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17 recordsLinked to original sources
PubMed2006

A class Vb chitin synthase in Colletotrichum graminicola is localized in the growing tips of multiple cell types, in nascent septa, and during septum conversion to an end wall after hyphal breakage.

Previous complementation of a chitin synthase class Vb null mutant (Colletotrichum graminicola chsA) indicated that the encoded protein is responsible for approximately 30% of the conidial chitin, is essential for conidial wall strength in media with high water potential, and contributes to strength of hyphal tips. We complemented a chsA null mutant with chsA fused to the green-fluorescent protein (sgfp) gene driven by a heterologous constitutively expressed promoter. Comparisons of the strain with the ectopic chsA-sgfp to the wild type indicated that ChsA-sGFP serves the same biological functions as ChsA in that like the wild type, the chsADelta chsA::sgfp (EC) had conidia that did not explode and hyphal tips that did not swell. Confocal microscopy of ChsA-sGFP (EC) cells stained with the membrane stain FM 4-64 (N-(3-triethylammoniumpropyl)-4-(6-(4-(diethylamino)phenyl)hexatrienyl)pyridinium dibromide) indicated that ChsA is localized in the plasma membrane of the following: growing apices of hyphal branches, conidiophores, and falcate and oval conidia; in nascent septa; and in septa that are being converted to an end wall after hyphal breakage. The data support the hypothesis that chsA either directly or indirectly encodes the information for its localization, that ChsA is localized in the plasma membrane, and that the class Vb enzyme produces chitin synthase in multiple cells and after wall breakage.

Cell Membrane↗
PubMed1994

Disseminated Scedosporium prolificans (S. inflatum) infection after single-lung transplantation.

This report concerns the first case of disseminated infection with Scedosporium prolificans (S. inflatum) that occurred in a patient who had received an organ transplant and was verified at autopsy. The patient underwent single (right)-lung transplantation and subsequently died on the 33rd postoperative day in a context of septic shock. S. prolificans was isolated from various specimens, including two cultured blood samples. The organism was associated with Candida albicans in some of these specimens. Autopsy revealed the presence of numerous nodular abscesses in the lungs, myocardium, kidneys, spleen, and gall bladder. These abscesses contained mycelial filaments and numerous oval conidia suggestive of Scedosporium species but no yeasts. MIC studies demonstrated the resistance of the S. prolificans isolate to amphotericin B, fluctyosine, miconazole, ketoconazole, and itraconazole, whereas the isolate of C. albicans was susceptible to amphotericin B, flucytosine, miconazole, and ketoconazole. From the data from our case and six published reports of cases of disseminated S. prolificans infection, it can be concluded that this filamentous fungus is a new agent responsible for the most serious mycoses in both neutropenic patients and patients who have undergone organ transplantation.

Candidiasis↗
PubMed2002

Pyogranulomatous meningoencephalitis associated with dematiaceous fungal (Cladophialophora bantiana) infection in a domestic cat.

A 6-month-old, castrated male domestic cat with progressive neurological signs of 2-3 weeks duration was necropsied. Macroscopic findings were restricted to the brain and included irregularly shaped, well-delineated but unencapsulated areas of intense black pigmentation involving the rostral portion of both cerebral hemispheres. Microscopically, numerous brown, oblong, segmented branching hyphae and conidial-like structures and extensive pyogranulomatous inflammation were identified throughout the cerebral lesion and in adjacent blood vessels. Hyphae and oval conidia were best demonstrated with either Gomori methenamine silver or periodic acid-Schiff stain. Fungal infection in the brain of this cat was unrelated to any concurrent immunodeficiency syndrome or immunosuppressive treatment. This report deals with a case of cerebral phaeohyphomycosis from which a different species of dematiaceous fungus, Cladophialophora bantiana, was isolated and identified.

Animals↗
PubMed1991

Tolypocladium terricola sp. N., a new mosquito-killing species of the genus Tolypocladium Gams (Hyphomycetes).

