Cytochemistry of the wall of infected cells in Casuarina actinorhizae

1988 ◽  
Vol 66 (10) ◽  
pp. 2038-2047 ◽  
Author(s):  
R. Howard Berg ◽  
Lorraine McDowell
Keyword(s):  
Infected Cell ◽  
Secondary Wall ◽  
Chromic Acid ◽  
Cortical Cell ◽  
Wall Material ◽  
Primary Cell Wall ◽  
Acid Digestion ◽  
En Bloc ◽  
Lignin Modification ◽  
Infected Cells

Development of the wall of infected cells in Casuarina actinorhizae differs from that of many actinorhizae. After the endophyte penetrates the wall of a cortical cell, that (primary) cell wall becomes lignified, based on histochemical (autofluorescence, phloroglucinol staining) and cytochemical (permanganate staining, enzyme etching) evidence. Subsequently, the remaining walls of the infected cell become lignified. Adjacent noninfected cells somehow are stimulated to deposit a lignified secondary wall only on those walls bordering the infected cell. This remarkable participation of all adjacent noninfected cells in the development of a given infected cell results in an increased thickness and strength of the wall material surrounding infected cells. When they mature, there is a further modification of some of the wall layers surrounding infected cells, manifested in a relative impermeability to en bloc staining with permanganate. Unlike lignified walls, the permanganate-impermeable region is selectively stained by osmium or ferricyanide-reduced osmium and is relatively resistant to concentrated chromic acid digestion. A region that remains permeable to (and stained by) permanganate (part of the secondary wall of bordering noninfected cells) may be developmentally related to phi thickenings. An earlier contention that the permanganate-impermeable region contains suberin is unconfirmed. This region is most likely an unusual lignin modification or results from unidentified material impregnated in its ligninlike matrix.

Preliminary evidence for the involvement of suberization in infection of Casuarina

1983 ◽  
Vol 61 (11) ◽  
pp. 2910-2918 ◽  
Author(s):  
R. Howard Berg
Keyword(s):  
Chromic Acid ◽  
Hydrolytic Enzymes ◽  
Preliminary Evidence ◽  
Host Cells ◽  
Infected Host ◽  
Tissue Cell ◽  
En Bloc ◽  
Sudan Black B ◽  
Infected Cells ◽  
Mature Nodule

Histochemistry of infected cells in mature nodule lobes of Casuarina showed that walls of infected host cells had a ligninlike component (ultraviolet-stimulated autofluorescence and staining with auramine O, phloroglucinol staining, and resistance to degradation by hydrolytic enzymes). Cytoplasm of infected cells had a pronounced affinity for lipid stains (Sudan black B, Rose Bengal fluorescence), though walls of infected cells were less clearly stained. When nodules were digested several days in cold 50% chromic acid, the walls of infected cells and suberized host tissue (epidermis, endodermis) were not degraded. Endophyte cell wall components were also found to be resistant to chromic acid digestion. The digested tissue retained the capacity to adsorb lipid dyes. These observations suggested that walls of infected host cells had become impregnated with a suberinlike compound. The hydrophobic quality of this wall was evident when its ultrastructure was examined after en bloc staining with the polar stain KMnO4. This stain did not penetrate the walls of mature infected cells, perhaps because of the presence of aliphatic compounds similar to those found in suberin. As is known for suberizing tissue, peroxidase activity (via diaminobenzidine oxidation) was high in nodule cortical tissue cell walls. The peroxidase stain was also localized on endophyte hyphae. This report is the first instance associating a suberizationlike host reaction with infection of an actinorhizal plant.

