67 replies to this topic

[erzebet]

Hello everyone,

The topic of ageless animals was quite neglected by gerontologists for many decades. The information on these kind of species is quite rare.
I was thinking of writing a book on this topic gathering a list of mechanisms of how these animals avoid senescence.
For the moment, I am searching data on turtles, Hydra, lobsters, bivalves, jellyfish, planarian flatworms and the naked mole rat. I am using Pubmed searching for scientific articles on longevity, negligible senescence in non-humans.

If any of you knows of any related textbook or article, I would greatly appreciate your help!

[eighthman]

I can only wish you Godspeed on this grossly neglected topic. I fail to understand why it is so poorly supported when it could hold the answers to aging.

[nowayout]

A few years ago there was an interesting article on negligible senescence in turtles in, I think, the New Yorker.

Some whale species also have very long lives.

The hydra has been written about a lot, too much in my opinion, since I don't think its life-cycle really counts as an example of negligible senescence any more than, say, the human germ line's does.

Edited by nowayout, 20 January 2014 - 05:28 PM.

[eighthman]

I trust you are aware of Guerin's work on agelessanimals.org? And harpoon findings on whales ( as to their indefinite lifespan)?

There are some comparative papers written on this topic ( I have copies somewhere). It seems that they have evolved very precise biochemistry to prevent ROS stuff and junk proteins - unlike us.

I think our best hope lies with modulating autophagy.

[erzebet]

wow, 3 replies already!!

indeed, I found many articles on Hydra - especially in the journal of developmental biology - which I do find interesting because of its transdifferentiation strategy in a multicelullar organism.
yes, I am familiar with agelessanimals.org - although the bibliography is not that comprehensive

as regards longevity, I would insist on negligible senescence rather than maximum lifespan. I mean whether the organism has a constant mortality and fertility rate during its lifespan.

[nowayout]

as regards longevity, I would insist on negligible senescence rather than maximum lifespan. I mean whether the organism has a constant mortality and fertility rate during its lifespan.

You mentioned mole rats. Do they have negligible senescence?

[erzebet]

yes, check this article (the abstract of it)
http://link.springer...0360-007-0237-5

[nowayout]

yes, check this article (the abstract of it)
http://link.springer...0360-007-0237-5

I am not sure the idea of and expiring negligible senescence is all that useful, even when they qualify it being true only for the "majority of their lifespan", in this case 24 years of an average 30 year lifespan. By that measure humans would also have negligible senescence if only we all dropped dead at 30 instead of living to 75. After all, humans also have "negligible senescence" for at least the 24 years mole rats achieve. The fact that something goes very wrong with mole rats between 24 and 30 should disqualify them as a "negligible senescence species", given that humans are already out-achieving mole rats by leaps and bounds in holding off senescence after 24. After all, the devil we are trying to exorcise is in the details of what happens after 24, for mole rats as for humans.

What I am trying to say is that negligible senescence that expires is not a useful negligible senescence, since we humans have this already.

As far as I can tell, among vertebrates only some turtles species are currently thought to be candidates for true non-expiring negligible senescence. Now that is something that should be studied more.

Edited by nowayout, 20 January 2014 - 10:36 PM.

[eighthman]

I have heard about Rockfish laying eggs at 200+years and a whale who got harpooned while 'doing it' - who later turned out to be well over a hundred.

[PWAIN]

Observation in mammals would give us the best model. Naked mole rats resistance to cancer would be good to understand in itself. DNA sequencing would also be helpful to get past just speculation.

[erzebet]

From my research till now, I found there are three types of aging patterns:
1 sudden death - right after reproduction; e.g. salmon
2 gradual aging - with different senescence rates according to the species and the individual ; e.g. humans and most animals
3 slow or negligible senescence; e.g. some types of rockfish, sturgeons
The interesting thing is that groups of animals like fish have members belonging to each of these patterns.

[erzebet]

if anyone else is interested on this subject, I just found a database of animal aging and longevity:
http://genomics.sene...e.info/species/

[Bogomoletz II]

From my research till now, I found there are three types of aging patterns:
1 sudden death - right after reproduction; e.g. salmon
2 gradual aging - with different senescence rates according to the species and the individual ; e.g. humans and most animals
3 slow or negligible senescence; e.g. some types of rockfish, sturgeons
The interesting thing is that groups of animals like fish have members belonging to each of these patterns.

