Viral Infected Cells Reveal Distinct Polarization Behavior; A Polarimetric Microscopy Analysis on HSV Infected Vero and HeLa cells

2021 ◽  
pp. 107484
Author(s):  
Saeed Amiri ◽  
Mitra Abedini ◽  
Saeedesadat Badieyan ◽  
Maryam Vaezjalali ◽  
Omid Akhavan ◽  
...  
Keyword(s):  
Hela Cells ◽  
Polarization Behavior ◽  
Infected Cells ◽  
Microscopy Analysis

scholarly journals Brucella abortus Transits through the Autophagic Pathway and Replicates in the Endoplasmic Reticulum of Nonprofessional Phagocytes

1998 ◽  
Vol 66 (12) ◽  
pp. 5711-5724 ◽  
Author(s):  
Javier Pizarro-Cerdá ◽  
Stéphane Méresse ◽  
Robert G. Parton ◽  
Gisou van der Goot ◽  
Alberto Sola-Landa ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Hela Cells ◽  
Brucella Abortus ◽  
Cathepsin D ◽  
Bacterial Strains ◽  
Infected Cells ◽  
Bacterial Replication ◽  
Protein Disulfide ◽  
Intracellular Pathway ◽  
Replication Compartment

ABSTRACT Brucella abortus is an intracellular pathogen that replicates within a membrane-bounded compartment. In this study, we have examined the intracellular pathway of the virulent B. abortus strain 2308 (S2308) and the attenuated strain 19 (S19) in HeLa cells. At 10 min after inoculation, both bacterial strains are transiently detected in phagosomes characterized by the presence of early endosomal markers such as the early endosomal antigen 1. At ∼1 h postinoculation, bacteria are located within a compartment positive for the lysosome-associated membrane proteins (LAMPs) and the endoplasmic reticulum (ER) marker sec61β but negative for the mannose 6-phosphate receptors and cathepsin D. Interestingly, this compartment is also positive for the autophagosomal marker monodansylcadaverin, suggesting that S2308 and S19 are located in autophagic vacuoles. At 24 h after inoculation, attenuated S19 is degraded in lysosomes, while virulent S2308 multiplies within a LAMP- and cathepsin D-negative but sec61β- and protein disulfide isomerase-positive compartment. Furthermore, treatment of infected cells with the pore-forming toxin aerolysin from Aeromonas hydrophila causes vacuolation of the bacterial replication compartment. These results are compatible with the hypothesis that pathogenic B. abortus exploits the autophagic machinery of HeLa cells to establish an intracellular niche favorable for its replication within the ER.

scholarly journals Capped mRNAs with Reduced Secondary Structure Can Function in Extracts from Poliovirus-Infected Cells

1982 ◽  
Vol 2 (12) ◽  
pp. 1633-1638 ◽  
Author(s):  
Nahum Sonenberg ◽  
Denise Guertin ◽  
Kevin A. W. Lee
Keyword(s):  
Secondary Structure ◽  
Mosaic Virus ◽  
Hela Cells ◽  
Alfalfa Mosaic Virus ◽  
Stable Secondary Structure ◽  
Ribosome Binding ◽  
Infected Cells

Extracts from poliovirus-infected HeLa cells were used to study ribosome binding of native and denatured reovirus mRNAs and translation of capped mRNAs with different degrees of secondary structure. Here, we demonstrate that ribosomes in extracts from poliovirus-infected cells could form initiation complexes with denatured reovirus mRNA, in contrast to their inability to bind native reovirus mRNA. Furthermore, the capped alfalfa mosaic virus 4 RNA, which is most probably devoid of stable secondary structure at its 5′ end, could be translated at much higher efficiency than could other capped mRNAs in extracts from poliovirus-infected cells.

scholarly journals Characterization of Antiapoptotic Activities ofChlamydia pneumoniae in Human Cells

