Pilus

Information about Pilus

Schematic drawing of bacterial conjugation. 1- Donor cell produces pilus. 2- Pilus attaches to recipient cell, brings the two cells together. 3- The mobile plasmid is nicked and a single strand of DNA is then transferred to the recipent cell. 4- Both cells recircularize their plasmids, synthesize second strands, and reproduce pili; both cells are now viable donors.

A pilus (Latin for 'hair'; plural : pili) is a hairlike appendage found on the surface of many bacteria. The terms pilus and fimbria (Latin for 'thread' or 'fiber'; plural: fimbriae) are often used interchangeably, although some researchers reserve the term pilus for the sexual appendage required for bacterial conjugation. All pili are primarily composed of oligomeric pilin proteins.

Pili

Pili connect the bacterium to another of its species, or to another bacterium of a different species, and build a bridge between the cytoplasms of either cell. That enables the transfer of plasmids between the bacteria. An exchanged plasmid can add new functions to a bacterium, e.g., an antibiotic resistance.

Up to ten of these structures can exist on the bacteria. Some bacterial viruses or bacteriophages attach to receptors on sex pili at the start of their reproductive cycle.

Despite its name, the sex pilus is not used for sexual reproduction, and cannot be equated with a penis, although such comparisons are often used to ease understanding.

A pilus is typically 9 to 10 nm in diameter. The pilus allows for the transfer of bacterial DNA from the bacteria with the pilus (donor) to the recipient bacteria. Through this mechanism of genetic transformation, advantageous genetic traits can be disseminated amongst a population of bacteria. Not all bacteria have the ability to create sex pili, however sex pili can form between bacteria of different species.

It is an extension of the cytoplasm and used for conjugation with another cell of the same species.

Some pili, designated type IV pili, generate motile forces. The external termini of the pili adhere to solid substrate, either the surface to which the bacteria are attached or to other bacteria, and subsequent pilus contraction pulls the bacteria forward, not unlike a grappling hook. As type IV pilus-mediated movement is typically jerky, it is called twitching motility, as distinct from other forms of bacterial motility, such as are mediated by flagella. However, in Myxococcus xanthus, this movement is quite fluid.

Fimbriae

Attachment of bacteria to host surfaces is required for colonization during infection or to initiate formation of a biofilm. A fimbria is a short pilus that is used to attach the bacterium to a surface. Fimbriae are either located at the poles of a cell, or are evenly spread over its entire surface. Mutant bacteria that lack fimbriae cannot adhere to their usual target surfaces and, thus, cannot cause diseases.

Some fimbriae can contain lectins. The lectins are necessary to adhere to target cells because they can recognize oligosaccharide units on the surface of these target cells. Other fimbriae bind to components of the extracellular matrix.

Fimbriae are found in both Gram-negative and Gram-positive bacteria. In Gram positive bacteria, the pilin subunits are covalently linked.

Antibiotic resistance is the ability of a microorganism to withstand the effects of an antibiotic. It is a specific type of drug resistance. Antibiotic resistance evolves naturally via natural selection through random mutation, but it could also be engineered.
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bacteriophage (from 'bacteria' and Greek phagein, 'to eat') is any one of a number of viruses that infect bacteria. The term is commonly used in its shortened form, phage.

Typically, bacteriophages consist of an outer protein hull enclosing genetic material.
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For other uses, see Receptor.

In biochemistry, a receptor is a protein on the cell membrane or within the cytoplasm or cell nucleus that binds to a specific molecule (a ligand), such as a neurotransmitter, hormone, or other substance, and initiates
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Sexual reproduction is a union that results in increasing genetic diversity of the offspring. It is characterized by two processes: meiosis, involving the halving of the number of chromosomes; and fertilisation, involving the fusion of two gametes and the restoration of the
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For the symbol of the erect penis, see phallus.

The penis (plural penises, penes) is an external sexual organ of certain biologically male organisms.
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NM may stand for:

National Master, a chess title
Nautical mile, a unit of length used for maritime and aviation purposes
Neal Morse, an American multi-instrumentalist
Network marketing, a business model that combines direct marketing with franchising

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Genetic engineering, recombinant DNA technology, genetic modification/manipulation (GM) and gene splicing are terms that are applied to the direct manipulation of an organisms genes.
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In molecular biology, Transformation is the genetic alteration of a cell resulting from the uptake and expression of foreign genetic material (DNA). Separate terms are used for genetic alterations resulting from introduction of DNA by plasmid-encoded conjugation or by viruses
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character is an attribute of an organism that allows it to be compared with another. In genetics this refers to heritable features which can exist in more than one state.^[1] A trait
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Cytoplasm is a gelatinous, semi-transparent fluid that fills most cells. Eukaryotic cells contain a nucleus that is kept separate from the cytoplasm by a double membrane layer. The cytoplasm has three major elements; the cytosol, organelles and inclusions.
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species is one of the basic units of biological classification. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring.
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For the insect anatomical structure, see .

A flagellum (plural: flagella) is a long, slender projection from the cell body, composed of microtubules and surrounded by the plasma membrane.
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M. xanthus

Binomial name
Myxococcus xanthus
Beebe 1941

Myxococcus xanthus exists as a self-organized, predatory, saprophytic, single-species biofilm called a swarm.
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biofilm is a complex aggregation of microorganisms marked by the excretion of a protective and adhesive matrix. Biofilms are also often characterized by surface attachment, structural heterogeneity, genetic diversity, complex community interactions, and an extracellular matrix of
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In bacteriology, fimbria is a proteinaceous appendage in many gram-negative bacteria that is thinner and shorter than a flagellum. This appendage ranges from 3-10 nanometers in diameter and can be up to several micrometers long.
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mutant is an individual, organism, or new genetic character arising or resulting from an instance of mutation, which is a sudden structural change within the DNA of a gene or chromosome of an organism resulting in the creation of a new character or trait not found in the wildtype.
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disease is an abnormal condition of an organism that impairs bodily functions. In human beings, "disease" is often used more broadly to refer to any condition that causes discomfort, dysfunction, distress, social problems, and/or death to the person afflicted, or similar problems
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Lectins are carbohydrate-binding proteins or glycoproteins which are highly specific for their sugar moieties.

Etymology

The name ‘lectin’ is derived from the Latin word legere, meaning ‘to select’.
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An oligosaccharide is a saccharide polymer containing a small number (typically three to ten^[1]) of component sugars, also known as simple sugars.

They are generally found either O- or N
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extracellular matrix (ECM) is the extracellular part of animal tissue that usually provides structural support to the cells in addition to performing various other important functions. The extracellular matrix is the defining feature of connective tissue in animals.
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Gram-negative bacteria are those that do not retain crystal violet dye in the Gram staining protocol.^[1] Gram-positive bacteria will retain the dark blue dye after an alcohol wash.
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Gram-positive bacteria are those that retain a crystal violet dye during the Gram stain process.^[1] Gram-positive bacteria appear blue or violet under a microscope, while Gram-negative bacteria appear red or pink.
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