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Funk A Mhamdi M Hohenberg H Heeren J Reimer R Lambert C Prange R Sirma H 《Journal of virology》2008,82(21):10532-10542
The identity and functionality of biological membranes are determined by cooperative interaction between their lipid and protein constituents. Cholesterol is an important structural lipid that modulates fluidity of biological membranes favoring the formation of detergent-resistant microdomains. In the present study, we evaluated the functional role of cholesterol and lipid rafts for entry of hepatitis B viruses into hepatocytes. We show that the duck hepatitis B virus (DHBV) attaches predominantly to detergent-soluble domains on the plasma membrane. Cholesterol depletion from host membranes and thus disruption of rafts does not affect DHBV infection. In contrast, depletion of cholesterol from the envelope of both DHBV and human HBV strongly reduces virus infectivity. Cholesterol depletion increases the density of viral particles and leads to changes in the ultrastructural appearance of the virus envelope. However, the dual topology of the viral envelope protein L is not significantly impaired. Infectivity and density of viral particles are partially restored upon cholesterol replenishment. Binding and entry of cholesterol-deficient DHBV into hepatocytes are not significantly impaired, in contrast to their release from endosomes. We therefore conclude that viral but not host cholesterol is required for endosomal escape of DHBV. 相似文献
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Mechri Sondes Bouacem Khelifa Zaraî Jaouadi Nadia Rekik Hatem Ben Elhoul Mouna Omrane Benmrad Maroua Hacene Hocine Bejar Samir Bouanane-Darenfed Amel Jaouadi Bassem 《Extremophiles : life under extreme conditions》2019,23(6):687-706
Extremophiles - A thermostable extracellular alkaline protease (called SAPA) was produced (4600 U/mL) by Anoxybacillus kamchatkensis M1V, purified to homogeneity, and biochemically... 相似文献
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Messaouda Khallef Recep Liman Muhsin Konuk İbrahim Hakkı Ciğerci Djameleddine Benouareth Mouna Tabet Ahlem Abda 《Cytotechnology》2015,67(2):207-213
Genotoxic effects of bromoform and chloroform, disinfection by-products of the chlorination of drinking water, were examined by using mitotic index (MI), mitotic phase, chromosome aberrations (CAs) and comet assay on root meristematic cells of Allium cepa. Different concentrations of bromoform (25, 50, 75 and 100 μg/mL) and chloroform (25, 50, 100 and 200 μg/mL) were introduced to onion tuber roots. Distilled water was used as a negative control and methyl methansulfonate (MMS-10 μg/mL) as positive control. All obtained data were subjected to statistical analyses by using SPSS 15.0 for Windows software. For comparison purposes, Duncan multiple range tests by using one-way analysis of variance were employed and p < 0.05 was accepted as significant value. Exposure of both chemicals (except 25 μg/mL applications of bromoform) significantly decreased MI. Bromoform and chloroform (except 25 μg/mL applications) increased total CAs in Allium anaphase-telophase test. A significant increase in DNA damage was also observed at all concentrations of both bromoform and chloroform examined by comet assay. The damages were higher than that of positive control especially at 75–100 μg/mL for bromoform and 100–200 μg/mL for chloroform. 相似文献
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Mouna Tlili Hamlet Acevedo Albert Descoteaux Marc Germain Krista M. Heinonen 《The Journal of biological chemistry》2022,298(8)
Macrophages respond to their environment by adopting a predominantly inflammatory or anti-inflammatory profile, depending on the context. The polarization of the subsequent response is regulated by a combination of intrinsic and extrinsic signals and is associated with alterations in macrophage metabolism. Although macrophages are important producers of Wnt ligands, the role of Wnt signaling in regulating metabolic changes associated with macrophage polarization remains unclear. Wnt4 upregulation has been shown to be associated with tissue repair and suppression of age-associated inflammation, which led us to generate Wnt4-deficient bone marrow–derived macrophages to investigate its role in metabolism. We show that loss of Wnt4 led to modified mitochondrial structure, enhanced oxidative phosphorylation, and depleted intracellular lipid reserves, as the cells depended on fatty acid oxidation to fuel their mitochondria. Further we found that enhanced lipolysis was dependent on protein kinase C–mediated activation of lysosomal acid lipase in Wnt4-deficient bone marrow–derived macrophages. Although not irreversible, these metabolic changes promoted parasite survival during infection with Leishmania donovani. In conclusion, our results indicate that enhanced macrophage fatty acid oxidation impairs the control of intracellular pathogens, such as Leishmania. We further suggest that Wnt4 may represent a potential target in atherosclerosis, which is characterized by lipid storage in macrophages leading to them becoming foam cells. 相似文献
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Najla Mezghani Mouna Mnif Maha Kacem Emna Mkaouar-Rebai Ikhlass Hadj Salem Nozha Kallel Nadia charfi Mohamed Abid Faiza fakhfakh 《Biochemical and biophysical research communications》2011,(4):747
Mitochondrial encephalopathy, lactic acidosis and strokelike episodes (MELAS) syndrome is a mitochondrial disorder characterized by a wide variety of clinical presentations and a multisystemic organ involvement. In this study, we report a Tunisian girl with clinical features of MELAS syndrome who was negative for the common m.3243A>G mutation, but also for the reported mitochondrial DNA (mtDNA) mutations and deletions. Screening of the entire mtDNA genome showed several known mitochondrial variants besides to a novel transition m.1640A>G affecting a wobble adenine in the anticodon stem region of the tRNAVal. This nucleotide was conserved and it was absent in 150 controls suggesting its pathogenicity. In addition, no mutations were found in the nuclear polymerase gamma-1 gene (POLG1). These results suggest further investigation nuclear genes encoding proteins responsible for stability and structural components of the mtDNA or to the oxidative phosphorylation machinery to explain the phenotypic variability in the studied family. 相似文献
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We previously reported that Aspergillus oryzae strain S2 had produced two α-amylase isoforms named AmyA and AmyB. The apparent molecular masses revealed by SDS-PAGE were 50 and 42 kDa, respectively. Yet AmyB has a higher catalytic efficiency. Based on a monitoring study of the α-amylase production in both the presence and absence of different protease inhibitors, a chymotrypsin proteolysis process was detected in vivo generating AmyB. A. oryzae S2 α-amylase gene was amplified, cloned and sequenced. The sequence analysis revealed nine exons, eight introns and an encoding open reading frame of 1500 bp corresponding to AmyA isoform. The amino-acid sequence analysis revealed aY371 potential chymotrypsin cleaving site, likely to be the AmyB C-Terminal end and two other potential sites at Y359, and F379. A zymogram with a high acrylamide concentration was used. It highlighted two other closed apparent molecular mass α-amylases termed AmyB1 and AmyB2 reaching40 kDa and 43 kDa. These isoforms could be possibly generated fromY359, and F379secondary cut, respectively. The molecular modeling study showed that AmyB preserved the (β/α)8 barrel domain and the domain B but lacked the C-terminal domain C. The contact map analysis and the docking studies strongly suggested a higher activity and substrate binding affinity for AmyB than AmyA which was previously experimentally exhibited. This could be explained by the easy catalytic cleft accessibility. 相似文献
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Nas Fatima Aissaoui Nadia Mahjoubi Mouna Mosbah Amor Arab Mounia Abdelwahed Soukaina Khrouf Rim Masmoudi Ahmed-Salaheddine Cherif Ameur Klouche-Khelil Nihel 《International microbiology》2021,24(3):455-470
International Microbiology - The reemergence of infectious diseases and resistant pathogens represents a serious problem for human life. Hence, the screening for new or alternative antimicrobial... 相似文献
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Protein-protein interaction (PPI) network analysis has been considered as a useful approach to explore the mechanisms of complex diseases, such as cancer. To date, many proteins have been reported to involve in the development of cancer. Exploration of cancer proteins in the human PPI network may provide important biological information to uncover molecular mechanisms of cancer. Here, we have explored network characteristics (including degree, betweenness, clustering coefficient and shortest-path distance) of cancer proteins of the human nuclear and tyrosine kinases receptors network (NR-RTK) constructed in our earlier work. We found that the network topology of cancer proteins in this network have some specific features. Relative to the non-cancer proteins, the cancer proteins have likely higher degree, higher betweenness, similar clustering coefficient and similar shortest-path distance. Finally, we found that the cancer proteins were involved mainly in signalling pathways which dysfunction is directly related to cancer onset. These findings are helpful for cancer candidate protein prioritization and verification, and identification of key pathways involved in cancer disease. 相似文献
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