-12 and CD8+ T,cells but not NK cells. CpG treatment also reduces the burden of C. neoformans in the lung, an effect that is IL-12-, NK cell- and T,cell-independent and probably reflects a direct effect of CpG on pathogen opsonization or an enhancement of macrophage antimicrobial activity. An equivalent beneficial effect is also observed when CpG ODN treatment is delivered during established cryptococcal disease. This is the first study documenting that promotion of lung TLR9 signaling using synthetic agonists enhances host defense. Activation of innate immunity has clear therapeutic potential and may even be beneficial in patients with acquired immune deficiency. [source] The single Cdk1-G1 cyclin of Cryptococcus neoformans is not essential for cell cycle progression, but plays important roles in the proper commitment to DNA synthesis and bud emergence in this yeastFEMS YEAST RESEARCH, Issue 5 2010Eric V. Virtudazo Abstract The cell cycle pattern of the pathogenic basidiomycetous yeast Cryptococcus neoformans differs from that of the ascomycetous budding yeast Saccharomyces cerevisiae. To clarify the cell cycle control mechanisms at the molecular level, homologues of cell cycle control genes in C. neoformans were cloned and analyzed. Here, we report on the cloning and characterization of genes coding for CDK1 cyclin homologues, in particular, the C. neoformans G1 cyclin. We have identified three putative CDK1 cyclin homologues and two putative CDK5 (PHO85) cyclin homologues from the genome. Complementation tests in an S. cerevisiae G1 cyclin triple mutant confirmed that C. neoformans CLN1 is able to complement S. cerevisiae G1 cyclin deficiency, demonstrating that it is a G1 cyclin homologue. Interestingly, cells deleted of the single Cdk1-G1 cyclin were viable, demonstrating that this gene is not essential. However, it exhibited aberrant budding and cell division and a clear delay in the initiation of DNA synthesis as well as an extensive delay in budding. The fact that the mutant managed to traverse the G1 to M phase may be due to the activities of Pho85-related G1 cyclins. Also, that C. neoformans had only a single Cdk1-G1 cyclin highlighted the importance of keeping in order the commitment to the initiation of DNA synthesis first and then that of budding, as discussed. [source] Genotype and mating type analysis of Cryptococcus neoformans and Cryptococcus gattii isolates from China that mainly originated from non-HIV-infected patientsFEMS YEAST RESEARCH, Issue 6 2008Xiaobo Feng Abstract Cryptococcosis has been reported to be mostly associated with non-HIV-related patients in China. However, little is known about the molecular characteristics of clinical isolates from the Cryptococcus neoformans species complex in this country. In this study, 115 clinical isolates were included. Molecular type VNI was the most representative (n=103), followed by VGI (n=8), VNIII (n=2), VNIV (n=1), and VGII (n=1). With the exception of a serotype D mating type a isolate, all possessed the MAT, locus. Multilocus sequence typing (MLST) revealed that most Cryptococcus gattii isolates from China shared identical MLST profiles with the most common MLST genotype reported in the VGI group, and the only one VGII isolate resembled the Vancouver Island outbreak minor genotype. The C. gattii strains involved in this study were successfully grouped according to their molecular type and mating types by PCR-restriction fragment length polymorphism (RFLP) analysis of the GEF1 gene. Our results suggest that (1) in China, cryptococcosis is mostly caused by C. neoformans var. grubii (molecular type VNI), and mating type ,; (2) The most common causative agents of C. gattii infection in China are closely related to a widely distributed MLST genotype; and (3) The PCR-RFLP analysis of the GEF1 gene has the potential to identify the molecular and mating types of C. gattii simultaneously. [source] Extracellular glycosylphosphatidylinositol-anchored mannoproteins and proteases of Cryptococcus neoformansFEMS YEAST RESEARCH, Issue 4 2007Richard A. Eigenheer Abstract Extracellular proteins of Cryptococcus neoformans are involved in the pathogenesis of cryptococcosis, and some are immunoreactive antigens that may potentially serve as candidates for vaccine development. To further study the extracellular proteome of the human fungal pathogen Cry. neoformans, we conducted a proteomic analysis of secreted and cell wall-bound proteins with an acapsular strain of Cry. neoformans. Proteins were identified from both intact cells and cell walls. In both cases, extracellular proteins were removed with trypsin or ,-glucanase, and then all proteins/peptides were purified by solid-phase extraction, spin dialysis, and HPLC, and identified by liquid chromatography,mass spectrometry. This study identified 29 extracellular proteins with a predicted N-terminal signal sequence and also a predicted glycosylphosphatidylinositol anchor motif in more than half. Among the novel proteins identified were five glycosylphosphatidylinositol-anchored proteins with extensive Ser/Thr-rich regions but no apparent functional domains, a glycosylphosphatidylinositol-anchored