Mycelial Phase Research Articles

Comparative proteomics of sugarcane smut fungus - Sporisorium scitamineum unravels dynamic proteomic alterations during the dimorphic transition

Life cycle of the dimorphic sugarcane smut fungi, Sporisorium scitamineum, involves recognition and mating of compatible saprophytic yeast-like haploid sporidia (MAT-1 and MAT-2) that upon fusion, develop into infective dikaryotic mycelia. Although the dimorphic transition is intrinsically linked with the pathogenicity and virulence of S. scitamineum, it has never been studied using a proteomic approach. In the present study, an iTRAQ-based comparative proteomic analysis of three distinct stages was carried out. The stages were: the dimorphic transition period - haploid sporidial stage (MAT-1 and MAT-2); the transition phase (24 h post co-culturing (hpc)) and the dikaryotic mycelial stage (48 hpc). Functional categorization of differentially abundant proteins showed that the most altered biological processes were energy production, primary metabolism, especially, carbohydrate, amino acid, fatty acid, followed by translation, post-translation and protein turnover. Several differentially abundant proteins (DAPs), especially in the dikaryotic mycelial stage were predicted as effectors. Taken together, key molecular mechanisms underpinning the dimorphic transition in S. scitamineum at the proteome level were highlighted. The catalogue of stage-specific and dimorphic transition-associated-proteins and potential effectors identified herein represents a list of potential candidates for defective mutant screening to elucidate their functional role in the dimorphic transition and pathogenicity in S. scitamineum. Biological significanceBeing the first comparative proteomics analysis of S. scitamineum, this study comprehensively examined three pivotal life cycle stages of the pathogen: the non-pathogenic haploid phase, the transition phase, and the pathogenic dikaryotic mycelial stage. While previous studies have reported the sugarcane and S. scitamineum interactions, this study endeavored to specifically identify the proteins responsible for pathogenicity. By analyzing the proteomic alterations between the haploid and dikaryotic mycelial phases, the study revealed significant changes in metabolic pathway-associated proteins linked to energy production, notably oxidative phosphorylation, and the citrate cycle. Furthermore, this study successfully identified key metabolic pathways that undergo reprogramming during the transition from the non-pathogenic to the pathogenic stage. The study also deciphered the underlying mechanisms driving the morphological and physiological alterations crucial for the S. scitamineum virulence. By studying its life cycle stages, identifying the key metabolic pathways and stage-specific proteins, it provides unprecedented insights into the pathogenicity and potential avenues for intervention. As proteomics continues to advance, such studies pave the way for a deeper understanding of plant-pathogen interactions and the development of innovative strategies to mitigate the impact of devastating pathogens like S. scitamineum.

Fabrication of Living Entangled Network Composites Enabled by Mycelium.

Organic polymer-based composite materials with favorable mechanical performance and functionalities are keystones to various modern industries; however, the environmental pollution stemming from their processing poses a great challenge. In this study, by finding an autonomous phase separating ability of fungal mycelium, a new material fabrication approach is introduced that leverages such biological metabolism-driven, mycelial growth-induced phase separation to bypass high-energy cost and labor-intensive synthetic methods. The resulting self-regenerative composites, featuring an entangled network structure of mycelium and assembled organic polymers, exhibit remarkable self-healing properties, being capable of reversing complete separation and restoring ≈90% of the original strength. These composites further show exceptional mechanical strength, with a high specific strength of 8.15MPag.cm-3, and low water absorption properties (≈33% after 15 days of immersion). This approach spearheads the development of state-of-the-art living composites, which directly utilize bioactive materials to "self-grow" into materials endowed with exceptional mechanical and functional properties.

Growth inhibitory effect of selected medicinal plants from Southern Ethiopia on the mycelial phase of Histoplasma capsulatum var. farciminosum

