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Microbial growth and antibiotics > Microbial growth and antibiotics > Flashcards

Microbial growth and antibiotics Flashcards

1
Q

What is 4 types of shape in bacteria?

A

Cocci(こかい) - spherical

Bacilli(バチリ) – rod shape

Spirilla(siフィリア) – spiral shaped

Vibrio(ビブリオ) – curved shape

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2
Q

What is examples of cocci?

A

Staphylococcus aureus

Diplococcus pneumoniae

Streptococcus pyogenes

S.thermophilus

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3
Q

What is examples of bacilli?

A

Salmonella typhi

Escherichia coil

Azotobacter

Bacillus anthracis

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4
Q

What is examples of spirilla?

A

Spirillum rubrum

Treponema pallidum

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5
Q

What is examples of vibrio?

A

Vibrio cholerae

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6
Q

What is difference between prokaryotes and eukaryotes?

A

No nucleus vs Nucleus

Circular DNA vs linear DNA

No membrane bound organelles vs Membrane bound organelles

No endoplasmic reticulum vs Endoplasmic reticulum

No golgi body vs Golgi body

No mitochondria vs Mitochondria

No organised chloroplasts vs Chloroplasts in photosynthetic cell

Mesosome vs No mesosome

70s ribosome vs 80s ribosome

1 – 10 nanometer vs 10 – 100 nanometer

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7
Q

What is structure all bacteria have?

A

Cell wall

70s ribosome

Food reverse granule

Cell surface membrane

Cytoplasm

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8
Q

What structure is sometimes present in bacteria?

A

Mesosome

Circular DNA
pili

Photosynthetic membranes

Flagellum

Capsule layer

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9
Q

What is cell wall?

A

Rigid structure for shape

Made of murein(peptidoglycan)

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10
Q

What is gram staining?

A

Classify bacteria as gram positive or negative

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11
Q

What is gram positive?

A

A cell wall is gram positive if 40% to 95% is murein

Identified by purple stain on gram staining

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12
Q

What is gram negative?

A

A cell wall is gram negative contain as little as 5% murein

Don’t retain crystal violet

Stained red if counter stain used

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13
Q

What is mesosome?

A

Infolding of cell membrane

Contain enzymes involved in respiration

Aid cell division during separation of DNA into new cell

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14
Q

What is circular DNA?

A

Contain genetic info

Has zone called nuclear zone

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15
Q

What is pili?

A

Used in reproduction

Similar to flagellum

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16
Q

What is 70s ribosome?

A

Smaller ribosome

Involved in translation at protein synthesis

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17
Q

What is photosynthetic membranes?

A

Infold membrane

Contain photosynthetic substance

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18
Q

What is food reserve granule?

A

Contains food source e.g. polysaccharides

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19
Q

What is flagellum?

A

Made of flagellin

Gives mobility

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20
Q

What is cell surface membrane?

A

Made of phospholipid bilayer and protein

Selectively permeable

Controls what in and out

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21
Q

What is capsule?

A

Mainly polysaccharides and some polypeptide

Protection against phagocytosis and antibiotics

Prevents dehydration

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22
Q

What is plasmid?

A

Pieces of DNA

Contain few genes

Beneficial effects e.g. antibiotic resistance

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23
Q

What is process of Binary fission?

A

Cell elongate, DNA replicate then attaches to mesosome

A septum synthesised to divide

Septum grow across dividing the genetic material

Cytokinesis happens

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24
Q

What is called time bacteria population require to double?

A

Generation time

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25
Q

What is equation for binary fission?

A

2n

n is generation

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26
Q

2 ways for cell to obtain energy?

A

Obtain light

Oxidise chemical compound

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27
Q

What is photoautotrophs?

A

Use co2 in photosynthesis

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28
Q

What is photoheterotrophs?

A

Use organic source in photosynthesis

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29
Q

What is chemotrophic bacteria?

