TY - JOUR. T1 - Monoclonal antibodies can affect complement deposition on the capsule of the pathogenic fungus Cryptococcus neoformans by both classical pathway activation and steric hindrance. AU - Zaragoza, Oscar. AU - Casadevall, Arturo. N1 - Copyright: Copyright 2008 Elsevier B.V., All rights reserved.. PY - 2006/12. Y1 - 2006/12. N2 - The capsule of the human pathogenic fungus Cryptococcus neoformans presents the immune system with a formidable problem for phagocytosis. Capsule-mediated activation of the alternative complement (C) pathway results in component 3 (particularly, C3) binding to the capsule near the cell wall surface. Hence, for cells with large capsule, C3 cannot interact with the complement receptor (CR) and is not opsonic. However, C activation in either immune serum or in the presence of monoclonal antibody (mAb) to capsular polysaccharide localizes C3 to the capsular edge. When C.neoformans cells were coated with both C and antibody (Ab) opsonins, Ab bound first and ...
Amplified fragment length polymorphism (AFLP) genotyping of isolates of the pathogenic fungus Cryptococcus neoformans suggested a considerable genetic divergence between the varieties C. neoformans var. neoformans and C. neoformans var. grubii on the one hand versus C. neoformans var. gattii on the other. This divergence is supported by additional phenotypic, biochemical, clinical and molecular differences. Therefore, the authors propose the existence of two species, C. neoformans (Sanfelice) Vuillemin and C. bacillisporus Kwon-Chung, which differ in geographical distribution, serotypes and ecological origin. Within each species three AFLP genotypes occur, which differ in geographical distribution and serotypes. Differences in ecological origin (AIDS patients, non-AIDS patients, animals or the environment) were found to be statistically not significant. In C. neoformans as well as in C. bacillisporus one of the genotypes represented a hybrid. The occurrence of hybridization has consequences for the
The lysis of infected cells by disease-causing microorganisms is an efficient but risky strategy for disseminated infection, as it exposes the pathogen to the full repertoire of the hosts immune system. Cryptococcus neoformans is a widespread fungal pathogen that causes a fatal meningitis in HIV and other immunocompromised patients. Following intracellular growth, cryptococci are able to escape their host cells by a non-lytic expulsive mechanism that may contribute to the invasion of the central nervous system. Non-lytic escape is also exhibited by some bacterial pathogens and is likely to facilitate long-term avoidance of the host immune system during latency. Here we show that phagosomes containing intracellular cryptococci undergo repeated cycles of actin polymerisation. These actin flashes occur in both murine and human macrophages and are dependent on classical WASP-Arp2/3 complex mediated actin filament nucleation. Three dimensional confocal imaging time lapse revealed that such flashes ...
TY - JOUR. T1 - Radial mass density, charge, and epitope distribution in the Cryptococcus neoformans capsule. AU - Maxson, Michelle E.. AU - Dadachova, Ekaterina. AU - Casadevall, Arturo. AU - Zaragoza, Oscar. N1 - Copyright: Copyright 2008 Elsevier B.V., All rights reserved.. PY - 2007/1. Y1 - 2007/1. N2 - Exposure of Cryptococcus neoformans cells to gamma radiation results in a gradual release of capsnlar polysaccharide, in a dose-dependent manner. This method allows the systematic exploration of different capsular regions. Using this methodology, capsule density was determined to change according to the radial distribution of glacuronoxylomaman and total polysaccharide, becoming denser at the inner regions of the capsule. Scanning electron microscopy of cells following gamma radiation treatment confirmed this finding. The zeta potential of the capsule also increased as the capsule size decreased. However, neither charge nor density differences were correlated with any change in sugar ...
MELO, Natalina Takahashi de et al. Biotyping of Cryptococcus neoformans. Review of the literature. New epidemiologic informations about cryptococcosis. Our experience with the utilization of C.G.B medium in this yeast. Rev. Inst. Med. trop. S. Paulo [online]. 1993, vol.35, n.5, pp.469-478. ISSN 1678-9946. http://dx.doi.org/10.1590/S0036-46651993000500015.. The purpose of this work was to collect the main information from the literature about the biotyping of Cryptococcus neoformans. The more up-to date research concerning the epidemiology of cryptococcosis comprising quite a few articles, mainly after the advent of AIDS, was also reviewed. The Cryptococcus neoformans varieties neoformans and gattii are well defined biochemically nowadays chiefly through the C.G.B. medium, according to KWON-CHUNG et al. (1982)24. The isolation of C. neoformans var. gattii from flowers and leaves of Eucalyptus camaldulensis and Eucalyptus tereticornis, specially in Australia, through the works of ELLIS & PFEIFFER ...
TY - JOUR. T1 - First identification of autochthonous Cryptococcus neoformans var. gattii isolated from goats with predominantly severe pulmonary disease in Spain. AU - Baró, Teresa. AU - Torres-Rodríguez, Josep M.. AU - De Mendoza, Miguel Hermoso. AU - Morera, Yolanda. AU - Alía, Concepción. PY - 1998/2/1. Y1 - 1998/2/1. N2 - Cryptococcus neoformans var. gattii is associated with Eucalyptus trees growing in various tropical and subtropical regions of the world. The identification of 13 autochthonous strains of C. neoformans var. gattii in Spain is reported. These strains were isolated from lung (10 samples), liver (1 sample), and brain (2 samples) tissue specimens from six goats suffering from predominantly severe pulmonary disease that were autopsied. The animals were members of five different herds of goats grazing in rural areas of the province of Caceres (Extremadura, Spain). Between 1990 and 1994, there were five outbreaks, in which between 2.5 and 12% of the goats were affected. ...
TY - JOUR. T1 - Cryptococcus neoformans virulence is enhanced after growth in the genetically malleable host Dictyostelium discoideum. AU - Steenbergen, Judith N.. AU - Nosanchuk, Joshua D.. AU - Malliaris, Stephanie D.. AU - Casadevall, Arturo. N1 - Copyright: Copyright 2008 Elsevier B.V., All rights reserved.. PY - 2003/9/1. Y1 - 2003/9/1. N2 - Cryptococcus neoformans is an encapsulated, environmental fungus that can cause life-threatening meningitis. Pathogenicity of C. neoformans for macrophages and vertebrate hosts may be a mechanism selected in evolution for protection against environmental predators. In this study, we investigated whether Dictyostelium discoideum could serve as an alternate host for C. neoformans. D. discoideum has a defined genetic system which provides significant advantages for the study of fungus-amoeba interactions. Our results show that D. discoideum is susceptible to infection with C. neoformans and that the interactions are similar to those described previously ...
Cryptococcus neoformans var. grubii ATCC ® 208821D-2™ Designation: Genomic DNA from Cryptococcus neoformans var. grubii strain H99JP [ATCC ® 208821™] Application:
Cryptococcus neoformans serotype A is responsible for the majority of cryptococcal infections in AIDS patients. In France, approximately 17% of the patients
TY - JOUR. T1 - Antibody-mediated immobilization of Cryptococcus neoformans promotes biofilm formation. AU - Robertson, Emma J.. AU - Casadevall, Arturo. N1 - Copyright: Copyright 2012 Elsevier B.V., All rights reserved.. PY - 2009/4. Y1 - 2009/4. N2 - Most microbes, including the fungal pathogen Cryptococcus neoformans, can grow as biofilms. Biofilms confer upon microbes a range of characteristics, including an ability to colonize materials such as shunts and catheters and increased resistance to antibiotics. Here, we provide evidence that coating surfaces with a monoclonal antibody to glucuronoxylomannan, the major component of the fungal capsular polysaccharide, immobilizes cryptococcal cells to a surface support and, subsequently, promotes biofilm formation. We used time-lapse microscopy to visualize the growth of cryptococcal biofilms, generating the first movies of fungal biofilm growth. We show that when fungal cells are immobilized using surface-attached specific antibody to the capsule, ...
