Screening phytochimique et identification spectroscopique des flavonoïdes d’Asteriscusgraveolenssubsp. odorus

Ce travail s’intéresse à l’étude phytochimique d’une espèce du Sud du Maroc appartenant à la famille des Asteraceae : Asteriscusgraveolenssubsp. odorus. Le screening phytochimique des feuilles et des fleurs de cette plante, effectuée pour la première fois, a révélé la présence des alcaloïdes, des flavonoïdes, des tanins catéchiques, des terpènes, des coumarines et des composés cyanogénétiques. Quant aux saponines et les quinones libres, ils sont présents chez les fleurs et absents chez les feuilles. La caractérisation des molécules par spectrophotométrie UV a révélé la présence de l’acide caféique, névadensine, lutéoline et artemétine dans les feuilles d’Asteriscus graveolens subsp. odorus.Mots-clés : analyse spectrophotométrique, screening phytochimique, asteriscus graveolens subsp. odorus

Is Mercury Orange a selective stain for thiols?

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42852/1/10735_2005_Article_BF01005240.pd

The main actors involved in parasitization of Heliothis virescens larva

At the moment of parasitization by another insect, the host Heliothis larva is able to defend itself by the activation of humoral and cellular defenses characterized by unusual reactions of hemocytes in response to external stimuli. Here, we have combined light and electron microscopy, staining reactions, and immunocytochemical characterization to analyze the activation and deactivation of one of the most important immune responses involved in invertebrates defense, i.e., melanin production and deposition. The insect host/parasitoid system is a good model to study these events. The activated granulocytes of the host insect are a major repository of amyloid fibrils forming a lattice in the cell. Subsequently, the exocytosed amyloid lattice constitutes the template for melanin deposition in the hemocel. Furthermore, cross-talk between immune and neuroendocrine systems mediated by hormones, cytokines, and neuromodulators with the activation of stress-sensoring circuits to produce and release molecules such as adrenocorticotropin hormone, alpha melanocyte-stimulating hormone, and neutral endopeptidase occurs. Thus, parasitization promotes massive morphological and physiological modifications in the host insect hemocytes and mimics general stress conditions in which phenomena such as amyloid fibril formation, melanin polymerization, pro-inflammatory cytokine production, and activation of the adrenocorticotropin hormone system occur. These events observed in invertebrates are also reported in the literature for vertebrates, suggesting that this network of mechanisms and responses is maintained throughout evolution

Use of beneficial bacteria and their secondary metabolites to control grapevine pathogen diseases

Grapevine is one of the most important economic crops yielding berries, wine products as well as derivates. However, due to the large array of pathogens inducing diseases on this plant, considerable amounts of pesticides—with possible negative impact on the environment and health—have been used and are currently used in viticulture. To avoid negative impacts of such products and to ensure product quality, a substantial fraction of pesticides needs to be replaced in the near future. One solution can be related to the use of beneficial bacteria inhabiting the rhizo- and/or the endosphere of plants. These biocontrol bacteria and their secondary metabolites can reduce directly or indirectly pathogen diseases by affecting pathogen performance by antibiosis, competition for niches and nutrients, interference with pathogen signaling or by stimulation of host plant defenses. Due to the large demand for biocontrol of grapevine diseases, such biopesticides, their modes of actions and putative consequences of their uses need to be described. Moreover, the current knowledge on new strains from the rhizo- and endosphere and their metabolites that can be used on grapevine plants to counteract pathogen attack needs to be discussed. This is in particular with regard to the control of root rot, grey mould, trunk diseases, powdery and downy mildews, pierce’s disease, grapevine yellows as well as crown gall. Future prospects on specific beneficial microbes and their secondary metabolites that can be used as elicitors of plant defenses and/or as biocontrol agents with potential use in a more sustainable viticulture will be further discussed

