75 Questions
What is the primary purpose of using serological markers in suspected parasitosis cases?
To confirm the presence of parasitic infections
What type of genetic material sequences are minisatellite and microsatellite sequences?
Highly variable areas
Which specific antibody is detected in body fluids as a marker for early tick-borne infections?
IgM
Which sequences are used for species differentiation according to the text?
Mitochondrial genes
Which antigen is associated with Echinococcus granulosus infection?
Em 1 antigen
In which situations are molecular methods indicated according to the text?
Differentiation of similar species
What is the main characteristic of the fungal components detected in body fluids?
Released during fungal growth
What is the purpose of using molecular methods in cases of low intensity infections?
To confirm infection
Which infection is associated with detection of Candida glucuronoxylomannan?
Cryptococcus
Which method does not require DNA multiplication according to the given text?
Fluorescent in situ hybridization (FISH)
Which class of antibodies is detected in body fluids for elder tick-borne infections?
IgG
What is the initial step in methods based on PCR reactions according to the text?
Multiplication of DNA
Which infection is associated with detection of Trichinella-specific antibodies?
Trichinella
Which sequences are used at higher taxonomic levels according to the text?
DNA of a small subunit of ribosomal RNA
Which sequences are used for differentiation of strains or individuals according to the author?
Internal transcribed spacer (ITS)
Which method allows for the isolation of a specific protein from within a mixture of proteins?
Immunoprecipitation
Which antibody type is responsible for early stages of immunity?
IgM
Which antibody type is found in saliva, tears, and breast milk?
IgA
What type of immunoassay is known for its chemiluminescent detection?
Chemiluminescence immunoassay (CLIA)
Which antibody type activates basophils and mast cells?
IgD
When should serological methods be used in diagnosis?
In cases of suspected chronic and systemic fungal infection
What is the purpose of Multiplex PCR in diagnostics?
To diagnose several pathogens simultaneously
Which method allows real-time observation of PCR amplification?
Amplification with fluorescent probes
What is a common disadvantage of molecular methods like PCR?
Frequent false negative results
What is an advantage of using real-time PCR in diagnostics?
Speed of obtaining the result
Why is small amount of material needed for PCR considered an advantage?
It makes testing more cost-effective
What is a downside of the high sensitivity in molecular methods?
Increased likelihood of false negative results
What does the lack of standardization in DNA isolation methods lead to?
High costs
What can be a drawback of too high sensitivity testing in molecular methods?
Easy contamination of samples
What is the purpose of denaturation in a polymerase chain reaction?
To melt the double helix and break hydrogen bonds
What occurs during the annealing step of a polymerase chain reaction?
Lowering the temperature to hybridize primer sequences
What determines the temperature used in the annealing step of a PCR reaction?
Length of the primers and content of GC pairs
Which statement best describes the extension/elongation step in a PCR reaction?
Synthesis of a complementary strand by a polymerase
How is the control of the amplification process in PCR achieved?
By selecting appropriate temperatures and repetition cycles
What is used as a template in subsequent cycles of a polymerase chain reaction?
The product of one reaction cycle
Which factor determines the exponential amplification of products in PCR?
Number of repetition cycles
What is needed for a polymerase to synthesize a complementary strand in a PCR reaction?
Primer sequences
What step of the PCR reaction involves the binding of primers to the target DNA sequence?
Extension
Which of the following is a common disadvantage associated with molecular methods like PCR?
High cost
How is the temperature used in the annealing step of a PCR reaction determined?
By the length and sequence of the primers
How is the control of the amplification process achieved in PCR?
By monitoring fluorescence intensity
Which of the following is NOT an advantage of using PCR as a molecular method?
Low likelihood of contamination
What is a key disadvantage of PCR related to selectivity?
The need for appropriate primers
Which factor determines the rate of gene amplification during a PCR reaction?
Amplification time
In PCR, what is the purpose of the extension/elongation step?
Adding complementary nucleotides to the template strand
How is the control of the amplification process achieved in PCR?
By maintaining the appropriate temperature
Why is the high sensitivity of PCR considered an advantage?
To detect small amounts of genetic material
What is the main purpose of the extension/elongation step in a PCR reaction?
To amplify the DNA segments using DNA polymerase
Why is temperature control important in the amplification process of PCR?
To prevent the reaction from proceeding too fast or too slow
What is a potential advantage of PCR in terms of amplification process control?
High sensitivity and specificity of amplification reactions
In terms of advantages and disadvantages, which statement best reflects a common drawback of PCR?
