NELF Potentiates Gene Transcription in the Drosophila Embryo

A hallmark of genes that are subject to developmental regulation of transcriptional elongation is association of the negative elongation factor NELF with the paused RNA polymerase complex. Here we use a combination of biochemical and genetic experiments to investigate the in vivo function of NELF in the Drosophila embryo. NELF associates with different gene promoter regions in correlation with the association of RNA polymerase II (Pol II) and the initial activation of gene expression during the early stages of embryogenesis. Genetic experiments reveal that maternally provided NELF is required for the activation, rather than the repression of reporter genes that emulate the expression of key developmental control genes. Furthermore, the relative requirement for NELF is dictated by attributes of the flanking cis-regulatory information. We propose that NELF-associated paused Pol II complexes provide a platform for high fidelity integration of the combinatorial spatial and temporal information that is central to the regulation of gene expression during animal development

Characterisation of the dry salted process for the production of the msayer, a traditional lemon aromatising condiment

Msayer is a dry salted lemon used as an aromatising condiment in many North-African food recipes. This preparation is obtained by adding coarse salt (10 g/100 g fresh lemons) to fresh cut lemons in containers kept under dark conditions away from air for around a month and a half A survey of 52 days showed low initial uptake of citric acid and sugars from the formed liquid phase. Nevertheless, there were still sugars detected even at the end of the survey attesting for the low microbial activity as also shown by carbon dioxide production and microbial viable counts. Indeed, the microbial counts showed a steady decrease reaching 2 log units at the 52nd day of curing. Moulds were detected only at the beginning but at low numbers. No viable counts of lactic acid bacteria were observed on MRS medium despite detection of lactic acid (8 g/l). In contrast, yeasts seem to dominate in the msayer preparation. They count for almost all the microbial population especially after the first week. Six of these acid and halotolerant yeast isolates were identified, by sequence analysis of the amplified 5.8S rRNA and the two internal transcribed spacer regions, as Candida parapsislosis (2 isolates) and unclassified Saccharomycetales (4 isolates). Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved

Contribution À La Caractérisation Microbiologique Et Enzymatique D'un Site Extrême :Les Tanneries Traditionnelles De Fès

<p>ABSTRACT: Microorganisms in general are of abounding sources of unique enzymes that can be particularly<br>used in biotechnology. To face up the growing request of the industrialists notably in the field of biocatalysises,<br>numerous efforts are provided for the research of enzymes of interest. This concerns principally enzymes<br>coming from extremophiles microorganisms. These enzymes will be undoubtedly of a big interest to intervene in<br>close future in industrial techniques. It is as part of a possible promotion of microbic means by use of their<br>enzymes that we accomplished a first job which is interested in an extreme middle ' the traditional tanneries of<br>Fez. In a first shutter, we performed a physicochemical characterization of different stages of tanning; then we<br>undertook the isolation of microorganisms by a bet in culture on appropriate medium and at the end, we could<br>revealed certain of enzymatic potentialities (cellulase, pectinase, amylase, tannase and lipase) that the cleaned<br>microbic isolats culminates.</p> <p> </p

Conserved Domains of the Nullo Protein Required for Cell-Surface Localization and Formation of Adherens Junctions

During cellularization, the Drosophila melanogaster embryo undergoes a transition from syncytial to cellular blastoderm with the de novo generation of a polarized epithelial sheet in the cortex of the embryo. This process couples cytokinesis with the establishment of apical, basal, and lateral membrane domains that are separated by two spatially distinct adherens-type junctions. In nullo mutant embryos, basal junctions fail to form at the onset of cellularization, leading to the failure of cleavage furrow invagination and the generation of multinucleate cells. Nullo is a novel protein that appears to stabilize the initial accumulation of cadherins and catenins as they form a mature basal junction. In this article we characterize a nullo homologue from D. virilis and identify conserved domains of Nullo that are required for basal junction formation. We also demonstrate that Nullo is a myristoylprotein and that the myristate group acts in conjunction with a cluster of basic amino acids to target Nullo to the plasma membrane. The membrane association of Nullo is required in vivo for its role in basal junction formation and for its ability to block apical junction formation when ectopically expressed during late cellularization