BackgroundEpizootic lymphangitis is an infectious and chronically debilitating disease of the equines. Histoplasma capsulatum var. farciminosum, a thermally dimorphic fungi, is the causative agent for the disease. In Ethiopia, the disease significantly affects carthorses, posing threats to animal welfare, and resulting in substantial economic losses. Limited availability of widely accessible antifungals in addition to the chronic nature of the disease is the major challenge against management of epizootic lymphangitis. This study aimed to assess the in vitro efficacy of specific local medicinal plant extracts against the mycelial phase development of H. capsulatum var. farciminosum in southern Ethiopia. The leaves of Xanthium strumarium, Kanda (Family Rubiaceae), Croton macrostachyus (Bisana in Amharic), and Centella Asiatica (Echere waye as a local name in Zeyissegna) that are traditionally used for the treatment of different skin ailments were collected and extracted for the in vitro trial.ResultsThe study revealed that methanol extracts of Xanthium strumarium, Kanda, Croton macrostachyus, and Centella Asiatica, at minimum inhibitory concentrations of 1.25 mg/ml, 2.5 mg/ml, 2.5 mg/ml, and 5 mg/ml, respectively, inhibited the growth of H. capsulatum var. farciminosum.ConclusionThis in vitro finding could serve as significant preliminary data in the exploration of effective alternative treatment options for epizootic lymphangitis. This study provides a crucial foundation for further research aimed at determining the chemical components and in vivo effectiveness of these plant extracts against both the mycelial and yeast forms of Histoplasma capsulatum var. farciminosum.

Molecular detection of Histoplasma capsulatum in organ samples from bats randomly captured in urban areas of Araraquara, São Paulo state, Brazil.

The mycosis histoplasmosis is also considered a zoonosis that affects humans and other mammalian species worldwide. Among the wild mammals predisposed to be infected with the etiologic agent of histoplasmosis, bats are relevant because they are reservoir of Histoplasma species, and they play a fundamental role in maintaining and spreading fungal propagules in the environments since the infective mycelial phase of Histoplasma grows in their accumulated guano. In this study, we detected the fungal presence in organ samples of bats randomly captured in urban areas of Araraquara City, São Paulo, Brazil. Fungal detection was performed using a nested polymerase chain reaction to amplify a molecular marker (Hcp100) unique to H. capsulatum, which revealed the pathogen presence in organ samples from 15 out of 37 captured bats, indicating 40.5% of infection. Out of 22 Hcp100-amplicons generated, 41% corresponded to lung and trachea samples and 59% to spleen, liver, and kidney samples. Data from these last three organs suggest that bats develop disseminated infections. Considering that infected bats create environments with a high risk of infection, it is important to register the percentage of infected bats living in urban areas to avoid risks of infection to humans, domestic animals, and wildlife.

Effectiveness of various nematode-trapping fungi for biocontrol of the Meloidogyne incognita in tomato (Lycopersicion esculentum Mill.)

The nine promising species of nematode-trapping fungi namely Dr. dactyloides, Dr. brochopaga, Da. gephyropaga, Da. phymatopaga, A. eudermata, A. oligospora, A. conoides, A. thaumasia and A. musiformis were isolated from the root-knots rhizosphere to compare their, in vitro nematode trapping ability against Meloidogyne incognita, ability to form conidial traps close to nematode infested soils and their effectiveness in reducing on M. incognita infection indices on tomato. The laboratory assays of nematophagous efficacy of nine nematode-trapping fungi against M. incognita revealed that Dr. dactyloides, Dr. brochopaga, D. gephyropaga and Da. phymatopaga seemed to be the most effective, with 73.2–99.8% trapping and killing of juveniles within 5 days of nematode and fungal interface. Conidial trap forming ability of different species of nematode-trapping fungi showed that Dr. dactyloides, Dr. brochopaga formed frequent formation of conidial traps without intermediate germ tubes whereas Da. phymatopaga and Da. gephyropaga formed adhesive traps on spore germ tubes in close vicinity of root-knot nematode infested soils and killed the nematode present on the agar discs. A. eudermata, A. oligospora, A. conoides, A. thaumasia and A. musiformis frequently germinated by germ tubes in soil and occasionally formed fewer traps. The pot experiment results showed that Dr. brochopaga and Dr. dactyloides, which dominantly formed conidial traps without an intermediate mycelial phase caused the highest decrease in the number of roots-knots (67.2–70.4%), females (80.5–85.8%) and eggs and juveniles (84.9–88.8%) of M. incognita followed by Da. gephyropaga and Da. phymatopaga which formed traps on conidial germ lings and mycelium. A. eudermata, A. oligospora, A. conoides, A. thaumasia and A. musiformis which formed poor conidial traps caused a moderate decrease in the number of root-knots (45.3–53.4%), females (55.5–61.1%), eggs and juveniles (52.9–60.1%) of M. incognita in comparison to control. This paper analyses the effective biocontrol of M. incognita by using different nematode-trapping fungi, especially conidial traps forming fungi and the fate of application of these species in the RKN-infested soil for management of M. ingocnita.

