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At least 721 records · Page 40Linked to original sources
PubMed2005

Ultrastructural analysis of the behavior of the dimorphic fungus Microbotryum violaceum in fungus-induced anthers of female Silene latifolia flowers.

The development of male organs is induced in female flowers of the dioecious plant Silene latifolia by infection with the fungus Microbotryum violaceum. Stamens in a healthy female flower grow only to stage 6, whereas those in an infected female flower develop to the mature stage (stage 12), at which the stamens are filled with fungal teliospores instead of pollen grains. To investigate these host-parasite interactions, young floral buds and fungus-induced anthers of infected female flowers were examined by electron microscopy following fixation by a high-pressure freezing method. Using this approach, we found that parasitic hyphae of this fungus contain several extracellular vesicles and have a consistent appearance up to stage 8. At that stage, parasitic hyphae are observed adjacent to dying sporogenous cells in the infected female anther. At stage 9, an increased number of dead and dying sporogenous cells is observed, among which the sporogenous hyphae of the fungus develop and form initial teliospores. Several types of electron-dense material are present in proximity to some fungi at this stage. The initial teliospores contain two types of vacuoles, and the fungus cell wall contains abundant carbohydrate, as revealed by silver protein staining. The sporogenous cell is probably sensitive to infection by the fungus, resulting in disruption. In addition, the fungus accelerates cell death in the anther and utilizes constituents of the dead host cell to form the mature teliospore.

Basidiomycota↗
PubMed2003

Evaluation of antimicrobial agents using an experimental pulmonary superinfection model with Aspergillus fumigatus and Pseudomonas aeruginosain leukopenic mice.

The therapeutic efficacy of amphotericin B (AmB), imipenem/cilastatin (IPM/CS), pazufloxacin (PZFX) mesilate, and combinations of these, was evaluated using an experimental pulmonary superinfection model in mice caused by Pseudomonas aeruginosa and Aspergillus fumigatus. The superinfected mice died within 3 days. Although the viable cell count of P. aeruginosa increased markedly from 10(3) to 10(8) CFU/lung on day 2 after infection, that of A. fumigatus decreased from 10(3) to 10(2) CFU/lung on that day, showing that P. aeruginosa facilitated the mortality in the superinfection. Extensive necrosis in the lung parenchyma and moderate hyphae proliferation of A. fumigatus were observed on day 2 after infection. Mice treated with PZFX mesilate (50 mg/kg per day) and the combination of PZFX mesilate (50 mg/kg per day) - AmB (2.5 mg/kg per day) showed prolonged survival in comparison to untreated control mice ( P < 0.05). In the PZFX mesilate-treated group, no significant necrosis was observed, but necrosis due to the hyphae proliferation of A. fumigatus was still observed in the lung parenchyma on day 6 after infection. However, neither significant necrosis nor hyphae proliferation of A. fumigatus was observed in mice treated with the combination of PZFX mesilate - AmB. On the other hand, the survival rates of mice treated with AmB (2.5 mg/kg per day), IPM/CS (50 mg/kg per day), and the IPM/CS-AmB combination were all less than 10%. The viable cell count of P. aeruginosa decreased in PZFX mesilate-alone group and in the combination of PZFX mesilate - AmB group, but no significant decrease in this count was observed in the IPM/CS and combination of IPM/CS-AmB group. The viable count of A. fumigatus was increased in the IPM/CS, PZFX mesilate-alone, and combination of IPM/CS-AmB groups, but the count was suppressed in the AmB-alone and the combination of PZFX mesilate - AmB group. In conclusion, this superinfection model would be useful to evaluate the therapeutic potential of combinations of antibacterial and antifungal agents, and the scheduling of drug administration in terminal infections caused by P. aeruginosa and A. fumigatus.

Animals↗
PubMed1981

Candidiasis and atrophic tongue lesions.

In an attempt to shed more light on the role of Candida albicans in the genesis of median rhomboid glossitis, a three-part study of normal, atrophic, and cadaver tongues was undertaken. Occasional fungal hyphae were found in 36 percent of the clinically normal tongues. Hyphae were far more numerous in cytologic smears from atrophic tongue lesions than in those from normal tongues. More than 40 percent of the cadaver tongues showed fungal hyphae. The possible role of C. albicans as a cause of median rhomboid glossitis is discussed in the light of these findings.

