			Home About us Contact

Hyphal Tips (hyphal + tip)

Distribution by Scientific Domains

Life Sciences	75%

Selected Abstracts

Dynamic distribution of BIMGPP1 in living hyphae of Aspergillus indicates a novel role in septum formation

MOLECULAR MICROBIOLOGY, Issue 5 2002
H. Fox
Summary Mutation of bimG, the major protein phosphatase 1 gene in Aspergillus nidulans, causes multiple cell cycle and hyphal growth defects that are associated with overphosphorylation of subcellular components. We have used functional translational fusions with the green fluorescent protein (GFP) to show that BIMG has at least four discrete locations within growing hyphae. Three of these locations, the hyphal tip, the spindle pole body and the nucleus, correlate with previously known requirements for bimGPP1 in mitosis and hyphal growth and are highly dynamic. BIMG-GFP in the hyphal tip seemed to be associated with the plasma membrane and formed a collar of fluorescence within the apical dome. The distribution of nuclear BIMG-GFP varied depending on nutritional conditions; on poor medium, it concentrated more in the nucleolus than in the nucleoplasm, whereas on rich medium, it was more evenly distributed between the two nuclear regions. The association of BIMG-GFP with developing septa was transient, and we present evidence that BIMG phosphatase plays a direct role in septum formation, distinct from its role in mitosis. We conclude that, by being physically present at several sites, the BIMG phosphatase has roles in multiple cellular processes. [source]

Candida albicans ABG1 gene is involved in endocytosis

FEMS YEAST RESEARCH, Issue 2 2009
Verónica Veses
Abstract The human fungal pathogen Candida albicans undergoes reversible morphogenetic transitions between yeast, hyphal and pseudohyphal forms. The fungal vacuole actively participates in differentiation processes and plays a key role supporting hyphal growth. The ABG1 gene of C. albicans encodes an essential protein located in the vacuolar membranes of both yeast and hyphae. Using fluorescence microscopy of a green fluorescent protein-tagged version of Abg1p, a fraction of the protein was detected in hyphal tips, not associated with vacuolar membranes. Live cell imaging of emerging germ tubes showed that Abg1p migrated to the polarized growth site and colocalized with endocytic vesicles. Phenotypic analysis of a methionine-regulated conditional mutant confirmed that Abg1p is involved in endocytosis. [source]

Induction of Cell Wall Thickening by the Antifungal Compound Dihydromaltophilin Disrupts Fungal Growth and is Mediated by Sphingolipid Biosynthesis

THE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 2 2009
SHAOJIE LI
ABSTRACT. Dihydromaltophilin (heat-stable antifungal factor [HSAF]) is an antifungal metabolite produced in Lysobacter enzymogenes biocontrol strain C3. This compound induces cell wall thickening in Aspergillus nidulans. Here we show that the cell wall thickening is a general response to HSAF in diverse fungal species. In the A. nidulans model, the thickened cell wall negatively affects hyphal growth. Growth of HSAF-pre-treated hyphae failed to resume at hyphal tips with thick cell wall and the actin cable could not re-polarize at the thickened region of the cell wall, even after the treated hyphae were transferred to drug-free medium. Moreover, HSAF-induced cell wall thickening is mediated by sphingolipid synthesis: HSAF failed to induce cell wall thickening in the absence of ceramide synthase BarA and the sphingolipid synthesis inhibitor myriocin was able to suppress HSAF-induced cell wall thickening. The thickened cell wall could be digested by chitinase suggesting that chitin contributes to the HSAF-induced thickening. Furthermore, HSAF treatment activated the transcription of two chitin synthase encoding genes chsB and chsC. [source]

First report of an antifungal amidase from Peltophorum ptercoarpum

BIOMEDICAL CHROMATOGRAPHY, Issue 5 2010
Sze Kwan Lam
Abstract A 60,kDa antifungal amidase was purified from Peltophorum ptercoarpum seeds using an isolation procedure that entailed ion-exchange chromatography on Q-Sepharose, ion-exchange chromatography on DEAE-cellulose and FPLC,gel filtration on Superdex 75. Unlike most other antifungal proteins isolated previously, it was adsorbed on Q-Sepharose and DEAE-cellulose. The isolated protein, designated as peltopterin, exhibited an N -terminal amino acid sequence closely resembling those of amidases. It exhibited amidase activity and digested iodoacetamide with an optimum pH and temperature at pH 9 and 50°C, respectively. It also hydrolyzed acrylamide and urea. It impeded mycelial growth in Rhizotonia solani with an IC50 of 0.65,,m. Chitin deposition at hyphal tips in R. solani was observed by staining with Congo red after incubation with peltopterin. Its antifungal activity was stable throughout pH 0,14 and 25,100°C. It potently inhibited HIV-1 reverse transcriptase with an IC50 of 27,nm. Copyright © 2009 John Wiley & Sons, Ltd. [source]