Potential contamination issues during amplification
What is the purpose of the extension/elongation step in a PCR reaction?
Amplify the DNA fragment
In a polymerase chain reaction, what determines the temperature used during the annealing step?
AT and GC content of primers
How is the control of the amplification process achieved in a PCR reaction?
By monitoring the number of cycles
What is an advantage of using real-time PCR in diagnostics?
Continual monitoring of the amplification progress
What is a common disadvantage of small amount of material needed for PCR?
Increased risk of contamination
What is the main purpose of the extension/elongation step in a PCR reaction?
Amplifying the DNA sequences
Why is temperature control important during the annealing step of a PCR reaction?
To ensure primers bind to the target DNA
How is the amplification process controlled in PCR?
By regulating the temperature cycles
What is an advantage of using a small amount of material in a PCR reaction?
Reduced turnaround time
What is a common disadvantage of too high sensitivity testing in molecular methods like PCR?
Increased false positive results
What is the purpose of the extension/elongation step in a PCR reaction?
To amplify the DNA by polymerase synthesis
What is the main purpose of the annealing step in a polymerase chain reaction?
Attaching primer sequences to the DNA strand
What primarily determines the temperature used in the annealing step of a PCR reaction?
The presence of GC pairs in the DNA
How is the control of the amplification process achieved in PCR?
By repeating cycles without adding components
What is a key advantage of PCR as mentioned in the text?
Exponential amplification of products
What is the main function of DNA polymerase in a PCR reaction?
Synthesizing a complementary strand based on a single-stranded DNA chain
Why is deionized water an essential component of a PCR reaction?
To prevent DNA digestion by enzymes
What is the role of primers in a PCR reaction?
Facilitating the start of DNA synthesis by DNA polymerase
What is the purpose of using dyes like ethidium bromide in PCR product visualization?
To facilitate the separation of DNA products in gels
Why is having a free 3' end important for primers used in PCR?
To facilitate the start of DNA synthesis by DNA polymerase
Which component of PCR reacts with the substrates dATP, dCTP, dGTP, and dTTP to construct new DNA strands?
DNA polymerase
What is the function of Mg2+ in a PCR reaction?
Acting as a cofactor for DNA polymerase
In PCR, why is it essential for primers to be complementary to the DNA strand surrounding the amplification site?
To ensure accurate initiation of DNA synthesis by DNA polymerase
'Amplification site' mentioned in the text refers to:
The location where primers bind to the target DNA sequence
Study Notes
Molecular Diagnostics
PCR (Polymerase Chain Reaction)
- A method of observing the amplification in real-time using fluorescent probes or markers
- Enables the diagnosis of several pathogens at the same time
- Applications:
- Detection of Candida, Aspergillus, Cryptococcus
- Differentiation of Taenia solium, T. saginata, Trichinella sp.
Real-time PCR
- A method of observing the amplification in real-time using fluorescent probes or markers
- Applications:
- Detection of Candida (LightCycler), Aspergillus fumigatus
- Diagnostics of Toxoplasma gondii, Giardia (from the environment), Plasmodium, Cryptosporidium, Trypanosoma
- Differentiation of Neospora, Trichinella, Dirofilaria
Multiplex PCR
- A method of simultaneously amplifying multiple sequences in one reaction
- Applications:
- Detection of Candida, Cryptococcus, Aspergillus, Penicillium
- Detection of Giardia
Nested PCR
- A method of increasing sensitivity and specificity by using two sets of primers
- Applications:
- Diagnostics of Pneumocystis
- Detection of Candida, Cryptococcus, Aspergillus, Penicillium
- Detection of Giardia
Molecular Methods
- Advantages:
- Possibility of using different materials
- Small amount of material needed for testing
- Speed of obtaining the result
- High sensitivity
- Disadvantages:
- Frequent false negative results
- Too high sensitivity
- Lack of standardization of DNA isolation methods
- Easy contamination of samples
- High cost
Serological Methods
- Advantages:
- Antigen detection at an early stage of infection
- Fast detection
- High sensitivity
- High specificity
- Disadvantages:
- False positive or false negative results
- Elimination of antibodies from the bloodstream
- Cross reactions
- Antigenic similarity between microorganisms
- Lack of antibodies in immunocompromised people
Explore the use of molecular diagnostics in genetics by searching for specific sequences in the genetic material, including highly variable areas like minisatellite and microsatellite sequences, moderately variable sequences like internal transcribed spacer (ITS) and mitochondrial genes, and conservative sequences like DNA of ribosomal RNA. Learn about their applications in differentiation at various taxonomic levels.
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