Vector

In medicine, a vector is a carrier. The best way to understand a vector is to recall its origin as a word. Vector is the Latin word for a "bearer." In parasitology (the study of parasitic organisms), the vector carries the parasitic agent. For example, in malaria a mosquito serves as the vector that carries and transfers the infectious agent (Plasmodium), injecting it with a bite. In molecular biology, a vector may be a virus (or a plasmid); a piece of foreign DNA is inserted in the vector genome to be carried and introduced into a recipient (host) cell. In physics, there are vectors but they go beyond the biomedical realm (except in cardiology).

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1. An invertebrate animal ( e.g., tick, mite, mosquito, bloodsucking fly) capable of transmitting an infectious agent among vertebrates. 2. Anything ( e.g., velocity, mechanical force, electromotive force) having magnitude and direction; it can be represented by a straight line of appropriate length and direction. 3. The net electrical axis of any ECG wave (usually QRS) whose length is proportional to the magnitude of the electrical force, whose direction gives the direction of the force, and whose tip represents the positive pole of the force. 4. DNA such as a chromosome or plasmid that autonomously replicates in a cell to which another DNA segment may be inserted and be itself replicated, as in cloning. 5. SYN: recombinant v.. 6. Recombinant DNA systems especially suited for production of large quantities of specific proteins in bacterial, yeast, insect, or mammalian cell systems. [L. v., a carrier]

- biologic v. a v., such as the Anopheles mosquito for malarial agents or the tsetse fly for agents of African sleeping sickness, in which the agent multiplies prior to being transmitted to another host.

- cloning v. an autonomously replicating plasmid or phage with regions that are not essential for its propagation in bacteria and into which foreign DNA can be inserted; this foreign DNA is replicated and propagated as if it were a normal component of the v..

- expression v. a v. (plasmid, yeast, or animal virus genome) used experimentally to introduce foreign genetic material into a propagatable host cell in order to replicate and amplify the foreign DNA sequences as a recombinant molecule (recombinant DNA cloning of sequences).

- instantaneous v. the resultant v. of the heart's action currents at any given moment, usually represented as an arrow of appropriate direction and magnitude.

- manifest v. projection of a spatial cardiac v. on a single plane.

- mean v. a single cardiac v. representing the average of all vectors present during a given time interval. SYN: mean manifest v..

- mean manifest v. SYN: mean v..

- mechanical v. a v. that conveys pathogens to a susceptible individual without essential biologic development of the pathogens in the v., as in the transfer of septic organisms on the feet or mouth parts of the housefly.

- recombinant v. a v. into which a foreign DNA has been inserted. SYN: v. (5).

- retroviral v. a specially constructed retrovirus containing one or more genes to correct certain genetic disorders.

- shuttle v. a v. (4) that contains both bacterial and eukaryotic replication signals; thus, replication can occur in both types of cells.

- spatial v. a cardiac v. represented in more than one plane simultaneously; two- or three-dimensional orientation of a v..

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vec·tor 'vek-tər n

1) a quantity that has magnitude and direction and that is usu. represented by part of a straight line with the given direction and with a length representing the magnitude

2) an organism (as an insect) that transmits a pathogen from one organism or source to another <fleas are \vectors of plague> compare CARRIER (1a)

3) an agent (as a plasmid or virus) that contains or carries modified genetic material (as recombinant DNA) and can be used to introduce exogenous genes into the genome of an organism

vec·to·ri·al vek-'tōr-ē-əl, -'tȯr- adj

vector vt, vec·tored; vec·tor·ing -t(ə-)riŋ to transmit (a pathogen or disease) from one organism to another: act as a vector for <a disease \vectored by flies>

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n.

1. an animal, usually an insect or a tick, that transmits parasitic microorganisms - and therefore the diseases they cause - from person to person or from infected animals to human beings. Mosquitoes, for example, are vectors of malaria, filariasis, and yellow fever.

2. an agent used to insert a foreign gene or DNA fragment into a bacterial or other cell in genetic engineering and gene therapy. Viruses, especially retroviruses, are often used as vectors: once inside the host cell, the virus can replicate and thus produce copies (clone) of the gene.

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vec·tor (vekґtər) [L. “one who carries,” from vehere to carry] 1. a carrier, especially the animal (usually an arthropod) that transfers an infective agent from one host to another. 2. cloning v. 3. a quantity possessing magnitude and direction and commonly represented by a straight line resembling an arrow: the length of the line denotes magnitude and the arrowhead and the position of the line with respect to an axis of reference denote direction. 4. in mathematics, an ordered set of values. For example, the vector x denotes the ordered set (x₁,x₂,…x_n).