scholarly journals A Spotlight on Viruses—Application of Click Chemistry to Visualize Virus-Cell Interactions

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 481 ◽  
Author(s):  
Thorsten Müller ◽  
Volkan Sakin ◽  
Barbara Müller
Keyword(s):  
Click Chemistry ◽  
Defense Mechanisms ◽  
Fluorescent Labeling ◽  
Cell Interactions ◽  
Fluorescent Label ◽  
Host Interactions ◽  
Future Challenges ◽  
Genetic Code Expansion ◽  
Single Virus Tracking ◽  
Microscopy Techniques

The replication of a virus within its host cell involves numerous interactions between viral and cellular factors, which have to be tightly controlled in space and time. The intricate interplay between viral exploitation of cellular pathways and the intrinsic host defense mechanisms is difficult to unravel by traditional bulk approaches. In recent years, novel fluorescence microscopy techniques and single virus tracking have transformed the investigation of dynamic virus-host interactions. A prerequisite for the application of these imaging-based methods is the attachment of a fluorescent label to the structure of interest. However, their small size, limited coding capacity and multifunctional proteins render viruses particularly challenging targets for fluorescent labeling approaches. Click chemistry in conjunction with genetic code expansion provides virologists with a novel toolbox for site-specific, minimally invasive labeling of virion components, whose potential has just recently begun to be exploited. Here, we summarize recent achievements, current developments and future challenges for the labeling of viral nucleic acids, proteins, glycoproteins or lipids using click chemistry in order to study dynamic processes in virus-cell interactions.

Spontaneous leukocyte rolling in venules in untraumatized skin of conscious and anesthetized animals

1994 ◽  
Vol 267 (3) ◽  
pp. H1199-H1204 ◽  
Author(s):  
G. H. Janssen ◽  
G. J. Tangelder ◽  
M. G. Oude Egbrink ◽  
R. S. Reneman
Keyword(s):  
Defense Mechanisms ◽  
Fluorescent Labeling ◽  
Leukocyte Rolling ◽  
Rolling Velocity ◽  
Conscious Rats ◽  
Swiss Mice ◽  
Anesthetized Rats ◽  
Mouse Ear ◽  
Rats And Mice

Intravital bright-field videomicroscopy was used to investigate whether leukocyte rolling can be observed under normal physiological conditions. We studied skin venules in trained conscious rats and anesthetized rats and mice without touching the skin itself. Leukocyte rolling was spontaneously present in all hindpaw venules of Lewis rats (diam 8-27 microns) and also in all mouse ear venules (Swiss, 13-38 microns; BALB/c, 12-56 microns). Rolling levels (in leukocytes/min, median and range) were 8 (3-15) in conscious rats, 9 (3-19) in anesthetized rats, 30 (5-160) in anesthetized Swiss mice, and 10 (3-22) in anesthetized BALB/c mice. These levels appeared to be independent of time. Noninvasive mechanical stimulation induced an average increase of 32%. Fluorescent labeling of leukocytes in vivo with acridine orange had no influence. In Swiss mice, the rolling velocity was < 50 microns/s for > 75% of the leukocytes (median 31 microns/s); this parameter did not correlate with reduced velocity (17-68 s-1) and hence wall shear rate. Our finding that leukocyte rolling is spontaneously present in skin venules of anesthetized and conscious animals suggests a constant vigilance of the host defense mechanisms in the skin.

scholarly journals Isolation of a TRAIL Antagonist from the Serum of HIV-infected Patients

2011 ◽  
Vol 286 (41) ◽  
pp. 35742-35754 ◽  
Author(s):  
David J. Schnepple ◽  
Brett Shepard ◽  
Gary D. Bren ◽  
Nathan W. Cummins ◽  
Sekar Natesampillai ◽  
...  
Keyword(s):  
Hiv Infection ◽  
Defense Mechanisms ◽  
Receptor Interaction ◽  
Adaptive Mechanism ◽  
Apoptosis Resistance ◽  
Host Interactions ◽  
Adaptive Mechanisms ◽  
Trail Receptors ◽  
Infected Cells ◽  
Selection Of

