neptune, a Kruppel-like transcription factor that participates in primitive erythropoiesis in Xenopus

The specification of the erythroid lineage from hematopoietic stem cells requires the expression and activity of lineage-specific transcription factors. One transcription factor family that has several members involved in hematopoiesis is the Kruppel-like factor (KLF) family [1]. For example, erythroid KLF (EKLF) regulates beta -globin expression during erythroid differentiation [2-6]. KLFs share a highly conserved zinc finger-based DNA binding domain (DBD) that mediates binding to CACCC-box and GC-rich sites, both of which are frequently found in the promoters of hematopoietic genes. Here, we identified a novel Xenopus KLF gene, neptune, which is highly expressed in the ventral blood island (VBI), cranial ganglia, and hatching and cement glands. neptune expression is induced in response to components of the BMP-4 signaling pathway in injected animal cap explants. Similar to its family member, EKLF, Neptune can bind CACCC-box and GC-rich DNA elements. We show that Neptune cooperates with the hematopoietic transcription factor XGATA-1 to enhance globin induction in animal cap explants. A fusion protein comprised of Neptune's DBD and the Drosophila engrailed repressor domain suppresses the induction of globin in ventral marginal zones and in animal caps. These studies demonstrate that Neptune is a positive regulator of primitive erythropoiesis in Xenopus.

Submandibular gland aplasia and progressive dental caries: A case report

When severe caries occurs in mandibular permanent incisor teeth, the clinician should consider the possibility of associated submandibular gland aplasia or salivary hypofunction. Early diagnosis of submandibular gland disease is essential, as operative problems involving restoration of mandibular incisor teeth are considerable. Furthermore, progressive severe dental caries can present a dilemma for the clinician in affected individuals, despite intensive preventive and restorative therapy. A case report describing severe progressive dental caries and enamel demineralization of the permanent mandibular incisor teeth in a young girl is presented. Further investigation revealed absence of functional bilateral submandibular salivary glands contributing to the rapid breakdown of the teeth despite intensive preventive measures.

Preliminary characterisation and extraction of anterior adhesive secretion in monogenean (platyhelminth) parasites

Secreted anterior adhesives, used for temporary attachment to epithelial surfaces of fishes (skin and gills) by some monogenean (platyhelminth) parasites have been partially characterised. Adhesive is composed of protein. Amino acid composition has been determined for seven monopisthocotylean monogeneans. Six of these belong to the Monocotylidae and one species, Entobdella soleae (van Beneden et Hesse, 1864) Johnston, 1929, is a member of the Capsalidae. Histochemistry shows that the adhesive does not contain polysaccharides, including acid mucins, or lipids. The adhesive before secretion and in its secreted form contains no dihydroxyphenylalanine (dopa). Secreted adhesive is highly insoluble, but has a soft consistency and is mechanically removable from glass surfaces. Generally there are high levels of glycine and alanine, low levels of tyrosine and methionine, and histidine is often absent. However, amino acid content varies between species, the biggest differences evident when the monocotylid monogeneans were compared with E. soleae. Monogenean adhesive shows similarity in amino acid profile with adhesives from starfish, limpets and barnacles. However, there are some differences in individual amino acids in the temporary adhesive secretions of, on the one hand, the monogeneans and, on the other hand, the starfish and limpets. These differences may reflect the fact that monogeneans, unlike starfish and barnacles, attach to living tissue (tissue adhesion). A method of extracting unsecreted adhesive was investigated for use in further characterisation studies on monogenean glues.

Analysis of the sequence and expression of a second putative acetylcholinesterase cDNA from organophosphate-susceptible and organophosphate-resistant cattle ticks

The cattle tick, Boophilus microplus, is a major pest of cattle in Australia, Central and South America, and parts of Africa and Asia. Control of ticks with organophosphates (OPs) and carbamates, which target acetylcholinesterases (AChE), led to evolution of resistance to these pesticides. Alleles at the locus studied here, AChE2, from OP-susceptible female ticks from Australia and Mexico differed at 46 of 1689 nucleotide positions (20 putative amino acid differences) whereas alleles from three strains of OP-resistant ticks from Australia differed with the allele from the Australian susceptible ticks at six to 13 nucleotide positions (three to six putative amino acid differences). However, the role, if any, of these polymorphisms in the OP-resistance phenotype is unknown. Certainly none of the polymorphisms correspond to sites in ACK that are involved in catalysis or binding of acetylcholine in other organisms. Both of the AChE loci of B. microplus, AChE1 and AChE2, are apparently expressed in synganglia; AChE1 is also expressed in salivary glands and ovaries, in OP-susceptible and OP-resistant ticks. This seems to contradict studies of enzyme kinetics, which indicated that only one form of AChE was present in the synganglia, the site of the action of OPs, in this species of tick. (C) 2002 Elsevier Science Ltd. All rights reserved.

