Lec1 Microbial World.pptx - Cal State LA - Instructional Web Server

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Dec 16, 2012 (4 years and 10 months ago)

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Lecture 1: The Microbial World

Edith Porter, M.D.

1


Definition of Microbiology


Size dimensions


Classification of microbial agents


Microbial diversity


Role of microbes in nature


Beneficial


Environment


Normal
microbiota


Commercial use and industrial applications


Harmful


Disease causing


History of Microbiology


2


Micro


Small (micrometer range)


Not visible with the unaided eye


Bio


Living


Able to
reproduce


3

1 inch

1 cm

1 mm (1/10 of 1 cm)

1
m
m (1/1000 of 1 mm)

1 nm (1/1000 of 1
m
m)

Human Egg cell
(almost 1 mm)

Erythrocyte (7
m


䉡捴敲極洠⠲(

4
m


䱡L来g噩牵猠⠲〰 湭n

4


Cellular organisms


Eukaryotes (have a nucleus)


Prokaryotes
(do not have a nucleus)







Acellular

agents


Viruses (nucleic acid + protein)


Viroids

(nucleic acid)


Prions

(protein)

Cell membrane

Nucleus with
genetic
material

Nuclear membrane

Cell membrane

Genetic material
in cytoplasm

5

Domain

Bacteria

Domain

Archaea

Domain

Eukarya

Animals


Helminths

Plants

Fungi

Protozoa

Algae

Prokaryotes

Protists

Slime

molds

6

Eukaryotes

7


Bacteria


Peptidoglycan cell walls


Binary fission


For energy, use organic
chemicals, inorganic chemicals,
or photosynthesis


Some produce molecular oxygen


Archaea


No peptidoglycan


Often in extreme environments


Diverse metabolic pathways


Not known to cause disease




Cellulose cell walls


Use photosynthesis
for energy


Produce molecular
oxygen and organic
compounds

8


Chitin cell walls


Use organic chemicals
for energy


Two forms


Molds


Multicellular


Consisting of masses of
mycelia composed of
filaments called
hyphae


Yeasts


Unicellular


Dimorphic shift

9


Unicellular


Absorb or ingest

organic chemicals


May be motile via
pseudopods
, cilia,

or flagella

10



Multicellular

animals


Parasitic
flatworms and
roundworms are
called
helminths


Microscopic
stages in life
cycles

Dirofilaria

immitis



Viruses are replicated
only when they are in a
living host cell


Consist of DNA
or

RNA
core


Core is surrounded by a
protein coat


Coat may be enclosed in
a lipid envelope (from
host cell)


Not all viruses are
harmful!



Proteinaceous

infectious
particles


Consist of protein only


Prions

induce
conformation changes of
normal counter parts


Body’s response leads to
symptomatic disease


Neurodegenerative
disorders


CJD


BSE



Brain section of animal with BSE


Genus name followed by species name


Typically relate to the discoverer, habitat,
properties of the organism or its role


Genus name capitalized, species name lower
case


In italic (or underlined)

14


Escherichia coli
or

E
. coli





Neisseria

meningitidis

or N
.
meningitidis

space

Discoverer
was Escherich

lives in
colon

Discoverer
was Neisser

causes
meningitis

15

space

16


Plankton


Geochemical
cycling


Microbes recycle carbon,
nutrients, sulfur, and
phosphorus that can be used
by plants and animals


Oxygen production


Normal flora: digestion,
vitamin production etc


Cellulose digestion by
protozoa in termite gut


Vitamin K production by
human intestinal flora

17

Microbes on human tongue
in a healthy individual


A small percentage of all
microorganisms are
involved in diseases


Humans, animals and
plants can be affected


Opportunistic and obligate
pathogens


Diseases
linked to


microbial proliferation (e.g.
pus, pneumonia)


toxic substances (e.g.
botulism, liver cancer)

18

An organism that contains a nucleus
and a cell membrane is:


a.
Virus

b.
Prokaryote

c.
Helminth

d.
Archaea

19

Choose the correct form of naming a
microbe:


a.
Pseudomonas maltophilia

b.
P. maltophilia

c.
Pseudomonas m.

d.
P. m.


20


Development of tools to study microbes


Microbes exist


Microbes
cause disease


Humans have a defense system


Drugs
that kill microbes can be developed


Microbes can be
exploited to the benefit of
humans



21


For identification


Optics (microscope)


Glass slides


Dyes


Culture media, inoculation material


Biochemical and
molecular
genetic assays



Advanced
tools to
study their role


In vitro

models


Animal models


22


~ 1600
Galilei
: Lenses for use in
a microscope


1665: Robert Hooke described
cells


1676
Van Leeuwenhoek: first
recorded description of
microbes
called “
animacules



17
th
/18
th

century: spontaneous
generation


Living things arise from non living
matter


1858 Virchow proposes concept
of
biogenesis


Cells arise from living cells


1861 Pasteur disproves theory
of spontaneous generation (and
proves concept of biogenesis)


23

Fermentation, Pasteurization

24


Pasteur’s S
-
shaped flask kept microbes out but let air in


1847
Semmelweis


childbed fever


1867 Lister


antiseptic
surgery with phenol


1876 Koch


First proof that microbes cause
disease:
Bacillus
anthracis

causes anthrax


1884
Gram stain developed,
Koch’s postulates
formulated

http://www.acponline.org/bioterro/anthrax/graphics/cutaneous.jpg

http://www.cdc.gov/ncidod/eid/vol7no2/images/cover_final_rgb.jpg

http://www.chemistryexplained.com/images/chfa_03_img0510.jpg

25


Microbe must be present in every case of
disease and not in the healthy one.


Microbe must be isolated in pure culture.


When inoculated into a healthy tissue the
same disease must arise.


From this diseased tissue the same microbe
must be re
-
isolated in pure culture.

26

27


1798 Jenner: cow pox
vaccination


1884 Metchnikoff:
phagocytosis


1890 Ehrlich: theory
of antibodies


1921 Fleming:
lysozyme



28


End of 19
th

century: dyes


1910 Ehrlich:
First
c
hemotherapeuticum

(
salvarsan
: arsenic
compound to treat
syphilis)


1928
Fleming: first
antibiotic (penicillin
)


First successful treatment
in 1942


29


Food preparation
(fermentation)


Bread, yogurt,
kim
-
chi,
cheese, beer, wine and many
more


Production of
Chemicals


acetone,
butanol
, alcohol,
organic acids and many more


Drugs


Antibiotics, some cancer
drugs



Biotechnology


Bioremediation


Clean up of BP oil spill


Genetic engineering


Recombinant drugs


Immunoassays


Rebecca Lancefield:
serotyping

of
Streptococcus spec.


30


Emerging
infectious diseases and topics


Avian
Flue (H5N1) and swine flu


West
Nile
virus encephalitis


Mad cow diseases (
prions
)


E. coli O157:H7


Biofilm


On teeth, mucosal surfaces, rocks, medical devices


Hard to penetrate, source of recurrent infections



Emerging
antibiotic resistance


Vancomycin

resistant staphylococci and
enterococci


Multidrug resistant tuberculosis strains


Resistance among malaria strains


31

S.
aureus


Biofilm


Microbial agents include prokaryotes,
eukaryotes and
acellular

agents


Prokaryotes
are cells without nucleus


Bacteria,
a
rchaea
,
fungi
,
algae
,

and protozoa

are in the
MICROMETER

range (
m
m)


Viruses,
acellular

agents, are in the
NANOMETER

range (nm)

32