Virology Lectures 2021 #2 - The Infectious Cycle

The infectious cycle is what we call the complete course of events in a virus infected cell. In this lecture we discuss the different parts of the infectious cycle and how to study them, including assay of infectious virus particles by plaque assay, multiplicity of infection, and the particle to pfu ratio. Physical methods for detecting viruses include hemagglutination, serological techniques, polymerase chain reaction, and high-throughput sequencing. We show how these methods were used to identify in early 2020 the new pandemic coronavirus SARS-CoV-2.
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I’m Vincent Racaniello, Earth’s Virology Professor.
I’m also a professor of virology at Columbia University in New York. I’ve been doing research on viruses since 1976, and teaching virology in classrooms and online since 1999. On this KZbin channel I share videos of my lectures, podcasts, and more.
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[@thomasarmstrong5410]

Well, I’m glad I’m not the only one here. It’s incredible that we can attend lectures from the best teachers that work at the best colleges in the world thanks to Covid. For free. I’ve watched this whole series in about 6 days and learned an insane amount of information. Thank you so much for making this available to the public!

[@rchristy5767]

How can I find lectures in other subjects? I bumped onto this one by chance but would love to take advantage of more learning oportunities

[@rebeccafagan2927]

I watched this same lecture from 2020 and I’m really grateful that you’ve tweaked your style to explain what things are and what words mean for people like me with no background in bio science, thanks so much

[@metforminasilanes]

Taken the course twice before... each time it amazes me the simplicity and complexity of the topic. Yet, Professor Racaniello always does a superb job on teaching it. Now updated, and always taught with enthusiasm, wisdom, and purpose. In this COVID 19 era... a must. Thank again to our Professor Vincent Racaniello.🥇.

[@scottydawg1234567]

I love the energy with which you speak on this subject. You are clearly passionate about what you do!

[@JessieVegaPhoto]

Thank you for sharing this information. You are doing a great service for society. Myself and my family are better for it. Our eleven-year-old son is now more knowledgeable about viruses than most adults we encounter. Thank you, thank you.

[@johnbouttell5827]

Part 2 of the greatest series of lectures ever made [unless you understand Richard Feynman's lectures].

[@dashachumaeva133]

I would say that these lectures are so amazing!!!!! I'm doctor from the Czech Republic and it's incredible help for me. Thank you for you work and sharing this information with the public.

[@ScotHarkins]

I love getting lectures where I can tweak the playback speed. Vincent is already a fast talker, but 1.5x sets the pace just right for me. Thank you for the course! Should fill in some holes after watching TWiV, et al, over the last couple of years. Yay!

[@vinnyrac]

Thank You for sharing these with the public. You make this all very interesting. -Vinny Rac

[@thomasrawlinson3496]

I am a practicing internist, seeing a lot of covid patients over past 2 years.Using this course yo update my knowledge of virology. Thank you for a great lecture series

[@JenniB123]

Who on Earth would give this a thumbs down. Excellent lecture! Thanks Dr Racaniello

[@questella]

Probably an antivaxxer

[@mohammedahmedjalloh531]

There are always people for everything mate! Won’t stop us from learning, would it?

[@tski3458]

There is a few antivaxxers around.

[@pavel9652]

Some folks don't believe viruses exist. You know, it is part of secret scientific cabal. Seriously.

[@JenniB123]

@@pavel9652 Flat Earthers! Because scientists have nothing better to do than sit around & make up bull.

[@welshbabe1949]

I did the fundamental course on ALISON in 2012 and having no background in science had to spend hours writing notes about the terms used.....today's course is so much easier to follow with your current explanations to the lay person.

[@decoy80070]

I love these lectures because they always go viral!🎓

[@Th3ForgottenOne]

fantastic video profesor, very well explained. I'm going to start my phD and I'm very interested in being an virus specialist. Thanks!

[@Threshold370]

Your lecture blew my mind. I can feel your passion in virus in your lecture. Thank you.

