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Micro 121 > Viruses and fungi > Flashcards

Viruses and fungi Flashcards

(66 cards)

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1
Q

Gram - Cell Envelope

A

outer membrane
cell wall
periplasmic space
cell membrane

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2
Q

cell membrane

and functions

A

phospholipid layer

active transport and energy production.

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3
Q

cell wall

A

peptidoglycan crosslinked meshwork

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4
Q

peptidoglycan layer made up of

A

N-acetylglucosamine (NAG)
N-acetylmuramic acid (NAM)
Amino Acids
= building blocks added to growing polypeptide chain

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5
Q

cell wall functions

A

osmotic barrier
antibiotic site of action
provides shape: rod, coccus, spiral

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6
Q

outer membrane

A

lipopolysaccharide (Endotoxin)

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7
Q

functions of outer membrane

A 
permeability barrier (porin proteins)
sometimes bacteria will change these proteins(PBP)
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8
Q

Virus

A

Obligate intracellular parasite

Cannot make energy, completely dependent on host cell

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9
Q

virus structure

A

Noncellular
no organelles
no ribosomes

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10
Q

Virus structure (made up of)

A

genome (made of DNA or RNA)
capsid (protein shell)
envelope - only some have this.

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11
Q

envelopes have

A

spikes containing glycoprotein/lipid

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12
Q

Virus capsid

A

Protein shell that provides shape
assembly of identical protein subunits
ex. icosahedral

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13
Q

Virus replication cycle

A 
attachment
enter and uncoating
replication 
assembly
release
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14
Q

attachment

A

susceptible cell: receptors (glycoprotein) for the cirus on the cell surface
Specific distribution to specific tissues

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15
Q

spikes (attachment)

A

recognize CD4 receptors on the host cell

ex. on WBC for HIV

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16
Q

Viral entry (3)

A
  1. Endocytosis
  2. Direct fusion
  3. Nucleic acid translocation
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17
Q

endocytosis

A

Majority of nonenveloped viruses

entire virus engulfed by teh cell and enclosed in a vacuole

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18
Q

direct fusion

A

Enveloped viruses
Envelope fuses with the cell membrane of host cell with spikes trapped in membrane
protein capsi transferred into the cell (protein and nucleic acids inside cell)

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19
Q

nucleic acid translocation

A

Rare nonenveloped viruses
Capsid adheres to host cell membrane -> partial rearrangement of virion -> nucleic acid (only) passes directly into host cell

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20
Q

dsDNA Replication

A

Virus uses host RNA Polymerase to make RNA: capsid proteins and DNA polymerase
Virus uses the created DNA polymerase to replicate DNA

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21
Q

RNA Replication (2)

A

some can act directly on the ribosome

retroviruses

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22
Q

(+) RNA Virus (Retroviruses)

A

not used directly as mRNA
Uses own virion reverse transcriptase to make dsDNA -> integrated into the host cell’s chromosome
integrated dsDNA transcribed with normal cell machinery ->mRNA)

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23
Q

reverse transcriptase enz process

A

creates ssDNA complementary to the retroviral RNA

  • > ssDNA -> complementary DNA
  • > dsDNA enters host cell nucleus
  • > Latent infection
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24
Q

latent viral infections

A

the persistence of viral genomes

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25
latent viral infection ex's
herpes simplex and varicella - latent infection in sensory neurons HIV-1latent infection of resting memory CD4 (+) T cells.
26
nonenveloped viruses assembly and release
lysis - kill
27
enveloped viruses assembly and release
Bud through the host cell plasma membrane - slower killing of the host once enough of the embrane is gone.
28
Diagnostic detection of viruses (5)
``` direct detection with microscopy Viral culture Serology Amplification of the nucleic acid Antigen detection ```
29
direct detection with microscopy of viruses
for viruses that are very difficult to grow rarely done, time consuming - look at the shape electron microschope used - impractical
30
Viral culture
Many different tissue types are inoculated if there is a virus - monolayer of cells will be destroyed be aware of cytopathic effect (CPE)
31
Cytopathic effect
nonspecific viral culture Effect the virus infection has on the appearance of cell in culture viewed by light microschope after pt specimen is inoculated onto the cell culture and the virus has replicated can't tell which virus it is, just that there is a virus
32
Serology
detection of the immune response by the host against the infecting agent Detecting specific immunoglobulin (antibody)- need to know what you are looking for very common way of detecting viruses ex. Hep B
33
PCR
specfici segment of RNA or DNA genetic material extracted from pt sample. genetic matieral is multiplied many times and then detected extremely sensitive and specific becoming the standard
34
antigen detection:
derect ttest on a patient specimen | detect specific antigen of the particular organism you are looking for.
35
example of antigen detection
in kids with rotavirus | stool contains the antibody binded to the antigen - can detect it
36
Antiviral agents
Viral uncoating (penetration): stop virus from being uncoated = neutral virus nucleic acid synthesis: reverse transcriptase inhibitors (HIV) Assembly and Release: Protease inhibitors (HIV) - Flu.
37
Eukaryotic cell structure
Cytoplasmic membrane | Cell wall
38
Fungal cytoplasmic membrane made of
ergosterol (primary sterol)
39
Cell wall made of
Chitin (No peptidoglycan)
40
reproduction of funi
Spores or Canidia
41
charachteristics of the spore that is used to classify the fungi
size shape arrangement`
42
growing yeast on and in this much time
bacteriology or mycology media | 24-48 hours.
43
Yeast in comparison with bacteria
budding cells | larger
44
gram stain on yeast
will work but call them purple cells
45
mold growth
through the development of hyphae: multicellular fungal elements
46
hyphae grow to
mycelium enough hyphae to be visible ex. green stuff in the cheese
47
meningitis
``` yeast infection (cryptococcus neoformans) - affects the lining of the brain yest with large capsule (pathogenicity factor) ```
48
2 types of hyphae
reproductive hyphae - not seen in the host branches vegetative hyphae - seen in the host roots
49
Growing of molds
most from environment specific media with antibiotics to inhibit bacteria and support fungi optimize environmental conditions lower temp 30 degrees Takes weeks. ORDER FUNGUS CULTURE SPECIFICALLY
50
Dimorphic Fungi
grow depending on temperature yeast at 37 mold at 30
51
histoplasma capsulatum
follow bird migration and great lakes - damp soils | resp infection
52
blastomyces dermatitidis
Follow bird migration and great lakes | cause blastomycosis
53
coccidioides immitis
North America Causes coccidioidomycosis (valley fever) creates lung tumor - need lung biopsy.
54
all the Fungi infections start with
respiratory infections by breathing them in.
55
Target sites for antifungal therapy
cell wall: inhibit chitin cell membrane - inhibit ergesterol mitosis
56
cell membrane tartgeted antifungals
Polyenes - Ergosterol incorporation - very costly, IV, for serious diseases azoles: Ergosterol synthesis: - more common, treat serious, oral and IV
57
How do you get fungal disease (2)
Change in host | environmental exposure
58
change in hist (2)
antibiotics: - also kills off some normal flora therefore, susceptible to fungal infection immunosupression a. neutropenia - susceptible to aspergillus b. T cell destruction (AIDS) - susceptible to histoplasma
59
Environmental superficial infections
dermatophytes | Ringworm
60
ringworm can only infect
skin hair nails because of keratin as growth substrate
61
disease state of dermatophytes is called
TInea
62
to get dermatophitic infection you need
prolonged direct contact - hyphae can get to the next person and survive.
63
Molds names to recognize
Epidermophyton Trichophyton Microsporum
64
yeast name
Candida
65
Factors affecting systemic infection (systemic mycoses)
route of exposure (aerosol) previous exposure/immunity status of immune system amount of inoculum
66
detection of fungi
``` culture (Y-1-3 day, dermatophytes (1-3wks, systemics (3-6wks) Direct smears KOH Mount Calcoluor Gram Stain Silver Stain. ```

Micro 121 (3 decks)

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