scholarly journals A filamentous archaeal virus is enveloped inside the cell and released through pyramidal portals

2021 ◽  
Vol 118 (32) ◽  
pp. e2105540118
Author(s):  
Diana P. Baquero ◽  
Anastasia D. Gazi ◽  
Martin Sachse ◽  
Junfeng Liu ◽  
Christine Schmitt ◽  
...  
Keyword(s):  
Life Cycle ◽  
Electron Tomography ◽  
Hexagonal Lattice ◽  
Hyperthermophilic Archaea ◽  
Cell Diameter ◽  
Archaeal Virus ◽  
Host Interactions ◽  
Host Interaction ◽  
Sulfolobus Islandicus ◽  
Multiple Copies

The majority of viruses infecting hyperthermophilic archaea display unique virion architectures and are evolutionarily unrelated to viruses of bacteria and eukaryotes. The lack of relationships to other known viruses suggests that the mechanisms of virus–host interaction in Archaea are also likely to be distinct. To gain insights into archaeal virus–host interactions, we studied the life cycle of the enveloped, ∼2-μm-long Sulfolobus islandicus filamentous virus (SIFV), a member of the family Lipothrixviridae infecting a hyperthermophilic and acidophilic archaeon Saccharolobus islandicus LAL14/1. Using dual-axis electron tomography and convolutional neural network analysis, we characterize the life cycle of SIFV and show that the virions, which are nearly two times longer than the host cell diameter, are assembled in the cell cytoplasm, forming twisted virion bundles organized on a nonperfect hexagonal lattice. Remarkably, our results indicate that envelopment of the helical nucleocapsids takes place inside the cell rather than by budding as in the case of most other known enveloped viruses. The mature virions are released from the cell through large (up to 220 nm in diameter), six-sided pyramidal portals, which are built from multiple copies of a single 89-amino-acid-long viral protein gp43. The overexpression of this protein in Escherichia coli leads to pyramid formation in the bacterial membrane. Collectively, our results provide insights into the assembly and release of enveloped filamentous viruses and illuminate the evolution of virus–host interactions in Archaea.

Exploitation of plant and archaeal viruses in bionanotechnology

2009 ◽  
Vol 37 (4) ◽  
pp. 665-670 ◽  
Author(s):  
David J. Evans
Keyword(s):  
The Body ◽  
Layer By Layer ◽  
Archaeal Virus ◽  
Sulfolobus Islandicus ◽  
Naturally Occurring ◽  
Archaeal Viruses ◽  
Nanobuilding Blocks ◽  
Multiple Copies ◽  
Site Selective ◽  
Virion Surface

CPMV (cowpea mosaic virus), a plant virus, is a naturally occurring sphere-like nanoparticle, and is used as a synthon and/or template in bionanoscience. The virions formed by CPMV can be regarded as programmable nanobuilding blocks with a diameter of ∼30 nm. A range of molecules have been attached to this viral nanoscaffold, yielding stable nanoparticles that display multiple copies of the desired molecule. It has been shown that, in addition to surface amine groups, surface carboxy groups are also addressable, and a procedure has been developed that enables introduction of reactive thiols at the virion surface that avoids virus aggregation. Furthermore, the virions can be functionalized to form electroactive nanoparticles. Methods for the construction of arrays and multilayers, using a layer-by-layer approach, have been established. As proof of concept, for example, CPMV particles have been immobilized on surfaces and arranged in defined layers. Engineered variants of CPMV can be used as templates for mineralization with, for example, silica to give monodisperse robust silica nanoparticles of ∼32 nm. SIRV2 (Sulfolobus islandicus rod-shaped virus 2), is a robust archaeal virus, resistant to high temperature and low pH. SIRV2 can act as a template for site-selective and spatially controlled chemical modification. Both the ends and the body of the virus, or the ends only, can be chemically addressed; SIRV2 can be regarded as a structurally unique nanobuilding block.

scholarly journals Genomics and biology of Rudiviruses, a model for the study of virus–host interactions in Archaea

2013 ◽  
Vol 41 (1) ◽  
pp. 443-450 ◽  
Author(s):  
David Prangishvili ◽  
Eugene V. Koonin ◽  
Mart Krupovic
Keyword(s):  
Current Knowledge ◽  
Model System ◽  
Model Systems ◽  
Hyperthermophilic Archaea ◽  
Future Studies ◽  
Host Interactions ◽  
Sulfolobus Islandicus ◽  
Virus Life Cycle ◽  
Archaeal Viruses ◽  
Global Understanding