aspartic protease, and a metalloprotease with structural similarity to an elastinolytic metalloprotease of Aspergillus fumigatus. This study suggests that Cry. neoformans has the machinery required to target glycosylphosphatidylinositol-anchored proteins to the cell wall, and it confirms the extracellular proteolytic ability of Cry. neoformans. [source] Contemplating the murine test tube: lessons from natural killer cells and Cryptococcus neoformansFEMS YEAST RESEARCH, Issue 4 2006Kaleb J. Marr Abstract Murine experimentation has provided many useful tools, including the ability to knockout or over-express genes and to perform experiments that are limited by ethical considerations. Over the past century, mice have imparted valuable insights into the biology of many systems, including human immunity. However, although there are many similarities between the immune response of humans and mice, there are also many differences; none is more prominent than when examining natural killer cell biology. These differences include tissue distribution, effector molecules, receptor repertoire, and cytokine responses, all of which have important implications when extrapolating the studies to the human immune responses to Cryptococcus neoformans. [source] Application of proton nuclear magnetic resonance spectroscopy to the study of Cryptococcus and cryptococcosisFEMS YEAST RESEARCH, Issue 4 2006Tania C. Sorrell Abstract Proton nuclear magnetic resonance spectroscopy is a nondestructive technique that identifies chemicals in solution and in living cells. It has been used in cryptococcal research to identify the primary structure of capsular glucuronoxylomannans, link cellular apoptosis susceptibility (CAS) genes to positioning of residues on the mannose backbone of glucuronoxylomannan, and verify that the cryptococcal virulence determinant, phospholipase B, is elaborated in vivo. Promising clinical applications include speciation (Cryptococcus neoformans and Cryptococcus gattii), with preliminary evidence that varieties neoformans and grubii can also be distinguished, non-invasive diagnosis of cerebral cryptococcomas, and, in cases of meningitis, monitoring therapeutic response by analysis of cerebrospinal fluid. [source] Two-component signal transduction in human fungal pathogensFEMS YEAST RESEARCH, Issue 2 2006Michael Kruppa Abstract Signal transduction pathways provide mechanisms for adaptation to stress conditions. One of the most studied of these pathways is the HOG1 MAP kinase pathway that in Saccharomyces cerevisiae is used to adapt cells to osmostress. The HOG1 MAPK has also been studied in Candida albicans, and more recently observations on the Hog1p functions have been described in two other human pathogens, Aspergillus fumigatus and Cryptococcus neoformans. The important, but not surprising, concept is that this pathway is used for different yet similar functions in each of these fungi, given their need to adapt to different environmental signals. Current studies of C. albicans focus upon the identification of two-component signal proteins that, in both C. albicans and S. cerevisiae, regulate the HOG1 MAPK. In C. albicans, these proteins regulate cell wall biosynthesis (and, therefore, adherence to host cells), osmotic and oxidant adaptation, white-opaque switching, morphogenesis, and virulence of the organism. [source] Role of laccase in the biology and virulence of Cryptococcus neoformansFEMS YEAST RESEARCH, Issue 1 2004Xudong Zhu Abstract Laccase is an important virulence factor for the human pathogen, Cryptococcus neoformans. In this review, we examine the structural, biological and genetic features of the enzyme and its role in the pathogenesis of cryptococcosis. Laccase is expressed in C. neoformans as a cell wall enzyme that possesses a broad spectrum of activity oxidizing both polyphenolic compounds and iron. Two paralogs, CNLAC1 and CNLAC2, are present in the fungus, of which the first one expresses the dominant enzyme activity under glucose starvation conditions. Regulation of the enzyme is in response to various environmental signals including nutrient starvation, the presence of multivalent cations and temperature stress, and is mediated through multiple signal transduction pathways. Study of the function and regulation of this important virulence factor has led to further understanding of mechanisms of fungal pathogenesis and the regulation of stress response in the host cell environment. [source] Cryptococcus neoformans capsule biosynthesis and regulationFEMS YEAST RESEARCH, Issue 8 2004Guilhem Janbon Abstract The capsule is certainly the most prominent virulence factor in Cryptococcus neoformans: acapsular strains are avirulent, and capsular polysaccharides have a deleterious effect on the immune system. Until very recently, very few genes involved in capsule biosynthesis had been identified , and this despite the existence of a detailed body of work concerning the capsule's composition, structure and their regulation by environmental factors. The tremendous development of experimental tools and techniques suited to the study of C. neoformans biology together with the sequencing of three