Class Notes

Class Notes

HSV is spread by contact (close/sexual/maternal) as the virus is shed in saliva, tears, genital and other secretions. Viral proteins target host proteins and either form new complexes or modulate the formation of functional host complexes. Around 10% of population acquires HSV infection through the genital route. Designed to observe larger insects,worms, or plants.Prokaryote Fossils Goes back 3.5 to 4.0Biofilms Microorganisms organized into complex communities of different organisms, growing on a surface.Flora Plant or bacterial lifeProtons Positively charged particles in the atomic nucleusNeutrons Particle in the atomic nucleus that is without electrical charge.Electrons Negatively charged particle orbiting in the shells of atoms. 5. Viruses are the most abundant life form on earth, inhabiting nearly every ecosystem, including animals, plants, and bacteria. CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys.

I love the influenza virus brooch pictured above, but there are many, many other riveting creations. However, several labs would use potential human pathogens (possibly including influenza viruses, La Crosse virus, or others) that are listed as BioSafety Level (BSL) 2 agents. Viral infections in human and animal hosts usually result in an immune response and disease. Single Stranded (+) Sense DNA 3. viruses cannot be isolated as “colonies” the reason is that although viruses can be obtained at incredibly high concentrations, they disperse in suspension. Class IV viruses have positive-sense ssRNA which is copied to a negative-sense ssRNA genome prior to mRNA synthesis. Their nucleic acids have substantially distinct nucleotide sequences from either their helper virus or host.

3. The DNA then moves into the nucleus where it can express genes and replicate. More recently, molecular analysis of viral replicative cycles has further refined their classification. An icosahedron is a regular polyhedron with twenty facets, twelve vertices, and a 5:3:2 symmetry (fifteen potential bilateral symmetry axes, ten potential trilateral symmetry axes, and six potential pentalateral symmetry axes). Viral genome content is one of the main discriminators for virus classification (26, 38). VirusMINT only offered data curated by the MINT curation team. VZV is in Group I of the Baltimore Classification because it is a dsDNA virus that does not use reverse transcriptase.

Glycoproteins embedded in the viral envelope are used to attach to host cells. Capsomrs are made up of structural units, individual protein molecules. To circumvent,these viruses contain enzyme in the virion,enters cell along with the genomic RNA. CPE can include apoptosis, syncytium formation (fusion of infected cells), inclusion body production, and transformation (loss of contact inhibition and piling up of cells in concentrated foci). PMID 13931895. 29 RNA Virus Families Several general features are evident from the classification:  None of the dsRNA viruses are enveloped. Hemagglutination assay: many viruses have glycoproteins (such as hemagglutinin) on their surface capable of binding erythrocytes.

There is a smaller risk from recurrent lesions in the mother, probably due to the lower viral load and the presence of specific antibody. Molecular interaction evidence is reported in the scientific literature in natural language format, thus making retrieval and processing a difficult task (12,13). Almost all cases occur due to direct contact with infected maternal secretions although some cases are due to postnatal transmission. To assay, make multiple dilutions of virus and look for the effect. Titer is the reciprocal of the dilution producing an effect on fifty percent of test subjects (cells). Nucleic acid–based recognition can sense either virion-associated viral genomes (replication independent) or replication products, including the whole genome, replication intermediates, or viral transcripts. In pharmacology, bioavailability is used to describe the fraction of an administered dose of unchanged drug that reaches the systemic circulation, one of the principal pharmacokinetic properties of drugs.

A dilution of viruses is added to cells and overlaid with semi-solid medium. Since viruses cannot move through the medium, patches of virus-infected cells (plaques) form, each plaque arising from a single infectious unit. In taxonomy, the classification of viruses is difficult owing to the lack of a fossil record and the dispute over whether they are living or non-living.[24][25] They do not fit easily into any of the domains of biological classification, and classification begins at the family rank. El Mortata, Mohammed, MaryAnn Tran, Corrine Young, Mary D. inserts its (+) strand RNA into the cell. Stages of Reproduction At attachment, the virus binds to a cellular molecule (receptor) by a protein on its own surface (the anti-receptor). In penetration, a virus can enter the cell by one of three mechanisms: Translocation of the viral nucleocapsid across the plasma membrane Endocytosis of the virus into endosomes Fusion of the viral envelope with the cell plasma membrane.

Virus diseases are skewed towards children, as the immune system is immature, and children dont have good hygeine. There are over one hundreds types of human papillomavirus that can cause infections to human. Animal viruses, such as HIV, are frequently enveloped. The first mRNAs produced encode the so-called “early” proteins, which are needed for successful viral replication, such as viral enzymes involved in DNA synthesis and proteins which alter cellular metabolism and defenses. The pellets were resuspended in 1× PBS and stored at −20°C for further use. The key information to identify redundancy are supported by every database of the IMEx consortium, i.e. Positive-Sense RNA Viruses Most RNA viruses replicate in the cytoplasm.
Class Notes

The viral genome is, in effect, a polycistronic mRNA. Two methods of dealing with the polycistron are production of subgenomic mRNAs by a viral polymerase, or production of a large polyprotein which is post-translationally cleaved into individual viral proteins. Viral polymerase makes a full-length negative-sense copy of the genome (anti-genomic RNA), which acts as a template for production of new negative-sense genomic RNA. Negative-Sense RNA Viruses Viral genome cannot act as its own template, so a viral RNA-dependent RNA polymerase must be carried in the virion along with the viral genome. Replicate in either the cytoplasm or nucleus. The polycistron is solved in several ways: Production of subgenomic mRNAs by a polymerase which terminates and re-initiates between genes. Division of the genome into multiple segments, each encoding only one gene (so each segment is monocistronic).

