Chapter 7-Microbial Growth (Ngoc create)

What phase does population is the most uniform?

Exponential growth

What phase can we see no increase in cell number?

Lag phase

What range does lag phase observe that they are not expressing FtsZ?

From stationary or death phase into a fresh medium

What range does lag phase observe that bacteria have to adapt?

From exponential phase into a fresh medium of different chemical composition

When does biphasic growth occur?

during a medium shift from glucose to lactose (rich to poor culture)

What does Lac permease bring in Biphasic (KIA) growth?

Lactose by transcribing and translating on Lac operon

When does a lag phase not occur?

Cells growing exponentially into a fresh medium of the same chemical composition

Do proka grow faster than euka in exponential phase?

Yes

What phase does it represent the healthy cells?

exponential/log

Bacteria make waste in what phase

stationary

What phase do we expect total number of viable cells remains constant

stationary

What type of bacteria do death phase include?

Escherichia coli, Vibrio cholerae and Listeria monocytogenes (+)

What phase do bacteria cell size cease?

stationary

Are cells active and do they grow on Petri dishes?

they are active but they don’t grow on Petri dishes

why do total of cell remain constant in stationary phase?

a balance between cell division and cell death

Are white cells death? Do they grow in colonies?

White cell are not dead and do not grow in colonies

Long-term stationary

What phase can last months to years?

What is the best-characterized GASP mutations?

rpoS

What phase do we observe the birth and dead rate?

Long-term stationary

How can natural selection be occurred in long-term stationary?

Bacteria population continually evolve so that actively producing cells are those best able to use the nutrients released by their dying brethren and be able to tolerate the accumulated toxins

Growth advantage in stationary-phase phenotype (GASP)

•milk spoilage: lactic acid bacteria (they change the pH of the milk)—>  fungi → proteolytic bacteria (breaks down the protein of milk)

Most organisms grow in …………. environmental conditions

fairly moderate

What happens to extremophiles if the conditions exceed their ability to respond?

they will not grow and eventually may die

Where do extremophiles live?

they thrive in harsh environment

no net moment of water

isotonic

In a hypotonic environment, cells may …………… their …………to prevent water influx and bursting

reduce/osmotic concentration

In a hypertonic environment, cells may …………… their …………

increase/internal solute concentration

MS channels

escape valves to protect cells from bursting

Microbes are adapted to extreme hypertonic environments that require high concentrations of sugars

Osmophiles

What do contractile vacuoles use?

Expel excess water

Compatible solutes

the plasma membrane is always pressed firmly against the cell wall

What type of Nonhalophile?

not loving salt

What type of Halotolerant?

Tolerate salt

What type of Halophiles?

loving salt

What type of extreme halophiles?

really like salt

What is an example of Nonhalophile?

E. coli (they grow best in the absence of salt). They will die if they’re put in MSA.

What is an example of Halotolerant?

S. aureus – MSA used in the petri dish(they can handle salt until they die)

What is an example of Halophiles?

V. cholerae (they have the limit of the salt they can get)

What is an example of Extreme Halophiles?

Halobacterium spp.

How do microorganisms survive with a low (aw) value?

maintain a high internal solute concentration to retain water

What does higher solute mean?

lower aw

An example of osmotolerant microorganism

S.aureus

What organism like acidic environment?

Acidophiles (0-5.5)

What organism include bacteria and protists?

Neutrophiles (5.5-8)

what are marine microorganisms called?

Alkaliphiles (8-11.5)

What organism will most pathogens be found?

Neutrophiles

Can microorganisms regulate their internal environment?

No, therefore they are particularly susceptible to external envi

How can neutrophiles exchange potassium for proton?

using antiport transport system

how do acidophiles maintain their external pH close to neutrality?

By exchanging internal sodium ions (Na+) for external protons

Acidic tolerance response in microbes?

•pump protons out (acidophiles uses the transport of cations into the cell→ decrease the moment of H+ into the cell→ proton transporter pump H+ out if they get in→ appearance of impermeable cell membranes.

•some synthesize acid and heat shock proteins that protect proteins (can found in bacteria because….)

Do many microorganisms change the pH of their habitat?

yes

What are cardinal growth?

min, max, optimum growth temp

What does cardinal growth depend on?

pH and available nutrients

What organism grow better in higher temperature: Euka or Proka?

