A role for endocytic recycling in hyphal growth.

Actin plays multiple complex roles in cell growth and cell shape. Recently it was demonstrated that actin patches, which represent sites of endocytosis, are present in a sub-apical collar at growing tips of hyphae and germ tubes of filamentous fungi. It is now clear that this zone of endocytosis is necessary for filamentous growth to proceed. In this review evidence for the role of these endocytic sites in hyphal growth is examined. One possibility if that the role of the sub-apical collar is associated with endocytic recycling of polarized material at the hyphal tip. The 'Apical Recycling Model' accounts for this role and predicts the need for a balance between endocytosis and exocytosis at the hyphal tip to control growth and cell shape. Other cell differentiation events, including appressorium formation and Aspergillus conidiophore development may also be explained by this model.

acon-3, the Neurospora crassa ortholog of the developmental modifier, medA, complements the conidiation defect of the Aspergillus nidulans mutant.

Aspergillus nidulans and Neurospora crassa are ascomycetes that produce asexual spores through morphologically distinct processes. MedA, a protein with unknown function, is required for normal asexual and sexual development in A. nidulans. We determined that the N. crassa ortholog of medA is acon-3, a gene required for early conidiophore development and female fertility. To test hypotheses about the evolutionary origins of asexual development in distinct fungal lineages it is important to understand the degree of conservation of developmental regulators. The amino acid sequences of A. nidulans MedA and N. crassa ACON-3 shared 37% identity and 51% similarity. acon-3 is induced at late time points of conidiation. In contrast, medA is constitutively expressed and MedA protein localizes to nuclei in all tissue types. Nonetheless, expression of acon-3 using its native promoter complemented the conidiation defects of the A. nidulans ΔmedA and medA15 mutants. We conclude that the biochemical activity of the medA orthologs is conserved for conidiation.

Oral rehabilitation for a patient with oligodontia and maxillary hypoplasia.

An 18 year old female with oligodontia and maxillary hypoplasia was treated using an interdisciplinary team approach involving orthodontists, maxillofacial surgeons and prosthodontists. Full mouth one-piece fixed partial dentures were the final restoration. The fixed partial dentures fabricated for the maxilla and mandible using the concept of a shortened dental arch resulted in improved esthetics and the masticatory function. This paper describes the treatment procedures for an oligodontia patient with alveolar bone hypoplasia.