However microscopy cannot distinguish between different herpes viruses. The mapping procedure is illustrated in Figure . FITC is generally used for staining, its 90% sensitive and 90% specific than light and electron microscopy, however expertise is more demanding. Capsid proteins may assemble around the genome, or the genome may be translocated into empty capsids. Post-translational events are usually required to make newly-assembled virions active, either by host factor action (endogenous enzymes) or virus-encoded factors (such as HIV nucleocapsid condensation by viral protease). Recent data indicate that TLR3-deficient mice succumb to central nervous system infection upon vaginal HSV-2 challenge due to a lack of type I IFN production by astrocytes (80), revealing the importance of innate recognition of HSV by TLR3 in the brain. Antiviral drugs are a class of medication used specifically for treating viral infections.

Non-enveloped viruses are released by cell lysis. Problems with Replication Formation of non-infectious particles often occurs. A medium-sized virion next to a flea is roughly equivalent to a human next to a mountain twice the size of Mount Everest. “Herpes Viruses.” Herpes Viruses. While DNA-DNA replication results in one mistake per 109! to 10!10 bases, RNA-RNA replication results in one mistake per thousand or ten-thousand bases. No proofreading function exists in RNA polymerase.

Because of this, multiple mutations will be present in each virus genome, resulting in an RNA virus population existing of slightly-different clones, or quasispecies, which together make up a consensus sequence. These 4 types of HPV account for 90% of cervical cancer (Frey 2010). Group IV viruses have ssRNA as their genome with a positive polarity. Icosahedral nucleocapsid Envelope acquired from cell membrane or Golgi apparatus. (viii) Fifty percent formamide in a DEPC-PBS-saturated humid chamber was added. The user can select the proteins of interest by adding them to the ‘protein bag’. Upon entry into the nucleus, the linear genome circularizes and begins producing α-mRNA (the “early” genes).

α proteins re-entering the nucleus induce β-mRNA production. β proteins re-entering the nucleus induce γ-mRNA production and genome replication (as linear copies). γ proteins then assemble into the nucleocapsid and promote packaging of genome, as well as producing transmembrane proteins which allow enveloping and budding from the cell. An 8kb, linear, positive-sense, ssRNA genome Icosahedral nucleocapsid without envelope Binds to CD155, or poliovirus receptor (PVR) without the need for a coreceptor. Penetration and uncoating results by release of the viral genome from the extracellular capsid due to a conformational change caused by receptor binding. Poliovirus contains it own polymerase. The poliovirus polyprotein has intrinsic protease activity which catalyzes its own cleavage into eleven separate proteins by three rounds of cleavage.

Serology – presence of VZV IgG is indicative of past infection and immunity. Each gene is accompanied with essential information extracted from UniProt including the … Acyclovir is given promptly to immunocompromised individuals with varicella infection. Modified icosahedral-conical symmetry. Envelope acquired from host plasma membrane. Unlike RIG-I, MDA5 does not recognize 5′-ppp RNA. In general usage, alcohol (from Arabic al-khwl الكحول, or al-ghawl الغول) refers almost always to ethanol, also known as grain alcohol, and often to any beverage that contains ethanol (see alcoholic beverage).

Partial uncoating occurs on entry, and final uncoating in the nucleus. The genome is made up of gag, pol, and env segments. Both types are susceptible to antiviral drugs that inhibit the reverse transcriptase enzyme, e.g. pol is the reverse-transcriptase and polymerase proteins env is structural and envelope proteins. Reverse-transcriptase converts the genome to a proviral dsDNA form, which can insert into host cell genomes. The HIV replication cycle involves release of the capsid into the cytosol by membrane-envelope binding and fusion. Partial uncoating occurs as reverse transcription of the genome creates a proviral DNA.

Full uncoating occurs in the nucleus, where integrase inserts proviral DNA into the host genome. Viral proteins and two copies of the viral genome are created for each virus and incorporated into a budding envelope. Capsid condensation by HIV protease within the sealed envelope. 13kB linear ssRNA genome in eight segments, in a helical nucleocapsid Envelope derived from plasma membrane Binds sialic acid on host glycoproteins without the aid of coreceptors Penetrates by receptor-mediated endocytosis Uncoating induced by low pH in endosomes, causing fusion of envelope with the endosome membrane. Bulge-Loop RT-PCR and probe-specific TaqMan RT-PCR.Two μg RNA extracted from KSHV particles was first reverse transcribed by ReverTra Ace (Toyobo, Osaka, Japan) according to manufacturer’s instructions. Upon release, the virus binds to the original host cell. It is freed by action of NA, which releases the virus from the surface of the original host cell.

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