The West Pacific diversity hotspot as a source or sink for new species? Population genetic insights from the Indo-Pacific parrotfish Scarus rubroviolaceus.

We used a population genetic approach to quantify major population subdivisions and patterns of migration within a broadly distributed Indo-Pacific parrotfish. We genotyped 15 microsatellite loci in Scarus rubroviolaceus collected from 20 localities between Africa and the Americas. A STRUCTURE model indicates the presence of four major populations: Eastern Pacific, Hawaii, Central-West Pacific and a less well-differentiated Indian Ocean. We used the isolation and migration model to estimate splitting times, population sizes and migration patterns between sister population pairs. To eliminate loci under selection, we used BayeScan to select loci for three isolation and migration models: Eastern Pacific and Central-West Pacific, Hawaii and the Central-West Pacific, and Indian Ocean and the Central-West Pacific. To test the assumption of a stepwise mutation model (SMM), we used likelihood to test the SMM against a two-phase model that allowed mutational complexity. A posteriori, minor departures from SMM were estimated to affect ≤2% of the alleles in the data. The data were informative about the contemporary and ancestral population sizes, migration rates and the splitting time in the eastern Pacific/Central-West Pacific comparison. The model revealed a splitting time ∼17,000 BP, a larger contemporary N(e) in the Central-West Pacific than in the eastern Pacific and a strong bias of east to west migration. These characteristics support the Center of Accumulation model of peripatric diversification in low-diversity peripheral sites and perhaps migration from those sites to the western Pacific diversity hotspot.

Experimental realization of a Rydberg optical Feshbach resonance in a quantum many-body system.

Feshbach resonances are a powerful tool to tune the interaction in an ultracold atomic gas. The commonly used magnetic Feshbach resonances are specific for each species and are restricted with respect to their temporal and spatial modulation. Optical Feshbach resonances are an alternative which can overcome this limitation. Here, we show that ultra-long-range Rydberg molecules can be used to implement an optical Feshbach resonance. Tuning the on-site interaction of a degenerate Bose gas in a 3D optical lattice, we demonstrate a similar performance compared to recent realizations of optical Feshbach resonances using intercombination transitions. Our results open up a class of optical Feshbach resonances with a plenitude of available lines for many atomic species and the possibility to further increase the performance by carefully selecting the underlying Rydberg state.

Effect of prostaglandin E(2) on the proliferation, Ca(2+) mobilization and cAMP in HT-29 human colon adenocarcinoma cells.

Several lines of evidence suggest that non-steroidal antiinflammatory drugs (NSAIDs) have anticarcinogenic effects. The causal relationship linking the preventive effect of NSAIDs on colon cancer and the inhibition of prostaglandin synthesis is questioned by the contrasting results obtained by many laboratories. The experiments reported in this paper demonstrate that prostaglandin E(2) (PGE(2)) did not stimulate the proliferation in HT-29 human colon adenocarcinoma cells under several experimental conditions. Moreover, PGE(2) and 17-phenyl trinor prostaglandin E(2) (a specific agonist of EP1 receptors) did not increase intracellular Ca(2+) concentration. Finally, PGE(2) did not affect the intracellular cAMP and did not reduce the isoproterenol dependent increase in cAMP. These results indicate that in HT-29 cells: (1) proliferation is not directly sensitive to PGE(2); and (2) PGE(2) does not stimulate a signal transduction pathway leading to intracellular increase in cAMP or Ca(2+) mobilization. Therefore, other cell lines should be used to assess the direct role played by prostanoids in promoting cell proliferation in colon cancer.

The proliferative response of HT-29 human colon adenocarcinoma cells to bombesin-like peptides.

Bombesin-like peptides (BLP) and their receptors are widely distributed throughout the intestine and are potential mitogens for gastrointestinal cancers. In this study we characterized the proliferation induced by BLP in the human adenocarcinoma cell line HT-29. The number of HT-29 cells, partially serum deprived (1% fetal bovine serum) for 48 h, was increased after 24 h of stimulation with bombesin, GRP, neuromedin B (NMB) and neuromedin C (NMC) ranging from 0.1 nM up to 1 microM. Reverse transcription polymerase chain reaction studies, revealed the presence of mRNA for NMB and for the GRP preferring receptor (GRP-R). mRNA for GRP, NMB preferring receptor (NMB-R) and bombesin receptor subtype 3 (BRS-3) were not detected. [D-Phe(6)]bombesin-(6-13)methyl ester (A1) and BIM-23127 (A2), are considered as inhibitors of binding to GRP-R and NMB-R, respectively. Surprisingly, A1 and A2 stimulated the proliferation of HT-29 cells. Moreover, in the simultaneous presence of 1 microM A1 and 0.1 microM GRP or 0.1 nM or 0.1 microM bombesin, inhibition of the proliferation was observed. Our data demonstrate that the proliferation induced by BLP in HT-29 cells is due to interaction with the GRP-R.

