Liddle's syndrome caused by a novel missense mutation (P617L) of the epithelial sodium channel beta subunit.

OBJECTIVE: The aim of the study was to search for mutations of SCNN1B and SCNN1G in an Italian family with apparently dominant autosomal transmission of a clinical phenotype consistent with Liddle's syndrome. METHODS: Genetic analysis was performed in the proband, his relatives, and 100 control subjects. To determine the functional role of the mutation identified in the proband, we expressed the mutant or wild-type epithelial sodium channel in Xenopus laevis oocytes. RESULTS: A novel point mutation, causing an expected substitution of a leucine residue for the second proline residue of the conserved PY motif (PPP x Y) of the beta subunit was identified in the proband. The functional expression of the mutant epithelial sodium channel in X. laevis oocytes showed a three-fold increase in the amiloride-sensitive current as compared with that of the wild-type channel. CONCLUSION: This newly identified mutation adds to other missense mutations of the PY motif of the beta subunit of the epithelial sodium channel, thus confirming its crucial role in the regulation of the epithelial sodium channel. To our knowledge, this is the first report of Liddle's syndrome in the Italian population, confirmed by genetic and functional analysis, with the identification of a gain-of-function mutation not previously reported.

Homologous DNA pairing domain peptides of RecA protein: intrinsic propensity to form beta-structures and filaments.

The 20 amino acid residue peptides derived from RecA loop L2 have been shown to be the pairing domain of RecA. The peptides bind to ss- and dsDNA, unstack ssDNA, and pair the ssDNA to its homologous target in a duplex DNA. As shown by circular dichroism, upon binding to DNA the disordered peptides adopt a beta-structure conformation. Here we show that the conformational change of the peptide from random coil to beta-structure is important in binding ss- and dsDNA. The beta-structure in the DNA pairing peptides can be induced by many environmental conditions such as high pH, high concentration, and non-micellar sodium dodecyl sulfate (6 mM). This behavior indicates an intrinsic property of these peptides to form a beta-structure. A beta-structure model for the loop L2 of RecA protein when bound to DNA is thus proposed. The fact that aromatic residues at the central position 203 strongly modulate the peptide binding to DNA and subsequent biochemical activities can be accounted for by the direct effect of the aromatic amino acids on the peptide conformational change. The DNA-pairing domain of RecA visualized by electron microscopy self-assembles into a filamentous structure like RecA. The relevance of such a peptide filamentous structure to the structure of RecA when bound to DNA is discussed.

Mécanisme moléculaire de protection des HDLs contre le stress du réticulum endoplasmique dans la cellule beta pancréatique. [Molecular mechanisms of HDLs to protect against the endoplasmic reticulum stress in pancreatic beta cell.]

Introduction: Les particules de HDL (High Density Lipoproteins) ont des fonctions très diverses notamment anti-inflamatoires, anti-apoptotiques ou anti-oxydatives. Chez les patients diabétiques, les niveaux de HDLs sont bas, les prédisposants ainsi à un risque élévé à développer une maladie cardiovasculaire. Sachant que le s HDLs ont également un effet protecteur sur la cellule beta, le but de cette étude est dinvestigué les mécanismes moléculaires de cette protection contre le stress du réticulum, stress qui contriubue au développement du diabéte de type 2. Résultats: La thapsigargine et la tunicamycine induisent lapoptose en induisant un stress dans le réticulum endoplasmique (RE) par un mauvais repliement des protéines dans le RE, ainsi que l'activation de l'UPR (Unfolded Protein Respons) avec trois voies communes de signalisation intracellulaire (IRE1, PREK et ATF6). Ces voix veillent tout d'abord à augmenter la capacité de repliement des protéines et le cas échéant à lapoptose. Nos résultats montrent que les HDLs sont capable d'inhuber lapoptose induite par la thapsigargine et la tunicamycine dans les MIN6. Dans le cas du traitement avec la thapsigargine, plusieurs marqueurs des voix UPR sont bloqués en présence des HDLs, suggérant que l'effet anti-apoptotiques des HDLs s'exerce au niveau ou en amont du RE. Les HDLS par contre ne bloquent par la sortie de calcium du RE induite par la thapsigargine ce qui indique que les HDLs n'interfèrent pas avec l'action de cette drogue sur sa cible (SERCA). Dans le cas de la la tunicamycine, les HDLs ne bloquent pas, ou très légèrement, l'activation des voix de l'UPR. La protection induite par les HDLs contre la mort engendrée par la tunicamycine s'sexerce dont apparement en aval de l'UPR et reste à être déterminer. Conclusions: Nos données suggérent que les HDLs sont capable de protéger la cellule beta contre le stress du réticulum mais apparement de façon différente selon les modalités d'inductions de ce stress.

