|
Viriome
The viriome of a habitat or environment is the total virus content within it. A viriome may relate to the viruses that inhabit a multicellular organism as well as the phages that are residing inside bacteria and archaea. This term exists in contrast to the virome, which more commonly refers to the collection of nucleic acids contained by viruses in a microbiome. See also * Human virome * Non-cellular life * Microbiology *Metagenomics Metagenomics is the study of genetic material recovered directly from environmental or clinical samples by a method called sequencing. The broad field may also be referred to as environmental genomics, ecogenomics, community genomics or microb ... References Viruses {{virus-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phages
A bacteriophage (), also known informally as a ''phage'' (), is a duplodnaviria virus that infects and replicates within bacteria and archaea. The term was derived from "bacteria" and the Greek φαγεῖν ('), meaning "to devour". Bacteriophages are composed of proteins that encapsulate a DNA or RNA genome, and may have structures that are either simple or elaborate. Their genomes may encode as few as four genes (e.g. MS2) and as many as hundreds of genes. Phages replicate within the bacterium following the injection of their genome into its cytoplasm. Bacteriophages are among the most common and diverse entities in the biosphere. Bacteriophages are ubiquitous viruses, found wherever bacteria exist. It is estimated there are more than 1031 bacteriophages on the planet, more than every other organism on Earth, including bacteria, combined. Viruses are the most abundant biological entity in the water column of the world's oceans, and the second largest component of biomas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Habitat
In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical manifestation of its ecological niche. Thus "habitat" is a species-specific term, fundamentally different from concepts such as environment or vegetation assemblages, for which the term "habitat-type" is more appropriate. The physical factors may include (for example): soil, moisture, range of temperature, and light intensity. Biotic factors will include the availability of food and the presence or absence of predators. Every species has particular habitat requirements, with habitat generalist species able to thrive in a wide array of environmental conditions while habitat specialist species requiring a very limited set of factors to survive. The habitat of a species is not necessarily found in a geographical area, it can be the interior ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virus
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. Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898,Dimmock p. 4 more than 9,000 virus species have been described in detail of the millions of types of viruses in the environment. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. 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 the process of infecting a cell, viruses exist in the form of independent particles, or ''virions'', consisting of (i) the genetic material, i. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multicellular Organism
A multicellular organism is an organism that consists of more than one cell, in contrast to unicellular organism. All species of animals, land plants and most fungi are multicellular, as are many algae, whereas a few organisms are partially uni- and partially multicellular, like slime molds and social amoebae such as the genus ''Dictyostelium''. Multicellular organisms arise in various ways, for example by cell division or by aggregation of many single cells. Colonial organisms are the result of many identical individuals joining together to form a colony. However, it can often be hard to separate colonial protists from true multicellular organisms, because the two concepts are not distinct; colonial protists have been dubbed "pluricellular" rather than "multicellular". There are also multinucleate though technically unicellular organisms that are macroscopic, such as the xenophyophorea that can reach 20 cm. Evolutionary history Occurrence Multicellularity has evolved ind ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of dead bodies; bacteria are responsible for the putrefaction stage in this process. In the biological communities surrounding hydrothermal vents and cold seeps, extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane, to energy. Bacteria also live in symbiotic and parasitic relationsh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaea
Archaea ( ; singular archaeon ) is a domain of single-celled organisms. These microorganisms lack cell nuclei and are therefore prokaryotes. Archaea were initially classified as bacteria, receiving the name archaebacteria (in the Archaebacteria kingdom), but this term has fallen out of use. Archaeal cells have unique properties separating them from the other two domains, Bacteria and Eukaryota. Archaea are further divided into multiple recognized phyla. Classification is difficult because most have not been isolated in a laboratory and have been detected only by their gene sequences in environmental samples. Archaea and bacteria are generally similar in size and shape, although a few archaea have very different shapes, such as the flat, square cells of ''Haloquadratum walsbyi''. Despite this morphological similarity to bacteria, archaea possess genes and several metabolic pathways that are more closely related to those of eukaryotes, notably for the enzymes involved ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virome
