jedzenie: Marine viruses

Evidence: 100 • authority: 72

Marine viruses are defined by their habitat as viruses that are found in marine environments, that is, in the saltwater of seas or oceans or the brackish water of coastal estuaries. Viruses are small infectious agents that can only replicate inside the living cells of a host organism, because they need the replication machinery of the host to do so. They can infect all types of life forms, from animals and plants to microorganisms, including bacteria and archaea. When not inside a cell or in the process of infecting a cell, viruses exist in the form of independent particles called virions. A virion contains a genome (a long molecule that carries genetic information in the form of either DNA…

Evidence: 75 • authority: 72

A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. Since the first discovery of a virus, the tobacco mosaic virus, in the 1890s, more than 16,000 of the millions of virus species have been described in detail. The study of viruses is known as virology, a subspeciality of microbiology. When infected, a host cell is often forced to rapidly produce thousands of copies of the original virus. When not inside an infected cell or in th…

Evidence: 68 • authority: 72

A virus is a tiny infectious agent that reproduces inside the cells of living hosts. When infected, the host cell is forced to rapidly produce thousands of copies of the original virus. Unlike most living things, viruses do not have cells that divide; new viruses assemble in the infected host cell. But unlike simpler infectious agents like prions, they contain genes, which allow them to mutate and evolve. Over 4,800 species of viruses have been described in detail out of the millions in the environment. Their origin is unclear: some may have evolved from plasmids—pieces of DNA that can move between cells—while others may have evolved from bacteria. Viruses are made of either two or three pa…

Evidence: 56 • authority: 92

Viral infection and virophage co-infection induce distinct remodeling of host lipidome. Virophages are small double-stranded DNA viruses that co-infect eukaryotic cells along with giant viruses. They are widespread in aquatic ecosystems and can influence microbial population dynamics by acting as an adaptive antiviral defense system, limiting production of giant virus progeny. Giant viruses extensively reprogram host metabolism to support their replication, yet little is known about how this process is altered by virophages. Characterizing these alterations may reveal the metabolic mechanisms underlying virophage-mediated changes in infection outcomes. Here, we used one of the few establish…

Evidence: 49 • authority: 88

Host-Dependent Modifications of Packaged Alphavirus Genomic RNA Influence Virus Replication in Mammalian Cells. Alphaviruses must interact efficiently with two distinct host environments in order to replicate and transmit between vertebrate and mosquito hosts. Some host-origin-dependent differences in virus particle composition that appear to facilitate the transmission cycle are known. However, the impact of host-mediated modification of packaged viral genomic RNA on subsequent infection has not been previously investigated. Here we show that in human (HEK-293) cells, mosquito-derived Sindbis virus (SINV) replicates and spreads faster, producing a more infectious virus than its mammalian-d…

Evidence: 43 • authority: 88

Viral and Host Factors Required for Avian H5N1 Influenza A Virus Replication in Mammalian Cells. Following the initial and sporadic emergence into humans of highly pathogenic avian H5N1 influenza A viruses in Hong Kong in 1997, we have come to realize the potential for avian influenza A viruses to be transmitted directly from birds to humans. Understanding the basic viral and cellular mechanisms that contribute to infection of mammalian species with avian influenza viruses is essential for developing prevention and control measures against possible future human pandemics. Multiple physical and functional cellular barriers can restrict influenza A virus infection in a new host species, inclu…

Evidence: 43 • authority: 80

THE REPLICATION SCHEMES OF INSECT VIRUSES IN HOST CELLS

Evidence: 37 • authority: 88

Cross-Regulation between Transposable Elements and Host DNA Replication. Transposable elements subvert host cellular functions to ensure their survival. Their interaction with the host DNA replication machinery indicates that selective pressures lead them to develop ancestral and convergent evolutionary adaptations aimed at conserved features of this fundamental process. These interactions can shape the co-evolution of the transposons and their hosts.

Evidence: 37 • authority: 92

Single-cell-resolved frequency and modes of phage interactions with prokaryoplankton in the tropical surface ocean. Marine planktonic viruses play critical roles in shaping microbial communities and driving global biogeochemical cycles. However, quantitative, microbiome-wide analyses of marine prokaryoplankton- virus interactions in situ and their ecological impacts remain challenging due to the vast diversity of viral genomes and interaction modes and the limitations of existing methodologies. Here, we utilized GORG- Tropics, a global collection of 12,715 single amplified genomes (SAGs) generated from randomly sampled marine prokaryoplankton cells, to determine the frequency and modes of t…

Evidence: 37 • authority: 92

Quantifying Viral Lysis in Microalgae Using Cell-Free rRNA.. Viral lysis is a major driver of phytoplankton mortality and a key source of dissolved organic matter in the ocean, yet quantitative and taxon-resolved measurements of this process remain limited for eukaryotic plankton. Here, we demonstrate that cell-free ribosomal RNA (rRNA) dissolved in the extracellular medium serves as a quantitative proxy for viral lysis in microeukaryotes by combining laboratory infection experiments with a rate-based modeling framework. We investigated two host-virus systems: the diatom Chaetoceros tenuissimus infected by a single-stranded RNA virus (CtenRNAV) and the raphidophyte Heterosigma akashiwo infe…

Evidence: 37 • authority: 72

The virus world hypothesis (or the virus-first, the virus early, or the co-evolution hypothesis) proposes that self-replicating virus-like genetic elements existed before cellular life and contributed to its emergence. It is one of several scientific hypotheses that attempt to explain the origin and evolution of viruses. All modern viruses are obligate parasites that cannot replicate independently of their cellular hosts; thus it may seem more intuitive to assume that viruses originated from cells, an idea known as the "escape hypothesis". However, within the framework of an hypothesized "virus world", modern viruses are held to be possible direct descendants of the very first replicons to…

Evidence: 37 • authority: 80

Inside Job: Viruses Transfer cGAMP between Cells