The complete amino acid sequence for brain beta spectrin (beta fodrin): relationship to globin sequences.

The amino acid sequence of mouse brain beta spectrin (beta fodrin), deduced from the nucleotide sequence of complementary DNA clones, reveals that this non-erythroid beta spectrin comprises 2363 residues, with a molecular weight of 274,449 Da. Brain beta spectrin contains three structural domains and we suggest the position of several functional domains including f-actin, synapsin I, ankyrin and spectrin self association sites. Analysis of deduced amino acid sequences indicated striking homology and similar structural characteristics of brain beta spectrin repeats beta 11 and beta 12 to globins. In vitro analysis has demonstrated that heme is capable of specific attachment to brain spectrin, suggesting possible new functions in electron transfer, oxygen binding, nitric oxide binding or heme scavenging.

Lycaenid caterpillars (Lepidoptera, Lycaenidae) eating flowers of Dalea pennellii var. chilensis (Fabaceae) in the northern Chilean Andes

Lycaenid caterpillars (Lepidoptera, Lycaenidae) eating flowers of Dalea pennellii var. chilensis (Fabaceae) in the northern Chilean Andes. The shrub Dalea pennellii var. chilensis (Fabaceae) is reported for the first time as a host plant for three Neotropical Polyommatini (Lepidoptera, Lycaenidae, Polyommatinae): Hemiargus ramon (Dognin, 1887), Leptotes trigemmatus (Butler, 1881) and Nabokovia faga (Dognin, 1895), based on two collections performed in the western slopes of the northern Chilean Andes in two consecutive summers. The relative abundance was always above 90% for N. faga while it was always less than 5% for H. ramon and L. trigemmatus. Furthermore, N. faga was not found on inflorescences of other native Fabaceae examined in the study site. This pattern suggests a close relationship between N. faga and D. pennellii var. chilensis, at least at a local scale.

Manganese-induced integrin affinity maturation promotes recruitment of alpha V beta 3 integrin to focal adhesions in endothelial cells: evidence for a role of phosphatidylinositol 3-kinase and Src.

Integrin activity is controlled by changes in affinity (i.e. ligand binding) and avidity (i.e. receptor clustering). Little is known, however, about the effect of affinity maturation on integrin avidity and on the associated signaling pathways. To study the effect of affinity maturation on integrin avidity, we stimulated human umbilical vein endothelial cells (HUVEC) with MnCl(2) to increase integrin affinity and monitored clustering of beta 1 and beta 3 integrins. In unstimulated HUVEC, beta 1 integrins were present in fibrillar adhesions, while alpha V beta 3 was detected in peripheral focal adhesions. Clustered beta 1 and beta 3 integrins expressed high affinity/ligand-induced binding site (LIBS) epitopes. MnCl(2)-stimulation promoted focal adhesion and actin stress fiber formation at the basal surface of the cells, and strongly enhanced mAb LM609 staining and expression of beta 3 high affinity/LIBS epitopes at focal adhesions. MnCl(2)-induced alpha V beta 3 clustering was blocked by a soluble RGD peptide, by wortmannin and LY294002, two pharmacological inhibitors of phosphatidylinositol 3-kinase (PI 3-K), and by over-expressing a dominant negative PI 3-K mutant protein. Conversely, over-expression of active PI 3-K and pharmacological inhibiton of Src with PP2 and CGP77675, enhanced basal and manganese-induced alpha V beta 3 clustering. Transient increased phosphorylation of protein kinase B/Akt, a direct target of PI 3K, occurred upon manganese stimulation. MnCl(2) did not alter beta 1 integrin distribution or beta1 high-affinity/LIBS epitope expression. Based on these results, we conclude that MnCl(2)-induced alpha V beta 3 integrin affinity maturation stimulates focal adhesion and actin stress fiber formation, and promotes recruitment of high affinity alpha V beta 3 to focal adhesions. Affinity-modulated alpha V beta 3 clustering requires PI3-K signaling and is negatively regulate by Src.

The taxonomic identity of Heliconius melpomene f. pyritosa var. fumigata Zikán (Lepidoptera: Nymphalidae)

The taxonomic identity of the butterfly Heliconius melpomene f. pyritosa var. fumigata Zikán, 1937 (Nymphalidae: Heliconiinae) is discussed based on the discovery of the specimen based on which this name was assigned. The specimen is not a variation of Eueides tales surdus Stichel, 1903, as previously stated, but is in fact a variation of H. melpomene f. pyritosa, which is a synonym of Heliconius erato amalfreda Riffarth, 1901.

