Overexpression of sonic hedgehog suppresses embryonic hair follicle morphogenesis

The Sonic Hedgehog (Shh) signalling pathway plays a central role in the development of the skin and hair follicle and is a major determinant of skin tumorigenesis, most notably of basal cell carcinoma (BCC). Various mouse models involving either ablation or overexpression of key members of the Shh signalling pathway display a range of skin tumours. To further examine the role of Shh in skin development. we have overexpressed Shh in a subset of interfollicular basal cells from 12.5 dpc under the control of the human keratin 1 (HK1) promoter. The HK1-Shh transgenic mice display a range of skin anomalies, including highly pigmented inguinal lesions and regions of alopecia. The most striking hair follicle phenotype is a suppression in embryonic follicle development between 14.0 and 19.0 dpc, resulting in a complete absence of guard, awl, and auchene hair fibres. These data indicate that alternative signals are responsible for the development of different hair follicles and point to a major role of Shh signalling in the morphogenesis of guard, awl, and auchene hair fibres. Through a comparison with other mouse models, the characteristics of the HK1-Shh transgenic mice suggest that the precise timing and site of Shh expression are key in dictating the resultant skin and tumour phenotype. 2003 Elsevier Inc. All rights reserved.

Transdermal delivery of a tetrapeptide: Evaluation of passive diffusion

Skin penetration of the tetrapeptide Ac-Ala-Ala-Pro-Val-NH2 was assessed. This peptide sequence fits the P-P-1 subsites of elastase and inhibits human neutrophil elastase competitively. Consequently this peptide may be therapeutically useful in a variety of inflammatory disorders, including psoriasis. in which elevated levels of human neutrophil elastase have been reported. Peptide penetration was assessed across whole human skin, whole skin with the stratum corneum removed by tape stripping and epidermis, which had been removed from the dermis by heat separation. The influence of 75% aqueous ethanol as a potential penetration enhancer of the tetrapeptide across epidermis was also assessed. The tetrapeptide did not penetrate whole human skin or epidermis, even under the influence of 75% aqueous ethanol. However, when the stratum corneum was removed tetrapeptide flux of 73.39 mug cm(-2) h(-1) was achieved. The study demonstrates that the stratum corneum is the main barrier to tetrapeptide skin penetration and must be overcome if therapeutically relevant amounts of tetrapeptide are to be delivered to the skin.

Prosorhynchoides lamprelli n. sp (Digenea : Bucephalidae) from the brassy trevally, Caranx papuensis (Teleostei : Carangidae), from off Lizard Island on the Great Barrier Reef, Australia

Prosorhynchoides lamprelli n. sp. ( Digenea: Bucephalidae) is described from the intestine of the brassy trevally, Caranx papuensis (Carangidae) from off Lizard Island, Great Barrier Reef, Australia. The new species is differentiated from other species of Prosorhynchoides Dollfus, 1929 by the shape and distribution of its vitelline follicles, the shape and extent of its uterus and the configuration of its digestive system. This is the first bucephalid to be described from Caranx papuensis; we have not encountered this species from other carangids or from over 1,500 individuals of other teleosts species we have found to be infected with bucephalids from the Great Barrier Reef.

Chaulioleptos haywardi n. gen., n. sp (Digenea : Sanguinicolidae) from Filimanus heptadactyla (Perciformes : Polynemidae) of Moreton Bay, Australia

Here we describe the first Species of sanguinicolid blood fluke (Trematoda: Digenea) from a polynemid fish. Chaulioleptos haywardi n. gen., n. sp. is described from Filimanus heptadacryla Cuvier, 1829 (Perciformes: Polynemidae), the sevenfinger threadfin from Sandgate, Moreton Bay (southeast Queensland, Australia). Chaidioleptos haywardi differs from existing sanguinicolid genera in the combined possession of the following 7 characters: 2 testes, an entirely postovarian uterus, a uterine chamber, separate genital pores, an H-shaped intestine with abbreviated anterior caeca, tegumental spines in incomplete ventromarginal transverse rows that are continuous along the length of the body, and vitelline follicles that are tightly compacted and subsequently appear to form a solid branching mass occupying the area anterior to intestinal bifurcation and extending posteriorly to the level of the posterior margin of the anterior testis. Chaulioleptos haywardi is most closely related to Paracardicola Martin, 1960 and Adelomyllos Nolan and Cribb, 2004.