Adolescent↗
PubMed1979

A freeze-fracture study of hormone-induced branching in the fungus Achlya.

The induction of the male sexual organ primordia (antheridial hyphae) by the steriod hormone antheridiol in the water mold Achlya ambisexualis Raper requires the production and secretion of the enzyme cellulase. It is postulated that a localized secretion of cellulase produces a limited area of wall hydrolysis that is blown out into a lateral bleb by turgor pressure. Freeze-etch preparations show membrane profiles similar to those seen in other systems where exocytosis is occurring. Such a mechanism would provide the required localized secretion of cellulase. Water stress, imposed by polyethylene glycol, prevents the formation of antheridial hyphae, the secretion of cellulase and the expected membrane profiles. After a period of recovery from water stress antheridial hyphae are formed, cellulase secretion occurs and the expected membrane profiles are restored.

Cellulase↗
PubMed1979

Ageing of Neurospora crassa. IX. Microviscosity properties of mitochondrial membranes during normal and abnormal growth and development of an inositol auxotroph.

Microviscosity of mitochondrial membranes of an inositol auxotroph of Neurospora was measured by the method of Shinitzky, employing the fluorescent probe diphenyl-hexatriene. With high concentration of inositol, growth, morphogenesis, and cellular and biochemical phenotypes of the auxotroph are normal; whereas with low concentrations, these characteristics become abnormal and cellular and clonal senescence ensue. During normal growth and development, the critical temperatures of phase transition, the energies and volumes of fusion (delta E, V), and the microviscosities (n) at low and high temperatures changed in a cyclical "gaussian" manner; whereas the microviscosity at 25 degrees C remained constant. The normal developmental changes of the microviscosity properties were consistent with Brody's molecular packaging hypothesis, whereby the biochemical properties of conidia are pre-determined in conidiogenic hyphae. The microviscosity properties and their developmental change were closely correlated with other biochemical and biological properties such as the critical extremities of growth temperature, activity of membrane-bound cytochrome oxidase, and the stages of cellular differentiation. The thermodynamic properties of the membrane microviscosity support the genetic hypothesis that conidia and conidiogenic hyphae are more highly differentiated than growing hyphae. During abnormal growth and development, delta E and V of the liquid-crystalline phase underwent a precocious, but otherwise normal change at an early age; whereas subsequent cellular and mitochondrial senescence was accompanied by an abnormal increase of microviscosity and abnormally small delta E and V. With the results of other experiments and by analogy to proposed structural determinants of microviscosity properties of other biological membranes, a tentative interpretation of the molecular basis of the microviscosity properties and their normal and abnormal changes is derived. The effects of phospholipase treatment indicated that electrostatic interaction of phospholipid polar groups with membrane proteins may restrict mobility, increasing microviscosity and decreasing energies of fusion. Abnormal development or ageing of the membranes, leading to abnormally large n and small delta E, is probably a consequence of excessive lipid peroxidation and related abnormal changes of their structure.

Aging↗
PubMed1987

Ultrastructural localization of uranium biosorption in Penicillium digitatum by stem X-ray microanalysis.

When Penicillium digitatum Saccardo cultures are exposed to aqueous solutions containing soluble uranium salts, considerable amounts of this element are accumulated in the fungal mycelium. The accumulated uranium is retained after thorough rinsing with distilled water but is removed by alkali carbonate solutions. Analysis of thick sections (0.5 microm) of the fungal hyphae with TEM, after incubation in UO(2)Cl(2) solutions of varying concentrations under both light and dark conditions, revealed conspicuous crystal-like deposits in UO(2)Cl(2)-exposed hyphae, but none in the control hyphae. Thick sections were necessary for crystal visualization. Using energy-dispersive X-ray analysis, uranium was detected as the only heavy element in these crystals. Uranium crystal biosorption was localized on the outside surface of the hyphal cell wall (following short exposures to relatively low uranium concentrations) or inside the cell wall (following long exposure to relatively high uranium concentrations). In some cases, crystal-like deposits of uranium salts were located on the outside surface as well as inside the cell.

Journal Article↗
PubMed2005

Polycyclic aromatic hydrocarbons storage by Fusarium solani in intracellular lipid vesicles.

Accumulation and elimination of polycyclic aromatic hydrocarbons (PAHs) were studied in the fungus Fusarium solani. When the fungus was grown on a synthetic medium containing benzo[a]pyrene, hyphae of F. solani contained numerous lipid vesicles which could be stained by the lipid-specific dyes: Sudan III and Rhodamine B. The fluorescence produced by Rhodamine B and PAH benzo[a]pyrene were at the same locations in the fungal hyphae, indicating that F. solani stored PAH in pre-existing lipid vesicles. A passive temperature-independent process is involved in the benzo[a]pyrene uptake and storage. Sodium azide, a cytochrome c oxidation inhibitor, and the two cytoskeleton inhibitors colchicine and cytochalasin did not prevent the transport and accumulation of PAH in lipid vesicles of F. solani hyphae. F. solani degraded a large range of PAHs at different rates. PAH intracellular storage in lipid vesicles was not necessarily accompanied by degradation and was common to numerous other fungi.

Azo Compounds↗
PubMed2006

Optical tweezer micromanipulation of filamentous fungi.

Optical tweezers have been little used in experimental studies on filamentous fungi. We have built a simple, compact, easy-to-use, safe and robust optical tweezer system that can be used with brightfield, phase contrast, differential interference contrast and fluorescence optics on a standard research grade light microscope. We have used this optical tweezer system in a range of cell biology applications to trap and micromanipulate whole fungal cells, organelles within cells, and beads. We have demonstrated how optical tweezers can be used to: unambiguously determine whether hyphae are actively homing towards each other; move the Spitzenkörper and change the pattern of hyphal morphogenesis; make piconewton force measurements; mechanically stimulate hyphal tips; and deliver chemicals to localized regions of hyphae. Significant novel experimental findings from our study were that germ tubes generated significantly smaller growth forces than leading hyphae, and that both hyphal types exhibited growth responses to mechanical stimulation with optically trapped polystyrene beads. Germinated spores that had been optically trapped for 25min exhibited no deleterious effects with regard to conidial anastomosis tube growth, homing or fusion.

Cytological Techniques↗
PubMed2004

Fungal sinusitis: histologic spectrum and correlation with culture.

Fungi are important etiologic agents of sinusitis. However, features of fungal sinusitis including the histologic spectrum, diagnostic mishaps, incidence, and fungal types have not been systematically studied. From 1996 through 2001, a total of 788 surgical pathology sinus specimens from 384 cases was retrieved. Fungal sinusitis was diagnosed in 58 specimens (7%) from 47 cases (12%). Four histologic categories of fungal sinusitis were identified: (1) allergic fungal sinusitis in 34 cases (copious mucin, abundant eosinophils, Charcot-Leyden crystals (so-called allergic mucin), with rare noninvasive fungal hyphae); (2) mycetoma/fungus ball in 11 cases (tightly packed fungal hyphae without allergic mucin or tissue invasion); (3) chronic invasive fungal sinusitis in 1 case (tissue granulomas with fungal hyphae); and (4) acute fulminant fungal sinusitis in 1 case (fungal vascular invasion). The diagnosis was initially missed in 16/34 (47%) cases of allergic fungal sinusitis despite typical features; incorrect classification was noted in 47% of cases. Sixty-seven percent of cases had positive fungal cultures, dematiaceous fungi being the most common. Allergic fungal sinusitis accounted for the majority of fungal sinusitis. Although misdiagnosis or incorrect classification is rather frequent for fungal sinusitis, awareness of the distinctive morphologic features of this entity may prevent these errors.

Adolescent↗
PubMed2006

Detection of allergens from Alternaria alternata by gold-conjugated anti-human IgE and field emission scanning electron microscopy.

Fungal allergens are present in viable and non-viable conidia, hyphae and fungal fragments. It has been shown that large quantities of allergen are released from conidia during germination. We used a gold immunolabelling technique and field emission scanning electron microscopy to examine the allergen release from Alternaria alternata conidia. Immunolabelling was associated with the hyphal tip and amorphous matter associated with the emerging hyphae. Non-specific antibody controls showed no labelling associated with germinating fungi. This suggests that material released from hyphae may be an additional source of fungal allergens.

Allergens↗
PubMed2006

Death and decay in the trees of Mango (Mangifera indica L.).

