Crossword clues for plasmid
The Collaborative International Dictionary
Plasmid \Plas"mid\, n. (Molecular genetics) A piece of DNA, usually circular, functioning as part of the genetic material of a cell, not integrated with the chromosome and replicating independently of the chromosome, but transferred, like the chromosome, to subsequent generations of daughter cells. In bacteria, plasmids often carry the genes for antibiotic resistance; they are exploited in genetic engineering as the vehicles for introduction of extraneous DNA into cells, to alter the genetic makeup of the cell. The cells thus altered may produce desirable proteins which are extracted and used; in the case of genetically altered plant cells, the altered cells may grow into complete plants with changed properties, as for example, increased resistance to disease.
Douglas Harper's Etymology Dictionary
1952, from plasma + -id.
Wiktionary
n. (context cytology English) A loop of double-stranded DNA that is separate from and replicates independently of the chromosomes, most commonly found in bacterium, but also in archaeans and eukaryote cells, and used in genetic engineering as a vector for gene transfer.
WordNet
n. a small cellular inclusion consisting of a ring of DNA that is not in a chromosome but is capable of autonomous replication
Wikipedia
A plasmid is a small DNA molecule within a cell that is physically separated from a chromosomal DNA and can replicate independently. They are most commonly found in bacteria as small circular, double-stranded DNA molecules; however, plasmids are sometimes present in archaea and eukaryotic organisms. In nature, plasmids often carry genes that may benefit the survival of the organism, for example antibiotic resistance. While the chromosomes are big and contain all the essential genetic information for living under normal conditions, plasmids usually are very small and contain only additional genes that may be useful to the organism under certain situations or particular conditions. Artificial plasmids are widely used as vectors in molecular cloning, serving to drive the replication of recombinant DNA sequences within host organisms.
Plasmids are considered replicons, a unit of DNA capable of replicating autonomously within a suitable host. However, plasmids, like viruses, are not generally classified as life. Plasmids can be transmitted from one bacterium to another (even of another species) via three main mechanisms: transformation, transduction, and conjugation. This host-to-host transfer of genetic material is called horizontal gene transfer, and plasmids can be considered part of the mobilome. Unlike viruses (which encase their genetic material in a protective protein coat called a capsid), plasmids are "naked" DNA and do not encode genes necessary to encase the genetic material for transfer to a new host. However, some classes of plasmids encode the conjugative "sex" pilus necessary for their own transfer. The size of the plasmid varies from 1 to over 200 k bp, and the number of identical plasmids in a single cell can range anywhere from one to thousands under some circumstances.
The relationship between microbes and plasmid DNA is neither parasitic nor mutualistic, because each implies the presence of an independent species living in a detrimental or commensal state with the host organism. Rather, plasmids provide a mechanism for horizontal gene transfer within a population of microbes and typically provide a selective advantage under a given environmental state. Plasmids may carry genes that provide resistance to naturally occurring antibiotics in a competitive environmental niche, or the proteins produced may act as toxins under similar circumstances, or allow the organism to utilize particular organic compounds that would be advantageous when nutrients are scarce.
Usage examples of "plasmid".
Wearily he began assembling the components of another plasmid from the DNA fragments he had in storage.
Now, somewhere along the line, when these guys were trying to design a plasmid to change covalent chlorine to ionic, they had to consider the possibility of making it go the other way.
A number of different antibiotics have been shown to promote plasmid transfer between different bacteria, and it might even be considered that some antibiotics are bacterial pheromones.
The plasmid was accompanied by a transcription factor which would activate it.
Creating the viruses would be a tricky but not impossible problem in plasmid engineering.
Frederic Bushman, 2002, Cold Spring Harbor Laboratory Press, is an important synopsis of what is currently known about DNA transfer through viruses, transposons, plasmids, etc.
Each family of linear plasmids contains variations on a set of closely associated genes, like sentences built from the same small vocabulary, but there are also rogue genes distributed randomly among all the families.
They had his genome in their records, but it would take a few days to synthesize the collection of repair strands and clip them onto plasmids, and clone millions more.
DNA, built from scratch from the appropriate amino acids, then multiplied by polymerase chain reactions, were spliced into bacterial plasmids, which acted as vectors to transmit the recombinant genes to the nucleus of the egg itself.
Put together some chlorine-processing plasmids and implanted them in a particular bug called Escherichiacoli.
They not only share DNA among members of their own species, through conjugation and transduction, but they will encode DNA in plasmids and transposons and packet-mail it to other species.
Science News Service deduced his interest in plasmids from his purchase of olephages.
Some plasmids are capable of splicing themselves seamlessly into a chromosome.
A virulent strain of staphylococcus aureus has incorporated endozine-resistant plasmids from enterococcus.
Science News Service deduced his interest in plasmids from his purchase of olephages.