Name: archaeal virus shapes and extreme survival
Uploaded: 2025-06-12T09:30:13.000Z
Duration: 1 min 29 s
Channel: JoVE

K12 Standards

Virginia  Standards of Learning

HIgh School

Biology

BIO.4

BIO.4.a

Viruses of Archaea

Archaeal viruses infect extremophilic archaea, specifically Euryarchaeota and Crenarchaeota species.Most archaeal viruses have double-stranded DNA genomes, though some carry single-stranded DNA or RNA.One such virus, the Sulfolobus spindle-shaped virus or SSV, has a circular double-stranded DNA genome of about 15 kilobases.SSV produces spindle-shaped virions &#8212; complete virus particles &#8212; that cluster into rosettes.Similarly, the Sulfolobus filamentous virus has a rigid, rod-shaped structure and a linear double-stranded DNA genome.The Acidianus two-tailed virus initially forms a lemon-shaped particle but develops two long, thin tails shortly after being released from the host cell.Another virus, PAV1, possesses a circular DNA genome. It infects Pyrococcus species and is released from the host via budding.PAV1 virions remain stable at 100&#176;C, making them highly heat-resistant.Recent metagenomic studies postulate the existence of RNA archaeal viruses in acidic hot springs, although none have been isolated or cultured so far.

viruses of archaea

Archaeal viruses play a crucial role in the ecosystems of extremophilic archaea, particularly those belonging to the phyla Euryarchaeota and Crenarchaeota. By shaping host evolution and facilitating gene transfer, these viruses influence microbial communities and contribute to genetic diversity in extreme environments. The archaea they infect thrive in acidic hot springs and hydrothermal vents characterized by high temperatures and low pH. Archaeal viruses exhibit remarkable structural diversity and genetic adaptations that enable their survival and propagation in these extreme settings.<h3>Genetic Composition and Virion Structures</h3>Most archaeal viruses possess double-stranded DNA (dsDNA) genomes, though some have single-stranded DNA (ssDNA) or RNA genomes. A well-studied example is the Sulfolobus spindle-shaped virus (SSV), which carries a circular genome of approximately 15 kilobases. Its spindle-shaped virions cluster into rosette-like formations, which enhance stability in its environment&#8217;s harsh thermal and acidic conditions. Another virus, the Sulfolobus filamentous virus, features a rigid, rod-shaped virion structure and a linear DNA genome, further illustrating the diversity in archaeal viral morphologies.<h3>Unique Morphological Adaptations</h3>In addition to spindle and filamentous forms, the Acidianus two-tailed virus (ATV) exhibits a unique morphological transformation. Initially appearing as a lemon-shaped particle, ATV develops long tails after assembly&#8212;a process influenced by temperature and pH shifts rather than direct host interactions. This structural modification is hypothesized to facilitate viral transmission and stability within extreme environments.Another archaeal virus, PAV1, infects Pyrococcus species, a genus of Euryarchaeota adapted to hyperthermophilic environments. PAV1 carries a small circular DNA genome and exits its host via budding, a relatively rare release mechanism among archaeal viruses, which are more commonly released through lysis. Its virions can remain stable at 100&#176;C for extended periods, highlighting their exceptional thermal resistance.<h3>The Emergence of RNA Archaeal Viruses</h3>While most known archaeal viruses are DNA-based, recent research indicates the presence of RNA viruses in acidic hot springs. Although none have been successfully cultured, metagenomic analyses strongly suggest their presence. However, their specific hosts and ecological roles remain largely unknown.For example, metagenomic studies conducted in geothermal hot springs&#8212;such as those in Yellowstone National Park and Kamchatka, Russia&#8212;have uncovered RNA viral sequences associated with hyperthermophilic archaea. These RNA viruses exhibit unique genome structures and replication strategies distinct from known viral families, suggesting evolutionary divergence adapted to extreme conditions.Another study in the hot springs of Iceland identified RNA viruses encoding RNA-dependent RNA polymerase (RdRp), a key enzyme for RNA virus replication. These findings suggest a previously unrecognized evolutionary link between RNA viruses in extreme environments and their potential role in horizontal gene transfer among archaea. However, some RNA viruses identified in metagenomic studies may not directly infect archaea but instead associate with archaeal-dominated microbial communities.

