Viruses 2 phage

Poliomyelitis virus Equine encephalitis virus Influenza virus Phage T3... 

For microbiology measurements, calibration is not performed as such. In fact the analyst often counts colonies (bacteria) or plaques (holes) in cultures (viruses, phages) or positive tubes (most probable number techniques) which are supposed to be issued from one single biological particle. The growth of the particle depends on the medium in which this growth is done. 

Yet another solution to this problem is used by some viruses. Phage < )29 of Bacillus subtilis primes the replication of its 19,285 bp dsDNA at both ends by a terminal protein, which is linked covalently through its Ser 232 - OH group to dAMP. The 3 -OH of the deoxyadenosyl group primes the DNA replication. In a similar fashion replication of the eukaryotic adenoviruses, whose genome is a 35- to... 

Explanations to the Figures, b, c A Fusogenic Virus (Phage) of Acholeplasma laidlawii. Possible Evolutionary Consequences. 

Finally, if the trait to be altered needs to be measured outside of the cell, like the binding of a ligand, then there are several methods available to physically link the expressed mutant proteins to their mutant DNA sequences. This can be accomplished using display techniques, where the mutant proteins are displayed on the surface of a DNA carrying vehicle, such as a virus (phages), bacteria, yeast, mammalian cell, ribosome, and even the plasmid DNA itself These methods are very amenable to a selection protocol, and then the attached vehicle can be used to retrieve the DNA sequence of the displayed proteins. 

Since all members of this family of RNA phages have homologous coat proteins, their subunits are expected to have the same three-dimensional structure. It remains to be seen if the MS2 fold is also present in any other unrelated viruses. The fold is so far unique for the MS2 subunit, but similar structures have been observed in other proteins such as the major histocompatibility antigen, HLA, which was discussed in Chapter 15. 

Viruses are discussed more fully elsewhere (Chapter 3). However, there are certain groups of viruses, called bacteriophages (phages), which can attack bacteria. This attack involves the injechon of viral DNA into baeterial eells which then proceed to make new virus particles and destroy eells. Some viruses, known as temperate viruses, do not cause this catastrophic event when they infect their host, but can pass genetic material from one cell to another. 

Viruses are classified initially on the basis of the hosts they infect. Thus we have animal viruses, plant viruses, and bacterial viruses. Bacterial viruses, sometimes called bacteriophages (or phage for short, from the Greek phago meaning to eat), have been studied primarily as convenient model systems for research on the molecular biology and genetics of virus reproduction. Many of the basic concepts of... 

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