Cloning of a receptor for amphibian [Phe13]bombesin distinct from the receptor for gastrin-releasing peptide: identification of a fourth bombesin receptor subtype (BB4).

Bombesin is a tetradecapeptide originally isolated from frog skin and demonstrated to have a wide range of actions in mammals. Based on structural homology and similar biological activities, gastrin-releasing peptide (GRP) has been considered the mammalian equivalent of bombesin. We previously reported that frogs have both GRP and bombesin, which therefore are distinct peptides. We now report the cloning of a bombesin receptor subtype (BB4) that has higher affinity for bombesin than GRP. PCR was used to amplify cDNAs related to the known bombesin receptors from frog brain. Sequence analysis of the amplified cDNAs revealed 3 classes of receptor subtypes. Based on amino acid homology, two classes were clearly the amphibian homologs of the GRP and neuromedin B receptors. The third class was unusual and a full-length clone was isolated from a Bombina orientalis brain cDNA library. Expression of the receptor in Xenopus oocytes demonstrated that the receptor responded to picomolar concentrations of [Phe13]-bombesin, the form of bombesin most prevalent in frog brain. The relative rank potency of bombesin-like peptides for this receptor was [Phe13]bombesin > [Leu13]bombesin > GRP > neuromedin B. In contrast, the rank potency for the GRP receptor is GRP > [Leu13]bombesin > [Phe13]bombesin > neuromedin B. Transient expression in CHOP cells gave a Ki for [Phe13]bombesin of 0.2 nM versus a Ki of 2.1 nM for GRP. Distribution analysis showed that this receptor was expressed only in brain, consistent with the distribution of [Phe13]-bombesin. Thus, based on distribution and affinity, this bombesin receptor is the receptor for [Phe13]bombesin. Phylogenetic analysis suggests that this receptor separated prior to separation of the GRP and neuromedin B receptors; thus, BB4 receptors and their cognate ligands may also exist in mammals.

A Xenopus distal-less gene in transgenic mice: conserved regulation in distal limb epidermis and other sites of epithelial-mesenchymal interaction.

In this paper, we show the conserved regulation of the homeodomain gene Distal-less-3 (Dlx-3) by analyzing the expression of a promoter from the Xenopus ortholog, Xdll-2, in transgenic mice. A 470-bp frog regulatory sequence confers appropriate expression on a lacZ reporter gene in the ectodermal component of structures derived from epithelial-mesenchymal interactions. Remarkably, this includes structures absent in Xenopus, such as the hair follicle and mammary gland, suggesting that conserved regulatory elements can be used to control the formation of structures peculiar to individual species. In addition, expression of Dlx-3 in developing limbs is highest at the most distal portion. This pattern is duplicated by the Xenopus promoter, indicating that this DNA may include sequences responsive to conserved proximodistal patterning signals in the vertebrate limb.

Adaptive plasticity in hatching age: a response to predation risk trade-offs.

The life histories of many animals are characterized by niche shifts, the timing of which can strongly affect fitness. In the tree frog Agalychnis callidryas, which has arboreal eggs, there is a trade-off between predation risks before and after hatching. When eggs are attacked by snakes, tadpoles escape by hatching rapidly and falling into the water below. Eggs not attacked by snakes hatch later, when newly emerged tadpoles are less vulnerable to aquatic predators. Plasticity in hatching allows embryos to use immediate, local information on risk of mortality to make instantaneous behavioral decisions about hatching and the accompanying shift from arboreal to aquatic habitats.

