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Topic Review
Viroids: Definition and Features
Viroids are plant-restricted parasites that represent a remarkable model system to analyze many aspects of host-pathogen interactions at the genomic level. As the smallest known agents of infectious disease (247-401 nucleotides, nt), they have a highly structured, single-stranded circular naked and non-coding RNA genome. Although the list of known diseases caused by viroids and molecular characterization of the causative agents has expanded since they were discovered, their origin, evolution, and interaction with host genetic machinery to induce symptoms or escape the defensive system remain unclear.
  • 7.6K
  • 01 Nov 2020
Topic Review
Viroids and Plants
Viroids are plant pathogenic, circular, non-coding, single-stranded RNAs (ssRNAs). Members of the Pospiviroidae family replicate in the nucleus of plant cells through double-stranded RNA (dsRNA) intermediates, thus triggering the host’s RNA interference (RNAi) machinery. In plants, the two RNAi pillars are Post-Transcriptional Gene Silencing (PTGS) and RNA-directed DNA Methylation (RdDM), and the latter has the potential to trigger Transcriptional Gene Silencing (TGS). Over the last three decades, the employment of viroid-based systems has immensely contributed to our understanding of both of these RNAi facets.
  • 1.0K
  • 20 May 2021
Topic Review
Viroids
Viroids are a group of infectious plant lncRNAs that are composed of RNA genomes and replicate by using the host enzymatic activities.
  • 1.9K
  • 30 Oct 2020
Topic Review
Virion Structure of SARS-CoV-2 and Viral Inflammation
COVID-19 is an epidemic infection created by SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2). SARS-CoV-2 has a single-stranded, positive-sense RNA genome with 29,891 nucleotides and 38% G + C content, encoding 9860 amino acids. Human coronaviral inflammation induces the clinical symptoms of fever, cough, and shortness of breath.
  • 545
  • 25 Nov 2022
Topic Review
Virgo Interferometer
The Virgo interferometer is a large interferometer designed to detect gravitational waves predicted by the general theory of relativity. Virgo is a Michelson interferometer that is isolated from external disturbances: its mirrors and instrumentation are suspended and its laser beam operates in a vacuum. The instrument's two arms are three kilometres long and located near Pisa, Italy. Virgo is part of a scientific collaboration of laboratories from six countries: Italy and France (the two countries behind the project), the Netherlands, Poland, Hungary and Spain. Other interferometers similar to Virgo have the same goal of detecting gravitational waves, including the two LIGO interferometers in the United States (at the Hanford Site and in Livingston, Louisiana). Since 2007, Virgo and LIGO have agreed to share and jointly analyze the data recorded by their detectors and to jointly publish their results. Because the interferometric detectors are not directional (they survey the whole sky) and they are looking for signals which are weak, infrequent, one-time events, simultaneous detection of a gravitational wave in multiple instruments is necessary to confirm the signal validity and to deduce the angular direction of its source. The interferometer is named for the Virgo Cluster of about 1,500 galaxies in the Virgo constellation, about 50 million light-years from Earth. As no terrestrial source of gravitational wave is powerful enough to produce a detectable signal, Virgo must observe the Universe. The more sensitive the detector, the further it can see gravitational waves, which then increases the number of potential sources. This is relevant as the violent phenomena Virgo is potentially sensitive to (coalescence of a compact binary system, neutron stars or black holes; supernova explosion; etc.) are rare: the more galaxies Virgo is surveying, the larger the probability of a detection.
  • 552
  • 18 Nov 2022
Topic Review
Virgo
Virgo is one of the 12 constellations of the zodiac, located between Leo to the west and Libra to the east. Covering a vast area of the sky, Virgo is the second-largest constellation after Hydra. Represented as a maiden holding a sheaf of wheat, Virgo is often associated with fertility and agriculture in ancient mythology. This constellation is notable for hosting the bright star Spica, which serves as a celestial marker for navigation and observation.
  • 606
  • 15 Mar 2024
Topic Review
Virgin Olive Oil
Virgin olive oil (VOO) has unique chemical characteristics among all other vegetable oils which are of paramount importance for human health. VOO constituents are also responsible of its peculiar flavor, a complex sensation due to a combination of aroma, taste, texture, and mouthfeel or trigeminal sensations. VOO flavor depends primarily on the concentration and nature of volatile and phenolic compounds present in olive oil which can change dramatically depending on agronomical and technological factors. Another aspect that can change the flavor perception is linked to the oral process during olive oil tasting. In fact, in this case, some human physiological and matrix effects modulate the flavor release in the mouth.
  • 728
  • 25 Feb 2021
Topic Review
Virally Infected Donor Grafts
The ideal management for end stage liver disease, acute liver failure, and hepatocellular carcinoma (HCC), within specific criteria, is liver transplantation (LT). Due to continuous increase in LT cases, there has been consideration to increase utilization of organs from donor livers which were previously discarded, including virally infected donor livers. 
  • 388
  • 07 Jan 2022
Topic Review
Viral Zoonotic Diseases and Male Reproduction
Zoonotic diseases occur as a result of human interactions with animals with the inadvertent transmission of pathogens from one to another. Zoonoses remain a major cause of morbidity and mortality among human populations, as they have been a source of pandemics in human history. Viral zoonoses account for a significant percentage of pathogens of zoonotic sources, posing a huge risk to men’s general health and fertility. Evidence from reviewed articles showed that viral zoonotic diseases elicit an immune reaction that induces inflammatory mediators and impairs testicular functions such as spermatogenesis and steroidogenesis, leading to abnormal semen parameters that lead to subfertility/infertility. Although most zoonotic viruses linger in semen long after recovery, their presence in semen does not directly translate to sexual transmission. 
  • 445
  • 20 Dec 2022
Topic Review
Viral Video
A viral video is a video that becomes popular through a viral process of Internet sharing, typically through video sharing websites such as YouTube as well as social media and email. Viral videos may be serious, and some are deeply emotional, but many more are centered on entertainment and humorous content. They may include televised comedy sketches, such as The Lonely Island's "Lazy Sunday" and "Dick in a Box", Numa Numa videos, The Evolution of Dance, Chocolate Rain on YouTube; and web-only productions such as I Got a Crush... on Obama. Some eyewitness events have also been caught on video and have "gone viral" such as the Battle at Kruger. One commentator called the Kony 2012 video the most viral video in history (about 34,000,000 views in three days and 100,000,000 views in six days), but "Gangnam Style" (2012) received one billion views in five months and was the most viewed video on YouTube from 2012 until "Despacito" (2017).
  • 810
  • 21 Oct 2022
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