Mitochondrial DNA organisation of the mtDNA type 2b of Aspergillus tubingensis compared to the Aspergillus niger mtDNA type 1a.

A physical and functional map of Aspergillus tubingensis mtDNA type 2b was constructed and compared to Aspergillus niger typeI a mtDNA. The gene content and order, as well as the patterns of restriction sites, were similar. Two unidentified ORFs and several repeat elements were found in the region between the ndhl and ndh4 genes on both mtDNAs.

Production of extracellular proteases by human pathogenic Trichoderma longibrachiatum strains.

Species belonging to the filamentous fungal genus Trichoderma are well known as potential candidates for the biological control of plant pathogenic fungi and as cellulase producers of biotechnological importance. Several data were published in the last decade also about the clinical importance of this genus, indicating that Trichoderma strains may be potential opportunistic pathogens in immunocompromised patients. However, there is a lack of information about the potential virulence factors of clinical Trichoderma strains.

Isolation and characterization of protease overproducing mutants of Trichoderma harzianum.

Several Trichoderma strains have been reported to be effective in controlling plant diseases, and the action of fungal hydrolytic enzymes is considered as the main mechanism involved in the antagonistic process. Strain Trichoderma harzianum T334 is a potential biocontrol agent against plant pathogenic fungi with the ability to produce low levels of proteases constitutively. To improve its fungal antagonistic capacity, mutagenetic program was undertaken for the construction of protease overproducing derivates.

In vitro water activity and pH dependence of mycelial growth and extracellular enzyme activities of Trichoderma strains with biocontrol potential.

Aims: Water activity (aw) and pH are probably the most important environmental parameters affecting the activities of mycoparasitic Trichoderma strains. Therefore it is important to collect information on the effects of these factors on mycelial growth and on the in vitro activities of extracellular enzymes involved in nutrient competition (e.g.

Clinical importance of the genus Trichoderma. A review.

Opportunistic fungal infections have been observed with increasing frequency in recent years in immunocompromised patients. Several data were published in the last decade about the clinical importance of the filamentous fungal genus Trichoderma, indicating that Trichoderma strains--besides their agricultural and biotechnological importance--may be potential opportunistic pathogens in immunocompromised hosts as well. This review is going to summarize the clinical case reports about Trichoderma infections, and to discuss the information available on the antifungal susceptibility and on the ecophysiological, enzymological and systematic aspects of clinical Trichoderma isolates.

Genetic diversity in the red yeast Cryptococcus hungaricus and its phylogenetic relationship to some related basidiomycetous yeasts.

Cryptococcus hungaricus is a basidiomycetous yeast with the abilities to synthesize carotenoid pigments and to grow under psychrophile conditions. Six C. hungaricus strains have been isolated so far from different habitats.

Interpretation of intraspecific variability in mtDNAs of Aspergillus niger strains and rearrangement of their mtDNAs following mitochondrial transmissions.

Physical and functional maps of mitochondrial DNAs of Aspergillus niger strains representing different mitochondrial DNA RFLP patterns were constructed and compared. In spite of the high similarity in the organisation of mitochondrial DNAs among examined strains, differences could be easily recognised by applying molecular markers, such as the different intron content of the cox1 genes, the sequence of the intergenic regions between the Met- and His-tRNA genes and downstream of the tRNA-Gly gene. Intraspecific mitochondrial transfers between the heterokaryon incompatible mitochondrial oligomycin-resistant A.

Organization of mitochondrial DNA in the basidiomycetous Dioszegia hungarica (Cryptococcus hungaricus) species.

The organization of mitochondrial DNA was investigated in the six collection strains of the basidiomycetous yeast Dioszegia hungarica (Cryptococcus hungaricus) isolated so far. Physical and partial functional maps were constructed. Two strains (CBS 6324 and 6576) were identical while three others (CBS 4214, 5124, 6953) differed not only in the distribution of restriction sites but in gene order as well.

Complete DNA sequence and analysis of a mitochondrial plasmid in the mycoparasitic Trichoderma harzianum strain T95.

A circular plasmid called pThr1, with a monomer size of 2.6 kb, was identified in the mitochondria of a Trichoderma harzianum isolate. Hybridization studies using cloned plasmids revealed no DNA sequence similarity between the plasmid and the mitochondrial genome of the isolate.

Intra-strain variability of Cryptococcus neoformans can be detected on phloxin B medium.

A method was devised for easy detection of intra-strain variability of the human pathogenic yeast Cryptococcus neoformans. Cultivation of strains on a medium containing Phloxin B resulted in different coloured colonies. Generally, colonies were either pink or red; however there were also several colony-colour segregant in which both colours could be observed.

Secretion of a trypsin-like thiol protease by a new keratinolytic strain of Bacillus licheniformis.

