An improved Morris Water Maze tracking algorithm for psychophysical studies.

An algorithm to track a rat swimming in a Morris Water Maze has been developed. The system is automatically configured to any pool and relative suitable light conditions. It tracks the rat's position and head pose 10 times per second. The output data is displayed in a bitmap and also in a text file. The system was tested with an X - Y plotter using a simulated rat swimming in the maze. Known signals were provided to a model rat and compared to the position and pose information provided by the tracking algorithm. The algorithm was able to track rat velocities up to 2.32 m/s, localize rat position to 4 mm within the maze, and provide head pose information. Early prototypes of the algorithm were also used to track actual rats in a water maze.

Solubilisation and colonisation of wood ash by ectomycorrhizal fungi isolated from a wood ash fertilised spruce forest.

In Sweden application of granulated wood ash has been suggested as a method to supplement nutrient loss resulting from harvesting of forest residues for bioenergy production. Mycelia of two ectomycorrhizal fungi Piloderma sp. 1 and Ha-96-3, were commonly found to colonise ash granules in a wood ash fertilised spruce forest. Thirty-eight fungal isolates were selected from 10 taxa to investigate the possible role of different ectomycorrhizal fungi in nutrient mobilisation from ash. The taxa were Cenococcum geophilum Fr., Piloderma croceum Erikss. and Hjortst., Piloderma sp. 1, Thelephora terrestris (Ehrenb.) Fr., Tylospora fibrillosa Donk, and five unidentified species, all originating from a wood ash fertilised spruce forest. The isolates were tested for their ability to solubilise tricalcium phosphate (TCP) or hardened wood ash (HWA) in vitro. Ha-96-3, P. croceum and Piloderma sp. 1 were the only taxa which solubilised TCP. Abundant calcium oxalate crystals were formed in TCP and HWA plates with Piloderma sp. 1. Ha-96-3 and two isolates of P. croceum produced intermediate amounts of crystals. Ha-96-1 and T. fibrillosa produced low amounts of crystal but no crystal formation was observed by any of the other isolates. Piloderma sp. 1 from HWA plates had significantly higher concentrations of P, compared to P. croceum or Ha-96-3. Piloderma sp. 1 and P. croceum were further tested for their ability to colonise wood ash in microcosms containing intact mycorrhizal associations. After 7 months Piloderma sp. 1 colonised ash amended patches with a dense, mat like mycelium, whereas P. croceum mycelia avoided the ash patches. Possible differences between these fungi in patterns of carbon allocation were investigated by labelling seedlings with 14CO(2). Piloderma sp. 1 mycelia allocated significantly more 14C to ash patches than P. croceum. P. croceum allocated relatively more 14C to control patches than to the ash patches. The possible role of ectomycorrhizal fungi in mobilisation of nutrients from wood ash is discussed.

Identification of the ectomycorrhizal basidiomycete Tylospora fibrillosa Donk by RFLP analysis of the PCR-amplified ITS and IGS regions of ribosomal DNA.

Sitka spruce mycorrhizas, macroscopically identified as being formed by Tylospora fibritiosa Donk, were sampled from a young and on old plantation and the mycobionts were isolated into pure culture. DNA was extracted and fragments of the ribosomal DNA (rDNA) were amplified using the polymerase chain reaction (PCR). The primers were directed to conserved regions of fungal rDXA and hybridize to a wide range of fungi. One amplified region includes the internal spacer (ITS) region which has a low degree of conservation. The JTS amplification products, which were approximately 600 base pairs (bp), were digested with a variety of restriction endonucleases in order to detect restriction fragment length polymorphisms (RFLPs). The RFLPs clearly separated T. fibrillosa from other ectomycorrhizal species but there were only minor differences between the T. fibrillosa isolates. PCR amplification of the ITS region, digestion with the endonudeasc HinfI and examination of the RFLPs produced proved to be a rapid method by which to distinguish T. fibriHosa from a large number of other basidiomyictes. The method was also applied to DNA extracted, from single mycotrhizal root tips. The imergenic spacer region (1GS) of the rDNA is more variable than the ITS region in several fungal species. The 5'end of the 25S and the intergenic region between the 25S and the 5S genes were amplified and analyzed as above. Polymorphisms between T. fibritiosa isolates within this region were limited and RFLPs were not useful m discriminating between isolates, suggesting a low genetic variability in this species.