Lecture 1 Flashcards
What are the 6 infectious microorganisms?
-HIV
-Influenza
-STAPHYLOCOCCUSAUREUS
-STREPTOCOCCUSPNEUMONIAE
-SALMONELLAENTERITIDIS
-MYCOBACTERIUM TUBERCULOSIS
What are the sizes of microorganisms?
-Viruses (0.03-0.3uM)
-Bacteria (0.1-10uM)
-Microscopic protozoa and fungi (4-10uM)
Naked Viruses contains what?
Capsid & Nucleic acid
Enveloped Viruses contain what?
-Envelope
-Spike
-Capsid
-Nucleic acid
T/F: Viruses are not cells
True
Slide 13 review differences between prokaryotes and eukaryotes
T/F: Bacteria are prokaryotes
True
Fungi and parasites are what?
eukaryotic organisms represented by single-cell and complex organisms
Sources and Sites of Infection
-Direct vs Indirect (contact)
-Horizontal vs Vertical (mother to fetus)
Slide 17 memorize
What are the classes of microorganisms?
Microbiome (normal flora)
Commensal (resident, symbiotic, core microbiome)
Transient colonization (transients, secondary microbiome)
Opportunistic (carrier state)
Pathogenic
Commensal Microorganisms ??
Endogenous flora
> 1000 species in the human body; billions of organisms
Microbiota – cohorts of microbes in specific body regions
Provide many benefits
Process digested food
Provide essential vitamins/growth factors
Protect against invasion of pathogens
In a constant state of flux dependent on age, diet, health
Microbial populations change in response to illness or treatment with antibiotics (dysbiosis)
What are Virulence?
Circumstances that allow a microorganism to achieve infection and cause disease with varying degrees of severity
Virulence factors are…
gaining access to the body
avoiding multiple host defenses
colonization of the host
parasitizing host resources
inducing toxicity and damage
Influences on the Microbiome
-Host physiology
-Environement
-Immune System
-Host genotype
-Lifestyle
-Pathobiology
Human Microbiome Project is
Effort to sample and analyze the genome of microbes from five sites on the human body
Nose
Oral cavity
Skin
Gastrointestinal tract
Urogenital tract
Viral Classification
All viruses are intracellular pathogens
All viruses must use some components of the hosts cellular biosynthetic machinery
All viruses are nucleic acid based
All viruses replicate by assembly of components
All viruses are composed of the viral genome, a protective coat & associated enzymes/proteins
All viruses are composed of
the viral genome, a protective coat & associated enzymes/proteins
Nucleic Acids consist of
DNA or RNA
single or double stranded
linear or circular
continuous or segmented genome
Outer layer consist of
capsid (naked)
envelope
VAPs (viral attachment proteins)
Capsid shape
spherical
icosahedral (icosadeltahedral)
filamentous
brick-shaped
bullet-shaped
+RNA
(N)-Picorna Calici
(E)-Toga Flavi Corona
-RNA
(E)- Rhabdo Filo Orthomyxo Paramyxo Bunya Arena
+/-RNA
(Double Capsid)- Reo
+RNA via DNA
(E) Retro
slide 45
Enveloped
Pox Herpes Hepadna
Naked Capsid
Polyoma Papilloma Adeno Parvo(ss)
Slide 48
Viral Replication steps
1) Recognize target cell
2) Attachment
3) Penetration/Fusion
4) Uncoating of virion
5) Transcription
6) Protein synthesis
7) Replication
8) Assembly
9) Release
Viruses can be
-Productive: Lyse the infected cell (lytic response)
Non-productive
Lysogenic– integration of viral genome into host genome or formation of extrachromosomal plasmid
Oncogenic transformation
Persistent – latent or chronic
Cells can be
Permissive
Allow viral replication or integration
Non-permissive
Do not allow replication but may be transformative
Abortive – no replication but cause cell death
Target recognition & attachment
VAPs, host range, tissue tropism
Penetration
receptor-mediated endocytosis (viropexis), membrane fusion
Uncoating
remove coat, deliver to site of replication
Synthesis
early gene products – non-structural proteins, replication
late gene products – structural proteins
T/F: Most DNA Viruses generate mRNA thru splicing
TRUE
From the same DNA, many different mRNA transcripts are translated into proteins
Segmented RNA genomes
one segment encodes one proteins
Some viruses have one long RNA(-) genomic strand from which mRNA can be directly transcribed
just know this
Protein synthesis
requires host ribosomes, tRNA & post-translational machinery
At Ribosomes:
produce giant, genome-spanning
polyprotein
produce smaller polypeptides
produce individual proteins
achieve preferential translation by
block mRNAs
degrade host DNA & mRNA
decrease cellular transcript access/concentration
Assembly
recognition sequences allow protein:protein, protein:nucleic acid and protein:membrane interactions
for budding, viral membrane proteins (like spike proteins) inserted into plasma membrane
Release
bud from plasma membrane
bud through ER/Golgi (remain intracellular)
pass through ER & transported to surface (endosomes)
cell lysis
cell-cell bridge
DNA viruses do what?
Uses the host cell DNA-dependent, RNA polymerase to make mRNA
Uses freshly made DNA-dependent, DNA polymerase to copy DNA
(+) RNA VIRUSES do what?
(+)RNA viruses can begin translation by ribosomes as soon as the genome is uncoated
Will still encode for a viral polymerase to copy the genome for replication (RNA-dependent, RNA polymerase)
(-) RNA VIRUSES
(-)RNA viruses must carry a viral RNA-dependent, RNA polymerase to transcribe the negative strand into mRNA
L PROTEIN
Viral genetics are
Parental (wild-type)
Mutants (change in coding sequences)
viruses have terrible polymerases; lots of errors
Lethal mutations
Deletion mutants
Plaque mutants
Host range mutants
Attenuated mutants
Conditional mutants
Antigenic Drift
Codon should be UUU translated to AAA (Lysine); mutation created CUU which is translated to GAA (Glutamic acid
