Microbiology - Dr Magrann

thelemicbathBiotechnology

Feb 20, 2013 (4 years and 3 months ago)

119 views

Microbiology

Unit One Review

VOCABULARY


Microorganisms
: organisms that are too small to be
seen with the unaided eye.


Normal microbiota
: microorganisms that are normally
found on or in the body and do not cause disease.


Germ
: rapidly growing cell


Pathogen
: microbe that causes disease.


Bacteriology
: a study of bacteria.


Mycology
: a study of fungi.


Parasitology
: the study of protozoa, parasites, and
warms.


Immunology
: a study of immunity.


Virology
: the scientific study of viruses.


Biotechnology
: the industrial application of
microorganisms, cells, or cell components to make a
useful product.


Microbial ecology
: the study of the relationship
between microorganisms and their environment;
originated from Beijerinck and Windogradskyi.


Microbial genetics
: study of the mechanisms by which
microorganisms inherit traits.


Microbial physiology
: the study of the metabolism of
microbes.


Molecular biology
: the science of dealing with DNA and
protein synthesis of living organisms.


Genomics
: the study of an organisms genes; used to
classify a microorganisms.


Bio remediation
: bacteria degrade organic matter in
sewage. Bacteria also degrade or detoxify pollutants
such as oil and mercury.


Genetic engineering
: a new technique for
biotechnology. Bacteria and fungi can produce a variety
of proteins including vaccines and enzymes.


Taxonomy
: the science of the classification of organisms.


Spontaneous generation
: the idea that life could arise
spontaneously from nonliving matter.


Biogenesis
: the theory that living cells arise only from pre
-
existing
cells.


Probiotic
: adding microbes to your diet.


Nosocomial diseases
: acquired in hospitals; an infection that
develops during the course of a hospital stay and was not present at
the time the patient was admitted.


Neonate
: newborn


Immunocompromised
: vulnerable to disease caused by normal
microbiota.


Fermentation
: the enzymatic degeneration of carbohydrates in
which the final electron acceptor is an organic molecule (contains
carbon). For example, ATP is synthesized by phosporylation
(adding phosphate) and oxygen it is not required. Fermentation is
the process that yeasts use to convert sugars to alcohol in the
absence of air.


Pasteurization
: the process of mild heating to kill particular spoilage
microorganisms or pathogens.


Anaerobic
: without oxygen

MICROORGANISMS



Too small to be seen with the unaided eye.


Decompose organic wastes.


Are producers in the ecosystem by photosynthesis. These
include plants, algae, fungi, and cyanobacteria only.


Produce industrial chemicals such as ethanol (a solvent;
solvents dissolve substances) and acetone.


Produce fermented foods such as vinegar, cheese, bread,
beer, wine, and other useful products.


Produce products used in manufacturing (e.g. cellulose) and
disease treatment (e.g. insulin from

E. coli
).


A few microorganisms are pathogenic (cause disease).


Knowledge of microorganisms allows humans to:



Prevent food spoilage



Prevent disease



Understand aseptic technique to prevent contamination
and medicine, surgery, and in microbiology labs.

THE GERM THEORY OF DISEASE



Louis Pasteur, while he was studying
fermentation, found that microorganisms
are what cause disease.

KOCH’S POSTULATES



OBSERVE:
the same pathogen must be present
in every case of the disease.


ISOLATE:
the pathogen must be isolated from
the diseased host and grown in pure culture.


INOCULATE:
the pathogen from the pure
culture must cause the disease when it is
inoculated into a healthy, susceptible laboratory
animal.


RE
-
ISOLATE:
the pathogen must be isolated
from the inoculated animal and must be shown
to be the original organism.


MICROBIOLOGISTS



Aristotle: Spontaneous generation:
darkness + dampness + grain = mice.


Linnaeus
: established a system of scientific nomenclature. Each organism
has two names; genus and specific epithet (species).


Janssen:
invented the compound microscope


Galileo:
improved both the microscope and telescope.


Van Leeuwenhoek
: first observation of life microorganisms in teeth
scrapings, and rain water.


Hooke
: first observation of cells. Devised cell theory: all living things are
composed of cells.


Redi
: demonstrated that maggots grew only in the meat in which the flasks
were not covered.


Virchow
: cells arise from pre
-
existing cells; the beginning of the biogenesis
(cell) theory.


Agostino Bassi
: showed that a silkworm disease was caused by a fungus.


Ignaz Semmelwise:
advocated midwives to wash their hands when
going from one obstetric patient to another to prevent transmission
of for puerperal fever.


Pasteur:

fermentation, pasteurization processes. Pasteur showed
that microbes are in the air, rain, spoiled foods, and cause disease
in animals. Discoveries included the relationship between microbes
and disease, immunity, and anti
-
microbial drugs (Germ Theory of
disease). His work led to the first vaccine (chicken cholera). He also
invented the rabies vaccine. His evidence was proof of biogenesis;
led to aseptic technique (by Lister) to prevent contamination in
laboratory and medical procedures.