Oxidação eletroquímica de etanol em temperatura ambiente e intermediária: estudo quantitativo das vias reacionais por espectrometria de massas on-line

Na primeira parte do trabalho, foram investigados materiais ativos para eletro-oxidar etanol e acetaldeído seletivos para a rota C2 (Carbono 2) e, também, ativos para eletro-oxidar hidrogênio molecular, visando a aplicação em células a combustível de hidrogênio indireto. Neste tipo de célula, um processador de combustível externo desidrogena o etanol e os produtos desta reação, contendo H2, acetaldeído e, possivelmente, etanol residual, são direcionados para alimentar o ânodo. Neste sentido, o eletrocatalisador anódico pode ser ativo para a eletro-oxidação de etanol residual, bem como acetaldeído, mas este deve catalisar a reação via C2 com o objetivo de evitar a formação de espécies que envenenam a superfície catalítica (CO ou CHx), ou seja, a ligação C-C deve permanecer intacta. Os eletrocatalisadores bimetálicos foram formados por M/Pt/C (onde M = W, Ru ou Sn) e os produtos reacionais foram analisados por DEMS On-line. Os resultados mostraram que Ru/Pt/C e Sn/Pt/C apresentaram maiores taxas de reação global, no entanto, eles não foram seletivos. Por outro lado, W2/Pt3/C foi mais seletivo para a rota C2, dada a não formação de CH4 e CO2. Além disso, este material também foi ativo e estável para a eletro-oxidação de H2, mesmo na presença de acetaldeído, o que o torna um potencial catalisador para aplicação no ânodo de células a combustível de hidrogênio indireto. Na segunda parte do trabalho, o objetivo foi relacionado com o estudo de eletrocatalisadores seletivos para a rota C1 (Carbono 1). A oxidação eletroquímica do etanol e de seus produtos reacionais foram investigados por DEMS on-line em temperatura ambiente e intermediária (245oC). Para temperatura ambiente, utilizou-se solução aquosa de ácido sulfúrico (H2SO4) e, para temperatura intermediária, utilizou-se ácido sólido (CsH2PO4) como eletrólito. Os eletrocatalisadores investigados foram formados por SnOxRuOx-Pt/C e Pt/C. Em temperatura ambiente, os resultados de polarização potenciodinâmica mostraram uma maior atividade eletrocatalítica para o material SnOxRuOx-Pt/C, com eficiência de corrente para formação de CO2 de 15,6% contra 15,2% para Pt/C, sob condições estagnantes, sem controle por transporte de massa. O stripping de resíduos reacionais, após a eletro-oxidação de etanol bulk, sob condições de fluxo, mostraram o acúmulo de espécies com 1 átomo de carbono (CO e CHx) que causam o bloqueio dos sítios ativos e são oxidadas eletroquimicamente somente em mais altos potenciais (ca. 1,0 V). Por outro lado, as curvas de polarização a 245oC mostraram maiores valores de eficiências de correntes para formação de CO2 (45% para Pt/C em ambos potenciais 0,5 V e 0,8 V contra 36% e 50% para SnOxRuOx-Pt/C em 0,5 V e 0,8 V respectivamente) quando comparado com os valores obtidos em temperatura ambiente, mas com atividades similares para SnOxRuOx-Pt/C e Pt/C. Para ambos os eletrocatalisadores, os estudos de espectrometria de massas a 245oC evidenciaram que as rotas eletroquímicas ocorrem em paralelo com rotas puramente químicas, envolvendo catálise heterogênea, de decomposição do etanol, produzindo H2 e CO2 como produtos majoritários.

Sulfur resistance of Pt-W catalysts

The sulfur resistance of low-loaded monometallic Pt catalysts and bimetallic Pt-W catalysts during the partial selective hydrogenation of styrene, a model compound of Pygas streams, was studied. The effect of metal impregnation sequence on the activity and selectivity was also evaluated. Catalysts were characterized by ICP, TPR, XRD, and XPS techniques. Catalytic tests with sulfur-free and sulfur-doped feeds were performed. All catalysts showed high selectivities (>98%) to ethylbenzene. Activity differences between the catalysts were mainly attributed to electronic effects due to the presence of different electron-rich species of Pt0 and electron-deficient species of Ptδ+. Pt0 promotes the cleavage of H2 while Ptδ+ the adsorption of styrene. The catalyst successively impregnated with W and Pt (WPt/Al) was more active and sulfur resistant than the catalyst prepared with an inverse impregnation order (PtW/Al). The higher poison resistance of WPt/Al was attributed to both steric and electronic effects.