Longevity of Fungal Mycelia and Nuclear Quality Checks: a New Hypothesis for the Role of Clamp Connections in Dikaryons.

This paper addresses the stability of mycelial growth in fungi and differences between ascomycetes and basidiomycetes. Starting with general evolutionary theories of multicellularity and the role of sex, we then discuss individuality in fungi. Recent research has demonstrated the deleterious consequences of nucleus-level selection in fungal mycelia, favoring cheaters with a nucleus-level benefit during spore formation but a negative effect on mycelium-level fitness. Cheaters appear to generally be loss-of-fusion (LOF) mutants, with a higher propensity to form aerial hyphae developing into asexual spores. Since LOF mutants rely on heterokaryosis with wild-type nuclei, we argue that regular single-spore bottlenecks can efficiently select against such cheater mutants. We then zoom in on ecological differences between ascomycetes being typically fast-growing but short-lived with frequent asexual-spore bottlenecks and basidiomycetes being generally slow-growing but long-lived and usually without asexual-spore bottlenecks. We argue that these life history differences have coevolved with stricter nuclear quality checks in basidiomycetes. Specifically, we propose a new function for clamp connections, structures formed during the sexual stage in ascomycetes and basidiomycetes but during somatic growth only in basidiomycete dikaryons. During dikaryon cell division, the two haploid nuclei temporarily enter a monokaryotic phase, by alternatingly entering a retrograde-growing clamp cell, which subsequently fuses with the subapical cell to recover the dikaryotic cell. We hypothesize that clamp connections act as screening devices for nuclear quality, with both nuclei continuously testing each other for fusion ability, a test that LOF mutants will fail. By linking differences in longevity of the mycelial phase to ecology and stringency of nuclear quality checks, we propose that mycelia have a constant and low lifetime cheating risk, irrespective of their size and longevity.

Calcium dynamics during the growth of Agaricus bisporus: implications for mushroom development and nutrition

BackgroundAgaricus bisporus (A. bisporus) is highly valued for its nutritional benefits and delicious taste, making it one of the most widely cultivated, highest yielding, and most consumed edible mushrooms worldwide. The yield and quality of A. bisporus were affected by its culture medium and environment. Among the culture base, the precise impact of calcium on A. bisporus cultivation and the dynamic changes in calcium concentration and chemical environment during the cultivation process remain unclear. This study aims to investigate the changes in calcium content and forms during the growth of A. bisporus and their implications for mushroom growth and nutrition.ResultsThrough the analysis of samples collected during the composting phase, mycelial development phase, and A. bisporus harvesting phase, the role of calcium in the growth process of button mushrooms is revealed. During the composting phase, the calcium content remains relatively stable, suggesting a consistent calcium source in the compost. The fermentation process shows a significant decrease in carbon content and an increase in oxygen content, indicating the degradation and oxidation of organic matter. In the mycelial development phase, both the cover soil and compost experience a decrease in calcium content, with a more pronounced reduction observed in the covering soil, indicating its primary role as an energy source for enzymatic activity and metabolic processes of the mycelium. During the A. bisporus harvesting phase, the changes in calcium, carbon, and oxygen content become less prominent, indicating a stable state of fruiting bodies growth that no longer requires a significant supply of organic matter.ConclusionsAnalysis of calcium forms reveals the presence of different calcium compounds, likely influenced by soil calcium sources, microbial activities, and mushroom metabolic byproducts. Calcium plays a crucial regulatory role in the growth and quality of A. bisporus. This study provides valuable insights into the significance of calcium in A. bisporus growth and offers theoretical guidance for optimizing mushroom production and quality improvement.Graphical

Prevalence and Antifungal Susceptibility of Sporothrix species in Guangzhou, Southern China.

Sporotrichosis is a subcutaneous and chronic infection caused by traumatic inoculation of pathogenic sporothrix species, usually infecting the skins and subcutaneous tissues of humans and animals. However, the lack of epidemiological data required further molecular identification to describe the distribution of this fungus in our region. In this study, forty-eight clinical sporothrix isolated from Sun Yat-Sen Memorial Hospital were classified, and the susceptibility of each strain to seven antifungal agents was determined. Forty strains of S. globosa and eight strains of S. shenkshii were identified via colony morphology and PCR sequencing of calmodulin gene. Antifungal susceptibility tests of the mycelial phase in vitro showed terbinafine (TRB) and luliconazole (LULI) were the most effective, followed by itraconazole (ITZ) and amphotericin B (AMB). By contrast, voriconazole (VCZ), 5-flucytosine (5FC) and fluconazole (FCZ) have low efficacy with high MIC. Our results showed a predominantly S. globosa infection trend in southern China. Simultaneously, sporothrix is sensitive to TRB, LULI, ITZ and AMB whereas resistant to FCZ. This study firstly reports antifungal sensitivity test in vitro and epidemiological correlation analysis of sporothrix in southern China, and also the first time to find that sporothrix is sensitive to LULI.

