Intrahyphal Hyphae in the Basidiomycete, Gloeophyllum (Lenzites) Saepiarium

Hyphal healing mechanism in the arbuscular mycorrhizal fungi Scutellospora reticulata and Glomus clarum differs in response to severe physical stress

The hyphal healing mechanism (HHM) has been shown to differ between Gigasporaceae and Glomeraceae. However, this process has not been considered under (severe) physical stress conditions. Scutellospora reticulata and Glomus clarum strains were cultured monoxenically. The impact of long distance separating cut extremities of hyphae and of multiple injuries within hyphae on the HHM was monitored. For long distances (>5000 microm) separating cut extremities, hyphae healing was observed in half the cases in S. reticulata and was absent in G. clarum. For multiple-injured hyphae, the HHM was always oriented towards the complete recovery of hyphae integrity in S. reticulata, while in G. clarum, the growing hyphal tips (GHTs) could indifferently reconnect cut sections, by-pass cut sections or develop into the environment. Hyphae behaviour under severe physical stress clearly differentiated S. reticulata from G. clarum, suggesting that both fungi have developed different strategies for colony growth to survive under adverse conditions.

Ultrastructural and Immunocytochemical Studies on the H 2 O 2 -Producing Enzyme Pyranose Oxidase in Phanerochaete chrysosporium Grown under Liquid Culture Conditions

The ultrastructural distribution of the sugar-oxidizing enzyme pyranose 2-oxidase (POD) in hyphae of Phanerochaete chrysosporium K-3 grown under liquid culture conditions optimal for the enzyme's production was studied by transmission electron microscopy immunocytochemistry. Using the 3-dimethylaminobenzoic acid-3-methyl-2-benzothiazolinone hydrazone hydrochloride H 2 O 2 peroxidase spectrophotometric assay, POD was detected in mycelial extracts from days 7 to 18, with maximum activity recorded on day 12. Onset of POD activity occurred in the secondary phase of hyphal development at a time of stationary growth, glucose limitation, and pH increase. POD was also detected extracellularly in the culture fluid from days 7 to 18, with maximum activity recorded on day 13. At early stages of development (3 to 4 days), using anti-POD antibodies and immunogold labeling, POD was localized in multivesicular and electron-dense bodies and in cell membrane regions. After 10 to 12 days of growth, at maximum POD activity, POD was concentrated within the periplasmic space where it was associated with membrane-bound vesicles and other membrane structures. At later stages of development (17 to 18 days), when the majority of hyphae were lysed, POD was observed associated with residual intracellular membrane systems and vesicles. Transmission electron microscopy immunocytochemical studies also demonstrated an extracellular distribution of the enzyme at the stationary growth phase, showing its association with fungal extracellular slime. In studies of ligninolytic cultures of the same fungus, POD was found to have a similar intracellular and extracellular distribution in slime as that recorded for cultures grown with cornsteep. POD's peripheral cytoplasmic distribution shows similarities to the cellular distribution of that reported previously for H 2 O 2 -dependent lignin and manganese peroxidases in P. chrysosporium.

Cerebral Paecilomyces javanicus infection. An ultrastructural study

A 41-year-old diabetic woman developed Paecilomyces javanicus endocarditis and subsequent cerebral fungal embolism and vasculitis with massive infarction and hemorrhage 6 years after a mitral valve replacement with porcine heterograft. The organism was identified by the culture from the infected brain tissue and aortic valve. Cerebral infection due to fungus Paecilomyces is rare. This report documents the cerebral manifestations of fungus Paecilomyces javanicus and describes for the first time the ultrastructure of such an organism obtained from the infected tissue. Their ultrastructural findings, similar to those described in Paecilomyces farinosus derived from culture, include a double-layered cell wall, a triple unit plasma membrane, abundant cytoplasmic lipid droplets, vacuoles, membranous profiles and septal formation. This report further demonstrates hyphae with packed 50A filaments and granulofibrillary material and features suggestive of intrahyphal hyphae, not previously described in fungus Paecilomyces.

Origin and ultrastructure of intra-hyphal hyphae in Trichophyton terrestre and T. rubrum

A cell observation chamber was designed to perform continuous photomicroscopic observations of hyphal anastomosis and the origin of intra-hyphal hyphae in Trichophyton terrestre and T. rubrum. These data were correlated with ultrastructural features of intra-hyphal hyphae. Hyphal fusions occurred commonly in either species of Trichophyton when incubated alone. In T. terrestre, empty phyphal segments adjoined by live units were invaded at the septa from both directions by new hyphal ingrowth. Continuous observations revealed that the intra-hyphal hyphae subsequently anastomosed via a lateral fusion peg. Similar intra-hyphal hyphae were shown in T. rubrum. Electron microscopic studies revealed ascomycetous septa in both conventional hyphae and intra-hyphal hyphae. For the latter, the cytoplasm and wall of the inner hypha were bounded by cytoplasmic organelles and another cell wall of the outer hypha.