Induction of birth in the bandicoot (Isoodon macrourus) with prostaglandin and oxytocin

As in eutherians, maturation of the fetal pituitary and adrenal glands together with an increase in prostaglandin and mesotocin or oxytocin production initiates birth in marsupials. in this study, prostaglandin (Lutalyse) or oxytocin (Syntocinon) were administered to pregnant bandicoots at 05:00 h on the calculated day of birth and the resultant effects were filmed for analysis. The administration of prostaglandin caused the bandicoot to adopt the birth position several minutes after injection (n = 2). However, the bandicoot did not give birth for several hours. Birth occurred at a similar time of day to that observed for untreated bandicoots (n = 7), between 08:00 h and 12:00 h. After an injection of oxytocin, the bandicoot assumed the birth position and birth occurred within several minutes. The young were alive while still connected to their allantoic stalks. However, they were unable to attach to the teats and did not survive (n = 4). The induced young were the colour of venous blood and died soon after the umbilicus was separated, indicating that the cardiopulmonary system of these neonates was underdeveloped and inadequate to maintain life. The results from this study demonstrate that prostaglandin is required to prepare the bandicoot for birth, and mesotocin is required for contraction of the uterus and for birth to occur.

A case of myoepithelial carcinoma displaying biallelic inactivation of the tumour suppressor gene APC in a patient with familial adenomatous polyposis

Familial adenomatous polyposis (FAP) is an autosomal dominant disorder caused by mutation of the APC gene. It is characterised by the appearance of hundreds to thousands of colorectal adenomas in adolescence and the subsequent development of colorectal cancer. Various extracolonic malignancies are associated with FAP, including desmoids and neoplasms of the stomach, duodenum, pancreas, liver, and brain. We present a family affected by FAP with an exon 14 APC mutation displaying two rare extracolonic lesions, a hepatoblastoma and a myoepithelial carcinoma. The hepatoblastoma was found in a male patient aged 2 years. The second lesion, a myoepithelial carcinoma of the right cheek, was found in a female patient aged 14 years. Inactivation of the normal APC allele was demonstrated in this lesion by loss of heterozygosity analysis, thus implicating APC in the initiation or progression of this neoplasm. This is the first reported case of this lesion in a family affected by FAP.

Enhancement or modulation of the vector competence of ochlerotatus vigilax (Diptera : Culicidae) for Ross River virus by temperature

Two different doses of Ross River virus (1111) were fed to Ochlerotatus vigilax (Skuse), the primary coastal vector in Australia; and blood engorged females were held at different temperatures up to 35 d. After ingesting 10(4.3) CCID50/Mosquito, mosquitoes reared at 18 and 25degreesC (and held at the same temperature) had higher body remnant and head and salivary gland titers than those held at 32degreesC, although infection rates were comparable. At 18, 25, and 32degreesC, respectively, virus was first detected in the salivary glands on days 3, 2, and 3. Based on a previously demonstrated 98.7% concordance between salivary gland infection and transmission, the extrinsic incubation periods were estimated as 5, 4, and 3 d, respectively, for these three temperatures. When Oc. vigilax reared at 18, 25, or 32degreesC were fed a lower dosage of 10(3.3) CCID50 RR/mosquito, and assayed after 7 d extrinsic incubation at these (or combinations of these) temperatures, infection rates and titers were similar. However, by 14 d, infection rates and titers of those reared and held at 18 and 32degreesC were significantly higher and lower, respectively. However, this process was reversible when the moderate 25degreesC was involved, and intermediate infection rates and titers resulted. These data indicate that for the strains of RR and Oc. vigilax used, rearing temperature is unimportant to vector competence in the field, and that ambient temperature variations will modulate or enhance detectable infection rates only after 7 d: extrinsic incubation. Because of the short duration of extrinsic incubation, however, this will do little to influence RR epidemiology, because by this time some Oc. vigilax could be seeking their third blood meal, the latter two being infectious.

NPS-2143 - Treatment of osteoporosis - Calcilytic

Efforts to discover new treatments for osteoporosis led to the identification of the potent and selective, small-molecule calcium receptor antagonist NPS-2143. NPS-2143 is the prototype calcilytic drug, designed to act on calcium receptors on the surface of parathyroid glands, stimulating the release of the body's own stores of native parathyroid hormone (PTH). In osteopenic ovariectomized rats, daily oral administration of NPS-2143 resulted in moderate but sustained increases in plasma PTH levels and marked increases in bone formation and resorption, with no net bone gain or loss. The combination of NPS-2143 and estrogen increases bone formation and density to a greater extent than either agent alone. These results suggest that NPS-2143 may be useful in the treatment of established osteoporosis.