Actions of tachykinins on the ion transport across the frog skin.

The tachykinin-dependent stimulation of ion transport across frog skin was studied. Tachykinin stimulation was due to interaction with an NK1-like receptor as [Sar9-Met(O2)11]-Substance P (a very selective NK1 agonist) strongly stimulated SCC, whereas [beta-Ala8]-Neurokinin A 4-10 (a very selective NK2 agonist) did not. The rank order of tachykinin potency was: PG-KI > Uperolein > Hylambatin > Kassinin > Phyllomedusin > [Sar9-Met(O2)11]-Substance P > Ranatachykinin A > Physalaemin > Ranakinin > Substance P and Eledoisin >> Neurokinin A. Neurokinin B, Scyliorhinin I, Urechistachykinin I and Urechistachykinin II had no effect. We conclude that the minimal structural requirements for stimulating SCC in the frog skin were the presence of: a) the C-terminal sequence Phe-X-Gly-Leu-Met-NH2; b) at least one Pro residue in the N-terminal sequence.

Differences between ranamargarin and other tachykinins in the stimulation of ion transport in frog skin.

In frog skin, tachykinins stimulate ion transport by interaction with NK1-like receptors. The structural requirements of the peptide are the presence of the C-terminal sequence Phe-X-Gly-Leu-Met-NH(2) and at least one Pro residue in the N-terminal sequence. In this paper, we demonstrate that the C-terminal amino acid must be amidated but it can be different from Met, and that the sequence cannot be longer or shorter than 11-12 amino acids. Unexpectedly, Ranamargarin (14 amino acids, no Pro residue) increased the short circuit current value by 48 +/- 0.3%. On the basis of considerable experimental evidence, we suggest that Ranamargarin interacts with a receptor different from those of other tachykinins.

Bradykinin stimulation does not induce intracellular Ca2+ elevation in cells from desmoid tumors.

The intracellular mechanisms controlling cell proliferation in desmoid tumors (DT) are unknown. Bradykinin stimulated an increase in [Ca2+](i), (monitored by the fura-2 fluorescence) in fibroblasts obtained from both the skin of a normal donor and the mesenter of a familial adenomatous polyposis (FAP) patient. Cells from DT of the same patient as well as those from another FAP patient failed to show the elevation of [Ca2+](i) usually caused by bradykinin stimulation.

Lack of effect by prostaglandin F2alpha on the proliferation of the HCT-8 and HT-29 human adenocarcinoma cell lines.

A variety of studies have supported the finding that regular intake of aspirin or non-steroidal anti-inflammatory drugs can affect colorectal cancer carcinogenesis by decreasing the synthesis of prostaglandins (PGs). We report that PG F2alpha, in the presence of indomethacin, did not stimulate the proliferation in HCT-8 and HT-29 human colon adenocarcinoma cells. Moreover, in both cell lines fluprostenol, a specific agonist of FP receptors, did not increase intracellular Ca2+ concentration, monitored with the fluorescent dye fura-2. These results indicate that in HCT-8 and HT-29 cells: i) proliferation is not sensitive to PG F2alpha; ii) functional FP receptors are absent. Therefore, either PG F2alpha is not necessarily involved in the proliferation of colorectal mucosa or cell lines other than HCT-8 and HT-29 should be used to assess the role played by PG F2alpha in promoting cell proliferation in colon cancer.

Action of physalaemin on the ionic transport across the frog skin.

The effects of the non-mammalian tachykinin physalaemin were studied on the short circuit current (SCC) and on both influx (Ji) and outflux (Jo) of 36Cl- and 22Na+ across the isolated skin of Rana esculenta. Physalaemin, added to the internal bathing fluid, increased SCC in a dose-dependent manner with a maximal effect at 1 microM. This increase was due to a stimulation of both Na+ absorption and Cl- secretion. Bumetanide (20 microM in the internal fluid), an inhibitor of the Na+/K+/2Cl- cotransporter, reduced the action of physalaemin on SCC by 46%. Furthermore diphenylamine-2-carboxylic acid (DPC, 0.1 mM in the external fluid), an inhibitor of Cl- channels, decreased the effect of the peptide on SCC by 48%. It is concluded that physalaemin activates the Na+/K+/2Cl- cotransporter at the basolateral membrane, accumulating Cl- in the cells and favouring its exit through Cl- channels at the outermost membrane of the epithelium. An inhibitor of cyclooxygenases, i.e. naproxen, strongly inhibited the physalaemin effect on SCC, whereas 5,8,11-eicosatriynoic acid (ETI), an inhibitor of lipooxygenases was without effect. Therefore, it is proposed that prostaglandins (probably PGE2) are the cellular mediators of this action. An antagonist of NK1 receptors for tachykinins, CP 99,994, inhibited the physalaemin action on SCC, whereas challenge with SR 48,968, an antagonist of NK2 receptors, had no effect on physalaemin action. It is concluded that physalaemin effect on SCC in frog skin is mediated by its interaction with NK1 receptors.

