Term
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Definition
-energy emitted from atomic activities and dispersed at high velocity
-suitable for microbial control: Gamma rays, X-rays, Ultraviolet radiation |
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Term
Ionizing Radiation (γ and X-rays) |
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Definition
- radiation ejects orbital electrons from an atom, causing ions to form
- cause the most damage to proteins
- DNA breakage that can't be repaired |
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Term
Non-ionizing Radiation (UV) |
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Definition
- excites atoms, raising them to a higher energy state
- causes mutations of DNA by formation of abnormal bonds - pyrimidine dimers
- further interferes with normal DNA replication and transciption
- leads to inhibition of growth and death by apoptosis |
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Term
Effect of UV on Microbial Growth |
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Definition
- formation of thymine dimers within DNA caused by the absorption of non-ionizing UV radiation interfere with normal DNA replication
- typically leads to cellular death via apoptosis
- effectively kills bacterial vegetative cells
- effectively kills hyphae of fungi (takes more time than veg. cells)
- can even kill endospores but takes a lot of time
- nucleotide repair mechanisms can cause cells to recover from UV damage |
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Term
What cultures were used in the UV exposure lab? |
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Definition
- nutrient broth of S. marcescens
- nutrient broth of Bacillus cereus
- saline broth of Aspergillus niger
- nutrient broth of E. coli |
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Term
What are the two types of repair enzymes that exist? |
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Definition
- Photolyases: require light to excise the damaged nucleotides
- Endonucleases: work with or without light to excise damaged nucleotides |
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Term
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Definition
- the ability of bacteria to take up "naked" DNA from their environment |
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Term
What are the three ways for a cell to perform horizontal gene transfer? |
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Definition
- conjugation, transduction, and transformation |
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Term
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Definition
- the transfer of DNA from donor to recipient via a pilus |
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Term
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Definition
- the transfer of DNA from donor to recipient via bacteriophage |
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Term
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Definition
- a small circular DNA molecule within a cell that is physically separated from a (circular) chromosomal DNA and can replicate independently
- easily transferred between cells during conjugation and easily picked up by transformation
- can be genetically engineered and used in biotechnology |
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Term
What is the pGLO plasmid? |
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Definition
- an engineered plasmid used in biotechnology as a vector for creating genetically modified organisms
- possesses a Multiple Cloning Site (MCS) where genes of interest can be inserted
→→ GFP (green fluorescent protein), Ampicillin Resistance gene, araC gene |
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Term
What is GFP (Green Fluorescent Protein)? |
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Definition
- placed instead of genes for arabinose catabolism but its expression is regulated by ARABINOSE PROMOTER
- specifically, this gene will be expressed (transcribed) only in the presence of arabinose in media
- Aequorea victoria jellyfish gene
- genetic switch that regulates GFP gene transcription |
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Term
What is the Ampicillin Resistance gene? |
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Definition
- Beta-lactamase
- used to select only the bacteria that have taken up the plasmid
- since it codes for the enzyme beta-lactamase, only transformed bacteria will be resistant to ampicillin (beta-lactam antibiotic)
- Selective Agent used in lab |
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Term
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Definition
- regulates GFP transcription
- for DNA binding protein (also part of arabinose operon) that attaches to the promoter and acts like a switch for transcription of GFP |
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Term
What is used as the genetic switch to regulate expression of the GFP gene in transformed E. coli cells? |
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Definition
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Term
What is the ampicillin resistance gene? |
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Definition
- BLA (beta-lactamase) -- will inactivate ampicillin in petri dish
- transcribed to mRNA |
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Term
What does ELISA stand for? |
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Definition
- Enzyme-Linked ImmunoSorbent Assay |
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Term
What is the ELISA Test used for? |
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Definition
- uses antibodies and color change to identify specific organism that is causing the infection in patients sample |
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Term
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Definition
- a preparation of antigen attached to a solid support, which adsorbs (binds to) specific antibodies from a mixture of immunoglobulins |
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Term
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Definition
- a toxin or other foreign substance (protein) that induces an immune response in the body, especially the production of antibodies. |
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Term
What does it mean if a patient's sample is positive for the presence of antigens? |
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Definition
- the patient has an active infection |
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Term
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Definition
- a blood protein produced in response to and counteracting a specific antigen
- combine chemically with substances that the body recognizes as alien, such as bacteria, viruses, and foreign substances in the blood. |
