Molecular methods Flashcards

1
Q

Study of proteins on the cellular level which could provide information about disease process, environmental conditions, drug effectivity, etc.

A

Proteomics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Study of DNA of an organism to characterize it further in molecular level.

A

Genomics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Study of microbial genes from the environment and human normal flora that may affect human health, metabolism, nutrition, and immune function. The study is intended for non-culturable microorganisms, since only 1% of all prokaryotes on Earth are culturable in the laboratory.

A

Metagenomics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

A DNA sequence that encodes a specific product.

A

Gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Comprises all genes in an organism.

A

Genome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

A single, unpaired (haploid) circular dsDNA molecule that contains bacterial genetic information.

A

Bacterial Chromosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

dsDNA, closed, circular autonomous extrachromosomal genetic element.

A

Plasmid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Extrachromosomal mobile genetic elements.

A

Mobilome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

A form of cell division; mode of bacterial replication.

A

Binary fission

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

DNA polymerase enzyme; STEPS: Unwinding/Relaxation of DNA → Separation → Synthesis → Termination.

A

DNA Synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

UAA, UAG, UGA.

A

STOP codons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Transcription and Translation.

A

Gene expression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Site of active replication.

A

Replication fork

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Initiation site of nucleic acid synthesis.

A

Promoter sequence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Triplets of nucleotide bases; Each codon codes for a specific single amino acid.

A

Codons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Anabolic process (Biosynthesis) vs Catabolic process (Biodegradation).

A

Metabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Amplified PCR product (Contamination in PCR lab).

A

Amplicon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Areas that are free from amplified products of PCR.

A

Clean room

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Areas in which amplification is done (PCR room); may have contaminating amplicons.

A

Dirty room

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Inactivates DNA in the sample leading to false negative PCR assay.

A

Dnase enzyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Found ubiquitously in the environment and human body; can cause false negative PCR assay but can be inactivated by using RNAse-free materials or treatment with guanidinium isothiocyanate.

A

RNAse enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Reduces background amplification in hybridization methods that could interfere in the analysis of relevant amplification signals.

A

Isocytidine (isoC) and isoguanosine (isoG)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Reduces carryover/contamination from PCR assays.

A

Uracil-N-Glycosylase (UNG)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Are number of cycles a significant rise of fluorescence (10x the SD) above background is detected. Also known as CT (Cycle threshold) or CP (Crossing point) or CQ (Cycle of Quantification).

A

CT value

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

The temperature in which DNA denatures/melts into two single strands.

A

Melting temperature (Tm)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

These are a set of conditions that measure the likelihood of a double-stranded nucleic acid to dissociate into its constituent single strands.

A

Stringency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Single-stranded nucleic acid sequence that is used to identify a specific sequence of DNA/RNA from the sample with reporter molecule for detection of signals.

A

Probe

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Single-stranded nucleic acid sequence that functions like a probe but without a reporter molecule. The primers can be specific for the genes that code for the microorganism’s genus, species, virulence factors, or antibiotic resistance.

A

Primer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Detection of a single nucleic acid target for detection and identification of a microorganism in a molecular assay.

A

Monoplex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Detection of multiple nucleic acid targets using cocktails of probes to detect multiple numbers of pathogens simultaneously in a single reaction. Disadvantage: Competition for resources among multiple amplifying sequences and cross-reaction between primers.

A

Multiplex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Fluorescence Resonance Energy Transfer, the transfer of energy from a donor dye molecule to an acceptor dye molecule.

A

FRET

32
Q

Indications for molecular assays include hard-to-grow fastidious microorganisms, extensive delays in cultivation, lack of reliable methods for identification, and characterization of previously unknown organisms or strains of known organisms during epidemics, mutated organisms, or antibiotic resistance mechanisms. Organisms do not need to be alive.

A

Indications of Molecular Assays

33
Q

Limitations of molecular assays include less sensitivity for multiplex assays, troublesome contamination, false positives, complex and technical methods, discriminatory properties, cost, and lack of standardization.

A

Limitations of Molecular Assays

34
Q

Use plastic swabs rather than wooden or wired shafts. Do not use calcium alginate swabs with aluminum shafts as it interferes with amplification of nucleic acids. All materials including pipettes, surfaces, tubes, microcentrifuge tubes should be DNase/RNase-free to avoid degradation of sample nucleic acids leading to false-negative results.

A

Pre-analytical factors

35
Q

Method for nucleic acid-based tests that involves the production and labeling of nucleic acid probes, preparation of target nucleic acid from the specimen, hybridization, and detection of hybridization.

A

Hybridization

36
Q

Electrophoresis followed by staining with Ethidium bromide.

A

Southern Hybridization

37
Q

A hybridization method that involves the detection of pathogen in the patient’s cell or tissues.

A

Fluorescence in situ Hybridization

38
Q

Use of increased salt to lower stringency, which can result in double-stranded DNA becoming single-stranded, and increased temperature to increase stringency, often with the use of urea and formamide.

A

Stringency (Extraction)

39
Q

Amplification steps

A

STEPS: 1. Extraction of Target nucleic acid from specimen 2. Amplification 3. Detection of amplified products.

40
Q

DNA amplification or DNA xeroxy, invented by Kary Mullis, is the most common nucleic acid amplification method used in molecular diagnostics

A

POLYMERASE CHAIN REACTION (PCR)

41
Q

Conventional PCR has —- repetitive thermal cycles: temperature-dependent

A

20-50

42
Q

Extract nucleic acid with heat/chemical/enzyme.

