Micropara midterms Flashcards
Microbial Growth and Reproduction
Identify the cell division of the following bacteria:
Conventional bacteria
Binary Fission
Identify the cell division of the following bacteria:
Pirella, Blastobacter
Simple budding
Identify the cell division of the following bacteria:
Hyphomicrobium, Rhodomicrobium, Pedomicrobium
Budding from hyphae
Identify the cell division of the following bacteria:
Caulobacter
Cell division of stalked organism
Identify the cell division of the following bacteria:
Rhodopseudomonas, Nitrobacter, Methylosinus
Polar Growth without differentiation of cell size
The increase in number of individual cells or population in a culture is expressed in the algebraic expression ________
1x2^n where n = no. of generation
Time interval required for each microbe to divide or for the population to double
Generation time (Doubling Time)
Gen Time (g) formula
t/n
Growth rate (R) formula
n/t = 1/g
Final population beginning with 1 cell formula
N = 1x2^N
No. of Generations for inoculation culture starts in the magnitude of thousands formula
Nox2^n
No is the initial population
log10 N- log10N0/ log102
Identify the growth phase from the growth rate and characteristics:
Zero
No increase in cell no.
Cells inc in size
Cells physiologically active and synthesizing new enzymes to adapt to new environment
Lag
Identify the growth phase from the growth rate and characteristics:
Maximal and constant
Balanced growth
cells most nearly uniform
peak time of physiological activities
Exponential or Logarithmic (Log)
Identify the growth phase from the growth rate and characteristics:
Zero
Accumulation of inhibitory metabolic products and depletion of nutrients
Some cells divide others grow and die
Stationary
Identify the growth phase from the growth rate and characteristics:
Negative
Further accumulation of inhibitory metabolites and depletion of nutrients
Death rate accelerates
Viable cells decreases exponentially
Death
Identify the Measurement of microbial growth:
Measures count of living cells
Colony forming unit (CFU)/ml
Serial dilution is usually applied
Viable Count
Identify the type of viable count method by the formula:
CFU/ml = ave # of colonies x dilution factors/ Volume plated (0.1ml)
Spread Plate
Identify the Measurement of microbial growth:
CFU/ml = ave # of colonies x dilution factor/ Volume plated (1.0ml)
Pour plate
Identify the Measurement of microbial growth:
Measures count of both living and dead cells
Cells/ml
Direct Count
What is the formula for direct count
Cells/ml= (number of cells in 5 squares) (50,000) (dilution factor)
Identify the Measurement of microbial growth:
Makes use of spectrophotometer
Optical density or absorbance units
Applicable in liquid samples
Turbidimetric Method
Identify the Measurement of microbial growth:
Applicable in liquid samples
Living cells are counted
Colony forming unit (CFU)/ml
Membrane Filter Method
Identify the Measurement of microbial growth:
g/g of sample
Dry weight
Identify the Measurement of microbial growth:
Indirect measurement
mg or microgram nitrogen/g of sample
Nitrogen Content
Identify the method of isolation of microorganisms into pure culture:
Arises from a single cell or spore or form a group of the same microorganisms attached to one another in clumps or chains
Colony
Identify the method of isolation of microorganisms into pure culture:
A culture consisting of a single species of microorganism
Pure culture
What are the 3 types of pure culture methods?
- Streak-plating method
- Spread-plating method
- Pour- plating method
Transport processes so slow that growth cannot occur
Membrane gelling (minimum)
Collapse of the cytoplasmic membrane; thermal lysis
Protein denaturation (maximum)
Control of Microorganism
Methods of control
Physical Agents and Chemical Agents
What are the different physical methods of control?
- Moist Heat
- Dry Heat
- Low Temperatures
- Radiation
- Filtration
- Dessication
Identify the Moist Heat method:
121 C, 15 psi, 15-30 min
Sterilizing instruments, linens, utensils, treatment trays, media, other liquids
Ineffective against organisms in materials impervious to steam; can’t be used for heat-sensitive articles
Autoclave
Identify the Moist Heat method:
100 C
Killing vegetative cells on instruments, containers
Endospores are not killed; can’t be relied upon to sterilize
Boiling Water
Identify the Moist Heat method:
62.8 C, 30 min or 71.7 C, 15 min
Killing vegetative cells of disease-causing microorganisms and of many other organisms in milk, fruit juices, and other beverages
Pasteurization
Identify the Dry Heat:
170-180 C, 1-2 hrs
Sterilizing materials impermeable to or damaged by moisture, e.g. oils, galss sharp instruments, metals
Destructive to materials that cannot withstand high temperatures
Hot-air Oven
Identify the Dry Heat:
hundreds of C
Sterilization of transfer loops and needles; disposal of carcasses of infected animals; disposal of contaminated objects that cannot be reused
Incineration
Identify the Dry Heat:
Less than 0 C
Preservation of foods and other materials
Mainly microbiostatic instead of microbicidal
Freezers
Identify the Dry Heat:
-196 C
Preservation of microorganisms
High cost of liquid nitrogen
Liquid-Nitrogen refrigerators
Identify the type of Radiation:
Gamma rays and X-rays
Drive away electrons and split molecules
Able to penetrate packaging and products and sterilize their interiors (packaged food, medical equipment, commercial machines)
Difficult to control due to emission of isotopes
Ionizing Radiation
Identify the type of Radiation:
Ultraviolet rays
Excites electrons; damages DNA
Used to reduce number of microorganisms in air and on surfaces (hospitals, aseptic rooms where sterile products are being dispensed)
Impenetrable to materials
Non-ionizing radiation
Identify the membrane filters:
Used to sterilize fluids by removing microorganisms
Membrane Filters
Identify the type of Radiation:
Used to remove or reduce the number of microorganisms in air to prevent their spread in laboratories and hospital environments
e.g. biosafety cabinet
High-Efficiency Particulate Air (HEPA) Filters
Are used as prefilters and for the filtration of liquids with a high amount of suspended particles
Depth filters
Are used in many applications in the laboratory and in industry because they are readily available in a wide variety of sizes and porosities, economical, and applicable to nearly all filtration needs
Membrane filters
Identify the type of physical method of control:
By light
By temperature
By moisture
By lyophilization
By high concentrations of salt or sugar
Dessication
Lyophilization is also called
Freeze drying or preservation of cultures
Identify The commonly used disinfectants and antiseptics:
0.5-3.0% aqueous solution
Disinfection of inanimate objects such as instruments, floor and table surfaces, and rectal thermometers
Phenol and Related Compounds
Identify The commonly used disinfectants and antiseptics:
70-90%
Disinfection of skin, delicate surgical instruments, thermometers
Denatures proteins and disrupts cell membranes
Alcohols
Identify The commonly used disinfectants and antiseptics:
1.0-2.0%
Disinfection of skin, minor cuts, and abrasions; also used for disinfection of water and swimming pools
Oxidizes cellular constituents
Iodine
Identify The commonly used disinfectants and antiseptics:
0.5-5.0g available chlorine per liter
Disinfection of water nonmetal surfaces, dairy equipment, restaurant utensils, household items
Oxidize cellular constituents
Chlorine Compounds
Identify The commonly used disinfectants and antiseptics:
0.1-0.2%
Environmental sanitation of surfaces and equipment
Disrupt membranes and denatures proteins
Quarternary Compounds
Identify The commonly used disinfectants and antiseptics:
1.0%
Disinfection of skin, instruments; also used as a preservative in some biological materials
Bacteriostatic agents
Mercurial Compounds
Identify the different evaluation of antimicrobial Potency of Disinfectant and Antiseptics
Tube-Dilution Technique
Agar-Plate Technique
Phenol-Coefficient Technique
Highest dilution of phenol that kills the microorg after 10 min but not after 5 min/ highest dilution of test chemical that kills the microorg after 10 min but not after 5 min
Phenol Coefficient
The Diversity of the microbial world
A manual or book where you can Consult the description of a particular genus or species of bacteria
Also provides a practical arrangement for differentiation microorganisms, together with appropriate outlines and tables
An international reference work resulting from cooperative efforts of hundreds of
Bergey’s Manual of Systematic Bacteriology
What are the 3 domains of living organisms based on sequence of nucleotides in rRNA
Bacteria, Archaea, Eukarya
Identify the components of a Eubacteria:
Cell wall:
Phospholipids in cell membrane:
Protein synthesis:
Cell wall: Peptidoglycan
Phospholipids in cell membrane: Long chain fatty acids
Protein synthesis: Formylmethionine
Identify the components of a Archaeobacteria:
Cell wall:
Phospholipids in cell membrane:
Protein synthesis:
Cell wall: Proteins or Polysaccharides
Phospholipids in cell membrane: Long chain branched alcohols (phytanols)
Protein synthesis: Methionine
In Bacteria and Eukarya Lipids contain fatty acids bonded by _____ to glycerol
Ester linkages
In Archaea, the side chains are branched hydrocarbons bonded by _____ to glycerol
Ether linkages
Is synthesized from isoprene
Phytanyl
Two types of Eubacteria
Cell wall present and Cell wall absent
What are the types of Eubacteria with cell walls
Gram-positive
What is the type of eubacteria with cell wall absent
Mycoplasmas
What are the different types of Archaeobacteria?