2001 ◽  
Vol 69 (11) ◽  
pp. 7121-7129 ◽  
Author(s):  
Silke F. Fischer ◽  
Claudia Schwarz ◽  
Juliane Vier ◽  
Georg Häcker
Keyword(s):  
Hela Cells ◽  
Chlamydia Pneumoniae ◽  
Death Receptor ◽  
Chronic Infections ◽  
Effector Caspase ◽  
Cellular Factors ◽  
Death Receptor Signaling ◽  
Infected Cells ◽  
External Stimuli ◽  
Bacterial Protein Synthesis

ABSTRACT Chlamydia pneumoniae is an obligate intracellular bacterium which frequently causes airway infection in humans and has been implicated in atherosclerosis. Here we show that infection withC. pneumoniae protects HeLa human epithelioid cells against apoptosis induced by external stimuli. In infected HeLa cells, apoptosis induced by staurosporine and CD95-death-receptor signaling was strongly reduced. Upon treatment with staurosporine, generation of effector caspase activity, processing of caspase-3 and caspase-9 and cytochrome c redistribution were all profoundly inhibited in cells infected with C. pneumoniae. Bacterial protein synthesis during early infection was required for this inhibition. Furthermore, cytochrome c-induced processing and activation of caspases were inhibited in cytosolic extracts from infected cells, suggesting that a C. pneumoniae-dependent antiapoptotic factor was generated in the cytosol upon infection. Infection with C. pneumoniaefailed to induce significant NF-κB activation in HeLa cells, indicating that no NF-κB-dependent cellular factors were involved in the protection against apoptosis. These results show that C. pneumoniae is capable of interfering with the host cell's apoptotic apparatus at probably at least two steps in signal transduction and might explain the propensity of these bacteria to cause chronic infections in humans.

scholarly journals The dynamics of coiled bodies in the nucleus of adenovirus-infected cells.

1996 ◽  
Vol 7 (7) ◽  
pp. 1137-1151 ◽  
Author(s):  
L Rebelo ◽  
F Almeida ◽  
C Ramos ◽  
K Bohmann ◽  
A I Lamond ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Hela Cells ◽  
Host Protein ◽  
Coiled Body ◽  
Adenovirus Infection ◽  
Protein Synthesis Inhibitors ◽  
Coiled Bodies ◽  
Infected Cells ◽  
Host Protein Synthesis ◽  
Small Nuclear Ribonucleoproteins

The coiled body is a specific intranuclear structure of unknown function that is enriched in splicing small nuclear ribonucleoproteins (snRNPs). Because adenoviruses make use of the host cell-splicing machinery and subvert the normal subnuclear organization, we initially decided to investigate the effect of adenovirus infection on the coiled body. The results indicate that adenovirus infection induces the disassembly of coiled bodies and that this effect is probably secondary to the block of host protein synthesis induced by the virus. Furthermore, coiled bodies are shown to be very labile structures, with a half-life of approximately 2 h after treatment of HeLa cells with protein synthesis inhibitors. After blocking of protein synthesis, p80 coilin was detected in numerous microfoci that do not concentrate snRNP. These structures may represent precursor forms of the coiled body, which goes through a rapid cycle of assembly/disassembly in the nucleus and requires ongoing protein synthesis to reassemble.

scholarly journals Persistent Chlamydia trachomatis Infection of HeLa Cells Mediates Apoptosis Resistance through a Chlamydia Protease-Like Activity Factor-Independent Mechanism and Induces High Mobility Group Box 1 Release

2011 ◽  
Vol 80 (1) ◽  
pp. 195-205 ◽  
Author(s):  
Jürgen Rödel ◽  
Christina Große ◽  
Hangxing Yu ◽  
Katharina Wolf ◽  
Gordon P. Otto ◽  
...  
Keyword(s):  
Chlamydia Trachomatis ◽  
Host Cell ◽  
Hela Cells ◽  
Persistent Infection ◽  
High Mobility ◽  
Apoptosis Resistance ◽  
Content Type ◽  
Activity Factor ◽  
Infected Cells ◽  
Ifn Γ

ABSTRACTIntracellular persistence ofChlamydia trachomatishas been implicated in the development of chronic infection that can result in pelvic inflammatory disease and tubal sterility. By inhibition of host cell apoptosis, chlamydiae have evolved a strategy to maintain the intracellular environment for replication and persistence. Both antiapoptotic host cell-derived factors and the chlamydial protease-like activity factor (CPAF) are involved inChlamydia-mediated apoptosis resistance. Here, we show that in HeLa cells infected with gamma interferon (IFN-γ)-induced persistentC. trachomatisserovar D, the expression of CPAF is downregulated, and proapoptotic protease substrates are not cleaved. Persistent infection protected HeLa cells from apoptosis when they were exposed to staurosporine. Small-interfering RNA-mediated inhibition of myeloid cell leukemia 1 (Mcl-1) protein upregulation sensitized persistently infected cells for apoptosis. The inhibitor of apoptosis protein 2 (IAP-2) seems not to be relevant in this context because IAP-2 protein was not induced in response to IFN-γ treatment. Although apoptosis was inhibited, persistent infection caused cell membrane disintegration, as measured by the increased release of cytokeratin 18 from HeLa cells. Moreover, persistently infected cells released significantly increased amounts of high mobility group box 1 (HMGB1) protein which represents a proinflammatory damage-associated pattern molecule. The data of this study suggest that cells infected with persistentC. trachomatisare protected from apoptosis independently of CPAF but may promote chronic inflammation through HMGB1 release.

scholarly journals Antimalarial Activities of Dermaseptin S4 Derivatives

2000 ◽  
Vol 44 (9) ◽  
pp. 2442-2451 ◽  
Author(s):  
Miriam Krugliak ◽  
Rina Feder ◽  
Vadim Y. Zolotarev ◽  
Leonid Gaidukov ◽  
Arie Dagan ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Antimalarial Activity ◽  
Underlying Mechanism ◽  
Trophozoite Stage ◽  
Fluorescence Confocal Microscopy ◽  
Infected Cells ◽  
Microscopy Analysis ◽  
Confocal Microscopy Analysis ◽  
Micromolar Range ◽  
Significant Growth Inhibition

ABSTRACT The hemolytic antimicrobial peptide dermaseptin S4 was recently shown to exert antimalarial activity. In this study, we attempted to understand the underlying mechanism(s) and identify derivatives with improved antimalarial activity. A number of dermaseptin S4 derivatives inhibited parasite growth with a 50% inhibitory concentration (IC50) in the micromolar range. Among these, the substituted S4 analog K4K20-S4 was the most potent (IC50 = 0.2 μM), while its shorter version, K4-S4(1–13)a, retained a considerable potency (IC50 = 6 μM). Both K4K20-S4 and K4-S4(1–13)a inhibited growth of the parasites more at the trophozoite stage than at the ring stage. Significant growth inhibition was observed after as little as 1 min of exposure to peptides and proceeded with nearly linear kinetics. The peptides selectively lysed infected red blood cells (RBC) while having a weaker effect on noninfected RBC. Thus, K4K20-S4 lysed trophozoites at concentrations similar to those that inhibited their proliferation, but trophozoites were >30-fold more susceptible than normal RBC to the lytic effect of K4K20-S4, the most hemolytic dermaseptin. The same trend was observed with K4-S4(1–13)a. The d isomers of K4K20-S4 or K4-S4(1–13)a were as active as the l counterparts, indicating that antimalarial activity of these peptides, like their membrane-lytic activity, is not mediated by specific interactions with a chiral center. Moreover, dissipation of transmembrane potential experiments with infected cells indicated that the peptides induce damage in the parasite's plasma membrane. Fluorescence confocal microscopy analysis of treated infected cells also indicated that the peptide is able to find its way through the complex series of membranes and interact directly with the intracellular parasite. Overall, the data showed that dermaseptins exert antimalarial activity by lysis of infected cells. Dermaseptin derivatives are also able to disrupt the parasite plasma membrane without harming that of the host RBC.

