1. Acidophiles 2. Neutrophils 3. Alkaliphiles

UNIT 2 Flashcards by Rosety Millo

Study of microorganisms

Microbiology

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Increase in cell number

Microbial growth

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Splits into two cells

Binary fission

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Time required for a cell to divide

Generation time

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Cells form an initial outgrowth (a bud)

Budding

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Microbes that grow and multiply in or on culture media

Culture

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A group of descendants of an original cell

Colony

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Aka: AXENIC

Pure culture

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Pure culture

Contains a single microbial species

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6 definition of terms

Microbial growth
Binary Fission
(Generation Time)
Budding
Culture
Colony
Pure Culture

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3 Physical requirements for growth

Temperature
pH
Osmotic Pressure

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Category in Temperature

PSYCHROPHILES
PSYCHOTROPHS
MESOPHILES
THERMOPHILES

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It is sensitive to temperatures over 20’

PSYCHROPHILES

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optimum growth at 20’C to 30’C

PSYCHROTROPHS

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Optimum growth at 25’C to 40’C

MESOPHILES

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EXTREME THERMOPHILES

grown at 80’C or higher

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Optimum growth oa 50’C to 60’C

THERMOPHILES

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Category in pH

Acidophiles
Neutrophils
Alkaliphiles

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Lactobacillus acidophilus

Acidophiles

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Grow at pH 5.4 to 8.5

Neutrophiles

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Vibrio cholerae

Alkaliphines

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brown at high pH (7 to 12)

Alkaliphiles

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Category in Osmotic Pressure

Obligate Halophiles
Facultative Halophiles

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Aka: Extreme Halophiles

Osmotic pressure

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Does not require high salt concentration for growth

Facultative Halophiles

Requires very high concentration 20-30%

Tolerates 2-15% salt concentration

Facultative Halophiles

Grow at a very low pH (0.1 to 5.4)

Acidophiles

7 Chemical requirements for growth

A. Carbon B. Nitrogen C. Sulfur D. Phosphorus E. Others F. Oxygen G. Carbon Dioxide

Category of Carbon

Chemoheterotrophs Chemoautotrophs

Organic carbon sources

Chemoheterotrophs

Inorganic energy sources

Chemoautotrophs

May need to consume other living organisms to live

Chemoheterotrophs

Primary carbon source is carbon dioxide

Chemoautotrophs

Nitrogen

Makes up to 14% of dry cell weight

Sulfur

Used to form proteins and some vitamins

Used to form DNA, RNA, ATP and phospholipids

Phosphorus

Others

K Mg Ca Fe Cu Mo Zn

Growth requirement for aerobic microorganisms

Oxygen ; sources : atmosphere water

5 category of oxygen

Obligate aerobes Facultative anaerobes Obligate anaerobes Aerotolerant anaerobes Micro-aerophiles

It requires oxygen to live.

Obligate aerobes

Mycobacterium tubercolosis

It can use oxet Feb, but can grow in its absence

Facultative anaerobes

Escherichia coli

Can’t use oxygen and is harmed by the presence of toxic forms of oxygen

Obligate anaerobes

Clostridium tetani

Can’t use oxygen but can grow in its absence

Aerotolerant anaerobes

Streptococcus pneumoniae

Micro-aerophiles

Helicobacter pylori

Requires oxygen at low

Micro-aerophiles

Oxygen in anaerobes

O2—metabolism—toxic— Bacterial Product. Death. O2-OH- O2+ H2O2

Breaks down hydrogen peroxide

Peroxidase

Catalase

Converts hydrogen peroxide to water & oxygen

Converts superoxide to oxygen & hydrogen peroxide

Superoxide dismutase

Bacterial growth

Lag phase Lag phase Stationary phase Death or decline phase

Lag phase

No increase in number of living bacterial cells

Log phase

Exponential increase in number of living bacterial cells

Stationary phase

Plateau in number of living bacterial cells; rate of cell division and death roughly equal

Death or decline phase

Exponential decrease in number of living bacterial cells

Superoxide free radical

Superoxide dismutase

Peroxide anion

Catalase Peroxidase

Carbon Dioxide

CO2-loving

Carbon dioxide

Candle jar CO2 generating packet

Require Increase concentration of CO2 and lower levels of O2

Carbon dioxide

Substance containing nutrients in which cells or microorganisms can be grown; may be solid, liquid or gel