Methane producers
Red extreme halophiles
Sulfur-dependent archaeobacteria
Thermoplasmas
What are the different gram-negative bacteria?
Spirochetes
Aerobic or microaerophilic curved rods
Aerobic rods and cocci
Facultative anerobic rods
Anaerobes
Rickettsias and Chlamydias
Anoxygenic phototrophs
Oxygenic phototrophs
Gliding bacteria
Sheathed bacteria
Budding and/ or appendaged bacteria
Chemolithotrophs
What are the different gram-positive bacteria?
Cocci
Endospore-formers
Regularly shaped rods
Irregularly shaped rods
Mycobacteria
Actinomycetes
- Assume different shapes
- Have cholesterol in cell membrane
- Filterable
- Swell and burst when suddenly diluted with water
- Not inhibited by penicillin
-inhibited by other antibiotics that act on other cellular or metabolic processes - fried-egg appearance on agar
Mycoplasmas
What are the different Archaeobacteria
Methanogens
Red extreme halophiles
Sulfur-dependent
The green color of seawater is primarily from cells of the halophilic green alga ______
Dunaliella salina
The red-purple color in the California and a series of seawater evaporating ponds where solar salt is prepared is predominantly due to bacterioruberins and bacterioshodospin in cells of
Halobacterium
An archaeobacteria with no cell wall like mycoplasmas but grow at high temp, cells disintegrate at ph 7, and is isolated from piles of burning coal refuse
Thermoplasmas
Sulfur-rich hot spring, a habitat containing dense populations of _____
Sulfolobus
Microscopic Fungi
Chemoheterotrophs
Absorptive
Saprophytics
Multicellular except for yeasts
Undergo alternation of generation in life cycle
Posses sexual and asexual spores
Cell walls: Chitin; Glucans; Mannans
Fungi
What are the Life cycles stages and their types?
Asexual stage
- fragmentation
- budding
- producing spores
Sexual Stage
- Homothallic Mycelia
- Heterothallic Mycelia
Identify the Major Distinguishing Characteristic of Fungi from the description:
Cellular slime molds
Acellular slime molds
Division Gymnomycota
Identify the Major Distinguishing Characteristic of Fungi from the description:
Motile cells through flagellum
Division Mastigomycota
Identify the Major Distinguishing Characteristic of Fungi from the description:
Non-motile cells
Zygomycetes, Ascomycetes, Basidiomycetes, Deuteromycetes
Division Amastigomycota
In Zygomycetes, a type of amastigomycota (bread molds), zygote is transformed into a thick-walled _____; vegetative reproduction by _______
Zygospore, sporangiospores
In Basidiomycetes (club fungi, mushroom), a type of amastigomycota, sexual spores produced outside on club-like cells are called
Basidia
In Ascomycetes (Sac molds), a type of Amastigomycota, sexual spores produced inside a sac-like ____ typically produced in ascocarp; vegetative reproduction by _____. Includes yeasts and molds.