A

Denaturation (94°C)

43
Q

Primer (specific to target DNA sequence) is added to the denatured DNA.

A

Annealing (50-58°C)

44
Q

Taq Polymerase is used. Can amplify a single copy into 10^7 to 10^8 copies.

A

Elongation (72°C)

45
Q

A DNA or RNA segment extracted from the sample which serves as the target for PCR.

A

Template

46
Q

Oligonucleotide that is specific for the target sequence present in the template.

A

Primers

47
Q

Synthesizes new strands of DNA and must be thermostable for PCR.

A

DNA Polymerase

48
Q

Also known as RNA-dependent DNA Polymerase, used ONLY in RT-PCR to synthesize complementary DNA (cDNA) from an RNA template.

A

Reverse Transcriptase

49
Q

Cofactor of DNA Polymerase.

A

Magnesium Chloride (MgCl2)

50
Q

Ensures proper pH for DNA Polymerase to function.

A

Buffer

51
Q

Used by DNA polymerase to synthesize new DNA strands during the Elongation phase.

A

Deoxynucleotides (dNTPs)

52
Q

Instrument used in PCR that adjusts temperature depending on the step being conducted.

A

Thermal Cycler

53
Q

A heat-stable DNA polymerase used in PCR; taq polymerase.

A

Thermus aquaticus

54
Q

A heat-stable DNA polymerase used in PCR, known for its proofreading ability; Pfu polymerase.

A

Pyrococcus furiosus

55
Q

Heat-stable DNA polymerase used in PCR, with high fidelity (Wind or TLi polymerase or Vent polymerase)

A

Thermococcus litoralis

56
Q

A heat-stable DNA polymerase used in PCR, capable of amplifying both DNA and RNA templates; Tth polymerase

A

Thermus thermophilus

57
Q

Amplification followed by gel electrophoresis and band staining to detect amplified products.

A

Conventional PCR

58
Q

PCR process where amplicon accumulation is detected in real-time by fluorophores that send fluorescent signals.

A

Real-time PCR (Quantitative PCR or qPCR)

59
Q

Stages of Real-time PCR

A

Lag, Exponential, and Plateau phase

60
Q

Real-time detection methods

A

5’Nuclease (TaqMan) PCR, SYBR Green, Dual-probe FRET, molecular beacon, Scorpion primers.

61
Q

Real-time PCR commercial platforms

A

Roche LightCycler, Bio-Rad CFX96, 3M Integrated Cycler, GeneXpert (Cepheid), GeneAMP 5700, and Prism 7700.

62
Q

Performed with two successive PCR reactions: 1st PCR amplifies a large fragment, 2nd PCR amplifies smaller fragments of the 1st PCR amplicons.

A

Nested PCR

63
Q

Separates individual nucleic acids into ≥20,000 droplets using a microfluidic technique to analyze if each droplet has the target molecule.

A

Digital PCR

64
Q

Uses RNA as the template; RNA is first converted into cDNA, then usual PCR steps proceed.

A

Reverse Transcription PCR (RT-PCR)

65
Q

Real-time detection of amplicons made by amplifying RNA target sequences, especially for viruses (SARS-CoV-2, HIV, Hepatitis C, Ebola, Zika).

A

Real Time RT-PCR

66
Q

Detection of multiple nucleic acid targets for one or more microorganisms in a single reaction.

A

Multiplex PCR

67
Q

Inversely proportional to the nucleic acid concentration present in the sample.

A

CT value

68
Q

Determines the exact nucleotide sequence of a single gene from an organism for identification and mutation analysis.

A

Nucleic acid sequencing

69
Q

During amplification, pyrophosphate (PPi) is released and converted to ATP, generating light detected as a pyrogram.

A

Pyrosequencing

70
Q

Identifying drug-resistant infections, bacteria, fungi, and viruses.

A

Pyrosequencing Uses

71
Q

Receiving/Reception, Extraction, Reagent Prep, Template Addition, PCR, Data Management (Clean rooms; Dirty room with amplicons).

A

Sections of Molecular Laboratory

72
Q

DNA molecules attached to a solid support, used to detect gene expression, mutations, and pathogen identification.

A

DNA Microarrays and Nanoarrays

73
Q

Can detect gene expression and mutations or identify new genes, holding DNA of thousands of pathogens simultaneously.

A

DNA Microarrays

74
Q

More sensitive than microarrays, capable of screening more molecules without coupled reporters.

A

Nanoarrays

75
Q

Rapid identification and antimicrobial susceptibility testing; Identification within 2 hours using cartridge and FISH probes for bacteria and fungi; MIC determination within 7 hours using morphokinetic cellular analysis via dark-field microscopy; Same day AST results; FDA approved for blood culture, others in progress.

A

Accelerate Pheno System

76
Q

By Giles Scientific USA; Utilizes digital imaging to automate zone of inhibitions reading, colony counting, and examination of chromogenic agar.

A

TRINITY V3

77
Q

By Giles Scientific USA; Utilizes digital imaging to automate CLSI/EUCAST interpretations for broth microdilution, agar dilution, disk diffusion, MIC strip/E-test, organism identification through API, RapID, or Liofilchem, colony count, and urine screening.

A

BIOMIC V3