Differential lipase virulence in Malassezia furfur dimorphism isolated from pityriasis versicolor patients and healthy individuals.

Malassezia furfur is a member of the human skin microbiomes that can cause various skin diseases. Dimorphism plays a role as the yeast phase predominates during skin colonisation whereas mycelial forms are observed in the scales of patients with pityriasis versicolor (PV). However, due to their condition-dependence for growth, it is difficult to culture M. furfur and this is an additional challenge for studying the pathogenicity of this fungus. To describe different media suitable for culturing Malassezia from the yeast phase into mycelial forms, with a particular focus on nutritional supplements and pH conditions. Clinical M. furfur isolates from patients with PV and healthy individuals were used to investigate Malassezia dimorphism as well as the activity and expression of lipase enzymes. Our experimental media were significantly more likely to promote mycelial growth in strains from healthy individuals compared to those from patients with PV. Lipase activity was increased in the mycelial phase cells compared to yeast forms for all strains tested. Assessment of the relative transcriptional expression of lipase within M. furfur revealed that LIP-coding genes were upregulated in mycelium relative to yeast forms for the strains tested. However, the increases in LIP3, LIP5 and LIP6 gene expressions were significantly greater in strains from healthy individuals compared to those from patients with PV. Overall, this study validated effective growth conditions to study M. furfur virulence factors and demonstrated that lipase is associated with M. furfur dimorphism.

Analysis of the cytotoxic properties of collection strains of coccidioidomycosis causative agents

Introduction. C. immitis and C. posadasii are primary pathogens and are of reasonable interest in terms of their biological properties and, in particular, cytotoxic characteristics. Aim. To study the cytotoxicity of strains of coccidioidomycosis causative agents using the MTT test on in vitro models of cell lines. Materials and methods. Strains Coccidioides spp. were cultivated in a nutrient medium intended for cell lines. Cultures Wehi 3 and HEp-2 were exposed to sterile filtrates of the growth medium of causative agents of coccidioidomycosis in various dilutions, followed by measuring the mitochondrial activity of cells in the MTT-assay on day 4. The cytotoxic properties of fungi of the genus Coccidioides were assessed by calculating the cytotoxic concentration (СС50) of the metabolic products of micromycetes. Results. The most adequate cell model was selected, as well as the conditions for setting the MTT test for the in vitro study of the cytopathogenic effects of micromycetes of the genus Coccidioides were worked out. It was found that the strains Coccidioides spp. have different intensities of metabolite production, which, in turn, does not directly correlate with their cytotoxicity. By calculating the cytotoxic concentration (CC50), data were obtained on the cytotoxic properties of 7 collection strains of coccidioidomycosis pathogens in the mycelial growth phase. Conclusion. Based on the results of assessing the mitochondrial activity of cells of the lines Wehi 3 and HEp-2, the pronounced cytotoxic properties of the collection strains of coccidioidomycosis causative agents, which were subcultured in vitro for a long time, were confirmed.

A Langmuir-Blodgett Study of the Interaction between Amphotericin B and Lipids of Histoplasma capsulatum.

Histoplasma capsulatum is a dimorphic, thermal, and nutritional fungus. In the environment and at an average temperature of 28 °C, it develops as a mold that is composed of infecting particles. Once in the host or in cultures at 37 °C, it undergoes a transition into the parasitic form. In the present work, we performed chemical extraction and characterization using chromatography techniques of the associated lipid composition of the external surface of the cell wall of the mycelial phase of two isolates of the H. capsulatum: one clinical and one environmental. Several differences were evidenced in the fatty acids in the phospholipid composition. Surface pressure–area isotherms and compression module curves of the Amphotericin B and lipid extract monolayers, as well as (AmB)-lipid extract mixed monolayers were recorded. Results show a high affinity of AmB towards lipid extracts. The most stable monolayers were formed by AmB + environmental with a mass ratio of 1:3 and AmB + clinical with a mass ratio of 1:2. Knowledge of the AmB aggregation processes at a molecular level and the characterization of the lipid extracts allows the possibility to understand the interaction between the AmB and the lipid fractions of H. capsulatum.

