PARASITES BENEFIT THEIR HOSTS -- AT THE INDIVIDUAL LEVEL

 

Parasites Benefit Their Hosts — At The Individual Level

Post #36

Donald A. Windsor                                                                                                      

Parasites are usually regarded as nasty symbionts that harm their hosts. The articles by Harris and Wickramasinghe and by Hu et al. show that some helminth parasites can actually benefit their hosts by inducing the production of antibacterial agents, in this case the SPRR2A protein. So, perhaps these helminths are not parasites but are some other form of symbiont.

Changing their designation is not merely a trivial argument over definitions. A fundamental puzzle I have been trying to solve is why parasites manage to survive. Why are hosts unable to evolve ways to render parasites extinct? An arms race is the usual answer, but I have a different one.

Parasitism is a property of life.

Life on Earth that is. A great deal of research is being done on trying to find extraterrestrial life. Will parasitism also be a property of that life?

References cited:

Harris, Nicola ; Wickramasinghe. A helminth-induced antimicrobial protein. Science 2021 November 5; 374(6568): 682-683.

Hu, Zehan ; Zhang Chenlu ; Sifuentes-Dominguez, Luis ; Zarek, Christina M. ; Propheter, Daniel C. ; Kuang, Zheng ; Wang, Yuhhao ; Pendse Mihir ; Ruhn, Kelly A. ; Hassell, Brian ; Behrendt, Cassie L. ; Zhang, Bo ; Raj, Pithvi ; Harris-Tryon, Tamia A.; Reese, Tiffany A. ; Hooper, Lora V.

Small proline-rich protein 2A is a gut bacterialcidal protein deployed during helminth infection. Science 2021 November 5; 374(6568): 710.

Windsor, Donald A. Parasitism as a property of life. Parasites Dominate 2013 September 3; Post #2. parasitesdominate.blogspot.com

Windsor, Donald A. Parasitism on Mars. Parasites Dominate 2015 November 8; Post #10. parasitesdominate.blogspot.com

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ARE PARASITES SINGING THEIR OWN UNCEASING SONG OF LIFE?

Are Parasites Singing Their Own Unceasing Song Of Life?

Post #30

Donald A. Windsor

Well, parasites may not be singing, but they sure are showing off their most visible presence – biodiversity.

James Lovelock referred to the infrared signal of the oxygen-methane disequilibrium radiating from Earth's atmosphere as an "unceasing song of life".

"This unceasing song of life is audible to anyone with a receiver, even from outside the Solar System." (1).

If Lovelock's statement is correct, then this song would indicate life on any extraterrestrial entity.

After such life is found, perhaps it could reveal whether parasitism is, or is not, a universal property of life. I suspect that it is.

Here on Earth, our life exhibits parasitism. But, what would life look like without parasitism? I suspect that the signature hallmark of life is biodiversity. But biodiversity can result from life adapting to environmental forces, such as competition, predation, habitat, and climate.

Parasites enhance biodiversity by thwarting monocultures. Therefore, the absence of monocultures on extraterrestrial entities could be a signature of parasitism.

However, how would a monoculture be recognized? On Earth we have no naturally occurring pure monocultures; they exists only in labs or buildings. Our so-called monocultures, such as with agricultural crops like corn and wheat, always have other species living among them.

Here is a handy metric that I propose. In a monoculture, the number of individuals of one species is at least 1 magnitude higher than the total number of individuals of all the other species combined, in the same area.

For example, if a bean field had 10,000 individual bean plants, then it would be a monoculture if the total number of individuals of all the other species in that field was under 1,000, a difference of 1 order of magnitude.

This metric would not be able to compare macro-species with microbial species, because the microbes would always outnumber the macros. However, it may be useful in comparing a monoculture of a microbe with other microbial species.

So, while the unceasing song of parasitism may not be a song, it may be an image visible to anyone with a viewer.

Reference cited:

1. Lovelock, James. The Ages of Gaia. A Biography of Our Living Earth. 2nd Edition. New York, NY: Oxford University Press. 2000. 268 pages. Quote on page 7 of the Introductory.

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DEEP SUBSURFACE BIOSPHERE ─ ANY PARASITES?

Deep Subsurface Biosphere ─ Any Parasites?

Post #27

Donald A. Windsor

As even more information comes in on the deep subsurface biosphere, the more I wonder about generalities already made about our surface biosphere.

The deep subsurface biosphere is composed of archaea, bacteria, and eukaryotes that live underground down to great depths, even under the oceans (1 - 6). It could have more species than our surface biosphere does (2).

Six years ago I proposed that parasitism was a property of life on Earth and if it is found on extraterrestrial planets, it would be a universal property. If it were not found on other planets, then it would be a property of Earth alone (7).

So far, I have not uncovered any reports of parasites in the deep subsurface biosphere.

In 1998 I proclaimed that most of the species on Earth were parasites (8). If there are no parasites in the deep subsurface biosphere, my hypothesis would be nullified. However, I did say "on" Earth, not "in". Nevertheless, I meant "on", because I was not aware of how massive the deep subsurface biosphere is.

