Miaviricetes

Miaviricetes is a class of viruses within the phylum Uroviricota, which is part of the realm Duplodnaviria. This class is characterized by viruses that possess double-stranded DNA genomes and are known to infect a wide range of hosts, including bacteria and archaea. The class Miaviricetes is notable for its inclusion of the order Caudovirales, which comprises the well-known tailed bacteriophages.

Taxonomy

Miaviricetes is a class within the phylum Uroviricota, which is part of the kingdom Heunggongvirae. The class currently includes the following order:

• Caudovirales

The order Caudovirales is further divided into several families, including Myoviridae, Siphoviridae, and Podoviridae, each distinguished by the morphology of their tails and other structural features.

Characteristics

Viruses in the class Miaviricetes are characterized by their double-stranded DNA genomes. They are known for their complex virion structures, which often include a head-tail morphology. The head, or capsid, contains the viral genome, while the tail is used to attach to and penetrate host cells.

Genome

The genomes of Miaviricetes viruses are typically linear and can vary significantly in size, ranging from tens to hundreds of kilobases. These genomes encode a variety of proteins necessary for the virus's replication and assembly within the host cell.

Morphology

The virions of Miaviricetes are generally composed of an icosahedral capsid and a tail structure. The tail can be long and contractile, as seen in the family Myoviridae, or short and non-contractile, as in the family Podoviridae. The tail structure is crucial for the infection process, as it facilitates the injection of the viral genome into the host cell.

Life Cycle

The life cycle of Miaviricetes viruses typically involves the following stages:

1. Attachment: The virus attaches to the surface of the host cell using its tail fibers. 2. Penetration: The tail contracts (in some families), injecting the viral DNA into the host cell. 3. Replication: The viral genome is replicated using the host's cellular machinery. 4. Assembly: New virions are assembled within the host cell. 5. Release: The host cell is lysed, releasing new virions to infect additional cells.

Importance

Miaviricetes viruses, particularly those in the order Caudovirales, play a significant role in microbial ecology and evolution. They are abundant in various environments, including soil, water, and the human microbiome, where they influence microbial population dynamics and gene transfer.

Also see

• Bacteriophage
• Viral taxonomy
• Duplodnaviria
• Uroviricota