Beta-ionone attracts Euglossa mandibularis(Hymenoptera, Apidae) males in western Paraná forests

ABSTRACTMales of Euglossa mandibularis were consistently captured in scent traps baited with β-ionone in areas of Mixed Ombrophylous Forests or transition between this latter physiognomy and Montane Semideciduous Forest at Parque Nacional do Iguaçu, Paraná state, Brazil. Geographic records for the species and sampling effort (including or not β-ionone among the offered compounds) along Atlantic Forest biome are presented and discussed. We also discuss seasonal and geographic variation in collection of scents by orchid bees.

Estudio sobre las adaptaciones de los artrópodos a la vida en las lomas de los alrededores de Lima

Observaciones periódicas de las fluctuaciones de la temperatura en la superficie del suelo y a diversos niveles hasta 30 cm. encima y debajo de ésta, es decir, del microclima, en el cual cumple su ciclo biológico la gran mayoría de los componentes de la fauna de las lomas. Como se aprecia en las láminas II y III, se limita el invierno constantemente frío a los meses de Junio a Agosto, o en otros años de Julio a Setiembre. Los meses de Mayo y Setiembre, respectivamente Octubre, se caracterizan por los abruptos cambios en que alternan días calientes veraniegos con los días fríos invernales. Días soleados y de temperaturas constantemente altas caracterizan la época de Verano en los meses de Noviembre hasta Abril. Las temperaturas diurnas mayores (65°C) se obtuvo en la superficie del suelo en Marzo y las temperaturas diurnas menores (18.5°C) en Julio. Durante todo el curso de un día de Invierno nublado, las temperaturas se mantenían con escasa variación entre 13°C y 18°C en los seis niveles observados sobre y bajo la superficie del suelo. Variando menos y siendo más altas en las capas más profundas (Lámina I). Las correspondientes observaciones para un día de Verano mostraron (Lámina I) que las temperaturas pueden variar en la superficie entre 19°C y 53°C, mientras a esta diferencia de 34°C correspondía a sólo 30 cm. bajo el suelo una temperatura casi constante, con una diferencia de solo 2°C, entre máxima de 33°C y mínima de 31°C. Relacionándose la vida animal en las lomas estrechamente con la vida vegetal, la fauna es más abundante en el invierno. En total se han registrado 256 especies de artrópodos; el 26% de los cuales son coleópteros, el 20% dípteros, el 12% himenópteros, el 9% lepidópteros; el 7% son Araneida y el 0.8% Scorpionida. Especie típicas del arenal con vegetación son : el escorpión Brachistosternus ehrenbergi GERVAIS, la araña Sicarius peruensis KEYS, el lepismátido Acrotelsella gigantea ESCHERICH, los tenebrionidos Scotobious vulgaris GUERIN, Psametichus costatus GUERIN y Philorea mucronata SESN., dos especies de Ántrax (BombyliidaeDipt.) y la abeja Caupolicana vestita var. Piurensis CKLL. Que anida sólo en el suelo arenoso.

Estructura y composición de la comunidad macrobentónica asociada a la macroalga filamentosa Chaetomorpha crassa en el submareal somero de la Isla San Lorenzo, Callao - Perú

El presente estudio tuvo como objetivo caracterizar la comunidad macrobentónica asociada a la macroalga filamentosa Chaetomorpha crassa, diferenciando la comunidad que habita en los filamentos del parche y en el sustrato subyacente y adyacente al parche, en el submareal somero de la Isla San Lorenzo – Callao. Los muestreos se realizaron en un parche de Ch. crassa ubicado entre los 5 y 7 m. de profundidad, al este de Isla San Lorenzo (12°04’10.6’’ S; 77°13’13.8’’ W - 12°04’12.4’’ S; 77°13’13’’ W), en dos estaciones anuales (invierno y verano) entre los años 2013 y 2015. Los muestreos se distribuyeron cronológicamente de la siguiente manera: agosto de 2013: invierno 1 (I-1), diciembre de 2013: verano 1 (V-1), julio de 2014: invierno 2 (I-2) y marzo de 2015: verano 2 (V-2). En cada muestreo se colectaron muestras de los filamentos de Ch. crassa (AP), el sustrato subyacente al parche (AS) y el sustrato adyacente al parche (C) (n=10). Cada muestra fue procesada en el laboratorio, para la determinacion taxonómica de las taxa y el registro del número de individuos y peso húmedo por taxa. En todas las estaciones, los hábitats estudiados albergaron una gran diversidad y abundancia de especies, siendo los filamentos de Ch. crassa los que presentaron mayor diversidad y abundancia promedio, mientras que el sustrato subyacente al parche de Ch. crassa presentó los menores valores de diversidad y abundancia promedio. Asimismo se encontraron diferencias estacionales en la comunidad macrobentónica del submareal somero de la Isla San Lorenzo, estas diferencias tambien fueron observadas, aunque de manera particular, en la comunidad asociada a los filamentos y al sustrato subyacente al parche de Ch. crassa. Por lo tanto, los resultados sugieren que la macroalga filamentosa Chaetomorpha crassa estaría funcionando como un organismo estructurador de hábitat en el submareal somero de la Isla San Lorenzo. Palabras clave: Chaetomorpha crassa, comunidad macrobentónica, hábitat, diversidad, abundancia, Isla San Lorenzo.

