Introduction to Virology

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Questions and Answers

What is the method used for interactive polling during the lecture?

Slido (correct)

Google Forms

Zoom polling feature

Webex only

Who is currently teaching the course MIMM 211?

Dr. Maria Smith

Dr. John Doe

Dr. Jacques Archambault

Dr. Jasmin Chahal (correct)

What is the primary subject of Dr. Jacques Archambault's research?

Immunology

Virology

Human Papillomaviruses (correct)

Bacterial Pathogenesis

What should students do before emailing Dr. Chahal regarding content or assessments?

Explain previous steps taken to find answers Signup and view all the answers

When will the lecture slides for the module be posted?

The day before the lecture Signup and view all the answers

What does the outermost layer of a virus provide for host cells?

Protection and recognition sites Signup and view all the answers

What state does a virus enter after its capsid is removed?

Intracellular state Signup and view all the answers

Which bacteriologist first filtered diseased plant sap to discover viruses?

Dimitri Iwanowski Signup and view all the answers

Which hypothesis suggests that viruses evolved after host cells appeared?

Cell-first hypothesis Signup and view all the answers

What key concept was pioneered by Sarah Stewart regarding viruses?

Some viruses can lead to cancer Signup and view all the answers

What does the term viruses mean in Latin?

Poison or slimy liquid Signup and view all the answers

What was a significant outcome of Wendell Stanley's research in 1946?

Isolation and characterization of Tobacco Mosaic Virus Signup and view all the answers

What remains uncertain regarding the origin of viruses?

Whether they evolved before or from cells Signup and view all the answers

What common characteristic distinguishes viruses from bacteria?

Viruses can pass through 0.2 micron filters Signup and view all the answers

What is the primary reason viruses must infect a host cell?

To acquire energy and metabolic intermediates Signup and view all the answers

What does the term 'virion' refer to?

The virus particle in its extracellular form Signup and view all the answers

Which of the following best describes the nucleocapsid of a virus?

The nucleic acid surrounded by a protein coat Signup and view all the answers

Which characteristic is NOT true for viruses?

They can reproduce independently outside of a host Signup and view all the answers

What is the function of glycoproteins on the surface of some viruses?

To assist in the recognition and attachment to host cells Signup and view all the answers

Which statement about a virus's extracellular state is true?

It can exist in a form called a virion Signup and view all the answers

What is necessary for viral replication to occur?

Entry into a suitable host cell Signup and view all the answers

What structure surrounds the viral nucleic acid in some viruses, providing an additional layer?

Envelope Signup and view all the answers

In what way do viruses differ from living microorganisms?

Viruses cannot reproduce without a host cell Signup and view all the answers

What role do viruses play in the evolution of organisms?

They influence diversity and evolution among species. Signup and view all the answers

Which statement best describes the quantity of viruses on Earth?

Scientists estimate there are about 10 quintillion virus particles present. Signup and view all the answers

What is a potential benefit of studying viruses?

They can provide insights into molecular biology principles. Signup and view all the answers

In what way can viruses be utilized in modern medicine?

Viruses can be engineered for gene therapy and cancer treatment. Signup and view all the answers

How do some viral genomes impact human genetic material?

They can become part of our genetic material over time. Signup and view all the answers

What is one of the main challenges associated with studying viruses?

Their infectious nature often complicates research. Signup and view all the answers

Which consequence of viruses is not typically recognized?

They exclusively cause cancer in hosts. Signup and view all the answers

Study Notes

Lecture 1: Introduction to Virology

The lecture is titled "Introduction to Virology" and was presented by Dr. Jasmin Chahal on November 1st, 2024.
The course is MIMM 211 (Introductory Microbiology).
Interactive polling will be used (Slido).
The Slido code is #3031727
Lecture slides will be posted a day ahead of the lecture
All the content for the final exam is contained within the lecture slides.
The lecture will cover: an overview of viruses, virus structure, genomes and classification, genome classification, the infectious cycle, cultivation and detection of viruses, viruses and cancer, and some pathogenic viruses.

Administrative Information (I)

Email: [email protected]
Office: Room 408A, Duff Medical Building
Office hours: By appointment on Calendly (link provided).
Students should describe any steps they have already taken to answer questions regarding course content or assessments.