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Term
What is propagated transmission? |
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Definition
- the spread of a disease from one person to another |
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Term
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Definition
- the first case of the disease in a population |
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Term
What is the morbidity (incident) rate? |
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Definition
- the number of new cases of a disease reported in a defined population in a given period of time |
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Term
What is the mortality rate? |
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Definition
- the number of deaths in a population in a given time due to a certain disease |
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Term
What are the three parts that make up blood? |
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Definition
- plasma: the liquid portion which contains water, proteins (like albumins & globulins), clotting factors, waste, salts, lipids, gasses, and nutrients
- cells: red and white cells
- platelets: cell fragments |
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Term
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Definition
- a way of looking at blood cells under the microscope for the presence of all different types of blood cells and the percentages that they are found in
- in a normal blood smear, red blood cells will appear as regular, round cells with a pale center
- a deviation from expected size/shape/values of red and white blood cells may suggest blood disorders |
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Term
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Definition
- red blood cells; the most abundant in the blood (40-45% of its volume)
- biconcave disk shape; anucleated |
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Term
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Definition
- granular and agranular white blood cells; all with nuclei |
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Term
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Definition
- platelets are cell fragments that help the blood clotting process (coagulation) by gathering at the site of an injury, sticking to the lining of the injured blood vessel, and forming a platform on which blood coagulation can occur |
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Term
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Definition
- Granular
- 2X the size of the RBC; purple cytosol; multi-lobed nucleus; pink granules in cytoplasm
- 55-90% of white blood cells
- general phagocytosis
- life span of 2 days, with only 4-10 hours spent in the circulation |
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Term
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Definition
- Granular
- similar to neutrophil; blue cytosol; large dark purple cytoplasmic granules that obscure the nucleus; deep blue granules in cytoplasm
- 0.5% of white blood cells
- active in allergy, inflammation, parasitic infections
- cytoplasmic granules contain histamines, prostaglandins, and other chemical mediators of the allergic response |
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Term
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Definition
- Granular
- similar to neutrophils; red cytosol; 2-lobed nucleus; red granules in cytoplasm
- 1-3% of white blood cells
- destruction of parasitic worms; mediators of allergy
- found in much higher numbers in the spleen and bone marrow |
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Term
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Definition
- Agranular
- 2-3X the size of a RBC; large indented kidney-bean nucleus; no granules
- 3-7% of white blood cells
- phagocytosis, followed by final differentiation into macrophages and dendritic cells
- also secrete several chemicals that moderate the functions of the immune system |
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Term
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Definition
- Agranular
- 2X the size of a RBC
- large round nucleus; no granules; thin rim of cytoplasm
- 20-35% of white blood cells
- specific (acquired) immunity
- 2 types exist; T cells are responsible for cell-mediated immunity; B cells are responsible for humoral immunity |
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Term
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Definition
- Biochemical test to identify organisms that produces catalase
- Enzymes within the ETC can alternatively form reactive oxygen toxins (hydrogen peroxide)
- Catalase converts hydrogen peroxide to water and oxygen
- creation of oxygen bubbles indicates presence of catalase |
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Term
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Definition
- Cytochrome c oxidase is a carrier within the ETC of some bacteria (reduces oxygen to water)
- test uses chromogenic reducing agent to detect the presence of the enzyme (if oxidase enzyme is present then it will oxidize CRA (instead of cyt. C in ETC) which will be indicated by the color purple)
- Purple +, clear - |
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Term
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Definition
- Differentiate between bacteria based on their ability/inability to reduce nitrate (NO3) to nitrites (NO2) or free nitrogen gas (N2) in anaerobic respiration
- Nitrate reduction occurs: 1. as a single step from NO3 to nitrite (NO2); 2. as a multi-step denitrification from NO3 to NH3 or N2 gas (both forms require nitrate reductase to convert NO3 to NO2
- Test for nitrate reductase require medium with NO3: Nitrate Reagent A (Sulfanilic acid) only reacts with NO2; Zinc can artificially convert NO3 to NO2 |
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Term
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Definition
• If the medium turns red after the addition of the Nitrate Reagents A&B, it is considered a positive result for nitrate reduction into nitrite
• If the medium does not turn red after the addition of the reagents A&B (10 dps each), it means one of two possibilities:
•Possibility 1: NO3 was not reduced to NO2, or
•Possibility 2: NO3 is reduced to NO2 , but reduction didn’t stop there and it went even further (until the production of reduced ammonia or molecular nitrogen)
• Therefore, another step is needed in the test. Add a small amount of powdered zinc. Development of red color indicates that unreduced nitrate was present (nitrate reduction didn’t happen (as in Possibility 1). Therefore, a red color on the second step is a negative result for the presence of nitrate reductase. No color development indicates that NO3 was reduced to NO2 and further reduced to NH3 or N2 (as in Possibility 2).