scholarly journals TECHNIQUES APPLICABLE TO COMPUTER-AIDED CYTOPHOTOMETRY IN VIROLOGY

1974 ◽  
Vol 22 (7) ◽  
pp. 577-582 ◽  
Author(s):  
VOLKER TER MEULEN ◽  
KLAUS KOSCHEL ◽  
HANS M. AUS ◽  
MATHILDA KAEKELL ◽  
WOLFGANG SCHOLZ
Keyword(s):  
Virus Replication ◽  
Cell Morphology ◽  
Hela Cells ◽  
Structural Changes ◽  
Poliomyelitis Virus ◽  
Computer Aided ◽  
Infected Cells

Computer-aided cytophotometry is a new tool in the analysis of virus-infected cells. Structural changes of the cell morphology can easily be recognized and interpreted by the analytic systems available. More specific biochemical events that occur during virus replication can in certain instances be recorded and recognized if well defined trace markers are applied. This is demonstrated on poliomyelitis virus-infected HeLa cells.

scholarly journals Localization of Cap-Binding Protein in Subcellular Fractions of HeLa Cells

1982 ◽  
Vol 2 (12) ◽  
pp. 1639-1643 ◽  
Author(s):  
Joanna L. Hansen ◽  
Diane O. Etchison ◽  
John W. B. Hershey ◽  
Ellie Ehrenfeld
Keyword(s):  
Hela Cells ◽  
Binding Protein ◽  
Sedimentation Coefficient ◽  
Subcellular Fractions ◽  
Cross Linking ◽  
Infected Cells ◽  
Cell Fractions

The 26,000-Mrcap-binding protein was analyzed by a cross-linking assay in cell fractions from uninfected and poliovirus-infected HeLa cells. Cap-binding protein was found in the postribosomal supernatant (S-200) and in the ribosomal salt wash. The cap-binding protein in the S-200 had a sedimentation coefficient of 5 to 7S and lacked the ability to restore translation in extracts of poliovirus-infected cells.

scholarly journals Induction of protection in mice against a respiratory challenge by a vaccine formulated with exosomes isolated from Chlamydia muridarum infected cells

npj Vaccines ◽  
2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Sukumar Pal ◽  
Yeva Mirzakhanyan ◽  
Paul Gershon ◽  
Delia F. Tifrea ◽  
Luis M. de la Maza
Keyword(s):  
Mass Spectrometry ◽  
Body Weight ◽  
Membrane Protein ◽  
Immune Responses ◽  
Hela Cells ◽  
Outer Membrane Protein ◽  
Chlamydia Muridarum ◽  
Infected Cells ◽  
Respiratory Challenge ◽  
Negative Controls

Abstract The goal of this study was to determine if exosomes, isolated from Chlamydia muridarum infected HeLa cells (C. muridarum-exosomes), induce protective immune responses in mice following vaccination using CpG plus Montanide as adjuvants. Exosomes, collected from uninfected HeLa cells and PBS, formulated with the same adjuvants, were used as negative controls. Mass spectrometry analyses identified 113 C. muridarum proteins in the C. muridarum-exosome preparation including the major outer membrane protein and the polymorphic membrane proteins. Vaccination with C. muridarum-exosomes elicited robust humoral and cell-mediated immune responses to C. muridarum elementary bodies. Following vaccination, mice were challenged intranasally with C. muridarum. Compared to the negative controls, mice immunized with C. muridarum-exosomes were significantly protected as measured by changes in body weight, lungs’ weight, and number of inclusion forming units recovered from lungs. This is the first report, of a vaccine formulated with Chlamydia exosomes, shown to elicit protection against a challenge.

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