A new entomopathogenic species of the genus Tolypocladium, T. terricola is described from a soil sample from Finalnd. From other known Tolypocladium species, T. terricola differs in morphology, production of secondary metabolites and possession of relatively strong mosquitocidal activity. The fungus is characterized by broad oval conidia (2.5 x 2 microns) with one pointed end which are produced in grape-like clusters, and are not firmly adherent. When treated with T. terricola, mosquito larvae show typical features of intoxication characterized by the concentration of larvae in the centre of cup, hanging by their siphons on the surface.

Animals↗
PubMed2026

Spore type-specific gene expression profiles underlying development and leaf infection processes of Colletotrichum graminicola.

Colletotrichum graminicola causes significant losses of the staple crop maize worldwide. The fungus produces two distinct asexual spore types, oval and falcate conidia, which show unique processes in development and plant interaction. Based on genome resequencing of our laboratory strain (CgM2/M1.001), we investigated the gene expression profiles of oval and falcate conidia during development and early leaf infection using RNA-seq. Our results reveal specific gene expression profiles between the two spore types, indicating fundamental differences in their developmental programs that reflect different modes of infection. We identified expression patterns discriminating both conidia types from mycelium and spore type-specific ones for genes encoding transcription factors, conserved fungal developmental genes, transporters, genes of secondary metabolite clusters, and pathogenicity-related functions, including effectors and carbohydrate-active enzymes (CAZymes). Our study shows that despite the identical genomic basis, oval and falcate conidia show unique transcriptomes across vegetative development and early plant interaction. Taking together, these results provide new insights into the molecular mechanisms determining the biology of C. graminicola and its interaction with the plant host.

Colletotrichum graminicola↗
PubMedDate not supplied

Pulmonary sporotrichosis with hyphae in a human immunodeficiency virus-infected patient. A case report.

BACKGROUND: Pulmonary sporotrichosis is a rare event. Sporothrix schenckii is a dimorphic fungus and develops at 37 degrees C in yeast form. Usually hyphae are not observed in tissues, although their presence has been occasionally demonstrated in biopsies. CASE: A 37-year-old man, human immunodeficiency virus-1 positive, with a CD4 cell count of 345/mm3, developed a productive cough. A sputum smear revealed the presence of a large amount of long, thin, septated micelia. The hyphae bore oval, sessile conidia. Cultures of sputum yielded numerous colonies of S schenckii. CONCLUSION: This is the first report of hyphae of S schenckii in sputum. This case emphasizes the possibilities of cytology for the diagnosis of mycotic infections. Fungi have typical morphologies, and it is possible, on the basis of microscopic evidence, to suspect the nature of the infection early and thus to direct culture procedures.

AIDS-Related Opportunistic Infections↗
PubMed2002

The SOD2 gene, encoding a manganese-type superoxide dismutase, is up-regulated during conidiogenesis in the plant-pathogenic fungus Colletotrichum graminicola.

The SOD2 gene, encoding a manganese-type superoxide dismutase (MnSOD), was identified from Colletotrichum graminicola among a collection of cDNAs representing genes that are up-regulated during conidiogenesis. The SOD2 gene consists of a 797-bp open reading frame that is interrupted by three introns and is predicted to encode a polypeptide of 208 amino acids. All conserved residues of the MnSOD protein family, including four consensus metal binding domains, are present in the predicted SOD2 protein. However, the predicted protein does not appear to contain a signal peptide that would target it to the mitochondria. Northern hybridizations revealed that expression of the approximately 900-bp SOD2 transcript is closely associated with differentiation of both oval and falcate conidia. Southern analysis indicated that there is only a single copy of the gene. SOD2 disruption strains were morphologically and pathogenically indistinguishable from wild-type strains. The dispensability of the MnSOD enzyme may be due to the activities of two other SOD enzymes, a highly expressed iron-type superoxide dismutase and a much less abundant copper/zinc type, that were also detected in C. graminicola.

