Exam 8: Nucleic Acid-Based Analytic Methods for Microbial Identification and Characterization

Which type of hybridization method would be the optimal choice to use to detect a lesion infected with a particular virus?

While developing a new hybridization-based molecular test for Cryptosporidium,a protozoan parasite that causes diarrheal illness,a laboratory technician examines the hybridization ability with a closely related,but nontarget,protozoan and also gets a positive test result.In order to improve the stringency of the hybridization reaction for detection of Cryptosporidium only,the technician can do which of the following?

After PCR,the amplification control has failed to yield a product.What should you do?

Gel electrophoresis is used to separate nucleic acid amplicons based upon what physical property?

Hybridization methods are based on:

If a patient sample contains 8 copies of viral DNA,predict how many DNA copies would be present following three rounds of PCR amplification.

Which of the following molecular techniques,or combination of techniques,would be most appropriate for detection and quantitation of an RNA retrovirus,like HIV,in a blood sample in order to establish the patient's viral load?

Predict which of the following DNA oligonucleotide probes would have the highest melting temperature (Tm)when hybridizing to the target sequence 5'-GTGCCTGAATGCAATGTCA-3'.

Isothermal amplification techniques,such as NASBA,utilize a single temperature for nucleic acid amplification thereby eliminating the need for thermal cycling instruments to precisely and quickly alter the reaction temperature.This often reduces the cost associated with molecular testing and infrastructure requirements.In what settings could this be advantageous?

Target nucleic acid amplification (polymerase chain reaction [PCR])methods are based on:

Gen-Probe Mycobacterium tuberculosis direct test uses which type of nucleic acid amplification test?

Which enzyme recognizes a specific nucleotide sequence (~4 to 8 nucleotides in length)and catalyzes the digestion of the nucleic acid at that site,causing a break in the DNA strand?

What key advantage do emerging technologies,such as MALDI-TOF and next generation sequencing,have over conventional hybridization and amplification techniques?

Place the basic steps involved in a molecular hybridization assay in sequence from first to last in the order in which they would be performed.

Which of the following steps are crucial for the success of a nucleic acid amplification test,such as PCR?

Determining the exact nucleotide sequence of a gene or gene fragment obtained from an unknown organism is based on which of the following methods?

The enzyme that is commonly used for primer extensions in the PCR method works best at what temperature?

What differentiates diagnostic techniques that employ phenotypic (culture-based)methods from those that employ molecular methods?

Analytical sensitivity is concerned primarily with which of the following PCR parameters?

The target in the hybridization assay can be described as: