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Questions and Answers
Which phenomenon is likely to cause the most significant changes in the immune response?
Which phenomenon is likely to cause the most significant changes in the immune response?
What was the estimated global death toll during the 1918 pandemic?
What was the estimated global death toll during the 1918 pandemic?
What is the primary reason for needing a seasonal flu shot?
What is the primary reason for needing a seasonal flu shot?
During which pandemic did H1N1 cause widespread illness due to reassortment events?
During which pandemic did H1N1 cause widespread illness due to reassortment events?
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How many deaths did the 1968 pandemic approximately lead to worldwide?
How many deaths did the 1968 pandemic approximately lead to worldwide?
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What does HPAI stand for in the context of bird flu?
What does HPAI stand for in the context of bird flu?
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When was the first HPAI A(H5N1) bird flu outbreak reported in dairy cows?
When was the first HPAI A(H5N1) bird flu outbreak reported in dairy cows?
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What significant development regarding H5N1 bird flu was reported in Oregon?
What significant development regarding H5N1 bird flu was reported in Oregon?
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What is the primary reason swine are considered efficient influenza mixing bowls?
What is the primary reason swine are considered efficient influenza mixing bowls?
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What is a significant consequence of the rapid evolution of HIV?
What is a significant consequence of the rapid evolution of HIV?
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How many groups of HIV have arisen from simian immunodeficiency viruses (SIV) jumping to humans?
How many groups of HIV have arisen from simian immunodeficiency viruses (SIV) jumping to humans?
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Why has the development of an effective vaccine for HIV been challenging?
Why has the development of an effective vaccine for HIV been challenging?
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Which of the following statements about SARS-CoV-2 is accurate?
Which of the following statements about SARS-CoV-2 is accurate?
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What is the host range specificity of HIV?
What is the host range specificity of HIV?
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What contributes to the evolution of viruses like HIV in a host?
What contributes to the evolution of viruses like HIV in a host?
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What characterizes the viral structure of coronaviruses, including SARS-CoV-2?
What characterizes the viral structure of coronaviruses, including SARS-CoV-2?
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What is one method by which antibiotic resistance can arise in bacteria?
What is one method by which antibiotic resistance can arise in bacteria?
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Which of the following is true about Methicillin Resistant Staphylococcus aureus (MRSA)?
Which of the following is true about Methicillin Resistant Staphylococcus aureus (MRSA)?
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What is a major contributor to the development of antibiotic resistance in agricultural settings?
What is a major contributor to the development of antibiotic resistance in agricultural settings?
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How do bacteria acquire new resistance genes through horizontal gene transfer?
How do bacteria acquire new resistance genes through horizontal gene transfer?
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What best describes antigenic drift in the context of viral evolution?
What best describes antigenic drift in the context of viral evolution?
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What role does the SCCmec gene cassette play in MRSA?
What role does the SCCmec gene cassette play in MRSA?
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What is the primary difference between antigenic drift and reassortment in viral evolution?
What is the primary difference between antigenic drift and reassortment in viral evolution?
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What is the main consequence of the high frequency of antibiotic use in the U.S.?
What is the main consequence of the high frequency of antibiotic use in the U.S.?
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Study Notes
Microbial Evolution - Applied Aspects
- Microbial evolution influences antibiotic resistance and viral evolution.
- Antibiotics are used extensively in the US, with a significant portion used in agricultural animal production.
- Approximately 70% of hospital-acquired infections are caused by resistant bacteria.
- Changes in gene frequency in bacteria are due to selection and genetic drift.
- Antibiotic resistance development includes spontaneous mutation modifying genes, altering antibiotic targets, and changing cell permeability. Horizontal gene transfer acquires resistance genes for enzymes inactivating antibiotics and compensating for losses in protein function.
Evolution in Action
- E. coli, grown in minimal glucose medium, demonstrate adaptive evolution.
- Initial mutants had low citrate use, but fitness increased over multiple generations, showing how evolution can improve fitness.
- Rhodobacter capsulatus can use malate for growth either through anoxygenic photosynthesis or fermentation.
- Mutants selected in the dark show changes in bacteriochlorophyll that are lost in light.
Evolution of Antibiotic Resistance
- The graphic shows antibiotic usage and resistance increasing over time.
- A notable increase in the usage of antibiotics occurred within a given period.
- Significant amounts of antibiotics are used, contributing to the development of antibiotic resistance.
- The evolution of antibiotic resistance is a growing concern due to the frequency of acquired resistance in bacteria.
Viral Evolution - Influenza A
- Influenza A viruses are categorized by H (hemagglutinin) and N (neuraminidase).
- Variants arise due to immune reactions, with varying types of H and N in human populations.
- Antigenic drift results from mutations, typically 2-3 amino acid replacements, leading to seasonal flu variations. Reassortment leads to a complete shift, potentially causing a pandemic.
- Pandemic fluctuations occurred in 1918, 1957, and 1968. Seasonal flu outbreaks are common and significant.
Viral Evolution - HIV
- HIV is a ssRNA (+) virus affecting primates.
- HIV-1 is a chimpanzee-derived origin, and HIV-2 is a monkey origin.
- The virus exhibits high mutation rates and variation, making vaccine development challenging, causing immune system evasion and promoting drug resistance.
- HIV has jumped to humans at least twice, leading to multiple groups and variations.
Genomic Analysis of SARS-CoV-2
- No evidence for reassortment of SARS-CoV-2 with other viruses.
- SARS-CoV-2 has a proofreading enzyme, hence the slower rate of mutations relative to flu.
- The large majority of strains are remarkably similar, with less than 53 substitutions per genome.
- Spike Protein mutations can affect receptor affinity and infectivity.
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Description
Explore the critical aspects of microbial evolution, including its role in antibiotic resistance and viral changes. Understand how selection, genetic drift, and horizontal gene transfer contribute to the development of resistant bacteria and adaptive evolution in various microbes. This quiz will test your knowledge of these essential biological principles.