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Term
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Definition
•Differential Agent: Nitrate
•Primary Indicator: Nitrate Reagent A and Nitrate Reagent B
–Red = Nitrate Reductase (+)
–Clear = ???
•Secondary Indicator: Zinc
–Red = Nitrate Reductase (-)
–Clear = Nitrate Reductase (+)
–Gas confirms N2 gas creation
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Term
Phenylalanine Deaminase Test |
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Definition
•Differential Agent: Phenylalanine
–Identifies presence of phenylalanine deaminase
–Removes the amino group from the amino acid creating NH3 and phenylpyruvic acid
•Indicator: Ferric Chloride (FeCl3) added after incubation
–Reacts w. phenylpyruvic acid (if presents) to change color from yellow to green – a positive result |
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Term
Who are Enterobacteriaceae? |
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Definition
•Large family of G- rods (Grow on MacConkey Agar as non-fastidious)
•Called "enteric bacteria" as several members live as harmless symbionts (microbiota) in the intestines; others are opportunistic pathogens: Morganella, Citrobacter, Proteus, Enterobacter, Serratia; others are true pathogens: E. coli, Salmonella, Shigella, Yersinia, Klebsiella
•Not spore-forming
•Non Acid-fast
•Non-capsulated (except Klebsiella)
•Facultative anaerobes
•Ferment sugars to produce lactic acid and various other end products (w/wout gas)
•Nitrate reducers (most)
•Catalase positive (most)
•Cytochrome C oxidase negative (most)
•If motile, Peritrichous (non-motile Shigella and Klebsiella); some have fimbriae to adhere to the host cells; few nonmotile genera
•Some produce endotoxins |
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Term
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Definition
•Combination differential medium that is used to:
•differentiates among different groups of Enterobacteriaceae based on their ability to ferment:
−ferment glucose only
−ferment glucose AND lactose, and
−reduce sulfur
•differentiates between groups capable of reducing sulfur to hydrogen sulfide gas (H2S)
•Slanted media that is inoculated as both a fishtail streak AND a stab
–Media is divided for interpretation into “slant” and “butt”
–Reactions are read: slant / butt / gas / H2S |
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Term
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Definition
•Differential Agent(s): 0.1% (short supply) Glucose, 1% Lactose, and Sodium Thiosulfate
–Identifies sugar fermenters and/or H2S producers
•Indicator(s): Phenol Red and Ferric Ammonium Citrate
–Phenol red turns yellow in presence of acid
–Iron turns black in presence of H2S
Red slant/Red butt = no fermentation
Red slant/Yellow butt = only glucose fermentation
Yellow slant/Yellow but = both glucose and lactose fermentation
Dark Color = H2S produced |
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Term
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Definition
•Differential Agent: 5% Blood
•Indicator: hemolytic activity
–β hemolysis: complete degradation
–α hemolysis: incomplete degradation
–γ hemolysis: no degradation
–Useful in identifying the pathogenic Staphylococcus, Streptococcus, and Enterococcus sp. from less virulent
•Note: BA differs from Columbia CNA Blood Agar in that it lacks the antibiotics for selectivity |
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Term
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Definition
•Differential Agent: Fibrinogen in blood plasma
–Identifies organisms that can bind fibrinogen
–Pathogenic staphylococci can convert fibrinogen to fibrin (w. enzyme coagulase attached to bacterial wall) thus coating themselves in a protective barrier
•Indicator: Clotting (coagulation) |
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Term
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Definition
•General-purpose fermentation media
•Differential Agent: Glucose, Sucrose, or Xylose
–Fermentation of the sugars requires presence of enzymes necessary to metabolize them
•Primary Indicator: Phenol Red
–Fermentation creates acid which causes a color change to yellow
–Yellow <6.8; fermenter
-Red 6.8-7.4; non-fermenter
-Pink >7.4; non-fermenter
•Other Indicator: Durham Tube
–Used to collect gas that may be produced during fermentation
(+) yellow: acidic compounds and gas
(-) red alcaline
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Term
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Definition
pyruvate → acetaldehyde + CO2 → ethanol + NAD+
Yeast (brewing, winemaking, and baking) |
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Term
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Definition
pyruvate → lactic acid + NAD+
Human muscle cells (use this fermentation to generate ATP when O2 is scarce)
Fungi (cheese) & bacteria (yogurt) |
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Term
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Definition