Strains and cell growth: C. neoformans was grown with continuous shaking at 30° in YPD medium [1% (w/v) Bacto yeast extract; 2% (w/v) peptone, 2% dextrose] or minimal medium lacking uracil (Ausubelet al. 2001). Low adenine plates contained yeast nitrogen base supplemented with (per liter) 20 g glucose; 24 mg uracil; 40 mg each arginine, histidine, isoleucine, leucine, lysine, methionine, and tryrosine; 60 mg phenylalanine and tryptophan; 120 mg homoserine; 180 mg valine; and 10 mg adenine. For experiments using 5-fluoroorotic acid (5-FOA), plates contained the same medium with adenine raised to 40 mg/liter and the addition of 1 g/liter 5-FOA. Wild-type serotype D strain B4500 and cap59 strain TYCC33 (Chang and Kwon-Chung 1994) were from Dr. June Kwon-Chung (National Institutes of Health), and ura5 strain JEC43 (Wickeset al. 1997) was from Dr. Joseph Heitman (Duke University Medical Center). JEC43 cells transformed with a control plasmid alone (CIP-GUST.Cla.Kpn; see below) are designated ...
We have recently identified peptide mimetics of the Cryptococcus neoformans capsular polysaccharide by screening phage display peptide libraries. 2H1, one of a large family of mAbs against the glucuronoxylomannan fraction (GXM), is highly protective and binds several peptide motifs. This study analyzes the immunologic properties of P601E (SYSWMYE), a peptide from the low affinity motif (W/YXWM/LYE) that has an extended cross-reactivity among anti-GXM mAbs and whose binding correlates with the protective potential of mAbs in experimental infection. P601E is a mimetic, since it competes for GXM binding to 2H1, but not a mimotope, since it does not elicit an anti-GXM response. Sequence analysis of 14 anti-P601E mAbs indicates that anti-P601E mAbs elicited in BALB/c mice have an order of homology with 2H1 of V kappa | J kappa || V(H) | J(H) | D. Further screening of a peptide library with anti-P601E mAbs isolated peptides having a motif almost identical to the peptide motif selected by 2H1. When these
A polysaccharide capsule is one of the most important virulence factors for the pathogenic fungus Cryptococcus neoformans. We previously characterized two capsule-associated genes,CAP59 and CAP64. To further dissect the molecular mechanism of capsule synthesis, 16 acapsular mutants induced by 4-nitroquinoline-1-oxide were obtained. The acapsular phenotype of one of these mutants was complemented. The cloned gene was designatedCAP60, and deletion of this newly described capsule-associated gene resulted in an acapsular phenotype. The proposed 67-kDa Cap60p contains 592 amino acids and appears to have a putative transmembrane domain close to the N terminus. DNA sequence analysis revealed that CAP60 has similarity toCAP59 at the center portion of its coding regions. Contour-clamped homogeneous electric field blot analysis suggested that these two genes are on the same chromosome. CAP60 andCAP59, however, could not be functionally substituted for each other by direct complementation or by domain swap ...
TY - JOUR. T1 - Invasion of the central nervous system by Cryptococcus neoformans requires a secreted fungal metalloprotease. AU - Vu, Kiem. AU - Tham, Rick. AU - Uhrig, John P.. AU - Thompson, George R.. AU - Na Pombejra, Sarisa. AU - Jamklang, Mantana. AU - Bautos, Jennifer M.. AU - Gelli, Angie. PY - 2014/6/3. Y1 - 2014/6/3. N2 - Cryptococcus spp. cause life-threatening fungal infection of the central nervous system (CNS), predominantly in patients with a compromised immune system. Why Cryptococcus neoformans has this remarkable tropism for the CNS is not clear. Recent research on cerebral pathogenesis of C. neoformans revealed a predominantly transcellular migration of cryptococci across the brain endothelium; however, the identities of key fungal virulence factors that function specifically to invade the CNS remain unresolved. Here we found that a novel, secreted metalloprotease (Mpr1) that we identified in the extracellular proteome of C. neoformans (CnMpr1) is required for establishing ...
Background Cryptococcus neoformans is a pathogenic yeast that causes cryptococcosis, a life threatening disease. The prevalence of cryptococcosis in Asia has been rising after the onset of the AIDS epidemic and estimates indicate more than 120 cases per 1,000 HIV-infected individuals per year. Almost all cryptococcal disease cases in both immunocompromised and immunocompetent patients in Asia are caused by C. neoformans var. grubii. Epidemiological studies on C. neoformans in pan-Asia have not been reported. The present work studies the genetic diversity of the fungus by microsatellite typing and susceptibility analysis of approximately 500 isolates from seven Asian countries. Methodology/Principal Findings Genetic diversity of Asian isolates of C. neoformans was determined using microsatellite analysis with nine microsatellite markers. The analysis revealed eight microsatellite complexes (MCs) which showed different distributions among geographically defined populations. A correlation between MCs and
Our studies define the elements of a signal transduction cascade that controls the production of virulence factors and pathogenicity ofC. neoformans. The Pka1 catalytic subunit of PKA regulates mating, melanin and capsule production, and virulence. The Pkr1 regulatory subunit of PKA is also a critical component, and mutants lacking Pkr1 overproduced capsule and were hypervirulent by several measures in two different animal models. pkr1 mutant cells also produced dramatically enlarged capsules during infection, and both the larger capsule size and the increased release of immunosuppressive capsular polysaccharides likely contribute to enhanced virulence.. Epistasis analysis further supports the conclusion that the Gα protein Gpa1 is an upstream controlling element for this signaling pathway and that the Ste12α transcription factor may represent one of several downstream targets of PKA that regulate differentiation and virulence. One interesting finding is that mutants with defects in an ...
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Unique clinical characteristics and other variables influencing the outcome of Cryptococcus neoformans infection in organ transplant recipients have not been well defined. From a review of published reports, we found that C. neoformans infection was documented in 2.8% of organ transplant recipients (overall death rate 42%). The type of primary immunosuppressive agent used in transplantation influenced the predominant clinical manifestation of cryptococcosis. Patients receiving tacrolimus were significantly less likely to have central nervous system involvement (78% versus 11%, p =0.001) and more likely to have skin, soft-tissue, and osteoarticular involvement (66% versus 21%, p = 0.006) than patients receiving nontacrolimus-based immunosuppression. Renal failure at admission was the only independently significant predictor of death in these patients (odds ratio 16.4, 95% CI 1.9 - 143, p = 0.004). Hypotheses based on these data may elucidate the pathogenesis and may ultimately guide the management of C.
Innate immunity plays an important role for fungal recognition and initiation of fungicidal activity. We hypothesize that subtle differences in different molecules of innate immunity may contribute to either the predisposition or clinical course of infection with Cryptococcus neoformans. To test this hypothesis, we propose to analyze the allelic frequencies of 15 different genes (mannose binding lectin, Fc-gamma receptor IIa and IIb, Fc-gamma receptors IIIa and IIIb, myeloperoxidase, tumor necrosis factor-alpha and -beta, interleukin 1A and 1B, interleukin-1 receptor antagonist, interleukin-10, NRAMP-1, chitotriosidase, and chemokine receptor 5) and their intragenic polymorphic forms and to compare this data to the incidence and severity of C neoformans infection. With this study we hope to identify a group of molecules of innate immunity which influence the risk and severity of invasive C neoformans infection ...
