Comments on: Virology lecture #2: The infectious cycle

By: ElDean

ElDean — Wed, 03 Feb 2010 16:15:43 +0000

Of course bacteria has lag phase!, please check it after me Prof.

By: ElDean

ElDean — Wed, 03 Feb 2010 08:15:43 +0000

Of course bacteria has lag phase!, please check it after me Prof.

By: Lisa Ann,RNP

Lisa Ann,RNP — Sun, 31 Jan 2010 21:45:43 +0000

Wonderful Lecture! Do the amyloid fibrils as mentioned in previous post with regards to XMRV/HIV increase the P(k) ?

By: Philip

Philip — Sat, 30 Jan 2010 10:51:10 +0000

When I last read a book on virology, it stated that while some virions were destroyen in low pH, all known viruses could be destroyed by high pH. Is this still true? Is this a significant effect? Would using real soap rather than pH 5.5 soaps help avoid hospital outbreaks of norovirus? How does petrol destroy virions?

Sorry if this is a tad confused. Thanks again for a great lecture, and thanks for making it downloadable so I'm encouraged to listen to it again to see whether that clarifies things.

By: Dr. Patricia Jordan

Dr. Patricia Jordan — Fri, 29 Jan 2010 10:36:50 +0000

Would the vaccination process also be a way that the human genome could now contain 8% viral genes? 200 years of injecting who knows what (as small pox vaccines are thought to be Giant Pox which is cow syphillis) and the introduction of Herpes 1 & 2 and cytomegalovirus, SV 40 and other monkey viruses through polio vaccines……since vaccines are not screened for purity and genetic mutations not looked for in the vaccinated populations. Also how are the chimera viruses that are made and injected into humans and animals grown? They can't be grown in eggs can they since such man ipulation techniques are necessary to even have them exist.

By: gsgs

gsgs — Fri, 29 Jan 2010 09:37:38 +0000

not talking about ambisene. Just wondering why there are different senses and whether
viruses can flexibly switch.
(same for RNA-DNA, budding vs. bursting the cell, envelope or not,…)
Also to your reprogramming strategies … it's interesting how “genetical algorithms”
are implemented with mutations in nature. But our designed computer-algorithms
look superior, so there should be space for improvement
through artificial algorithm-design , so will we see man-made re-programmed “improved” viruses
soon ? And then the military and terrorists will get it …

By: azileretsis

azileretsis — Thu, 28 Jan 2010 18:49:54 +0000

One can talk about the advantages of being negative or the disadvantages of being positive. If one's positive, the virus (anthropomorphizing) has to choose between replication or protein production. By being negative, the virus can do both.

I think with the high rate of virus mutation, it's hard to say which of the different categories of RNA viruses came first.

Are you talking about ambisense viruses which are technically negative strand but also can act as positive strand?

Also, to a comment above, I like working with viruses because they contain so much with so little. Because of this, they serve as good models (pathogen/host) and possibilities in reprogramming (if you think of genes as java classes, you could potentially have the basis for biological programming).

By: Dr. Patricia Jordan

Dr. Patricia Jordan — Thu, 28 Jan 2010 16:56:23 +0000

For this lecture I have the following questions;
Does the use of Phenol Red not have effects to living cells? As Phenol red is linked to renal failure, can theuse of Phenol red affect the living cells used in culture or the virus entities themselves?
Do the plastic petri dishes contain Bisphenol A and are they emitting toxic agents to the living cells or to the virus entities? All of this from the benevolent petroluem industry?
Was vaccination also the start of autoimmune disease in animals and humans?

By: gsgs

gsgs — Thu, 28 Jan 2010 04:33:34 +0000

what's the advantage of being negative ?
can it switch polarity by evolution ?
are there viruses with both variants (which reassort...)

By: azileretsis

azileretsis — Wed, 27 Jan 2010 20:59:47 +0000

I liked these lectures too. I'm going to remember to start any virus replication explanation with polioviruses. Positive RNA viruses are the best place to start when you are discussing the virus replication.

By: gsgs

gsgs — Wed, 27 Jan 2010 04:35:41 +0000

well, it's “CPE= cytopathic effect” (==>burst(polio)) in the course,
in the paper they say “lytic” virusus (–>lysis),
wikipedia says “apoptosis”

By: gsgs

gsgs — Wed, 27 Jan 2010 03:33:06 +0000

edit with disqus didn't work, so I reply to myself

following the links on the right, I somehow found:
http://www.microbiologybytes.com/blog/2008/05/2...
which views it the other way round and questions the role of lysion(sp?) and prefers budding

By: gsgs

gsgs — Wed, 27 Jan 2010 02:10:45 +0000

it stopped with my AOL-browser after 17min , but it worked now with firefox

It was well understandable for me as nonnative English speaker although you spoke
quickly.Graphics also good.Captions would be useful. Internet is better than
real lessons since you can switch back and hear again when you didn't understand
something and you can make pauses for email,eating,telefone,chatting,dicussing.
Of cause, with books you can do that too but students
are maybe not so motivated to read books ?!?

There are so many different viruses with entirely different mechanisms,
and thus -presumably- quite different encodings, which are hard to achieve by mutations.

some enter without receptor
some don't use translation
some replicate in 20min (polio:8h)
some don't need the nucleus
E.g. why "bud" like flu when you can just burst the cell like polio ?
Get into the cell, replicate,get out. There should be one optimal way
to perform this, not dozends ?!

I learned everything about virology by starting with the sequences(flu).
I was really surprised when I first saw the anatomy of the
virus, how complicated it was with these few nucleotides.

Why do bacteria replicate so much faster ? Because they
can eat and divide directly and need no host ?
They need more nucleotides to perform this and thus are larger ?

Will we one day kill all viruses ?
Will military/terrorists one day make more dangerous artificial viruses ?

By: pjenks

pjenks — Wed, 27 Jan 2010 00:48:02 +0000

Wow. Thanks for posting these lectures, I really enjoy them. I think that your “Adenovirus type 5″ slide showing the eclipse vs. latent period (I never knew the difference) is actually a multiple-cycle curve since it shows exponential growth of virus. If it was a one-step curve shouldn't it be linear growth?

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Tweets that mention Virology lecture #2: The infectious cycle -- Topsy.com — Tue, 26 Jan 2010 21:43:27 +0000

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By: profvrr

profvrr — Tue, 26 Jan 2010 16:21:54 +0000

PCR and sequencing are ubiquitous. The others are all used as they
provide different information.

By: gsgs

gsgs — Tue, 26 Jan 2010 16:18:28 +0000

so many different methods surprise me, I'd expected one to become dominant and
outcompete the others

By: gsgs

gsgs — Tue, 26 Jan 2010 16:16:24 +0000

yes,directly from the browser, maybe not enough memory or such.
I'm downloading the file now

By: profvrr

profvrr — Tue, 26 Jan 2010 16:05:48 +0000

Which version, the flash in the browser window? Or the downloadable
versions? They all play fine here.

By: gsgs

gsgs — Tue, 26 Jan 2010 16:01:53 +0000

stops after 16min