complete genomes have, over the last three years, enabled the identification of a number of proteins which participate directly in biosynthesis of the capsule or which regulate its size. Even though this knowledge is still preliminary, it gives us a clearer picture of the various events needed for biosynthesis of this fascinating structure. [source] Cryptococcal infection in sarcoidosisINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 11 2002Khosrow Mehrany MD A 48-year-old man with a history of sarcoidosis was transferred to the Mayo Clinic for evaluation and management of progressive neurologic decline. Two years before admission, he was admitted to a local hospital with mental status changes accompanied by ataxia and severe headache. A diagnosis of pulmonary and central nervous system sarcoidosis was made based on computed tomography of the head, lumbar puncture, and chest radiography. A mediastinoscopy with lymph node biopsy exhibited noncaseating granulomas and negative stains for microorganisms. Prednisone therapy was initiated at 80 mg/day. Clinical improvement was apparent for 13 months during steroid therapy until the slow taper reached a dosage of 20 mg/day. At that time, the patient was readmitted to the local hospital with severe confusion and skin lesions. When intravenous methylprednisolone therapy for presumed central nervous system sarcoidosis did not improve the patient's mental status, he was transferred to the Mayo Clinic. Physical examination of the thighs revealed large, well-marginated, indurated, irregularly bordered, violaceous plaques and rare, umbilicated, satellite papules with central hemorrhagic crusts (Fig. 1A). Superficially ulcerated plaques with a similar appearance to the thigh lesions were coalescing around the lower legs (Fig. 1B). A skin biopsy specimen of the thigh demonstrated abundant numbers of encapsulated organisms and minimal inflammatory response (Fig. 2). Skin, blood, and cerebrospinal fluid cultures confirmed the presence of Cryptococcus neoformans. Amphotericin and flucytosine combination therapy was initiated, and steroid dosages were gradually tapered. A test for human immunodeficiency virus was negative. The patient was dismissed from hospital after a complicated 2-month course resulting in improved mental status but progression of the lower extremity ulcerations as a result of polymicrobial infection. Figure 1. (A) Violaceous plaque with satellite papules on thigh. (B) Ulcerating plaques coalescing around leg Figure 2. (A) Sparse inflammatory infiltrate and abundant encapsulated organisms (hematoxylin and eosin; × 20). (B) Cryptococcal organisms (Gomori's methenamine silver; × 40) [source] Cutaneous cryptococcosis associated with lepromatous leprosyINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 6 2001Rubem David Azulay MD A 65-year-old Brazilian man presented with an erythematous nodular lesion on the left forearm (Fig. 1). The patient had been treated with multidrug therapy for 8 months for lepromatous leprosy. During therapy, he developed recurrent episodes of reactions which were treated with high doses of prednisone and thalidomide. The histopathology of the cutaneous nodular lesion showed a granulomatous inflammatory infiltrate; some histiocytes contained vacuolations and others demonstrated oval-like or coma-like structures (Fig. 2). The specimen was cultivated in Sabouraud agar at room temperature. The colonies were transferred to Petri dishes containing Niger Seed Agar (NSA) (Fig. 3). The confirmed diagnosis was Cryptococcus neoformans var. neoformans based on microscopy and physiology, including the canavanine,glycine,bromothymol blue (CGB) medium (Lazéra MS, Pires FDA, Camillo-Coura L et al. Natural habitat of Cryptococcus neoformans var. neoformans in decaying wood forming hollows in living trees. J Med Vet Mycol 1996; 34: 127,131). The liquor culture was negative. Hemoculture and urine culture were also negative. Latex agglutination test was blood positive and liquor negative. Figure 1. Erythematous nodular lesion on the left forearm measuring 9 cm in diameter Figure 2. Granulomatous infiltrate presenting oval-like or coma-like structures inside the histiocytes (mucicarmine stain, ×,100) Figure 3. Petri dishes with Niger Seed Agar containing numerous colonies of Cryptococcus neoformans var. neoformans The patient's hemogram revealed normocytic anemia and normal total and differential white blood count. The CD4 count was 189/m3 and the CD8 count was 141/m3. Serology for anti-human immunodeficiency virus-I (anti-HIV-I) antibodies was negative. The X-ray of the lungs showed an areolar image in the superior lobe of the right lung. Therapy with prednisone was suspended and fluconazole (300 mg/day) was prescribed. The nodular cutaneous lesion regressed completely after 90 days. The patient was submitted to a second skin biopsy for treatment control. The culture of the specimen taken was still positive and the histopathology showed the same picture as before treatment. After 5 months of continued therapy with fluconazole, another biopsy was performed but no fungus was recovered from the specimen. [source] Cyanobacteria from benthic