Innate immunity plays an important role for fungal recognition and initiation of fungicidal activity. We hypothesize that subtle differences in different molecules of innate immunity may contribute to either the predisposition or clinical course of infection with Cryptococcus neoformans. To test this hypothesis, we propose to analyze the allelic frequencies of 15 different genes (mannose binding lectin, Fc-gamma receptor IIa and IIb, Fc-gamma receptors IIIa and IIIb, myeloperoxidase, tumor necrosis factor-alpha and -beta, interleukin 1A and 1B, interleukin-1 receptor antagonist, interleukin-10, NRAMP-1, chitotriosidase, and chemokine receptor 5) and their intragenic polymorphic forms and to compare this data to the incidence and severity of C neoformans infection. With this study we hope to identify a group of molecules of innate immunity which influence the risk and severity of invasive C neoformans infection ...
TY - JOUR. T1 - Sre1p, a regulator of oxygen sensing and sterol homeostasis, is required for virulence in Cryptococcus neoformans. AU - Chang, Yun C.. AU - Bien, Clara M.. AU - Lee, Hyeseung. AU - Espenshade, Peter J.. AU - Kwon-Chung, Kyung J.. PY - 2007/5/1. Y1 - 2007/5/1. N2 - Cryptococcus neoformans is an environmental pathogen requiring atmospheric levels of oxygen for optimal growth. Upon inhalation, C. neoformans disseminates to the brain and causes meningoencephalitis, but the mechanisms by which the pathogen adapts to the low-oxygen environment in the brain have not been investigated. We found that SRE1, a homologue of the mammalian sterol regulatory element-binding protein (SREBP), functions in an oxygen-sensing pathway. Low oxygen decreased sterol synthesis in C. neoformans and triggered activation of membrane-bound Sre1p by the cleavage-activating protein, Scp1p. Microarray and Northern blot analysis demonstrated that under low oxygen, Sre1p activates genes required for ergosterol ...
Cryptococcus neoformans is a human-pathogenic fungus that has evolved into three distinct varieties that infect most prominently the central nervous system. A sexual cycle involving haploid cells of a and alpha mating types has been reported for two varieties (C. neoformans var. neoformans, serotype …
Infection wif C. neoformans is termed cryptococcosis. Most infections wif C. neoformans occur in de wungs.[12] However, fungaw meningitis and encephawitis, especiawwy as a secondary infection for AIDS patients, are often caused by C. neoformans, making it a particuwarwy dangerous fungus. Infections wif dis fungus are rare in dose wif fuwwy functioning immune systems.[13] So, C. neoformans is sometimes referred to as an opportunistic fungus.[13] It is a facuwtative intracewwuwar padogen[14] dat can utiwize host phagocytes to spread widin de body.[15][16] Cryptococcus neoformans was de first intracewwuwar padogen for which de non-wytic escape process termed vomocytosis was observed.[17][18] It has been specuwated dat dis abiwity to manipuwate host cewws resuwts from environmentaw sewective pressure by amoebae, a hypodesis first proposed by Arturo Casadevaww under de term accidentaw viruwence.[19]. In human infection, C. neoformans is spread by inhawation of aerosowized basidiospores, and can ...
Eukaryota; Fungi; Dikarya; Basidiomycota; Agaricomycotina; Tremellomycetes; Tremellales; Cryptococcaceae; Cryptococcus; Cryptococcus neoformans species ...
Cryptococcus neoformans CAP59 protein: involved in capsule formation which is essential for virulence of Cryptococcus neoformans; amino acid sequence given in first source; GenBank L26508
Antibody-mediated defense against pathogens typically requires complex interactions between antibodies and other constituents of the humoral and cellular immune systems. However, recent evidence indicates that some antibodies alone can inhibit pathogen function in the absence of complement, phagocytes, or NK cells. In this issue of the JCI, McClelland et al. have begun to elucidate the molecular bases by which antibodies alone can impact pathogen growth and metabolism. They show that mAbs specific for the polysaccharide capsule of the human pathogenic fungus Cryptococcus neoformans elicit diverse effects on fungal gene expression, lipid biosynthesis, susceptibility to amphotericin B, cellular metabolism, and protein phosphorylation. These data suggest that pathogens have the capacity to generate broad metabolic responses as a result of surface binding by pathogen-specific antibodies, effects that may hold therapeutic promise. ...
Antibody-mediated defense against pathogens typically requires complex interactions between antibodies and other constituents of the humoral and cellular immune systems. However, recent evidence indicates that some antibodies alone can inhibit pathogen function in the absence of complement, phagocytes, or NK cells. In this issue of the JCI, McClelland et al. have begun to elucidate the molecular bases by which antibodies alone can impact pathogen growth and metabolism. They show that mAbs specific for the polysaccharide capsule of the human pathogenic fungus Cryptococcus neoformans elicit diverse effects on fungal gene expression, lipid biosynthesis, susceptibility to amphotericin B, cellular metabolism, and protein phosphorylation. These data suggest that pathogens have the capacity to generate broad metabolic responses as a result of surface binding by pathogen-specific antibodies, effects that may hold therapeutic promise. ...
TY - CHAP. T1 - Serotypes of Cryptococcus neoformans. AU - Swinne, D. PY - 1981. Y1 - 1981. KW - B780-tropical-medicine. KW - Mycology. KW - Cryptococcus neoformans. KW - Laboratory. KW - Serotypes. M3 - Chapter. SP - 233. EP - 242. BT - Sexuality and pathogenicity of fungi. A2 - Vanbreuseghem, R. A2 - De Vroey, C. PB - Masson. CY - Paris. ER - ...
TY - JOUR. T1 - More information about the natural habitat of Cryptococcus neoformans. AU - Swinne, D. AU - Bauwens, L. AU - Desmet, P. N1 - This item is not available in the ITG Library. PY - 1992. Y1 - 1992. KW - B780-tropical-medicine. KW - Mycology. KW - Cryptococcus neoformans. KW - Natural history. M3 - A2: International peer reviewed article (not A1-type). VL - 60. SP - 4. JO - ISHAM Mycoses Newsletter. JF - ISHAM Mycoses Newsletter. ER - ...
Cryptococcus neoformans causes life-threatening meningoencephalitis in humans, but its overall biological and pathogenic regulatory circuits remain elusive,
Major histocompatibility complex (MHC) genes are unique in their general importance for conferring susceptibility or resistance to infectious and autoimmune diseases (5). It is unclear what keeps these demonstrably harmful genes from being eliminated by natural selection unless they provide some advantage, presumably against some other disease. The only way to unravel these interactions is to characterize the effects of MHC genes on a variety of pathogens and autoimmune diseases. The goal of this study was to experimentally test for an MHC-dependent susceptibility pattern during chronic Cryptococcus neoformans infections.. C. neoformans is a common, opportunistic pathogen that causes disease in immunocompromised individuals. Previous studies have found that various components of immunity are important in clearing a C. neoformans infection. These components include interleukin-12 (11), interleukin-18 (17), inducible nitric oxide synthase (2), gamma interferon (16), B cells (3), and T cells (7). ...
