Bacteria (/ bækˈtɪəriə / (listen); common noun bacteria, singular bacterium) are a type of biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a number of shapes, ranging from spheres to rods and spirals.
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From Wikipedia, the free encyclopedia The genus Bacterium was a taxon described in 1828 by Christian Gottfried Ehrenberg. The type species was later changed from Bacterium triloculare to Bacterium coli (now Escherichia coli) as it was lost.
Bacteria are made up of one cell, so they are a kind of unicellular organism. They are among the simplest single-celled organisms on Earth, and were one of the earliest forms of life. They include a number of extremophiles which live in extreme habitats. There are probably more individual bacteria than any other sort of organism on the planet.
- Importance of the outer cell membrane in bacterial classification
- Bacterial transformation
In bacteriology, Gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their cell wall. Gram-positive bacteria take up the crystal violet stain used in the test, and then appear to be purple-coloured when seen through an optical microscope. This is because the thick peptidoglycan layer in the bacterial cell wall retains the stain after it is washed away from the rest
In general, the following characteristics are present in gram-positive bacteria: Cytoplasmic lipid membrane Thick peptidoglycan layer Teichoic acids and lipoids are present, forming lipoteichoic acids, which serve as chelating agents, and also for certain types of adherence. Peptidoglycan chains are cross-linked to form rigid cell walls by a bacterial enzyme DD-transpeptidase. A much smaller volume of periplasm than that in gram-negative bacteria. Only some species have a capsule, usually consis
Along with cell shape, Gram staining is a rapid method used to differentiate bacterial species. Such staining, together with growth requirement and antibiotic susceptibility testing, and other macroscopic and physiologic tests, forms the full basis for classification and subdivision of the bacteria. Species identification hierarchy in clinical settings Historically, the kingdom Monera was divided into four divisions based primarily on Gram staining: Firmicutes, Gracilicutes, Mollicutes and Mendo
Although bacteria are traditionally divided into two main groups, gram-positive and gram-negative, based on their Gram stain retention property, this classification system is ambiguous as it refers to three distinct aspects, which do not necessarily coalesce for some bacterial species. The gram-positive and gram-negative staining response is also not a reliable characteristic as these two kinds of bacteria do not form phylogenetic coherent groups. However, although Gram staining response is an e
In the classical sense, six gram-positive genera are typically pathogenic in humans. Two of these, Streptococcus and Staphylococcus, are cocci. The remaining organisms are bacilli and can be subdivided based on their ability to form spores. The non-spore formers are Corynebacterium and Listeria, whereas Bacillus and Clostridium produce spores. The spore-forming bacteria can again be divided based on their respiration: Bacillus is a facultative anaerobe, while Clostridium is an obligate anaerobe.
Transformation is one of three processes for horizontal gene transfer, in which exogenous genetic material passes from a donor bacterium to a recipient bacterium, the other two processes being conjugation and transduction. In transformation, the genetic material passes through the intervening medium, and uptake is completely dependent on the recipient bacterium. As of 2014 about 80 species of bacteria were known to be capable of transformation, about evenly divided between gram-positive and gram
Jun 03, 2020 · In most formal writing, bacterium is the singular form of the noun, and bacteria the plural form. This is in accord with the word's Latin etymology. However, in ordinary speech, some speakers use bacteria as a singular, with plural either bacteria or bacterias. This is usually considered nonstandard.
Bifidobacterium is a genus of gram-positive, nonmotile, often branched anaerobic bacteria. They are ubiquitous inhabitants of the gastrointestinal tract, vagina and mouth (B. dentium) of mammals, including humans. Bifidobacteria are one of the major genera of bacteria that make up the gastrointestinal tract microbiota in mammals.
Pathogenic bacteria are bacteria that can cause disease. This article deals with human pathogenic bacteria. Although most bacteria are harmless or often beneficial, some are pathogenic, with the number of species estimated as fewer than a hundred that are seen to cause infectious diseases in humans.SpeciesSpeciesTransmissionDiseasesActinomycosis: painful abscesses in the mouth, lungs, or gastrointestinal tract.Contact with cattle, sheep, goats and horses Spores enter through inhalation or through abrasionsAnthrax: pulmonary, gastrointestinal and/or cutaneous symptoms.Abscesses in gastrointestinal tract, pelvic cavity and lungsContact with respiratory droplets expelled by infected human hosts.Whooping cough Secondary bacterial pneumonia
Bacillus (Latin "stick") is a genus of Gram-positive, rod-shaped bacteria, a member of the phylum Firmicutes, with 266 named species. The term is also used to describe the shape (rod) of certain bacteria; and the plural Bacilli is the name of the class of bacteria to which this genus belongs.
From Wikipedia, the free encyclopedia Helicobacter pylori, previously known as Campylobacter pylori, is a gram-negative, helically-shaped, microaerophilic bacterium usually found in the stomach.
Directed by Brett Piper. With Alison Whitney, Benjamin Kanes, Miya Sagara, Andrew Kranz. When a handful of friends stumble upon the abandoned building, they come face to face with a biological weapons experiment gone catastrophically wrong.
- Brett Piper