High Stability Hypha-Like Core-Shell Nanostructure by In Situ Induced Phase Inversion for Zinc Metal Batteries.

Nanomaterials are widely used in many fields for their unique physical and chemical properties and especially demonstrate irreplaceability in energy storage systems. In this paper, a novel composite of copper sulfide with hypha-like core-shell nano-structure is synthesized by in situ phase inversion method, which serves as high stability negative electrode materials of zinc-ion batteries (ZIBs). The unique structure facilitates efficient electron and ion transport, enhances the kinetics of electrochemical reactions, and effectively suppresses the undesired expansion and decomposition of transition metal compounds. As a result, the half battery exhibits high specific capacity (250.2 mAh g-1 at 0.1 A g-1), reliable rate performance, and cycle stability (98.3 mAh g-1 at 1 A g-1 after 500 cycles). Additionally, when assembled with ZnxMnO2 positive to form a full battery, it demonstrates good cycling capacity at an intermediate current density of 2 A g-1, while maintaining excellent structural stability over 5,000 cycles (61% retention).

Coregulation of dimorphism and symbiosis by cyclic AMP signaling in the lichenized fungus Umbilicaria muhlenbergii.

Umbilicaria muhlenbergii is the only known dimorphic lichenized fungus that grows in the hyphal form in lichen thalli but as yeast cells in axenic cultures. However, the regulation of yeast-to-hypha transition and its relationship to the establishment of symbiosis are not clear. In this study, we show that nutrient limitation and hyperosmotic stress trigger the dimorphic change in U. muhlenbergii Contact with algal cells of its photobiont Trebouxia jamesii induced pseudohyphal growth. Treatments with the cAMP diphosphoesterase inhibitor IBMX (3-isobutyl-1-methylxanthine) induced pseudohyphal/hyphal growth and resulted in the differentiation of heavily melanized, lichen cortex-like structures in culture, indicating the role of cAMP signaling in regulating dimorphism. To confirm this observation, we identified and characterized two Gα subunits UmGPA2 and UmGPA3 Whereas deletion of UmGPA2 had only a minor effect on pseudohyphal growth, the ΔUmgpa3 mutant was defective in yeast-to-pseudohypha transition induced by hyperosmotic stress or T. jamesii cells. IBMX treatment suppressed the defect of ΔUmgpa3 in pseudohyphal growth. Transformants expressing the UmGPA3G45V or UmGPA3Q208L dominant active allele were enhanced in the yeast-to-pseudohypha transition and developed pseudohyphae under conditions noninducible to the wild type. Interestingly, T. jamesii cells in close contact with pseudohyphae of UmGPA3G45V and UmGPA3Q208L transformants often collapsed and died after coincubation for over 72 h, indicating that improperly regulated pseudohyphal growth due to dominant active mutations may disrupt the initial establishment of symbiotic interaction between the photobiont and mycobiont. Taken together, these results show that the cAMP-PKA pathway plays a critical role in regulating dimorphism and symbiosis in U. muhlenbergii.

Anti-Biofilm Activity of Cocultimycin A against Candida albicans.

Candida albicans (C. albicans), the most common fungal pathogen, has the ability to form a biofilm, leading to enhanced virulence and antibiotic resistance. Cocultimycin A, a novel antifungal antibiotic isolated from the co-culture of two marine fungi, exhibited a potent inhibitory effect on planktonic C. albicans cells. This study aimed to evaluate the anti-biofilm activity of cocultimycin A against C. albicans and explore its underlying mechanism. Crystal violet staining showed that cocultimycin A remarkably inhibited biofilm formation in a dose-dependent manner and disrupted mature biofilms at higher concentrations. However, the metabolic activity of mature biofilms treated with lower concentrations of cocultimycin A significantly decreased when using the XTT reduction method. Cocultimycin A could inhibit yeast-to-hypha transition and mycelium formation of C. albicans colonies, which was observed through the use of a light microscope. Scanning electron microscopy revealed that biofilms treated with cocultimycin A were disrupted, yeast cells increased, and hypha cells decreased and significantly shortened. The adhesive ability of C. albicans cells treated with cocultimycin A to the medium and HOEC cells significantly decreased. Through the use of a qRT-PCR assay, the expression of multiple genes related to adhesion, hyphal formation and cell membrane changes in relation to biofilm cells treated with cocultimycin A. All these results suggested that cocultimycin A may be considered a potential novel molecule for treating and preventing biofilm-related C. albicans infections.

