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Midgut Epithelial Cells (midgut + epithelial_cell)
Selected AbstractsStorage and secretion of the peritrophic matrix protein Ag-Aper1 and trypsin in the midgut of Anopheles gambiaeINSECT MOLECULAR BIOLOGY, Issue 4 2004M. Devenport Abstract The gene Ag-Aper1 encodes a peritrophic matrix (PM) protein from the mosquito Anopheles gambiae. Ag-Aper1 gene expression and protein localization in the mosquito midgut were studied during the course of a blood meal. Ag-Aper1 mRNA abundance does not change appreciably during the course of blood ingestion and digestion. Prior to a blood meal, the protein is stored in secretory vesicles of midgut epithelial cells. Moreover, Ag-Aper1 colocalizes to the same secretory vesicles as trypsin, indicating that these proteins use a common secretory pathway. Blood feeding triggers the secretion of vesicle contents into the midgut lumen, after which Ag-Aper1 is incorporated into the PM. Newly synthesized Ag-Aper1 protein was again detected within the midgut epithelial cells at 60 h after blood ingestion. [source] Development of an orally infectious Sindbis virus transducing system that efficiently disseminates and expresses green fluorescent protein in Aedes aegyptiINSECT MOLECULAR BIOLOGY, Issue 2 2003D. J. Pierro Abstract We have constructed an orally infectious Sindbis virus, ME2/5,2J/GFP, that expresses green fluorescent protein (GFP) in the midgut of Aedes aegypti and in other tissues as the virus disseminates. This virus has two unique features that are improvements over the SIN-based expression systems currently used in mosquitoes. First, a subgenomic RNA promoter and GFP coding sequence is located 5,- to the second subgenomic promoter and structural genes of the virus. Second, the E2 glycoprotein gene of TE/5,2J/GFP is replaced with the E2 gene of MRE16 SIN virus. The first feature enhances virus genome stability during virus dissemination from the midgut to other tissues and the second allows efficient virus entry into the midgut epithelial cells and then spread of the virus throughout the mosquito. [source] Transgenic Drosophila reveals a functional in vivo receptor for the Bacillus thuringiensis toxin Cry1Ac1INSECT MOLECULAR BIOLOGY, Issue 6 2002Michael Gill Abstract The bacterium Bacillus thuringiensis synthesizes toxins (,-endotoxins) that are highly specific for insects. Once ingested, the activated form of the toxin binds to a specific receptor(s) located on the midgut epithelial cells, inserts into the membrane causing the formation of leakage pores and eventual death of the susceptible insect larvae. Manduca sexta larvae are highly susceptible to Cry1Ac1, a toxin that is believed to bind M. sexta Aminopeptidase N, a glycoprotein located on the apical membrane. However, the binding data obtained to date only support the interaction of Cry1Ac1 with APN in vitro. To explore the in vivo role of APN, we have utilized the GAL4 enhancer trap technique to drive the expression of M. sexta APN in both midgut and mesodermal tissues of Cry1Ac1 insensitive Drosophila larvae. Transgenic Drosophila fed the toxin were now killed, demonstrating that APN can function as a receptor for Cry1Ac1 in vivo. [source] Identification, physiological actions, and distribution of TPSGFLGMRamide: a novel tachykinin-related peptide from the midgut and stomatogastric nervous system of Cancer crabsJOURNAL OF NEUROCHEMISTRY, Issue 5 2007Elizabeth A. Stemmler Abstract In most invertebrates, multiple species-specific isoforms of tachykinin-related peptide (TRP) are common. In contrast, only a single conserved TRP isoform, APSGFLGMRamide, has been documented in decapod crustaceans, leading to the hypothesis that it is the sole TRP present in this arthropod order. Previous studies of crustacean TRPs have focused on neuronal tissue, but the recent demonstration of TRPs in midgut epithelial cells in Cancer species led us to question whether other TRPs are present in the gut, as is the case in insects. Using direct tissue matrix assisted laser desorption/ionization Fourier transform mass spectrometry, in combination with sustained off-resonance irradiation collision-induced dissociation, we found that at least one additional TRP is present in Cancer irroratus, Cancer borealis, Cancer magister, and Cancer productus. The novel TRP isoform, TPSGFLGMRamide, was present not only in the midgut, but also in the stomatogastric nervous system (STNS). In addition, we identified an unprocessed TRP precursor APSGFLGMRG, which was detected in midgut tissues only. TRP immunohistochemistry, in combination with preadsorption studies, suggests that APSGFLGMRamide and TPSGFLGMRamide are co-localized in the stomatogastric ganglion (STG), which is contained within the STNS. Exogenous application of TPSGFLGMRamide to the STG elicited a pyloric motor pattern that was identical to that elicited by APSGFLGMRamide, whereas APSGFLGMRG did not alter the pyloric motor pattern. [source] Acute oral toxicity of Yersinia pseudotuberculosis to fleas: implications for the evolution of vector-borne transmission of plagueCELLULAR MICROBIOLOGY, Issue 11 2007David L. Erickson Summary Yersinia pestis diverged from Yersinia pseudotuberculosis, 20 000 years ago, during which time it evolved to be transmitted by fleas. In comparing the ability of these closely related species to infect the rat flea Xenopsylla cheopis, we found that Y. pseudotuberculosis, unlike Y. pestis, is orally toxic to fleas. Fleas showed signs of acute toxicity, including diarrhoea, immediately after feeding on blood containing Y. pseudotuberculosis in response to protein toxin(s) produced by the bacteria. Adherence of Y. pseudotuberculosis to the midgut and large intracellular vacuoles in midgut epithelial cells were detected during the first 24 h after infection. The insect pathogen Photorhabdus luminescens and its TcdA1 and TcdB1-TccC1 insecticidal toxin complexes were similarly toxic to fleas, implicating the toxin complex (tc) genes also present in Yersinia species. However, the Y. pestis and Y. pseudotuberculosis TcaAB and TcaC-TccC proteins were non-toxic to fleas, and Y. pseudotuberculosis mutants deleted of tc genes retained acute toxicity. Our results indicate that loss of one or more insect gut toxins was a critical step in the recent evolution of flea-borne transmission in the genus Yersinia. Changes in the tc insecticidal genes do not appear to have been responsible, but may have had other effects on Yersinia,flea interactions. [source] Plasmodium,mosquito interactions: a tale of dangerous liaisonsCELLULAR MICROBIOLOGY, Issue 11 2005Carolina Barillas-Mury Summary To complete their life cycle, Plasmodium parasites must survive the environment in the insect host, cross multiple barriers including epithelial layers, and avoid destruction by the mosquito immune system. Completion of the Anopheles gambiae and Plasmodium falciparum genomes has opened the opportunity to apply high throughput methods to the analysis of gene function. The burst of information generated by these approaches and the use of molecular markers to investigate the cell biology of these interactions is broadening our understanding of this complex system. This review discusses our current understanding of the critical interactions that take place during the journey of Plasmodium through the mosquito host, with special emphasis on the responses of midgut epithelial cells to parasite invasion. [source] | ||||||||||