Virome refers to the assemblage of viruses that is often investigated and described by metagenomic sequencing of viral nucleic acids that are found associated with a particular ecosystem, organism or holobiont. The word is frequently used to describe environmental viral shotgun metagenomes. Viruses, including bacteriophages, are found in all environments, and studies of the virome have provided insights into nutrient cycling, development of immunity, and a major source of genes through lysogenic conversion. History The first comprehensive studies of viromes were by shotgun community sequencing, which is frequently referred to as metagenomics. In the 2000s, the Rohwer lab sequenced viromes from seawater, marine sediments, adult human stool, infant human stool, soil, and blood. This group also performed the first RNA virome with collaborators from the Genomic Institute of Singapore. From these early works, it was concluded that most of the genomic diversity is contained in the gl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleic Acids
Nucleic acids are biopolymers, macromolecules, essential to all known forms of life. They are composed of nucleotides, which are the monomers made of three components: a 5-carbon sugar, a phosphate group and a nitrogenous base. The two main classes of nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). If the sugar is ribose, the polymer is RNA; if the sugar is the ribose derivative deoxyribose, the polymer is DNA. Nucleic acids are naturally occurring chemical compounds that serve as the primary information-carrying molecules in cells and make up the genetic material. Nucleic acids are found in abundance in all living things, where they create, encode, and then store information of every living cell of every life-form on Earth. In turn, they function to transmit and express that information inside and outside the cell nucleus to the interior operations of the cell and ultimately to the next generation of each living organism. The encoded information is co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microbiome
A microbiome () is the community of microorganisms that can usually be found living together in any given habitat. It was defined more precisely in 1988 by Whipps ''et al.'' as "a characteristic microbial community occupying a reasonably well-defined habitat which has distinct physio-chemical properties. The term thus not only refers to the microorganisms involved but also encompasses their theatre of activity". In 2020, an international panel of experts published the outcome of their discussions on the definition of the microbiome. They proposed a definition of the microbiome based on a revival of the "compact, clear, and comprehensive description of the term" as originally provided by Whipps ''et al.'', but supplemented with two explanatory paragraphs. The first explanatory paragraph pronounces the dynamic character of the microbiome, and the second explanatory paragraph clearly separates the term ''microbiota'' from the term ''microbiome''. The microbiota consists of all ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Virome
The human virome is the total collection of viruses in and on the human body. Viruses in the human body may infect both human cells and other microbes such as bacteria (as with bacteriophages). Some viruses cause disease, while others may be asymptomatic. Certain viruses are also integrated into the human genome as proviruses or endogenous viral elements. Viruses evolve rapidly and hence the human virome changes constantly. Every human being has a unique virome with a unique balance of species. Lifestyle, age, geographic location, and even the season of the year can affect an individual's exposure to viruses, and one's susceptibility to any disease that might be caused by those viruses is also affected by pre-existing immunity and both viral and human genetics. The human virome is far from being completely explored and new viruses are discovered frequently. Unlike the roughly 40 trillion bacteria in a typical human microbiome, an estimate of the number of viral particles in a he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Non-cellular Life
Non-cellular life, or acellular life is life that exists without a cellular structure for at least part of its life cycle. Historically, most (descriptive) definitions of life postulated that an organism must be composed of one or more cells, but this is no longer considered necessary, and modern criteria allow for forms of life based on other structural arrangements. The primary candidates for non-cellular life are viruses. Some biologists consider viruses to be organisms, but others do not. Their primary objection is that no known viruses are capable of autonomous reproduction: they must rely on cells to copy them. Engineers sometimes use the term "artificial life" to refer to software and robots inspired by biological processes, but these do not satisfy any biological definition of life. Viruses as non-cellular life The nature of viruses was unclear for many years following their discovery as pathogens. They were described as poisons or toxins at first, then as "infectio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microbiology
Microbiology () is the scientific study of microorganisms, those being unicellular (single cell), multicellular (cell colony), or acellular (lacking cells). Microbiology encompasses numerous sub-disciplines including virology, bacteriology, protistology, mycology, immunology, and parasitology. Eukaryotic microorganisms possess membrane-bound organelles and include fungi and protists, whereas prokaryotic organisms—all of which are microorganisms—are conventionally classified as lacking membrane-bound organelles and include Bacteria and Archaea. Microbiologists traditionally relied on culture, staining, and microscopy. However, less than 1% of the microorganisms present in common environments can be cultured in isolation using current means. Microbiologists often rely on molecular biology tools such as DNA sequence based identification, for example the 16S rRNA gene sequence used for bacteria identification. Viruses have been variably classified as organisms, as they have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.JPG "Click for more on -> Habitat")
.jpg "Click for more on -> Archaea")