Archaeal viruses, especially viruses that infect hyperthermophilic archaea of the phylum Crenarchaeota, constitute one of the least understood parts of the virosphere. However, owing to recent substantial research efforts by several groups, archaeal viruses are starting to gradually reveal their secrets. In the present review, we summarize the current knowledge on one of the emerging model systems for studies on crenarchaeal viruses, the Rudiviridae. We discuss the recent advances towards understanding the function and structure of the proteins encoded by the rudivirus genomes, their role in the virus life cycle, and outline the directions for further research on this model system. In addition, a revised genome annotation of SIRV2 (Sulfolobus islandicus rod-shaped virus 2) is presented. Future studies on archaeal viruses, combined with the knowledge on viruses of bacteria and eukaryotes, should lead to a better global understanding of the diversity and evolution of virus–host interactions in the viral world.

scholarly journals Global transcriptome landscape of the rabbit protozoan parasite Eimeria stiedae

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Yue Xie ◽  
Jie Xiao ◽  
Xuan Zhou ◽  
Xiaobin Gu ◽  
Ran He ◽  
...  
Keyword(s):  
Life Cycle ◽  
Single Molecule ◽  
Average Length ◽  
Expression Patterns ◽  
Protozoan Parasite ◽  
Host Interactions ◽  
Host Interaction ◽  
Life Cycle Stages ◽  
Global Transcriptome ◽  
Eimeria Stiedae

Abstract Background Coccidiosis caused by Eimeria stiedae is a widespread and economically significant disease of rabbits. The lack of studies on the life-cycle development and host interactions of E. stiedae at the molecular level has hampered our understanding of its pathogenesis. Methods In this study, we present a comprehensive transcriptome landscape of E. stiedae to illustrate its dynamic development from unsporulated oocysts to sporulated oocysts, merozoites, and gametocytes, and to identify genes related to parasite-host interactions during parasitism using combined PacBio single-molecule real-time and Illumina RNA sequencing followed by bioinformatics analysis and qRT-PCR validation. Results In total, 12,582 non-redundant full-length transcripts were generated with an average length of 1808 bp from the life-cycle stages of E. stiedae. Pairwise comparisons between stages revealed 8775 differentially expressed genes (DEGs) showing highly significant description changes, which compiled a snapshot of the mechanisms underlining asexual and sexual biology of E. stiedae including oocyst sporulation between unsporulated and sporulated oocysts; merozoite replication between sporulated oocysts and merozoites; and gametophyte development and gamete generation between merozoites and gametocytes. Further, 248 DEGs were grouped into nine series clusters and five groups by expression patterns, and showed that parasite–host interaction-related genes predominated in merozoites and gametocytes and were mostly involved in steroid biosynthesis and lipid metabolism and carboxylic acid. Additionally, co-expression analyses identified genes associated with development and host invasion in unsporulated and sporulated oocysts and immune interactions during gametocyte parasitism. Conclusions This is the first study, to our knowledge, to use the global transcriptome profiles to decipher molecular changes across the E. stiedae life cycle, and these results not only provide important information for the molecular characterization of E. stiedae, but also offer valuable resources to study other apicomplexan parasites with veterinary and public significance. Graphic Abstract

scholarly journals Is 20S RNA naked?

1991 ◽  
Vol 11 (5) ◽  
pp. 2905-2908 ◽  
Author(s):  
W R Widner ◽  
Y Matsumoto ◽  
R B Wickner
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Life Cycle ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Rna Virus ◽  
Circular Rna ◽  
Ribonucleoprotein Particle ◽  
Multiple Copies

The 20S RNA of Saccharomyces cerevisiae is a single-stranded, circular RNA virus. A previous study suggested that this RNA is part of a 32S ribonucleoprotein particle, being associated with multiple copies of a 23-kilodalton protein. We show here that this protein is, in fact, the chromosome-encoded heat shock protein Hsp26. Furthermore, it is apparently not associated with 20S RNA and plays no obvious role in the life cycle of the virus.

scholarly journals Apicortin, a Constituent of Apicomplexan Conoid/Apical Complex and Its Tentative Role in Pathogen—Host Interaction