Amino Acid Sequence↗
PubMed2004

Polykaryon formation using a swollen conidium of Trichoderma reesei.

The cellulolytic fungus, Trichoderma has oval and mononucleate conidia. When these conidia are incubated in a liquid medium, they begin to swell and their shape becomes spherical followed by an increase in inner space. In such swollen conidia, it is possible to produce a larger autopolyploid nucleus using a mitotic arrester compared with the case of the original conidia. In this study, polykaryon formation was attempted using these swollen conidia. Dried mature green conidia of Trichoderma reesei QM6a (IFO 31326) were incubated in Mandel's medium in order to swell. The swollen conidia were treated with a mitotic arrester, colchicine, for autopolyploidization. After autopolyploidization, polykaryon formation was carried out using the swollen conidia. After the treatment, multiple smaller nuclei whose diameter was almost the same as that of the original strain were generated from an autopolyploid nucleus in a swollen conidium. A cellulase hyperproducer without decrease in growth rate could be selected using such swollen conidia.

Biotechnology↗
PubMed1996

Cancer is a hybrid produced by a relationship between a plant bacterium and a mammalian cell: an original concept.

Facts presented in previously published articles (1-7) support the conclusion that the malignant cell, although of animal origin, metabolizes and respires anaerobically. Facts also support the conclusion that plant bacterial conidia (spores) derived, under duress, from one of the several groups belonging to the Ascomycete family or from the Staphylococcus aureus coagulase positive micro-organism are present intracellularly. It is this group of conidia, when formed, that survives as a primitive oval, spheroidal type of a unicell. They are identical in all respects to the various carbohydrate, protein, and fat molecules. Although these conidia have lost their original outside cell wall and all their enzymes and metabolites, they survive none the less as bacteria by retaining within their cytoplasm a genetically viable anion acceptor complex (oxidant), and their asexual procreative unit. It is this oxidant factor that survives within a sac or cell, as long as it is free of the atmospheric environment. Ultimately, with an ensuing circulating but compatible flow of blood by the host, there develops an annealing process whereby the genes of each species unite to form a plant animal intracellular hybridization. This somatic association accounts for the origin of the metabolic and respiratory anaerobiosis and also for the subsequent growth and pathophysiology that occurs in those living human beings suffering from the various malignant diseases.

Anaerobiosis↗
PubMed1992

Morphological variation in pathogenic strains of Penicillium marneffei.

Penicillium marneffei is a dimorphic fungus known to be pathogenic to animals and man. The natural reservoir of this organism was known to be bamboo rats found in South Vietnam, Thailand and China. The first two human infections were reported in 1959 and 1973 from the United States. Up to 1984, five new cases of human penicillosis were reported from Thailand. Since then several more cases have been reported from different parts of the world mainly from the southern part of China. However, there are very limited mycological descriptions of this fungi. In this report, five Thai strains were studied for colonial morphology in comparison with Reference strain PLM 689. Variation in mycelial pigment was observed ranging from yellowish-green to orange with water soluble red pigment produced in every strain which can be seen early from the reverse side. Ultrastructural study by both scanning electron microscopy (SEM) and transmission electron microscopy (TEM) was compared with that of the reference strain PLM 689. PLM 689 strain had only biverticillate penicilli, but all five strains from Thailand had both monoverticillate and biverticillate penicilli which occasionally appeared on the same branch. The conidia of the Thai isolates were oval in shape and 1.3-2 x 0.7-1.6 microns in size smaller than those of PLM 689 which were 2.5-4 x 2-3 microns. Phialides were also smaller and a little shorter but the number of phialides was similar to those of PLM 689 ranging 4-10 except for one strain which had 3-16 phialides. All Thai strains have stipes smaller and somewhat longer than those of PLM 689.(ABSTRACT TRUNCATED AT 250 WORDS)

Hospitals, University↗
PubMed2000

Are giant cells conidia in Sporothrix schenckii? -Freeze-fracture electron microscopic observation-.