Archaeal viruses play a crucial role in the ecosystems of extremophilic archaea, particularly those belonging to the phyla Euryarchaeota and ...

Education

JoVE Core

Microbiology

Unit

Viruses

KEY TERMS AND CONCEPTS

archaeal virus shapes and extreme survival

Archaeal viruses infect archaea that live in extreme places such as acidic hot springs and hydrothermal vents. These hosts often belong to the phyla Euryarchaeota and Crenarchaeota. The viruses help shape host evolution and gene transfer, which adds genetic diversity to microbial communities in harsh environments.

Most archaeal viruses carry double-stranded DNA, or dsDNA, genomes. Some have single-stranded DNA, and some have RNA genomes. Their virions, or complete virus particles, show unusual shapes and strong adaptations that help them survive heat and acid.

One well-studied example is the Sulfolobus spindle-shaped virus, or SSV. It has a circular genome of about 15 kilobases and spindle-shaped virions that can cluster into rosette-like forms. Another example is the Sulfolobus filamentous virus, which has a rigid, rod-shaped virion and a linear DNA genome.

Some archaeal viruses change shape in special ways. The Acidianus two-tailed virus, or ATV, first appears as a lemon-shaped particle and later develops long tails after assembly. This change is driven by shifts in temperature and pH, not by direct host interaction. Researchers think the tail shape may help with transmission and stability in extreme settings.

PAV1 infects Pyrococcus species, which are Euryarchaeota adapted to very high temperatures. It has a small circular DNA genome and leaves its host by budding, which is less common than lysis in archaeal viruses. Its virions can stay stable at 100°C for long periods, showing strong heat resistance.

Most known archaeal viruses are DNA-based, but RNA viruses have also been detected in acidic hot springs. None have been cultured yet, and their hosts and ecological roles are still unclear. Metagenomic studies in Yellowstone National Park, Kamchatka in Russia, and hot springs in Iceland found RNA viral sequences, including viruses that encode RNA-dependent RNA polymerase, or RdRp. These findings suggest a possible new group of RNA viruses adapted to extreme environments, although some may belong to archaeal-dominated microbial communities rather than infect archaea directly.

Archaeal Virus Shapes and Extreme Survival

archaeal-virus-shapes-and-extreme-survival

introduction to virus

Virus Structure, Entry, and Replication

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size and structure of viral genomes

How Viral Genomes Replicate

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viral replication: lytic cycle

T4 Phage Infection of E. coli

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viral replication: lysogenic cycle

Prophage Integration in Bacterial Cells

The lysogenic cycle shows how a bacteriophage can stay inside a bacterial cell without killing it right away. Temperate phages, such as bacteriophage lambda (λ), use this strategy to persist in Escherichia coli while the host cell remains alive. After attachment to the bacterial surface, the phage injects its genetic material into the cytoplasm. The linear phage genome then circularizes, which helps protect it from host nucleases. Next, phage-encoded integrase carries out recombination that...

dna bacteriophages

How DNA Phages Replicate in Bacteria

DNA bacteriophages are viruses that infect bacteria and use bacterial cell machinery to make more copies of themselves. They carry either single-stranded DNA (ssDNA) or double-stranded DNA (dsDNA), and each group uses a different replication strategy. Their life cycles also shape how they interact with hosts and how scientists use them in biotechnology and medicine. Some ssDNA phages keep their genomes very small and compact. The icosahedral phage ΦX174 shows this clearly because it uses...

Archaeal viruses infect archaea that live in extreme places such as acidic hot springs and hydrothermal vents. These hosts often belong to the phyla Euryarchaeota and Crenarchaeota. The viruses help shape host evolution and gene transfer, which adds genetic diversity to microbial communities in harsh environments. Most archaeal viruses carry double-stranded DNA, or dsDNA, genomes. Some have single-stranded DNA, and some have RNA genomes. Their virions, or complete virus particles, show unusual...

viruses with rna genomes

RNA Virus Replication Strategies

RNA viruses use several replication strategies based on their genome type. They are grouped as positive-strand, negative-strand, or double-stranded RNA viruses. Some RNA viruses also use reverse transcription, which adds another layer to how they copy their genetic material. Positive-strand RNA viruses have genomes that can act like messenger RNA, or mRNA, as soon as they enter a cell. This lets the virus begin making proteins right away. Bacteriophage MS2 infects Escherichia coli by attaching...

