Virus!!!!

[hallenrm]

They are not non living. Are they living? Are the two options mutually exclusive and exhaustive?

 

That's indeed a million dollar question! :D Because, to answer this question first of all one must know to distinguish between living and non living; more so to have an unequivocal criteria to call something living.

 

We tried to do it in the thread "what constitutes life?" and discovered for ourselves that it is not very clear, or should I say not at all clear.

 

So, let someone define life first, before deciding, whether a virus is a living or non living organism :cup:

[LJP07]

 

viruses are nothing but crystalline protein forms properly arranged. When close to their host, then they begin to get active.

 

So this way, the viruses never actually reproduced at all. All they did was to throw a bunch of genes at the lump already present in the cell. So what if the bunch of genes is an excellent template for their mass production?

 

 

I was thinking that the Cell replicates, not the virus, the Living Cell replicates the crystalline protein virus as it enters the cell. The living cell replicates the virus as the virus has overtaken the DNA, but all it's doing is entering the Nucleus.

 

Based on this and the fundamental characteristics which state:

 

All living things are highly organised.

They are composed of tiny units called cells.

They grow and they move.

They reproduce and pass on information from one generation to the next.

 

Viruses aren't highly organised, they are made of protein, they don't move unless inside a host otherwise remain dormant, they don't reproduce unless in their host, so on their own, are they living, NO. If they take over a cell are they living, No.

[HydrogenBond]

The cell manufactures mRNA on the DNA. The mRNA is coded by the genes to make specific proteins on the ribosomes. A virus uses the host DNA to make its own mRNA which is then used to make proteins. If all goes well, the virus increases in number, put on their new shiny protein coats and are transported out of the cell. This causes a multiplier affect allowing the expanding virus family to infect more and more cells to make more and more family members.

 

If one looks at a virus in that sense, a virus essentually, expands the affect amount of DNA, to create additional cell capabilities, i.e., the cell can not only do what it did before but now has the ability to do something brand new. Most virus are considered bad, but viri could theoretically add new positive capability to a cell. This would not be obvious since it does no harm and would be assumed to be part of orginal genetics.

 

Virus don't just spontaneouly appear. They have to start somewhere, i.e, in a cell. Does this mean that some cellular DNA, in certain lifeforms, has viral DNA as part of its genetic make-up? It may have been added at some time in the past or may have mutated on the DNA of the cell before becoming a new virus strain.

 

This creates a plausible theory of evolution. Consider if a virus enters one of the cell types of the body. But in this case, it is a positive addition to the DNA allowing that cell type that make a new group of proteins. With continued infection, one now has one organ more advanced than the DNA capability defined by the cells of the rest of the body. It sort of the opposite of say a viral kidney infection making the kidneys worse off than the cells of the rest of the organs. But instead of a negative DNA affect we have a progressive DNA affect in one organ.

 

Just like a kidney infection can cascade and then began to cause the rest of the cells to degenerate, i.e, ionic imbalance will screw everthing up, the progressive DNA causes a cascade affect that causes the rest of the cells to progress toward better genetic capability. For example, a virus that improves O2/CO2 exchange in the lungs will help all the cellls. This then shifts the junk to good genes distribution. The reproductive center than reflects the global progression of the lifeform shuffling genes closer toward the new advanced features.

[Michaelangelica]

Does this mean that some cellular DNA, in certain lifeforms, has viral DNA as part of its genetic make-up? It may have been added at some time in the past or may have mutated on the DNA of the cell before becoming a new virus strain.

(Was this deleted?)

Human DNA has been shown to contain bacterial and insect DNA so viral "bits?" would not be a surprise. Especially as geneticists are using virusus to carry bits of DNA to another 'target' DNA

[Michaelangelica]

This was a suprise

http://www.cosmosmagazine.com/node/886

(quite a long article; worth a read) Cosmos is an excellent Australian Science magazine.

Oceans teeming with viruses

Wednesday, 29 November 2006

by Hamish Clarke

Cosmos Online

 

SYDNEY: Viruses are the most abundant 'life form' on Earth according to U.S. researchers, who have found the oceans are full of the the not-quite-alive entities.

 

A team lead by Forest Rohwer of San Diego State University in California conducted the first global survey of marine viruses, finding a tremendous variety of viruses with more than 90 per cent of their DNA sequences not present in existing genetic databases.

