Compared to eucaryotic cells

(human cells)

prokaryotic cells are...

• of very ancient origin (survivors, ↑danger to humans)
  
• smaller (↑ability to hide from immune system)
• simpler (↑survival, ↓energy requirement, take less to repair)
• more abundant

(continued)

Compared to eucaryotic cells

(human cells)

prokaryotic cells are...

have no nucleus

(DNA unprotected in cytoplasm~BUT~we can't attack w/abx all the time since human DNA also targeted)
have no organelles

(Activities hard to target since all happens within cytoplasm)
have a single chromosome

(vs- human's 46 chromosomes)

(continued)

Compared to eucaryotic cells

(human cells)

prokaryotic cells are...

Much more sophisticated in terms of:

~ adaptation capabilities

~ cell envelope structure

      (≥ 7 layers VS humans' 1 layer)

~ mechanisms for motility

~ mechanisms for adhesion

State the definition of a bacterium:

A microorganism whose body is procaryotic (unicellular).

♦ The term "bacteria" is plural.

Define appendage:

A component which project from the body.

Questions to ask...

How many appendages does M/O have?

How will this affect me?

FLAGELLA - EXTERNAL

Flagella are mainly present in M/Os of which shapes?

Mainly present in bacilli & spirilla

FLAGELLA - EXTERNAL

What are the 3 purposes of flagella?

 ~ motility

or

~ chemotaxis (to detect a specific chemical)

or

~ phototaxis (ability to detect light)

Note: psychrophiles are negatively phototactic and only like cold and absence of light.

FLAGELLA - EXTERNAL

What is the composition of a flagellum?

A flagellum is comprised of:

BODY (anchors)

HOOK (moves, spins)

FILAMENT (can regenerate if cut)

FLAGELLA - EXTERNAL

Is the body attached to the microorganism, or IS IT the M/O?

The body is attached to the M/O.

FLAGELLA - EXTERNAL

Each bacterial species has specific # and arrangement of flagella...

~ Monotrichous

(one flagellum)

~ Lophotrichous

(2 flagella, usually opposite sides of M/O)

~ Amphitrichous

(flagella fanned out in 2 groups opposite sides of M/O)

~ Peritrichous

(flagella all around M/O)

What are 2 methods to determine if a microorganism is motile?

SEMISOLID STAB

(colony visible distinctly separate from stab line)

HANGING DROP SLIDE

(technically possible BUT not a good method since M/O dies from heat quickly and isn't stained)

Chemotaxis and Phototaxis

Determined by trial and error, reading can be +/-

Chemical/different types of light placed on opposite end of slide, watch for movement,

done one chemical at a time.

FLAGELLA: INTERNAL

Is an internall flagellum an appendage?

No, it is not an appendage.

It is never used for chemotaxis or phototaxis.

FLAGELLA: INTERNAL

a/k/a "periplasmic" are found in:

Internal/Periplasmic flagella

found mostly in spirochetes.

FLAGELLA - INTERNAL

Location and purpose

Located within cell envelope between cell wall and cell membrane.

Purpose: varied & precise movement

(↑ risk of infection to host)

PILI

singular: "pilus"

Present only in Grm-

but not in ALL Grm-

Questions to ask...

Is M/O Gm+ or Gm-? Does M/O have pilus?

PILUS

Long, tube-like structure,

originates from one bacterium and attaches to another.

Both ends of tube are open.

Pili are used during Conjugation.

Explain...

Conjugation is called Transformation in lab.

Pili are used in this process, which isn't the same as Reproduction, and is more of an Association between M/Os.

During conjugation/transformation,

a PLASMID comes into play.

What is a plasmid?

An excised or copied piece of DNA which is transferred from a donor bacterium to a recipient bacterium through the pilus.

1^st TYPE OF CONJUGATION of Prokaryotic Cells

during shift from favorable to unfavorable environment...

Donor bacterium knows the other cannot tolerate  - environment, builds pilus, copies its strong genes (plasmids), sends plasmids to recipient bacterium via pilus, both bacteria survive.

2^nd TYPE OF CONJUGATION of Prokaryotic Cells

Donor bacterium knows the other cannot tolerate  - environment, builds pilus, EXCISES its strong genes (plasmids), sends plasmids to recipient bacterium via pilus, DONOR DIES.

example: MRSA is highly transformed

APPENDAGES: Fimbrae

~ have bristle-like proteins, stick out all over surface 

    of M/O

~ adhesive

~ linked to process of infection

    (due to length of association with host's system

     through adhesion)

CELL ENVELOPE COMPOSITION

Glycocalyx

~ outermost layer of cell envelope

~ composition varies (usually polysaccharides)

~ thickness varies

CELL ENVELOPE COMPOSITION

2 most common types of Glycocalyces

1. SLIME LAYER: loosely bound, prevents water & nutrient loss, making M/O stronger, less leaky. (This is less threatening than M/O with capsule.)
2. CAPSULE: tightly bound & sticky (can't be removed by meds), protects against WBCs due to adherence
   

examples of ENCAPSULATED microorganisms...

Streptococcus pneumoniae

(eats holes in simple squamous epithelium of alveoli and capillaries, then blood pools into alveolar regions. This is "fluid in the lungs".)

Haemophilus influenzae

Bacillus anthracis

CELL WALL ♥ PEPTIDOGLYCAN

in Gram + M/Os because...

Peptidoglycan is the most important component of the cell wall, as it's very rigid and prevents collapse/bursting, helps maintain shape.

How many

PROKARYOTIC CELL MEMBRANES

is common and why?

5 cell membranes are common because of selective permeability (into/out of cell body).

Composition varies - some resemble human cell membranes.

CELL ENVELOPE COMPOSITION

List main components...

1. Glycocalyx
2. Cell wall
3. Cell membrane
4. Cytoplasm (chromosome, plasmids, ribosomes, storage bodies, endospores)

CHROMOSOME

within prokaryotic cell's cytoplasm

1. one double helix, loose, no nucleus
2. looped or linear shape
3. DNA is coiled
4. contains ≈250,000 genes
5. genes used for many purposes, mainly protein synthesis (ie, enzymes)

What to Sulfa medications target?

DNA

Define PLASMID

COPY of a small segment of DNA

~or~

EXCISED SEGMENT of DNA

Unique features of Plasmids

They are intended for donation

or have just been received.

Only Gram - bacteria use plasmids*

*but not all Gram- M/Os do it*

1^st of 2 Purposes of PLASMIDS

To impart Resistance, survival.

    (accomplished by plasmid type "P_r")

Describe how Plasmids

impart resistance

from one M/O to another.

>  An environment has become unfavorable.

>  M/O#1 is OK (resistant) and M/O#2 isn't OK 

    (susceptible).

>  Here the plasmid is usually a copy (not excised).

    This plasmid's purpose: resistance "P_r"

>  Plasmid sent via Pilus (singular) from M/O#1 to

     the other.

>  M/O#2 is now resistant, no longer susceptible.

2^nd of 2 Purposes of PLASMIDS

To improve Abilities (not linked to resistance)**

**accomplished by "P_a" plasmids

Describe how one M/O improves abilities of another M/O by donating a plasmid.

>  An environment is favorable.

>  Both M/Os are OK (resistant).

>  Here the Abilities plasmid (P_a) contains genes

    that M/O#2 doesn't have.

    ***Plasmid's purpose: PLANNING ONLY (not survival)

>  Plasmid sent via Pilus (singular) from M/O#1 to

     the other.

>  M/O#2 now has NEW ABILITIES.

Most effective way of killing M/Os?

Target the Ribosomes with medication.

why?

Because it's where Proteins are synthesized.

Prokaryotic Ribosomes

>>where located? size?

Prokaryotic ribosomes float in the cytoplasm and are

smaller/less dense (70S) than

eucaryotic ribosomes (80S).

S= Svedberg Unit (a unit of mass)

Why does medication target

prokaryotic ribosomes successfully?

MAJORITY OF MEDS work by killing 70S ribosomes because of ↓ risk of damage to humans (80S eucaryotic).

STORAGE BODIES

of prokaryotes

2 types

INCLUSIONS used for basic nutrients

Dedicated inclusions - 1 type of nutrient (ie, carbs).

General inclusions store variety of nutrients.

GRANULES have variety of purposes.

Pigment Granules (S. marcescens) purpose unknown

Gas Granules - one purpose: float for survival

The process of SPORULATION

produces what?

ENDOSPORES

a/k/a

"SPORES"

The ONLY type of

prokaryote capable of sporulation is:

BACILLI are the only type

capable of sporulation.

(example: B. anthracis)

When does a bacillus undergo the process of sporulation?

When it is near death.

Describe 4 Stages of Sporulation

1) chromosomes are replicated

    (some M/Os make 10, some make 1,000)

2) envelope of nearly dead M/O is used to envelope

    new chromosomes

3) spores are released

4) spores eat & grow to match size of original

Define SPORE

Spore = a copied chromosome

a/k/a "clone" that is wrapped in pieces of the M/O's old envelope

In sporulation the ORIGINAL MICROORGANISM is referred to as...

VEGETATIVE FORM

not not not

"parent cell"

Name the 3 types of Appendages

for prokaryotic cells

Flagella, Pili, Fimbrae

Prokaryotic Cell Envelope

is composed of what?

Glycocalyx (1 layer), Cell Wall (1 layer)

&

Cell Membranes (5 or more layers)

(remember bacteria have ≥ 7 layers/covers)

Name the 4 structures found in Cytoplasm of prokaryotic cells.

Chromosomes

Plasmids

Ribosomes

Storage Bodies

Range of size of Bacteria

0.2 microns (µm) - Bacilli

to

250 microns (µm)- Spirochetes

Implications of small size of bacteria...

Bacteria can hide from the immune system.

Bacteria can fit everywhere/harm everywhere.

What gain is there in bacteria having certain shapes?

SURVIVAL

COMMON SHAPES (types) of Bacteria

Coccus - roundish (not perfect sphere)  

    Bacillus - rod, elongated (found where nutrients

    are dispersed, long shape ↑ ability to eat)

Coccobacillus - elongated but still round

    Vibrio - crescent moon shape (always in

    windy environment, hanging)

Spirillum - spiral shaped

    Spirochete - spiral, highly coiled

define

PLEIMORPHISM

definition: Changing shape/morphing.

**MOST microbes are created with

1 shape and remain so.

**A few, Pleimorphic, species

can have more than one shape.

Most Pleimorphs have changed shape because of what?

access to NUTRITION

(if nutrients in Env. disperse, M/O has to elongate to increase reach)

A 2nd type of Pleimorph has changed shape because:

HEREDITY

just because this M/O

can change shape

Name 2 Pleimorphic bacteria

Rhizobium

Corynebacterium

Arrangements of Bacterial cells

~a LIFESTYLE~

Some bacteria live as Independents (E. coli)

Others live in Association,

but not necessarily for protection or sharing.

7 types of

Bacterial cell Arrangements

 Diplococci: 2 paired cocci

Tetrads: always cocci, 4 together

Sarcinae: cocci clustered in multiples of 8

7 types of

Bacterial cell Arrangements

(continued)

Streptococci: cocci living in a straight chain (a/k/a serial arrangement)

**causes a wound that is wide but superficial

Staphylococci: cluster of cocci,

NOT in multiples of 8

**wound deep

7 types of

Bacterial cell Arrangements

(continued)

Diplobacilli: side by side contact of bacilli

Streptobacilli: straight chain of bacilli

example: B. megaterium (a large, rare strep)

ID of Bacteria

is based on 6 criteria.

Name them...

1)  morphology (shape, size, arrangement)
2)  Gram status
3)  presence of specific structures  

      (internal/external appendages, storage bodies)
4)   colony characteristics (streak plate)

5)  biochemical reactions

6)  nucleic acid composition (DNA analysis)

Bacteria with unusual traits

#1 - Obligate Intracellular Parasite

Obligate intracellular parasites must live inside a cell, eats it from inside out.

Immune system can't see since it's hidden in cell. Best defense is vaccination.

Bacteria with unusual traits

#1 - Obligate Intracellular Parasite

Rickettsias - 3 examples

Mammal host→Arthropod (lice, ticks)→Human

Rocky mountain spotted fever

(destroys connective tissue)

Typhus will go into all human cells

(not fastidious)

Bacteria with unusual traits

#1 - Obligate Intracellular Parasite

Chlamydias - 3 examples

Eye infection from environment.

STD (human transmission)

Ornithosis (infection from pet bird)

Bacteria with unusual traits

#2 - Cell Wall deficient bacteria

Mycoplasmas

Mycoplasma:

With no cell wall, M/O releases sterols (alcohol) when it's threatened.

(ie, Atypical Pneumonia eats alveoli while releasing sterols. LETHAL)

Bacteria with unusual traits

#3 - Photosynthetic bacteria

Photosynthetics:

• Cyanobacteria
• Green & Purple Sulfur bacteria
• Myxobacteria fruiting bodies

What contains every known fact about every known bacteria?

Bergey's Manual of

Systemic Bacteriology

explain

Evolutionary-VS-Phenetic Relationships

in Classification

Evolutionary: scientists want the M/O name to include ALL characteristics (too complex)

Phenetic: scientists want to name according to morphology (size, shape, etc.) ONLY (too simplistic)