Sanguinicola maritimus n. sp (Digenea : Sanguinicolidae) from Labridae (Teleostei : Perciformes) of southern Australian waters

A new species of Sanguinicola Plehn, 1905 is described from the marine teleosts Notolabrus parilus (Richardson) and N. tetricus (Richardson) (Perciformes: Labridae) from Western Australian and Tasmanian waters. This host distribution is strikingly anomalous; however, the present material fulfils the morphological criteria of Sanguinicola. S. maritimus n. sp. differs from previously described species in having the combination of a body 1,432-1,701 mu m long, the oesophagus 18.3-21.7% of the body length, the testis occupying 42.8-52.3% of the body length, an oviducal seminal receptacle and Mehlis' gland present, ovoid eggs, and vitelline follicles that extend anteriorly past the nerve commissure, laterally past the lateral nerve chords and posteriorly to the anterior margin of the cirrus-sac. S. maritimus also lacks a protrusible anterior proboscis. It also differs in the combination of host and geographical location, being the first Sanguinicola species from a marine teleost and the first from Australian waters.

First report of a bucephalid digenean from an apogonid teleost: Prosorhynchoides apogonis n. sp from Cheilodipterus macrodon on the southern Great Barrier Reef, Australia

Prosorhynchoides apogonis n. sp. (Digenea: Bucephalidae) is described from the intestine of the apogonid Cheilodipterus macrodon on the southern Great Barrier Reef, Australia. The new species is differentiated from other species of Prosorhynchoides Dollfus, 1929 by the configuration of its digestive system, shape and distribution of its vitelline follicles, and the shape and extent of its uterus. This is the first bucephalid to be described from the teleost family Apogonidae, and our records suggest that this species is strongly host-specific, at least to the genus Cheilodipterus. The host family is consistent with the pattern of Prosorhynchoides being reported from a very wide range of piscivorous fish families. As a result of comparisons made in the description of this species, 18 species formerly included in Bucephaloides Hopkins, 1954, Bucephalopsis Diesing, 1855 and Neobucephalopsis Dayal, 1948 are transferred to Prosorhynchoides, 16 as new combinations and two as replacement names to prevent secondary homonymy.

Optimization of a transplant model to assess skin reconstitution from stem cell-enriched primary human keratinocyte populations

Given that an important functional attribute of stem cells in vivo is their ability to sustain tissue regeneration, we set out to establish a simple and easy technique to assess this property from candidate populations of human keratinocyte stem cells in an in vivo setting. Keratinocytes were inoculated into devitalized rat tracheas and transplanted subcutaneously into SCID mice, and the epithelial lining regenerated characterized to establish the validity of this heterotypic model. Furthermore, the rate and quality of epidermal tissue reconstitution obtained from freshly isolated unfractionated vs. keratinocyte stem cell-enriched populations was tested as a function of (a) cell numbers inoculated; and (b) the inclusion of irradiated support keratinocytes and dermal cells. Rapid and sustained epidermal tissue regeneration from small numbers of freshly isolated human keratinocyte stem cells validates the utilization of this simple and reliable model system to assay for enrichment of epidermal tissue-reconstituting cells.

CXCR4/SDF1 interaction inhibits the primordial to primary follicle transition in the neonatal mouse ovary

The molecular mechanisms behind the entry of the primordial follicle into the growing follicle pool remain poorly understood. To investigate this process further, a microarray-based comparison was undertaken between 2-day postpartum mouse ovaries consisting of primordial follicles/naked oocytes only and those with both primordial follicles and newly activated follicles (7-day postpartum). Gene candidates identified included the chemoattractive cytokine stromal derived factor-1 (SDF1) and its receptor CXCR4. SDF1 and CXCR4 have been implicated in a variety of physiological processes including the migration of embryonic germ cells to the gonads. SDF1-alpha expression increased with the developmental stage of the follicle. Embryonic expression was found to be dichotomous post-genii cell migration, with low expression in the female. Immunohistochemical studies nonetheless indicate that the autocrine pattern of expression ligand and receptor begins during embryonic life. Addition of recombinant SDF1-alpha to neonatal mouse ovaries in vitro resulted in significantly higher follicle densities than for control ovaries. TUNEL analysis indicated no detectable difference in populations of apoptotic cells of treated or control ovaries. Treated ovaries also contained a significantly lower percentage of activated follicles as determined by measurement of oocyte diameter and morphological analysis. Treatment of cultured ovaries with an inhibitor of SDF1-alpha, AMD3100, ablated the effect of SDF1-alpha. By retaining follicles in an unactivated state, SDF1/CXCR4 signaling may play an important role in maintaining the size and longevity of the primordial follicle pool. (c) 2006 Elsevier Inc. All rights reserved.