 

"From an earlier perspective of viruses as purveyors of disease and tools of genetic engineering we have realised that viruses are the most abundant 'life forms' on Earth, are crucial cogs in the biosphere and likely harbour its greatest genetic diversity," author Curtis Suttle said.

 

Viruses are scraps of DNA covered in protein that have the ability to commandeer a cell's functions in order to replicate themselves.

Unless they are activated within a cell, they exist in a state of suspended animation and are thus often not considered to be alive in the true sense.

. . .

In the study, which is published online in the open access journal PloS Biology,

. . .

Overall, the authors predict that the world's oceans hold a few hundred thousand broadly distributed viral species.

. . .

The size and diversity of the virome, combined with the fact that throughout evolutionary history viruses have targeted all known life forms, has major implications.

As Suttle puts it, "I suspect that viruses may be an archive of all genetic information on Earth."

[gribbon]

I wouldn’t say they are: although they are similar to “obligate intracellular parasites” they should still be considered as non-living organisms for several reasons:

 

-They are not cells.

 

-Small viruses with only a few genes may be escaped stretches of nucleic acid that came from the genome of a living organism, thus meaning their genetic material may have come from transferable genetic elements (for example plasmids and transposons), that behave in a fashion that can trigger this. (They move around, stimulate, and infiltrate genomes).

 

-Topoisomerases and helicases could also have liberated stretches of nucleaic acid. I think HEG’s might also have this “liberating” potential, but I’ll have to check that.

 

-Poxviruses (which are part of a group of Virsues with larger genomes) could have been small cells which were parasites on larger host cells. Resultantly, retrograde-evolution (or reverse-evolution) would ensure that genes not essential for their parasitic tendencies would have vanished with time.

 

…I’m also pretty sure, that the bacteria Rickettsia and Chlamydia can only reproduce inside host cells, and so are analogous to Viruses in this aspect, which is a contradiction, :hihi: but nevertheless… :pirate:

 

-With the exception of the human cytomegalovirus, the Viral species never contain DNA and RNA. Even the cytomegalovirus contains only fragments of mRNA.

 

- Although they can contain double-stranded DNA, single-stranded DNA, double-stranded RNA and single-stranded RNA, (all of the types), they rarely contain them all.

 

-The nucleic acids can be either linear or a closed loop, but not both like in bacteria.

 

-They do not metabolise. (Though having just said that I also remember that Rickettsia and Chlamydia are also incapable of reproducing outside of a host cell. Damn.:doh:

 

A few contradictions, but a fair amount of evidence against their promotion to the category of living organisms...:pirate: :pirate:

[Michaelangelica]

I wouldn’t say they are: although they are similar to “obligate intracellular parasites” they should still be considered as non-living organisms for several reasons:

 

-They are not cells.

 

-With the exception of the human cytomegalovirus, the Viral species never contain DNA

- Although they can contain double-stranded DNA, single-stranded DNA, double-stranded RNA and single-stranded RNA, (all of the types), they rarely contain them all.

 

-They do not metabolise. (Though having just said that I also remember that Rickettsia and Chlamydia are also incapable of reproducing outside of a host cell. Damn.:hihi:

 

I find it goes against my intuitive sense of 'life' to consider viruses "not alive"

Ok they often don't do a lot of things live things do, until they invade or appropriate the mechanisms of a cell. But could this not be symbiotic life? There are many examples in nature lichens, coral? photosynthesis? and our bodies own friendly bacteria.

 

Why is the sea full of viruses?

What purpose do they serve in the sea?

[somebody]

This goes to the person who started this thread and his question:

 

-viruses are considered not living.

-Outside the host, they are composed on nucleic acid surrounded by protein coat. They have have phospholipid bilayer (host derived) which has glycoproteins (viral derived) that help virus bind to receptor protein on the surface of host.

-Nucleic acid can be DNA or RNA and either of them can be single stranded or double stranded.

-Viruses must need a host to reproduce.

-Viruses are very specific for a specific bacteria, plants and animals.

-Once inside a host, they have different techniques of reproducing.