mats of Antarctic lakes as a source of new bioactivitiesJOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2008N. Biondi Abstract Aims:, To exploit the cyanobacterial diversity of microbial mats growing in the benthic environment of Antarctic lakes for the discovery of novel antibiotic and antitumour activities. Methods and results:, In all, 51 Antarctic cyanobacteria isolated from benthic mats were cultivated in the laboratory by optimizing temperature, irradiance and mixing. Productivity was generally very low (,60 mg l,1 d,1) with growth rates (,) in the range of 0·02,0·44 d,1. Growth rates were limited by photosensitivity, sensitivity to air bubbling, polysaccharide production or cell aggregation. Despite this, 126 extracts were prepared from 48 strains and screened for antimicrobial and cytotoxic activities. Seventeen cyanobacteria showed antimicrobial activity (against the Gram-positive Staphylococcus aureus, the filamentous fungus Aspergillus fumigatus or the yeast Cryptococcus neoformans), and 25 were cytotoxic. The bioactivities were not in accordance with the phylogenetic grouping, but rather strain-specific. One active strain was cultivated in a 10-l photobioreactor. Conclusions:, Isolation and mass cultivation of Antarctic cyanobacteria and LC-MS (liquid chromatography/mass spectrometry) fractionation of extracts from a subset of those strains (hits) that exhibited relatively potent antibacterial and/or antifungal activities, evidenced a chemical novelty worthy of further investigation. Significance and impact of the study:, Development of isolation, cultivation and screening methods for Antarctic cyanobacteria has led to the discovery of strains endowed with interesting antimicrobial and antitumour activities. [source] Inhibition of clinical and environmental Cryptococcus neoformans isolates by two Brazilian killer yeastsJOURNAL OF BASIC MICROBIOLOGY, Issue 2 2006Alexandre M. Fuentefria Two killer yeast strains (HB55 and HB88) capable of inhibiting human pathogenic fungi were isolated from leaves of Hibiscus rosa-sinensis in Brazil. These isolates were identified by conventional methods and sequencing of the D1/D2 region of the 26S rDNA as Kodamaea ohmeri . They inhibited all Cryptococcus neoformans (vars. neoformans , grubii and gattii ) strains tested, including reference, clinical and environmental isolates. The killer phenotype was not cured by thermal treatment. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Preemptive treatment of fungal infection: has its time arrived in liver transplantation?LIVER TRANSPLANTATION, Issue 3 2008James D. Perkins M.D. Special Editor Background Invasive fungal infection remains a major challenge in liver transplantation and the mortality rate is high. Early diagnosis and treatment are required for better results. Patients We prospectively measured plasma (1 , 3),-d glucan (BDG) levels in 180 living donor liver transplant recipients for 1 year after surgery. Fungal infection was defined as proposed by the European Organization for Research and Treatment of Cancer/Mycoses Study Group. Preemptive treatment (intravenous fluconazole and trimethoprim-sulfamethoxazole) was started when the BDG level was greater than 40 pg/ml. Results Twenty-four patients (13%) were diagnosed with invasive fungal infection. The responsible pathogens included Candida spp. in 14 cases, Aspergillus fumigatus in 5, Cryptococcus neoformans in 3, and Pneumocystis jiroveci in 2. Preemptive treatment was performed in 22% of patients (n = 40). Renal impairment and mild gastrointestinal intolerance due to the drugs were observed in 28% (11/40) of patients during treatment. Among them 14 patients were diagnosed with fungal infection including seven candidiasis, five aspergillosis, and two Pneumocystis jiroveci pneumonia. The sensitivity and specificity of BDG for overall fungal infection was 58% and 83%, respectively, with a positive predictive value of 35% and a negative predictive value of 93%, and a positive likelihood ratio of 3.41 and a negative likelihood ratio of 1.98. The overall mortality for fungal infection in our series was 0.6%. Conclusion Although the sensitivity and positive predictive value were low, the low mortality rate after fungal infection and the mild side effects of the preemptive treatment might justify our therapeutic strategy. Based on the effectiveness, this strategy warrants further investigation. [source] Cell wall ,-1,3-glucan is required to anchor the Cryptococcus neoformans capsuleMOLECULAR MICROBIOLOGY, Issue 4 2003Amy J. Reese Summary Cryptococcus neoformans is an opportunistic pathogen responsible for serious disease in humans. Critical for virulence of this fungus is an elaborate polysaccharide capsule, which impedes the host immune response. We found that association of the capsule with the cell requires a specific component of the cell wall, ,-1,3-glucan. Post-transcriptional inhibition of ,-1,3-glucan synthase expression, using double-stranded RNA interference, yields cells that are unable to assemble a capsule although they generate its polysaccharide components. The resulting cryptococci are slow-growing and acapsular. This finding