A

Obtain energy using chemical compound

They break down compound leading to production of ATP

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30
Q

What is chemoautotrophic bacteria?

A

Obtain energy by oxidising inorganic compound

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31
Q

What is chemoheterotrophic bacteria?

A

Obtain energy by oxidising organic compound

Most of bacteria

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32
Q

2 types of bacteria growth method in lab?

A

Batch culture

Continuous culture

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33
Q

What is growth phases in typical growth curve?

A

Lag phase

Log/exponential phase

Stationary phase

Death phase

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34
Q

What is lag phase?

A

No or little cell division

But cell may increase in size

Synthesise RNA, proteins and enzymes

Nutrient specific enzymes might be produced

If bacteria used to environment, it might get shorter

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35
Q

What is log phase?

A

Cell at maximum division rate

All condition optimal for growth

No limiting factor

Primary metabolite formed and excreted

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36
Q

What is stationary phase?

A

No increase in population

Limiting factor appeals

Secondary metabolites which is not essential might be produced and excreted

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37
Q

What is death phase?

A

Unfavourable condition increase so death rate above growth rate

Autolysis may often occur

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38
Q

What effect does temperature have on bacteria growth?

A

Low temp – slow due to low kinetic energy reducing enzymes activity on metabolism

High temp – most bacteria gets destroyed as enzymes denature

Extremophile may be adapted

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39
Q

What effect does pH have on bacteria growth?

A

Extremely high or low pH would cause denature of enzymes required for metabolism

40
Q

What effect does O2 concentration have on bacteria growth?

A

Depends on microbe type

If obligate aerobes high concentration is ideal

If obligate anaerobes low concentration is ideal

41
Q

List types and properties of microbes in relation to their O2 preferences?

A

Obligate aerobes – live only when O2 present

Obligate anaerobes – live only when no O2 present

Facultative anaerobes – can live in both, prefers O2 present

Aerotolerant anaerobes – prefers anaerobic but can live with O2

Microaerophiles – anaerobic condition required but low O2 concentration is fine

42
Q

Name all types of extremophiles?

A

Halophiles

Alkalinophiles

Acidophiles

Barophiles(Piezophile)

Thermophiles

Psychrophiles

43
Q

Halophiles?

A

Survive in high salt conc

High conc of salt in cytoplasm preventing osmosis out of cells

Optimal folding proteins tolerating high salt conc

Cell wall is composed of glycoprotein and stabilised by sodium ions

44
Q

Alkalinophiles?

A

Optimal in pH above 9.0(Alkali)

Membrane and cell wall resist dissolution

Adapted proteins

Intracellural pH close to 9.0

Actively pump hydrogen ions in to use ATP synthase

45
Q

Acidophiles?

A

Optimal in below pH 5.0

Acid resistant cell walls and membranes

Activelly pump out excess protons

46
Q

Barophiles

A

Preferably or exclusively at high hydrostatic pressure

Barotorelant - high to 500 atmosphere

Barophilic - requires high pressure, usually at 700, 800 atmosphere, not less than 400 atmosphere

Increased pressure decrease binding capacity, so enzymes must be folded in such a way to minimise this

Lipid bilayer is more tightly packed so provide more rigid structure and shields the inside

ompH gene code for a protein at high pressure but inhibited at low, so enables uptake of wider range of nutrients

47
Q

Thermophiles?

A

Optimum above 45 celcius

If above 80 celcius is hyperthermophiles

High saturated fatty acid in membrane for stability

More chemical bonds to maintain protein shape

Loops of polypeptide less or absent

Less amino acids unstable at high temp

Chaperones refold denatured proteins

DNA use DNA-binding proteins and reverse DNA gyrase to introduce supercoils into DNA

48
Q

Psychrophiles?

A

Optimal at 15 celcius or below

Cold adapted enzymes

Increase in unsaturated fatty acid as temp reduce to control membrane fluidity

Antifreeze protein bind to ice ctrystal preventing piercing of membrane

49
Q

What is 2 methods used to estimate cell number in microbal population?

A

Total cell count(death and living cell)

Viable cell count(living cell)

50
Q

What is haemocytometry and describe?

A

Total cell count

Use chamber as haemocytometer

Volume is 0.004mm3

Well mixed sample diluted

Then counted, averaged and using dilution factor estimated

51
Q

What is turbidimetry and describe?

A

Total cell count

Use colorimeter

Culture medium become more turbid(cloudy) as cell increase

Culture is well mixed before measure

Optical density measured

Cannot differentiate living and death

52
Q

Dilution plating?

A

Variable cell counts

Dilution factor calc is done to liquid culture

Done aseptically

53
Q

Fungi properties?

A

Eukaryotic

Some can be unicellular

They are heterotrophic(use organic matter)

They can be parasitic, mutualistic or saprophytic

Use extracellular digestion

54
Q

Filamentous fungi properties?

A

Fine, branched thread called hyphae

Hyphae forms mass called mycelium

55
Q

What is structure of fungi?

A

Cell wall made of chitin

Same as other eukaryotes

Some are coenocytic, so no cross wall between each other

56
Q

What is name of 2 methods used for measure of fungi growth?

A

Increase in diameter mycelium - only on filamentous fungi

Increase in dry mass - any microorganism

57
Q

Describe how to measure increase in diameter of mycelium?

A

Used in filamentous fungi

If effect of temperature on the growth measured:

Agar plates containing identical concentration of nutrients are
inoculated with the same quantity fungi

Obtain equal sized pieces of mycelium, place in the centre of each plate

Each plate is incubated at a different temperature in the range

All other environmental conditions are standardised e.g. nutrient concentration and pH

The increase in the diameter of the mycelium is measured and recorded daily

These results can be plotted on a graph and the optimum temperature determined

58
Q

Describe how to measure increase in dry mass?

A

Used in microorganisms

If the effect of pH on the growth rate of a
filamentous fungus measured:

Set up flasks containing liquid broth media of the same volume and nutrient concentrations

Inoculate each flask aseptically with the same mass of fungal mycelium

Each culture is incubated at a different pH using buffers

Ensure temperature is standardised and at the optimum

At suitable time intervals, remove an identical volume of sample
from each culture and determine the dry mass of fungus in pH culture.

The dry mass is determined by placing the sample in an oven until all the water is removed.

Dry mass at each pH can be plotted on a graph and the optimum pH for the growth of that particular fungus determined.

For oven, heat at 100°C for an hour, remove and weigh it.
Reheat for 15 minutes and reweigh it until you get two constant masses

59
Q

List source of contamination in experiment?

A

Non-sterile apparatus

Air

Skin surface

Work surface

60
Q

List aseptic techniques to prevent contamination?

A

Use sterile syringes/pipettes/equipment

Flame top of test tube/bottle/inoculating loops

Minimise exposure to the air by lifting lid of dish lightly

Avoiding sterile apparatus touch skin or work surface

61
Q

How should a culture media be prepared?

A

Maybe solid or liquid

They must contain balanced mixture of required nutrients

So desired species grow

62
Q

What is phototrophic bacteria?

A

Obtain energy via light during photosynthesis

Light utilised by pigment e.g. bacteriochlorophyll

63
Q

How and why should complete/Complex media be prepared and used?

A

Used for wide range of microorganism growth or when no exact nutrients are known

It cantains all nutrients required for growth e.g. glucose, amino acids, water, salts, vitamins, trace elements

64
Q

How and why selective/minimal media?

A

Suitable for growth of specific microorganism

If inoculated with mixed culture, only species the medium designed for will grow

Growth of others will be supressed

Condition would also be for specific spicies

65
Q

How can sterilise specific equipment?

A

Direct heating - Inoculating loop, neck of tubes

Autoclaving - glassware, unwanted culture

Burning alcohol - glass

Disinfectants - inanimate objects

Ultrafiltration

66
Q

Why do we use streak pleating?