Key thermally dimorphic fungal pathogens: shaping host immunity.

Exposure to fungal pathogens from the environment is inevitable and with the number of at-risk populations increasing, the prevalence of invasive fungal infection is on the rise. An interesting group of fungal organisms known as thermally dimorphic fungi predominantly infects immunocompromised individuals. These potential pathogens are intriguing in that they survive in the environment in one form, mycelial phase, but when entering the host, they are triggered by the change in temperature to switch to a new pathogenic form. Considering the growing prevalence of infection and the need for improved diagnostic and treatment approaches, studies identifying key components of fungal recognition and the innate immune response to these pathogens will significantly contribute to our understanding of disease progression. This review focuses on key endemic dimorphic fungal pathogens that significantly contribute to disease, including Histoplasma, Coccidioides and Talaromyces species. We briefly describe their prevalence, route of infection and clinical presentation. Importantly, we have reviewed the major fungal cell wall components of these dimorphic fungi, the host pattern recognition receptors responsible for recognition and important innate immune responses supporting adaptive immunity and fungal clearance or the failure thereof.

Production of Ergot Alkaloids by the Japanese Isolate <i>Claviceps purpurea</i> var. <i>agropyri</i> on Rice Medium

Ergot alkaloids (EAs) are secondary metabolites produced by ergot fungi (e.g., Claviceps purpurea), which are parasites of Gramineae grasses. EAs and their analogs are used to treat migraine, postpartum uterine bleeding, and Parkinson's syndrome. Recent studies have reported additional new bioactive activities of EAs and their analogs, making them essential compounds for drug development, drug repositioning, and clinical applications. EAs are produced industrially by field cultivation of ergot or liquid fermentation in the mycelial phase, but there are few published studies of the production of EAs by cereal culture and thus this approach is poorly understood. This study searched for Claviceps strains that produce EAs cultured artificially in the mycelial phase, then the selected strains were cultured on cereal media (white rice, brown rice, and rye) to examine their ability to produce EAs on each medium. C. purpurea var. agropyri produced the Clavine-type EAs pyroclavine (1), festuclavine (2), and agroclavine (3) in the mycelial phase. When cultured with white rice, brown rice, or rye, C. purpurea var. agropyri produced 1 - 3 on all cereal media. The total amount of 1 - 3 in each cereal medium (150 g of cereal per Roux flask) was 2220.5 ± 564.1 μg for white rice, 920.0 ± 463.6 μg for brown rice, and 595.4 ± 52.1 μg for rye. The white rice medium supported the highest production of 1 - 3, with the total amount of EAs (150 g of white rice per Roux flask) being about 34 times higher than that in the T25 liquid medium (190 mL per 1 L Erlenmeyer flask) (equivalent amount per flask).

Performance of mycelium composites of Lentinus crinitus under two compression protocols

Considering the current environmental problems that has been generated by the excessive production of synthetic plastics, more sustainable alternatives have been proposed. One of these recently studied materials are the mycelium composites, a product obtained with lignocellulosic particles agglomerated together by the myceliar growth of a filamentous fungus. This novel type of materials could represent an option to replace non-biodegradable materials. In this work, mycelium composites with characteristics comparable to expanded polystyrene (EPS) and potentially suitable for fabrication of insulation panels were developed using a Lentinus crinitus strain previously selected after mycelial phases tests. Mechanical variables in bending, compression strength and stiffness were measured following ASTM D143 standard. Two protocols for composite fabrication were followed using different compression loads. Flexural strength reached 0.48 MPa and compression strength 0.235 MPa. Results obtained were compared with data of balsa wood (Ochroma pyramidale) for the similarity of possible applications, expanded polystyrene as its possible substitute and early published data on mycelium composites. Mechanical performance in flexural and compressive strength of the obtained materials revealed their potential use as biodegradable alternatives to some applications of synthetic plastics as insulation panels and packing materials.

Deletion of the Stress Response Gene DDR48 from Histoplasma capsulatum Increases Sensitivity to Oxidative Stress, Increases Susceptibility to Antifungals, and Decreases Fitness in Macrophages.