Administrative Information (II)

Previously taught by Dr. Jacques Archambault
Currently teaching MIMM 324
Research on Human Papillomaviruses
Some slides are adapted from his lectures

Resources

Wellness Hub: mcgill.ca/wellness-hub/ (contact info provided).
Office for Sexual Violence Response, Support and Education: mcgill.ca/osvrse
Laptop loaning: mcgill.service-now.com/itportal?id=kb_article&sysparm_article=KB0010885 (Audiovisual Equipment loans, 2 business days' notice).

Viral Evolution/Origin

No definitive explanation for the origin of viruses exists.
Viruses might have originated prior to or from cells ( ~ 4 billion years ago).
Viruses may have arisen during an "RNA world" period, when RNA was the sole genetic carrier.

Why Viruses Appeared?

Viruses enriched genetic diversity in hosts by facilitating gene transfer.
Earliest viruses may have coexisted with host cells (later possibly harming them).
Viruses may have played a crucial role in the RNA to DNA transition.
Some RNA viruses evolved DNA genomes to protect them from cellular ribonucleases.
DNA is more stable than RNA.
Viruses use cellular replication machinery to replicate.

Viruses are Everywhere!

Viruses occupy nearly all organisms.
They can live in various habitats (air, ocean).
They affect bacteria, fungi, animals, plants, and humans.
They are the most abundant microorganisms.
There are ~94% of nucleic-acid-containing particles and only ~5% of total biomass.

Climate Change Affecting Pathogenic Diseases

Climate change might shift geographic ranges of ~3,100 mammal species, also impacting the viruses they carry.
Increasingly driving encounters between mammal species, risking new diseases.
In the next 50 years, could drive more than 15,000 new cases of mammals transmitting viruses to other mammals.
58% of human infectious diseases have been (at some point) influenced by climatic hazards.

General Characteristics of Viruses (I)

Viruses are genetic elements that reproduce only inside living cells.
They're not living organisms and can't independently reproduce.
They're obligatory intracellular parasites, needing host cells for energy and metabolic intermediates.

General Characteristics of Viruses (II)

Viruses have an extracellular state (virion), containing a protein coat (capsid) surrounding nucleic acid.
Some viruses have a phospholipid envelope (nucleocapsid).
Some may contain glycoproteins as projections.
These projections allow the virus to recognize and bind to host receptors/cells.

Discovery of Viruses

The term "virus" (poison) was coined in the late 1800s.
In 1886, Adolf Mayer's work showed that tobacco mosaic disease was transmissible.
In 1892, Dimitri Iwanowski filtered sap from diseased plants, finding the infectious agent passed through filters that retained bacteria.
In 1946, Wendell Stanley received a Nobel Prize for isolating, characterizing and crystallizing TMV.
In 1957, Sarah Stewart connected some viruses to cancer development.

Giant Viruses

Mimivirus (2003), a "mimicking microbe" was discovered.
Mimiviruses were initially mistaken for bacteria, but their large capsid (~400 nm ) and protein filaments containing ~100nm, distinguishable them.
These viruses have a large DNA genome (~1000 genes).
Called Nucleocytoplasmic Large DNA viruses (NLDV) and can replicate inside the host's nucleus and cytoplasm.

Giant Viruses Challenging Evolution

Giant viruses infect eukaryotic unicellular organisms like amoebas.
Their genomes are diverse and complex
Some genes in giant viruses may have originated from bacteria, archaea, or other viruses.

Giant Viruses Have Their Own Viral Parasites

Virophages are small DNA viruses that replicate only in cells already co-infected with giant viruses
Sputnik (discovered virophage), replicates in Mimivirus-infected amoebas, reducing replication of Mimiviruses by ~70%.
Virophages may improve the host cell survival by preventing cell lysis by giant viruses.

Are All Viruses Bad?

Most viruses aren't pathogenic; they're crucial elements in many ecosystems and regulate population diversity and evolution.
Viruses that infect bacteria (bacteriophages/phages) can be used in phage therapy.

Most Viruses Are Not Pathogenic

Biologists estimate trillions of viruses in and on our bodies (10x bacteria).
While some cause illness, most don't.
They play an essential ecological role in controlling bacterial populations.

Studying That Suits You

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Description

This quiz covers the key concepts from Lecture 1 of MIMM 211, focusing on the fundamental aspects of virology. You will explore virus structure, classification, the infectious cycle, and the relationship between viruses and cancer. Prepare to delve into various pathogenic viruses as well.

Introduction to Virology - MIMM 211

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