2021 ◽  
Vol 6 (3) ◽  
pp. 118
Author(s):  
Ferenc Orosz
Keyword(s):  
Plasmodium Falciparum ◽  
Toxoplasma Gondii ◽  
Therapeutic Target ◽  
In Silico ◽  
Free Living ◽  
Binding Properties ◽  
Host Interactions ◽  
Trichoplax Adhaerens ◽  
Host Interaction ◽  
Apical Complex

In 2009, apicortin was identified in silico as a characteristic protein of apicomplexans that also occurs in the placozoa, Trichoplax adhaerens. Since then, it has been found that apicortin also occurs in free-living cousins of apicomplexans (chromerids) and in flagellated fungi. It contains a partial p25-α domain and a doublecortin (DCX) domain, both of which have tubulin/microtubule binding properties. Apicortin has been studied experimentally in two very important apicomplexan pathogens, Toxoplasma gondii and Plasmodium falciparum. It is localized in the apical complex in both parasites. In T. gondii, apicortin plays a key role in shaping the structure of a special tubulin polymer, conoid. In both parasites, its absence or downregulation has been shown to impair pathogen–host interactions. Based on these facts, it has been suggested as a therapeutic target for treatment of malaria and toxoplasmosis.

scholarly journals Protein Tyrosine and Serine/Threonine Phosphorylation in Oral Bacterial Dysbiosis and Bacteria-Host Interaction

2022 ◽  
Vol 11 ◽  
Author(s):  
Liang Ren ◽  
Daonan Shen ◽  
Chengcheng Liu ◽  
Yi Ding
Keyword(s):  
Community Development ◽  
Oral Bacteria ◽  
Bacterial Metabolism ◽  
Oral Microbiota ◽  
Bacterial Protein ◽  
Oral Diseases ◽  
Host Interactions ◽  
Host Interaction ◽  
Systemic Health

The human oral cavity harbors approximately 1,000 microbial species, and dysbiosis of the microflora and imbalanced microbiota-host interactions drive many oral diseases, such as dental caries and periodontal disease. Oral microbiota homeostasis is critical for systemic health. Over the last two decades, bacterial protein phosphorylation systems have been extensively studied, providing mounting evidence of the pivotal role of tyrosine and serine/threonine phosphorylation in oral bacterial dysbiosis and bacteria-host interactions. Ongoing investigations aim to discover novel kinases and phosphatases and to understand the mechanism by which these phosphorylation events regulate the pathogenicity of oral bacteria. Here, we summarize the structures of bacterial tyrosine and serine/threonine kinases and phosphatases and discuss the roles of tyrosine and serine/threonine phosphorylation systems in Porphyromonas gingivalis and Streptococcus mutans, emphasizing their involvement in bacterial metabolism and virulence, community development, and bacteria-host interactions.

scholarly journals Sixth European Seminar in Virology on Virus–Host Interaction at Single Cell and Organism Level

Viruses ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 400
Author(s):  
Elisa Saccon ◽  
Adriana Vitiello ◽  
Marta Trevisan ◽  
Cristiano Salata ◽  
Giorgio Palù
Keyword(s):  
Immune Response ◽  
Single Cell ◽  
Virus Evolution ◽  
Cell Level ◽  
Host Interactions ◽  
Host Interaction ◽  
Young Researchers

The 6th European Seminar in Virology (EuSeV) was held in Bertinoro, Italy, 22–24 June 2018, and brought together international scientists and young researchers working in the field of Virology. Sessions of the meeting included: virus–host-interactions at organism and cell level; virus evolution and dynamics; regulation; immunity/immune response; and disease and therapy. This report summarizes lectures by the invited speakers and highlights advances in the field.

scholarly journals Acquisition of intact polar lipids from the prymnesiophyte <i>Phaeocystis globosa</i> by its lytic virus PgV-07T

2014 ◽  
Vol 11 (1) ◽  
pp. 185-194 ◽  
Author(s):  
D. S. Maat ◽  
N. J. Bale ◽  
E. C. Hopmans ◽  
A.-C. Baudoux ◽  
J. S. Sinninghe Damsté ◽  
...  
Keyword(s):  
Viral Infection ◽  
Lower Proportion ◽  
Specific Lipids ◽  
Phaeocystis Globosa ◽  
Host Interactions ◽  
Algal Virus ◽  
Host Interaction ◽  
Betaine Lipids ◽  
Algal Host ◽  
Intact Polar Lipids