 

I know all these facts because i am learning about them in my molecular biology class :hihi:

[Michaelangelica]

3D Virus Image Taken At Highest Resolution Ever

March 6th, 2008| Post views: 2,480 views

 

virus

 

Viruses are sub-microscopic infectious agents that need other cells in order to reproduce. In fact, some scientists claim that viruses are not living beings, as they do not meet the criteria of the definition of life, because they don’t have cells; but they do have genes and evolve by natural selection. Still, they can be very harmful to us, so studying and understanding them is a must.

3D Virus Image Taken At Highest Resolution Ever » ZME Science

I was watching the ABC science show last night.

It said 'blue bottles' (A sort of little stinging jelly fish) was made up of four separate, discrete, symbiotic organisms

Amazing eh!

 

So can a virus at least be considered alive when it is symbiotically beavering /working away with a cell's engineering?

[Rade]

Life can be defined as "self generated action mediated by nucleic acids" (my definition). Therefore, by definition, viruses are alive.

 

The concept "life" must first be defined to answer a general question--is such and such alive ? My proposed definition works 100% of the time on earth--it will be fascinating to learn if it also applies to other planets.

[Geneticist12]

they are certainly not living for a virus must be bound to a seperate living cell in order to perform life's activities otherwise it is found in a dormant stage.

[Michaelangelica]

CALICIVIRUS DELIVERS VACCINES IN HUMANS (Science Show: 05/04/2008)

Calicivirus does not infect humans, so it can be used as a vehicle for introducing antigens or proteins. The aim is to make and test vaccines against tumours.

Science Show - 5April2008 - Calicivirus delivers vaccines in humans

Calicivirus delivers vaccines in humans

 

Listen Now - 05042008 |Download Audio - 05042008

 

Calicivirus infects rabbits.

It causes a haemorrhagic disease. The rabbit bleeds from orifices and dies quickly.

Humans are not a natural host for calicivirus so it does not cause infection, so the virus can be used as a vehicle for introducing antigens or proteins from infectious diseases and tumours into humans.

The aim is to make and test vaccines against tumours. Eventually it is hoped to make a vaccine for a tumour which will kick the immune system and make it think there is an infectious disease.

 

Show Transcript

 

So we even need the humble rabbit's help.

How interconnected we are.

How stupid to let any animal go extinct!

[HydrogenBond]

If virus can insert DNA into cells and if this viral DNA did not disrupt the cell, is viral insertion a possible path for genetic evolution? What this would bring to the table, is a sense of direction. Virus typically infect particular types of cells, so there is a high degree of selectivity with respect to which cells can get genetic insertion. Of all the cells in the neighborhood, a particular type of cell is more vulnerable because it adds up to the best cell plus virus combination. It is not a random type thing.

 

This next part is just brain storming so take it with a grain of salt. Let us start with a cell that was selected by a virus, due to their chemical compatibility, such as the AIDS virus picking certain cells while ignoring the rest. If the cell somehow stabilized and changed its output response, such that the viral output, was able to go into internal recycle, then the cell would be able to integrate these genes as part of it new nature. The new stuff in the cytoplasm recycle might cause a secondary genetic response, as the cell tries to stabilize under the stress of too much useless material staying in recycle.

 

An analogy is a house guest, who begins to take over the house. At first the host is being kind but eventually this gets very stressful. To make make living together better for both new rules will appear to take advantage to the best of both worlds. Even a disruptive house guess may have a few unique tricks which are an improvement over the humdrum. But at the same time the owner is the boss and might try to make both comfortable.

 

There is another possible speculative scenario. We investigate virus because they often have an adverse affect, causing sickness. Is it possible the opposite is also true, that some virus can have a positive impact. This would not be obvious since we are not looking for any positive affect. If the cells appear to be fine, there is no need further investigation. The CALICIVIRUS study mentioned is trying to do just this, using a virus to have a positive impact on cells. This could provide a path for evolution that does not have to wait for spontaneous mutations to get a positive improvement in the activity of a cell. The cell would more quickly include this positive change.

 

The last speculative connection is the formation of virus. Virus are not eternal things that have always been. They have a beginning. This suggests the reverse process. The creator cell might go through an early stage of internal recycle, until the affect is amplified to the point of needing to output the virus. The output may imply an energetically unfavorable affect, that requires the virus leave the creator cell to find a specific host. If that host cell can integrate it, the creator cell has indirectly helped it evolve.