A

To obtain pure culture from mixed culture of bacteria

67
Q

Streak plateing method?

A

Use inoculating loop to move bacteria to agar plate

Lift the lid of petri dish slightly to minimise air exprosure

Streak the agar plate with sample

Reflame loop

Re-streak sample on plate at right angle from last time

Incubate the plate at 25 degrees celcius for 2 days

During exam include asepctic technique and how it prevent contamination of the culture

68
Q

What is sub-culturing?

A

Using aseptic technique pick and transfer a sample from a single colony onto another agar plate and incubate

69
Q

What is bioassay?

A

Determines the effectiveness of a compound by seeing compound effect on growth of microorganism

Also used to screen microorganism to determine for antibiotic prodcution

This is by measuring their ability to inhibit the growth of bacteria on a bacteria lawn

70
Q

What is antibiotics?

A

Compound produced by microorganims inhibiting or killing bacteria

Can work in either in bacteriostatic or bactericidal

In natural enviroment, fungus antibiotic is ecological advantage as reduce competition

71
Q

How does bacteriostatic work?

A

Inhibits or prevent bacteria growth

72
Q

How does bacteriocidal work?

A

Actually kill the bacteria

73
Q

Bioassay screening method for specific fungus to specific bacteria?

A

Take an agar plate seeded with bacteria

Place a mycelial disc from the fungus onto centre of agar

Incubate the plate

If the antibiotic produced by fungus is effective against bacteria then a clear zone will result

Clear zone represents inhibition of growth or death of bacteria

Larger the diameter, the more effective

74
Q

What is bioassay method for semi-synthetic antibiotics or synthetic antibiotics?

A

Take an agar plate seeded with the test bacterium

Then place a standard volume of antibiotic into a standard sized well or use standard sized paper discs with
antibiotic

Incubate at 25 degree celcius for 48 hours

A clear zone will be produced if the antibiotic is effective against the bacteria

75
Q

What is disinfectant?

A

Chemical compounds that kill bacteria, e.g. Lysol, Dettol

It is possible to determine the effectiveness of a disinfectant by using bioassay

76
Q

What is antibiotics?

A

Chemical substances produced by microorganisms or synthetically

It inhibit the growth of or kill other microorganisms

Usually bacteria but few are effective against fungi

They are ineffective against viruses

77
Q

4 ways antibiotics work?

A

Inhibiting cell wall synthesis

Cell membrane disruption

Inhibiting mRNA translation

Inhibiting nucleic acid synthesis

78
Q

What antibiotic inhibits cell wall syntheis and how?

A

Penicillins and Ampicillin

Inhibits enzymes involved in the syntheis of peptide cross links in the cell wall, causing it to weaken

So burst as osmotic lysis happens

79
Q

What antibiotic disrupts cell membrane and how?

A

Polymyxin B

Alters cell membrane structure making it more permeable and leading to cell death

80
Q

What antibiotic inhibits mRNA translation and how?

A

Streptomycin and tetracyclines

Inhibit protein syntheis by biding across ribosomes but not on eukaryotic cell

81
Q

What antibitoc inhibits nucleic acid syntheis and how?

A

Ciprofloxacin

Inhibits DNA replication

82
Q

What is broad spectrum antibiotics?

A

Effective against a wide range of bacteria

May be initially used in the treatment of undetermined bacterial infections e.g. Tetracyclines

83
Q

What is narrow spectrum antibiotics?

A

Effective against a small specific group of bacteria e.g. Streptomycin is used to treat infections caused by streptococcus bacteria

Some antibiotics produce allergic effects in certain individuals

84
Q

Give examples of antibiotic resistance?

A

Penicillin resistance occurs as bacteria gets genetic mutation to produce enzymes penicillinase and breaks down penicillin

Mutation in change of biding site of antibitic

85
Q

How can bacteria gain antibiotic resistance?

