Large Hyphae Research Articles

Notoparmelia, a new genus ofParmeliaceae(Ascomycota) based on overlooked reproductive anatomical features, phylogeny and distribution pattern

AbstractThe importance of the anatomy and fine morphology of reproductive structures for the systematics of the familyParmeliaceaeis highlighted by the new genusNotoparmelia, described here for Australasian species ofParmelia. These species were known to form a monophyletic lineage but correlated characters for its delimitation were lacking. A major characteristic used here for the circumscription of this genus is the overlooked apothecial anatomy. The proper exciple is reduced to one layer formed exclusively by large hyphae without any clear branching pattern and embedded in an abundant polysaccharide matrix. This feature differs from the rest ofParmeliaceaewhich have a stratified three-layered proper exciple composed of a thin hyaline layer, intermediate layer and basal cortex-like structure. The anatomy of proper exciple, together with the thickness of spore walls and other morphological characters such as lobe morphology, pseudocyphellae and rhizine type, allow a precise diagnosis of the new genus. The area of distribution is also useful for characterizing this genus. Sixteen new combinations are proposed.

A fatal pseudo-tumour: disseminated basidiobolomycosis

BackgroundBasidiobolomycosis is a rare disease caused by the fungus Basidiobolus ranarum, member of the class Zygomycetes, order Entomophthorales, found worldwide. Usually basidiobolomycosis is a subcutaneous infection but rarely gastrointestinal manifestations have been described; 13 adults and 10 children and a few retroperitoneal or pulmonary cases. In gastrointestinal basidiobolomycosis the colon is most frequently involved, usually presenting with subacute mild abdominal pain. In contrast to children only very few described adult patients had hepatic masses. Definitive diagnosis requires culture, serological testing can be helpful. The fungal morphology and the Splendore-Hoeppli phenomenon are characteristic histological features. There are no prominent risk factors. Usually surgery and prolonged antifungal therapy are required.Case presentationA 61 year old man presented with progressive left abdominal pain and constipation since a few months. Colonoscopy showed an obstructing tumour in the descending colon, and a hemicolectomy was performed. Histology showed inflammation, possibly caused by a fungal or parasitic infection, without definite identification of an organism. A few weeks postoperatively a CT scan made because of abdominal discomfort, revealed a livermass (6 cm). Treatment with metronidazole, directed against an amoebic liver abscess, was unsuccessful. He developed a marked eosinophilia (27.7%). A liver biopsy was performed and the patient was referred to a university hospital.A repeated CT scan showed a livermass of 9 cm diameter. Review of colon and liver biopsy samples showed extensive necrosis and histiocytes, multinucleated giant cells and numerous eosinophils. Grocott stained sections contained unusually large hyphae surrounded by strongly eosinophilic material in haematoxylin and eosin stained sections (Splendore-Hoeppli phenomenon). A presumptive diagnosis of Basidiobolus spp. infection was made and treated with amphotericin B (Itraconazol contra-indicated because of renal insufficiency). A few days later the patient died of a septic shock. After autopsy Basidiobolus ranarum was cultured from liver, gallbladder and colon.ConclusionOur patient died of gastrointestinal basidiobolomycosis with an obstructing colon tumour and a large hepatic mass. This was a rare presentation of basidiobolomycosis and the second fatal case described worldwide.

A highly differentiated glomeromycotean association with the mucilage‐secreting, primitive antipodean liverwort Treubia (Treubiaceae): clues to the origins of mycorrhizas

Thallus anatomy in three species of the primitive liverwort genus Treubia (Metzgeriidae, Treubiales) was studied by light and electron microscopy. The thallus exudes copious mucilage, a feature shared elsewhere in liverworts only with the mycotrophic subterranean axes of the allied genus Haplomitrium. The central strand in the thallus midrib has a unique histological organization and harbors an intra- and intercellular infection by a glomeromycotean fungus that is far more highly differentiated than most of the glomeromycotean associations described to date. The fungus enters the thallus via clefts in the ventral epidermis along the midrib and colonizes the parenchyma above, forming intracellular coils and prominent, relatively short-lived, hyphal swellings. Above the zone with intracellular colonization is a tissue area containing mucilage-filled intercellular spaces; here the fungus is entirely intercellular and forms abundant pseudoparenchymatous structures and, in more mature parts of the thalli, large hyphae with thick multistratose walls. Mucilage in Treubia differs in histochemistry and origin from that produced by apical papillae, via hypertrophied Golgi, in all other bryophytes. Remarkable parallels between fungal associations in Treubia, Haplomitrium, and Lycopodium, all members of very ancient lineages, suggest that these associations epitomize very early stages in the evolution of glomeromycotean symbioses.