Culture media

3 Characteristics of culture media

Contains appropriate nutrients Sterile Incubated at appropriate temperature

Act of introducing microorganisms or suspension of microorganisms into a culture medium

Inoculation

Microbial cells added to a medium in order to start a culture

Inoculum

3 Category of culture media

Solid media Liquid media Semisolid media

Nutrient material that contains a solidifying agent

Solid media

Nutrient material that contains <1% solidifying agent

Semisolid media

Nutrient material that last solidifying agent

Liquid media

Liquid medium in a tube, bottle or flask

Broth

Applicable if high concentration of bacteria is desired

Broth

Loose cap Bacteria is above

Obligate aerobes

Bacteria is in the lower part of the tube

Obligate anaerobes

More bacteria in the top part of the tube and lesser at the bottom

Facultative anaerobes

The bacteria is scattered in the tube

Aerotolerant anaerobes

Agar plate

Difficult to transport and store

Allows for isolation and examination of colonies

Agar plate

For microorganisms that prefer O2

Agar Deep

Inoculating needle is used to stab the solid medium

Agar deep

For easy storage and transportation

Agar slant

Tube of solid medium at an angle for higher surface area

Cannot be degraded by most bacteria

Agar

Some species of red algae

Gracilaria compressa Gelidium cartilagineum Gelidium amansii

Unbranched polysaccharide obtained from the cell walls of some species of red algae

Agar

Melts above 95’c

agar

Does not solidify until it reaches 40’C

Agar

6 Types of culture media

All purpose media Selective media Differential media Enrichment media Chemically defines media Complex media

Microorganisms requiring special culture technique

Mycobacterium tubercolosis Treponema pallidum Obligate parasites Influenza virus Mycoplasma

Exact components are difficult to estimate because of complex ingredients

Complex media

Prepared from pure chemical substances of known composition and concentration

Chemically defined media

Favors growth of a particular microorganism over others by providing essential nutrients

Enrichment media

Used for differentiating between bacteria by using an identification marker for a specific type of microorganisms

Differential media

Allows growth of desired microorganism while suppressing the growth of unwanted microorganisms

Selective media

Has multiple effect

All purpose media

For general purposes of preservation, isolation, storage of cultures and antibiotic sensitivity test

All purpose media

Difference between binary fission from mitosis

No mitotic spindle form

generation time E.coli

30 to 180 mins

generation time M. tuberculosis

12 hours

T. pallidum

33 hours in rabbit testes

M. leprae

10 days in armadillos

Cocci synthesize new cell walls

septal region

Rod shape bacteria

Logarithmic representation of bacterial growth

2^n

the initial outgrowth

a bud

other name of pure culture

axenic culture

how the surface of the colony appears

texture

Texture types

smooth glistening mucoid slimy dry powdery flaky

Transparency

Transparent Translucent Opaque

You can see through them

Transparent

Light pass through them

Translucent

solid-appearing

opaque

Intracellular pigments

color/pigmentation

Many bacteria do not produce any pigment and appear _________

white or gray

Magnifying tool

Colony counter Dissecting microscope

Colony size

Punctiform <1 mm Small 1-2 mm Medium 3-4 mm Large >5 mm

Colony forms

Circular Rhizoid Irregular Filamentous

Colony Margin

Entire Undulate Lobate Filamentous Curled

Colony elevation

Flat Raised Convex Pulvinate Umbonate

Rely on organic compounds as source of food to provide energy and carbon

Heterotrophs

Mesophile/Mesophilic temperature

20 to 40 degrees celsius

Body Temperature

Room temperature

The lowest temperature at which an organism is able to conduct metabolism

Minimum growth temperature

Temperature at which an organism's metabolic activities produce the highest growth rate

optimum growth temperature

The highest temperature at which an organism continues to metabolize

maximum growth temperature

when temperature exceed maximum growth temperature, the organism's _________

protein are permanently denatured and dies

P S Y C H R O P H I L E S other name

cryophiles

sensitive to temperatures over 20 ̊C optimum growth at 15 ̊C or below

P S Y C H R O P H I L E S

− optimum growth at 20 ̊C to 30 ̊C

P S Y C H R O T R O P H S

− optimum growth at 25 ̊C to 40 ̊C

M E S O P H I L E S

− optimum growth at 50 ̊C to 60 ̊C

T H E R M O P H I L E S

P S Y C H R O T R O P H S Other name

Cold-tolerant bacteria or archaea

grow at 80 ̊C or higher

Extreme Thermophiles

M E S O P H I L E S other name

moderate temperature-loving

T H E R M O P H I L E S other name

Heat-loving

Extreme Thermophiles Example

Geogemma barosii

85 to 121 2 hours in 130

Can destroy most microbes

> 60 degrees

slow microbial growth

50 to 60

rapid microbial growth; produce toxins

25 to 50

grow at very low pH (0.1 to 5.4)

