Effect of ion reduction of sodium, calcium and potassium on spontaneous contraction of the esophagus of Pomacea lineata SPIX, 1827 (Mollusca-Gastropoda-Prosobranchia)

The invertebrate's musculature still presents many elusive points, especially in molluscs that generally present smooth and cracked fibers with peculiar characteristics. It was found that the molluscs reactions to the ion variation in the bathing are not very clear, mainly in view of the isolated reduction or equivalent of the ions. Suspended in bath, the isolated esophagus of the P. lineata exhibited spontaneous activity. This rhythmic activity was sensitive to the ion variation of the perfusion liquid, evidenced by alterations in the spontaneous contractions. The equivalent reduction of the ion reduced the spontaneous activity, evidenced by the amplitude reduction of the response, besides maintaning an organ contraction, primarily in the reductions below 50%. When the isolated reductions of the Na, Ca or K ion were performed, occurred interference in the spontaneous contractions of the organs, principally in amplitude of the response and maintenance of the contracture in reductions of 50 and 25% of the ion.

The respiratory responses of an amphibious snail Pomacea lineata (spix, 1827), to temperature and oxygen tension variations

1. 1. The respiratory responses of Pomacea lineata to short-term (or acute) exposure to temperature and oxygen tension variations were investigated in animals acclimated to 25°C. 2. 2. The respiratory rates increased with rising temperatures; this increase was sharper between 15 and 25°C than at any other temperature interval; a tendency to a plateau in the RT curve was recorded between 25 and 35°C. 3. 3. All animals survived well to 1 hr exposure to the extreme temperatures used (5 and 40°C). 4. 4. In two different experimental approaches, the animals showed ability to regulate the respiratory rate in declining oxygen tensions, at least down to 10% (70.8 mmHg) oxygen. 5. 5. After 1 hr exposure to hypoxic conditions, P. lineata exhibited the pattern of underpayment of the oxygen debt acquired. 6. 6. Six out of ten animals survived after 40 days in anoxia (100% nitrogen). © 1987.

Ascensão e queda do gabinete de 20 de novembro de 1827 (1827-1829)

Pós-graduação em História - FCHS

Ascensão e queda do gabinete de 20 de novembro de 1827 (1827-1829)

A difícil relação de Dom Pedro I com o Legislativo durante o seu reinado (1822 - 1831) é explicada frequentemente pelos historiadores como consequência do absolutismo do imperador e de seu desprezo a conceitos da então nascente ideologia liberal, como Constituição e divisão de poderes. No entanto, um fato político pouco destacado em estudos recentes sobre o período coloca essa imagem em cheque - a reforma ministerial de 1827, realizada pelo imperador, que resultou na nomeação de três integrantes da Câmara dos Deputados para postos-chave do poder Executivo. O fato foi visto como referência às políticas creditadas ao modelo em voga na Inglaterra, nação que para muitos havia alcançado um relacionamento harmonioso entre Executivo e Legislativo, por conta da alocação de deputados nas cadeiras dos ministérios. Com as nomeações, Dom Pedro I objetivava diminuir os conflitos políticos com a Câmara. Ao mesmo tempo, procurava fazer frente a deputados da oposição que atacavam as políticas de governo no Parlamento, o que sustenta a hipótese de que a habilidade retórica dos deputados nomeados teria sido uma causa importante para sua integração ao Executivo. Esta tese, defendida pelos primeiros historiadores, é retomada aqui, por meio da análise de dois conceitos - king-in-parliament e retórica -, desenvolvidos pelo político franco-suíço Benjamim Constant. O autor demonstra como foi criada a fórmula king-in-parliament na Inglaterra do século 18 e de que maneira a perceberam os políticos brasileiros durante o Primeiro Reinado. Por meio de fontes primárias, ele levanta os temas que fomentavam os debates na Câmara dos Deputados e mostra como se deu a participação dos parlamentares nomeados ao Ministério em defesa do governo imperial naquelas discussões. Para o autor, o estudo sobre o Gabinete de 20 de novembro de 1827 permite refutar a caracterização 'absolutista' que, em vários momentos, é impingida ao ..

First zoeal stage of ? Cataleptodius parvulus (Fabricius, 1793) and Xanthodius denticulatus (White, 1848) (Decapoda: Brachyura): larval evidences and systematic position

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The plants by Daniel Rolander (c. 1723-1793) in Diarium Surinamicum (1754-1765) and herbaria

The manuscripts of Diarium Surinamicum by Daniel Rolander practically remained ignored and unpublished for over 240 years, till the recent publication of its translation into English, which occurred in 2008. In this, the names of species described and/or cited by Rolander were faithfully retained, hence preserving the indication of them without authorship, for the vast majority. In the present work, all the names of plants that were treated by Rolander in his journal, about 664, including by tradition the fungi and algae, are contextualised in relation to the authorship, reference to the publication of the protologue, pagination of citations/descriptions in the manuscripts and in the published translation, indication of probable misidentifications with possible alternative names, vernacular names, and related literature. Additionally, we searched for the vouchers collected by Rolander, scattered in several herbaria, which have been linked to the probable names and descriptions in the diary. Given the considerable time till the publication of these names, and by the lack of indication of their nomenclatural types in the English version, the great majority of the new species described by Rolander, which would have priority if published in due time, became invalid names according to the ICN. Nevertheless, the list of Rolandrian species here presented, from his work that has finally taken a place in the history of natural sciences, shows that he was also a competent botanist, besides being a skilled entomologist, having recognised and detailedly described many of the Surinamese plants hitherto unknown to science.

Hsp90 transcriptionally and post-translationally regulates the expression of NDRG1 and maintains the stability of its modifying kinase GSK3beta

N-myc downstream-regulated gene 1 (NRDG1) is a stress-induced protein whose putative function is suppression of tumor metastasis. A recent proteonomic study showed NDRG1 interacts with the molecular chaperone heat shock protein 90 (Hsp90). From their reported association, we investigated if NDRG1 is dependent on Hsp90 for its stability and is therefore a yet unidentified Hsp90 client protein. Here, we demonstrate that endogenous NDRG1 and Hsp90 physically associate in hepatocellular cancer cell lines. However, geldanamycin (GA)-mediated inhibition of Hsp90 did not disrupt their interaction or result in NDRG1 protein destabilization. On the contrary, inhibition of Hsp90 led to a transcriptional increase of NDRG1 protein which was associated with cell growth arrest. We also observed that GA inhibited the phosphorylation of NDRG1 by targeting its regulating kinases, serum- and glucocorticoid-induced kinase 1 (SGK1) and glycogen synthase kinase 3 beta (GSK3beta). We demonstrate that in the presence of GA, GSK3beta protein and activity were decreased thus indicating that Hsp90 is necessary for GSK3beta stability. Taken together, our data demonstrate that NDRG1 is not a classic client protein but interacts with Hsp90 and is still dually regulated by Hsp90 at a transcriptional and post-translational level. Finally, we suggest for the first time GSK3beta as a new client protein of Hsp90.