Gene deletion of dopamine beta-hydroxylase and alpha1-adrenoceptors demonstrates involvement of catecholamines in vascular remodeling.

In vitro studies have shown that stimulation of alpha1-adrenoceptors (ARs) directly induces proliferation, hypertrophy, and migration of arterial smooth muscle cells and adventitial fibroblasts. In vivo studies confirmed these findings and showed that catecholamine trophic activity becomes excessive after experimental balloon injury and contributes to neointimal growth, adventitial thickening, and lumen loss. However, past studies have been limited by selectivity of pharmacological agents. The aim of this study, in which mice devoid of norepinephrine and epinephrine synthesis [dopamine beta-hydroxylase (DBH-/-)] or deficient in alpha1-AR subtypes expressed in murine carotid (alpha1B-AR-/- and alpha1D-AR-/-) were used, was to test the hypothesis that catecholamines contribute to wall hypertrophy after injury. At 3 wk after injury of wild-type mice, lumen area and carotid circumference increased significantly, and hypertrophy of media and adventitia was in excess of that needed to restore circumferential wall stress to normal. In DBH-/- and alpha1B-AR-/- mice, increases in lumen area, circumference, and hypertrophy of the media and adventitia were reduced by 50-91%, resulting in restoration of wall tension to nearly normal (DBH-/-) or normal (alpha1B-AR-/-). In contrast, in alpha1D-AR-/- mice, increases in lumen area, circumference, and wall hypertrophy were unaffected and wall thickening remained in excess of that required to return tension to normal. When examined 5 days after injury, proliferation and leukocyte infiltration were inhibited in DBH-/- mice. These studies suggest that the trophic effects of catecholamines are mediated primarily by alpha1B-ARs in mouse carotid and contribute to hypertrophic growth after vascular injury.

Differentiation of trophoblast giant cells and their metabolic functions are dependent on peroxisome proliferator-activated receptor beta/delta.

Mutation of the nuclear receptor peroxisome proliferator-activated receptor beta/delta (PPARbeta/delta) severely affects placenta development, leading to embryonic death at embryonic day 9.5 (E9.5) to E10.5 of most, but not all, PPARbeta/delta-null mutant embryos. While very little is known at present about the pathway governed by PPARbeta/delta in the developing placenta, this paper demonstrates that the main alteration of the placenta of PPARbeta/delta-null embryos is found in the giant cell layer. PPARbeta/delta activity is in fact essential for the differentiation of the Rcho-1 cells in giant cells, as shown by the severe inhibition of differentiation once PPARbeta/delta is silenced. Conversely, exposure of Rcho-1 cells to a PPARbeta/delta agonist triggers a massive differentiation via increased expression of 3-phosphoinositide-dependent kinase 1 and integrin-linked kinase and subsequent phosphorylation of Akt. The links between PPARbeta/delta activity in giant cells and its role on Akt activity are further strengthened by the remarkable pattern of phospho-Akt expression in vivo at E9.5, specifically in the nucleus of the giant cells. In addition to this phosphatidylinositol 3-kinase/Akt main pathway, PPARbeta/delta also induced giant cell differentiation via increased expression of I-mfa, an inhibitor of Mash-2 activity. Finally, giant cell differentiation at E9.5 is accompanied by a PPARbeta/delta-dependent accumulation of lipid droplets and an increased expression of the adipose differentiation-related protein (also called adipophilin), which may participate to lipid metabolism and/or steroidogenesis. Altogether, this important role of PPARbeta/delta in placenta development and giant cell differentiation should be considered when contemplating the potency of PPARbeta/delta agonist as therapeutic agents of broad application.