Death and decay of trees of Mango (Mangifera indica L.) var. Kesar due to fungal infection was studied histologically. Fungal infection in the trees was observed due to various reasons like mechanical injuries in the stem, pruning of the branches, through the inflorescences, attack of Ambrosia beetle and termites. In the initial stage, fungal spores get settled on the flowers due to presence of nectar, followed by their germination and entry of the hypha into peduncle, which gradually spreads into younger branches. The inflorescences were first attacked by Fusarium moniliformis followed by other fungi like Alternaria, Chetomium sp., Aspregillus ellipticus, Aspregillus niger, etc. Fungal mycelia gradually invade the xylem tissues from the top of the branches and spread basipetally ultimately causing death of the infected branches. During monsoon, the crevices on the surface of bark of the healthy plants supported the growth of fungi like Pleurotus, Auricularia, Xyleria, Daldinia sp., and Polyporous sp. The removal of bark from such infected trees revealed minute holes on the surface of the woody cylinder made by Ambrosia beetles. During wet season fungal mycelia makes an easy entry into the xylem through the wounded portion of the stem or pruned branches. Initial entry of the hyphae into xylem was seen through the ray cells. Then the hyphae enter into the lumen of axial elements lining the ray cells through pits and intracellular spaces. The vessel elements located in the xylem (transition zone) between healthy and infected portion were filled with tyloses while axial and ray parenchyma showed heavy accumulation of tannin contents. On the other hand, the infected xylem was also found devoid of reserve metabolites while in normal trees, axial and ray parenchyma showed heavy accumulation of starch grains.

Animals↗
PubMed2006

Regulation of Streptomyces development: reach for the sky!

Streptomyces coelicolor is characterized by a complex life cycle and serves as a model system for bacterial development. After a feeding substrate mycelium has been formed, this filamentous bacterium differentiates by forming aerial hyphae that septate into spores. The bld cascade regulates initiation of aerial growth, whereas the whi genes control spore formation. Recent findings indicate the existence of another regulatory pathway that operates after aerial hyphae have started to grow into the air, which we call the sky pathway. This pathway controls the expression of the chaplin and rodlin genes. These genes encode proteins that assemble into a rodlet layer that provides surface hydrophobicity to aerial hyphae and spores.

Amino Acid Sequence↗
PubMed2005

Epizootic cutaneous pythiosis in beef calves.

Enzootic bovine granulomatosis (EBG) is a disease that affects beef calves in the flooded Savanna regions of Venezuela. Although Pythium insidiosum was originally the suspected etiologic agent, nothing was done to demonstrate its presence in the infected animals. The objective of this study was to investigate the etiologic agent causing cutaneous lesions in a group of 63 calves diagnosed with EBG. The collected samples were analyzed by histopathology, immunohistochemistry, serology, and mycological techniques. The clinical manifestations of BEG included ulcerated and swollen granulomatous lesions on the limbs of young calves. Histopathological studies revealed an eosinophilic inflammatory reaction with neutrophils, giant cells and branching hyphae with the Splendore-Hoeppli phenomenon. Immunofluorescence analysis identified the branching hyphae as elements of the fungal-like organism P. insidiosum. Wet mounts in 10% KOH revealed hyaline slender branching hyaline coenocytic hyphae, but cultures from those samples were negative. Anti-P. insidiosum immunoglobulins were also demonstrated in the collected sera of the affected bovines using latex agglutination, immunodiffusion, ELISA, and Western Blot. The histopathological, immunohistochemical, and serological tests showed for the first time that P. insidiosum could be involved in epizootic bovine pythiosis.

Animals↗
PubMed1990

Intestinal and pulmonary mycotic lymphadenitis in cattle.

Among 4877 slaughtered cattle with tuberculosis-like lesions in lymph nodes, 94 cases (1.9 per cent) revealed fungal hyphae on histopathological examination. The survey period was 12 years and most of the affected animals (greater than 77 per cent) were beef cattle. Affected nodes were mesenteric in 84 cases (89.4 per cent), mediastinal and/or bronchial in seven cases (7.4 per cent), and in three cases (3.2 per cent), both mesenteric and mediastinal nodes were affected. The incidence of mycotic lymphadenitis was unrelated to year of study or season. Eighty-two of the cases were re-examined histologically and immunohistochemically. All lesions were granulomatous in nature and, in 26 cases, eosinophilic asteroid bodies (rosette formation) around hyphae were found. In 75 cases, immunofluorescence staining identified the agent as a zygomycete, probably Absidia corymbifera and, in one case, there was a concurrent infection with a Candida species. In seven cases that did not react with the antibodies employed, a diagnosis of zygomycosis was suggested on the basis of hyphal morphology. Hyphae of Aspergillus spp. were not found in any of the lesions. A concurrent fungal and mycobacterial infection (M. avium) was diagnosed in one case. Thus, zygomycetes are the main cause of macroscopically apparent mycotic lymphadenitis, a sporadic disease most probably caused by feeding with mouldy food stuffs.

