Synthesis of host proteins

The addition of elFs to extracts of EMC-infected cells stimulates the synthesis of host proteins. This is probably due to the effect of eIF-4B. Two possible explanations for the action of... 

About 1.5-2 hours after infection the first viral structural proteins can be detected in cells efficiently infected by SFV (see Kaariainen and S6-derlund, 1978). By 3-4 hours the synthesis of host cell proteins is shut off. The mechanism of host protein shutoff is not yet known, but studies by van Steeg (1982) suggest that it is the viral capsid protein itself which is responsible for the selective inhibition of host protein synthesis. The capsid protein seems to reduce the activity of the initiation factors elF-4B and CAP binding protein below levels necessary for the formation of the 80 S initiation complex from host mRNA. Translation of the viral 26 S RNA is, however, unaffected. More studies are clearly needed to substantiate this interesting possibility. 

Replicative cycles of representative DNA and RNA viruses. A. Replicative cycle of a herpesvirus, an example of a DNA virus. 1. Attachment. 2. Membrane fusion. 3. Release of viral DNA through nuclear pores. 4. Transcription of viral mRNA. 5. Synthesis of viral proteins by host cell s ribosomes. 6. Replication of viral DNA by viral polymerases. 7. Assembly of virus particles. 

The end result of integration is the incorporation of the viral DNA into the DNA of the host cell. Once there, the provirus can serve as a template for the production of mRNA, allowing for the synthesis of viral proteins. These are assembled at the cell membrane to produce new viral particles, which then bud off to seek out new cells to infect. The integrated viral DNA is also necessarily copied whenever the host cell undergoes cell division. The insidious nature of... 

Some E. coli bacteriophages, including f2, MS2, R17, and Qj8, as well as some eukaryotic viruses (including influenza and Sindbis viruses, the latter associated with a form of encephalitis) have RNA genomes. The single-stranded RNA chromosomes of these viruses, which also function as mRNAs for the synthesis of viral proteins, are replicated in the host cell by an RNA-dependent RNA polymerase (RNA replicase). All RNA viruses—with the exception of retroviruses—must encode a protein with RNA-dependent RNA polymerase activity because the host cells do not possess this enzyme. 

The interferons are a family of proteins secreted by animal cells in response to viral and parasitic infections, and are part of the host s defence mechanism. They display multiple activities, affecting the functioning of the immune system, cell proliferation, and cell differentiation, primarily by inducing the synthesis of other proteins. Accordingly, they have potential as antiviral, antiprotozoal, immunomodulatory, and cell growth regulatory agents. 

The introduction of hexahistidine tag (Hise-tag) to the N-terminus of chimeric protein significantly simplify the protein purification procedure, enabling isolation of target protein directly from crude cell extract (Efremenko et al, 2006). There were two main tasks in this work was i) to obtain the genetic construct encoding synthesis of fusion protein N-Hise-X-OPH, where X = superecliptic-pH-sensitive fluorine ii) to reveal conditions (host-strain, temperature and inductor concentration) favorable for construct expression in E.coli cells. 

Within 2 minutes after the injection of T4 phage DNA into an E. coli cell, synthesis of host DNA, RNA, and protein stops and phage mRNA synthesis begins. Phage mRNA codes for the synthesis of capsid proteins and some of the enzymes required for the replication of the viral genome and the assembly of virion components. In addition, other enzymes are synthesized that weaken the host cell s cell wall, so that new phage can be released for new rounds of infection. Approximately 22 minutes after viral DNA (vDNA) is injected, the host cell, now filled with several hundred new virions, lyses. Upon release, the virions attach to nearby bacteria, thus initiating new infections. 

The development of cloning vectors which propagate in eukaryotic hosts, e.g. yeast or cultured animal cells, has in particular eliminated many of the problems associates with the synthesis of eukaryotic proteins. It should be noted that post-translational processing may also vary among different eukaryontes. It is an advantage that shuttle vectors are available that are capable of propagating in both... 

Chloramphenicol exerts its effects by binding to 50S ribosomal subunits and thus inhibiting bacterial protein synthesis by preventing peptide-bond formation, and by inhibiting the synthesis of mitochondrial proteins in the host. The resistance of chloramphenicol stems from the production of chloramphenicol acetyltransferase by microorganisms that metabolize the drug. 

Synthesis of microbial protein from protein and non-protein nitrogen in the diet. The microbial protein is later digested and the amino acids used by the host. 

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