demonstrates a novel mode of polysaccharide attachment and an important application of RNA interference in fungi. The elimination of the capsule by reducing the expression of a single gene suggests a potential avenue for antifungal chemotherapy. [source] The Cryptococcus neoformans MAP kinase Mpk1 regulates cell integrity in response to antifungal drugs and loss of calcineurin functionMOLECULAR MICROBIOLOGY, Issue 5 2003Peter R. Kraus Summary Cell wall integrity is crucial for fungal growth, development and stress survival. In the model yeast Saccharomyces cerevisiae, the cell integrity Mpk1/Slt2 MAP kinase and calcineurin pathways monitor cell wall integrity and promote cell wall remodelling under stress conditions. We have identified the Cryptococcus neoformans homologue of the S. cerevisiae Mpk1/Slt2 MAP kinase and have characterized its role in the maintenance of cell integrity in response to elevated growth temperature and in the presence of cell wall synthesis inhibitors. C. neoformans Mpk1 is required for growth at 37°C in vitro, and this growth defect is suppressed by osmotic stabilization. C. neoformans mutants lacking Mpk1 are attenuated for virulence in the mouse model of cryptococcosis. Phosphorylation of Mpk1 is induced in response to perturbations of cell wall biosynthesis by the antifungal drugs nikkomycin Z (a chitin synthase inhibitor), caspofungin (a ,-1,3-glucan synthase inhibitor), or FK506 (a calcineurin inhibitor), and mutants lacking Mpk1 display enhanced sensitivity to nikkomycin Z and caspofungin. Lastly, we show that calcineurin and Mpk1 play complementing roles in regulating cell integrity in C. neoformans. Our studies demonstrate that pharmacological inhibition of the cell integrity pathway would enhance the activity of antifungal drugs that target the cell wall. [source] Copper-mediated reversal of defective laccase in a ,vph1 avirulent mutant of Cryptococcus neoformansMOLECULAR MICROBIOLOGY, Issue 4 2003Xudong Zhu Summary Previous studies have shown that a ,vph1 Cryptococcus neoformans mutant defective in vesicular acidification lacked several important virulence factors including a copper-containing laccase and was avirulent in a mouse model. In the present studies, we characterized laccase transcription and protein production to obtain insights into the mechanism of the vph1 mutation in this pathogen. Although transcription and protein expression were somewhat reduced, laccase protein was found to be successfully translated and correctly targeted to the cell wall in the ,vph1 mutant as shown by Western blot and immuno-electron microscopy, despite a complete lack of laccase activity. Laccase activity was substantially restored in metabolically active ,vph1 cells at 30°C by addition of 100 µM copper sulphate. This restoration by copper was found to occur through both transcriptional and post-translational mechanisms. Laccase transcriptional induction by copper was found to be dependent on enhancer region II within the 5,-untranslated region of CNLAC1. Copper was also found to restore partial activity to ,vph1 cells at 0°C, suggesting that cell wall laccase was expressed in the mutant as an apo-enzyme. Apo-laccase restoration by copper was found to be facilitated by an acidic environment, consistent with a role for the vacuolar (H+)-ATPase proton pump in copper assembly of laccase in C. neoformans. [source] Multiple virulence factors of Cryptococcus neoformans are dependent on VPH1MOLECULAR MICROBIOLOGY, Issue 4 2001Todd Erickson Acidification of vesicular compartments plays an important role in a number of cellular transport processes, including protein secretion, metal cofactor insertion, glycosylation and pH stability. In the present study, we identify and characterize a component of the vesicular proton pump, Vph1p, to determine its role in the virulence of the AIDS-related fungal pathogen Cryptococcus neoformans. Insertional mutagenesis and plasmid rescue were used to identify the VPH1 gene by screening for mutants defective in laccase activity. Disruption of VPH1 resulted in defects in three virulence factors (capsule production, laccase and urease expression), as well as a growth defect at 37°C, but only a small growth reduction at 30°C. These effects were duplicated by the vacuolar (H+)-ATPase inhibitor bafilomycin A1. Furthermore, the vph1 insertional mutant was also avirulent in a mouse meningo-encephalitis model. Complementation of the insertional mutant with wild-type VPH1 resulted in a recovery of virulence factor expression, normal growth at 37°C and restoration of full virulence. These studies establish the importance of the VPH1 gene and vesicular acidification in the virulence of C. neoformans. [source] Calcineurin regulatory subunit is essential for virulence and mediates interactions with FKBP12,FK506 in Cryptococcus neoformansMOLECULAR MICROBIOLOGY, Issue 4 2001Deborah S. Fox Calcineurin is a Ca2+,calmodulin-regulated protein phosphatase that is the target of the immunosuppressive drugs cyclosporin A and FK506. Calcineurin is a heterodimer composed of a catalytic A and a regulatory B subunit. In previous studies, the calcineurin A homologue was identified