Cryptococcus neoformans (C. neoformans) is a major opportunistic fungal pathogen in individuals with impaired T cell-mediated immunity. Notch pathway is an important signaling component of immunological synapse during APC/T-cell engagement. Little is known about the role of Notch signaling in fungal infections. We sought to determine the role of Notch signaling in C. neoformans infection. Wild-type C57BL/6 (WT) and CD4-Cre+×ROSA DNMAML (DNMAML) mice were infected intratracheally infected with C. neoformans. The fungal burden, leukocyte recruitment, and cytokine profile were assessed at 3 and 6 weeks post-infection (wpi). A 50-fold greater fungal burden was detected in both lungs and brains of DNMAML mice compared to those in the WT mice at 6 wpi. Although, equivalent fungal burdens were found at 3 wpi in WT and DNMAML groups, the production of IFN-γ, IL-4, and IL-13 was significantly decreased in lung leukocytes of DNMAML mice. In contrast, an equivalent induction of IL-17 was observed in both ...
Tumor necrosis factor alpha (TNF-α) plays a critical role in the control of cryptococcal infection, and its insufficiency promotes cryptococcal persistence. To explore the therapeutic potential of TNF-α supplementation as a booster of host anti-cryptococcal responses, we engineered a C. neoformans strain expressing murine TNF-α. Using a murine model of pulmonary cryptococcosis, we demonstrated that TNF-α-producing C. neoformans strain enhances protective elements of host response including preferential T-cell accumulation and improved Th1/Th2 cytokine balance, diminished pulmonary eosinophilia and alternative activation of lung macrophages at the adaptive phase of infection compared to wild type strain-infected mice. Furthermore, TNF-α expression by C. neoformans enhanced the fungicidal activity of macrophages in vitro. Finally, mice infected with the TNF-α-producing C. neoformans strain showed improved fungal control and considerably prolonged survival compared to wild type strain-infected mice,
P. multocida is the causative agent of a wide range of diseases of animals, including fowl cholera in birds. Fowl cholera isolates of P. multocida generally express a capsular polysaccharide composed of hyaluronic acid. There have been reports of spontaneous capsule loss in P. multocida fowl cholera-causing strains but the mechanism by which this occurs has not been determined. In this study, we identified three independent strains that had spontaneously lost the ability to produce capsular polysaccharide. Quantitative RT-PCR showed that these strains had significantly reduced transcription of the capsule biosynthetic genes, but DNA sequence analysis identified no mutations within the cap biosynthetic locus. However, whole genome sequencing of paired capsulated and acapsular strains identified a single nucleotide polymorphism within fis that was present only in the acapsular strain. Sequencing of fis from two independently derived spontaneous acapsular strains showed that each contained a mutation
pathogen-associated molecular patterns (PAMP) are recognized by Toll-like receptors (TLR) and C-type lectin recptors including Dectin-1. Previously, we indicated that neither TLR2 nor TLR4 was involved in the host defence to infection with Cryptococcus neoformans, an opportunistic fungal pathogen in AIDS patients (FEMS Immunol. Med. Microbiol. 47: 148-154, 2006). In the current study, we examined the role of Dectin-1, a receptor for β-glucan, in this response. Dectin-1-deficient mice were resistant to intratracheal and intravenous infection with C. neoformans at a comparable level to wild-type mice. IFN-γ production in lung an serum was not largely different between these mice. There was not significant difference in the synthesis of IL-12p40 and TNF-α by bone marrow-derived dendritic cells upon stimulation with this fungal pathogen. Taken together, these results demonstrated that Dectin-1 did not play a major role in the host protective responses to C. neoformans infection.. This work was ...
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Definition : Molecular assay reagents intended to identify Cryptococcus neoformans, a yeast-like species of imperfect fungi of the family Cryptococcaceae, by detecting specific nucleic-acid information (e.g., DNA, RNA) of the target microorganism. These fungi may cause cryptococcosis, a mycotic infection of the brain and meninges, which may also involve other organs such as the skin and lungs. The disease may progress by invading the central nervous system, lungs, liver, and spleen of immunocompromised patients.. Entry Terms : Cryptococcus Species Detection/Identification Reagents , Cryptococcus neoformans Reagents, Identification , Cryptococcus neoformans Detection/Identification Reagents , Reagents, Cryptococcus neoformans , Reagents, Molecular Assay, Infection, Fungi/Yeast, Cryptococcus neoformans. UMDC code : 19595 ...
Cryptococcus neoformans, a fungal pathogen of humans, causes fatal meningitis in immunocompromised patients. Its virulence is mainly determined by the elaboration of a polysaccharide capsule surrounding its cell wall. During its life, C. neoformans is confronted with and responds to dramatic variations in CO2 concentrations; one important morphological change triggered by the shift from its natural habitat (0.033% CO2) to infected hosts (5% CO2) is the induction of capsule biosynthesis. In cells, CO2 is hydrated to bicarbonate in a spontaneous reaction that is accelerated by carbonic anhydrases. Here we show that C. neoformans contains two beta-class carbonic anhydrases, Can1 and Can2. We further demonstrate that CAN2, but not CAN1, is abundantly expressed and essential for the growth of C. neoformans in its natural environment, where CO2 concentrations are limiting. Structural studies reveal that Can2 forms a homodimer in solution. Our data reveal Can2 to be the main carbonic anhydrase and ...
The population structure of a sample of clinical isolates of C. neoformans serotype A from AIDS patients in Botswana was determined, and the results support hypotheses for both clonal expansion and recombination in this population. Clonal reproduction was previously recognized in C. neoformans, as strains with identical genotypes were isolated from the environment and infected humans (5, 7, 16). The overrepresentation in the population of certain genotypes is a common feature of clonal structure (44). In the sample analyzed here, five genotypes comprised 45% of the total number of isolates (Fig. 4). Another indication of clonality is the calculation of considerable linkage disequilibrium (or nonrandom association) among the loci in the population. The IA and the rd are calculated estimates of linkage disequilibrium (or nonrandom association) among the loci; if there is no association between the loci, these values approach zero, whereas these values are much higher in clonal populations. When ...
Objectives: Cryptococcal meningitis is the third-most-common opportunistic infection in HIV patients in Cambodia. Hospitalized patients were given amphotericin B for initial therapy followed by fluconazole for maintenance therapy. The antifungal drug susceptibility of Cryptococcus neoformans isolated from cerebrospinal fluid (CSF) was determined.. Methods: Isolates of C. neoformans were collected during active laboratory-based surveillance, the first batch from April 2000 to March 2001 (134 new cases), the second batch from April 2001 to March 2002 (268 new cases). Etest strips were used to determine the MICs of amphotericin B and fluconazole. The antigenic agglutination slide test was used for serotyping.. Results: The MIC50s and MIC90s of fluconazole changed significantly from year 2000 to 2002; the MIC50s increased from 4 to 12 mg/L, and the MIC90s from 12 to 96 mg/L. For amphotericin B, the MIC50s and MIC90s remained stable. Moreover, in the second batch, fluconazole MICs were ≥256 mg/L ...
Cryptococcus neoformans is a pathogenic fungus that causes meningitis worldwide, particularly in human immunodeficiency virus (HIV)-infected individuals. Although amphotericin B is the gold standard treatment for cryptococcal meningitis, the toxicity and inconvenience of intravenous injection emphasize a need for development of new anticryptocccal drugs. Recent data from humans and animal studies suggested that a nutrient-deprived host environment may exist in cryptococcal meningitis. Thus, a screening assay for identifying fungicidal compounds under nutrient-deprived conditions may provide an alternative strategy to develop new anticryptococcal drugs for this disease. A high-throughput fungicidal assay was developed using a profluorescent dye, alamarBlue, to detect residual metabolic activity of C. neoformans under nutrient-limiting conditions. Screening the Library of Pharmacologically Active Compounds (LOPAC) with this assay identified a potential chemical scaffold, 10058-F4, that exhibited ...