Virus-host interactions are characterized by the selection of adaptive mechanisms by which to evade pathogenic and defense mechanisms, respectively. In primary T cells infected with HIV, HIV infection up-regulates TNF-related apoptosis inducing ligand (TRAIL) and death-inducing TRAIL receptors, but blockade of TRAIL:TRAIL receptor interaction does not alter HIV-induced cell death. Instead, HIV infection results in a novel splice variant that we call TRAIL-short (TRAIL-s), which antagonizes TRAIL-R2. In HIV patients, plasma TRAIL-s concentration increases with increasing viral load and renders cells resistant to TRAIL-induced death. Knockdown of TRAIL-s abrogates this resistance. We propose that TRAIL-s is a novel adaptive mechanism of apoptosis resistance acquired by HIV-infected cells to avoid their elimination by TRAIL-dependent effector mechanism.

scholarly journals Where does the peanut smut pathogen, Thecaphora frezii, fit in the spectrum of smut diseases?

Plant Disease ◽  
2021 ◽  
Author(s):  
Silvina Arias ◽  
Verónica Sofía Mary ◽  
Pilar Andrea Velez ◽  
María Gisel Rodriguez ◽  
Santiago Nicolás Otaiza González ◽  
...  
Keyword(s):  
South America ◽  
Pest Control ◽  
Food Quality ◽  
Defense Mechanisms ◽  
Management Strategies ◽  
Ustilago Maydis ◽  
Immune Defense ◽  
Smut Fungi ◽  
Host Interactions ◽  
Commercial Species

Smut fungi, such as Ustilago maydis, have been studied extensively as a model for plant- pathogenic basidiomycetes. However, little attention has been paid to smut diseases of agronomic importance that are caused by species of the fungus Thecaphora spp., probably due to their more localized distribution. Peanut smut by T. frezii has been reported only in South America, with Argentina being the only country where this disease has been noted in commercial species. In this work, important advances in deciphering T. frezii specific biology/pathobiology in relation to the agronomically relevant potato (T. solani), wheat (U. tritici) and barley (U. nuda) smuts are presented. The state of knowledge of fungal effectors, functionally characterized to date in U. maydis and most recently in T. thlaspeos, as well as the potential to be present in other Thecaphora species involved in dicot-host interactions like T. frezii-peanut, is summarized. We also discuss the applicability and limitations of current available methods for the identification of smut fungi in different matrices, and the management strategies to reduce their impact on the agri-food quality. To conclude, we describe some of the challenges in elucidating T. frezii strategies which allow it to successfully infect the host, and tolerate or evade plant immune defense mechanisms, as well as analysis of other aspects related to pest control and their implications for human health.

scholarly journals Recent advances in imaging subcellular processes

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 1553 ◽  
Author(s):  
Kenneth A. Myers ◽  
Christopher Janetopoulos
Keyword(s):  
Cell Biology ◽  
Fluorescent Labeling ◽  
Imaging Systems ◽  
Optical Techniques ◽  
Dynamic Architecture ◽  
Subcellular Processes ◽  
A Cell ◽  
Molecular Cell Biology ◽  
Microscopy Techniques ◽  
Microscopic Techniques

Cell biology came about with the ability to first visualize cells. As microscopy techniques advanced, the early microscopists became the first cell biologists to observe the inner workings and subcellular structures that control life. This ability to see organelles within a cell provided scientists with the first understanding of how cells function. The visualization of the dynamic architecture of subcellular structures now often drives questions as researchers seek to understand the intricacies of the cell. With the advent of fluorescent labeling techniques, better and new optical techniques, and more sensitive and faster cameras, a whole array of questions can now be asked. There has been an explosion of new light microscopic techniques, and the race is on to build better and more powerful imaging systems so that we can further our understanding of the spatial and temporal mechanisms controlling molecular cell biology.