Further Observations on the Virus of Epizootic Diarrhea of Infant Mice. An Electron Microscopic Study

1967 ◽  
Vol 25 ◽  
pp. 110-111
Author(s):  
W. G. Banfield ◽  
G. Kasnic ◽  
J. H. Blackwell
Keyword(s):  
Electron Microscope ◽  
Infected Cell ◽  
Microscopic Study ◽  
Intestinal Epithelium ◽  
Ultrastructural Study ◽  
Osmium Tetroxide ◽  
Lead Citrate ◽  
Electron Microscopic ◽  
Virus Particles ◽  
Infected Cells

An ultrastructural study of the intestinal epithelium of mice infected with the agent of epizootic diarrhea of infant mice (EDIM virus) was first performed by Adams and Kraft. We have extended their observations and have found developmental forms of the virus and associated structures not reported by them.Three-day-old NLM strain mice were infected with EDIM virus and killed 48 to 168 hours later. Specimens of bowel were fixed in glutaraldehyde, post fixed in osmium tetroxide and embedded in epon. Sections were stained with uranyl magnesium acetate followed by lead citrate and examined in an updated RCA EMU-3F electron microscope.The cells containing virus particles (infected) are at the tips of the villi and occur throughout the intestine from duodenum through colon. All developmental forms of the virus are present from 48 to 168 hours after infection. Figure 1 is of cells without virus particles and figure 2 is of an infected cell. The nucleus and cytoplasm of the infected cells appear clearer than the cells without virus particles.

An ultrastructural study of acid phosphatase localization in Phaseolus vulgaris xylem by the use of an azo-dye method

1975 ◽  
Vol 19 (3) ◽  
pp. 543-561
Author(s):  
I. Charvat ◽  
K. Esau
Keyword(s):  
Acid Phosphatase ◽  
Phaseolus Vulgaris ◽  
Azo Dye ◽  
Secondary Wall ◽  
Parenchyma Cell ◽  
Middle Lamella ◽  
Primary Cell Wall ◽  
Vessel Element ◽  
Primary Wall ◽  
Final Reaction

The localization of acid phosphatase during xylem development has been examined in the bean, Phaseolus vulgaris. The azo dye, the final reaction product, is initially prominent in the dictyosomes, vesicles apparently participating in secondary wall formation, and in the middle lamella of the young vessel element. Final reaction particles are also present in mitochondria, chloroplasts, and certain vacuoles and are sparsely scattered in the cytoplasm. At a later stage of vessel differentiation, the azo dye is concentrated in the disintegrating cytoplasm and along the fibrils of the partially hydrolysed primary wall and middle lamella. In the mature vessel element, the azo dye is still present along the disintegrated primary wall at the side of the vessel and covers the secondary wall. In the parenchyma cell adjacent to the vessel element, acid phosphatase localization is found in the dictyosomes, endoplasmic reticulum, mitochondria, small vacuoles, and the middle lamella. The controls from all stages of vessel element development were free of azo dye particles. The concentration of acid phosphatase along the secondary walls of the mature vessels and in the middle lamella between other cells indicates that this enzyme has other functions besides autolysis of the cytoplasm and primary cell wall. Acid phosphatase may participate in the formation of the secondary wall and may also have a role in the secretion and transport of sugars.

An RNA polymerase II transcription factor inactivated in poliovirus-infected cells copurifies with transcription factor TFIID

1988 ◽  
Vol 8 (8) ◽  
pp. 3175-3182
Author(s):  
S Kliewer ◽  
A Dasgupta
Keyword(s):  
Transcription Factor ◽  
Infected Cell ◽  
Rna Polymerase ◽  
Host Cell ◽  
Rna Polymerase Ii ◽  
Heat Inactivation ◽  
Early Event ◽  
Cell Extracts ◽  
Infected Cells ◽  
Rna Polymerase Ii Transcription