•Differential Agent: Urea
–Detects the ability of the microbe to produce urease
–Produces ammonia when metabolized
•Indicator: Phenol Red
–Turns orange at a pH below 8.4
–Turns reddish-pink at a pH above 8.4 |
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Term
Lysine Decarboxylase Test |
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Definition
•Differential Agent(s): Lysine
–Lysine Decarboxylase removes the carboxyl group from peptone
–Decarboxylation results in the accumulation of alkaline products
•Indicator(s): Bromcresol Purple
–Indicator is purple at pH above 6.8 and yellow at pH below 5.2 |
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Term
Ornithine Decarboxylase Test |
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Definition
•Differential Agent(s): Ornithine
–Ornithine Decarboxylase removes the carboxyl group from peptone
–Decarboxylation results in the accumulation of alkaline products
•Indicator(s): Bromcresol Purple
–Indicator is purple at pH above 6.8 and yellow at pH below 5.2 |
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Term
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Definition
•Differential Agent: Gelatin
–Some microbes can secrete gelatinase to catabolize gelatin and absorb the amino acids
•Indicator: liquification of gelatin |
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Term
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Definition
•A series of biochemical tests designed to differentiate enteric organisms (e.g, E. coli from Enterobacter sp.)
•Stands for these tests:
Indole ←SIM Test
Methyl Red
Voges-Proskauer
Citrate |
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Term
SIM = Sulfide-Indole-Motility Test |
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Definition
•Semisolid medium (agar concentration reduced from the typical 1.5% to 0.4%)
•Determines 3 bacterial activities:
–Sulfur redaction into H2S (hydrogen sulfide)
–Indole production (from tryptophan hydrolysis)
–Motility |
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Term
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Definition
•S stands for sulfide
•Differential Agent: Sodium Thiosulfate
–Identifies organisms that can produce hydrogen sulfide (H2S)
•S Indicator: Iron
-H2S forms a black precipitate |
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Term
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Definition
•I stands for indole
•Differential Agent: Tryptophan
–Identifies organisms that can produce tryptophanse
•I Indicator: Kovac’s Reagent (dimethylaminobenzaldehyde and HCl)
–Tryptophan is catabolized to indole
–Added after incubation and forms a red fluid in the presence of indole |
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Term
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Definition
•M stands for motility
•Differential Agent: 0.4% Agar
–Identifies organisms that are motile via flagella
•M Indicator: Turbidity
–Motility will result in a “cloudiness” that often obscures the original stab line |
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Term
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Definition
•Determines whether end product of glucose fermentation are mixed acids
–Mixed acid production lowers the pH of the media below 4.4
•Differential Agent: Glucose
•Indicator: Methyl Red Dye
–Methyl Red is red at pH 4.4 or less
–Orange at pH 4.4-6.2
–Yellow at pH 6.2 |
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Term
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Definition
•Determines whether end product of glucose fermentation is alcohol
–The alcohol (2,3-butanediol) itself is undetectable
–The intermediate (Acetoin) is detectable
•Differential Agent: Glucose
•Indicator: VP Reagent A (α-Naphthol) and VP Reagent B (KOH)
–VP reagents oxidize acetoin to diacetyl which has a red color |
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Term
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Definition
•Differential Agent: Citrate
–Only microbes that make citrate-permease can convert citrate to pyruvate
–Only those microbes survive
•Indicator: Bromthymol Blue
–Microbes that survive will also convert ammonium phosphate to ammonia
–Ammonia increases the pH of the media
–Indicator turns blue at pH 7.6 |
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Term
Antimicrobial Susceptibility Test |
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Definition
•Measure the diameter of the zone of clearing for each antibiotic disc used
•Determine the degree of resistance or susceptibility for each organism and the 4 antibiotics tested by using the info in the Table 7-3 (pg. 449)
Differential Agent: Antibiotics
Penicillin (cell wall)
Ciprofloxacin (DNA replication)
Trimethoprim (synthesis of AGCT&U)
Chloramphenicol (protein synthesis)
Indicator: Zone of Clearing
Clearing (diameter recorded in mm) indicates whether an organism is Resistant (“R”) or Susceptible (“S”) to antibiotic
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