Dynamin-dependent endocytosis is necessary for convergent-extension movements in Xenopus animal cap explants

Cadherin cell-cell adhesion molecules are important determinants of morphogenesis and tissue patterning. C-cadherin plays a key role in the cell-upon-cell movements seen during Xenopus gastrulation. In particular, regulated changes in C-cadherin adhesion critically influence convergence-extension movements, thereby determining organization of the body plan. It is also predicted that remodelling of cadherin adhesive contacts is important for such cell-on-cell movements to occur. The recent demonstration that Epithelial (E-) cadherin is capable of undergoing endocytic trafficking to and from the cell surface presents a potential mechanism for rapid remodelling of such adhesive contacts. To test the potential role for C-cadherin endocytosis during convergence-extension, we expressed in early Xenopus embryos a dominantly-inhibitory mutant of the GTPase, dynamin, a key regulator of clathrin-mediated endocytosis. We report that this dynamin mutant significantly blocked the elongation of animal cap explants in response to activin, accompanied by inhibition of C-cadherin endocytosis. We propose that dynamin-dependent endocytosis of C-cadherin plays an important role in remodelling adhesive contacts during convergence-extension movements in the early Xenopus embryo.

Amino acids 1-20 of the hepatitis C virus (HCV) core protein specifically inhibit HCV IRES- dependent translation in Hep G2 cells, and inhibit both HCV IRES- and cap-dependent translation in HuH7 and CV-1 cells.

A self-modulating mechanism by the hepatitis C virus (HCV) core protein has been suggested to influence the level of HCV replication, but current data on this subject are contradictory. We examined the effect of wild-type and mutated core protein on HCV IRES- and cap-dependent translation. The wild-type core protein was shown to inhibit both IRES- and cap-dependent translation in an in vitro system. This effect was duplicated in a dose-dependent manner with a synthetic peptide representing amino acids 1-20 of the HCV core protein. This peptide was able to bind to the HCV IRES as shown by a mobility shift assay. In contrast, a peptide derived from the hepatitis B virus (HBV) core protein that contained a similar proportion of basic residues was unable to inhibit translation or bind the HCV IRES. A recombinant vaccinia-HCV core virus was used to examine the effect of the HCV core protein on HCV IRES-dependent translation in cells and this was compared with the effects of an HBV core-recombinant vaccinia virus. In CV-1 and HuH7 cells, the HCV core protein inhibited translation directed by the IRES elements of HCV, encephalomyocarditis virus and classical swine fever virus as well as cap-dependent translation, whereas in HepG2 cells, only HCV IRES-dependent translation was affected. Thus, the ability of the HCV core protein to selectively inhibit HCV IRES-dependent translation is cell-specific. N-terminal truncated (aa 1-20) HCV core protein that was expressed from a novel recombinant vaccinia virus in cells abrogated the inhibitory phenotype of the core protein in vivo, consistent with the above in vitro data.

Remoção do herbicida 2,4 diclorofenoxiacético (2,4-D) no tratamento convencional de água e associado à adsorção em carvão ativado em pó (CAP) em escala piloto

O aumento do uso de agrotóxicos no Brasil tem causado muitas preocupações, tanto em relação à questão ambiental quanto a saúde pública. Muitos desses compostos não são eficientemente removidos das águas por tratamento convencional, sendo necessárias alternativas que os removam das águas de abastecimento. Dentre as tecnologias existentes, a adsorção em CAP é considerada uma das mais efetivas e confiáveis, cujas vantagens incluem alta eficiência de remoção e facilidade de operação. O objetivo desta pesquisa é avaliar a remoção, em escala piloto, do agrotóxico 2,4-D e o seu principal metabólito 2,4-DCP em amostras de águas tratadas por adsorção em CAP associado ao tratamento convencional. Os testes foram realizados em instalação piloto na áreada ETA Carapina/CESAN. A água bruta foi a proveniente do rio Santa Maria da Vitória contaminadaatravés da adição de agrotóxico em sua fórmula comercial. Foram realizados quatro ensaios, dois sem adição de CAP e dois com adição de CAP junto à unidade de mistura rápida. Os agrotóxicos foram detectados e quantificados através da cromatografia líquida de alta eficiência, em metodologia validada. As amostras coletadas foram caracterizadas de acordo com os parâmetros: temperatura, turbidez, condutividade elétrica, absorbância em 254 nm, cor real, cor aparente, alcalinidade, carbono orgânico total, além e concentração dos agrotóxicos 2,4-D e ácido 2,4,5-T e do metabólito 2,4-DCP. Os diferentes ensaios foram avaliados em termos da taxa de remoção destes parâmetros. Como resultado no TCVcom adição de CAP o composto de interesse foi removido abaixo de 30 μg. L-1,Valor Máximo Permitido, estabelecido pela Portaria do MS n° 2.914/2011 para dosagem de 100μg.L-1e mostrou-se eficiente, também, na remoção de matéria orgânica. Em nenhum dos testes foi detectado o composto 2,4-DCP e 2,4,5-T.