Ascus, Conidia
In Deuteromycetes (fungi imperfecti), a type of amastigomycota, sexual reproduction _____; vegetative reproduction by ____ arising from well-defined conidogenous cells
unknown, conidia
(Memorize table sa microscopic fungi)
Filamentous, multicellular with fuzzy or cottony appearance
Molds
Type of mold that is a mass of filaments that branch and intertwine forming a mass
Mycelium
Type of mold where only a few are septated and contains numerous nuclei and exhibit protoplasmic streaming
Hyphae
What are the 2 types of Hyphae
Vegetative hyphae - secures nutrients and anchor organism
Fertile hyphae - extends into the air and bear reproductive bodies
Identify the type of asexual spore:
Spore resulting from hyphal fragmentation
Geotrichum
Arthrospore
Identify the type of asexual spore:
Hyphal cell, enveloped by a thick wall, that eventually separates from the parent hypha and behaves as a resting spore
Fusarium
Chlamydospore
Identify the type of asexual spore:
Motile spore
Olpidium
Zoospore
Identify the type of asexual spore:
Spore borne w/n a sac at the end of a fertile hypha of a nonseptate mold
Rhizopus
Sporangiospore
Identify the type of asexual spore:
Exposed usually found at the tip/ side of hypha
Penicillium
Conidium
Identify the type of sexual spores:
Spore borne in an ascus
Ascospore
Identify the type of sexual spores:
Spore borne outside of a basidium
Dacrymyces
Basidiospore
Identify the type of sexual spores:
Thick walled spore developed from an oosphere w/c is very resistant to drying and can remain dormant for a long time
Monoblepharis
Oospore
Identify the type of sexual spores:
Spore resulting from the fusion of 2 gametangia in zygomycetes
Mucor
Zygospore
Identify the Characteristic of Spore heads:
Sac-like structure containing spores
Rhizopus
Sporangia
Identify the Characteristic of Spore heads:
Hyphal branches/structures supporting conidia/basidiosphores
Penicillium
Sterigmata
These are stalk-like hyphal structure to w/c the spore heads are attached
Sporangiophores/Condiophores
Identify the special structure:
A hypha w/c connects 2 groups of rhizoids
Stolon
Identify the special structure:
Root-like thallus branch w/c anchors the mold to the substrate
Rhizoid
Identify the special structure:
Hyphal cell w/c branches to give rise to the conidiophore
Foot cell
Identify the special structure:
hard, resting body w/c is resistant to unfavorable conditions and can remain dormant and germinate upon the return of favorable condition
Sclerotium
First observed that colonies of staphylococcus aureus failed to grow in a culture contaminated by the green mold. Also produces penicillin
Penicillium notatum
What is the Heirarchy of Classification for Penicillium Notatum
Kingdom: Fungi
Phylum: Ascomycota
Class: Leotiomycetes
Order: Helotiales
Family: Sclerotiniaceae
Genus: Penicillium
Species: notatum
Unicellular, may be spherical, elliptical/cylindrical
Asexual by budding, sometimes sexual associated with ascospore formation
Yeasts
Filamentous structure resulting from the continuous growth of hyphal tip
True mycelium/hyphae
Filamentous structure arising from mature buds w/c doesn’t detach from the mother cell
Pseudomycelium/pseudohyphae
Has true mycelium/hypae and Psedomycelium/pseudohyphae and causes candidiasis
Candida albicans
Different shapes of Yeasts
Ovoid - Torulopsis versatilis
Elongate - Candida tenuis
Cylindrical - Candida utilis
Ellipsoidal - Brettanomyces bruvellensis
Subglobose - candida lusitaniae
Apiculate - Kloeckera apiculata
Vegetative cells
Multipolar budding - Saccharomyces cerevisiae
Bipolar budding - Kloeckera apiculata
Fission - Schizoaccharomyces
Unipolar budding - Malassezia furfur
Ascus and Ascospore
Hat-shaped ascospore - hansenula anomala
Spherical Ascospores - saccharomyces cerevisiae
Needle-shaped ascospore - Metschinikowia vanudenii
Reniform ascospores - Kluyveromyces delphensis
Labster Bacterial Growth Curves
What technique could you use to quantify the number of viable bacteria at different time points?
Serial dilution and colony count
How would you write this growth by cell division in a mathematical equation? N stand for the number of cells at a certain time t, n stands for the number of generations.
Nt = 2^n * N0
How did we get from a few thousand cells to more than a million?
Doubling by cell division.
We could use the magic of math to save this plot! What function would help you visualize all the values on the same plot and show that the bacteria were growing between each of the measurements?
Take logarithm of measurements
The straight line indicates that there is a constant growth rate. This growth rate is defined as k. What is it actually describing? Thank about what is constant in binary fission.
Generations per time
What is the formula for the growth rate constant k? Remember n refers to the generations time and t represents the time.
K = n/t
Now that you are juggling formulas like a pro, let me ask you time: How could you combine the growth rate k = n/t and the growth formula Nt = 2n *N0 form before?