Abstract. Recent studies showed changes in phytoplankton lipid composition during viral infection and have indicated roles for specific lipids in the mechanisms of algal virus-host interaction. To investigate the generality of these findings and obtain a better understanding of the allocation of specific lipids to viruses, we studied the intact polar lipid (IPL) composition of virally infected and non-infected cultures of the prymnesiophyte Phaeocystis globosa G(A) and its lytic virus PgV-07T. The P. globosa IPL composition was relatively stable over a diel cycle and not strongly affected by viral infection. Glycolipids, phospholipids and betaine lipids were present in both the host and virus, although specific groups such as the diacylglyceryl-hydroxymethyltrimethyl-β-alanines and the sulfoquinovosyldiacylglycerols, were present in a lower proportion or were not detected in the virus. Viral glycosphingolipids (vGSLs), which have been shown to play a role in the infection strategy of the virus EhV-86, infecting the prymnesiophyte Emiliania huxleyi CCMP374, were not encountered. Our results show that the involvement of lipids in virus–algal host interactions can be very different amongst virus–algal host systems.

scholarly journals ORF4 of the Temperate Archaeal Virus SNJ1 Governs the Lysis-Lysogeny Switch and Superinfection Immunity

2020 ◽  
Vol 94 (16) ◽  
Author(s):  
Beibei Chen ◽  
Zhao Chen ◽  
Yuchen Wang ◽  
Han Gong ◽  
Linshan Sima ◽  
...  
Keyword(s):  
Life Cycle ◽  
Bioinformatic Analysis ◽  
Model System ◽  
Life Cycles ◽  
Host Cells ◽  
Biological Functions ◽  
Mechanistic Studies ◽  
Cultivation Conditions ◽  
Archaeal Virus ◽  
Archaeal Viruses

ABSTRACT Recent environmental and metagenomic studies have considerably increased the repertoire of archaeal viruses and suggested that they play important roles in nutrient cycling in the biosphere. However, very little is known about how they regulate their life cycles and interact with their hosts. Here, we report that the life cycle of the temperate haloarchaeal virus SNJ1 is controlled by the product ORF4, a small protein belonging to the antitoxin MazE superfamily. We show that ORF4 controls the lysis-lysogeny switch of SNJ1 and mediates superinfection immunity by repression of genomic DNA replication of the superinfecting viruses. Bioinformatic analysis shows that ORF4 is highly conserved in two SNJ1-like proviruses, suggesting that the mechanisms for lysis-lysogeny switch and superinfection immunity are conserved in this group of viruses. As the lysis-lysogeny switch and superinfection immunity of archaeal viruses have been poorly studied, we suggest that SNJ1 could serve as a model system to study these processes. IMPORTANCE Archaeal viruses are important parts of the virosphere. Understanding how they regulate their life cycles and interact with host cells provide crucial insights into their biological functions and the evolutionary histories of viruses. However, mechanistic studies of the life cycle of archaeal viruses are scarce due to a lack of genetic tools and demanding cultivation conditions. Here, we discover that the temperate haloarchaeal virus SNJ1, which infects Natrinema sp. strain J7, employs a lysis-lysogeny switch and establishes superinfection immunity like bacteriophages. We show that its ORF4 is critical for both processes and acts as a repressor of the replication of SNJ1. These results establish ORF4 as a master regulator of SNJ1 life cycle and provides novel insights on the regulation of life cycles by temperate archaeal viruses and on their interactions with host cells.

Apoptosis and autophagy as a turning point in viral–host interactions: the case of human norovirus and its surrogates

2020 ◽  
Author(s):  
Sean Kennedy ◽  
Mélanie M Leroux ◽  
Alexis Simons ◽  
Brice Malve ◽  
Marc Devocelle ◽  
...  
Keyword(s):  
Viral Entry ◽  
Turning Point ◽  
Infection Process ◽  
Host Interactions ◽  
Antiviral Therapies ◽  
Leading Role ◽  
Host Interaction ◽  
Major Response ◽  
Causes Of Disease ◽  
Viral Host Interactions

Human gastroenteritis viruses are amid the major causes of disease worldwide, responsible for more than 2 million deaths per year. Human noroviruses play a leading role in the gastroenteritis outbreaks and the continuous emergence of new strains contributes to the significant morbidity and mortality. Many aspects of the viral entry and infection process remain unclear, including the major response of the host cell to the virus, which is the trigger of several programmed cell death related mechanisms. In this review, we assessed apoptosis and autophagy at various stages in the infection process to provide better understanding of the viral–host interaction. This brings us closer to fully understanding how noroviruses work, thus allowing the development of specific antiviral therapies.

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