Na+ and Cl- net absorption by the isolated skin of Rana esculenta.

In the last five years, several measurements of 22Na+ influx (Ji) and outflux (Jo) across symmetrical parts of the isolated skin of Rana esculenta, under permanent short circuitation, were performed in our Institute. The mean value of the 22Na+ net fluxes (Ji-Jo) exceeded the mean value of the short circuit current measurements (1.14 +/- 0.04 versus 0.98 +/- 0.02 microE.cm-2.h-1, 253 experiments). Since this discrepancy could be due to a concomitant Cl- net absorption, 36Cl- unidirectional fluxes were detected under similar experimental conditions. The Cl- net flux mean value was 0.11 +/- 0.02 microE.cm-2.h-1 (316 experiments) which accounts for 70% of the discrepancy between the Na+ net flux and short circuit current. This Cl- net absorption occurred in the absence of electrochemical gradients and was very likely maintained by a Na+/K+/2Cl- cotransport located at the outermost membrane of the epithelium. In fact bumetanide challenge (10(-5) M in the external fluid) strongly inhibited 36Cl- influx and 22Na+ influx across this tissue and cleared off the discrepancy between short circuit current and sodium net flux.

Effect of calcitonin gene-related peptide on sodium absorption through isolated skin of Rana esculenta.

Calcitonin gene-related peptide (CGRP) added to the internal fluid bathing the isolated skin of Rana esculenta strongly stimulates the active sodium absorption. This action is dose-dependent, the dose eliciting the maximal effect being 2 . 10(-7) M; alpha and beta CGRP exhibit the same potency. The CGRP action on sodium transport is mainly due to its interaction with CGRP1 receptors, since it is inhibited by CGRP8-37, its specific antagonist. The second messengers probably involved in the action of CGRP are cAMP and Ca+2, since this action is reduced by SQ22536 and W7, which are inhibitors of adenyl cyclase and calmodulin respectively. On the contrary, inhibitors of protein kinase C (1-O-hexadecyl-2-O-methyl-sn-glycerol) and nitric oxide synthase (L-NAME) do not modify the action on sodium transport. ETYA, an inhibitor of all the metabolic pathways of arachidonic acid, decreases the CGRP action by 38%. In order to search for the arachidonic acid metabolites involved in the CGRP action, the effect of the following inhibitors was tested: aspirin and naproxen (for cyclooxygenases), NDGA (for cyclooxygenases), NDGA (for lipoxygenases) clotrimazole (for epoxygenases). None of these substances is able to inhibit the CGRP action on sodium transport. Moreover, adding arachidonic acid inhibits the CGRP action, but this effect was also obtained by another unsaturated fatty acid, oleic acid. Since unsaturated fatty acids are able to inhibit the protein kinase A, these results indirectly support the role of cAMP as a second messenger of the CGRP action on sodium transport.

Cyclosporin A stimulates Na+ transport across the isolated skin of Rana esculenta.

Cyclosporin A (Cs A), added to the fluid bathing the internal surface of the isolated skin of Rana esculenta, increased short-circuit current (SCC) with a maximal effect at 5 microM. This effect was completely inhibited by amiloride (0.2 mM in the fluid bathing the external surface). By measuring both transepithelial fluxes of 22Na+ across symmetrical parts of the short circuited skin, Cs A was found to increase the net absorption of Na+. Naproxen (10 microM), a cyclooxygenase inhibitor, decreased the stimulation by Cs A of SCC, suggesting that in this stimulation prostaglandins are involved. The Cs A effect on Na+ transport could be caused by an inhibition of a Ca2+/calmodulin-dependent protein phosphatase, i.e. calcineurin, since: a) it is mimicked by another inhibitor of calcineurin, i.e. fenvalerate: b) the action of Cs A and fenvalerate on SCC are decreased by the calmodulin inhibitor W7.