K = log2(Nt/N0)/t
Why does the last point not line up with the rest?
Limited resources
What happens once all the nutrients are used up?
The number of viable cells will decrease
Why do you think there is a lag before the bacteria cells start growing?
Bacteria cells adjust to the growth medium
What features relates to the growth rate k of the growth of the two bacterial cultures?
The slope of the exponential phase
What is formula for the slope m of the exponential phase?
M = log10(Nt/N0)/t
How does the growth rate k and the slope m relate to each other? K = log2(Nt/N0)/t ; m = log10(Nt/N0)/t
K = m / ~0.301
How does the fungal compound affect the bacterial growth?
The fungal compound reduces k
What other factors could influence the growth rate?
Temperature
Well done! What is your hypothesis (temperature set to 45 Celsius)
The bacteria in the incubator will grow faster than the ones at room temperature.
Labster Control of Microbial Growth
According to the theory, why is it important to know how much of a pathogenic risk an item poses to an end-user?
The risk determines how you must decontaminate an item so that the next user doesn’t get infected
We’ve got a probe and a kidney dish. The probe was used to explore the patient’s teeth, so will have contacted the patient’s mucous membranes and the outside of their teeth. What classification would you give to the dish and the probe if they were used as per their normal intended processes?
Both would be semicritical
Based on your exploration and the theory, what do you think the difference is between decontamination and sterilization?
Sterilization is a type of decontamination, but not all decontamination techniques result in true sterilization.
Now that you’ve explored the lab and found what you’ve got on hand to work with, what do you think the first step should be for decontamination these tools?
We should remove loose soil and debris by washing using a biological detergent.
Based on your explorations and theory reading in the lab today, which sterilization method do you think would be best for these items?
Steam and high pressure will kill everything; let’s use the autoclave.
How does wet heat sterilization work to inactivate bacteria and other infectious pathogens?
The sustained heat and pressure denatures proteins, without proteins nothing can replicate or remain infectious
What do we highlight when we talk about antimicrobial resistance?
The ability of a microbial strain to withstand the effects of a previously effective antimicrobial agent.
When we say an antimicrobial agent exhibits ‘selective toxicity’, what do we mean?
The agent is only toxic to microbial cells because it targets a cell component only found in microbes and not present in the host organism
Why do we need a positive control in this experiment?
The hypochlorite is known to cause inhibition, so shows inhibition can occur in the current experiment and what it looks like; this is the positive control.
How many zones of inhibition have formed on the plate?
2
What tentative interpretation can you make from what you observe?
The penicillin has failed to make a zone despite the positive control’s success. The bacteria may be resistant to penicillin.
Why do you think penicillin has failed to destroy the bacteria we have cultured from the patient’s sample?
Perhaps a few cells from the old infestion developed resistance and so weren’t cleared by the previous treatment. They could have gone on to develop this second abscess.
According to the theory, how does penicillin kill bacteria?
Penicillin targets a cross-linking reaction in cell wall manufacture. By blocking the enzyme responsible, penicillin stops the bacteria from producing new peptidoglycan.
It seems that the new infection has a different form of the transpeptidase enzyme that penicillin can’t bind to - what a sneaky resistance mechanism! What is one other way suggested by theory by which a previously sensitive bacterial strain can become resistant to penicillin?
Bacteria can express an enzyme capable of inactivating penicillin before it can bind to transpeptidase
The drug you added seemed to prevent cell growth much quicker, but the cells didn’t burst like before. According to the theory, why do you think clindamycin and metronidazole produce a different effect to penicillin?
Metronidazole targets the DNA of microbial cells and clindamycin targets the ribosome. neither of wich create a lytic effect like penicillin.
Even if resistance was not an issue, antimicrobials would only have a discreate range of bacteria that they can exert their effects on. Why do you think this is?
Microbial components vary over different species and strains. If the organism naturally doesn’t express the target component, the drug won’t be able to exert an effect on it.
Did you learn anything about bacteria causing the infection?
We conducted a diffusion disc assay, the new infection was not inhibited by a penicillin challenge. Maybe the new infection is penicillin-resistant?
Is there anything else that might help them?
Chlorhexidine is an effective antiseptic at the right concentration, maybe they could try this as a mouthwash?
How did you get on with the tools? How did you process them?
We cleansed them using biological detergent then rinsed and dried everything before autoclaving.