Another thought I advocated is that parasites produce biodiversity by stopping monocultures before they get too large (9). Some of the colonies in the deep subsurface may have monocultures. That in itself could indicate a lack of parasites.

I find this all very exciting because I thought that finding extraterrestrial life on Mars would be a test of my hypotheses (10). But now the deep subsurface biosphere may provide that test.

References cited:

1. Lawton, Graham. Earth's deep, dark secret. New Scientist 2019 May 11; 242(3229): 42-45.

2. Klein, JoAnna. Deep beneath your feet, they live in the octillions. The New York Times 2018 December 19.

3. Purkamo, Lotta. et al. Diversity and functionality of archaeal, bacterial, and fungal communities in deep archaean bedrock. FEMS Microbiology Ecology 2018; 94: 1-14.

4. D'Hondt, Steven; et al. Presence of oxygen and aerobic communities from sea floor to basement in deep-sea sediments. Nature Geoscience 2015; 8: 299-304.

5. Magnabosco, C. et al. The biomass and biodiversity of the continental subsurface. Nature Geoscience 2018 October; 11(10): 707.

6. Puente-Sánchez, Fernando. et al. Viable cyanobacteria in the deep continental subsurface. PNAS 2018 October 16; 115(42): 10702-10707.

7. Windsor, Donald A. Parasitism as a property of life. parasitesdominate.blogspot.com 2013 September 3. Post #2.

8. Windsor, Donald A. Most of the species on Earth are parasites. International Journal for Parasitology 1998 December; 28(12): 1939-1941.

9. Windsor, Donald A. Role of parasites in Earth's biosphere. parasitesdominate.blogspot.com 2017 September 30. Post #13.

10. Windsor, Donald A. Parasitism on Mars. parasitesdominate.blogspot.com 2015 November 8. Post #10

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PARASITISM ON MARS

Post #10

PARASITISM ON MARS

Donald A. Windsor

Parasitism is a property of life on Earth, because most of our species are parasites (1). However, what about life on other worlds? We are on the verge of discovering life on Mars. Will Martian life have parasites?

If parasitism is a universal property of life, then it should occur in Martian life.

If Martian life does not have any parasites, then parasitism is unique to Earth. It would have to be decided on how many potential host species would have to be examined before it could reasonably concluded that no parasites occur.

Meanwhile, we should avoid contaminating the Martian biosphere, in case it has one.

1.  Windsor, Donald A.  Most of the species on Earth are parasites. 

 International Journal for Parasitology 1998 December; 28(12): 1939-1941.

PARASITISM IS A FORM OF PREDATION

Donald A. Windsor

Post #3

From the beginning, life seems to have been based on the consumption of nutrients.  The wide range of different processes for obtaining those nutrients is reflected by the vast biodiversity on Earth.  Many organisms have specialized in obtaining nutrients by consuming other organisms through predation.  Many parasites prey upon other organisms by an intimate form of predation.

Needless to say, but predation harms the prey and parasitism harms the host.  The differences between predation and parasitism are dependent on the situation.  Predation can be fatal to animal prey whereas it is usually not fatal to plant prey. 

I am not merely playing with words here.  The distinction between a predator and a parasite became very real to me when I was working with an undeniable parasite, Paragonimus kellicotti, a lung fluke in mammals.  This trematode ingested host blood from its position in its host's lung. 

I wondered how its tetrapyrrole metabolism compared to that of the blood-sucking leech, Hirudo medicinalis.  I wanted to use the leech as an easier to raise stand-in for the fluke.  But is this leech a predator or a parasite?  Is the female mosquito a predator or a parasite?  Mosquitoes consume a blood meal in just a minute or so.  In my lab, leeches fed on guinea pigs for a few hours to over a day.  The lung fluke can persist in place for years.  Is the difference between a predator and a parasite a mere matter of time?  Or is it internal versus external?  How about a blow fly maggot eating dead flesh on a living host?  Or an ichneumon wasp larva developing in a live caterpillar?  What about fleas and ticks? 

If it is difficult to make a distinction between predation and parasitism, then perhaps there is no distinction, just a spectrum.  If indeed that is the case, then because predation is certainly a property of life, parasitism is also a property of life.

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PARISITISM AS A PROPERTY OF LIFE

Donald A. Windsor,   Norwich, NY                                                          Post #2

If every living species were either a host or a parasite or both, then there would be no doubt that parasitism was an integral property of life.

Unfortunately, every living species has not been studied to the depth necessary to ascertain this information. However, enough species have been, so it does seem reasonable to make this assumption.

Why bother? Because the opportunity to see if this property is restricted to Earth, or is universal. Mars is currently being investigated. All properties of life should be looked for. If parasitism is found on Mars, then we can be more confident that parasitism is a universal property of life.

If life without parasitism is found on Mars, then we will be able to see why life on Earth carries such a parasitic burden.

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