Pheromones and pheromone receptors have long been known to affect virulence of the opportunistic pathogen Cryptococcus neoformans, yet it is still entirely uncl...
Aritreyee Datta*, Vikas Yadav*, ............, Kaustuv Sanyal, Ayyalusamy Ramamoorthy and Anirban Bhunia, Mode of Action of a Designed Antimicrobial Peptide: High Efficiency in Killing of the Human Fungal Pathogen Cryptococcus neoformans, Biophysical Journal 111, 1724 - 1737 (2016 ...
TY - JOUR. T1 - G protein-coupled receptor Gpr4 senses amino acids and activates the cAMP-PKA pathway in Cryptococcus neoformans. AU - Xue, Chaoyang. AU - Bahn, Yong Sun. AU - Cox, Gary M.. AU - Heitman, Joseph. PY - 2006/2/1. Y1 - 2006/2/1. N2 - The Gα protein Gpa1 governs the cAMP-PKA signaling pathway and plays a central role in virulence and differentiation in the human fungal pathogen Cryptococcus neoformans, but the signals and receptors that trigger this pathway were unknown. We identified seven putative proteins that share identity with known G protein-coupled receptors (GPCRs). One protein, Gpr4, shares limited sequence identity with the Dictyostelium discoideum cAMP receptor cAR1 and the Aspergillus nidulans GPCR protein GprH and also shares structural similarity with the Saccharomyces cerevisiae receptor Gpr1. gpr4 mutants exhibited reduced capsule production and mating defects, similar to gpa1 mutants, and exogenous cAMP suppressed both gpr4 mutant phenotypes. Epistasis analysis ...
Environmental isolations have established that Cryptococcus neoformans var. gattii appears to have a specific ecological association with Eucalyptus camaldulensis. So far, we have isolated C. neoformans var. gattii on 35 separate occasions, all from samples associated with E. camaldulensis. The global distribution of E. camaldulensis appears to correspond to the epidemiologic distribution of cryptococcosis caused by C. neoformans var. gattii. No other environmental source for the fungus has yet been detected, and no other eucalypt has the distribution pattern corresponding to reported cases caused by this fungus. These findings may provided an explanation for the high incidence of infections caused by C. neoformans var. gattii in Australian aborigines living in the Northern Territory and for its low worldwide incidence in acquired immunodeficiency syndrome patients. ...
INTRODUÇÃO. A criptococose é uma importante infecção oportunista, principalmente devido ao aumento do número de indivíduos imunocomprometidos, em especial aqueles infectados com HIV1,2. As espécies implicadas em grande parte dos casos são Cryptococcus neoformans e Cryptococcus gattii, causadoras de variadas formas clínicas da doença3,4,5. Neste contexto, indivíduos imunocompetentes podem adquirir a doença como micose primária, principalmente devido a C. gattii, em regiões tropicais e subtropicais6, bem como sob a forma de surtos7. Cryptococcus spp. são leveduras basidiomicetos, capsuladas, sapróbias do ambiente, sendo isoladas principalmente de excretas de aves e ocos de árvores, como por exemplo, eucalipto8 e Senna sp.9. C. neoformans é constituído pelos sorotipos A (tipos moleculares VNI, VNII), D (tipo molecular VNIV) e o híbrido AD (tipo molecular VNIII); C. gattii inclui o sorotipo B (tipos moleculares VGI, VGII, VGIII, VGIV) e o sorotipo C10,11,12.. Em Belém, Estado ...
TY - JOUR. T1 - Mapping of the Cryptococcus neoformans MATα locus. T2 - Presence of mating type-specific mitogen-activated protein kinase cascade homologs. AU - Karos, M.. AU - Chang, Y. C.. AU - McClelland, C. M.. AU - Clarke, D. L.. AU - Fu, J.. AU - Wickes, B. L.. AU - Kwon-Chung, K. J.. N1 - Copyright: Copyright 2007 Elsevier B.V., All rights reserved.. PY - 2000. Y1 - 2000. N2 - In this study we investigated the relationship between the MATα locus of Cryptococcus neoformans and several MATα-specific mitogen-activated protein (MAP) kinase signal transduction cascade genes, including STE12α, STE11α, and STE20α. To resolve the location of the genes, we screened a cosmid library of the MATα strain B-4500 (JEC21), which was chosen for the C. neoformans genome project. We isolated several overlapping cosmids spanning a region of about 71 kb covering the entire MATα locus. It was found that STE12α, STE11α, and STE20α are imbedded within the locus rather than closely linked to the locus. ...
Cryptococcosis, also known as cryptococcal disease is a potentially fatal fungal disease. It is caused by inhalation of an encapsulated yeast called Cryptococcus neoformans. Cryptococcosis is believed to be acquired by inhalation of the infectious propagule from the environment. Although the exact nature of the infectious propagule is unknown, the leading hypothesis is the basidiospore created through sexual or asexual reproduction.. Cryptococcosis market: Types of infection. There are three identified Cryptococcus strains that causes disease worldwide namely Cryptococcus neoformans, Cryptococcus grubii and Cryptococcus gattii. Exposure via respiratory or the gastrointestinal tract are considered as the most common and opportunistic pathway for the organism entry in the host. Cryptococcus neoformans can be found worldwide in soil, birds, animals and humans. Whereas, alternative route of administration can be through transplant of infected tissue, surgical instrument or laboratory instruments. ...
The following thesis is a composite of two separate research projects which were undertaken by the author for the award of an MRes in Molecular and Cellular Biology within the School of Biosciences at the University of Birmingham. Part one of this thesis will detail the first research project which sought to characterise the contribution of the enzyme phospholipase B to the intercellular lifecycle employed by the pathogenic fungus Cryptococcus neoformans which has the ability to survive within the phagolysosome of immune cell macrophages. This project used cell culture and microscopy techniques as well as whole cell lipidomic analysis and found that many aspects of Cryptococcus neoformans parasitism of macrophages are modified by phospholipase B activity. Part two of this details the second project which examined the predatory bacteria Bdellovibrio bacteriovorous. This bacterium has a unique lifecycle which involves predation of other gram negative bacteria resulting in prey cell invasion and an ...
To assess the relationship between melanin production by Cryptococcus neoformans and virulence on a molecular basis, we asked: (a) is CNLAC1, the laccase structural gene of C. neoformans, expressed in vivo?; (b) can mouse virulence be restored to cnlac1 (Mel-) mutants by complementation with CNLAC1?; and (c) will targeted gene deletion of CNLAC1 decrease virulence for mice? Melanin is produced when cryptococcal laccase catalyzes the oxidation of certain aromatic compounds, including L-dopa, to quinones, which then polymerize to melanin. To assess CNLAC1 transcription, RNA was extracted from C. neoformans in cerebrospinal fluid of infected rabbits. Reverse transcriptase-polymerase chain reaction detected CNLAC1 transcript, indicating that laccase may be produced in the infected host. To assess the effect of CNLAC1 deletion on virulence, a Mel- mutant (10S) was obtained by disruption of the 5 end of the gene. After multiple backcrosses with a parental strain to remove unintended genetic defects ...