Evolutionary conservation and murine embryonic expression of the gene encoding the SERTA domain-containing protein CDCA4 (HEPP)

Cdca4 (Hepp) was originally identified as a gene expressed specifically in hematopoietic progenitor cells as opposed to hematopoietic stem cells. More recently, it has been shown to stimulate p53 activity and also lead to p53-independent growth inhibition when overexpressed. We independently isolated the murine Cdca4 gene in a genomic expression-based screen for genes involved in mammalian craniofacial development, and show that Cdca4 is expressed in a spatio-temporally restricted pattern during mouse embryogenesis. In addition to expression in the facial primordia including the pharyngeal arches, Cdca4 is expressed in the developing limb buds, brain, spinal cord, dorsal root ganglia, teeth, eye and hair follicles. Along with a small number of proteins from a range of species, the predicted CDCA4 protein contains a novel SERTA motif in addition to cyclin A-binding and PHD bromodomain-binding regions of homology. While the function of the SERTA domain is unknown, proteins containing this domain have previously been linked to cell cycle progression and chromatin remodelling. Using in silico database mining we have extended the number of evolutionarily conserved orthologues of known SERTA domain proteins and identified an uncharacterised member of the SERTA domain family, SERTAD4, with orthologues to date in human, mouse, rat, dog, cow, Tetraodon and chicken. Immunolocalisation of transiently and stably transfected epitope-tagged CDCA4 protein in mammalian cells suggests that it resides predominantly in the nucleus throughout all stages of the cell cycle. (c) 2006 Elsevier B.V. All rights reserved.

Remodeling of extracellular matrix at ovulation of the bovine ovarian follicle

Using immunohistochemistry and RNA analyses we examined the fate of components of a newly identified matrix that develops between granulosa cells (focimatrix, abbreviated from focal intraepithelial matrix) and of the follicular basal lamina in ovulating bovine ovarian follicles. Pre- and postovulatory follicles were generated by treatment with estradiol (Day 1), progesterone (Days 1-10), and prostaglandin analogue (Day 9) with either no further treatment (Group 1, n = 6) and or with 25 mg porcine LH (Day 11, Group 2, n = 8 or Day 10, Group 3, n = 8) and ovariectomy on Day 12 (12-14 hr post LH in Group 2, 38-40.5 hr in Group 3). In the time frame examined no loss of follicular basal lamina laminin chains beta 2 and gamma 1 or nidogen 1 was observed. In the follicular basal lamina collagen type IV alpha 1 and perlecan were present prior to ovulation; after ovulation collagen type IV alpha 1 was discontinuously distributed and perlecan was absent. Versican in the theca interna adjacent to the follicular basal lamina in preovulatory follicles was not observed post ovulation, however, the granulosa cells then showed strong cytoplasmic staining for versican. Expression of versican isoforms V0, V1, and V3 was detected at all stages. Focimatrix was observed in preovulatory follicles. It contained collagen type IV alpha 1, laminins beta 2 and gamma 1, nidogen 1 and perlecan and underwent changes in composition similar to that of the follicular basal lamina. In conclusion focimatrix and the follicular basal lamina are degraded at ovulation. Individual components are lost at different times.

Stephanostomum talakitok n. sp (Digenea : Acanthocolpidae) from the golden trevalley, Gnathanodon speciosus (Perciformes : Carangidae), from Ningaloo Reef, Western Australia

A new species, Stephanostomum talakitok n. sp., is described from the golden trevally Gnathanodon speciosus, Ningaloo Reef, Western Australia. It has 36 (34-40) circum-oral spines and the vitellarium reaches to no less than 10-17% of the hindbody length from the ventral sucker. It differs from other species of Stephanostomum with these characteristics by combinations of the gradual diminution of the circum-oral spine size to a small mid-ventral spine, the contiguous gonads with no intervening vitelline follicles, the sucker-ratio and various other ratios, including the distance between the ventral sucker and the ovary and the distance the cirrus-sac reaches into the hindbody, both as a proportion of body length.

Birth weight and age at menopause in Australian female twin pairs: exploration of the fetal origin hypothesis

In a twin sample where duration of gestation can be controlled, a specific example of the fetal origins hypothesis concerning association between low birth weight and early age at menopause is explored. The hypothesis is based on the physiologically plausible path from intrauterine growth retardation and reduced numbers of primary follicles to an earlier menopause. The sample comprised 323 Australian female twin pairs where both co-twins had reached menopause naturally and reported on their weight at birth. Regression analysis showed no linear association between the two variables (P = 0.371, r(2) = 0.0009). Intra-pair differences in age at menopause were investigated in the context of relative birth weight of co-twins. In 265 pairs an intra-pair birth a eight difference was reported. In monozygotic (MZ) pairs (n = 168) this allowed for control of genetic effects as well as gestation duration. No significant differences dependent on birth weight relative to co-twin were found for age at natural menopause in either MZ or dizygotic (DZ) twin pairs, even in pairs whose birth weights differed markedly. There was some indication that twins with premature ovarian failure were heavier at birth than twins with normal or later menopausal age. We conclude that the hypothesis that lower birth weight is associated with earlier menopause is not supported by our data.