The stress response gene DDR48 has been characterized in Saccharomyces cerevisiae and Candida albicans to be involved in combating various cellular stressors, from oxidative agents to antifungal compounds. Surprisingly, the biological function of DDR48 has yet to be identified, though it is likely an important part of the stress response. To gain insight into its function, we characterized DDR48 in the dimorphic fungal pathogen Histoplasma capsulatum. Transcriptional analyses showed preferential expression of DDR48 in the mycelial phase. Induction of DDR48 in Histoplasma yeasts developed after treatment with various cellular stress compounds. We generated a ddr48∆ deletion mutant to further characterize DDR48 function. Loss of DDR48 alters the transcriptional profile of the oxidative stress response and membrane synthesis pathways. Treatment with ROS or antifungal compounds reduced survival of ddr48∆ yeasts compared to controls, consistent with an aberrant cellular stress response. In addition, we infected RAW 264.7 macrophages with DDR48-expressing and ddr48∆ yeasts and observed a 50% decrease in recovery of ddr48∆ yeasts compared to wild-type yeasts. Loss of DDR48 function results in numerous negative effects in Histoplasma yeasts, highlighting its role as a key player in the global sensing and response to cellular stress by fungi.

Mycelial Inhibition of Sclerotinia sclerotiorum by Trichoderma spp. Volatile Organic Compounds in Distinct Stages of Development.

<b>Background and Objective:</b> Fungi of the genus <i>Trichoderma </i>have high versatility in the control of different plant diseases. Among the main mechanisms of action of these fungi against phytopathogenic fungi, the production of Volatile Organic Compounds (VOCs) is mentioned. These compounds are said to inhibit the mycelial growth of various fungal pathogens. The objective of this work was to evaluate the <i>in vitro</i> inhibition of the mycelial growth of <i>Sclerotinia sclerotiorum </i>by VOCs from six <i>Trichoderma </i>strains in different stages of development of the biocontrol agent. <b>Materials and Methods:</b> In this work, the <i>in vitro </i>evaluation of the mycelial growth of the phytopathogen <i>S. sclerotiorum </i>by VOCs from six <i>Trichoderma </i>strains was carried out: <i>T. koningiopsis </i>(CEN1386), <i>T. asperelloides </i>(CEN1397), <i>T. longibrachiatum </i>(CEN1399) <i>T. lentiforme </i>(CEN1416), <i>T</i>. <i>perbedyi</i> (CEN1389) and <i>T. azevedoi</i> (CEN1241). Observations were made at different stages of antagonist development: mycelial Growth Phase (GP), Sporulation Phase (SP) and paired with the Pathogen Phase (PP). Besides, the sporulation of the tested strains was quantified. <b>Conclusion:</b> In all experimental conditions, the VOCs produced by the CEN1241 strain showed a greater inhibitory effect, although the inhibition was less evident when the cultures of <i>S. sclerotiorum </i>were exposed in the GP phase of the antagonist. Greater sporulation was observed with <i>T. lentiforme</i> (CEN1416), a fact not related to a better ability to inhibit <i>S. sclerotiorum</i>, by VOCs.

Susceptibility testing of clinical isolates of Sporothrix globosa in Shandong, China.

To evaluate the antifungal susceptibility of Sporothrix globosa isolated from Shandong, China, and compare the differences of antifungal activity in vitro between yeast and mycelial phases. The in vitro sensitivity of mycelium phase and yeast phase of Sporothrix globosa to anidulafungin, micafungin, caspofungin, 5-flucytosine, posaconazole, voriconazole, itraconazole, fluconazole and amphotericin B was tested by Sensititre™ YeastOne™. The minimum inhibitory concentration (MIC) values of mycelium phase and yeast phase were calculated. SPSS 19.0 software was used to conduct non-parametric rank sum test for MIC values, and P<.05 was considered statistically significant. The mycelium phase and yeast phase were the most sensitive to itraconazole and the least sensitive to fluconazole. The yeast phase of the same strain was more sensitive to itraconazole, voriconazole, posaconazole, micafungin, anidulafungin, caspofungin and 5-fluorouracil, compared with the mycelium (P<.05). However, fluconazole and amphotericin B had no significant difference in mycelium phase and yeast phase. Itraconazole is the most active antifungal agent in vitro against Sglobosa. The yeast phase of the same strain is more sensitive than that of the mycelium.