When cultured in feather-containing broth with a growth optimum of pH 7.0 and 47 degrees C, a Bacillus licheniformis strain exhibited a high chicken feather-degrading activity. A trypsin-like protease was isolated from its ferment broth and was partially characterized.

Intron mobility results in rearrangement in mitochondrial DNAs of heterokaryon incompatible Aspergillus japonicus strains after protoplast fusion.

Mitochondrial transmission was carried out under selective conditions between incompatible Aspergillus japonicus strains always using an oligomycin-resistant mitochondrial donor and selecting for recipient nuclei and oligomycin-resistant mitochondria. All attempted intraspecific mitochondrial transmissions were successful, but the transmission between closely related A. japonicus and A.

Interaction between mitochondria derived from incompatible black Aspergillus isolates.

As black Aspergillus isolates are highly heterokaryon-incompatible mitochondrial transmissions were performed by protoplast fusion. Donor strains with oligomycin-resistant mitochondria and sensitive recipient partners of various A. japonicus isolates were applied and the progeny were selected for oligomycin resistance and for recipient nuclear phenotype.

Interpretation of variability of mitochondrial genomes in the species Aspergillus carbonarius.

For interpretation of intraspecific polymorphism and the considerable differences in the size of mtDNAs among three groups of A. carbonarius, restriction maps were constructed from several enzymes. Functional maps were also developed to compare genome organisations and gene content.

Recombination of mitochondrial DNA without selection pressure among compatible strains of the Aspergillus niger species aggregate.

Previous mitochondrial transmission experiments between oligomycin-resistant and oligomycin-sensitive incompatible strains of the A. niger aggregate bearing various mtDNA RFLP profiles resulted in a great variety of mitochondrial recombinants under selection pressure. Apart from the recombinant mtDNAs, resistant clones harbouring unchanged RFLP profiles of resistant donor mtDNAs with the recipient nuclear backgrounds were rarely isolated.

Molecular and phenotypic characterization of Aspergillus japonicus and Aspergillus aculeatus strains with special regard to their mitochondrial DNA polymorphisms.

Forty Aspergillus japonicus and A. aculeatus strains, most of them wild-type isolates, were examined using various molecular and phenotypic techniques. The rDNAs proved to be invariable (even strains of the species A.

Recombination of mitochondrial DNAs following transmission of mitochondria among incompatible strains of black Aspergilli.

Successful intra- and interspecific mitochondrial transfers were performed by polyethylene glycol (PEG)-induced protoplast fusion among incompatible strains belonging to the Aspergillus niger species aggregate. The mitochondrial DNAs (mtDNAs) of the strains examined were of three main types based on their restriction fragment length polymorphism (RFLP) profiles. mtDNA types 1 and 2 correspond to A.

Factors affecting the spread of double-stranded RNA viruses in Aspergillus nidulans.

Viruses are common in asexual Aspergilli but not in sexual Aspergilli. We found no viruses in 112 isolates of the sexual Aspergillus nidulans. We have investigated factors that could play a role in preventing the spread of mycoviruses through populations of A.

Molecular polymorphism and phenotypic variation in Aspergillus carbonarius.

Thirteen collection strains and field isolates of Aspergillus carbonarius were examined by using various genotypic and phenotypic approaches. Restriction fragment length polymorphism analysis of the ribosomal RNA gene cluster and the mitochondrial DNA of the strains revealed only slight variations, except for one field isolate (IN7), which exhibited completely different ribosomal RNA gene cluster and mitochondrial DNA patterns. The mitochondrial DNAs of these strains were found to be much larger (45 to 57 kb) than those found earlier in the A.

Immunochemical detection of ochratoxin A in black Aspergillus strains.

One hundred and fifty-seven strains belonging to Aspergillus section Nigri were tested for ochratoxin A production using three different methods: a relatively new immunochemical method based on an enzyme-linked immunosorbent assay (ELISA), thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). The monoclonal antibody-based ELISA technique was successfully used to screen for low levels of ochratoxin A in the black Aspergilli without concentrating the culture filtrates. The results were confirmed by TLC and HPLC analysis and chemical derivatization.

Mitochondrial DNA restriction fragment length polymorphisms in field isolates of the Aspergillus niger aggregate.

The mitochondrial DNAs (mtDNAs) and the ribosomal repeat unit (ribosomal DNA, rDNA) of black Aspergillus isolates collected in various parts of the world were examined. Wide-ranging mtDNA variation was observed in natural populations of the Aspergillus niger aggregate. Most isolates were classifiable as A.

Double-stranded RNA mycoviruses in section Nigri of the Aspergillus genus.

Double-stranded RNA bands were detected electrophoretically in about 7% of natural isolates and in 13 of 51 collection strains belonging in section Nigri of the genus Aspergillus. The identity of these bands was proved by S1 nuclease and RNase treatment. Most of the virus-containing natural isolates came from Indonesia.