Reprogramming in Candida albicans Gene Expression Network under Butanol Stress Abrogates Hyphal Development.

Candida albicans is the causative agent of invasive fungal infections. Its hyphae-forming ability is regarded as one of the important virulence factors. To unravel the impact of butanol on Candida albicans, it was placed in O+ve complete human serum with butanol (1% v/v). The Candida transcriptome under butanol stress was then identified by mRNA sequencing. Studies including electron microscopy demonstrated the inhibition of hyphae formation in Candida under the influence of butanol, without any significant alteration in growth rate. The numbers of genes upregulated in the butanol in comparison to the serum alone were 1061 (20 min), 804 (45 min), and 537 (120 min). Candida cells exhibited the downregulation of six hypha-specific transcription factors and the induction of four repressor/regulator genes. Many of the hypha-specific genes exhibited repression in the medium with butanol. The genes related to adhesion also exhibited repression, whereas, among the heat-shock genes, three showed inductions in the presence of butanol. The fungal-specific genes exhibited induction as well as repression in the butanol-treated Candida cells. Furthermore, ten upregulated genes formed the core stress gene set in the presence of butanol. In the gene ontology analysis, enrichment of the processes related to non-coding RNA, ribosome biosynthesis, and metabolism was observed in the induced gene set. On the other side, a few GO biological process terms, including biofilm formation and filamentous growth, were enriched in the repressed gene set. Taken together, under butanol stress, Candida albicans is unable to extend hyphae and shows growth by budding. Many of the genes with perturbed expression may have fitness or virulence attributes and may provide prospective sites of antifungal targets against C. albicans.

Paeonol assists fluconazole and amphotericin B to inhibit virulence factors and pathogenicity of Candida albicans.

This study aimed to evaluate the mono- and dual- antifungal activities of paeonol (PAE) and fluconazole (FLZ)/amphotericin B (AmB). To this end, the effects of PAE and FLZ/AmB on cell surface hydrophobicity, hydrolase activity, morphological transition were investigated in vitro and in a Galleria mellonella infection model. The results showed a relatively high minimum inhibitory concentration (MIC) and sessile MIC (SMIC) of PAE alone. However, compared with the single drug, the combined use of PAE and FLZ/AmB had a potent synergistic potential to inhibit the virulence factors for Candida. The concomitant use of two drugs was consistently more effective than either drug alone for increasing survival rate, decreasing the fungal burden, and alleviating the pathological features of G. mellonella infected by the fungus. Taken together, these findings demonstrate the anti-Candida effects of PAE plus FLZ/AmB and their potential to increase the sensitivity of C. albicans to FLZ/AmB of PAE.

Hypha essential genes in Candida albicans pathogenesis of oral lichen planus: an in-vitro study.

BACKGROUND: Hypha essential genes (HEGs) of Candida Albicans have been emerging into scholar's attention, little known about their functions in oral lichen planus (OLP) with an uncovered etiology. This research aimed to observe necessary genes in biphasic C. albicans from OLP and study their relevance in pathogenesis, so as to evaluate possible roles of morphologic switching in etiology of OLP. METHODS: Samples were collected from OLP lesions of patients, mycelia were cultured and total RNA was extracted then subjected to reverse transcription-PCR and real-time PCR. RESULTS: HWP1 and HGC1 were significantly expressed in hyphae phase and weakly detected in yeast phase, while there was no significant difference of EFG1, ALS3, and ECE1 between in yeast and mycelia. CONCLUSION: HGC1 and HWP1 were confirmed to be hypha essential genes, with HGC1 for hypha morphogenesis and HWP1 for adhesion invasion in pathogenesis of C. albicans in OLP. ALS3, ECE1 and EFG1 played minor roles in hyphae maintenance and adhesion for hyphae. These might be deemed as hints for the etiology of OLP and indicate HGC1 and HWP1 to be a priority of potential drug target.

[Effect of berberine hydrochloride on cell wall integrity of Candida albicans hypha].