Sporothrix schenckii is a well-known pathogenic dimorphic fungus. In this study, we focused on the plasma membrane ultrastructures of giant cells of S. schenckii seen mainly on Sabouraud's dextroseagar slant medium. In the organisms grown for 1, 2, 3, 4, 6 and 8 weeks at 27 and 37 degrees C on brain heart infusion and Sabouraud's dextrose agar slant media, the number of conidia, hyphae, brownish and non-brownish giant cells were counted in ten separated areas under light microscope (x100) to determine the culture conditions under which giant cells were generated. The results showed that brownish giant cells were predominantly seen after longer cultivation periods. Using freeze-fracture electron microscopy, larger oval- or round shaped cells can be identified as conidia by their plasma membrane ultrastructure characteristics, i.e, trench-like invaginations seen in ordinary mature conidia (Maeda M et al.; Can J Microbiol 33: 40, 1987). From these structural features seen by freeze-fracture electron microscopy, giant cells appeared possibly be conidia and were suggested to be starved because of their predominant existence under longer cultivation conditions.

Freeze Fracturing↗
PubMed1977

The relationship between conidiation and alkaloid production in saprophytic strains of Claviceps purpurea.

A direct relationship between alkaloid synthesis and conidia formation was observed in a series of mutants of the saprophytic fungus Claviceps purpurea 129 which produces high quantities of clavine alkaloids (4500 microgram-ml-1). Sclerotia-like mutants forming mostly arthrospores and only a low number of conidiospores were exceptional in that they were characterized by an inverse relationship between alkaloid synthesis and conidial formation. Conidiospores of the parent strain 129 differed both in their size and ultrastructure. They include oval microconidia (2 X 3.5 micrometer) and prolonged macroconidia (2 X 10.5 micrometer). Both conidial types originated on short lateral sporophores terminated by phialids. Most conidia were characterized by electron-dense cytoplasm with a number of lipidic inclusions; a minority of conidia contained granular cytoplasm and vacuoles with membrane invaginations. Bicellular conidia were only rarely observed.

Claviceps↗
PubMed1975

Ultrastructural and electron cytochemical studies of Entomophthora coronata.

Aspects of the fine structure as well as electron cytochemical localization studies of certain hydrolytic enzymes were examined by electron microscopy of ultrathin sections of the vegatative hyphae and conidia of the phycomycetous fungus, Entomophthora coronata. This entomogenous fungal organism is of interest since it has been increasingly implicated as the etiologic agent of phycomycosis of man and animals. On thin section, hyphal cells were frequently observed with septa while the cytoplasm was multinucleate. The conidium was bound by a multilayered cell wall. The cytoplasm of ungerminated conidia characteristically contained large numbers of a class of cytoplasmic organelle found in loose aggregates with lipid storage bodies. Similar organelles were observed in the cytoplasm of hyphal cells from 7-day old cultures. This round to oval to slightly reniform structure was bound by a single limiting membrane and composed of an electron dense, slightly granular matrix without evidence of crystalloid formation. The limiting membrane of the lipid storage bodies was observed to be intimately associated with that of one or more of these microbody-like organelles. This intimate association of the two cytoplasmic organelles suggests that the microbody-like organelle may be involved in some manner with lipid metabolism during the life cycle of the fungus. Cautious interpretations of electron cytochemical localization studies suggested that lipase, nonspecific esterase, and possibly aryl sulfatase were associated with the microbody-like organelles. Neither peroxidatic nor acid phosphatase activity could be demonstrated with these organelles of the conidial cytoplasm.

Arylsulfatases↗
PubMed2000

White grain mycetoma caused by a Cylindrocarpon sp. in India.

