Biomaterial Database

Methods and reagents. preparing ultra-competent Escherichia coli. 1996

P N Hengen

National Cancer Institute, Frederick Cancer Research and Development Center, MD 21702-1201, USA. pnh@ncifcrf.gov

Methods and Reagents is a unique monthly column that highlights current discussions in the newsgroup blonet.molblo.methds-reagnts, available on the internet. This month's column discusses how to get the most out of your transformation procedure and how to prepare your own ultra-competent Escherichia coli cells. For details on how to partake in the newsgroup, see the accompanying box.

UI	MeSH Term	Description	Entries
D010957	Plasmids	Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.	Episomes,Episome,Plasmid
D003195	Computer Communication Networks	A system containing any combination of computers, computer terminals, printers, audio or visual display devices, or telephones interconnected by telecommunications equipment or cables: used to transmit or receive information. (Random House Unabridged Dictionary, 2d ed)	Cognitive Radio,Computer Network Management,Databases, Distributed,Distributed Systems,Extranets,Intranets,Network Communication Protocols,Telecommunication Networks,Cognitive Radios,Communication Network, Computer,Communication Networks, Computer,Communication Protocol, Network,Communication Protocols, Network,Computer Communication Network,Database, Distributed,Distributed Database,Distributed Databases,Distributed System,Extranet,Intranet,Management, Computer Network,Network Communication Protocol,Network Management, Computer,Network, Computer Communication,Network, Telecommunication,Protocol, Network Communication,Radio, Cognitive,System, Distributed,Telecommunication Network
D003470	Culture Media	Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.	Media, Culture
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D013438	Sulfhydryl Compounds	Compounds containing the -SH radical.	Mercaptan,Mercapto Compounds,Sulfhydryl Compound,Thiol,Thiols,Mercaptans,Compound, Sulfhydryl,Compounds, Mercapto,Compounds, Sulfhydryl
D013696	Temperature	The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.	Temperatures
D014169	Transformation, Bacterial	The heritable modification of the properties of a competent bacterium by naked DNA from another source. The uptake of naked DNA is a naturally occuring phenomenon in some bacteria. It is often used as a GENE TRANSFER TECHNIQUE.	Bacterial Transformation
D018274	Electroporation	A technique in which electric pulses, in kilovolts per centimeter and of microsecond-to-millisecond duration, cause a loss of the semipermeability of CELL MEMBRANES, thus leading to ion leakage, escape of metabolites, and increased uptake by cells of drugs, molecular probes, and DNA. Depending on the dosage, the formation of openings in the cell membranes caused by the electric pulses may or may not be reversible.	Electric Field-Mediated Cell Permeabilization,Irreversible Electroporation,Reversible Electroporation,Electropermeabilisation,Electric Field Mediated Cell Permeabilization,Electroporation, Irreversible,Electroporation, Reversible