Vaccines against polio, measles, chickenpox, etc. These, when introduced into a healthy individual, help the immune system to recognize and build immunity to the virus. The body remembers the organism and attacks it in the event of a subsequent infection, thus avoiding disease. Conventional chemotherapy or molecular target therapies have been used to treat virus-associated cancers. Effective immunization or vaccination campaigns for the prevention of these viral infections have led to a remarkable reduction in the cancers caused by these infections.
Different Antiviral therapies have yielded promising results in cancer prevention and treatment. Genetic engineering and modification methods can be used to make modified genomes that can be transported to plants and animals by viruses that act as vectors or vehicles. This method can lead to more productive transgenic animals and plants. Scientists have successfully induced different genes like herbicide tolerance, high nitrogen fixation, high lysine in corn , increased resistance to pests and diseases, in plants by using a virus as a gene carrier and vector.
In an experiment, it was found that all virus -infected plants were much more drought tolerant. After a few years, other researchers discovered that the plant was colonized by a fungus. I was always a little disturbed at the bad rap they get, so it was very exciting for me to find good ones.
Materials provided by American Society for Microbiology. Note: Content may be edited for style and length. Science News. Journal Reference : Marilyn J. Move over bacteria! Viruses make their mark as mutualistic microbial symbionts. Journal of Virology , ; JVI. ScienceDaily, 30 April American Society for Microbiology. Viruses: You've heard the bad; here's the good. At the same time, the presence of persistent viral genotypes throughout the study period suggested co-existence between specific viruses and their hosts.
Understanding of the environmental drivers of virus-host interaction is essential for predicting how environmental changes will affect virus-driven processes in a future ocean [ 19 ].
Highfield et al. Maat et al. As the predicted warming of the Arctic regions will stimulate Micromonas growth rates and promote growth earlier in the season, the authors suggest that viral production will likely do the same.
The increased accumulation of viral metagenomic data the past decade has revealed a huge viral diversity e. Even at very small scales, viral diversity may be high, as demonstrated by Flaviani et al.
The large number of unknown viral populations in the marine metagenome emphasizes the need for further isolation, characterization and sequencing of specific marine viruses.
This special issue presents several new marine viruses of eukaryotes Prymnesium parvum , [ 26 ] and bacteria Shewanella , [ 27 ], Vibrio anguillarum [ 28 ] and Dinoroseobacter shibae [ 29 ] , adding to the rapidly growing database of genome-sequenced and characterized marine viruses.
Several auxiliary metabolic genes and other functional genes were identified in the phage genomes, suggesting a mutual benefit for both phage and host that could potentially be disseminated to other hosts by horizontal gene transfer Figure 1. Prophage-encode genes can thus contribute to host functional properties, including virulence, by so-called lysogenic conversion, potentially expanding the niches occupied by the lysogenized hosts Figure 1.
Further, prophage induction can stimulate biofilm formation by promoting the release of extracellular DNA, which becomes a component in the biofilm matrix [ 30 ]. The paper by Leigh et al. Shewanella is part of a complex relationship between the C. Viruses may also acquire accessory genes from their eukaryotic or prokaryotic hosts [ 31 ] Figure 1. By expressing these genes during infection, the viruses may augment key steps in cellular metabolism and ultimately increase virus production [ 32 ].
In addition to using viral genes acquired from the host, viruses may also control the expression of host genes during infection to promote viral production or inhibit host defense systems.
The high local viral diversity obtained from oceanic metagenomic data [ 22 ] suggests a high dispersal of viral genes across the sampled ocean viral communities. Moebus [ 4 ] had already demonstrated that bacterial viruses with specific infectious properties were distributed across large spatial scales in the North Atlantic.
Later, a worldwide distribution of a virus infecting the picophytoplankton Micromonas pusilla was reported by Cottrell and Suttle [ 34 ], suggesting that viruses are efficiently spread in the marine environment.
This is supported by the study by Kalatzis et al. The authors argue that selection for co-existence, rather than arms race dynamics, might explain the global distribution of near-identical Hlike bacteriophages and their prevalence as prophages in Vibrio genomes. Viral host cells have developed multiple defense strategies against lytic viral infections Figure 1. These include both mutational changes in the cell surface receptors providing resistance to phage adsorption, and various mechanisms for destroying the viral DNA upon infection e.
Mordecai et al. Defense strategies are often associated with a fitness cost, as surface modification mutations may have an influence on, e. Such trade-offs between resistance and fitness costs were explored in the two groups of eukaryotic phytoplankton, Ostreococcus tauri [ 39 ], and E.
Surprisingly, no direct cost of resistance was detected in these systems, emphasizing the complexity of interplay between virus-host co-evolution and the environmental conditions. The large and diverse group of nucleocytoplasmic large DNA viruses NCLDV includes a number of viral families infecting small photosynthetic protists, thus affecting mortality, evolution and production of these phytoplankton. In the current special issue, the research on NCLDV infecting phytoplankton is represented by the Prasinoviruses infecting the ubiquitous group of pico-sized Prasinophycea such as Micromonas and Ostreococcus [ 21 , 39 , 41 ], and viruses infecting bloom-forming haptophytes such as Prymnesium parvum [ 18 , 26 ] and Emiliania huxleyi [ 20 , 31 , 36 , 40 ].
These studies highlight the progression in our understanding of the role of viruses infecting eukaryotic algae, provide a synthesis of the current knowledge in the field, and identify gaps in our knowledge surrounding viral life history and interactions with their hosts.
The discovery of the giant Acanthamoeba polyphaga mimivirus stimulated a new line of research, exploring the ecology and evolution of the group of large DNA viruses infecting eukaryotic protists, including the haptophyte Phaeocystis globosa [ 42 ].
Here, Wilhelm et al. The compilation of papers included in the current special issue highlights the exploration of eukaryotic and prokaryotic viruses, from discovery to complex interplays between virus and host and the interactions with ecologically relevant environmental variables.
The discovery of novel viruses and new mechanisms underlying virus distribution and diversity exemplify the fascinating world of marine viruses. In a time where life in the oceans is under increasing threat global warming, acidification, pollution, economic use , it is pressing to understand how viruses affect host population dynamics, biodiversity, biogeochemical cycling and ecosystem efficiency.
National Center for Biotechnology Information , U. They also say reductions in pollution and emissions should be done without ruining economies. Increases in smog in countries that usually experience it have been down because of lockdowns.
New data shows strong reductions in nitrogen dioxide concentrations over several major cities across Europe, including Paris, Madrid and Rome. Nitrogen dioxide is a by-product of burning fossil fuels that causes respiratory problems.
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