Selective IgA Deficiency

Immunoglobulin A (IgA) deficiency is the most common primary immunodeficiency defined as decreased serum level of IgA in the presence of normal levels of other immunoglobulin isotypes. Most individuals with IgA deficiency are asymptomatic and identified coincidentally. However, some patients may present with recurrent infections of the respiratory and gastrointestinal tracts, allergic disorders, and autoimmune manifestations. Although IgA is the most abundant antibody isotype produced in the body, its functions are not clearly understood. Subclass IgA1 in monomeric form is mainly found in the blood circulation, whereas subclass IgA2 in dimeric form is the dominant immunoglobulin in mucosal secretions. Secretory IgA appears to have prime importance in immune exclusion of pathogenic microorganisms and maintenance of intestinal homeostasis. Despite this critical role, there may be some compensatory mechanisms that would prevent disease manifestations in some IgA-deficient individuals. In IgA deficiency, a maturation defect in B cells to produce IgA is commonly observed. Alterations in transmembrane activator and calcium modulator and cyclophilin ligand interactor gene appear to act as disease-modifying mutations in both IgA deficiency and common variable immunodeficiency, two diseases which probably lie in the same spectrum. Certain major histocompatibility complex haplotypes have been associated with susceptibility to IgA deficiency. The genetic basis of IgA deficiency remains to be clarified. Better understanding of the production and function of IgA is essential in elucidating the disease mechanism in IgA deficiency

Positive Selection Shaped the Convergent Evolution of Independently Expanded Kallikrein Subfamilies Expressed in Mouse and Rat Saliva Proteomes

We performed proteomics studies of salivas from the genome mouse (C57BL/6 strain) and the genome rat (BN/SsNHsd/Mcwi strain). Our goal was to identify salivary proteins with one or more of three characteristics that may indicate that they have been involved in adaptation: 1) rapid expansion of their gene families; 2) footprints of positive selection; and/or 3) sex-limited expression. The results of our proteomics studies allow direct comparison of the proteins expressed and their levels between the sexes of the two rodent species. Twelve members of the Mus musculus species-specific kallikrein subfamily Klk1b showed sex-limited expression in the mouse saliva proteomes. By contrast, we did not find any of the Rattus norvegicus species-specific kallikrein subfamily Klk1c proteins in male or female genome rat, nor transcripts in their submandibular glands. On the other hand, we detected expression of this family as transcripts in the submandibular glands of both sexes of Sprague-Dawley rats. Using the CODEML program in the PAML package, we demonstrate that the two rodent kallikrein subfamilies have apparently evolved rapidly under the influence of positive selection that continually remodeled the amino acid sites on the same face in the members of the subfamilies. Thus, although their kallikrein subfamily expansions were independent, this evolutionary pattern has occurred in parallel in the two rodent species, suggesting a form of convergent evolution at the molecular level. On the basis of this new data, we suggest that the previous speculative function of the species-specific rodent kallikreins as important solely in wound healing in males be investigated further. In addition to or instead of that function, we propose that their sex-limited expression, coupled with their rapid evolution may be clues to an as-yet-undetermined interaction between the sexes

Imaging and imagination: understanding the endo-lysosomal system

Lysosomes are specialized compartments for the degradation of endocytosed and intracellular material and essential regulators of cellular homeostasis. The importance of lysosomes is illustrated by the rapidly growing number of human disorders related to a defect in lysosomal functioning. Here, we review current insights in the mechanisms of lysosome biogenesis and protein sorting within the endo-lysosomal system. We present increasing evidence for the existence of parallel pathways for the delivery of newly synthesized lysosomal proteins directly from the trans-Golgi network (TGN) to the endo-lysosomal system. These pathways are either dependent or independent of mannose 6-phosphate receptors and likely involve multiple exits for lysosomal proteins from the TGN. In addition, we discuss the different endosomal intermediates and subdomains that are involved in sorting of endocytosed cargo. Throughout our review, we highlight some examples in the literature showing how imaging, especially electron microscopy, has made major contributions to our understanding of the endo-lysosomal system today

Imaging of subsurface lineaments in the southwestern part of the Thrace Basin from gravity data

Linear anomalies, as an indicator of the structural features of some geological bodies, are very important for the interpretation of gravity and magnetic data. In this study, an image processing technique known as the Hough transform (HT) algorithm is described for determining invisible boundaries and extensions in gravity anomaly maps. The Hough function implements the Hough transform used to extract straight lines or circles within two-dimensional potential field images. It is defined as image and Hough space. In the Hough domain, this function transforms each nonzero point in the parameter domain to a sinusoid. In the image space, each point in the Hough space is transformed to a straight line or circle. Lineaments are depicted from these straight lines which are transformed in the image domain. An application of the Hough transform to the Bouguer anomaly map of the southwestern part of the Thrace Basin, NW Turkey, shows the effectiveness of the proposed approach. Based on geological data and gravity data, the structural features in the southwestern part of the Thrace Basin are investigated by applying the proposed approach and the Blakely and Simpson method. Lineaments identified by these approaches are generally in good accordance with previously-mapped surface faults