Koch:

Koch’s postulates, pure cultures; he proved that a bacterium
causes anthrax and provided the experimental steps (Koch’s
postulates) to prove that a specific microbe causes a specific
disease.


Lister
: studied sewage in cattle fields; used phenol for aseptic
surgery to disinfect and prevent surgical wound infections after
looking at Louis Pasteur’s work.


Jenner
: invented the vaccine for small pox: he inoculated a person
with the non
-
deadly cow pox virus. The person became protected
from the deadly smallpox virus. He called this protection “immunity”.
He then made the first “vacca” (vaccination) for cows. His work
began when he saw milkmaids touching cows with lesions on their
udders; milkmaids were not contracting smallpox.


Ehrlich
: developed first antibiotic drug: Salvarsan, to treat syphilis;
coined the term "chemotherapy".


Von Behring
: Discovered diptheria antitoxin.


Ross:
discovered that mosquitoes transmitted malaria


Metchnikoff:

discovered phagocytosis of white blood cells when he
observed a thorn in a starfish. He began the field of immunology and
studied the immune response.


Fleming
: discovered the first antibiotic (penicillin). He discovered that
Penicillium

fungus killed

Staphylococcus aureus
, when he found a green
mold growing on his Petri dish of bacteria.


Chain and Florey:
produced penicillin for large
-
scale manufacture during
WWII.


Lancefield
: classification of Streptococcus.


Griffith
: found a “transformation principle” in bacteria, known as DNA today.
Non
-
virulent streptococci (can’t cause disease) were formed into virulent
strains.


Watson and Crick
: discovered the structure of the DNA molecule


Jacob and

Monod:
discovered the role of messenger RNA in protein
synthesis.


Delbruck and Hershey:
discovered the

replication mechanism and the
genetic structure of viruses.



Tonegawa:
antibody genetics


Prusiner:
discovered the disease
-
causing protein called a prion (smaller
than a virus).

SELECTED NOBEL PRIZES IN PHYSIOLOGY



1901

Behring



diphtheria antitoxin


1902

Ross




malaria transmission


1905

Koch




TB bacterium


1908

Metchnikoff



phagocytosis


1945

Fleming, Chain, Florey

penicillin


1952

Waksman



streptomycin


1969

Delbruck, Hershey


viral replication


1987

Tohegawa



antibody genetics


1997

Prusiner



prions

MICROSCOPY



Immersion oil
: keeps light from bending and allows lens
to be refracted.


Resolution
: ability of two lenses to distinguish two
points.


Parfocal
: focused in all lenses.


Depth of field
: how much of the background is in focus
at the same time that the foreground is in focus.


Refractive Index
: a measure of the light
-
bending ability
of a medium


Numerical aperture
: numerical aperture increases as
depth of field decreases.


Resolution power
: limits the useful magnification of the
microscope resolving

ESSAY QUESTIONS



Compare and contrast the seven major groups of microbes.


Explain the debate over spontaneous generation, name the
scientists involved in the debate, and describe their contributions,
stating whether they were for or against the theory of spontaneous
generation.


List ten microbiology pioneers that we studied, and describe their
contributions to microbiology.


Differentiate among the brightfield, darkfield, dissecting, phase
contrast, fluorescence, differential interference contrast, SEM, TEM,
and scanning probe types of microscopes, including their purpose,
function, or any advantages and disadvantages that we studied.


Differentiate between eukaryotic and prokaryotic cells.


Draw a picture of a typical prokaryotic cell and label it. Below your
drawing, pick any five structures you drew and discuss the structure
and function of each one.


MICROBES COMPARISON CHART


BACTERIA

Prokaryotic

Peptidoglycan cell walls

Reproduced by binary fission

Uses organic and inorganic chemicals or photosynthesis for energy

Shapes are rod, coccus, spiral

ARCHAEA

Prokaryotic

Lack peptidoglycan

Live in extreme environments

Include methanogens, extreme Halophiles (love salt), extreme thermophiles
(love heat and cold)

FUNGI

Eukaryotes

Cell walls have chitin

Heterotrophes: use only organic chemicals for energy

Molds and mushrooms are multicellular; consist of masses of mycelia,


which are composed of filaments hyphae.

Yeasts are unicellular

PROTOZOA

Eukaryotes

Absorb or ingests organic compounds

May be motile via pseudopods, cilia, or flagella

ALGAE

Eukaryotes

Cell wall contain cellulose

Uses photosynthesis for energy

Produces oxygen and organic food for other species

VIRUSES

Non
-
cellular intracellular parasites; lives at the expense of host

Contain either DNA or RNA surrounded by a protein coat

May have an envelope

Smallest of all microbes

Replicates in living host cell

Antibiotics do not work; requires antiviral agents

HELMINTHES

AND

NEMATODES

Eukaryotes

Helminthes: parasitic flat worms and tapeworms

Nematodes: parasitic roundworms

Endoparasites: animals that live inside other animals through fecal


contamination

Microscopic stages of life cycle

Parasite is in the bite of mosquito or bug; spreads infection in body

MICROBES COMPARISON CHART


Spontaneous Generation Theory


Aristotle
thought that the mice grew from the grain and
hay, and he coined the term “Spontaneous generation”


Virgil:
bees grew from honey and that flies grew from
meat.