There are also animal organisms that regress to a larval state and regrow into adults multiple times. So, if a salmon never reproduced, could he live indefinitely?

[nowayout]

if anyone else is interested on this subject, I just found a database of animal aging and longevity:
http://genomics.sene...e.info/species/

Interesting that quahog clams can live to more than 500 years in the wild.

[erzebet]

From my research till now, I found there are three types of aging patterns:
1 sudden death - right after reproduction; e.g. salmon
2 gradual aging - with different senescence rates according to the species and the individual ; e.g. humans and most animals
3 slow or negligible senescence; e.g. some types of rockfish, sturgeons
The interesting thing is that groups of animals like fish have members belonging to each of these patterns.

There are also animal organisms that regress to a larval state and regrow into adults multiple times. So, if a salmon never reproduced, could he live indefinitely?

no, castrated male salmons may live up to double - read a journal article on this - if interested, I can search for the link.

if anyone else is interested on this subject, I just found a database of animal aging and longevity:
http://genomics.sene...e.info/species/

Interesting that quahog clams can live to more than 500 years in the wild.

well they have a doubly sheltered life - their body produces their shell and they live burrowed under the sand; also they feed mainly by filtering the water for plankton, so they are mostly safe from predators unlike most other shells.
I read that burrowing shells live more than the exposed ones.

[Ghostdog23]

Always liked the giant tortoises

http://www.sdu.dk/en..._12_20_aldring

http://www.nature.co...ature12789.html

https://www.australi...nimals/harriet/

[Bogomoletz II]

no, castrated male salmons may live up to double

That boost to their life expectancy likely comes also from the hormonal consequences of castration. Eunuchs reportedly lived longer.

[erzebet]

The salmon's fast aging rate (almost sudden death rate) is supposedly ruled out by hormones as well.

Ghostdog23, thank you for the links!

[InquilineKea]

How would the negligibly senescent animals find a way to reduce accumulation of lipofuscin and carbonylated proteins?

I mean.. bacteria do it because the ones with more carbonylated proteins would simply die earlier..

So can the hydra find a way to dilute out the cells that have accumulated more of that junk?

[nowayout]

How would the negligibly senescent animals find a way to reduce accumulation of lipofuscin and carbonylated proteins?

I mean.. bacteria do it because the ones with more carbonylated proteins would simply die earlier..

So can the hydra find a way to dilute out the cells that have accumulated more of that junk?

The human germ line somehow does this too already.

[erzebet]

 

How would the negligibly senescent animals find a way to reduce accumulation of lipofuscin and carbonylated proteins?

I mean.. bacteria do it because the ones with more carbonylated proteins would simply die earlier..

So can the hydra find a way to dilute out the cells that have accumulated more of that junk?

The human germ line somehow does this too already.

 

 

Talking about the human germ line and why all babies are born young (no matter the age of their parents) - the best book I read on this question (and it became an obsession for me during medical school) is "Power, Sex, Suicide" by Nick Lane - a book about mitochondria in general which I highly recommend.

Male germ cells are continously produced de novo during the lifetime of a man - even if this production decreases during age.

Female germ cells are produced once and are periodically lost - first as a fetus, then during puberty, and then each month until menopause if unfertilized.

Each female ovum has a mixture of nuclear DNA and mitochondrial one - these two genomes need to function in harmony, otherwise the cell produces no or insuficient energy - this mix-and-match process is what makes the abrupt lose of ova during intrauterine growth and later during puberty. Once an egg is deemed suitable for survival it needs a second copy of nuclear DNA which it gets from the male cell during conception - if the new cell has any severe defect in how the energy is produced, a spontaneous abortion will take place.

 

Now all this "regeneration" by keeping only the cells with "good" nuclear and mitochondrial DNA, as well as bringing in foreign nuclear DNA from the male - while mostly using the mitochondrial male DNA as fuel for the spermatozoid only - is what keeps children being born young.

 

 

[Danail Bulgaria]

Hi!

 

Very nice topic.