0141] FIGS. 5A to 5E are bar charts showing the viability of Gram-positive bacteria Bacillus subtilis, Staphylococcus aureus, methicillin-resistant Staphylococcus aureus and Enterococcus faecalis, and the fungus Cryptococcus neoformans, respectively, when treated with micelles formed from Example 1. FIGS. 6A to 6E are bar charts showing the viability of Gram-positive bacteria Bacillus subtilis, Staphylococcus aureus and methicillin-resistant Staphylococcus aureus, and the fungus Cryptococcus neoformans as well as Gram-positive bacterium Enterococcus faecalis, respectively, when treated with micelles formed from Example 3. FIG. 7 is a bar chart showing the viability of Gram-positive bacteria Bacillus subtilis when treated with micelles formed from Example 2. Example 2 does not show a strong inhibition effect towards bacterial growth, having a MIC of higher than 66.4 micromole/L against Bacillus subtilis (FIG. 7). This is attributed to the polymer with the longest hydrophobic block precipitating ...
Studies indicate that the accuracy of correct identification of the C. gattii strains using d-proline assimilation tests (2, 3, 13, 31) or d-tryptophan assimilation tests (2, 3, 35) was favorable with the CGB (25) method. The assimilation assays are based on the fact that only the C. gattii strains utilized these d-amino acids as the sole nitrogen source. In some studies the accuracy of these tests approaches 99% but the assay was relatively slow because the formulation used low glucose concentrations (1 to 2%). The current study suggests that it is feasible to combine d-tryptophan and d-proline into a single medium to separate C. gattii from C. neoformans. The use of m-DTDP or YCB-DTDP increased the carbohydrate source from 2 to 4%, such that most C. gattii strains achieved growth in 1 to 3 days. The current limitation for growth is the nitrogen source. We suggest using YCB-DTDP agar or m-DTDP agar, since the accuracy is similar to those of previously published methods and test results are ...
Background Cryptococcus neoformans causes life-threatening meningitis. A recently introduced lateral flow immunoassay (LFA) to detect cryptococcal antigen (CRAG) is reportedly more rapid and convenient than standard latex agglutination (LA), but has not yet been evaluated in a diagnostic laboratory setting. Methods One hundred and six serum, 42 cerebrospinal fluid (CSF), and 20 urine samples from 92 patients with known or suspected cryptococcosis were tested by LA and LFA, and titres were compared. Results were correlated with laboratory-confirmed cryptococcosis. Serial samples were tested in nine treated patients. Results Twenty-five of 92 patients had confirmed cryptococcosis; all sera (n = 56) from these patients were positive by LFA (sensitivity 100%, 95% confidence interval (CI) 93.6-100%) compared with 51/56 positive by LA (sensitivity 91.1%, 95% CI 80.7-96.1%). Fifty sera from 67 patients without cryptococcosis tested negative in both assays. While LA yielded more false negative results (5/56
Cryptococcus neoformans, the causative fungal agent of cryptococcosis remain a common cause of infectious morbidity and mortality, especially among HIV-positive patients living in Sub-Saharan Africa and South-East Asia. This study was undertaken to evaluate the prevalence and clinical presentation of Cryptococcus infections among HIV positive and negative patients in RIMS, Manipur. Specimens like CSF, sputum, urine, blood, tissue biopsy or aspirates from clinically suspected cryptococcosis cases from RIMS hospital, were subjected to mycological examination. Out of the 48 patients enrolled for the study, Cryptococcus spp were isolated from 16 (33.33%) patients. Among these 16 cryptococcosis patients, majority of them presented with cryptococcal meningitis 13 (81.25%), while 1 (6.25%) patient each presented with cryptococcal lymphadenitis, disseminated cutaneous cryptococcosis and osseous cryptococcosis respectively. Also, of these 16 cryptococcosis patients, 14 (87.5%) were HIV positive. Among these HIV
TY - JOUR. T1 - Ssk2 mitogen-activated protein kinase kinase kinase governs divergent patterns of the stress-activated Hog1 signaling pathway in Cryptococcus neoformans. AU - Bahn, Yong Sun. AU - Geunes-Boyer, Scarlett. AU - Heitman, Joseph. PY - 2007/12. Y1 - 2007/12. N2 - The stress-activated p38/Hog1 mitogen-activated protein kinase (MAPK) pathway is structurally conserved in many diverse organisms, including fungi and mammals, and modulates myriad cellular functions. The Hog1 pathway is uniquely specialized to control differentiation and virulence factors in a majority of clinical Cryptococcus neoformans serotype A and D strains. Here, we identified and characterized the Ssk2 MAPKKK that functions upstream of the MAPKK Pbs2 and the MAPK Hog1 in C. neoformans. The SSK2 gene was identified as a potential component responsible for the difference in Hog1 phosphorylation between the serotype D f1 sibling strains B-3501 and B-3502 through comparative analysis of meiotic maps showing their meiotic ...
Cryptococcosis, also known as cryptococcal disease, is a potentially fatal fungal disease. It is caused by one of two species; Cryptococcus neoformans and Cryptococcus gattii. These were all previously thought to be subspecies of C. neoformans but have now been identified as distinct species. Cryptococcosis is believed to be acquired by inhalation of the infectious propagule from the environment. Although the exact nature of the infectious propagule is unknown, the leading hypothesis is the basidiospore created through sexual or asexual reproduction. Cryptococcosis is a defining opportunistic infection for AIDS, and is the second-most-common AIDS-defining illness in Africa. Other conditions that pose an increased risk include certain lymphomas (e.g., Hodgkins lymphoma), sarcoidosis, liver cirrhosis, and patients on long-term corticosteroid therapy. Distribution is worldwide in soil. The prevalence of cryptococcosis has been increasing over the past 20 years for many reasons, including the ...
Looking for Cryptococcus? Find out information about Cryptococcus. A genus of encapsulated pathogenic yeasts in the order Moniliales Explanation of Cryptococcus
Cryptococcosis is an opportunistic yeast infection caused by Cryptococcus neoformans that remains the most common systemic fungal infection in immunosuppressed patients and often presents with signs of meningitis. Primary cutaneous cryptococcosis (PCC) is a more rare clinical identity that is characterized by skin lesions confined to 1 body region, often presenting as a whitlow or phlegmon with positive culture for C neoformans and no evidence of simultaneous dissemination. We report a rare case of PCC in a 73-year-old man with intact cell-mediated immunity. Read More ...
The study of fungal regulatory networks is essential to the understanding of how these pathogens respond to host environmental signals with effective virulence-associated traits. In this study, a virulence-associated DEAD-box RNA helicase-encoding gene (VAD1) was isolated from a mutant defective in the virulence factor laccase. A Deltavad1 mutant exhibited a profound reduction in virulence in a mouse model that was restored after reconstitution with WT VAD1. Loss of VAD1 resulted in upregulation of NOT1, a gene encoding a global repressor of transcription. NOT1 was found to act as an intermediary transcriptional repressor of laccase. Vad1 was located within macromolecular complexes that formed cytoplasmic granular bodies in mature cells and during infection of mouse brain. in addition, VAD1 was shown by in situ hybridization to be expressed in the brain of an AIDS patient coinfected with C. neoformans. To understand the role of VAD1 in virulence, a functional genomics approach was used to ...
