Biomaterial Database

Rhizobium meliloti carries two megaplasmids. 1985

Z Banfalvi, and E Kondorosi, and A Kondorosi

In Rhizobium meliloti strain 41 the existence of a second megaplasmid (pRme41c) with a molecular weight similar to the sym megaplasmid pRme41b was demonstrated. Derivatives of the wild-type strain carrying pRme41b or pRme41c tagged with Tn5 allowed the examination of the transfer ability of both megaplasmids. The introduction of megaplasmids into the wild-type R. meliloti was not detected, probably because of the action of plasmid genes coding for entry exclusion of the same type of plasmid. However, transmissibility of both megaplasmids was observed in matings with Nod- or Fix- pRme41b deletion mutant recipients and with Agrobacterium tumefaciens at frequencies of 10(-6) - 10(-8). Introduction of the megaplasmids into the R. meliloti recipients resulted in the loss of the same plasmid. On the other hand, pRme41b and pRme41c were compatible. From the extent of deletions in various Nod- and Fix- mutants a DNA region carrying genes probably involved in "surface exclusion" on pRme41b was located. This DNA region is about 50 kb distant from the nod genes and exhibits strong homology with a DNA segment of pRme41c. Symbiotic genes on pRme41c were not identified.

UI	MeSH Term	Description	Entries
D009693	Nucleic Acid Hybridization	Widely used technique which exploits the ability of complementary sequences in single-stranded DNAs or RNAs to pair with each other to form a double helix. Hybridization can take place between two complimentary DNA sequences, between a single-stranded DNA and a complementary RNA, or between two RNA sequences. The technique is used to detect and isolate specific sequences, measure homology, or define other characteristics of one or both strands. (Kendrew, Encyclopedia of Molecular Biology, 1994, p503)	Genomic Hybridization,Acid Hybridization, Nucleic,Acid Hybridizations, Nucleic,Genomic Hybridizations,Hybridization, Genomic,Hybridization, Nucleic Acid,Hybridizations, Genomic,Hybridizations, Nucleic Acid,Nucleic Acid Hybridizations
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
D002874	Chromosome Mapping	Any method used for determining the location of and relative distances between genes on a chromosome.	Gene Mapping,Linkage Mapping,Genome Mapping,Chromosome Mappings,Gene Mappings,Genome Mappings,Linkage Mappings,Mapping, Chromosome,Mapping, Gene,Mapping, Genome,Mapping, Linkage,Mappings, Chromosome,Mappings, Gene,Mappings, Genome,Mappings, Linkage
D003001	Cloning, Molecular	The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.	Molecular Cloning
D003227	Conjugation, Genetic	A parasexual process in BACTERIA; ALGAE; FUNGI; and ciliate EUKARYOTA for achieving exchange of chromosome material during fusion of two cells. In bacteria, this is a uni-directional transfer of genetic material; in protozoa it is a bi-directional exchange. In algae and fungi, it is a form of sexual reproduction, with the union of male and female gametes.	Bacterial Conjugation,Conjugation, Bacterial,Genetic Conjugation
D004251	DNA Transposable Elements	Discrete segments of DNA which can excise and reintegrate to another site in the genome. Most are inactive, i.e., have not been found to exist outside the integrated state. DNA transposable elements include bacterial IS (insertion sequence) elements, Tn elements, the maize controlling elements Ac and Ds, Drosophila P, gypsy, and pogo elements, the human Tigger elements and the Tc and mariner elements which are found throughout the animal kingdom.	DNA Insertion Elements,DNA Transposons,IS Elements,Insertion Sequence Elements,Tn Elements,Transposable Elements,Elements, Insertion Sequence,Sequence Elements, Insertion,DNA Insertion Element,DNA Transposable Element,DNA Transposon,Element, DNA Insertion,Element, DNA Transposable,Element, IS,Element, Insertion Sequence,Element, Tn,Element, Transposable,Elements, DNA Insertion,Elements, DNA Transposable,Elements, IS,Elements, Tn,Elements, Transposable,IS Element,Insertion Element, DNA,Insertion Elements, DNA,Insertion Sequence Element,Sequence Element, Insertion,Tn Element,Transposable Element,Transposable Element, DNA,Transposable Elements, DNA,Transposon, DNA,Transposons, DNA
D004262	DNA Restriction Enzymes	Enzymes that are part of the restriction-modification systems. They catalyze the endonucleolytic cleavage of DNA sequences which lack the species-specific methylation pattern in the host cell's DNA. Cleavage yields random or specific double-stranded fragments with terminal 5'-phosphates. The function of restriction enzymes is to destroy any foreign DNA that invades the host cell. Most have been studied in bacterial systems, but a few have been found in eukaryotic organisms. They are also used as tools for the systematic dissection and mapping of chromosomes, in the determination of base sequences of DNAs, and have made it possible to splice and recombine genes from one organism into the genome of another. EC 3.21.1.	Restriction Endonucleases,DNA Restriction Enzyme,Restriction Endonuclease,Endonuclease, Restriction,Endonucleases, Restriction,Enzymes, DNA Restriction,Restriction Enzyme, DNA,Restriction Enzymes, DNA
D004269	DNA, Bacterial	Deoxyribonucleic acid that makes up the genetic material of bacteria.	Bacterial DNA
D004352	Drug Resistance, Microbial	The ability of microorganisms, especially bacteria, to resist or to become tolerant to chemotherapeutic agents, antimicrobial agents, or antibiotics. This resistance may be acquired through gene mutation or foreign DNA in transmissible plasmids (R FACTORS).	Antibiotic Resistance,Antibiotic Resistance, Microbial,Antimicrobial Resistance, Drug,Antimicrobial Drug Resistance,Antimicrobial Drug Resistances,Antimicrobial Resistances, Drug,Drug Antimicrobial Resistance,Drug Antimicrobial Resistances,Drug Resistances, Microbial,Resistance, Antibiotic,Resistance, Drug Antimicrobial,Resistances, Drug Antimicrobial
D005798	Genes, Bacterial	The functional hereditary units of BACTERIA.	Bacterial Gene,Bacterial Genes,Gene, Bacterial