Synchronized infection of cell cultures by magnetically controlled virus.
Ontology highlight
ABSTRACT:
SUBMITTER: Haim H
PROVIDER: S-EPMC538731 | biostudies-other | 2005 Jan
REPOSITORIES: biostudies-other
Similar Datasets
Project description:Hantavirus pulmonary syndrome (HPS) is an acute disease resulting from infection with any one of a number of New World hantaviruses. HPS has a mortality rate of 40% and, unlike many other severe respiratory diseases, often occurs in young, healthy adults. Infection is usually initiated after inhalation of rodent excreta containing virus particles, but human-to-human transmission has been documented. Postmortem tissue samples show high levels of viral antigen within the respiratory endothelium, but it is not clear how the virus can traverse the respiratory epithelium in order to initiate infection in the microvasculature. We have utilized Andes virus infection of primary, differentiated airway epithelial cells to investigate the ability of the virus to interact with and cross the respiratory epithelium. Andes virus infects the Clara and goblet cell populations but not the ciliated cells, and this infection pattern corresponds to the expression of beta(3) integrin, the viral receptor. The virus can infect via the apical or basolateral membrane, and progeny virus particles are secreted bidirectionally. There is no obvious cytopathology associated with infection, and beta(3) integrins do not appear to be critical for respiratory epithelial cell monolayer integrity. Our data suggest that hantavirus infection of the respiratory epithelium may play an important role in the early or prodrome phase of disease as well as serving as a source of virus involved in transmission.
| S-EPMC1346943 | biostudies-literature
Project description:Microscopic swimming devices hold promise for radically new applications in lab-on-a-chip and microfluidic technology, diagnostics and drug delivery etc. In this paper, we demonstrate the experimental verification of a new class of autonomous ferromagnetic swimming devices, actuated and controlled solely by an oscillating magnetic field. These devices are based on a pair of interacting ferromagnetic particles of different size and different anisotropic properties joined by an elastic link and actuated by an external time-dependent magnetic field. The net motion is generated through a combination of dipolar interparticle gradient forces, time-dependent torque and hydrodynamic coupling. We investigate the dynamic performance of a prototype (3.6 mm) of the ferromagnetic swimmer in fluids of different viscosity as a function of the external field parameters (frequency and amplitude) and demonstrate stable propulsion over a wide range of Reynolds numbers. We show that the direction of swimming has a dependence on both the frequency and amplitude of the applied external magnetic field, resulting in robust control over the speed and direction of propulsion. This paves the way to fabricating microscale devices for a variety of technological applications requiring reliable actuation and high degree of control.
| S-EPMC5343437 | biostudies-literature
Project description:The cell cycle of the chlorophyll b-possessing marine cyanobacterium Prochlorococcus is highly synchronized under natural conditions. To understand the underlying molecular mechanisms we cloned and sequenced dnaA and ftsZ, two key cell cycle-associated genes, and studied their expression. An axenic culture of Prochlorococcus sp. strain PCC 9511 was grown in a turbidostat with a 12 h-12 h light-dark cycle for 2 weeks. During the light periods, a dynamic light regimen was used in order to simulate the natural conditions found in the upper layers of the world's oceans. This treatment resulted in strong cell cycle synchronization that was monitored by flow cytometry. The steady-state mRNA levels of dnaA and ftsZ were monitored at 4-h intervals during four consecutive division cycles. Both genes exhibited clear diel expression patterns with mRNA maxima during the replication (S) phase. Western blot experiments indicated that the peak of FtsZ concentration occurred at night, i.e., at the time of cell division. Thus, the transcript accumulation of genes involved in replication and division is coordinated in Prochlorococcus sp. strain PCC 9511 and might be crucial for determining the timing of DNA replication and cell division.
| S-EPMC94958 | biostudies-literature
Project description:Influenza A viruses (IAV) are commonly used to infect animal cell cultures for research purposes and vaccine production. Their replication is influenced strongly by the multiplicity of infection (MOI), which ranges over several orders of magnitude depending on the respective application. So far, mathematical models of IAV replication have paid little attention to the impact of the MOI on infection dynamics and virus yields. To address this issue, we extended an existing model of IAV replication in adherent MDCK cells with kinetics that explicitly consider the time point of cell infection. This modification does not only enable the fitting of high MOI measurements, but also the successful prediction of viral release dynamics of low MOI experiments using the same set of parameters. Furthermore, this model allows the investigation of defective interfering particle (DIP) propagation in different MOI regimes. The key difference between high and low MOI conditions is the percentage of infectious virions among the total virus particle release. Simulation studies show that DIP interference at a high MOI is determined exclusively by the DIP content of the seed virus while, in low MOI conditions, it is predominantly controlled by the de novo generation of DIPs. Overall, the extended model provides an ideal framework for the prediction and optimization of cell culture-derived IAV manufacturing and the production of DIPs for therapeutic use.
| S-EPMC6396949 | biostudies-literature
Project description:au13-11_gravity - gravity - Cell cycle and cell proliferation are decoupled under altered gravity conditions. We have previously shown that semisolid cell cultures of Arabidopsis suffer overall genome changes in response to altered gravity and also that cell cycle stages duration is altered. By using synchronized cell cultures we will demonstrate the precise alterations in cell cycle duration and also the transcriptional signature in any of them. - Experiments consists on exposures of Arabidopsis cell cultures to 1g control/simulated microgravity (RPM) conditions. Asynchronous cells exposed for 14 h + Syncronous populations choosen to have an enrichment of cell cycle phases were used (being T7/T10 samples on G2 phase, T14/T16 samples on G1 phase).