Oblique-Incidence Reflectivity Difference and Fluorescence Imaging of Oligonucleotide and IgG Protein Microarrays

2003 ◽  
Vol 773 ◽  
Author(s):  
James P. Landry ◽  
X. D. Zhu ◽  
X. W. Guo ◽  
J. P. Gregg
Keyword(s):  
Oblique Incidence ◽  
Protein Microarrays ◽  
Fluorescent Labeling ◽  
Fluorescent Label ◽  
Label Free ◽  
Detection Techniques ◽  
Glass Substrates ◽  
Standard Glass ◽  
Non Destructive ◽  
Microarray Detection

AbstractWe have constructed an oblique-incidence reflectivity difference (OI-RD) microscope for fluorescent label-free imaging of DNA and protein microarrays on standard glass substrates. Using both OI-RD and fluorescence images, we demonstrate a difference in wetting behavior of labeled and unlabeled IgG protein molecules deposited on an aldehyde-derivatized glass surface. The potential of fluorescent labeling agents to influence the properties of proteins highlights the need for label-free microarray detection techniques to supplement existing fluorescence methods. We also present OI-RD images of an oligonucleotide microarray after printing and washing procedures to demonstrate the use of OI-RD for non-destructive monitoring of changes in the optical properties of microarrays during processing.

scholarly journals R-phycoerythrin as a fluorescent label for immunolocalization of bound atrazine residues.

1991 ◽  
Vol 39 (7) ◽  
pp. 921-926 ◽  
Author(s):  
G Sohn ◽  
C Sautter
Keyword(s):  
Indirect Immunofluorescence ◽  
Binding Sites ◽  
Aquatic Macrophytes ◽  
Elodea Canadensis ◽  
Fluorescent Labeling ◽  
Fluorescent Label ◽  
Nonspecific Binding ◽  
Immunofluorescence Method ◽  
Rabbit Igg ◽  
Highly Sensitive

We established a highly sensitive immunofluorescence procedure for localizing bound atrazine in the aquatic macrophytes Elodea canadensis and E. densa. The technique included biotin-labeled anti-rabbit IgG as a first enhancement step and R-phycoerythrin (R-PE) coupled to streptavidin for fluorescent labeling as a second improvement on the procedure. A comparison with the conventional indirect immunofluorescence method confirmed the superior results of the R-PE approach. The use of atrazine-free plants (grown in charcoal-filtered water) and a variety of other controls excluded both contaminating atrazine and nonspecific incubation constituents as sources of tissue staining. Pre-incubations to block nonspecific binding sites proved to be unnecessary in this system. The highly sensitive procedure described here might be a useful tool for the localization of tissue-bound pesticides in general and possibly of other haptens as well.

scholarly journals The chemical biology of coronavirus host–cell interactions

2021 ◽  
Author(s):  
Suprama Datta ◽  
Erik C. Hett ◽  
Kalpit A. Vora ◽  
Daria J. Hazuda ◽  
Rob C. Oslund ◽  
...  
Keyword(s):  
Host Cell ◽  
Chemical Biology ◽  
Molecular Level ◽  
Cell Interactions ◽  
Host Interactions ◽  
Host Cell Interactions

Chemical biology strategies can play important roles in studying the complexity of SARS-CoV-2–host interactions at molecular level detail.

scholarly journals COVID-19 and Crosstalk between the Hallmarks of Aging

2020 ◽  
Author(s):  
Shabnam Salimi ◽  
John M. Hamlyn
Keyword(s):  
Older Adults ◽  
Defense Mechanisms ◽  
Kidney Injury ◽  
Severe Pneumonia ◽  
Telomere Attrition ◽  
Host Interactions ◽  
Severity Of The Disease ◽  
Health Complications ◽  
Potential Interactions ◽  
Complications And Mortality