and shown to be required for growth at 37°C and hence for virulence of the pathogenic fungus Cryptococcus neoformans. Here, we identify the gene encoding the calcineurin B regulatory subunit and demonstrate that calcineurin B is also required for growth at elevated temperature and virulence. We show that the FKR1-1 mutation, which confers dominant FK506 resistance, results from a 6 bp duplication generating a two-amino-acid insertion in the latch region of calcineurin B. This mutation was found to reduce FKBP12,FK506 binding to calcineurin both in vivo and in vitro. Molecular modelling based on the FKBP12,FK506,calcineurin crystal structure illustrates how this mutation perturbs drug interactions with the phosphatase target. In summary, our studies reveal a central role for calcineurin B in virulence and antifungal drug action in the human fungal pathogen C. neoformans. [source] Characterisation of the CipC-like protein AFUA_5G09330 of the opportunistic human pathogenic mould Aspergillus fumigatusMYCOSES, Issue 4 2010Bettina Bauer Summary,Aspergillus fumigatus is currently the major airborne fungal pathogen that menaces immunocompromised individuals. Germination of inhaled conidia is a hallmark of the early infection process, but little is known about the underlying mechanisms. The intention of our ongoing studies is the identification of A. fumigatus proteins that are differentially expressed during germination and may provide insights in the germination process. Using a proteomic approach, we identified AFUA_5G09330 as a major hyphal-specific protein. This result was confirmed using monoclonal antibodies generated in this study. AFUA_5G09330 belongs to a fungal-specific protein family. The eponymous CipC protein of A. nidulans has been shown to be induced by concanamycin A, and transcriptional data from Cryptococcus neoformans demonstrate a strong up-regulation of the expression of a homologous gene during infection. Our data provide evidence that AFUA_5G09330 is a monomeric, cytoplasmic protein. We found no evidence for an overexpression of AFUA_5G09330 induced by concanamycin A or other stress conditions. AFUA_5G09330 is exclusively found in the hyphal morphotype that enables an invasive growth of A. fumigatus during infection. Further studies are required to define the biological function of this hyphae-specific protein and its potential relevance for the pathogenicity of A. fumigatus. [source] Müeller,Hinton methylene blue media as an alternative to RPMI 1640 for determining the susceptibility of Cryptococcus neoformans and Cryptococcus gattii to posaconazole with EtestMYCOSES, Issue 2 2010Eidi Alvarado-Ramírez Summary Mueller,Hinton modified agar (MH-GMB) was compared with RPMI + 2% glucose,agar to determine the MICs of 80 isolates of Cryptococcus neoformans and C. gattii to posaconazole with Etest. MH-GMB minimised trailing and agreement between both media was 94%. Agreement of M27-A2 microbroth reference method was 98% with RPMI and 94% with MB-GMB. [source] Detection of IgM and IgG antibodies to Cryptococcus neoformans proteins in blood donors and HIV patients with active cryptococcosisMYCOSES, Issue 2 2009H. C. Chai Summary The serological responses to Cryptococcus neoformans proteins of blood donors and HIV patients with active cryptococcosis from a tropical region were investigated in this study. Exposure to C. neoformans, an organism ubiquitous in the environment, contributes to the antibody responses observed in the blood donors. IgG responses to cryptococcal proteins were stronger than IgM responses in most sera tested in this study. A 53-kDa cryptococcal protein fragment was identified as the most immunoreactive protein on the IgM immunoblots of both blood donors and patients. Overall, there was no obvious difference in IgG responses of patients when compared with blood donors. Some immunogenic protein fragments (27.5, 76, 78 and 91.5 kDa) were detected at least two times more frequently on IgM immunoblots of patients compared with those of blood donors. It is yet to be investigated whether the proteins identified in this study may have any potential to be used as biomarker for cryptococcosis. [source] Use of magnetic beads to extract fungal DNAMYCOSES, Issue 1 2005E. Faggi Summary Authors compare two methods of extracting DNA from different fungi: the classic method with phenol/chloroform (P/C) and that with magnetic beads. Both were tested on Candida albicans and Cryptococcus neoformans var. neoformans, belonging to the yeast group and Microsporum canis, M. gypseum, Trichophyton rubrum, T. interdigitale, T. ajelloi, Epidermophyton floccosum, belonging to the dermatophytes group. Extraction products underwent polymerase chain reaction (PCR) fingerprinting with the appropriate primers to point out any disagreement in the genomic profiles. After having determined that the genomic profiles obtained from the DNA extracted from the same strain with the two methods correspond perfectly, the authors concluded that the extraction method with magnetic beads from fungal cells is simpler and quicker than with P/C extraction, greatly facilitating the obtainment of fungal DNA. [source] Comparative