Produtividade e qualidade de sementes de feijoeiro (Phaseolus vulgaris L.) sob influência de parcelamentos e fontes de nitrogênio

O presente trabalho objetivou avaliar o efeito de fontes e do parcelamento de nitrogênio na produtividade do feijão "de inverno" e na qualidade fisiológica e uniformidade de suas sementes. O experimento foi instalado em área pertencente à Faculdade de Engenharia de Ilha Solteira - UNESP, no período de inverno. Foram estudados 14 tratamentos, constituídos por duas fontes de N (sulfato de amônio e uréia) e sete parcelamentos (0-0; 0-75; 15-60; 30-45; 45-30; 60-15 e 75-0 kg ha-1 de N, respectivamente, na semeadura e em cobertura). Toda a área experimental recebeu 60 kg ha-1 de P2O5 e 30 kg ha-1 de K2O como adubação básica. A qualidade fisiológica das sementes foi avaliada por meio do teste de germinação e testes de vigor. A aplicação de 75 kg ha-1 de nitrogênio propiciou, em média, incrementos de 38% na produtividade da cultura. O nitrogênio na semeadura e, ou, em cobertura não interferiu na produtividade do feijoeiro. Nas condições experimentais, a adubação com uréia e exclusivamente na semeadura seria a recomendada, tendo em vista uma única aplicação e a produtividade obtida. A aplicação de nitrogênio proporcionou a obtenção de maior quantidade de sementes comerciais, não sendo o modo de aplicação e a fonte consistentes quanto aos seus efeitos sobre o vigor das sementes.

Efeito de três manejos do lençol freático na adaptação fisiomorfológica do feijoeiro (Phaseolus vulgaris, L.) ao encharcamento

Estudou-se o efeito de três manejos do lençol freático na indução de adaptações fisiomorfológicas do cultivar Bat 477 de feijão (Phaseolus vulgaris, L.) à hipoxia, com vistas em caracterizar a influência relativa dos principais fatores físicos, químicos e biológicos interferentes. O experimento foi realizado em campo, na ESALQ/USP, Piracicaba (SP), de março a junho de 1999, utilizando-se caixas de cimento amianto de 1.000 L como unidade experimental no delineamento de parcelas inteiramente ao acaso, com quatro tratamentos e cinco repetições. As caixas receberam estrutura própria de manejo e controle do lençol freático. Simulou-se ao máximo um meio físico/condição natural de uma várzea. Após a indução no período vegetativo, a eficiência dos manejos foi testada pela inundação temporária do solo no fim do florescimento/formação de vagens. Houve um efetivo processo de nodulação das raízes, a despeito da condição de alta saturação do solo. As características biométricas de crescimento, embora acusando prejuízo da hipoxia, evidenciaram a utilização pela planta de mecanismos adaptativos morfológicos (raízes adventícias e lenticelas), biológicos (fixação de N) e fisiomorfológicos (resistividade estomática e transpiração). Já as características biométricas de colheita evidenciaram que tanto o manejo do lençol mantido a 15 cm como o de elevação gradativa, embora com rendimento de grãos sem vantagem estatística sobre o manejo não-indutivo, foram efetivos, permitindo a planta completar seu ciclo, além de menor comprometimento na qualidade de grãos. A alternância de vantagens relativas biométricas entre os dois manejos não acarretou diferença estatística no rendimento de grãos, levando-se a inferir ser vantajoso o uso de cultivares de ciclo mais longo nesse tipo de condição.

Changes of beta-amyloid precursor protein splice patterns in brain cell aggregate cultures.

The splice pattern of beta-amyloid precursor protein (beta-APP) has been studied in a variety of neuronal and glial cells and in brain cell aggregate cultures by the polymerase chain reaction (PCR). The brain-typical pattern, in which beta-APP695 is the dominant form, has been found only in aggregate cultures but not in any of the other cell types including neuronal cell lines. Selective elimination of glial cells from aggregates resulted in increased quantities of beta-APP695, whereas removal of neurons led to a reduction of beta-APP695 and to an elevation of beta-APP751 and beta-APP770. This shift of splice pattern was not observed in cocultures of the neuronal cell line PC 12 with primary astrocytes combined in a variety of cellular ratios. Blood serum, which is an essential component of these cultures, tested on aggregates, did not reduce the amount of beta-APP695 or have any marked effects on splice patterns generally. From these results it is concluded that investigations on brain-typical splicing of beta-APP require primary neurons. Neuronal cell lines may be no suitable model systems. Splicing events favoring production of beta-APP695 may mark an important, very early step of amyloid formation in the brain.