The aim of this paper was to investigate the effect of berberine hydrochloride on the cell wall integrity of Candida albicans hypha. The minimal inhibitory concentration(MIC) of berberine hydrochloride against clinical and standard C. albicans strains was detected by micro liquid-based dilution method; the effect of berberine hydrochloride on the colony formation of C. albicans SC5314 was investigated by spot assay; the effect of berberine hydrochloride on the metabolism of C. albicans SC5314 hypha was checked by XTT reduction assay, and the viability of C. albicans SC5314 hypha was tested by fluorescent staining assay. The effect of berberine hydrochloride on the morphology of C. albicans SC5314 hypha was examined by scanning electron microscope. The changes in the cell wall of C. albicans SC5314 hypha after berberine hydrochloride treatment were detected by transmission electron microscopy. The effect of berberine hydrochloride on ß-glucan from C. albicans SC5314 was detected by flow cytometry. The effect of berberine hydrochloride on hypha-specific gene ECE1 and ß-glucan synthase genes FKS1 and FKS2 in C. albicans was examined by qRT-PCR. The results showed that berberine hydrochloride showed a strong inhibitory effect on both clinical and standard strains of C. albicans, and the MIC was 64-128 µg·mL~(-1). Spot assay, XTT redunction assay and fluorescent staining assay showed that with the increase of berberine hydrochloride concentration, the viability of C. albicans SC5314 gradually decreased. The transmission electron microscopy scanning assay showed that this compound could cause cell wall damage of C. albicans. The flow cytometry analysis showed the exposure degree of C. albicans ß-glucan. The qRT-PCR further showed that berberine hydrochloride could significantly down-regulate hypha-specific gene ECE1 and ß-glucan synthase-related gene FKS1 and FKS2. In conclusion, this compound can down-regulate C. albicans and ß-glucan synthase-related gene expressions, so as to destroy the cell wall structure of C. albicans, expose ß-glucan and damage the integrity of the wall.

The C3HC type zinc-finger protein (ZFC3) interacting with Lon/MAP1 is important for mitochondrial gene regulation, infection hypha development and longevity of Magnaporthe oryzae.

BACKGROUND: The rice blast is a typical fungal disease caused by Magnaporthe oryzae, and the mitochondrial ATP-dependent Lon protease (MAP1) has been proven to be involved in blast development. We previously screened a C3HC type Zinc-finger domain protein (ZFC3), which is interacted with MAP1. The purpose of this research was to study the biological function of ZFC3 protein in M. oryzae. RESULTS: We first confirmed that the ZFC3-RFP fusion protein is localized within the mitochondria. The deleted mutant strains of ZFC3 (∆ZFC3) showed the enhanced expression level of mtATP6, particularly mtATP8, and almost unchanged nATP9. ΔZFC3 produces more conidia and more tolerance to multiple stressors. The knock-out strain shows more melanin accumulation suggests the susceptibility to aging. ΔZFC3 displays faster early-stage hypha infiltration involved in MAP1-mediated pathogenicity in host rice. CONCLUSION: These results support the view that ZFC3 is a key regulator involved in gene regulation, stress response, cell wall integrity, longevity, conidiation, infection hypha development and MAP1-mediated pathogenicity in M. oryzae.

Modelling fungal hypha tip growth via viscous sheet approximation.

In this paper we present a new model for single-celled, non-branching hypha tip growth. The growth mechanism of hypha cells consists of transport of cell wall building material to the cell wall and subsequent incorporation of this material in the wall as it arrives. To model the transport of cell wall building material to the cell wall we follow Bartnicki-Garcia and Gierz in assuming that the cell wall building material is transported in straight lines by an isotropic point source. To model the dynamics of the cell wall, including its growth by new material, we use the approach of Campàs and Mahadevan, which assumes that the cell wall is a thin viscous sheet sustained by a pressure difference. Furthermore, we include a novel equation which models the hardening of the cell wall as it ages. We validate the new model by comparing it to experimental data.

In vitro efficacy of the lipopeptide biosurfactant surfactin-C15 and its complexes with divalent counterions to inhibit Candida albicans biofilm and hyphal formation.