Within the past several decades, the emergence of new viral diseases with more severe health complications and mortality, primarily in older adults with comorbidities, is evidence of an age-dependent, compromised bodily response to abrupt stress with concomitant reduced immunity. The emergence of new infectious coronaviruses such as SARS-CoV-2 has resulted in the coronavirus disease 2019 (COVID-19). The result is increased morbidity and mortality in persons with underlying chronic diseases and among those with compromised defense mechanisms, regardless of age and among older adults who are more likely to fit these categories. COVID-19 appears to be primarily an upper respiratory disease. While SARS-CoV-2 is highly virulent, there is variability in the severity of the disease and its complications in humans. Severe pneumonia, acute respiratory distress syndrome (ARDS), lung fibrosis, cardiac t complication, acute kidney injury, hospitalization, and high mortality have been reported in older adults with COVID-19, that result from pathogen-host interactions. Here, we review potential interactions of the coronavirus and host cellular responses in relation to hallmarks of aging including genomic instability, telomere attrition, impaired autophagy, mitochondrial dysfunction, innate immunosenescence, inflammation and inflammasomes, adaptive immunosenescence, and epigenetic alterations, that likely contribute to the increased pathophysiological responses to SARS-CoV-2 among older adults.

scholarly journals The Central Role of Redox-Regulated Switch Proteins in Bacteria

2021 ◽  
Vol 8 ◽  
Author(s):  
Rosi Fassler ◽  
Lisa Zuily ◽  
Nora Lahrach ◽  
Marianne Ilbert ◽  
Dana Reichmann
Keyword(s):  
Oxidative Stress ◽  
Defense Mechanisms ◽  
Stress Conditions ◽  
New Members ◽  
Post Translational Modifications ◽  
Metal Centers ◽  
Expression Of Genes ◽  
Future Challenges ◽  
Redox Switches

Bacteria possess the ability to adapt to changing environments. To enable this, cells use reversible post-translational modifications on key proteins to modulate their behavior, metabolism, defense mechanisms and adaptation of bacteria to stress. In this review, we focus on bacterial protein switches that are activated during exposure to oxidative stress. Such protein switches are triggered by either exogenous reactive oxygen species (ROS) or endogenous ROS generated as by-products of the aerobic lifestyle. Both thiol switches and metal centers have been shown to be the primary targets of ROS. Cells take advantage of such reactivity to use these reactive sites as redox sensors to detect and combat oxidative stress conditions. This in turn may induce expression of genes involved in antioxidant strategies and thus protect the proteome against stress conditions. We further describe the well-characterized mechanism of selected proteins that are regulated by redox switches. We highlight the diversity of mechanisms and functions (as well as common features) across different switches, while also presenting integrative methodologies used in discovering new members of this family. Finally, we point to future challenges in this field, both in uncovering new types of switches, as well as defining novel additional functions.

scholarly journals Diversity, taxonomy, and evolution of archaeal viruses of the class Caudoviricetes

PLoS Biology ◽  
2021 ◽  
Vol 19 (11) ◽  
pp. e3001442
Author(s):  
Ying Liu ◽  
Tatiana A. Demina ◽  
Simon Roux ◽  
Pakorn Aiewsakun ◽  
Darius Kazlauskas ◽  
...  
Keyword(s):  
Host Range ◽  
Defense Mechanisms ◽  
Halophilic Archaea ◽  
Ecological Impacts ◽  
Tail Fiber ◽  
Range Analysis ◽  
Host Interactions ◽  
Double Stranded Dna ◽  
Anoxic Environments ◽  
Archaeal Viruses

The archaeal tailed viruses (arTV), evolutionarily related to tailed double-stranded DNA (dsDNA) bacteriophages of the class Caudoviricetes, represent the most common isolates infecting halophilic archaea. Only a handful of these viruses have been genomically characterized, limiting our appreciation of their ecological impacts and evolution. Here, we present 37 new genomes of haloarchaeal tailed virus isolates, more than doubling the current number of sequenced arTVs. Analysis of all 63 available complete genomes of arTVs, which we propose to classify into 14 new families and 3 orders, suggests ancient divergence of archaeal and bacterial tailed viruses and points to an extensive sharing of genes involved in DNA metabolism and counter defense mechanisms, illuminating common strategies of virus–host interactions with tailed bacteriophages. Coupling of the comparative genomics with the host range analysis on a broad panel of haloarchaeal species uncovered 4 distinct groups of viral tail fiber adhesins controlling the host range expansion. The survey of metagenomes using viral hallmark genes suggests that the global architecture of the arTV community is shaped through recurrent transfers between different biomes, including hypersaline, marine, and anoxic environments.

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