Animals↗
PubMed1996

Caprine mastitis due to aspergillosis and zygomycosis: a pathological and immunohistochemical study.

Of 73 goats on a dairy farm, 27 developed mycotic mastitis in the post-partum period. Purulent mammary secretion, progressive induration of the affected glands, slight fever and weight loss were observed. As treatment produced no improvement within 2-3 weeks, all diseased animals were slaughtered. At post-mortem examination, widespread acute and chronic mycotic lesions were seen throughout the affected glands. Infection was thought to have spread through the milk ducts as an ascending infection resulting from prophylactic intramammary treatment with antibiotic before parturition. In all lesions, aspergillus hyphae were identified by indirect immunofluorescent labelling, which gave a strong and uniform reaction with polyclonal and monoclonal antibodies to Aspergillus fumigatus. In a single granulomatous lesion, zygomycotic hyphae were also identified immunohistochemically. At terminal swellings of aspergillus hyphae, "yeast-like bodies" were produced, a phenomenon which seems to be associated with special, but unknown, circumstances.

Animals↗
PubMed1989

Cutaneous mucormycosis.

We report two cases of primary cutaneous mucormycosis in immunocompromised patients. Although their clinical presentation showed nonspecific necrotic ulcers, the histopathologic features were diagnostic. In both cases, broad, branching, nonseptate hyphae were found in the dermis and subcutaneous tissue. In one case the hyphae could be observed in the epidermis. To our knowledge, this is the only reported case of primary cutaneous mucormycosis with hyphae detectable in the epidermis.

Adult↗
PubMed1999

Gravitropism of basidiomycetous fungi--on Earth and in microgravity.

In order to achieve perfect positioning of their lamellae for spore dispersal, fruiting bodies of higher fungi rely on the omnipresent force gravity. Only accurate negatively gravitropic orientation of the fruiting body cap will guarantee successful reproduction. A spaceflight experiment during the STS-55 Spacelab mission in 1993 confirmed that the factor gravity is employed for spatial orientation. Most likely every hypha in the transition zone between the stipe and the cap region is capable of sensing gravity. Sensing presumably involves slight sedimentation of nuclei which subsequently causes deformation of the net-like arrangement of F-actin filament strands. Hyphal elongation is probably driven by hormone-controlled activation and redistribution of vesicle traffic and vesicle incorporation into the vacuoles and cell walls to subsequently cause increased water uptake and turgor pressure. Stipe bending is achieved by way of differential growth of the flanks of the upper-most stipe region. After reorientation to a horizontal position, elongation of the upper flank hyphae decreases 40% while elongation of the lower flank slightly increases. On the cellular level gravity-stimulated vesicle accumulation was observed in hyphae of the lower flank.

Basidiomycota↗
PubMed2000

First isolation of Exophiala dermatitidis from a dog: identification by molecular analysis.

The present study deals with the first isolation of Exophiala dermatitidis from a dog. The dog had a history of multicentric lymphoma for 4 months. On physical examination, 10-15 black or purple subcutaneous nodules were detected on the dorsum of the right neck. Microscopic examination of biopsy specimen from the nodules disclosed lymphocytes, neutrophils and moniliform hyphae. The colony of the clinical isolate was flat with black aerial hyphae and a wet margin after 2 weeks incubation on Sabouraud's dextrose agar at 27 degrees C. The microscopic examination of the clinical isolate revealed that hyphae were brown, septate, and smooth, producing branched or unbranched conidiospores laterally or on the apex. The conidia were one celled, subglobose, elliptical to cylindrical, smooth and hyaline. Nucleotide sequence analysis of the chitin synthase 2 (CHS2) gene fragments from the isolate and a reference strain of E. dermatitidis showed more than 99% similarity.

Animals↗