On the ascus types in thePhysciaceae (Lecanorales)

Comparative studies in thePhysciaceae revealed that characters of the apical apparatus of asci differ between the various genera. Two major ascus types are observable in this family. They are found to correspond with certain ascospore types.     

miR-196 is an essential early-stage regulator of tail regeneration, upstream of key spinal cord patterning events

Salamanders have the remarkable ability to regenerate many body parts following catastrophic injuries, including a fully functional spinal cord following a tail amputation. The molecular basis for how this process is so exquisitely well-regulated, assuring a faithful replication of missing structures every time, remains poorly understood. Therefore a study of microRNA expression and function during regeneration in the axolotl, Ambystoma mexicanum, was undertaken. Using microarray-based profiling, it was found that 78 highly conserved microRNAs display significant changes in expression levels during the early stages of tail regeneration, as compared to mature tissue. The role of miR-196, which was highly upregulated in the early tail blastema and spinal cord, was then further analyzed. Inhibition of miR-196 expression in this context resulted in a defect in regeneration, yielding abnormally shortened tails with spinal cord defects in formation of the terminal vesicle. A more detailed characterization of this phenotype revealed downstream components of the miR-196 pathway to include key effectors/regulators of tissue patterning within the spinal cord, including BMP4 and Pax7. As such, our dataset establishes miR-196 as an essential regulator of tail regeneration, acting upstream of key BMP4 and Pax7-based patterning events within the spinal cord.     

Giardia intestinalis: electrophoretic evidence for a species complex

The technique of allozyme electrophoresis was applied to 29 Australasian stocks and 48 clones of Giardia intestinalis from humans as a means of increasing the number of genetic markers currently available for identification and classification. Fifty different enzymes were examined and of these 26 loci were found to be suitable for use as genetic markers. The data indicate the presence of four discrete genetic groups within the sample of G. intestinalis examined. The groups had fixed genetic differences at 23-69% of loci established. The evidence suggests that G. intestinalis is a species complex. The results have important implications for the systematics of human isolates of Giardia, as well as for studies on the epidemiology and demography of giardiasis in Australia and elsewhere.