A

Spontaneous mutation

Transfer of genes for resistance from other bacteria

86
Q

What is 2 ways of gene transmission?

A

Vertical and horizontal

87
Q

How does vertical gene transmission happens?

A

Resistance to antibiotics may arise due to a random mutation

Bacteria with resistance gene survive when exposed to the antibiotic

Bacteria reproduce and pass resistance gene on to future generations

Repeated exposure to antibiotics (particularly when dosages of antibiotic are not correctly administered or if the patient does not complete the full course of antibiotic) leads to more bacteria surviving and passing on the gene

Antibiotic resistant bacteria increase in the population lead to an increase in the frequency of the allele for antibiotic resistance

88
Q

How does horizontal gene transmission happen?

A

Antibiotic resistance gene are usually on plasmid, and plasmid can contain more than one antibitic resitance gene

The donor cell produces a conjugation tube (pilus) which connects the two bacterial cells

Horizontal gene transmission happens by conjugation

Donor cell replicates its plasmid and passes the copy of the plasmid to the other bacterium

The recipient cell receives the plasmid which may contain a gene for antibiotic resistance

89
Q

What is transduction

A

Can pass DNA of one bacteria to other bacteria

Bacteriophage insert its DNA to bacteria

Bacteriophage DNA replicates and host DNA splits into bacteriophage size

New bacteriophages made, some with original bacteriophage DNA some with bacteria DNA

Bacteriophage with bacterial DNA attacks another bacteria

Bacteria gains other bacteria DNA

90
Q

What is transformation?

A

DNA drom a lysed bacteria cell is bound to DNA binding protein in the host cell wall

One DNA strands enters host cell as other strand is broken down

The single strand of DNA is bound to the DNA of host cell

91
Q

Antibiotic resistance of tuberculosis?

A

Strain of bacterium Mycobacterium tuberculosis has resistance to different antibiotics due to mutation

Icomplete a course of antibiotic treatment enabled to survive and exchange their genes with other bacteria via horizontal gene transmission

So multiple-antibiotic-resistant strains of TB developed

So a cocktail of antibiotics is often used to treat TB

Scientists are trying to develop more effective antibiotics to treat TB and other bacterial infections

92
Q

Antibiotics resistance of MRSA?

A

MRSA (methicillin-resistant Staphylococcus aureus) is the name of any strain of the Staphylococcus aureus that is resistant to antibiotics

MRSA is difficult to treat and is prevalent in hospitals as:

Many antibiotics being used - enabling multiple-resistance to develop

Close proximity of patients - ideal for transmission of infections

Weak and sick individuals - more vulnerable to infection by MRSA.

93
Q

How is C.difficile infection happening?

A

When antibiotics is used in patients it decrease competition in body and increase and release toxin(Opportunistic bacteria)

94
Q

What is sympthoms of C.difficile infection?

A

Mild to severe diarrhea

Severe inflammation of the bowel

95
Q

Who is at risk in C.difficile infection?

A

People treated with broad spectrum antibiotics

People with serious underlying illnesses

Elderly

96
Q

How is C.difficile spread?

A

Hands of healthcare and other people in contact with patients or their enviromental surfaces contaminated with bacteria or spores

Spores are produced when bacteria encountered with unfavolable condition

They survive on clothes and surfaces for long period even when cleaned with alcohol

97
Q

What is treatment of C.difficile?

A

the use of specific antibiotics which will kill C. difficile (e.g. either metronidazole or vancomycin)

Probiotic supplements which are designed to stimulate the growth of ‘good’ bacteria (although the evidence of their effectiveness in treating CDIs is inconclusive)

Injections of immunoglobulins to enhance the production of antibodies available to fight off the infection

Fecal transplantation – this treatment involves transplantation of a fecal sample from a healthy donor

Serious infection may require surgery to remove a damaged section of the bowel.

Microbial growth and antibiotics (4 decks)

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