Inhibition of host cell RNA polymerase II-mediated transcription by poliovirus infection was studied in vitro. Whole-cell extracts prepared from poliovirus-infected HeLa cells at 3 h postinfection were shown to be deficient in a factor required for specific transcription from the adenovirus major late promoter. Three lines of evidence suggest that transcription factor TFIID is deficient in poliovirus-infected cells. First, the activity required to specifically restore transcription in poliovirus-infected cell extracts was shown to copurify with TFIID through three chromatographic steps. Second, transcription reactions reconstituted with phosphocellulose-derived chromatographic fractions revealed a fourfold decrease in the specific activity of the TFIID-containing fraction prepared from poliovirus-infected cells compared with that of the same fraction prepared from mock-infected cells. Finally, TFIID and the activity required to specifically restore transcription in virus-infected cell extracts were shown to have the same kinetics of heat inactivation. Together, these results suggest that inactivation of TFIID is an early event in the inhibition of host cell RNA polymerase II transcription by poliovirus.

scholarly journals A Role for Single-Stranded Templates in Cell-Free Adeno-Associated Virus DNA Replication

2000 ◽  
Vol 74 (2) ◽  
pp. 744-754 ◽  
Author(s):  
Peter Ward ◽  
R. Michael Linden
Keyword(s):  
Dna Replication ◽  
Infected Cell ◽  
Dna Binding Protein ◽  
Strand Displacement ◽  
Dna Templates ◽  
Single Stranded Dna ◽  
Adeno Associated Virus ◽  
Rep Protein ◽  
Cell Extracts ◽  
Infected Cells

ABSTRACT Assays have been described in which duplex adeno-associated virus (AAV) DNA can be replicated in HeLa cell extracts with exogenous AAV Rep protein. These assays appear to mimic the AAV DNA replication that occurs in the cell, including the ability of extracts from adenovirus (Ad)-infected cells to replicate duplex AAV DNA templates more efficiently than extracts from uninfected cells can. We showed previously that the Ad-infected extract was able to support a more processive replication than the uninfected extract. When the Ad single-stranded DNA binding protein (Ad-DBP) was added to an uninfected extract, DNA replication became processive. Based on a strand displacement replication model, we hypothesized that the Ad-DBP was stabilizing the displaced single-stranded DNA during strand displacement replication. In this report, we show that in Ad-infected extracts most of the newly replicated duplex DNA is converted into a single-stranded form shortly after synthesis. Using the results of assays for the replication of single-stranded AAV DNA, we show that these single-stranded molecules serve as templates for additional replication. In addition, we identify a class of molecules which are likely to be intermediates of replication on single-stranded templates. We discuss a possible role for replication of single-stranded molecules in the infected cell.

scholarly journals Generating Aptamers for Recognition of Virus-Infected Cells

2009 ◽  
Vol 55 (4) ◽  
pp. 813-822 ◽  
Author(s):  
Zhiwen Tang ◽  
Parag Parekh ◽  
Pete Turner ◽  
Richard W Moyer ◽  
Weihong Tan
Keyword(s):  
Infected Cell ◽  
Vaccinia Virus ◽  
Dissociation Constants ◽  
A549 Cells ◽  
Molecular Probes ◽  
Dna Aptamer ◽  
Live Cells ◽  
Selection Strategy ◽  
Infected Cells ◽  
Equilibrium Dissociation Constants

Abstract Background: The development of molecular probes capable of recognizing virus-infected cells is essential to meet the serious clinical, therapeutic, and national-security challenges confronting virology today. We report the development of DNA aptamers as probes for the selective targeting of virus-infected living cells. Methods: To create aptamer probes capable of recognizing virus-infected cells, we used cell-SELEX (systematic evolution of ligands via exponential enrichment), which uses intact infected live cells as targets for aptamer selection. In this study, vaccinia virus–infected and –uninfected lung cancer A549 cells were chosen to develop our model probes. Results: A panel of aptamers has been evolved by means of the infected cell–SELEX procedure. The results demonstrate that the aptamers bind selectively to vaccinia virus–infected A549 cells with apparent equilibrium dissociation constants in the nanomolar range. In addition, these aptamers can specifically recognize a variety of target infected cell lines. The aptamers’ target is most likely a viral protein located on the cell surface. Conclusions: The success of developing a panel of DNA-aptamer probes capable of recognizing virus-infected cells via a whole living cell–SELEX selection strategy may increase our understanding of the molecular signatures of infected cells. Our findings suggest that aptamers can be developed as molecular probes for use as diagnostic and therapeutic reagents and for facilitating drug delivery against infected cells.