[@erhnmatthewnavaisip224]

I'm 11 and I m already watching this

[@westfield90]

It’s amazing that so much of this cannot be seen and yet the genius men and women who throughout history have figured this out, Bravo to all these great people past, present and future who expand our knowledge.

[@thevegandragon4676]

Is it 'genius' to sacrifice billions of non-human 'lab' animals to permanent incarceration in barren, uncomfortable, tiny physical environments, ie. cages, and then subject them to torture, physical, mental and emotional abuse, pain and suffering and long, where they rapidly descend into mental illness from the daily torment of their lives and drawn-out painful deaths, when alternatives are available? We seem to live in a world full to the brim with psychopaths in every walk of life, from vivisectionists working in all fields of science, Big pharma, to animal ag, to animal entertainers, ocean destroying chemical companies, and deep-trawler fishing etc etc etc. WTF is genius about any of that! Grow up!

[@junviatorlifeingermany1836]

This definitely helps me understand TWIV much better. Thanks!

[@chemistryinstruments7156]

Very nice with the updated Covid 19 parts, thanks so much!

[@SniperScope99]

I’m a senior in high school and I think this is what I want to do with my life

[@TremendousSax]

Best of luck to you! You've got a great career ahead

[@Frank-sy3li]

Thank you Vincent! This is wonderful!

[@nicoledigruber8965]

oh brilliant, a new lecture. thanks for that.

[@Kingkhan-nt9sq]

sir, I haven't words to appreciate you. you are so great...

[@george7752]

wonderful course doing it a 2nd time did it last year,I highly recommend to everyone to do and gain more knowledge on this topic .. wonderful explanation on the subject of the PCR testing and CT threshold, very relevant at this moment in covid testing and the many false positives ...from Cape Town South Africa..

[@wboyle5899]

Fantastic 2nd episode well worth the watch exellant presentation best wishes from Glasgow scotland

[@christopherrobinson7541]

Also watching, again this year from Livingston Scotland

[@wboyle5899]

Hi Christopher these episodes are so educational hope you are all safe in livingston West Lothian are you on vitimin d? Best from Glasgow

[@christopherrobinson7541]

@@wboyle5899 William, all safe at this end, hoping your are to. How are you getting on with the book? I find that the font in the hard copy is a bit small for my old eyes.

[@danielsanderson3797]

Rekindled my passion for virology. Thanks from Australia.

[@divalatinaprods]

I love it.. do I get a virology certificate if I finish this course.??

[@VanityNutrition]

Are you attending the live course now? It's Mondays and Wednesdays at 11AM EDT. I think he mentioned something about possibly making a certificate. (You may have been kidding, but I'm not! ;-) )

[@powersend]

@20:55 what was done to the non-infected cells? did that have any material at all added to them??

[@starchildo240]

Hi I’m trying to understand why the lack of a control experiment in what you would call virus “isolation” which seems important not to mention scientific if your not actually isolating a virus by definition? Also how can you be so sure that a virus is pathogenic if you’ve never proven a virus to be pathogenic. Thank you. This is a fascinating subject Im and I’m just trying to understand.

[@sonuverma8139]

Sir as you said in measurement of viral enzyme activity slide to perform western blot for filtered viral products that are genetic materials but it must be southern or northern blot, please correct me

[@sonuverma8139]

Sir I have a doubt, according to statement "not all virus are infectious " does that mean from total sample of like IFV not all IFV are infectious? So it basically represent rate of infectivity of a virus. Am I correct?

[@kunshilukas]

Amazing, physicians really need to watch this videos and be a little bit more informed.

[@peterlafontaine2173]

New subject. Do you think the isolation and forced chemical washing will reduce people’s immune system advancement and make them even more susceptible to the next virus?

