Biomaterial Database

Electron microscopy of phages liberated by megacin A producing lysogenic Bacillus megaterium strains. 1975

A S Tikhonenko, and N N Belyaeva, and G Ivánovics

Mitomycin C was added at fairly high concentration (5-10 mug/ml) to exponentially growing cultures of selected strains of Bacillus megaterium. Lysis of the bacteria followed, associated by liberation of phage and megacin A production. In contrast, a low concentration (0.5 mug/ml) of mitomycin induced only megacin A production. Electron microscopic examination of the lysates induced by 5-10 mug/ml of mitomycin in 19 strains of B. megaterium showed them all to contain phages; most of the strains proved polylysogenic. Their lysates contained distinct complete phages of different structures and dimensions. A few strains released defective phage particles. The significance of the electron microscopic findings is discussed in relation to megacinogeny.

UI	MeSH Term	Description	Entries
D008242	Lysogeny	The phenomenon by which a temperate phage incorporates itself into the DNA of a bacterial host, establishing a kind of symbiotic relation between PROPHAGE and bacterium which results in the perpetuation of the prophage in all the descendants of the bacterium. Upon induction (VIRUS ACTIVATION) by various agents, such as ultraviolet radiation, the phage is released, which then becomes virulent and lyses the bacterium.	Integration, Prophage,Prophage Integration,Integrations, Prophage,Prophage Integrations
D008530	Megacins	Bacteriocins elaborated by mutant strains of Bacillus megaterium. They are protein or protein-lipopolysaccharide complexes lethal to other strains of the same species.	Megacin,Megacin A
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D008937	Mitomycins	A group of methylazirinopyrroloindolediones obtained from certain Streptomyces strains. They are very toxic antibiotics used as ANTINEOPLASTIC AGENTS in some solid tumors. PORFIROMYCIN and MITOMYCIN are the most useful members of the group.
D009698	Nucleoproteins	Proteins conjugated with nucleic acids.	Nucleoprotein
D003673	Defective Viruses	Viruses which lack a complete genome so that they cannot completely replicate or cannot form a protein coat. Some are host-dependent defectives, meaning they can replicate only in cell systems which provide the particular genetic function which they lack. Others, called SATELLITE VIRUSES, are able to replicate only when their genetic defect is complemented by a helper virus.	Incomplete Viruses,Defective Hybrids,Defective Hybrid,Defective Virus,Hybrid, Defective,Hybrids, Defective,Incomplete Virus,Virus, Defective,Virus, Incomplete,Viruses, Defective,Viruses, Incomplete
D001410	Bacillus megaterium	A species of bacteria whose spores vary from round to elongate. It is a common soil saprophyte.	Bacillus megatherium
D001430	Bacteriocins	Substances elaborated by specific strains of bacteria that are lethal against other strains of the same or related species. They are protein or lipopolysaccharide-protein complexes used in taxonomy studies of bacteria.	Bacteriocin,Lantibiotic,Lantibiotics
D001433	Bacteriolysis	Rupture of bacterial cells due to mechanical force, chemical action, or the lytic growth of BACTERIOPHAGES.	Bacteriolyses
D001435	Bacteriophages	Viruses whose hosts are bacterial cells.	Phages,Bacteriophage,Phage