2014-08-23 | GSE60473 | GEO
Project description:Multiple steps of the life cycle of hepatitis B virus (HBV) are known to be coupled to hepatic metabolism. However, the details of involvement of the hepatic metabolic milieu in HBV infection remain incompletely understood. Hepatic lipid metabolism is controlled by a complicated transcription factor network centered on retinoid X receptor alpha (RXRα). Here, we report that RXRα negatively regulates HBV infection at an early stage in cell cultures. The RXR-specific agonist bexarotene inhibits HBV in HepG2 cells expressing the sodium taurocholate cotransporting polypeptide (NTCP) (HepG2-NTCP), HepaRG cells, and primary Tupaia hepatocytes (PTHs); reducing RXRα expression significantly enhanced HBV infection in the cells. Transcriptome sequencing (RNA-seq) analysis of HepG2-NTCP cells with a disrupted RXRα gene revealed that reduced gene expression in arachidonic acid (AA)/eicosanoid biosynthesis pathways, including the AA synthases phospholipase A2 group IIA (PLA2G2A), is associated with increased HBV infection. Moreover, exogenous treatment of AA inhibits HBV infection in HepG2-NTCP cells. These data demonstrate that RXRα is an important cellular factor in modulating HBV infection and implicate the participation of AA/eicosanoid biosynthesis pathways in the regulation of HBV infection.IMPORTANCE Understanding how HBV infection is connected with hepatic lipid metabolism may provide new insights into virus infection and its pathogenesis. By a series of genetic studies in combination with transcriptome analysis and pharmacological assays, we here investigated the role of cellular retinoid X receptor alpha (RXRα), a crucial transcription factor for controlling hepatic lipid metabolism, in de novo HBV infection in cell cultures. We found that silencing of RXRα resulted in elevated HBV covalently closed circular DNA (cccDNA) formation and viral antigen production, while activation of RXRα reduced HBV infection efficiency. Our results also showed that silencing phospholipase A2 group IIA (PLA2G2A), a key enzyme of arachidonic acid (AA) synthases, enhanced HBV infection efficiency in HepG2-NTCP cells and that exogenous AA treatment reduced de novo HBV infection in the cells. These findings unveil RXRα as an important cellular factor in modulating HBV infection and may point to a new strategy for host-targeted therapies against HBV.
| S-EPMC5874418 | biostudies-literature
Project description:Marine viruses are the most abundant biological entity in the ocean and are considered as major evolutionary drivers of microbial life [C. A. Suttle, Nat. Rev. Microbiol. 5, 801-812 (2007)]. Yet, we lack quantitative approaches to assess their impact on the marine ecosystem. Here, we provide quantification of active viral infection in the bloom forming single-celled phytoplankton Emiliania huxleyi infected by the large virus EhV, using high-throughput single-molecule messenger RNA in situ hybridization (smFISH) of both virus and host transcripts. In natural samples, viral infection reached only 25% of the population despite synchronized bloom demise exposing the coexistence of infected and noninfected subpopulations. We prove that photosynthetically active cells chronically release viral particles through nonlytic infection and that viral-induced cell lysis can occur without viral release, thus challenging major assumptions regarding the life cycle of giant viruses. We could also assess active infection in cell aggregates linking viral infection and carbon export to the deep ocean [C. P. Laber et al., Nat. Microbiol. 3, 537-547 (2018)] and suggest a potential host defense strategy by enrichment of infected cells in sinking aggregates. Our approach can be applied to diverse marine microbial systems, opening a mechanistic dimension to the study of biotic interactions in the ocean.
| S-EPMC7980383 | biostudies-literature
Project description:At present, in vitro phenotypic screening methods are widely used for drug discovery. In the field of epilepsy research, measurements of neuronal activities have been utilized for predicting efficacy of anti-epileptic drugs. Fluorescence measurements of calcium oscillations in neurons are commonly used for measurement of neuronal activities, and some anti-epileptic drugs have been evaluated using this assay technique. However, changes in waveforms were not quantified in previous reports. Here, we have developed a high-throughput screening system containing a new analysis method for quantifying waveforms, and our method has successfully enabled simultaneous measurement of calcium oscillations in a 96-well plate. Features of waveforms were extracted automatically and allowed the characterization of some anti-epileptic drugs using principal component analysis. Moreover, we have shown that trajectories in accordance with the concentrations of compounds in principal component analysis plots were unique to the mechanism of anti-epileptic drugs. We believe that an approach that focuses on the features of calcium oscillations will lead to better understanding of the characteristics of existing anti-epileptic drugs and allow to predict the mechanism of action of novel drug candidates.
| S-EPMC10146483 | biostudies-literature
Project description:This unit describes the maintenance of cell lines used with vaccinia virus, both in monolayer cultures and in suspension. The suspended cell culture is then used in the preparation of vaccinia virus stocks. The preparation of chick embryo fibroblasts (CEF) is also presented for use in the production of the highly attenuated and host range-restricted modified vaccinia virus Ankara (MVA) strain of vaccinia virus. Additionally, support protocols are presented for the titration of standard and MVA vaccinia virus stocks.
| S-EPMC5575744 | biostudies-literature
Project description:The culturing of cell lines used with vaccinia virus, both as monolayer and in suspension, is described. The preparation of chick embryo fibroblasts (CEF) is presented for use in the production of the highly attenuated and host range-restricted modified vaccinia virus Ankara (MVA) strain of vaccinia virus. Protocols for the preparation, titration, and trypsinization of vaccinia virus stocks, as well as viral DNA preparation and virus purification methods are also included.
| S-EPMC5081219 | biostudies-literature