scholarly journals Dynamically linking influenza virus infection kinetics, lung injury, inflammation, and disease severity

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Margaret A Myers ◽  
Amanda P Smith ◽  
Lindey C Lane ◽  
David J Moquin ◽  
Rosemary Aogo ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Lung Injury ◽  
Infected Cell ◽  
Disease Severity ◽  
Influenza Virus Infection ◽  
Influenza Viruses ◽  
Cell Dynamics ◽  
Cell Clearance ◽  
Infected Cells

Influenza viruses cause a significant amount of morbidity and mortality. Understanding host immune control efficacy and how different factors influence lung injury and disease severity are critical. We established and validated dynamical connections between viral loads, infected cells, CD8+ T cells, lung injury, inflammation, and disease severity using an integrative mathematical model-experiment exchange. Our results showed that the dynamics of inflammation and virus-inflicted lung injury are distinct and nonlinearly related to disease severity, and that these two pathologic measurements can be independently predicted using the model-derived infected cell dynamics. Our findings further indicated that the relative CD8+ T cell dynamics paralleled the percent of the lung that had resolved with the rate of CD8+ T cell-mediated clearance rapidly accelerating by over 48,000 times in 2 days. This complimented our analyses showing a negative correlation between the efficacy of innate and adaptive immune-mediated infected cell clearance, and that infection duration was driven by CD8+ T cell magnitude rather than efficacy and could be significantly prolonged if the ratio of CD8+ T cells to infected cells was sufficiently low. These links between important pathogen kinetics and host pathology enhance our ability to forecast disease progression, potential complications, and therapeutic efficacy.

scholarly journals A computational technique to estimate within-host productively infected cell lifetimes in emerging viral infections

2016 ◽  
Author(s):  
Soumya Banerjee
Keyword(s):  
Infected Cell ◽  
Viral Infections ◽  
Cell Types ◽  
Emerging Diseases ◽  
Computational Technique ◽  
Emerging Viruses ◽  
Novel Technique ◽  
Differential Equation Models ◽  
Infected Cells ◽  
Health Relevance

Emerging viruses cause a lot of fatalities as they jump to humans from other species. Here we develop a novel technique to computationally estimate an important parameter of within-host viral infection: the lifespan of infected cells. Our approach is general and can be applied to a large class of viruses and leverages experimental data from replicon studies. Current techniques have difficulties reliably estimating infected cell lifetimes due to issues of parameter identifiability and correlation of parameters. The infected cell lifetime is an important parameter that gives an estimate of the how fast virus levels will decline. Our method would also help determine if some infected cells are short-lived or have longer lifespans with the consequence that longer lived cells could be reservoirs of infection. This would give a mechanistic understanding of why particular cell types are reservoirs of infection. We apply our technique to West Nile virus (WNV), an emerging disease of public health relevance related to Zika virus. Our analysis suggests that the most abundant infectible cells are short-lived and could motivate therapy that targets these particular cells. Our approach is very general and can be combined with more traditional methods of using differential equation models to simulate viremia in hosts: the combination of these two techniques will likely yield results that may not be achievable using the models in isolation. This will be of great interest especially in modelling emerging diseases.

scholarly journals Stable integrant-specific differences in bimodal HIV-1 expression patterns revealed by high-throughput analysis

2019 ◽  
Author(s):  
David F. Read ◽  
Edmond Atindaana ◽  
Kalyani Pyaram ◽  
Feng Yang ◽  
Sarah Emery ◽  
...  
Keyword(s):  
Gene Expression ◽  
Infected Cell ◽  
High Throughput ◽  
Expression Patterns ◽  
Clonal Expansion ◽  
High Throughput Analysis ◽  
Integration Sites ◽  
Infected Cells ◽  
Hiv 1 ◽  
Over Time