[@jewelciappio]

Not likely IMO but I’m not a doctor. Viruses cycle through the population and every generation has to be exposed in some fashion in order to develop immunity either through direct infection or acquired immunity through secondary exposure (i.e. from mother to child). If anything it may mean years from now in the next generation there could be another wave of coronavirus, but it’s unlikely there was some other less deadly virus that was prevented becoming a pandemic through us washing our hands and wearing masks. We may have prevented Ebola? 🤷‍♀️

[@biochemksmu]

Proffessor, how i can contact with you? I have a few questions and i think no one can help me excess of you)

[@peteglass3496]

Yay, I finally know what a 'PFU' is after months of following TWiV! I meant to start on Vincent's 2020 course but it's my New Years Resolution now and it's great to be watching the refreshed 2021 lectures. :)

[@HesderOleh]

When I started listening to TWiV many years ago, I figured they were the viral equivalent of CFU (colony forming units), but wondered if I was hearing it correctly.

[@tim2269]

What type of interface would be used to study the Gi MicroBiome ?

[@ambersunset3147]

Thank you SO much for making this accessible!!

[@christopherrobinson7541]

@1:05:03 Phylogenetic Tree. Notice that apart from humans and bats, the only other mammal lineage was for mink, (second up from bottom Mink Cov). Perhaps not "Fear is the spur" but "Fur is the spear".

[@HesderOleh]

That could just be because of what viruses they decided to put in the tree. There are many coronaviruses, so this might just be based on what they chose to compare to.

[@TatianaBoshenka]

At 36:34 there seem to be 140 wells in the 96 well plate. Is that right?

[@HesderOleh]

good catch, until I saw your comment I couldn't figure out why the plate seemed off slightly. A 96 well plate is usually 8 by 12 and is standardized for automatic pipetting.

[@PaulAJohnston1963]

Wouldn't it be interpolation rather than extrapolation for a end point dilution assay?

[@mariehunter3412]

Absolutely fascinating. Thank you for being so clear. I remember the giant picture of the DNA strand on the cover of Life magazine. I can still see it in my head decades later after retiring after 50+ years as a nurse.

[@sandyb1184]

Great presentation! Thank you so much!

[@HesderOleh]

At 1:06:10 when Vincent said that SARS-CoV is more distant and isn't there, he made a mistake. It is in the branch directly under those in red. It is hard to think on the fly, but of course SARS-CoV which is from similar bats to SARS-CoV-2 are more related to each other than to MERS or H-CoV OC43 which are also on this tree.

[@dinahu.s.a.2663]

That is what I thought exactly, but I couldn't see the diagram clearly to zoom in

[@ExistenceUniversity]

16:40 this counters the idea that viruses aren't aware, contradicting yourself from earlier. What is the mechanism that allows virus to be aware of what medium is surrounding them?

[@abusumayah9540]

How do we know the cytopathic effect was caused by the virus and not the laboratory conditions?

[@ifyoureadthisyoudi]

Use a negative control with no added virus.

[@jukker95]

I love to listen to the doc and I appreciate the clear way that he presents lots of information. I am disappointed the he would tell the story of Henrietta Lacks without mentioning the fact that she was Black. It is in important piece of the story and a careless erasure of history not to mention it.

[@hassegreiner9675]

While e is the basis for the natural logaritm, e is not the natural logaritm, ln, per se.

[@luisfernando-mm3jt]

Can the plaque assay be used to kill tumors

[@rosalindmartin4469]

Phew. You make it sound so straightforward. I'll be rewatching T (to the 6th pwr)😅

[@maryrowe506]

Good stuff. Thank you!

[@anjalijadhav8177]

Thank you so much ,,Sir📹 🥰🥰🥰🥰😇😇😇

[@midwestribeye7820]

This is fascinating!

[@kl0f]

Thank you Vincent.

[@benmonette7593]

When he speaks of the cytopathic effect on plaques. He uses CPE, what does that stand for?

[@elle26426]

Cyto-Pathic Effect: CPE

[@benmonette7593]

@@elle26426 thank you!