Surfactin is a type of cyclic lipopeptide biosurfactant implicated in a wide range of applications. Although its antimicrobial activity has been characterized, its effect on Candida albicans physiology remains to be elucidated. The present study evaluated the influence of surfactin-C15 (SF) and its complexes with divalent counterions on C. albicans biofilm formation and preformed biofilms. The SF and metal(II)-SF complexes inhibited biofilm formation and reduced the metabolic activity of mature biofilms in a concentration-dependent manner. The same concentrations of the compounds studied dislodged preexisting biofilms grown on polystyrene plates. Moreover, SF and its metal(II) complexes reduced the mRNA expression of hypha-specific genes HWP1, ALS1, ALS3, ECE1 and SAP4 without exhibiting significant growth inhibition. Further research showed that the compounds tested reduced cellular surface hydrophobicity (CSH). These results suggest that SF and metal(II)-SF complexes could be used as anti-biofilm agents against C. albicans hypha-related infections in clinical practice.

Inhibition of Yeast-to-Hypha Transition and Virulence of Candida albicans by 2-Alkylaminoquinoline Derivatives.

A rapid increase in Candida albicans infection and drug resistance has caused an emergent need for new clinical strategies against this fungal pathogen. In this study, we evaluated the inhibitory activity of a series of 2-alkylaminoquinoline derivatives against C. albicans isolates. A total of 28 compounds were assessed for their efficacy in inhibiting the yeast-to-hypha transition, which is considered one of the key virulence factors in C. albicans Several compounds showed strong activity to decrease the morphological transition and virulence of C. albicans cells. The two leading compounds, compound 1 (2-[piperidin-1-yl]quinolone) and compound 12 (6-methyl-2-[piperidin-1-yl]quinoline), remarkably attenuated C. albicans hyphal formation and cytotoxicity in a dose-dependent manner, but they showed no toxicity to either C. albicans cells or human cells. Intriguingly, compound 12 showed an excellent ability to inhibit C. albicans infection in the mouse oral mucosal infection model. This leading compound also interfered with the expression levels of hypha-specific genes in the cyclic AMP-protein kinase A and mitogen-activated protein kinase signaling pathways. Our findings suggest that 2-alkylaminoquinoline derivatives could potentially be developed as novel therapeutic agents against C. albicans infection due to their interference with the yeast-to-hypha transition.

Molecular studies of NAD- and NADP-glutamate dehydrogenases decipher the conundrum of yeast-hypha dimorphism in zygomycete Benjaminiella poitrasii.

Benjaminiella poitrasii, a zygomycete, shows glucose- and temperature-dependent yeast (Y)-hypha (H) dimorphic transition. Earlier, we reported the biochemical correlation of relative proportion of NAD- and NADP-glutamate dehydrogenases (GDHs) with Y-H transition. Further, we observed the presence of one NAD-GDH and two form-specific NADP-GDH isoenzymes in B. poitrasii. However, molecular studies are necessary to elucidate the explicit role of GDHs in regulating Y-H reversible transition. Here, we report the isolation and characterization of one NAD (BpNADGDH, 2.643 kb) and two separate genes, BpNADPGDH I (Y-form specific, 1.365 kb) and BpNADPGDH II (H-form specific, 1.368 kb) coding for NADP-GDH isoenzymes in B. poitrasii. The transcriptional profiling during Y-H transition showed higher BpNADPGDH I expression in Y cells while expression of BpNADPGDH II was higher in H cells. Moreover, the yeast-form monomorphic mutant (Y-5) did not show BpNADPGDH II expression under normal dimorphism triggering conditions. Transformation with H-form specific BpNADPGDH II induced the germ tube formation in Y-5, which confirmed the cause-effect relationship between BpNADPGDH genes and morphological outcome in B. poitrasii. Interestingly, expression of H-form specific BpNADPGDH II also induced germ tube formation in human pathogenic, non-dimorphic yeast Candida glabrata, which further corroborated our findings.

Efficacy of Compounds Isolated from Streptomyces olivaceus against the Morphogenesis and Virulence of Candida albicans.