We describe a case of white grain eumycetoma of the foot of an Indian male caused by a slow-growing, poorly sporulating fungus that does not match any known agent of this infection. Histologic examination of a biopsy tissue specimen showed oval, lobular, white granules composed of hyaline, septate hyphae, and thick-walled chlamydospores. Culture of granules from a draining sinus yielded compact, very-slow-growing, poorly sporulating colonies producing a strong reddish brown pigment that diffused into the medium. The fungus was identified as a Cylindrocarpon sp. based on the development of rare cylindrical conidia borne from solitary phialides lacking collarettes, in addition to chlamydospores formed singly or in short chains.

Foot Dermatoses↗
PubMed2006

Emmonsia crescens infection in a British water vole (Arvicola terrestris).

Emmonsia crescens, a dimorphic fungus of the order Onygenales, is primarily a pathogen of lower animals and rarely humans. Inhaled conidia of E. crescens fail to germinate in the lungs, and instead simply enlarge in lung tissue to become giant adiaspores. We present here the case of fatal Emmonsia crescens infection in a wild-caught British water vole (Arvicola terrestris). Histopathological examination of the animal, which died in captivity, revealed a multifocally extensive granulomatous reaction containing oval adiaspores scattered irregularly throughout the lungs. Mycological examination of fungus cultured from lung tissue and PCR amplification and sequencing of rDNA gene fragments of the cultured organism confirmed the diagnosis of massive infection by E. crescens.

Animals↗
PubMed1988

Subcutaneous phaeohyphomycosis caused by Xylohypha emmonsii.

The first human phaeohyphomycotic infection caused by Xylohypha emmonsii is described. The patient, an 83-year-old woman, developed a purpuric lesion on her left arm. The pale brown fungal elements observed in biopsy tissue consisted of thin- to thick-walled, oval to spherical, yeastlike cells with single and, occasionally, multiple buds; chains of budding cells; cells with internal septations in one and, rarely, two planes; and septate hyphae. In culture, X. emmonsii grew moderately fast at 25 degrees C, showed minimal growth at 37 degrees C, and failed to grow at 40 degrees C. It produced acropetal chains of one-celled (rarely two-celled) conidia laterally and terminally directly from vegetative hyphal cells.

Aged↗
PubMed1987

Freeze-fracture electron microscopic studies of age-related plasma membrane changes in Sporothrix schenckii.

Characteristics of the plasma membrane of Sporothrix scheckii cells as revealed by freeze-fracture techniques have been classified into eight types (Y1, Y2a, Y2b, Y3a, Y3b, Y4a, Y4b, and Y5) in yeastlike cells grown under the following two conditions: brain heart infusion agar medium at 27 degrees C, and brain heart infusion agar medium at 37 degrees C. Type Y1 cells are yeastlike cells having smooth plasma membranes without any invagination. Typical characteristics of the other types are as follows: type Y2a, smooth plasma membranes with few trenchlike invaginations; type Y2b, wavy plasma membranes with few oval or irregularly formed invaginations; type Y3a, plasma membranes with many randomly distributed trenchlike invaginations; type Y3b, plasma membranes with many cocoonlike or irregularly formed invaginations; type Y4a, plasma membranes with longer trenchlike invaginations; type Y4b, plasma membranes with irregularly formed, enlarged invaginations; and type Y5, smooth or wavy plasma membranes with aggregations of intramembranous particles and with many vacuoles between cell walls and plasma membranes or in the cytoplasm in some cells. By counting the proportion of each type of yeastlike cell under the two conditions and with different cultivation periods, it appears that plasma membrane types change as aging progresses in the following order: type Y1, Y2a, Y3a, Y4a, and Y5 in conidia and type Y1, Y2b, Y3b, Y4b, and Y5 in yeastlike vegetative cells. These observations provide us with an important advantage when studying the effects of antifungal agents on the plasma membrane of Sporothrix scheckii, as it is important to know the natural course of changes in membrane structure during aging.

Cell Membrane↗