Âges K-Ar de glauconites des environs de Luz de Tavira, Algarve

Glauconite K-Ar ages (6.88±0.4; 7.03±0.4 MY) confirm earlier reports to Upper Tortonian of silt beds near Morgadinho, Luz de Tavira and Tavira. Taking stratigraphical position and age into account it is possible now to correlate these beds with similar ones at Quelfes and Cacela (Formação de Cacela, lower member, ascribed to the upper part of N16 or to NI7 Blow's zone, Globorotalia humerosa - G. dutertrei; Tortonian to Messinian, according to the ostracod fauna). Limit between the above quoted zones is thus placed at about 7 MY. New K-Ar ages greatly improve the knowledge about Upper Miocene in eastern Algarve, and on regional tectonic evolution. This is particulary so in what concerns an intra-Tortonian phase.

Description de restes squelettiques de Latidae: Lates (?) sp. (Poissons téléostéens, Percoidei) du Miocène inférieur et moyen du bassin du Bas Tage (environs de Lisbonne, Portugal)

Several Lower and Middle Miocene localities in the Lower Tagus basin near Lisbon yielded Latidae fragmentary remnants. No really decisive character has been recognized that would allow us to state these remnants could surely be ascribed to the genus Lates Cuv. & Val., although we regard this as nearly certain. There are some differences between the Miocene latidae under study and the type species Lates niloticus L. this suggests us to report the concerned remnants to a Lates (?) sp. that could belong to a new, hitherto undescribed species. The occurrence of Lates in fluviatile or lagoonal beds in the Lower Tagus basin Miocene series is not at all surprising under a paleoeciological view point. Even less if account is taken of the presence in the same levels of Siluriforms remnants belonging to Bagridae and Ariidae, two families that are well represented in Africa. Bagrid spines have been found at Quinta das Pedreiras in association with Lates (?) sp. remnants. The Lates (?) sp. discovery in the Lower and Middle Miocene from the Lower Tagus basin results in extending to the West this genus' biogeographic distribution. It is indeed the first discovery of this genus on Europe's Atlantic coasts. No matter which was the geographic origin of these fishes, they had to migrate several hundreds of kilometers through marine waters before entering the Tagus' estuary. The association of Lates (?) sp. remnants with Siluriform ones that have an extant, broad repartition in Africa south of the Sahara points out to an African origin. These thermophyll fishes imigration along the Atlantic coasts from lberian Peninsula probably has been possible owing to a warm climatic event that allowed them to migrate ca. 5 degrees (in latitude) northwards in Burdigalian times.

Une succession de référence pour le Toarcien Moyen et Supérieur: les "Margas calcárias de São Gião" dans les environs de Cantanhede (sous-bassin nord lusitanien, Portugal)*

The geological sections studied at the São Gião sector (Cantanhede region) have allowed the establishment of a clear succession of ammonite associations during the Middle and Upper Toarcian (“Margas calcárias de São Gião” and “Calcários margosos de Póvoa da Lomba” Formations). The fossil collections were gathered over the last 40 years and, in spite of the apparent facies monotony, come from a thick and fossiliferous marly-limestone unit. The ammonite succession allows the establishment and/or verification of a certain number of biostratigraphical elements, of which are worthy of mention: – the tethyan character of the fauna from the Gradata to the Meneghinii Zones; this differentiation starts with the occurrence of Collina, Crassiceras and Furloceras of the Gradata Zone; – the succession of Osperleioceras, with the connection between the “caussenardes”(O. reynesi, O. authelini) forms and those from Algeria (O. nadorense, O. matteii), which is placed at the beginning of the Aalensis Zone; – the succession of Hammatoceratinae: H. roubanense (Gradata Z.), H. bonarellii (Bonarellii Z.), H. speciosum (Speciosum Sub-zone), followed by Crestaites meneghinii (Reynesi Sub-zone and Meneghinii Z.); Pseudaptetoceras appear next (Aalensis Zone). The dynamic evolution of the sector is characterized by the persistence of marly sedimentation during the Meneghinii Zone, in probable relation to the paleostructural play of the Arunca-Montemor meridian axis.

"Eu sou o ontem, o hoje e o amanhã" (livro dos mortos do Antigo Egipto, cap. 64)

Quando estudamos a civilização egípcia há dois fenômenos que, inevitavelmente, nos surpreendem. Um prende-se com a durabilidade desta civiUzação. O ouü-o refere-se à manutenção quase absoluta das diferentes expressões do seu rosto. Aparentemente, uma e outi-a realidade são distintas, mas quando nos debmçamos sobre a história do Egipto faraônico compreendemos que ela durou, exactamente por que se manteve, ao longo de ti-ês milênios, fechada sobre si própria, num discurso e numa posUira que remontava às origens do mundo e da sua história.

Caracterização e análise da metodologia de desenho e estimação em inquérito por amostragem em Moçambique: uma aplicação prática ao Censo Agro-Pecuário 2009/10 (CAP II Moçambique) para pequenas explorações agrícolas

Dissertação apresentada como requisito parcial para obtenção do grau de Mestre em Estatística e Gestão de Informação

Mission scientifique du cap Horn, 1882-1883.

t.6:ptie.2:pt.1-5 (1891)

Florula bostoniensis. A collection of plants of Boston and its environs, with their generic and specific characters, synonyms, descriptions, places of growth, and time of flowering, and occasional remarks.

1st ed.

Mission scientifique du cap Horn, 1882-1883.

t.6:ptie.2:pt.4 (1888)