Candida albicans is a type of commensal fungi which causes serious infections in immunocompromised patients and contributes to high mortality. In the present study, we identified that the extract from Streptomyces olivaceus SCSIO T05 inhibited hypha and biofilm formation of C. albicans. Seven compounds were isolated and evaluated for their effects on the biological functions and virulence of C. albicans. Two leading compounds, compound 1 (sorbicillin) and compound 2 (3-methyl-N-(2'-phenethyl)-butyrylamide) were identified as exhibiting strong activity against C. albicans morphological transition, adhesion activity, cytotoxicity, and adhesion to human cells, in a dose-dependent manner. Notably, compound 2 inhibited C. albicans infection in mouse oral mucosal models. Transcriptomic analysis and real-time PCR results revealed that compound 2 most likely inhibited the biological functions of C. albicans cells by regulating the expression levels of HWP1, TEC1, ALS1, IFD6, and CSH1, which are associated with filament formation and cell adhesion. Our results suggest that the candidate compounds present excellent efficacy against C. albicans pathogenicity and that they can be developed as potential options for the clinical treatment of candidiasis.

Hyphal chemotropism in fungal pathogenicity.

The ability to grow as filamentous hyphae defines the lifestyle of fungi. Hyphae are exposed to a variety of chemical stimuli such as nutrients or signal molecules from mating partners and host organisms. How fungi sense and process this chemical information to steer hyphal growth is poorly understood. Saccharomyces cerevisiae and Neurospora crassa have served as genetic models for the identification of cellular components functioning in chemotropism. A recent study in the pathogen Fusarium oxysporum revealed distinct MAPK pathways governing hyphal growth towards nutrient sources and sex pheromones or plant signals, suggesting an unanticipated complexity of chemosensing during fungus-host interactions.

Yeast and Filaments Have Specialized, Independent Activities in a Zebrafish Model of Candida albicans Infection.

Candida albicans dimorphism is a crucial virulence factor during invasive candidiasis infections, which claim the lives of nearly one-half of those afflicted. It has long been believed that filaments drive tissue invasion and yeast mediates bloodstream dissemination, but observation of these activities during infection has been prevented by technical limitations. We used a transparent zebrafish infection model to analyze more comprehensively how C. albicans utilizes shape to disseminate and invade. This model facilitated the use of diverse, complementary strategies to manipulate shape, allowing us to monitor dissemination, invasion, and pathogenesis via intravital imaging of individual fungal cells throughout the host. To control fungal cell shape, we employed three different strategies: gene deletion (efg1Δ/Δ cph1Δ/Δ, eed1Δ/Δ), overexpression of master regulators (NRG1 or UME6), and modulation of the infection temperature (21°C, 28°C, or 33°C). The effects of these orthogonal manipulations were consistent, support the proposed specialized roles of yeast in dissemination and filaments in tissue invasion and pathogenesis, and indicate conserved mechanisms in zebrafish. To test if either morphotype changes the effectiveness of the other, we infected fish with a known mixture of shape-locked strains. Surprisingly, mixed-strain infections were associated with additive, but not synergistic, filament invasion and yeast dissemination. These findings provide the most complete view of morphotype-function relationships for C. albicans to date, revealing independent roles of yeast and filaments during disseminated candidiasis.

Arabinogalactan Proteins Accumulate in the Cell Walls of Searching Hyphae of the Stem Parasitic Plants, Cuscuta campestris and Cuscuta japonica.

Stem parasitic plants (Cuscuta spp.) develop a specialized organ called a haustorium to penetrate their hosts' stem tissues. To reach the vascular tissues of the host plant, the haustorium needs to overcome the physical barrier of the cell wall, and the parasite-host interaction via the cell wall is a critical process. However, the cell wall components responsible for the establishment of parasitic connections have not yet been identified. In this study, we investigated the spatial distribution patterns of cell wall components at a parasitic interface using parasite-host complexes of Cuscuta campestris-Arabidopsis thaliana and Cuscuta japonica-Glycine max. We focused on arabinogalactan proteins (AGPs), because AGPs accumulate in the cell walls of searching hyphae of both C. campestris and C. japonica. We found more AGPs in elongated haustoria than in pre haustoria, indicating that AGP accumulation is developmentally regulated. Using in situ hybridization, we identified five genes in C. campestris that encode hyphal-expressed AGPs that belong to the fasciclin-like AGP (FLA) family, which were named CcFLA genes. Three of the five CcFLA genes were expressed in the holdfast, which develops on the Cuscuta stem epidermis at the attachment site for the host's stem epidermis. Our results suggest that AGPs are involved in hyphal elongation and adhesion to host cells, and in the adhesion between the epidermal tissues of Cuscuta and its host.