A C I D O P H I L E S

Organs with low pH

Vagina and stomach

the causative agent of peptic ulcer

Helicobacter pylori

A C I D O P H I L E S example

Lactobacillus acidophilus

− grow at pH 5.4 to 8.5

N E U T R O P H I L E S

Lactobacillus produce

lactic acid

− grow at high pH (7 to 12)

A L K A L I P H I L E S

Most bacteria, protozoa, and pathogens grow best at what pH

Neutral

A L K A L I P H I L E S example

− Vibrio cholerae cholera − Alkaligenes faecalis − Agrobacterium spp.

Pressure difference needed to stop the flow of solvent across a semipermeable membrane

Osmotic pressure

require very high salt conc. 20 to 30%

O B L I G A T E H A L O P H I L E S

O B L I G A T E H A L O P H I L E S another name

extreme halophiles strict halophiles

Can survive month in dry conditions due to the ability of its cell wall to retain water

Mycobacterium tuberculosis

− do not require high salt conc. for growth − tolerates 2-15% salt concentration

F A C U L T A T I V E H A L O P H I L E S

Salt-water principle

Water follows salt Sodium attracts water

No net movement of water

Cells in isotonic solution

Shrink because of the net movement of water out of the cell

Cell in hypertonic solution

Undergo gain of water

Cells in hypotonic solution

Solute concentration inside and outside are the same

Isotonic solution

Have higher solute concentration than inside the cell

Hypertonic solution

Has a lower solute concentration

Hypotonic solution

Hypo comes from

Latin word under or low

− organisms that derive energy from organic carbon sources − may need to consume other living organisms to live

C H E M O H E T E R O T R O P H S

Organisms that obtain energy by the oxidation of electron donors in their environment

Chemotrophs

Organism that cannot manufacture its own food by carbon fixation and therefore derives its intake from other sources of organic carbon, mainly plant or animal matter

Heterotroph

Some bacteria can reduce nitrogen gas t

ammonia

S U L F U R sources

proteins, hydrogen sulfide, sulfates

Sulfur is used to synthesize sulfur-containing amino acids and vitamins like

Thiamine - Vitamin B1 Biotin - Vitamin H

used to form DNA, RNA, ATP, and phospholipids

P H O S P H O R U S

P H O S P H O R U S sources

Inorganic phosphate salts, Buffers (from culture medium)

phospholipids are found in _______

cell membranes of bacteria

Growth requirement for aerobic microorganisms

O X Y G E N

F A C U L T A T I V E A N A E R O B E S has ________ enzymes that allow toxic forms of oxygen to be neutralized

catalase SOD (superooxide dismutase)

M I C R O - A E R O P H I L E S example

Helicobacter pylori Campylobacter jejuni

Toxic forms of oxygen

Hydrogen peroxide Superoxide radicals

converts superoxide to oxygen & hydrogen peroxide

Superoxide dismutase:

converts hydrogen peroxide to water & oxygen

Catalase:

Used for cell wall synthesis of gram-positive bacteria

Calcium

CULTURE MEDIA common ingredient

Peptone Beef extract Yeast extract Distilled water agar

The manner in which the inoculum is spread out into the cultured medium

Streaking

A G A R is the ____________ obtained from the cell walls of some species of red algae

Unbranched polysaccharide

some species of red algae

i. Gracilaria compressa ii. Gelidium cartilagineum iii. Gelidium amansii

Who first used agar

Robert Koch

Another solidifying agent

Gellan gum

Inoculating techniques

Stabbing Stab and streak Streaking

Irish moss (Red Algae)

Chondrus crispus

maybe done in media with dilute agar concentration

motility test

useful in demonstrating motility of bacteria

SEMISOLID MEDIA:

For general purposes of preservation, isolation, storage of cultures and antibiotic sensitivity tests

ALL - P U R P O S E M E D I A

ALL - P U R P O S E M E D I A examples

− Peptone water − Nutrient broth − Nutrient agar − Bismuth Sulfite Agar

Allows growth of desired microorganism while suppressing the growth of unwanted microorganism