Proka such as bacteria and archaea

Microorganisms that can grow in moderate temp?

mesophiles

Microorganisms that love the cold

psychrophiles

Microorganisms that tolerate the cold

psychrotolerant

Microorganisms that like heat

thermophiles

Microorganisms that extremely like heat

hyperthermophiles

What proteins do appear to stabilize the DNA of thermophiles?

Nucleoid-associated proteins

………….. are amino acids that are abundant to make polypeptide chain less flexible and more heat stable

proline

proteins that help proteins fold

Chaperones

Protein structure in Hyperthermophiles

•Protein structure:

•presence of chaperones & HSP

•more H bonds (can be broken with heat), (melting break the H-bond) and proline (amino acids that are abundant to make polypeptide chain less flexible and more heat stable)

Do archaea have fatty acid chains?

No, they have isoprene

Fatty acid chains’ characteristics in Hyperthermophiles?

•more saturated, branched and higher molecular weight (makes it harder to crystallize~makes it harder to break)

Not crystallized

What layers and linkages do hyperthermophiles have?

monolayers and ether linkages because most of them are certain species of archaea

What do histone-like proteins in Hyperthermophiles do?

Stabilize DNA

Protein structure in Psychrophiles?

•more α-helix, less b-sheets, 2^nd structure

•more polar, less hydrophobic amino acids

Fatty acid chains’ characteristics in Psychrophiles?

more unsaturated and shorter

Other Psychrophiles characteristics

•Compatible solutes to decrease freezing point

•Crytallized- can’t function

Oxygen is the terminal electron acceptor for the ETC in the metabolic process called……….?

aerobic respiration

Anoxic zone

No Oxygen is present

Oxic zone

There is Oxygen present

Needs oxygen to survive

Obligate aerobe

Grows best in concentration of oxygen lower than in atmosphere

Microaerophile

Can grow with or without oxygen, but prefers oxygen

Facultative anaerobe

Grows equally with or without oxygen

Aerotolerant anaerobe

Cannot survive in oxygen

Strict anaerobe

What is ROS? When will it formed?

ROS is a reactive O2 species that will be formed when cellular proteins such as flavoproteins transfer electrons to O2. it can damage the most dangerous hydroxyl radical.

What are some oxygen species?

•superoxide radical (O₂· ^-)

•hydrogen peroxide (H₂O₂)

•hydroxyl radical (OH·)

What are some protective enzymes?

•superoxide dismutase (SOD)

•catalase (makes water and o2 (will see bubble)- positive)

•peroxidase

Catalase and peroxidase can detoxify the H2O2

What does •superoxide dismutase (SOD) destroy?

superoxide radical (O₂· ^-)

Two important immune system cells that use ROS to destroy invading pathogens?

neutrophils and macrophages

What organisms require high pressure to grow?

Barophilic (piezophile)

What organisms love pressure in the ocean?

Barotolerant

Does Barophilic have larger or shorter fatty acids?

Shorter

Does Halomonas salaria (gram -) like pressure?

Not really, but they like salt.

What gram negative bacteria that require 14,794 psi (1006 atm) to grow?

Halomonas salaria

What is the highest amount of energy that causes damage to the DNA?

radio waves

what ionizing radiations do have a shorter amount of energy?

X-rays and gamma rays

What is the world's toughest bacterium in The Guinness Book Of World Records? What is its characteristics?

Deinococcus radiodurans – multiple backups (share the backup copies)

What radiation have shorter wavelength? Ionizing or Non-ionizing?

Ionizing radiation

What radiation have lower energy? Ionizing or Non-ionizing?

Non-ionizing

What is the primary pigment used by cyanobacteria for photosynthesis?

Chlorophyll

Which pigment in cyanobacteria serves a photoprotective role?

Carotene

What is the function of gas vacuoles in cyanobacteria?

Buoyancy control

Which accessory pigments assist in light absorption in cyanobacteria?

Phycocyanin and phycoerythrin

Do microbes depend on others and sometimes act the same?

Microbes depend on each other but sometimes they will act differently

Microbial environments are …………., constantly changing, often contain ………. nutrient concentrations and may expose a microorganism to ………. gradients of nutrients and environmental factors

complex…….low……overlapping

Where are biofilms found?

In hard surfaces