MICRO Exam 2 Lecture 12

10% chlorine bleach solution

What is best for sterilziing tattoo needles?

a. ethanol 70%

b. tincture of iodine

c. soap and water

d. 10% chlorine bleach solution 

concentration, microbial susceptibility, temp and ph, environment, endospore formers

chemical agents are important to lab safety so what are things to consider?

virus

non-cellular infectious particle

requires a host cell

lack metabolism

no

is a virus living thing

virion

complete, infectious viral particle

capsid

viruses have a protein coat that protects the genome

made of capsomer protein

composed of protein units

enveloped viruses

viruses with a lipid membrane

naked viruses

viruses with no membrane

viral attachment proteins (VAP)

mediate the interaction of the virus with the target cell

disruption of these prevents infection

envelope lipids

only occurs if host cell is not covered by cell wall

come from host

envelope proteins

virus embeds viral protein in envelope

important for virus to recognize host cell

naked capsid

reistant to drying, acid, and detergents

resistant to acid and bile of digestive system

transmitted by fecal-oral route and fomites

endure transmission in sewage

envelope

can be maintained in aqueous solutions only

disrupted by drying conditions, detergents, and solvents

must remain wet

transmitted in fluids, respiratory droplets, blood and tissue

matrix proteins

found in enveloped viruses 

important for assembly of enveloped virions

viral attachment protein (VAP)

a virus attaches to a cell based on a __ binding to cellular receptor

often referred to as the spike protein 

interaction with a cellular receptor is specific 

icosahedral capdis

20 triangular sides

each triangle made up of at least 3 identical capsid proteins 

allows small protein to cover a large volume

many human and animal viruses 

may be enveloped or naked

ex: herpes, HPV

filamentous/helical capsids

long tube of protein with genome inside

tube made up of hundreds of identical protein subunits arranged in a helical symmetry around genome

tube length reflects size of viral genome

some viruses with these capsids have multiple genome segments

may be enveloped or naked

ex: ebola, tobacco mosaic virus, measles

complex capdis

mix of icosahedral and filamentous symmetry

many bacteriophages (virus that infects bacteria)

T4

asymmetrical (irregular) capsids

viral capsid protein are arranged without symmetry

tend to be large viruses

poxviruses

ex: cow pox, smal pox

genome

DNA or RNA, reverse transcription, single or double-stranded genome, circular, or linear

morphology

presence of envelope, shape, size, number of capsomers, surface structure

epidemiology

geographic distrubition, seasonal spread, targeted age groups, type of transmission

pathology

hepatitis, respiratory viruses, systemic; type of damage to host cells

antigenic properties

neutralization by certain antibodies - viral typing/subtyping

sensitivity to various agents

UV light, chlorine, ether, formaldehyde, detergents

syndromes

sets of physucal signs and symptoms that occur together

permissive cell

a host cell that supports the complete replication cycle of a virus

recognition, attachment, penetration, unocoating, macromolecular synthesis, assembly, release

steps in life cycle

recognition and attachment

attachment of the virus to the host cell through specific interaction

penetration

viral entry into the cell via fusion of envelope to the lasma membrane, endocytosis, or direct injection (bacteriophages)

uncoating

disassembly and localization

nucleocapsid must be delivered to site of replication

removal or degradation of capsid to release genome into host cell

can occur at cell surface or within the cytoplasm

may be coupled with penetration

transcription of virus genetic material, viral protein synthesis, replication of virus genome

three events critical to viral infection

early proteins

usually regulatory proteins’for RNA viruses, __ are usually vital enzumes

polymerases

late proteins

mRNA is translated into structural proteins, which will form the capsid

eclipse

the period in which the virus copies its genome and produces proteins

maturation

assembly of viral particle assembling the capsid around the genome, incorporating any other required protein

burst size

number of virions released

lytic infection

release of virus and death of host cell

latent infection

presence of virus without active replication

persistent infection

slow virus release without killing the host cell

transformation

cell is converted into tumor cell (uncontrolled growth of host cell)

mechanism of exposure and site of infection, immune status, age, general health, viral dose, genetics of virus and host

susceptibility and severity of disease depends on: