Lecture 1 +2

Diseases like cholera and malaria were thought to be caused by “ ” or  

Louis Pasteur (1862)
• Proposed that   were responsible for diseases
(…but he had no direct evidence at the time)
• Theory based upon observations he made while
fermenting wine:
o Bacteria + fungal yeasts leads  
o Bacteria is always in  
o Removal of the yeast leads to no fermentation
• He concluded if these microbes can spoil wine, they
likely can also cause  

Robert Koch (1881)
• Developed  (gelatin in a glass Petri dish) to
grow bacterial cultures

Koch demonstrated that demonstrated that a specific disease was caused by a 

Koch's procedures linked  spore in soil to   in cows + human disease. He also dicovered  

Koch's postulates
(1) The microorganism must be found in diseased but not  
(2) The microorganism must be  from the  
(3) Inoculation of a healthy individual with the cultured microorganism must   the disease
(4) The microorganism must be   from the  , diseased individual and matched to the  .

Bacteria are classified as prokaryotes. They have no  . Nucelic acid intemingles with  . Lacks   with membrane bound compartments.

Names are bionomial.   is capitlized and   in lowercase. You can abbreviate   but not  . Both are  

Classify shapes

Spirochetes are different than spirllium because they have an  . Sprillum will  and   will not.

Chains of coccus =  

Clusters of coccus =  

Diplococcus =  

Tetrad =  

Sarcina=  

Most medically important bacteria tend to
express   in the cell wall

Gram   = thick PTG, gram  = thin PTG

Antibotics are more effective against gram   than gram  

Peptidoglycan is a disaccharide of   and 

  captures NAM in the cytoplasmic membrane

  moves NAG and NAM disaccharides from the inner membrane to the outer membrane.

  combines NAG and NAM units

  combines the connected NAG and NAM units to form an even larger structure

TQ
Transpeptidase is also known as   because penicillin prevents the cross-brides from binding

 bacteria are a variation from Gram-positive
and -negative bacteria

Acid-fast bacteria contain a waxy material in the cell
wall (  acid). It prevents  staining.

2 examples of acid fast are expressed by   and  

Acid-fast cells take up an initial stain ( ) while other bacteria decolorize upon alcohol
treatment and then counterstain with methylene blue. They are  . (color)

Smallest known bacteria and agent of atypical
pneumonia is  
•   does not express a cell wall

The tetracyclines (tetracycline, doxycycline, demeclocycline, minocycline, etc.) block bacterial
translation by binding reversibly to the   rRNA in the
 subunit and distorting it in such a way that the
anticodons of the charged tRNAs cannot align properly
with the codons of the mRNA.

Eukaryotes are   (  and  )

Prokaryotes are  (  and  )

Flagella is made of  

One flagella on one end =  
Many flagella all spread put =  
Many flagella all on one end =  

Prokaryotes have   and  

Look at the chart

  viruses stay on surfaces for longer. Causes   infection.

Viruses are   (unstable outside of host cells)

Viruses cannot   proteins without host proteins and enzymes

Genome of virus can be   or   (single- or double-stranded).

Some viruses have envelopes surrounding the structural proteins ( ) and others do
not ( )

Enveloped viruses are suspectible to  

Virus has a narrow range of host
specificity probably because access of the virus to
the host cell is receptor-mediated (viruses
express , to
bind to host receptors for colonization and
infection)

About   of hospital-acquired infections are of fungal
origin

Fungi are eukaryotes but not  

Fungi are  …  (external digestion)

Fungi 2 Morphologies
Two morphologies:
-  and   (  cells)
-  (  cells)

Fungual isease due to   and destruction (few
toxins) as well as damage from the inflammatory immune
response

Fungi cell walls are composed of 3 things
1.   2.   3.  

Cell membranes of fungi are made of   (not  )

Most species of fungi are multicellular composed of   (slender
filament of cytoplasm and nuclei enclosed by a cell wall)

Mass of hyphae make up an individual organism, collectively
called a  

Mycelium can permeate ,   or  

Hyphae of the great majority of disease-causing fungi have
cross-walls called   that separate cytoplasm and nuclei
into cells

Hyphae of some species have incomplete or no septa (i.e. are
aseptate) and thus are  (multinucleated)

Hyphae grow from the   (apical growth)

Yeast
• Single-celled fungi, generally round to  shaped
• They reproduce by   (blastoconidia)

Pseudohyphae
• Hyphae with   constrictions at
septations
• Formed by some yeasts when they elongate but
remain attached to each other

  is notable for developing into
pseudohyphae and true hyphae when it invades
tissues

  are fungal infections.

Most fungi are  …natural habitats being water,
soil and organic debris

Mycoses with highest incidence (part of flora or highly
adapted):
(1)  
(2) 

Most leathal fungus are  . In environment, they growth as   hypae. They are   at room temp and   at body temp

  results when a virulent
microbe (pathogen) invades and
begins growing (colonization)
within a host

  results when, as a
consequence of colonization,
tissue or cellular function is
impaired

Some colonizations do not result in
disease ( ; can
transmit)

Some parasites have evolved to avoid   the hosts in order to
survive and complete their life cycle

Disease is often the consequence of:
(1)  infection
(2)  infection
(3) Unusually   infection

In most cases,   is asymptomatic although
this is not always the case:
(1) Certain parasites kill the host ( )
(2) Parasitic infections of   patients

Protozons disease consequence of of
parasites in large number in host.

Protozoans can be   (plasmodium) or   (giardia)

Transmission of protozans requires a vector and there are two stages: the   and  

Amoebas
 Formless cells that move by  
 “  parasites”
 Alternate between   &  

Flagellates
 Use one or more for motility
 “  &   parasites”
 Usually transmitted by  

Ciliates
 Covered by for locomotion
 Few involved in disease

Apicomplexans (Sporozoa)
 Intracellular replication
 “  &   parasites”
   which scans host cell
surfaces for ligands; and upon engagement,
invasion

Helminths are multicellular animals that are sexually reproductive (usually-some hermaphroditic) are are either   (eggs) or   (live larvae)

Helmiths cannot complete lifecycle without  . Pathology due to l of parasites.

Roundworms (Nematodes)
   in cross section
 Adult worms = 1 – 20 cm
 No visible  (although look
similar to earthworms)

Flatworms
-Asymmetric in cross section
- Two types:
(1) Flukes ( )
(2) Short flatworms w/ nonsegmented
bodies ( )

 mmune system (working with what you got)
 immune system (works against pathognes - Humoral + Cellular immunity)

Microbes often gain access to the
tissues through breaks in the   or
breakdown of the  

Lysozyme
Cleaves   bonds of  

Lactoferrin
Binds sequesters  , limiting growth of  and   disrupts   membrane

  (  and ) distrupt membranes of bacteria, fungi, protozoan, parasites, and viruses additional toaci effects intracellular, kills cells and disables virguses

Should the physical and chemical barriers be breached – innate immune
receptors called   can bind to
the microbe and alert the body to microbe’s presence

PRR bind to conserved microbial components or   (Ex. Toll-like receptor 4)

Some TLRs expressed on the cell
  to detect extracellular microbes

Other TLRs incorporated into the
membranes of and
  to bind to intracellular
microbes

HIGH YIELD

TLR4 =  
TLR 7 =   -inside endosome
TLR9=   -inside endosome

Binding of microbial PAMPs to TLRs
triggers cell signaling leading to
production of tumor necrosis factor
 ,   and
 to promote inflammation

 ) is also released
to block microbial replication (most
effective against viruses)

  receptors
Recogizes viral RNA triggering release of
type I interferons

 receptors
• Recogizes bacterial cell wall components
(peptidoglycan) triggering release of  
and 

 (lyse bacteria)

  (block viral replication)

 (activate endothelial cells for immune cell adhesion and
stimulate immune reactivity of responding cells)

  (recruit activated immune cells to site of infection)

  (digests engulfed microbes within phagocytes

Macrophages can become   or  

Microbial activation of
macrophages leads to M1
polarization resulting in
production of  ,   and
  to promote inflammation

Cytokines and chemokines promote  

 ,   and
  increase vascular permeability

  in tissue produce type 1 interferon (type 1 IFN)

  and  are important for T cells.

TQ
Type 1 interferon
1. Inhibits  
2. does mRNA  
3. Inhibits virus   + 

Complement proteins are synthesized in the  
primarily (  and   as well). They circulate in an  form in the blood.

Complement cells combined covalently to the   and   bound to microbe surface

 (TNF, IL-1) trigger endothelial activation to
capture circulating immune cells

  ligands on leukocutes bind to surface of epithelia. interactions then occur that make the cell flatten out.   then help the cell to "slide" into the tissue

 
• First cells to infiltrate inflamed tissues

Neutrophils contain  ,  and
  which degrades cell membranes,
DNA and RNA

Most granules of neutrophils fuse with the   and
spill out contents into the environment (near the
microbe)

Some granules of neutrophils fuse with the phagosome and spill
contents into it ( 

The two main phagocytes are   and  

Macropgages
-  and   of materials such as
microbes for their clearance and destruction

Lysosome containing digestive enzymes fuses with
the   forming the   process

 from lysosome
spill into the phagolysosome to
degrade microbes

  produces
nitric oxide (NO) and derivatives
which oxidizes DNA bases
generating strand breaks and
mutations preventing DNA
replication and gene expression –
 

 ) and
subsequent enzymes generate
hydroxyl radicals, hydrogen
peroxide and hypochlorous acid
with same action as NO –
 

Natural killer cells have   receptors (expressed by cancer cells and stressed cells) and   receotors (healthy cells- consitutive expression)

NK cells are by default   (active or inactive?)

Healthy cells also express   that binds to inhibitory
receptors = inhibitory signaling overrides activation signaling

Healthy cells constitutively express activation ligands to bind
to   = NK cell defaulted to be
active

Activated NK cells produce
 

IFN-gamma stimulates   to
polarize into  
producing cytokines (IL-12, TNF-
alpha),
phagocytic compounds (ROS),
chemokines (CXCL10, CXCL11), and
presentation molecules to help
activate T cells

Activated macrophages produce  ,  ,   and  

Cytokines can activate NK cells
promoting expansion, expression of
 (aids binding to target cells),
production of   ( )
and increased cytotoxicity against
targets

Acute phase response develops as a
consequence of cytokines ( ,  
and )

  is the primary antibody driving this
response

IL6 increases (1)  (2)   (3)  

Acute phase response leads to
increased phagocytosis by coating
microbes with   as well as
lysis of microbes (complement)

 (DC) are cells that capture
microbes or components and digest them (i.e. antigen
processing) (chew up into little bits and pieces so that they can be displayed)

DC undergo a maturation process as they
migrate to the local  

Antigen (Ag) derived from the microbes
are loaded onto  molecules
and displayed on the  surface

T cells in the lymph node express a  receptor
(TCR) which recognizes  

T cells recognizing Ag are activated – leave the   and migrate through   to site of inflammation