S E L E C T I V E M E D I A

S E L E C T I V E M E D I A example

− Saboraud’s dextrose agar − Brilliant green agar − Thayer-Martin agar − Lowenstein Jensen Media

pH 5.6 discourages bacterial growth for fungi

Saboraud’s dextrose agar

inhibits G+ bacteria and allows for the growth of G- salmonella

Brilliant green agar

for the growth of Neisseria gonorrheae

Thayer-Martin agar

Used to isolate Salmonella typhi

Bismuth Sulfite Agar

Used to isolate Mycobacterium tuberculosis

Lowenstein Jensen Media

Used for differentiating between bacteria by using an identification marker for a specific type of microorganism

D I F F E R E N T I A L M E D I A

D I F F E R E N T I A L M E D I A examples

− Mannitol salt agar − MacConkey agar − Blood agar

Mannitol salt agar

Staphyloccocus aureus -> halophile

MacConkey agar

Salmonella typhi

Uses hemolytic reaction Used to distinguish bacteria that destroy red blood cells

Blood agar

Blood agar usually contains

sheep or horse blood

contains 7.5 % sodium chloride Both selective and differential has a pH indicator

Mannitol salt agar

Mannitol fermentation

pink to yellow positive

consider as complex, selective, and differential media contains bile salt, and crystal violet that inhibits the growth of g+ bacteria use lactose

MacConkey Agar

The growth in _______ indicates _______ , while _______ does not

pink; lactose utilization; yellow

Lactose fermenters examples

Enterobacter spp Citrobacter spp Klebsiella spp

Lactose fermenters will produce

acid

test the ability of an organism to produce hemolysin, enzyme that damage/lyse red blood cells

Blood agar media

Blood agar media members

Staphylococcus Streptococcus Enterococcus

Partial hemolysis

Alpha hemolysis

Complete hemolysis

Beta hemolysis

No hemolysis

Gamma hemolysis

the destruction of red blood cells

hemolysis

Alpha hemolysis examples

Streptococcus pneumoniae Streptococcus mutans

Beta hemolysis examples

Staphylococcus aureus Streptococcus pyogenes Listeria ivanovii

Gamma hemolysis examples

Escherichia coli Klebsiella pneumoniae Enterococcus faecalis

Favors growth of a particular microorganism over others by providing essential nutrients

E N R I C H M E N T M E D I A

E N R I C H M E N T M E D I A examples

− Chocolate agar − Loeffler’s medium − Brain heart infusion agar

complex or particular nutrient requirement

fastidious organism

Chocolate agar example

Haemophilus influezae

Brain heart infusion agar examples

Streptococci Pneumococci Meningococci

Made up of lysed RBCs

Chocolate agar

Haemophilus influenzae

Pneumonia and sepsis

Prepared from pure chemical substances of known composition and concentration

C H E M I C A L L Y D E F I N E D M E D I A

C H E M I C A L L Y D E F I N E D M E D I A example

− Peptone water − Modified Korthof’s medium − Firm agar

The exact components are difficult to estimate because of complex ingredients

C O M P L E X M E D I A

C O M P L E X M E D I A example

− Nutrient agar − Trypticase soy agar − Eosin methylene blue agar

use to culture most chemoheterotrophic microorganism

C O M P L E X M E D I A

Eosin methylene blue agar is used for

Isolation of the fecal coliforms (E.coli)

Eosin methylene blue agar contains lactose and dyes _______ and _______

Eosin and methylene blue

Microorganism that cannot grow in culture media

Obligate parasites

SPECIAL CULTURE TECHNIQUES armadillos

Mycobacterium leprae (leprosy)

SPECIAL CULTURE TECHNIQUES rabbit testicles

Treponema pallidum (syphilis)

SPECIAL CULTURE TECHNIQUES host cells only

Obligate parasites STD causing chlamydia

SPECIAL CULTURE TECHNIQUES hen's egg

Influenza virus

SPECIAL CULTURE TECHNIQUES Cell culture

Mycoplasma spp

A method of isolating a culture by spreading microorganisms over the surface of a solid culture medium.

S T R E A K P L A T E M E T H O D

A method of inoculating a solid nutrient medium by mixing bacteria in the melted medium and pour the medium into a Petri dish to solidify.

P O U R P L A T E M E T H O D

A plate count method in which inoculum is spread over the surface of a solid culture medium.

S P R E A D P L A T E M E T H O D

UNIT 2 Flashcards

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