The mouse pelage hair consists of three types of hair coined primary (guard), secondary (awls and auchenes) and tertiary (zigzag) hair. They display distinct morphologies and are induced consecutively during hair morphogenesis. Previously two identified regulatory mouse mutants, Yellow submarine (Ysb) and Light coat and circling (Lcc) which the chromosomal rearrangements have disrupted the cis-acting regulatory elements of Sox2; resulting in the loss of Sox2 expression in the inner ear. The mutants displayed lighter hair coat color due to a reduction in the proportion of secondary hair and increased proportion of tertiary hair. Sox18 null mutants display darker coat colour and reduced proportion of zigzag hair. To dissect the underlying mechanisms of the phenotypes in hair type specification in 〖Sox2〗^Ysb and 〖Sox2 〗^Lcc mutants and the role of Sox2 and Sox18 in regulating the process; the expression of Sox2 in the hair follicle and the change in the density of hair types in mutants were analyzed. I have identified the expression pattern of Sox2 in the dermal papilla (DP) of the hair follicle and verified its down-regulation in 〖Sox2〗^Ysband 〖Sox2 〗^Lcc mutants. The DP at the base of hair follicle is the signaling center for the regulation of hair development. Sox2 is specifically expressed in the DP of primary and secondary but not in tertiary hair while Sox18 is expressed in the DP of all hair types. Analysis of Sox2 mutants showed that the number of secondary hair was normal at induction but was reduced and accompanied by an increase in tertiary hair in adult mice. The number of tertiary hair was reduced in Sox18 null mutants. To gain insight into the molecular basis of hair type specification and potential targets of Sox2 in the regulation, gene expression profile in DP cells of 〖Sox2 〗^(EGFP/+)and 〖Sox2 〗^(EGFP/Ysb) mice was examined; the data suggests that genes in the Wnt and BMP signalling pathway were down-regulated in Sox2 mutants; while Runx3 and Corin may act downstream of Sox2 in regulating hair type specification and pigmentation. Hair follicles enter cycles of growth and regression throughout life during the hair cycle. Sox2 was only expressed in the growth phase while Sox18 was persistently expressed throughout the hair cycle. I further asked if Sox2 and Sox18 regulate post-natal hair development by analysing the expression pattern of Sox2 and Sox18 in wildtype mice and mutants throughout the hair cycle and the progression of hair growth in the mutants. The growth phase of the first hair cycle was extended in Sox2 mutants while the hair cycle in Sox18 null mutants was normal. Cell proliferation was compromised during hair regeneration leading to a delay in hair regeneration in Sox2 mutants. Sox2 and Sox18 showed overlapping expression in the DP and both regulate hair type specification. To test if Sox2 and Sox18 synergistically regulate hair development, the 〖Sox2〗^(Ysb/Ysb);〖Sox18〗^(-/-) mutants have been generated. Hair morphogenesis and differentiation were impaired; while the number of tertiary hair was increased with reduced number of secondary hair, which phenocopied that of Sox2 mutants. In conclusion, the results suggest that Sox2 and Sox18 functions synergistically on the regulation of hair growth and differentiation. / published_or_final_version / Biochemistry / Doctoral / Doctor of Philosophy

No description available.

A study was carried out on phosphatase activity, phosphate uptake and its relationship to hair formation in the Rivulariaceae. The Rivulariaceae was chosen as it is a widespread taxon, where hair formation is a common occurrence, and previous studies indicated that they originate from environments where a large proportion of the phosphorus (P) is present as organic P. It seems possible that hair-forming Rivulariaceae are especially well adapted to utilize organic P. Initially 51 axenic cyanobacterial strains, from 10 genera, were screened for yields using organic P sources and for cell-bound and extracellular phosphomonoesterase (PMEase) and phosphodiesterase (PDEase) activities. All strains exhibited detectable inducible PMEase activities, and highest cell-bound PMEase activities were in hair-forming Rivulariaceae. Synechococcus had significantly low cell-bound phosphatase activities and five strains were unable to hydrolyze phytic acid. PDEase activities were lower compared to PMEase activities in all strains. Strains isolated from deepwater rice habitats had significantly higher levels of PDEase activity. In the three Calothrix strains tested, Calothrix 202, 550 and 603, inducible phosphatase activities were similar whether the P source was inorganic or organic. PMEase synthesis in these strains began when cellular P (% dry wt) values were in the range 0.60 - 1.0%. Differences in the influence of environmental variables on cell-bound and extracellular PMEase activities in hair-forming Calothrix 550 were slight, suggesting that PMEases in the two fractions had a common origin. Of the eleven ions tested Ca had the most pronounced stimulatory effect on PMEase activity. Localization of enzyme activity in Calothrix 550 suggested that the enzyme was bound to a surface. Partial purification of an extracellular PMEase fraction detected four bands of PMEase activity on a non-denaturing polyacrylamide gel. Three of the four bands were associated with carbohydrate and the bands were not extractable by mechanical means. Localization of PMEase activity in hair-forming strains by azo dye (naphthol AS-MX) and 5-bromo-4-chloro-3-indolyl phosphate (BCIP) showed that PMEase activity was associated with hair cells. Phosphate uptake experiments with Calothrix 253 and 550 suggested that uptake at high external phosphate concentrations was located in hair cells. NaCl, above 67.5 mM, inhibited hair formation and subsequently phosphatase activity in Calothrix 253 and 690. Addition of mannitol or sorbitol had no effect on hair formation, suggesting inhibition of hair formation was not an osmotic effect. Removal of P-deficient cultures from saline to freshwater media led to a marked synchronization of hair formation (in 90% of trichomes) and increase in cell-bound PMEase activity. Localization of cell-bound PMEase activity by light microscopy, using naphthol AS-MX, detected activity in the hair cells.

Bibliography : leaves 153-162. / xi, 162 leaves : ill. (chiefly col.) ; 30cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The objective of this project was to isolate follicle-derived cDNA clone(s) encoding putative L-cysteine transport proteins, and to determine their amino acid transport function in virto. / Thesis (Ph.D.)--University of Adelaide, Dept. of Animal Science, 2000

Thesis (M. Phil.)--University of Hong Kong, 2007. / Also available online.

Thesis (Ph. D.)--University of Adelaide, Dept. of Biochemistry, 1985. / Offprints of the author's articles inserted. Includes bibliographical references (leaves [122]-145).

Thesis (M.Sc.) -- University of Adelaide, Dept. of Biochemistry, 1977. / Reprint of Journal of Investigative Dermatology, v.6 no.5, pt.1 asan appendix.

Thesis (Ph.D.) -- University of Adelaide, Dept. of Animal Science, 2000. / Bibliography : leaves 153-162.

Thesis (Ph.D.)--University of Adelaide, Dept. of Biochemistry, 1991. / Includes bibliographical references.

Thesis (Masters in App. Sci.) -- University of Canberra, 2007. / Includes bibliography (p. 147 - 163).