VO 4 microbiology

• Creutzfeldt-Jakob disease (CJD) leads to the destruction of nerve tissue and neurological symptoms.
• Bacteriophage Lambda, Papilloma virus, tobacco mosaic virus, Influenza virus, Adenovirus, Bacteriophage T4, Corona virus are examples of viruses and phages
• Viruses are not living entities and require the machinery of the host cell to replicate
• Viruses are obligate intracellular parasites and infect all organisms on earth
• Viruses are a source for genetic diversity
• Phospholipid bilayer from the host is involved in the attachment of viruses to the host cell
• Comparative genomics shows the genome size of selected viroids, viruses, and prokaryotic cells
• The CRISPR immune system: Clustered regularly interspaced short palindromic repeats.
• Poliovirus causes Poliomyelitis and can lead to flaccid paralysis of the limbs, especially in children.
• The Lytic Human Herpesvirus Life Cycle: Binding, Entry, Release and Nuclear Transport, Nuclear Entry, Gene Expression, DNA Replication, Packaging, Egress.
• Poliovirus belongs to the Picornaviridae family and has positive-sense RNA molecules.
• Most viruses are lytic and very few are known to cause cancer.
• Retroviruses have Gag, Pol, and Env proteins and their lifecycle involves attachment to cell receptors, fusion with the plasma membrane, and trafficking to nuclear pore complexes.
• The Baltimore classification categorizes viral genomes into seven classes based on their composition and replication strategy
• Bacteriophages use different receptors to infect Escherichia coli
• MS2 is a small (+) RNA phage with a genome of 3569 nucleotides and encodes four proteins.
• Cas proteins store pieces of phage DNA as a memory of infection and use these memories to find and destroy matching phage genomes.
• Bacteria have defense systems, such as blocking adsorption, injection, or assembly, cell suicide, or RM systems, to fend off phage infection.
• M13 is a single-stranded DNA phage that uses Escherichia coli as a host for replication.
• φ X174 is a filamentous phage and belongs to the Inoviridae family.
• PAM sequences prevent CRISPR enzymes from cutting the repeat-spacer array.
• CRISPR is an adaptive immune system found in bacteria and archaea that defends against specific types of phages.
• The replication cycle of a lytic bacteriophage involves attachment to the host cell, injection of the viral genome, and replication
• The one-step growth curve is a measure of viral replication
• CI bound to two operator sites recruits RNA polymerase for transcription of cI and the anti-phage defense system.
• The phage lambda-encoded functions and host encoded functions impact the lysis-lysogeny decision and control the lytic gene expression cascade.
• The c I gene product binds to operator sites in the Lambda genome to execute the lysis-lysogeny decision.
• The lysogenic cell can also be induced to form and lyse a mature virus.
• Phi-X174 has been used as a model system for the study of prokaryotic DNA replication, gene expression, and morphogenesis.
• Phi-X174 is a phage with a single-stranded DNA genome that was the first organism to have its whole genome sequenced in 1977.
• The Lambda switch harmonizes multiple signals from the host cell state and infection status to commit to a lytic or lysogenic lifestyle.
• Spanins activate after peptidoglycan degradation and cause fusion of the inner and outer membranes, leading to the release of phage progeny.
• The alternatives after infection by bacteriophage Lambda are replication and release of a mature virus (lysis) or integration of the virus DNA into the host DNA (lysogeny).
• At high concentrations, CI binds a third operator site and inhibits transcription governed by RNA polymerase.
• Virions are exocytosed to complete the life cycle
• Viral RNA enters the cytoplasm and ORF1a or ORF1ab is translated by the host ribosome
• Prion diseases are neurodegenerative disorders caused by misfolded, aggregated proteins known as prions
• Viral RNA and host proteins are packaged into nascent budding particles
• Viral polyproteins are cleaved into NSPs and assemble into replication and transcription complexes
• Progeny virions are assembled in the endoplasmic reticulum and Golgi body