AbstractHIV-1 gene expression is regulated by host and viral factors that interact with viral motifs and is influenced by proviral integration sites. Here, expression variation among integrants was followed for hundreds of individual proviral clones within polyclonal populations throughout successive rounds of virus and cultured cell replication. Initial findings in immortalized cells were validated using CD4+ cells from donor blood. Tracking clonal behavior by proviral “zip codes” indicated that mutational inactivation during reverse transcription was rare, while clonal expansion and proviral expression states varied widely. By sorting for provirus expression using a GFP reporter in thenefopen reading frame, distinct clone-specific variation in on/off proportions were observed that spanned three orders of magnitude. Tracking GFP phenotypes over time revealed that as cells divided, their progeny alternated between HIV transcriptional activity and non-activity. Despite these phenotypic oscillations, the overall GFP+ population within each clone was remarkably stable, with clones maintaining clone-specific equilibrium mixtures of GFP+ and GFP-cells. Integration sites were analyzed for correlations between genomic features and the epigenetic phenomena described here. Integrants inserted in genes’ sense orientation were more frequently found to be GFP negative than those in the antisense orientation, and clones with high GFP+ proportions were more distal to repressive H3K9me3 peaks than low GFP+ clones. Clones with low frequencies of GFP positivity appeared to expand more rapidly than clones for which most cells were GFP+, even though the tested proviruses were Vpr-. Thus, much of the increase in the GFP-population in these polyclonal pools over time reflected differential clonal expansion. Together, these results underscore the temporal and quantitative variability in HIV-1 gene expression among proviral clones that are conferred in the absence of metabolic or cell-type dependent variability, and shed light on cell-intrinsic layers of regulation that affect HIV-1 population dynamics.SummaryVery few HIV-1 infected cells persist in patients for more than a couple days, but those that do pose life-long health risks. Strategies designed to eliminate these cells have been based on assumptions about what viral properties allow infected cell survival. However, such approaches for HIV-1 eradication have not yet shown therapeutic promise, possibly because much of the research underlying assumptions about virus persistence has been focused on a limited number of infected cell types, the averaged behavior of cells in diverse populations, or snapshot views. Here, we developed a high-throughput approach to study hundreds of distinct HIV-1 infected cells and their progeny over time in an unbiased way. This revealed that each virus established its own pattern of gene expression that, upon infected cell division, was stably transmitted to all progeny cells. Expression patterns consisted of alternating waves of activity and inactivity, with the extent of activity differing among infected cell families over a 1000-fold range. The dynamics and variability among infected cells and within complex populations that the work here revealed has not previously been evident, and may help establish more accurate correlates of persistent HIV-1 infection.

scholarly journals A BMPR2/YY1 Signaling Axis Is Required for Human Cytomegalovirus Latency in Undifferentiated Myeloid Cells

mBio ◽  
2021 ◽  
Author(s):  
Emma Poole ◽  
Maria Cristina Carlan da Silva ◽  
Chris Huang ◽  
Marianne Perera ◽  
Sarah Jackson ◽  
...  
Keyword(s):  
Infected Cell ◽  
Severe Disease ◽  
Virus Reactivation ◽  
Therapeutic Targeting ◽  
Undifferentiated Cells ◽  
Latently Infected ◽  
Signaling Axis ◽  
Infected Cells ◽  
Immune Detection ◽  
Transcription Program

Understanding the mechanisms which regulate HCMV latency could allow therapeutic targeting of the latent virus reservoir from where virus reactivation can cause severe disease. We show that the BMPR2/TGFbeta receptor/YY1 signaling axis is crucial to maintain HCMV latency in undifferentiated cells and that pharmacological reduction of BMPR2 in latently infected cells leads to reactivation of the viral lytic transcription program, which renders the infected cell open to immune detection and clearance in infected individuals.

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