Superbugs MCQ

Acinetobacter baumannii is a _____ bacteria.

Gram-negative

We determined the MIC values of our mutant strains to which three antibiotics?

Vancomycin, colistin, polymyxin B

The E-test relies upon:

Diffusion of antibiotics from plastic strips into solid media plates

The E-test is used to determine:

The minimum inhibitory concentration of an antibiotic

The minimum inhibitory concentration (MIC) of an antibiotic is:

The lowest concentration of an antibiotic that inhibits bacterial growth

During the first step of RNAseq the RNA is copied using which enzyme?

Reverse transcriptase

RNAseq is the set of experimental procedures that generates ____ molecules derived from RNA molecules.

cDNA

What is RNAseq?

A method for transcriptome profiling

In the Sanger DNA sequencing method dideoxynucleotides:

lack a 3’ hydroxyl group

How many sequencing reactions are necessary in order to determine a DNA sequence using Sanger sequencing?

4

The Sanger sequencing method uses the following to terminate newly synthesized DNA fragments:

Dideoxynucleotides

When measuring DNA concentration the ratio of the absorbance values obtained at 260 nm and 280 nm (A260/A280) is used to:

determine the purity of the DNA

The lpxC gene is involved in which bacterial process?

Lipopolysaccharide biosynthesis

Which of the following components of the PCR reaction in Week 4 made it specific for amplification of the lpxC gene?

Primers

During DNA electrophoresis:

Shorter DNA fragments migrate faster than larger fragments

Taq polymerase participates in which step of PCR?

DNA synthesis

Acinetobacter baumannii produces which types of infections?

Ventilator-associated pneumonia, urinary tract infections, bloodstream infections

What is true regarding the resistance to the antibiotic colistin in Acinetobacter baumannii?

Resistance to colistin has been observed in multiple geographic locations

Lipopolysaccharide (LPS) is found in which type of bacteria?

Gram-negative bacteria

The function of LPS is to:

Provide structural rigidity to bacterial outer membrane

Lipopolysaccharide consists of the following three subunits:

Lipid A, core polysaccharide, O polysaccharide

Colistin is active against which type of bacteria?

Gram-negative bacteria

List mechanisms by which bacteria can become resistant to antibiotics:

Antibiotic inactivation or modification

bypassing metabolic inhibition

preventing antibiotic accumulation within the bacteria cell

alteration of antibiotic targets or binding sites

In the Week 1 laboratory session we used growth media plates containing collision in order to:

select for mutations that occurred randomly during bacterial growth before being exposed to colistin

Prevent the growth of bacteria that were susceptible to colistin

Name three components needed for PCR:

DNA polymerase, nucleotides, primers

Colistin kills bacteria by:

disrupting the bacterial membrane

The abbreviation "MDR" when referring to Acinetobacter baumannnii strains signifies?

multidrug resistance

Currently, the antibiotic _________ seems to be the most reliably effective drug in vitro against MDR Acinetobacter baumannii.

colistin

Based on what you learned last week in lab, the mechanism explaining how Acinetobacter baumannii becomes resistant to colistin is:

Alteration of antibiotic targets or binding sites.

1. B-lactamases confer resistance to penicillins by:

Antibiotic inactivation or modification.

In last week’s laboratory session we plated dilutions of the Acinetobacter baumannii culture on growth media plates with no antibiotic in order to:

 

Determine the amount of bacteria present in the culture

The three steps of a PCR reaction are:

Denaturation, Annealing, DNA synthesis

The gene from your colistin resistant mutants of Acinetobacter baumannii that you will be amplifying using PCR in today's laboratory session is:

lpxC

In the Week 1 laboratory session, we plated dilutions of the Acinetobacter baumannii culture on plates with no antibiotic in order to:

Determine the amount of A. baumannii in the culture

Durang agarose gel electrophoresis, DNA migrates:

toward the positive electrode

The running buffer used during DNA electrophoresis:

Helps to conduct electricity through the gel

During agarose gel electrophoresis, DNA migrates:

Based on its size

During DNA electrophorsis, ethidium bromide is used to:

Visualize the DNA

In this week’s lab session (Week 5), the agarose in the gel slice containing the PCR products from last week’s lab is dissolved using:

 

Heat and a specific buffer

The nanodrop device is used to:

measure DNA concentration

Which of the following is used as a template during Sanger DNA sequencing:

 

An existing DNA strand

In the Sanger sequencing method, DNA fragments are separatd by:

size

RNA seq can be used for:

Studying changes in gene expression

One of the biggest problems with RNA isolation is:

RNA degradation

Based on what you know about your mutant strain, how will its minimum inhibitory concentration (MIC) value to colistin compare to the MIC value to colistin of the parental strain from which it was derived?

 

The MIC value will be higher

Bacteria are classified as Gram positive or Gram negative based on:

Differences in the bacterial cell wall that result in differences in their ability to retain stains

Both Gram negative and Gram positive bacterial have peptidoglycan?

True

Vancomycin targets which type of bacteria:

Gram positive bacteria

The mechanism of action of vancomycin is:

Prevents cross-linking of components of the peptidoglycan

Polymyxin B is from the same class of antibiotics as:

Colistin

We are performing RNAseq with its associated analysis in order to:

Identify genes that are differentially expressed in colistin resistant mutants

What is the purpose of Pathway Enrichment Analysis?

It summarizes RNAseq data into a list of biological pathways containing genes for which expression levels have been affected in an experiment.

What are GO terms and what is their role in RNAseq analysis?

Terms that identify the biological processes in which a gene participates

True or False: If a pathway is enriched in a pairwise comparison of the colistin susceptible stain and its colistin resistant mutant, it means that pathway had increased expression in the colistin resistant mutant.

False