The suitability of randomly amplified polymorphic DNAs (RAPD) for differentiation at the varietal and intravarietal level was tested on several hundred isolates of the gaeumannomyces‐Phialophora (G‐P) complex from different geographic locations and host plants. Amplification products obtained using two decamer primers allowed differentiation between gaeumannomyces graminis and gaeumannomyces cylindrosporus and between the three varieties of gaeumannomyces graminis, as well as further division at the intravarietal level. Thus, isolates of the causal agent of take‐all on cereals, Gaeumannomyces graminis var. tritici were divided into six subgroups by amplification with these two primers. There is some evidence for an association between host preference and RAPD subgroups but further work is needed to confirm this and to determine the importance of these subgroups. This fast and easy method is a useful tool for investigating the occurrence and distribution of this pathogen and for studying changes in the populations of species and subgroups of Gaeumannomyces in cereal cropping systems

A new group of darkly pigmented root-infecting fungi was isolated from cereal roots obtained from six different locations in northeastern Germany. Similar random amplified polymorphic DNA (RAPD) patterns and restriction profiles of amplified rDNA were used as a basis for classifying the isolates in a separate group. The isolates demonstrating mycelial and infection characteristics typical of Gaeumannomyces graminis could be differentiated from the varieties of G. graminis as well as from Gaeumannomyces cylindrosporus\Phialophora graminicola using RAPD Polymerase chain reaction (PCR) and rDNA Restriction-fragment length polymorphism (RFLP) analysis. Phylogenetic analysis of the Internal transcribed spacer (ITS) regions suggests that the isolates form a distinct group (named group ' E') situated within the Gaeumannomyces-Phialophora complex between the branch of the G. graminis varieties and Gaeumannomyces incrustans\Magnaporthe poae. Isolates of group E produced lobed hyphopodia and were shown in biotests to be non-pathogenic to wheat, oats, Italian Ryegrass and Chewings Fescue, suggesting it is a benign parasite which colonizes cereals or grasses without destroying vascular tissue. Furthermore, curved phialospores could be found. Summarizing the results presented, this new group could be classified as a new species of Phialophora. Although isolates of group E were found at only six of the 32 investigated locations, they composed up to 50% of total isolates of the Gaeumannomyces-Phialophora complex at these sites. Because of the non-pathogenic behaviour, the new group may be of value as biological control agents for pathogenic fungi.

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Freshly prepared dentine specimens of human teeth were perfused with either horse serum or physiologic saline. After application of AllBond2, ART Bond, Syntac or an experimental dentine bonding agent called P-Bond, a composite cylinder was added and cured at the same time. After 1500 thermal cycles with constant imitation of intrapulpal pressure, the shear bond strengths were measured. Resulting shear bond strength values were analysed with Students t-test or Mann-Whitney Test. The values for AllBond2 were not significantly different. The values for ART Bond (P < 0.05) and for Syntac (P < 0.05) were significantly higher if the dentine was perfused with horse serum. For P-Bond (P < 0.001) the values were significantly higher if the dentine was perfused with physiologic saline. According to these results it does not seem to be appropriate to take a clear decision as to which of the two perfusing media investigated might be more suitable to imitate in vivo conditions.

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