 

The analogy is the intrinsic house guest such as a messy son. At first the parents don't mind picking up after him because it is young. But as he gets older and should be helping out around the house, he instead becomes more work to support his bad habits. So they give him his walking papers. He finds another host, such as a friend to share an apartment. With his friend he may come into his own, with the two working out better.

[Michaelangelica]

If virus can insert DNA into cells and if this viral DNA did not disrupt the cell, is viral insertion a possible path for genetic evolution?

It sounds like agood theory to me. I think that our genome contains 'bits' of bacteria & insect genome. I vaguely remember reading that it may contain bits of viral genome as well.

 

 

 

An analogy is a house guest, who begins to take over the house.

As in cancer? The Tasmanian Tiger mouth cancer for example.

 

 

There is another possible speculative scenario. We investigate virus because they often have an adverse affect, causing sickness. Is it possible the opposite is also true, that some virus can have a positive impact.

Another good theory. The fact that we have just discovered how to use this process, does not mean Mother Nature didn't discovered it aeons ago

How old are viruses evolutionarily speaking? They are not the sorts of things you are likely to find fossils of.

. This could provide a path for evolution that does not have to wait for spontaneous mutations to get a positive improvement in the activity of a cell. The cell would more quickly include this positive change.

This could help explain "two speed evolution"

 

The last speculative connection is the formation of virus. Virus are not eternal things that have always been. They have a beginning. This suggests the reverse process

. Not sure I follow you here.

[Michaelangelica]

New kind of killer virus discovered in Bolivia

 

* 01:00 18 April 2008

* NewScientist.com news service

* Ewen Callaway

 

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* Charles Fulhorst, University of Texas Medical Branch in Galveston

 

A team of disease hunters has announced the discovery of a deadly new virus, found in a remote village in South America. Experts say the virus – named Chapare – is probably limited to a small swathe of Bolivia, but urbanisation and climate change could expand its range.

 

"These pathogens will markedly increase the risk of outbreaks with significant loss of human life," says Stefan Kunz, a virologist at Centre Hospitalier Universitaire Vaudois in Lausanne, Switzerland, who was not part of the study.

 

On 4 January 2003, a young farmer and tailor from the Bolivian village of Samuzabeti developed fever and headache. Over the following days, the 22-year-old's muscles and joints started throbbing, and he began vomiting and haemorrhaging blood. Two weeks later, he was dead.

Mystery virus

 

A local doctor, Simon Delgado, had no idea what had killed the patient; tests for known infectious diseases such as dengue and yellow fever turned up negative. As a precaution, Delgado sent specimens to the US Centers for Disease Control and Prevention (CDC) in Atlanta.

 

There, researchers in the agency’s special pathogens branch unpacked the sample in their most secure laboratory.

 

"When you suspect hemorrhagic fever, for safety reasons you have to work in a lab with high containment," explains CDC's Pierre Rollin. He and his colleagues donned ventilated full-body suits when working on the deadly virus – the same precautions taken to study Ebola.

A new beast

 

The CDC laboratory

New kind of killer virus discovered in Bolivia - 18 April 2008 - New Scientist

[Ahmabeliever]

:eek:

 

Wow, hydrogen bond and michealangelica - good food for thought I was a bit disappointed the thread stopped there...

 

So correct me, I'm here learning...

 

A virus contains dna and assimilates this dna into a cell host. It then replicates by having the cell it is in pass on dna to the next cell.

 

Q. Must the host be a multicellular organism or will a virus affect/select something like bacteria?

 

The viral/dna data bank contained in the oceans really has me interested. I think there is merit to viruses being a key player in evolutionary progress.

[freeztar]

A virus contains dna and assimilates this dna into a cell host. It then replicates by having the cell it is in pass on dna to the next cell.

Basically, yes, but this wiki does a better job of explaining it than I can.

Viral replication - Wikipedia, the free encyclopedia

 

Q. Must the host be a multicellular organism or will a virus affect/select something like bacteria?

Specialized viruses, called Bacteriophages, target bacterial cells. Research is being done on how to use these viruses to combat unfavored bacteria such as E. coli.

 

The viral/dna data bank contained in the oceans really has me interested. I think there is merit to viruses being a key player in evolutionary progress.

 

There is definitely merit!

Check out this fascinating article:

Annals of Science: Darwin’s Surprise: Reporting & Essays: The New Yorker

 

:)