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The restriction modification system (RM system) is found in bacteria and archaea, and provides a defense against foreign DNA, such as that borne by bacteriophages.. Bacteria have restriction enzymes, also called restriction endonucleases, which cleave double-stranded DNA at specific points into fragments, which are then degraded further by other endonucleases.
Type I secretion system (T1SS or TOSS) is found in Gram-negative bacteria. It depends on chaperone activity using Hly and Tol proteins. The system activates as a signal sequence HlyA binds HlyB on the cell membrane. This signal sequence is an ABC transporter. The HlyAB complex activates HlyD which uncoils and moves to the outer cell membrane.
The repressor found in the phage lambda is a notable example of the level of control possible over gene expression by a very simple system. As discovered by Barbara J. Meyer , [ 23 ] it forms a 'binary switch' with two genes under mutually exclusive expression.
A human pathogen is a pathogen (microbe or microorganism such as a virus, bacterium, prion, or fungus) that causes disease in humans.. The human physiological defense against common pathogens (such as Pneumocystis) is mainly the responsibility of the immune system with help by some of the body's normal microbiota.
Bacteria resist phage infection through restriction modification systems that degrade foreign DNA [145] and a system that uses CRISPR sequences to retain fragments of the genomes of phage that the bacteria have come into contact with in the past, which allows them to block virus replication through a form of RNA interference.
Structural model at atomic resolution of bacteriophage T4 [1] The structure of a typical myovirus bacteriophage Anatomy and infection cycle of bacteriophage T4.. A bacteriophage (/ b æ k ˈ t ɪər i oʊ f eɪ dʒ /), also known informally as a phage (/ ˈ f eɪ dʒ /), is a virus that infects and replicates within bacteria and archaea.
Pathogenic bacteria are bacteria that can cause disease. [1] This article focuses on the bacteria that are pathogenic to humans. Most species of bacteria are harmless and many are beneficial but others can cause infectious diseases. The number of these pathogenic species in humans is estimated to be fewer than a hundred. [2]
While tetanus toxin is produced from Clostridium tetani, a spore forming bacteria found in soil, Tetanus is a paralytic disease that is global and commonly affects newborns as well as non-immunized individuals. Tetanus enters the body of organisms through wounds or skin breaks and can be found in manure, soil, and dust.