Identification of YAP as sperm-PAWP’s predominant binding partner in MII-arrested oocytes and the relevance of this WWI domain modular interaction to oocyte activation

PAWP, a candidate sperm-borne oocyte activating factor, induces oocyte activation and acts upstream of the calcium signalling pathway, however, PAWP’s downstream signalling pathway in oocyte cytoplasm remains to be uncovered. Data from our lab suggested that the interacting partner of PAWP, at least in the frog (Xenopus laevis) model may be YAP, a highly expressed protein in amphibian and mammalian oocytes. Therefore, the objectives of this study were to confirm that PAWP’s predominant binding partner in Xenopus laevis oocyte is YAP; to determine if mammalian oocyte activation is also dependent on PAWP-YAP interaction; and to verify that the PAWP-YAP interaction during oocyte activation is dependent on the WWI domain module. By immunohistochemistry, YAP was localized predominantly in the cytosol of metaphase II-arrested Xenopus laevis oocytes, where presumably the PAWP-YAP interaction occurs. Utilizing Far Western blotting, YAP was identified as the predominant binding partner of PAWP, in metaphase II-arrested frog (Xenopus laevis), swine (Sus scrofa) and mouse (mus musculus) oocytes. The specificity of this interaction was then tested on Far Western blotting of mouse ovarian and oocyte cytosolic extracts, by competition with both wild-type and point-mutated recombinant WWI domains derived from YAP. The removal of GST from the wild-type WWI-GST fusion protein was a requirement for effective blockage of WWI module interaction between PAWP and YAP. As expected, the mutated WWI domain was ineffective in inhibiting the PAWP-YAP interaction. To conclude, this study identified YAP as the predominant binding partner of PAWP in both amphibian and mammalian oocytes, and showed this interaction is dependent on the WWI modular interaction. The results allow us to test the functional relevance of this WWI modular interaction during oocyte activation in vivo, in the future.

In defense of Harriet Shelley : and other essays /

In defense of Harriet Shelley.--Fenimore Cooper's literary offenses.--Traveling with a reformer.--Private history of the "Jumping frog" story.--Mental telegraphy.--Mental telegraphy again.--What Paul Bourget thinks of us.--A little note to M. Paul Bourget.--The invalid's story.--Stirring times in Austria.--The German Chicago.--Concerning the Jews.--About all kinds of ships.--From the "London times" of 1904.--A majestic literary fossil.--At the appetite cure.--Saint Joan of Arc.--In memoriam.--A biographical sketch.

Ezra Hardman, M.A., of Wayback College, and other stories,

Ezra Hardman, M.A.--The light of circumstance.--Sylvia Graham Kimberton.--The giant's strength.--The crime of Lois Baxter.--In poverty row.--The Chevalier d'Artois.--Her son.--Poison flowers.

Our Jenny : a story for young people /

Wood engravings: frontispiece, ills., title vignette.

How to tell a story, and other essays /

How to tell to a story -- In defence of Harriet Shelley --Fenimore Cooper's literary offences -- Travelling with a reformer -- Private history of the "jumping frog" story -- Mental telegraphy again -- What Paul Bourget thinks of us -- A little note to M. Paul Bourget.

Histories extraordinaries /

Primera serie. Ligeia. -- Eleonora. -- Berenice. -- Morella. -- La caiguda de la casa Usher. -- El retrat oval. -- William Wilson. -- La mascara de la mort roja. -- El rei pesta. -- El pou 1 el Pèndol. -- Segona serie. El gat negre. -- El cor delator. -- El barril d'amontillado. -- Hop. -- Frog. -- Metzengerstein en el cas de M. Valdemar. -- L'illa de la fada. -- El poder de les paraules. -- Conversa d'Eiros i Charmion. -- Col·Lo-qui de monos i una. -- Uns quants mots amb una monia.

How to tell a story, and other essays.

How to tell a story.--In defence of Harriet Shelley.--Fenimore Cooper's literary offences.--Travelling with a reformer.--Private history of the "jumping frog" story.--Mental telegraphy again.--What Paul Bourget thinks of us.--A little note to M. Paul Bourget.

Polish fairy tales /

Selections from the author's "Bajarz polski" published at Wilna in 1862.