Fungal dimorphism is a complex trait and our understanding of the ability of fungi to display different growth morphologies is limited to a small number of model species. Here we study a highly aggressive dimorphic fungus, the ascomycete Ophiostoma novo-ulmi, which is a model in plant pathology and the causal agent of Dutch elm disease. The two growth phases that this fungus displays, i.e., a y...

The health condition of the population of elms in the region of southern Bohemia was studied from the viewpoint of their decline, the occurrence of Dutch Elm Disease (DED) and the presence of other diseases. Of the total number of 105 elms in total 33 of them were without any symptoms of the disease or other damage. Elms regenerated quite spontaneously in the neighbourhood of mother trees and t...

Despite our increasing recognition of the key role that microbes play in ecosystem processes (e.g., Giller et al. 1997; Mills and Bever 1998; van der Heijden et al. 1998), concern over the loss of biodiversity in ecological communities rarely focuses on microbes— particularly pathogenic microbes which are more often targeted for eradication than preservation (but see Windsor 1995). Yet it is be...

The yeast-mycelium dimorphism in Ceratocystis ulmi, the causative agent of Dutch elm disease, was switched by gossypol, nordihydroguaiaretic acid, and propylgallate. In each case the mycelial form was converted to the yeast form. These compounds are recognized lipoxygenase inhibitors. Inhibitors of cyclooxygenase and thromboxane synthetase did not cause mycelia to shift to the yeast form. We su...

Cutaneous delayed hypersensitivity to antigens prepared from Sporothrix schenckii and several Ceratocystis species, including C. stenoceras, C. ulmi, C. ips, and C. minor, was tested in 14 patients with known cutaneous sporotrichosis. Extensive cross-reactions were observed. Nonsporotrichotic people (controls) did not react to these antigens. The correlation coefficient between antigens of S. s...

dutch elm disease is one of the most destructive vascular wilt diseases in the world. ophiosatoma ulmi and o. novo-ulmi had been the most important causal agents of the dutch elm disease in the last century. so, in order to manage of disease, their identification and distinction is necessary. these fungal species were distinguished based on morphological, physiological and molecular characters....

In this study, four specimens belonging to Karaj mycoflora were examined. According to the results, two form – species; Diplosporonema delastrei, on Silene latifolia subsp. persica and Piggotia ulmi, on Ulmus sp. are reported with new names. For some of the identified fungal specimens, new hosts (matrix nova) are introduced. Moreover, many taxa such as , Marssonina kriegeriana on Salix sp.,  Se...