[@redataha4352]

Great thanks to you

[@fadibitz]

20:38 - They won't say "Wow", but they likely say something close, such as "Wa...!" (哇). "Wa sei!" (哇塞) is another possibility. Also, these lectures are so good and so informative that I watch them almost for entertainment now. I watched the 2020 lecture series several times; Prof Racaniello is so clear in his explanations that you can't help but understand the key points in general if not in detail.

[@concernedcitizen3254]

So has SARS-CoV-2 been found in any bat samples?

[@scodellina5482]

just a comment to improve YT algorithm so more people can find these videos

[@luisfernando-mm3jt]

Thanks for your passion

[@GarryBurgess]

I still don't understand the difference between "fitness" and "transmissibility" and why that is importance to the population.

[@mathmo]

RaTG was not identified in a cave outside Wuhan but in Mojiang ,Yunnan province, South China, 1800 kilometers from Wuhan.

[@mathmo]

^RaTG13

[@fredrickmbui6722]

Excellent!

[@pked9]

LOVE THE NEW 2121 Series.....

[@ianpollard4501]

I was far from a A student in school so I will have to look at this a few more times.🤷

[@acidbubblebath77]

Question: You make many references to the Polio virus. What is it about this particular virus that seems to be of interest to you and presumably, a significant component of your research into virology? EDIT: Typos

[@alexmladen]

Amazing

[@PeterMillerSyd]

You should mention the name , it would only be right

[@mohammedahmedjalloh531]

Here we go again 2021

[@narancauk]

''Infectious cycle''--------------Of what? Of Petri dish infection ?

[@machinegunk5090]

Yes. Infectious from dish to dish. Well probably not.

[@narancauk]

@@machinegunk5090I love ''probably'' !!!!!!!!!!!!!!!!!!!

[@ekulda]

I have a question professor. If a virus is a cleansing agent of toxins in the cells. The RNA created by the body's immune system which contain deleting sequences, protein, enzymes to neutralise the toxins built up in the body. And each RNA is unique in correlation to the genome type (individual), how can my cleaner agent have anything to do with your system? My RNA is meant for cleaning my toxins and not yours. Because that's why it was created by the immune system. The RNA has part of my DNA so that the RNA itself is not considered as a foreign agent. This RNA does the cleansing for my body chemistry. And won't be applicable to another. Can you please explain why should my RNA 'infect' or work on someone else's toxins? Yes if the lifestyle of the other individual is similar to mine and has the same toxins as me, I can understand he/she too may undergo the same 'cleansing' process (commonly termed as viral infections) but again he/she will have a unique RNA. Yes and Why use the word infect too? Oh and by the way, media is created for the Shill effect. Pay no attention to them.

[@pked9]

LOVE IT ....

[@yangsiyuan4]

Saying that RaTG13 came from a cave outside Wuhan is like saying that Houston is outside New York. Mojiang is more than 2000 kilometers from Wuhan.

[@HesderOleh]

Which is why some people think this escaped from a lab. What I think is less crazy is that possibly some researchers got infected when studying bats in the wild and didn't isolate the virus in the lab, but brought it back with them to Wuhan in vivo.

[@yangsiyuan4]

I don't mean to imply anything like that - RaTG13 is not SARS-CoV-2. I just think it's strange that he seems not to know much about the RaTG13 story if he thinks that centers on Wuhan. I mean, it was discussed on TWIV at length.

[@geraldaird9390]

Amni otic surely? Not amni toic.

[@GeraldStewart-v6l]

🎉

[@PeterMillerSyd]

Henrieta Lacks, did not come through...

[@Aloneagainofcourse]

Geez.. I'll never get here first.

[@EastIdahoPhotoCo]

Well, they didn't say "wow" cuz they were in China. Lmfao!!! This is fun stuff, thank you!

[@kotogab]

I started this course and got a virus, laying in bed now. Coincidence? I don't think so.

[@netto682]

FANTASTIC VACCINE 👏👏👏👍🇧🇷

[@PeterMillerSyd]

Sorry,I commented too early, you did...

[@karma-rq6ie]

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