Redi:
maggots in meat were caused by flies laying eggs;
they only grew on the meat in which the jars were not
covered.


John Needham

believed in spontaneous generation;
boiled nutrient broth to kill all microbes, put a non
-
sterile
cork in the flask, found that the broth grew microbes.


Louis Pasteur:
made a glass flask with an “S” shaped
bend in it so that bacteria could not enter into it but air
could get in. He placed chicken broth in the flask and
boiled it so that it was sterile and observed that there
was no bacterial growth in the broth.


COMPARISON OF MICROSCOPES


BRIGHTFIELD

Dark objects are visible against a bright background.

Light reflected off the specimen does not enter the objective lens

Not for looking at live cells

Maximum resolution is 0.2µm and maximum magnification is
2000x

Stains are used on specimens

DARKFIELD

Light objects are visible against dark background

Used for live cells, cilia, flagella

Especially good for spirochetes

Uses special condenser with an opaque disc that eliminates all light
in the center

PHASE
-
CONTRAST

No staying required

Accentuates diffraction of the light that passes through a specimen

Good for live cells; good contrast

Most sensitive; cilia shows up

Not three
-
dimensional

DIFFERENTIAL

INTERFERENCE


CONTRAST

Uses two beams of light

Shows three dimensions

Has a prism to get different colors

Good for live cells (unstained)

Best resolution

COMPARISON OF MICROSCOPES


FLUORESCENCE

Uses ultraviolet light

Stained cells with fluorescent dye; energizes electrons and creates
visible light

No live cells

Quick diagnosis of TB and syphilis

TRANSMISSION

ELECTRON

Get flat images

Have vacuum pumps to allow electrons to float better

Stain with heavy metal salts

Shows sections of cell, revealing organelles

Requires an ultramicrotome

Best resolution

SCANNING

ELECTRON

Surface view only

Needs a vacuum

No live cells

Three
-
dimensional view

SCANNING
PROBE

Physical probe scans the specimen

Raster scan: image is cut up into pixels and transmitted to computer

Not limited by diffraction

Slower in acquiring images

Maximum image size is smaller

EUKARYOTIC

PROKARYOTIC

One circular chromosome, not membrane
-
bound

Paired chromosomes, membrane
-
bound

No histones

Histones present

No organelles

Organelles present: Golgi complex, ER, mitochondria, chloroplasts

Peptidoglycan cell walls

Polysaccharide cell walls

Reproduce by binary fission

Reproduce by mitosis

No true nucleus; no nuclear membrane

True nucleus; nuclear membrane; also has nucleoli

Glycocalyx present as capsule or slime layer

Present in some cells that lack a cell wall

Plasma membrane has no carbohydrates and lack sterols

Plasma membrane has carbohydrates and sterols

No cytoskeleton

Has a cytoskeleton

Ribosomes are small (70S)

Ribosomes are large (80S)

Prokaryotic Cell Drawing

Structure and Function of Prokaryotic
cells


PLASMA MEMBRANE


CELL WALL


GLYCOCALYX


CAPSULE


SLIME LAYER


FLAGELLUM


SEX PILUS


FIMBRAE


PLASMA MEMBRANE


Consists of a phospholipid bilayer,
peripheral and integral proteins, and
transporter proteins.


Function: selectively permeable; allows for
passage of only certain molecules.


Gram negative organisms also have an
outer plasma membrane with LPS, which
is an antigen and contains a toxin.

CELL WALL


Composed of peptidoglycan, which is a
series of two sugars, NAM and NAG,
connected with a peptide (or protein)
bond.


Function of cell wall: provides rigidity and
protection from osmotic lysis.

GLYCOCALYX


A sticky coating external to the cell wall,
made of polysaccharide, polypeptide, or
both. Made inside of the cell and secreted
to the cell surface.


May be either a capsule (organized) or a
slime layer (not organized).


Capsule function: to protect from
phagocytosis.


Slime layer function: allows for attachment
to host.

FLAGELLUM


Made of a protein called flagellin.


Consists of a basal body, turning disc,
hook, and filament.


Function: ATP is used to turn the discs in
the basal body, which turns the whole
flagella to provide movement.

FIMBRAE


Hair
-
like structures around the cell, made
of protein.


Function: Allows bacteria to attach to host.
Strains of bacteria that are without fimbrae
cannot attach and disease does not occur.

SEX PILUS


Special kind of fimbrae, but longer.


Function: allows two cells to attach for
conjugation and transfer of DNA from one
cell to another.