Unveiling the components of the signaling pathway between endosomes and the phagocytic uptake machinery in Dictyostelium discoideum

The soil amoebae Dictyostelium discoideum take up particles from their environment in order to obtain nutrition. The particle transits through the cell within a phagosome that fuses with organelles of different molecular compositions, undergoing a gradual degradation by different sets of hydrolytic enzymes. Griffiths’ concept of “phagosome individuality” predicts signaling from phagosomes into the cytoplasm, which might regulate many aspects of cell physiology. The finding that Dictyostelium cells depleted of the lysozyme AlyA or over-expressing the esterase Gp70 exhibit increased uptake of food particles, led to the postulation of a signaling cascade between endocytic compartments and the cytoskeletal uptake machinery at the plasma membrane. Assuming that Gp70 acts downstream of AlyA, gene-expression profiling of both mutants revealed different and overlapping sets of misregulated genes that might participate in this signaling cascade. Based on these results, we analyzed the effects of the artificial misregulation of six candidate genes by over-expression or negative genetic interference, in order to reconstruct at least part of the signaling pathway. SSB420 and SSL793 were chosen as candidates for the first signaling step, as they were up-regulated in AlyA-null cells and remained unaltered in the Gp70 over-expressing cells. The over-expression of SSB420 enhanced phagocytosis and raised the expression levels of Gp70, supporting its involvement in the signaling pathway between AlyA and Gp70 as a positive regulator of phagocytosis. However, this was not the case of cells over-expressing SSL793, as this mutation had no effects on phagocytosis. For the signaling downstream of Gp70, we studied four commonly misregulated genes in AlyA-depleted and Gp70 over-expressing cells. The expression levels of SLB350, SSB389 and TipD were lower in both mutants and therefore these were assumed as possible candidates for the negative regulation of phagocytosis. Cells depleted of SLB350 exhibited an increased phagocytic activity and no effect on Gp70 expression, proving its participation in the signaling pathway downstream of Gp70. Unlike SLB350, the disruption of the genes coding for SSB389 and TipD had no effects on particle uptake, excluding them from the pathway. The fourth candidate was Yipf1, the only gene that was commonly up-regulated in both mutants. Yet, the artificial over-expression of this protein had no effects on phagocytosis, so this candidate is also not included in the signaling pathway. Furthermore, localizing the products of the candidate genes within the cell helped unveiling several cellular organelles that receive signals from the phagosome and transduce them towards the uptake machinery.

The circulation of romances from England in late-medieval Ireland

The fifteenth century saw a striking upturn in the number of texts from foreign vernaculars that were translated into Irish. Indeed, one might go so far as to speak in terms of a ‘translation trend’ in Ireland during the mid to late fifteenth century. A notable feature of this trend is that a particularly high number of these Irish translations are of romances; contextual and textual evidence suggests that the original exemplars for many of these translated texts appear to have come from England, though not all of them were necessarily in English. Irish translations of eight romances have survived to the present day: Guy of Warwick; Bevis of Hampton; La Queste de Saint Graal; Fierabras; Caxton’s Recuyell of the Histories of Troie; William of Palerne; the Seven Sages of Rome; and Octavian. This paper addresses two aspects of these texts of particular relevance to romance scholars who do not work within the sphere of Celtic studies. Firstly, it argues that certain aspects of the dissemination and reception of romance in Ireland are quite distinctive. Manuscript and textual evidence suggests that the religious orders, particularly the Franciscans, seem to have played a role in the importation and translation of these narratives. Secondly, examination of the Irish versions of romance tends to bear out an observation made by Flower many years ago, but not pursued by subsequent scholars: ‘texts of an unusual kind were current in Ireland, and it may be that interesting discoveries are to be made here’. Certain narrative features of several of these Irish translations diverge from all the surviving versions of the relevant romance in other languages and may witness to a variant exemplar that has since been lost from its own linguistic corpus.

Walter Chatton y Adam of Wodeham : dos perspectivas medievales funcionalistas sobre la naturaleza de algunos estados mentales

En este artículo tenemos como objetivo mostrar que, por una parte, en oposición a la teoría de William of Ockham, las teorías de Walter Chatton y Adam of Wodeham convienen con la doctrina contemporánea según la cual los estados mentales son estados funcionales de un cierto tipo. Por otra parte, en este artículo queremos revelar que aquellas teorías medievales que podemos llamar funcionalistas fundamentan una perspectiva económica medieval respecto a la composición de un ser humano.

History of the St. Mary's Falls ship canal, showing the early efforts which were made to secure its construction, with a record of the business of the canal from its opening until the present time ...

Mode of access: Internet.

The social history and antiquities of Barton-upon-Humber.

Mode of access: Internet.

The return of Louis XVIII;

Mode of access: Internet.

The Church historians of England.

Title varies.

Ockham on Aristotle's Physics : a translation of Ockham's Brevis summa libri physicorum /

Includes bibliographical references (p. [141]-142).

Wintering in the Riviera, with notes of travel in Italy and France, and practical hints to travellers,

Mode of access: Internet.

Griffith John, founder of the Hankow Mission, central China.

Mode of access: Internet.

The Poets and poetry of Scotland : from the earliest to the present time, comprising characteristic selections from the works of the more noteworthy Scottish poets /

I. From Thomas the Rhymer to Richard Gall, [1219-1776] -- II. From Thomas Campbell to Marquis of Lorne, [1777-1876].

Life in the Niger : or, the journal of an African trade /

Mode of access: Internet.

The history of Winterton and the adjoining villages ...

Mode of access: Internet.

[Witchcraft detected and prevented, or the School of Black Art newly opened] ... /

Mode of access: Internet.

Considerations suggested by the establishment of a second college in Connecticut.

Supposed to have been written by R. S. Baldwin, according to Dexter, Biog. Sketches of grads. of Yale, v.6, p. 371, and Steiner, Hist. of educ. in Conn., p. 242. Attributed to C. A. Goodrich by Cushing, Anonyms, p. 145. cf. Trinity College, Bibliog. of official pubs., 1824-1905, p. 31.