the antiviral system of bacteria and archaea: crispr

the-antiviral-system-of-bacteria-and-archaea-crispr

How CRISPR Remembers Viral Infections

CRISPR is an adaptive immune system in bacteria and archaea that helps protect cells from viral infection. It works by identifying foreign genetic material, remembering it, and stopping the same invader later. In many cases, the main targets are bacteriophages, which are viruses that infect bacteria. The first defense step begins during an initial infection. Cas proteins, which are CRISPR-associated proteins, detect foreign DNA by looking for specific sequences called Protospacer Adjacent...

crispr/cas9 genome editing

CRISPR-Cas9 and DNA Repair in Cells

CRISPR-Cas9 uses a bacterial defense system to change DNA in cells. The CRISPR-Cas system first evolved in prokaryotes to protect bacteria from invading genetic material such as viruses and plasmids. Scientists later adapted it into a genome-editing tool for plants, animals, and humans. The key enzyme is Cas9, a DNA-cutting protein called an endonuclease from Streptococcus pyogenes. In the lab, a synthetic single guide RNA, or sgRNA, directs Cas9 to a chosen DNA site. The sgRNA matches the...

subviral agents

Viroids, Prions, and Satellite Viruses

Viroids, prions, and satellites are subviral agents that can cause infection even though they are not complete viruses. They resemble viruses in spread and disease, but each lacks one or more key viral parts, such as a capsid or the machinery needed for replication. Viroids are the simplest of these agents. They are circular, single-stranded RNA molecules with no protein coat. Viroids infect plants only and depend on host cell machinery to copy themselves. Host RNA polymerase replicates them...

key terms and concepts

Explore how archaeal viruses survive extreme heat and acid, from spindle-shaped DNA viruses to rare RNA viruses found in hot springs.

Archaeal Virus Shapes and Extreme Survival | JoVE K12

JoVE Core Microbiology provides an engaging introduction to the microbial world and its influence on health, industry, and the environment. This comprehensive collection covers key concepts such as microbial structure, metabolism, genetics, and ecology. It introduces essential laboratory techniques and microscopy methods through visually engaging animations. Corresponding scientist-in-action videos bridge classroom concepts with real-world research and applications.

microbiology

Alabama Course of Study Science

9-12

Unity and Diversity

9-12.B.4.13.a

Introduction to Virus

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Size and Structure of Viral Genomes

Viral genomes exhibit remarkable diversity in size, structure, and composition, influencing their replication strategies and interactions with host cells. ...

Viral Replication: Lytic Cycle

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Viral Replication: Lysogenic Cycle

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DNA Bacteriophages

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Viruses with RNA Genomes

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The Antiviral System of Bacteria and Archaea: CRISPR

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CRISPR/Cas9 Genome Editing

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Subviral Agents

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Bacterial Growth Curve

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microbial-growth-measurement-indirect-methods

Microbial Growth Measurement: Indirect Methods

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Microbial Growth Media

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Need for Obtaining Pure Cultures

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Techniques for Isolation of Pure Cultures

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Factors Influencing Microbial Growth: pH

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factors-influencing-microbial-growth-temperature

Factors Influencing Microbial Growth: Temperature

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BIO.4.b

Prokaryotic vs. Eukaryotic Cells

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Microbial Morphologies 

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Bacterial Cell Wall 

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Endospores and Sporulation

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Nucleoid

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Surface Appendages of Archaea

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BIO.4.c

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Detection of Bacteriophages in Environmental Samples

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Culturing and Enumerating Bacteria from Soil Samples

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bacterial-growth-curve-analysis-and-its-environmental-applications

Bacterial Growth Curve Analysis and its Environmental Applications

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BIO.4.d

History of Microbiology

Microbiology, a scientific field dedicated to the study of microorganisms, has undergone profound development since its inception in the 17th century. Its ...

Infection

When a pathogen enters the body and reproduces, it can cause an infection, damage body cells, and cause illness symptoms that eventually lead to disease. ...

Defense Mechanism Against Infection

Natural flora, body system defenses, and inflammation are natural barriers of the body against infectious agents regardless of previous exposure. Normal ...

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BIO.4.e

Archaeal Virus Shapes and Extreme Survival

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