evaluation of Candi Select test and conventional methods for identification of Candida albicans in routine clinical isolatesMYCOSES, Issue 3-4 2002S. Foongladda Candida albicans; Identifizierung; Candi Select- Test; Bewertung. Summary. The Candi Select test (Sanofi Diagnostics, Pasteur, Marnes-La-Coquette, France) is a new yeast-selective medium for the identification of Candida albicans in the clinical laboratory. The performance of this test was compared with the conventional methods of chlamydospore formation, germ tube formation and carbohydrate fermentation. Four hundred and twenty clinical yeast isolates from 412 fresh clinical specimens, including 283 C. albicans, 59 C. tropicalis, 39 Trichosporon spp., 19 C. glabrata, 11 Cryptococcus neoformans and 9 other yeasts, were evaluated. Colonies of C. albicans produced a blue-green colour on the Candi Select media which could be distinguished from the other yeasts with the naked eye within 24,48 h. The sensitivity and specificity of the Candi Select test for the identification of C. albicans were 99.65% and 97.08%, respectively. The blue-green colonies of C. albicans were easy to identify and recognize in mixed cultures and did not need detailed microscopic examination. Zusammenfassung., Der Candi Select-Test (Sanofi Diagnostics Pasteur, Marnes-La-Coquette, Frankreich) ist ein neuer selektiver Nährboden für die Identifizierung von Candida albicans im klinischen Labor. Die neue Methode wurde mit den konventionellen Methoden der Chlamydosporenbildung, der Keimschlauchbildung und der Kohlenhydrat-Gärung verglichen. Vierhundertzwanzig Hefeisolate, nämlich 283 C. albicans, 59 Candida tropicalis, 39 Trichosporon spp., 19 Candida glabrata, 11 Cryptococcus neoformans und 9 andere Hefen, isoliert aus 412 frischen klinischen Untersuchungsproben, wurden mit allen Methoden untersucht. Mit blossem Auge erkennbar, unterschieden sich innerhalb von 24,48 Stunden die blau-grünen Farbkolonien von C. albicans von allen anderen Hefen auf dem Candi Select Nährboden. Sensitivität und Spezifizität des Candi Select Tests für die Identifizierung von C. albicans betrugen 99.65% und 97.08%. Die blau-grünen Farbkolonien von C. albicans waren in den Mischkulturen leicht zu identifizieren, eine mikroskopische Untersuchung erübrigt sich daher. [source] Occurrence of Cryptococcus spp. in excreta of pigeons and pet birdsMYCOSES, Issue 1-2 2000Kielstein In pooled samples of faeces from 25 pet bird flocks in Thuringia, a high rate of contamination with Cryptococcus neoformans var. neoformans was found. The prevalence of Cr. neoformans in the bird-breeding establishments correlated with the numbers of the different pet bird species in these flocks. The differentiation between varieties of Cr. neoformans by means of proline assimilation and canavanine resistance detection as well as with the aid of Cr. neoformans factor sera, polymerase chain reaction (PCR) fingerprinting, sequencing of PCR products as well as Fourier transform infrared spectroscopy showed uniform results which also corresponded to the serological differentiation between serovars A and D. A predominance of serovar A could be observed among the pet bird breeding flocks. This corresponded to the frequency distribution of serovars A and D in cases of human diseases in Germany. In 50% of the samples of pigeon excreta examined (n=30) in Innsbruck (Austria), Cryptococcus albidus could be isolated but not Cr. neoformans. However, this Cryptococcus species is of minor pathogenetic importance for man. Cryptococcus albidus may be clearly distinguished from Cr. neoformans by means of microbiological methods, PCR and Fourier transform infrared spectroscopy. [source] Cerebral mycosis: 7-year retrospective series in a tertiary centerNEUROPATHOLOGY, Issue 3 2010Kirtee Raparia This study focuses on the epidemiology, clinical manifestations, risk factors, diagnosis and outcome of all cases of central nervous system (CNS) fungal infections in a tertiary center. Medical records of 18 patients of culture-proven CNS fungal infections were retrospectively reviewed from 2000 to 2007, including 12 isolated from the cerebrospinal fluid (CSF) and seven from tissue biopsy. Patient demographic data included 10 males and eight females. The mean age was 55 years (range: 24,89 years). All but one patient were immunocompromised. Fungal organisms isolated from CSF included: Cryptococcous neoformans (8 patients), Coccidioides immitis (3 patients), and Aspergillus versicolor (1 patient). Histopathology of seven biopsy cases revealed groups of pigmented golden-brown fungal forms in three cases; three cases showed septate fungi, two of which had melanin in their walls; and one case showed multiple round spherules. These cases on microbiological cultures grew Coccidioides immitis (1 patient), Aspergillus fumigatus (1 patient), Cladophialophora bantiana (2 patients), Fonsecaea monophora (1 patient) and Scedosporium apiospermum (2 patients). Five of the seven fungal organisms isolated from tissue biopsies were dematiaceous fungi. Twelve patients died after a period of a few weeks to months, two were lost to follow-up, and four are alive with severe neurological