Hughes, William S. (2015) Cryptococcus neoformans phospholipase B and its influence on fungal cell morphology AND A study into proteins proposed to be involved in C-di-GMP signalling and predation from Bdellovibrio bacteriovorus - Bd1483, Bd1996, Bd2538 and Bd3100. M.Res. thesis, University of Birmingham.. Evans, Robert J. (2013) How does the expression of phospholipase B influence the host pathogen relationship between Cryptococcus neoformans and the macrophage? and An investigation into the properties of two Bdellovibrio bacteriovorus C-di-GMP metabolism proteins - Bd2325 and Bd1971. M.Res. thesis, University of Birmingham.. Ma, Hansong (2009) Intracellular parasitism of macrophages by Cryptococcus. Ph.D. thesis, University of Birmingham.. Smith, Leanne May (2015) Investigating phagosome dynamics of microbial pathogens. Ph.D. thesis, University of Birmingham.. Gilbert, Andrew Stephen (2017) Investigating the molecular mechanisms of vomocytosis. Ph.D. thesis, University of Birmingham.. Needs, ...
Results: 57 patients were studied. Cryptococcus neoformans var grubii molecular type VN1 caused 70% of infections; C. gattii accounted for the rest. Most patients did not have underlying disease (81%), and the rate of underlying disease did not differ by infecting species. 11 patients died while in-patients (19.3%). Independent predictors of death were age ≥ 60 years and a history of convulsions (odds ratios and 95% confidence intervals 8.7 (1 - 76), and 16.1 (1.6 - 161) respectively). Residual visual impairment was common, affecting 25 of 46 survivors (54.3%). Infecting species did ...
The study of regulatory networks in human pathogens such as Cryptococcus neoformans provides insights into host-pathogen interactions that may allow for correlation of gene expression patterns with clinical outcomes. In the present study, deletion of the cryptococcal copper-dependent transcription factor 1 (Cuf1) led to defects in growth and virulence factor expression in low copper conditions. In mouse models, cuf1Δ strains exhibited reduced dissemination to the brain, but no change in lung growth, suggesting copper is limiting in neurologic infections. To examine this further, a biologic probe of available copper was constructed using the cryptococcal CUF1-dependent copper transporter, CTR4. Fungal cells demonstrated high CTR4 expression levels after phagocytosis by macrophage-like J774.16 cells and during infection of mouse brains, but not lungs, consistent with limited copper availability during neurologic infection. This was extended to human brain infections by demonstrating CTR4 ...
The risk of developing fungal meningitis from Cryptococcus neoformans rises dramatically when people have weakened immunity, due to HIV infection or other reasons including the use of immunosuppressive drugs after organ transplantation, or for treating autoimmune diseases or cancer. Knowing which patients are most likely to develop fungal meningitis would allow costly drugs for preventing fungal disease to be targeted to those most in need. (In the U.S., the widespread use of antiretroviral therapy by HIV-infected people, and their preventive use of anti-fungal drugs, has dramatically reduced their rate of fungal meningitis from Cryptococcus neoformans to about 2 ...
A large number of molecular typing techniques have been applied over the years to discriminate between individual isolates that had been indistinguishable using conventional techniques and to obtain further insights into the epidemiology and population structure of this species complex. This chapter aims to summarize the diverse typing techniques applied to the Cryptococcus neoformans/C. gattii species complex, to correlate the obtained results, and to describe the global distribution of the major genotypes. The enzymes malate dehydrogenase, alcohol dehydrogenase, phosphoglyceromutase, and glutamate dehydrogenase could separate C. gattii from C. neoformans. Electrophoretic karyotyping was for the first time applied to the C. neoformans/C. gattii species complex to study the genetic diversity between seven cryptococcal strains representing all four serotypes. PCR fingerprinting using the primer (GACA)4 was applied to 110 cryptococcal isolates obtained mainly from Germany and Africa as well as additional
TY - JOUR. T1 - Cryptococcal encephalitis in thermally injured mice is accelerated by type 2 T-cell responses. AU - Furukawa, Katsunori. AU - Kobayashi, Makiko. AU - Sasaki, Hidetaka. AU - Herndon, David. AU - Pollard, Richard B.. AU - Suzuki, Fujio. PY - 2002. Y1 - 2002. N2 - Objective: To explore the pathogenic role of burn-associated type 2 T-cell responses on the development of cryptococcal encephalitis in mice with severe thermal injuries. Design: Experimental Cryptococcus neoformans infection in normal mice was compared with that in thermally injured mice (TI mice), normal mice heated with a mixture of interleukin (IL)-4 and IL-10, or normal mice inoculated with burn-associated type 2 T cells. Setting: University research laboratory. Subjects: Male BALB/c mice, 8 to 10 wks of age. Interventions: We prepared four groups of mice as follows: a) normal mice, b) TI mice, c) normal mice treated with the IL-4/IL-10 mixture, and d) normal mice inoculated with burn-associated type 2 T cells. These ...
A less likely alternative hypothesis is that calcineurin is not part of a signal transduction pathway required for virulence, but is instead required to maintain activity of components required for growth at high temperature and CO2 and pH resistance. Such a model would require that some proteins differ in phosphorylation state at 37 and 24°C, or that activity at 37°C requires dephosphorylation whereas activity at 24°C does not. One means to test these and other models, and to identify downstream effectors of calcineurin, would be to characterize suppressor mutations that restore growth to calcineurin mutants at 37°C. In summary, our studies reveal that calcineurin is required for virulence and may delineate the first elements of a signal transduction cascade required for fungal pathogenesis.. By analogy with other systems, the targets of calcineurin might include ion pumps or transcription factors, which could regulate expression of other proteins required for virulence. The role of ...
One of the more interesting aspects of C. neoformans interactions with the host is the large discrepancy in the incidence of infections in male and female patients, with males having a higher incidence of C. neoformans infection and disease than females. This gender-related difference has been observed in dozens of studies and suggests underlying differences in the interactions of the immune response to C. neoformans infection and differential expression of microbial factors between males and females. We have found differences in the immune response of ex vivo male or female macrophages to C. neoformans, PLoS One, 2013. Currently, we are characterizing gender-specific and microbial factors in clinical isolates to determine which factors are involved in the gender susceptibility difference to C. neoformans.. 2. Determine how C. neoformans modulates cell signaling in macrophages Another key aspect of the C. neoformans host-pathogen interaction is with host macrophages. I am collaborating with Dr. ...
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TY - JOUR. T1 - Activation of macrophages and expansion of specific T lymphocytes in the lungs of mice intratracheally inoculated with Cryptococcus neoformans. AU - Kawakami, K.. AU - Kohno, S.. AU - Morikawa, N.. AU - Kadota, J.. AU - Saito, A.. AU - Hara, K.. N1 - Copyright: Copyright 2020 Elsevier B.V., All rights reserved.. PY - 1994. Y1 - 1994. N2 - A quantitative and qualitative change in inflammatory cells in the lungs of mice after intratracheal inoculation of heat-killed Cryptococcus neoformans was examined by direct analysis of the pulmonary intraparenchymal leucocytes. Macrophages and T and B lymphocytes increased, peaked at day 7, and then gradually decreased to the basal level. Macrophages were activated 7 days after the inoculation, as indicated by the enhanced expression of MHC class II, intercellular adhesion molecule-1 (ICAM-1) and Fc receptor (FcR), which have been known as their activation markers. T cells were also activated, as indicated by the induction of IL-2 receptor ...
Results: Showed that the yeast was grow with typical colonies on the new medium compared with other media which using in diagnosed of this yeast such as Staib agar and Sabourauds dextrose agar and unlike the yeast Candida albicans (as a negative control), which appeared in cream to white on this medium. Furthermore, the colonies are dark brown in color on flower chrysanthemum medium and light brown color on leaves chrysanthemum medium. In addition, the results of the chemical and spectral tests of the extracts confirmed that the plant contains many active compounds such as alkaloids, turbines, tannins, and phenols. The analysis of the extracts of phenolic compounds using GC-mass led to the diagnosis of five compounds in the leaf extract and nine compounds in the flower extract of this plant. ...