Messenger RNA transport in the opportunistic fungal pathogen Candida albicans.

Candida albicans, a common commensal fungus, can cause disease in immunocompromised hosts ranging from mild mucosal infections to severe bloodstream infections with high mortality rates. The ability of C. albicans cells to switch between a budding yeast form and an elongated hyphal form is linked to pathogenicity in animal models. Hyphal-specific proteins such as cell-surface adhesins and secreted hydrolases facilitate tissue invasion and host cell damage, but the specific mechanisms leading to asymmetric protein localization in hyphae remain poorly understood. In many eukaryotes, directional cytoplasmic transport of messenger RNAs that encode asymmetrically localized proteins allows efficient local translation at the site of protein function. Over the past two decades, detailed mechanisms for polarized mRNA transport have been elucidated in the budding yeast Saccharomyces cerevisiae and the filamentous fungus Ustilago maydis. This review highlights recent studies of RNA-binding proteins in C. albicans that have revealed intriguing similarities to and differences from known fungal mRNA transport systems. I also discuss outstanding questions that will need to be answered to reach an in-depth understanding of C. albicans mRNA transport mechanisms and the roles of asymmetric mRNA localization in polarized growth, hyphal function, and virulence of this opportunistic pathogen.

Phospholipid flippases DnfA and DnfB exhibit differential dynamics within the A. nidulans Spitzenkörper.

The Spitzenkörper is a structure at the apex of growing cells in many filamentous fungi. Ultrastructural studies indicate that the Spitzenkörper is an organized mass of secretory vesicles, with different types of vesicles present in outer and inner layers. Here, we used live-cell imaging to demonstrate that the phospholipid flippases DnfA and DnfB, which preferentially localize to the outer and inner layers, respectively, exhibit different dynamics in the Spitzenkörper of Aspergillus nidulans. Additionally, deletion of dnfA partially destabilized the Spitzenkörper, while the depletion of cdc50, an essential ß-subunit of most flippases, had dramatic effects on hyphal tip organization and morphology.

17ß-Estradiol inhibits estrogen binding protein-mediated hypha formation in Candida albicans.

Candida albicans is one of the most prevalent and clinically important fungal pathogens. The ability to change form depending on environmental stress is an important microbial virulence factor. A survey of compounds that inhibit this morphological change identified various steroids, including 17ß-estradiol. Interestingly, C. albicans has proteins capable of binding to steroids, including estrogen binding protein (Ebp1). Estrogens regulate cell differentiation and proliferation in humans through estrogen receptor proteins. To determine whether EBP1 regulates a virulence factor, we investigated the effect of 17ß-estradiol on the morphological transition of C. albicans using an ebp1 deletion mutant. Treatment with 10 µg/mL of 17ß-estradiol inhibited hypha formation, whereas its effect on the ebp1 deletion mutant was decreased compared to that on the wild-type and revertant strains. These data suggest a new pathway for the yeast-to-hypha transition via EBP1 in C. albicans.

Structural character evolution in Pucciniomycotina: mitosis, septa, and hyphal branch initiation in two Helicogloea species.

Early diverging taxa of Ascomycota and Basidiomycota share similarities in subcellular characters of the spindle pole body (SPB), nuclear division, and septal pore apparatus, but our understanding of character evolution is incomplete because of the limited number of structural studies within the earliest diverging subphyla of Dikarya, Taphrinomycotina and Pucciniomycotina. Two species of Helicogloea (Atractiellomycetes) were analyzed for these characters and provide data on SPB and nuclear division for an additional class of Pucciniomycotina. A detailed analysis of septal pore apparatus for the Helicogloea species permits comparisons with those of other Pucciniomycotina and Ascomycota. The endogenous origin of hyphal branches is shown to occur in a third class of Pucciniomycotina. The full set of characters supports a close relationship between Atractiellomycetes and Pucciniomycetes.