15q11.2 microdeletion - seven new patients with delayed development and/or behavioural problems.

15q11.2 microdeletion has been suggested as a new microdeletion syndrome and several patients have been described in the literature. We report seven new patients belonging to six families, age 9-24 years old, with a 350 kb 15q11.2 deletion of the four highly conserved genes (TUBGCP5, NIPA1, NIPA2 and CYFIP1) earlier reported. All our patients had some degree of learning difficulties, delayed development and/or behavioural problems. Common dysmorphic features and congenital malformations were not characteristics of our patients. The deletion was inherited from a mildly affected parent in all cases tested (5/6 families available for testing both parents). These seven new cases confirm some of the features earlier reported to be associated with 15q11.2 deletion, and help to further delineate the phenotype associated with 15q11.2 deletion.

Action of forskolin on non-electrolyte permeability across the urinary bladder of Bufo bufo as compared to that of various hormones.

1. Forskolin, an activator of adenyl-cyclase in a receptor-independent manner, mimics the ADH effect on the urea and thiourea permeabilities across the toad bladder. 2. However, differently from ADH, forskolin increases the erythritol permeability across the tissue and this effect is not reproduced by two substances increasing the urea permeability (8-BrcAMP and isoprenaline). Most probably this effect of forskolin does not involve the cAMP generating system.

Effect of reagents of protein functional groups on the ADH-induced urea facilitated transport across toad urinary bladder.

1--The mechanism of the vasopressin-induced, facilitated transport across toad urinary bladder was studied by treating the luminal membrane of the epithelium with the following reagents of protein functional groups: NEM (SH groups), SITS (amino groups), EEDQ (carboxylic groups), DEPC (histidine). 2--Treatment of the luminal side of the epithelium by NEM strongly inhibits the ADH-induced urea transport, leaving unmodified the effect of the hormone on the flux of antipyrine, a lipid soluble molecule. These results confirm the hypothesis that the urea carrier is of proteic nature. 3--Treatment of the luminal side by SITS strongly inhibits ADH action on urea and antipyrine permeability; thus this effect can be considered rather unspecific. 4--On the contrary the EEDQ effect is more specific; in fact treatment of the luminal side by EEDQ strongly inhibits ADH effect on the permeability of urea, slightly increasing the ADH effect on that of antipyrine. 5--Finally, the luminal treatment by diethylpyrocarbonate inhibits almost completely the ADH action on the urea fluxes, slightly increasing the hormone effect on the antipyrine ones. 6--Based on these results we conclude that carboxylic groups and the imidazolic ring are more important than the amino groups in determining the urea transport across toad bladder, in the presence of ADH.

Permeability properties of the Bufo bufo bladder as affected by isoprenaline and vasopressin.

Isoprenaline, a beta adrenergic agonist, strongly increases both transepithelial fluxes across the urinary bladder of Bufo bufo; this effect is dose dependent, 10(-6)M being necessary for the maximal action. This effect is less selective than that of vasopressin: the ratio J urea/J thiourea is 3.8 under isoprenaline and 30.4 under vasopressin treatment. Both hormones differently affect the permeability of a mainly liposoluble molecule, i.e. antipyrine: vasopressin increases antipyrine permeability, while isoprenaline decreases it. Moreover diethylpyrocarbonate treatment of the luminal membrane strongly inhibits vasopressin effect on urea permeability leaving unmodified that of isoprenaline. However, the actions of both hormones are not additive. These results allows to assume that the tissue has a feedback mechanism which inhibits other hormonal action while the bladder is stimulated by a particular hormone.

Effect of vasopressin on the permeability of non electrolytes across the skins of Rana esculenta and Bufo bufo.

Maximal doses of vasopressin increase the permeability of the skins of Bufo bufo and Rana esculenta to urea, ethylene glycol, glycerol, erythritol, beta-alanine, leaving virtually unmodified that of mannitol and antipyrine. These results demonstrate that the response to vasopressin is quite different in amphibian skins as compared to the bladders. A careful analysis of the effects of vasopressin on non-electrolyte permeability as a function of their molecular weight demonstrates that hormone elicits the formation of pores with a diameter inferior to 4 A. Under vasopressin treatment the skins exhibit a selectivity for polyhydroxylated molecules as compared to urea and beta-alanine. This selectivity is not due to active of facilitated transport and is not impaired by phloretin or DTNB which selectively blocks the permeability of urea or ethylene glycol in erythrocytes. It is proposed that the site of such selectivity is located in other plasma membranes of the epithelium.