Search results for "precursor"
showing 10 items of 490 documents
Different mechanisms of resistance to Bacillus thuringiensis toxins in the indianmeal moth.
2001
ABSTRACT Susceptibility to protoxin and toxin forms of Cry1Ab and the binding of 125 I-labeled Cry1Ab and Cry1Ac has been examined in three Plodia interpunctella colonies, one susceptible (688 s ) and two resistant (198 r and Dpl r ) to Bacillus thuringiensis . Toxicological studies showed that the 198 r colony was 11-fold more resistant to Cry1Ab protoxin than to Cry1Ab activated toxin, whereas the Dpl r colony was 4-fold more resistant to protoxin versus toxin. Binding results with 125 I-labeled toxins indicated the occurrence of two different binding sites for Cry1Ab in the susceptible insects, one of them shared with Cry1Ac. Cry1Ab binding was found to be altered in insects from both re…
Lack of APP and APLP2 in GABAergic Forebrain Neurons Impairs Synaptic Plasticity and Cognition.
2020
AbstractAmyloid-β precursor protein (APP) is central to the pathogenesis of Alzheimer’s disease, yet its physiological functions remain incompletely understood. Previous studies had indicated important synaptic functions of APP and the closely related homologue APLP2 in excitatory forebrain neurons for spine density, synaptic plasticity, and behavior. Here, we show that APP is also widely expressed in several interneuron subtypes, both in hippocampus and cortex. To address the functional role of APP in inhibitory neurons, we generated mice with a conditional APP/APLP2 double knockout (cDKO) in GABAergic forebrain neurons using DlxCre mice. These DlxCre cDKO mice exhibit cognitive deficits i…
Melittin Modulates Keratinocyte Function through P2 Receptor-dependent ADAM Activation
2012
Melittin, the major component of the bee venom, is an amphipathic, cationic peptide with a wide spectrum of biological properties that is being considered as an anti-inflammatory and anti-cancer agent. It modulates multiple cellular functions but the underlying mechanisms are not clearly understood. Here, we report that melittin activates disintegrin-like metalloproteases (ADAMs) and that downstream events likely contribute to the biological effects evoked by the peptide. Melittin stimulated the proteolysis of ADAM10 and ADAM17 substrates in human neutrophil granulocytes, endothelial cells and murine fibroblasts. In human HaCaT keratinocytes, melittin induced shedding of the adhesion molecu…
Unsaturated Fatty Acids Drive Disintegrin and Metalloproteinase (ADAM)-dependent Cell Adhesion, Proliferation, and Migration by Modulating Membrane F…
2011
The disintegrin-metalloproteinases ADAM10 and ADAM17 mediate the release of several cell signaling molecules and cell adhesion molecules such as vascular endothelial cadherin or L-selectin affecting endothelial permeability and leukocyte transmigration. Dysregulation of ADAM activity may contribute to the pathogenesis of vascular diseases, but the mechanisms underlying the control of ADAM functions are still incompletely understood. Atherosclerosis is characterized by lipid plaque formation and local accumulation of unsaturated free fatty acids (FFA). Here, we show that unsaturated FFA increase ADAM-mediated substrate cleavage. We demonstrate that these alterations are not due to genuine ch…
Proteomic Analyses Reveal an Acidic Prime Side Specificity for the Astacin Metalloprotease Family Reflected by Physiological Substrates
2011
Astacins are secreted and membrane-bound metalloproteases with clear associations to many important pathological and physiological processes. Yet with only a few substrates described their biological roles are enigmatic. Moreover, the lack of knowledge of astacin cleavage site specificities hampers assay and drug development. Using PICS (proteomic identification of protease cleavage site specificity) and TAILS (terminal amine isotopic labeling of substrates) degradomics approaches >3000 cleavage sites were proteomically identified for five different astacins. Such broad coverage enables family-wide determination of specificities N- and C-terminal to the scissile peptide bond. Remarkably, me…
Analysis of Complete Neuroblast Cell Lineages in the Drosophila Embryonic Brain via DiI Labeling
2013
Proper functioning of the brain relies on an enormous diversity of neural cells generated by neural stem cell-like neuroblasts (NBs). Each of the about 100 NBs in each side of brain generates a nearly invariant and unique cell lineage, consisting of specific neural cell types that develop in defined time periods. In this chapter we describe a method that labels entire NB lineages in the embryonic brain. Clonal DiI labeling allows us to follow the development of an NB lineage starting from the neuroectodermal precursor cell up to the fully developed cell clone in the first larval instar brain. We also show how to ablate individual cells within an NB clone, which reveals information about the…
Potassium-inhibited processing of IL-1 beta in human monocytes.
1995
Agents that deplete cells of K+ without grossly disrupting the plasma membrane were found to stimulate the cleavage of pro-interleukin (IL)-1 beta to mature IL-1 beta. Agents examined in this study included staphylococcal alpha-toxin and gramicidin, both of which selectively permeabilize plasma membranes for monovalent ions, the ionophores nigericin and valinomycin, and the Na+/K+ ATPase inhibitor ouabain. K+ depletion by brief hypotonic shock also triggered processing of pro-IL-1 beta. The central role of K+ depletion for inducing IL-1 beta maturation was demonstrated in cells permeabilized with alpha-toxin: processing of pro-IL-1 beta was totally blocked when cells were suspended in mediu…
The prophenoloxidase system is activated during the tunic inflammatory reaction of Ciona intestinalis
2008
Phenoloxidase (PO) activity was examined in the tunic tissue of Ciona intestinalis following lipopolysaccharide (LPS) intratunic injection. Tunic homogenate supernatant (THS), assayed with the Dopa-MBTH reaction, displayed Ca(2+)-independent PO activity that was raised by LPS and further enhanced by proteases. Specific inhibitors (tropolone, phenylthiourea, diethylthiocarbamate) supported the specificity of the reaction. Assay with soybean trypsin inhibitor showed that, in the tunic, PO activation with trypsin was not significantly inhibited suggesting that proteases diverse from serine proteases were involved. In vivo experiments were carried out by injecting isosmotic medium or LPS, and T…
Clinical Utility of Midregional Proadrenomedullin in Patients with COVID-19
2021
Abstract Objective The aim of the study was to assess the role of midregional proadrenomedullin (MR-proADM) in patients with COVID-19. Methods We included 110 patients hospitalized for COVID-19. Biochemical biomarkers, including MR-proADM, were measured at admission. The association of plasma MR-proADM levels with COVID-19 severity, defined as a requirement for mechanical ventilation or in-hospital mortality, was evaluated. Results Patients showed increased levels of MR-proADM. In addition, MR-proADM was higher in patients who died during hospitalization than in patients who survived (median, 2.59 nmol/L; interquartile range, 2.3–2.95 vs median, 0.82 nmol/L; interquartile range, 0.57–1.03; …
Acid Dnase Activities In Peripheral, Mononuclear Blood Cells: A Possible Parameter To Detect Proliferating Cell Populations
1992
After electrophoresis in DNA -containing polyacrylamide gels, two acid DNase activities can be detected in peripheral, mononuclear cells of the human blood. One of these acid DNase activities correlates with cell proliferation; its isoelectrical point is at pI 7.4. By means of this DNase activity, a quantity of less than 1% leukemic cells can be detected. The increased acid DNase activity can indicate the proliferation of malignant cell populations and possibly the proliferation of cell populations during immunological reactions