Researchers at ETH Zurich recently identified a previously unknown compartment in mammalian cells. They have named it the exclusome. It is made up of DNA rings known as plasmids. The researchers have published details of ...
Cell & Microbiology
Oct 2, 2023
0
716
(Phys.org)—Worldwide, many strains of the bacterium Staphyloccocus aureus, commonly known as staph infections, are already resistant to all antibiotics except vancomycin. But as bacteria are becoming resistant to this once ...
Cell & Microbiology
Jan 30, 2013
2
0
A component of the human intestinal flora that has been little studied to date is the focus of a new study from Germany. Plasmids are small extrachromosomal genetic elements that frequently occur in bacterial cells and can ...
Cell & Microbiology
Apr 16, 2024
0
104
When most people think about bacterial antibiotic resistance, they think about it occurring in bacteria found in people or animals. But the environment surrounding us is a huge bacterial reservoir, and antibiotic resistance ...
Cell & Microbiology
Oct 6, 2017
0
552
A new study led by scientists at the University of Oxford has found that small DNA molecules known as plasmids are one of the key culprits in spreading the major global health threat of antibiotic resistance.
Evolution
Nov 8, 2016
0
72
Everyone's talking about CRISPR-Cas. This biotechnological method offers a relatively quick and easy way to manipulate single genes in cells, meaning they can be precisely deleted, replaced or modified. Furthermore, in recent ...
Biotechnology
Aug 14, 2019
8
130
All species mark their DNA with methyl groups. This is done to regulate gene expression, distinguish indigenous DNA from foreign DNA, or to mark old DNA strands during replication. Methylation is carried out by certain enzymes ...
Cell & Microbiology
Aug 19, 2019
0
255
Scientists from New Zealand's University of Otago and the Netherlands are continuing to unlock the secrets of a surprisingly flexible bacterial immune system, called CRISPR-Cas.
Cell & Microbiology
Oct 3, 2016
0
137
In recent years, the development of CRISPR technologies and gene-editing scissors in particular have taken the world by storm. Indeed, scientists have learned how to harness these clever natural systems in the biotech and ...
Biotechnology
Mar 24, 2020
0
99
Like humans, bacteria have various immune systems to defend against pathogens such as viruses. These immune systems usually degrade the DNA of the pathogens to make it harmless. In the research group of assistant Professor ...
Cell & Microbiology
Apr 4, 2022
0
185
In microbiology and genetics, a plasmid is a DNA molecule that is separate from, and can replicate independently of, the chromosomal DNA. They are double-stranded and, in many cases, circular. Plasmids usually occur naturally in bacteria, but are sometimes found in eukaryotic organisms (e.g., the 2-micrometre ring in Saccharomyces cerevisiae).
Plasmid sizes vary from 1 to over 1,000 kbp. The number of identical plasmids in a single cell can range anywhere from one to even thousands under some circumstances. Plasmids can be considered part of the mobilome because they are often associated with conjugation, a mechanism of horizontal gene transfer.
The term plasmid was first introduced by the American molecular biologist Joshua Lederberg in 1952.
Plasmids are considered "replicons", capable of autonomous replication within a suitable host. Plasmids can be found in all three major domains: Archaea, Bacteria, and Eukarya. Similar to viruses, plasmids are not considered by some to be a form of "life". Unlike viruses, plasmids are "naked" DNA and do not encode genes necessary to encase the genetic material for transfer to a new host, though some classes of plasmids encode the sex pilus necessary for their own transfer. Plasmid host-to-host transfer requires direct, mechanical transfer by conjugation or changes in host gene expression allowing the intentional uptake of the genetic element by transformation. Microbial transformation with plasmid DNA is neither parasitic nor symbiotic in nature, because each implies the presence of an independent species living in a commensal or detrimental 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. Plasmids can also provide bacteria with the ability to fix elemental nitrogen or to degrade recalcitrant organic compounds that provide an advantage when nutrients are scarce.
This text uses material from Wikipedia, licensed under CC BY-SA
