Bacteriophage secretion

Lysozyme is an enzyme that hydrolyzes some bacterial cell-walls, the bacterium used for the assay being Micrococcus lysodeikticus. Lysozyme is found in a wide variety of species and locations, including bacteriophages, blood, egg white, gastric secretions, milk, nasal mucus, papaya, sputum, and tears. The outstanding achievement in this field has been the elucidation of the crystal structures of some of the lysozyme-substrate complexes. 

Infection of E coli with filamentous phage is a chronic one in that the phage does not lyse the E. coli. It is therefore possible to maintain filamentous phage either as a phage-secreting E coli strain or as a suspension of bacteriophage particles... 

Within each host cell system, several independent isolates and laboratory variant strains are available, and the efficiency of expression can vary between them for reasons that are not always understood. For example, there are several independently isolated strains of E. coli, which vary in their ability to express the same protein using the same vector. Thus, it is routine to test several strains for optimal production, and this is usually achieved by screening a bank of available strains. In addition, notably in the E. coli system, there are several mutant strains which may be used to increase product yield and improve fermentation characteristics. Such mutants may have deficiencies in proteases, resulting in increased stability of the expressed protein (Kresze, 1991), cell-wall mutations permitting better secretion characteristics (Le and Trotta, 1991), or resistance to bacteriophages which can lyse bacteria leading to losses and delays in large-scale fermentation. 

Finally, in infections of bacterial and animal cells, virus progeny are released. Especially in animal enveloped V, this can occur continually by cell budding or secretion of the virus, in which the host cell remains intact, and the virus acquires its membrane envelope from the host plasma membrane. Bacteriophages are released by lysis, and therefore death, of the Wt cell. Newly formed plant V. often remain for months or years in their host cells, until they are transferred to a new host by wound contact or by in-... 

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