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Cryptococcus is a polyphyletic genus that is present in all five major lineages of the Tremellomycetes (Agaricomycotina). Cryptococcus wieringae (syn=Filobasidium wieringae) was described by Fonseca et al. (2000) to re-classify strains of Cryptoccocus albidus related to Cryptoccocus magnus. Like many other members of Filobasidiales, Cryptococcus wieringae is also found in association with plants. The original identification by Wieringa (1956) was on samples isolated from flax straw when a role in pectin hydrolysis during the dew-retting process of flax was suggested. It has also been isolated from soil samples (Arenz et al. 2006) and glaciers (Branda et al. 2010).. This genome was sequenced as part of the 1000 fungal genomes project ...
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A study on the identification of hybrids identified six distinct clusters based on the genotypes of a large number of Cryptococcus neoformans and Cryptococcus gattii global isolates using amplified fragment length polymorphism (AFLP). A combination of genotype and ploidy analyses are able to discriminate AD hybrids from haploid serotype A or D isolates. Serological reactions and a set of genotyping techniques have been used to determine the serotype of Cryptococcus strains. Serotype A strains presented a rim pattern characterized by a sharp increase in the optical gradient at the capsular edge followed directly by an immediate decrease. The estimation of the time of hybridization showed that recombination occurred very recently, indicating that hybridization is important during Cryptococcus evolution. Gene genealogical analysis supported the hypothesis of multiple origins of hybrid strains, suggesting that hybridization events occurred in different times probably coinciding with the continuing
Recently, membrane vesicle (MV) production was described in Gram-positive bacteria, which harbor a variety of components such as toxins, antibiotic resistance proteins, proteases, DNA, and immune modulators. Free lipids have the ability to form micelles, thus it is important to rule out spontaneous association of lipids into vesicle-like structures and rather, that MVs are produced naturally by a metabolically active cell. Here, we describe a protocol utilizing the polysaccharide, glucuronoxylomannan (GXM) from Cryptococcus neoformans (C. neoformans) as a marker to differentiate naturally produced MVs from vesicles that form spontaneously in the Gram-positive model organism, Bacillus subtilis (B. subtilis). MVs are purified from bacterial cultures grown in the presence of GXM; MVs naturally produced by cells would not contain GXM in the lumen whereas vesicular structures forming in the media could encapsulate GXM and this can be visualized via immunogold transmission electron microscopy.
Cryptococcosis is a fungal infection caused specifically by the fungus cryptococcus neofromans, which is usually found in soil and bird droppings or less commonly, the fungus cryptococcus gatti, found in sub-tropical regions. An individual usually contracts this infection through the air by breathing in the spores. Cryptococcocsis is most commonly associated with HIV and with people with weakened immune systems such as Hodgkins disease, individuals taking high doses of corticosteroid medications or undergoing chemotherapy. However, cryptococcocsis may affect individuals with normal immune systems as well. In some cases, there are no symptoms at all, however because the fungus is typically inhaled, the lungs are most commonly infected. It is more likely to spread beyond the lungs to the brain (and cause meningitis) in individuals with weakened immune systems. Symptoms may include blurred vision, chest pain, fatigue, dry coughs, fever, headache, nausea, sweating, and skin rashes. Other symptoms ...
A team of US researchers has discovered that three different species of Klebsiella bacteria can cause life-threatening infections in hospital patients and that all three share genes that confer resistance to the most commonly used antibiotics. The study, published this week in mSphere®, an open-access journal of the American Society for Microbiology, improves physicians understanding of Klebsiella infections and could point toward better ways to fight multi-drug resistant strains of these bacteria.
Filobasidiella neoformans ATCC ® 34873™ Designation: NIH B-3501 [CBS 6900, CBS 7697, CBS 7817, CCRC 20532] Application: Biomedical Research and Development Material assay of eumelanin pigments ref   ref produces monophenol monooxygenase phenol oxidase, phenoloxidase ref regulation of phenol oxidase and capsular polysaccharide ref
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Casadevall is Professor and Chair of the Department of Microbiology and Immunology at Albert Einstein College of Medicine of Yeshiva University in New York. His research centers on the questions of how microbes cause disease and how hosts, such as humans, defend themselves. To explore this dynamic relationship, Casadevall and colleagues have long examined Cryptococcus neoformans, a common fungus that is harmless to healthy people but can cause serious disease, including lung infections and fungal meningitis, in immune-compromised people such as those with HIV/AIDS. Many of the laboratorys projects seek to understand how hosts defend against C. neoformans and how the organisms virulence contributes to disease ...
Beale, MA; Robertson, E; Simwami, SP; Fuentes, K; Jarvis, JN; Loyse, A; Bradley, J; Meintjes, GA; Wilson, D; Harrison, TS; +2 more... Fisher, MC; Bicanic, T; (2014) Cryptococcus neoformans molecular type VNB is associated with mortality in HIV associated cryptococcal meningitis in South Africa. [Conference or Workshop Item] https://researchonline.lshtm.ac.uk/id/eprint/1805361 ...
A postdoctoral position is available to study mechanisms by which pathogenic fungi (eg, Candida albicans and Cryptococcus neoformans) regulate intracellular acyclic polyols concentrations. Acyclic polyols such as D-arabinitol and mannitol function in fungi as intracellular osmolytes and as oxidative stress protectants, and mutants with diminished abilities to synthesize and accumulate acyclic polyols are stress-intolerant and hypovirulent (Microbiol 1996;142:937; J Immunol 1996;156:3836; J Bacteriol 1997;179:157). Our past studies have focused on the metabolic pathways by which C. albicans and C. neoformans synthesize and catabolize polyols and the functional and pathogenic significance of these pathways (J Bacteriol 1993;175:6314 and 1995;177:2971). The new postdoctoral associate will study the mechanisms by which pathogenic fungi maintain and regulate high acyclic polyol concentration gradients across the cell membrane. One possible approach will be (i) to clone the cDNAs and/or genes encoding ...
Cryptococcus neoformans is an encapsulated yeast. In 1894, Busse, a pathologist, first described the yeast in a paper he presented to the Greifswald Medical Society.
An acute or chronic, localized or disseminated infection by cryptococcus neoformans. Sites of involvement include the lungs, central nervous system and meninges, skin, and visceral organs ...
The in vitro and in vivo toxicities and activities of MS-8209, a new hydrosoluble amphotericin B (deoxycholate-amphotericin B [D-AmB]; Fungizone) derivative, were studied. In vitro, MS-8209 was less toxic than AmB against renal tubular cells in primary culture and less active against Candida albicans and Cryptococcus neoformans. However, at 10-fold the AmB concentration, MS-8209 in vitro antifungal activity paralleled that of AmB. Fifty-percent lethal doses of MS-8209 and D-AmB in OF1 noninfected mice were 26 and 2.3 mg/kg, respectively. Therapeutic efficacy of MS-8209 was assessed in murine candidiasis, cryptococcosis, and aspergillosis. In each model of infection, we determined the maximum tolerated dosages of MS-8209 and D-AmB, i.e., the dosage inducing less than 15% mortality due to toxicity; the efficacies of MS-8209 and D-AmB at their respective maximum tolerated dosages were compared. In candidiasis, MS-8209 (15 mg/kg) significantly increased the survival time compared with D-AmB (0.5 ...