Role of PGF(2 alpha) and oxytocin in parturition in the brushtail possum (Trichosurus vulpecula)

Maturation of the fetal pituitary and adrenal glands allows the secretion of cortisol, which in turn leads to an increase in prostaglandin and mesotocin production. The production of prostaglandin and mesotocin results in an increase in uterine contractions and initiates birth in marsupials. The major metabolite of PGF(2alpha), 13,14-dihydro-15-keto-prostaglandin F-2alpha (PGFM), has been found in the plasma of the possum at the time of birth and administration of PGF(2alpha) to female possums induced the adoption of the birth position. Evidence that mesotocin is an integral hormone of birth in the tammar wallaby indicates that both PGF(2alpha) and mesotocin or oxytocin are required for marsupial birth. The presence of PGF(2alpha) receptors in the uterus and corpus luteum of the possum, and the in vitro uterine responsiveness to PGF(2alpha) or oxytocin, were examined. PGF(2alpha) receptors were not observed in possum uteri and the inability of PGF(2alpha) to cause contractions indicates that PGF(2alpha) is not involved directly in contraction of the uterus at parturition. The presence of oxytocin and mesotocin receptors in the uterus of possoms and the ability of oxytocin to induce uterine contraction in vitro supports the view that mesotocin is required for expulsion of the young from the uterus. Low numbers of PGF(2alpha) receptors were found in the possum corpus luteum at birth, indicating an involvement of PGF(2alpha) in regression of the corpus luteum.

Skin toxins and external parasitism of coral-dwelling gobies

Toxic (Gobiodon spp.) and non-toxic (Paragobiodon xanthosomus) gobies became infected with external parasites (gnathiid isopods) at equal rates in a laboratory experiment. Parasites were evenly distributed over the body of P. xanthosomus but were mostly confined to the fins of Gobiodon spp., where toxin glands are less abundant. Skin toxins were not associated with the rate of infection but their distribution did appear to influence the site of parasite attachment. (C) 2003 The Fisheries Society of the British Isles.

Structure of the gut contents of Trichogramma australicum Girault (Hymenoptera : Trichogrammatidae) larvae fixed in situ in eggs of its host Helicoverpa armigera (Hubner) (Lepidoptera : Noctuidae)

Trichogramma australicum larvae develop most rapidly in younger eggs of its host, the pest lepidopteran Helicoverpa armigera . To establish how the developmental stage of the host affects the diet of T. australicum , larvae were fixed in situ in eggs of H. armigera of different ages and the structure of the egg contents and parasitoid gut contents examined histologically. Larvae feeding on newly laid host eggs contain primarily yolk particles in their gut, while larvae feeding on older hosts contain necrotic cells and yolk particles. The gut of T. australicum larvae does not contain organised tissue remnants, indicating that larvae feed primarily by sucking food into their pharynx and feed best on a mixture of particulate semisolids in a liquid matrix. Secretory structures of T. australicum larvae that could be involved in modifying the host environment were examined. The hindgut is modified to form an anal vesicle with a number of attributes suggesting that it may be a specialised secretory structure. The paired salivary glands open to the exterior via a common duct.

The ultrastructure and function of the silk-producing basitarsus in the Hilarini (Diptera : Ernpididae)

The tribe Hilarini (Diptera: Empididae), commonly known as dance flies, can be recognised by their swollen silk-producing prothoracic basitarsus, a male secondary sexual characteristic. The ultrastructure and function of the silk-producing basitarsus from one undescribed morphospecies of Hilarini, 'Hilarempis 20', is presented. Male H. 20 collect small parcels of diatomaceous algae from the surface of freshwater creeks that they bind with silk produced by the gland in the basitarsus. The gift is then presented to females in a nearby swarm, composed predominately of females. The basitarsus houses approximately 12 pairs of class III dermal glandular units that congregate on the ventral side of the cavity. Each gland cell has a large extracellular lumen where secretion accumulates. The lumen drains to the outside via a conducting canal encompassed by a canal cell and a duct extending through the shaft of a specialised secretory spine. The secretory spines lie in pairs in a ventral groove that runs the length of the basitarsus. A comparison of the basitarsal secretory spines with sensilla on the basitarsi of non gland-bearing legs of males, and with non gland-bearing prothoracic. basitarsi of females, suggests that the glandular units are derived from contact chemosensory sensilla. (C) 2003 Elsevier Ltd. All rights reserved.