Two members of the Glomeromycota form distinct ectendomycorrhizas with Alzatea verticillata, a prominent tree in the mountain rain forest of southern Ecuador

Mycorrhizas formed by members of the Glomeromycota with roots of Alzatea verticillata (Alzateaceae, Malpighiales), a characteristic tree of the neotropical mountain rain forest in southern Ecuador, were investigated using light microscopy. Two morphotypes are described. One morphotype forms very fine, fan-shaped branches in the intercellular space of the inner cortical layer. The fungus most probably belongs to the so-called fine endophytes. A second morphotype was distinguished by its larger hyphae and intercellular, ctenoid branches. In both morphotypes, arbuscules were formed, but vesicles and intraradical spores were lacking. The results show, for the first time, arbuscular mycorrhizas with abundant intercellular, finger-like branches resembling appressoria and reminiscent of the Hartig net structure in ectomycorrhizas. The Hartig net is known as a place for nutrient exchange and a similar function is presumed here. Consequently, the described morphotypes should be classified as ectendomycorrhizas. The presented results are also a contribution for distinguishing members of Glomeromycota by their vegetative structures.

Microtubules of the mycorrhizal fungus Glomus intraradices in symbiosis with tomato roots

In this study the presence and orientation of fungal microtubules were recorded in arbuscular mycorrhizal symbiosis for the first time. Visualization of the fungal microtubules was achieved by using a protocol specifically labelling only fungal tubulins. Microtubules of external mycelium, intraradical hyphae, arbuscules, and vesicles of the arbuscular mycorrhizal fungus Glomus intraradices Schenck & Smith were examined when in symbiosis with tomato (Lycopersicon esculentum Mill.). Microtubules were organized as bundles in both external and intraradical hyphae. The bundles of microtubules extended directly from intraradical hyphae into the arbuscules, where the microtubules remained as bundles in the larger hyphae. In the fine fungal branches of the arbuscules, microtubules were seen as thinner filaments. Fungal microtubules were seen to connect the intraradical hyphae and arbuscules. In addition, microtubules of adjacent arbuscules could continue directly from one arbuscule to another. Microtubules reached to the basal cone of each vesicle, but the live vesicles, containing many nuclei, seemed devoid of any microtubular labelling.Key words: cytoskeleton, endomycorrhiza, filamentous fungi, tomato, tubulin, Zygomycota.

Unusual structures of Sporothrix schenckii.

A series of environmental and clinical isolates of Sporothrix schenckii being studied in our laboratories under standard conditions of temperature, humidity and media, displayed, in some of the isolates, large dematiaceous hyphae. The large hyphae could be seen to produce the fine hyphae associated with S. schenckii on which typical microconidia developed. Typical microconidia also developed occasionally on the large hyphae, and strands of the unusually large hyphae also were seen to form arthroconidia. Some strains formed large, thin-walled cells on thin and/or thick hyphae resembling the 'balloon cells' seen in mature colonies of Trichophyton tonsurans. All strains which have demonstrated these various and unusual structures histopathologically produced typical sporotrichosis in laboratory animals. When reisolated from these animals, the cultures again exhibited the unusual structures, as well as those typical of S. schenckii.

NOTES ON THE CYTOLOGY AND SEXUALITY OF PUFFBALLS.

In stained squash preparations of young puffballs, the subterminal cells are binucleate. Prophase I of young basidia is too indistinct for details, but metaphase and anaphase I reveal the chromosomes and suggest that their number is n = 3 in Lycoperdon pusillum and Calvatia gigantea, and n = 4 in L. pyriforme and L. curtisii. Each mature basidium contains a tetrad. The basidiospore contains two (sister) nuclei. Hyphae of the species investigated are smooth, lacking clamp connections. Their cells are usually binucleate, but the nuclei are not closely associated in pairs. Such species may be haploid. In a variant of C. gigantea the tissue is made up of much larger hyphae, possessing clamp connections and each cell containing a pair of very large nuclei. The variant is therefore diploid. More of such tissue should be sought.