sequelae. CNS fungal infections in our cohort were more common in patients post-transplant and with hematologic malignancies. In our series, rare dematiaceous fungi are emerging agents for cerebral mycosis. The outcome of CNS fungal infections is poor despite vigorous antifungal therapy. [source] In Vitro antifungal activity of extract and plumbagin from the stem bark of Diospyros crassiflora Hiern (Ebenaceae)PHYTOTHERAPY RESEARCH, Issue 7 2007J. P. Dzoyem Abstract In this study the methanol/dichloromethane (1:1) extract and plumbagin isolated from extract of stem barks of Diospyros crassiflora were tested for their antifungal activity against 12 strains of yeast pathogens and filamentous fungi: Candida albicans, Candida glabrata, Candida krusei, Candida tropicalis, Cryptococcus neoformans, Aspergillus niger, Aspergillus flavus, Alternaria sp., Cladosporium sp., Geotrichum candidum, Fusarium sp. and Penicillium sp. The growth of all fungi strains tested was inhibited by the extract and plumbagin. The diameter of inhibition zones varied from 12 to 18 mm and from 21 to 35 mm for the extract and plumbagin, respectively. The MIC values ranged from 12.5 to 25 mg/mL for the extract and 0.78,3.12 µg/mL for plumbagin. It is therefore suggested that extracts from the stem bark of Diospyros crassiflora could be used traditionally in the treatment of fungal infections. Compared with ketoconazole used as a standard antifungal, plumbagin could be considered as a promising antifungal agent. Copyright © 2007 John Wiley & Sons, Ltd. [source] HIV-associated opportunistic pneumoniasRESPIROLOGY, Issue 4 2009Laurence HUANG ABSTRACT Among the HIV-associated pulmonary complications, opportunistic pneumonias are major causes of morbidity and mortality. The spectrum of HIV-associated opportunistic pneumonias is broad and includes bacterial, mycobacterial, fungal, viral and parasitic pneumonias. Bacterial pneumonia is the most frequent opportunistic pneumonia in the United States and Western Europe while tuberculosis is the dominant pathogen in sub-Saharan Africa. With the use of combination antiretroviral therapy and prophylaxis, the incidence of Pneumocystis pneumonia (PCP) has declined. Nevertheless, PCP continues to occur in persons who are unaware of their HIV infection, those who fail to access medical care, and those who fail to adhere to antiretroviral therapy or prophylaxis. Although pneumonias due to Cryptococcus neoformans, Histoplasma capsulatum, Coccidioides immitis, cytomegalovirus and Toxoplasma gondii are less frequent, their presence in the lung is often indicative of disseminated disease and is associated with significant mortality. [source] Cellulitis Revealing a Cryptococcosis-Related Immune Reconstitution Inflammatory Syndrome in a Renal Allograft RecipientAMERICAN JOURNAL OF TRANSPLANTATION, Issue 12 2007F. Lanternier Immune reconstitution inflammatory syndrome (IRIS) has rarely been described in the course of disseminated cryptococcosis in solid organ transplant recipients. We report here the case of a renal transplant recipient who developed severe cellulitis in the context of Cryptococcus neoformans -associated IRIS while undergoing reduction of his immunosuppressive therapy. IRIS appeared concomitantly with a dramatic increase of blood CD4+ T cells (94,460/mm3) and required the administration of a short-term steroid therapy to resolve. [source] A novel monoclonal antibody recognizing ,(1,3) glucans in intact cells of Candida and Cryptococcus,APMIS, Issue 10 2008N. KONDORI The cell walls of all medically important fungi contain a unique polyglucose compound, ,(1,3) glucan. In the present study, murine monoclonal antibodies were produced against linear and ,(1,6) branched ,(1,3) glucans, and their specificities were characterized for reactivity to other , glucans, fungal cell wall fragments, and fungal cells. Their reactivity was also compared with that of rabbit polyclonal antibodies raised against the same immunogens. Two mouse monoclonal antibodies (AG and BG) recognized immunoreactive epitopes in ,(1,3)(1,6) glucan by ELISA. In an inhibition assay of the anti-,(1,3)(1,6) activity of the monoclonals, the homologous antigen effectively inhibited the activity as expected, while ,(1,3) also inhibited the assay but to a much lesser extent. No inhibition was obtained by ,(1,3)(1,4) or ,(1,6), while a cell wall extract of Candida albicans (PPM) effectively inhibited both monoclonals. Cell wall fragments of C. albicans (CaCW) and Cryptococcus neoformans (CnCW) inhibited the anti-,(1,3)(1,6) activity of AG, while BG was much less or not inhibited at all. Immunofluorescence confirmed the unique antibody specificity of AG by its recognition of a ,(1,3)(1,6)-associated epitope on the cell surfaces of C. albicans,C. krusei, C. glabrata, and nonencapsulated C. neoformans. The epitope for the AG antibody is suggested to be present in the branching point of ,(1,3)(1,6), or in the randomly coiled ,(1,3) polyglucan due to the presence of branches. Thus, monoclonal antibodies to ,(1,3)(1,6) glucans may have potential as tools in the laboratory diagnosis of invasive yeast infections. [source] | ||||||||||||||||