Denture Stomatitis: Report of a Case with Rarely Used Treatment Modality and Review of Literature

Candida albicans is the most common Candida species isolated from the oral cavity both in healthy and diseased. Candida albicans is a dimorphic fungus existing both in blastopore phase (yeast phase) and the hyphal or mycelial phase. Although these organisms typically colonize mucocutaneous surfaces, the latter can be portals of entry into deeper tissues when host defences are compromised. Denture stomatitis is a common form of oral candidiasis that manifests as a diffuse inflammation of the maxillary denture bearing areas &amp; is associated with angular cheilitis. At least 70% of individuals with clinical signs of denture stomatitis exhibit fungal growth &amp; these conditions most likely result from yeast colonization of the oral mucosa combined with Bacterial colonization. Candida species act as an endogenous infecting agent on tissue predisposed by chronic trauma to microbial invasion. At one time, oral fungal infections were rare findings in general dentist's office. They were more commonly seen in hospitalized and severely debilitated patients. However with enhanced medical and pharmaceutical technology, increasing numbers of ambulatory immunosuppressed individuals with oral fungal infections are seeking out general dentists for diagnosis and treatment of these lesions.

Transcriptome Analysis of Dimorphic Fungus Sporothrix schenckii Exposed to Temperature Stress

PurposeSporothrix schenckii is a thermally dimorphic fungus. In a saprotrophic environment or culturing at 25 °C, it grows as mycelia, whereas in host tissues or culturing at 37 °C, it undergoes dimorphic transition and division into pathogenic yeast cells. S. schenckii can cause serious disseminated sporotrichosis in immunocompromised hosts and presents an emerging global health problem. The mycelium-to-yeast transition was a consequence of the adaptive process to different environment. Some studies showed that the transition was significantly related to the virulence and pathogenesis of dimorphic fungi. However the genetic mechanisms of this complicated biological process are poorly understood.MethodOur study presented a comparative transcriptomic analysis perspective on temperature stress in a visceral isolates of S. schenckii, obtaining more genetic information related to dimorphic transition.ResultsThe 9.38 Gbp dataset was generated and assembled into 14,423 unigenes. Compared with gene and protein databases, 9561 unigenes were annotated. Comparative analysis identified 1259 genes expressed differentially in mycelium and yeast phase, and were categorized into a number of important biological processes, such as synthesis and metabolism, transmembrane transport, biocatalysis, oxidation reduction, and cellular signal transduction.ConclusionsThe findings suggested that temperature-dependent transition was tightly associated with stress adaptation, growth and development, signal regulation, adhesion, and colonization, which was predicted to be related with virulence and pathogenesis. Collection of these data should offer fine-scale insights into the mechanisms of dimorphism and pathogenesis of S. schenckii, and meanwhile facilitate the evolutionary and function studies of other dimorphic fungi.

Comparative RNAseq Analysis of the Insect-Pathogenic Fungus Metarhizium anisopliae Reveals Specific Transcriptome Signatures of Filamentous and Yeast-Like Development.

The fungus Metarhizium anisopliae is a facultative insect pathogen used as biological control agent of several agricultural pests worldwide. It is a dimorphic fungus that is able to display two growth morphologies, a filamentous phase with formation of hyphae and a yeast-like phase with formation of single-celled blastospores. Blastospores play an important role for M. anisopliae pathogenicity during disease development. They are formed solely in the hemolymph of infected insects as a fungal strategy to quickly multiply and colonize the insect’s body. Here, we use comparative genome-wide transcriptome analyses to determine changes in gene expression between the filamentous and blastospore growth phases in vitro to characterize physiological changes and metabolic signatures associated with M. anisopliae dimorphism. Our results show a clear molecular distinction between the blastospore and mycelial phases. In total 6.4% (n = 696) out of 10,981 predicted genes in M. anisopliae were differentially expressed between the two phases with a fold-change > 4. The main physiological processes associated with up-regulated gene content in the single-celled yeast-like blastospores during liquid fermentation were oxidative stress, amino acid metabolism (catabolism and anabolism), respiration processes, transmembrane transport and production of secondary metabolites. In contrast, the up-regulated gene content in hyphae were associated with increased growth, metabolism and cell wall re-organization, which underlines the specific functions and altered growth morphology of M. anisopliae blastospores and hyphae, respectively. Our study revealed significant transcriptomic differences between the metabolism of blastospores and hyphae. These findings illustrate important aspects of fungal morphogenesis in M. anisopliae and highlight the main metabolic activities of each propagule under in vitro growth conditions.