 

In many sources, one of which is the abstract here:

http://www.nrcresear...10.1139/z04-174

 

is written, that Cnidarians, that do not age, have a "high regenerative ... potential". This, according to me can be the cause of their ageless. I can speculate, that they simply constantly rebuild and replace their biological structures and remove the aged ones. Equivalent of this in the human body will be that we constantly to grow new blood vessels and to take out of our body the cholesterol clumped ones, or to constantly regrow new teeth, that to replace the abrased or the parodontic ones, or to grow new organs, and to remove old ones, and to constantly produce new neurons in our brains, with speeds higher, than they die every day, and that these neurons successfully integrate in the brain, and this to be valid for all of our cells, tissues and organs. We humans, however can not regenerate like that. The only thng, that we can do is to use our brains to build artifitially cells, tissues and organs and to find a way to replace them successfully in our bodies. E.g., we will have to "think out" a successfull methodes for genetically identic structures transplantation. Something, that I hope, that will come soon would be the cells, tissues and organs made from stem cells and/or by cloning and the methods for transpalnting them periodically and successfully (even if you have the genetically identical organs, transplantation methods for some of them does not still exist). If it becomes true, however, we will be able to mimic the super speed regeneration and structures replacement of the Cnidarians.

 

I gues, that many people, who have been thinking about different ways to live forever, very frequently have been walking through to 2 main points, no matter of the path, that they chose.

 

1. Transplantation - medical term, that means replacement of a biological structure with a bilogical structure. For example kidney transplantation.

2. Implantation - medical term, that means replacing of a bilogical structure with a non - biological structure. For example the dental implants.

 

The stem technologies, and artifitial limbs and cybernisation of parts of the human, are simply the next steps of the development of the transplantation and the implantation in the different areas in the medicine.

[erzebet]

Indeed seivtcho, stem cells are the secret of such species.

 

Given my extensive literature research in this field for the past 6 months I have identified two main patterns in the negligible senescence species:

1. dormancy

2. modular growth (whether through stem cells in animals or meristem cells in the roots of perennial plants)

 

For those interested, here are 3 blog posts in more detail:

http://longevitylett...escence-part-i/

http://longevitylett...scence-part-ii/

http://longevitylett...cence-part-iii/

[erzebet]

I made a lot of progress on this topic. The literature is scattered all around, but in the last months I managed to get some patterns clear.

For those of you interested in the topic, please join the Comparative Gerontology FB group here:

https://www.facebook...83953735071847/

 

The biology of aging is traditionally studied in fast-living organisms such as mice, C. elegans worms and fruit flies.
It is time for gerontology to focus on negligible senescence species as well such as the ocean quahog, several turtles, the red sea urchin, the naked mole rate, the rockfish and many more.
Species mainly prolong their lifespan by decreasing their metabolism and/or by undergoing regeneration of their somatic tissues.

[nowayout]

I made a lot of progress on this topic. The literature is scattered all around, but in the last months I managed to get some patterns clear.

For those of you interested in the topic, please join the Comparative Gerontology FB group here:

https://www.facebook...83953735071847/

 

I would, but I don't do Facebook.  Oh well. 

[lucid]

While the topic is quite specific to animals, i'll mix it up with some plants.

 

Its worth pointing out that almost all perennial plants have negligable senesence (i.e: trees) They still 'get old' and have capped lifespans. This is because though they don't age at a cellular level (aside from accumulation of viral disease), but they do age at a macro structural level (Core rots outs).

 

How do we know they don't age at a cellular level? You can take a clipping of an extremely old tree, put root growth hormone on it... and it will grow again into another old tree. In fact modern agriculture is based on this fact --- much of our food comes from vegitatively propegated plants which are VERY old, much older than any of the individual plants.

 

So why can this happen? The core reason is because the germ line in plants doesnt differentiate from the soma  early in development. I.e: Fruit (and seeds) can grow  from anywhere on a branch... Any cell can differentiate into a reproductive cell. This means that biologically, the plant must protect all the cells from aging to protect the germ line. In humans, since the germ line differentiates early, the soma (body) can be sacrificed.

 

Of course the interesting point here is that the mechanisms to fully control aging already exist in our cells but are only activated in our germ line. Trees on the otherhand have these aging control mechanisms activated in all their cells all the time.

 

Cheers.

[erzebet]

While the topic is quite specific to animals, i'll mix it up with some plants.

 

Its worth pointing out that almost all perennial plants have negligable senesence (i.e: trees) They still 'get old' and have capped lifespans. This is because though they don't age at a cellular level (aside from accumulation of viral disease), but they do age at a macro structural level (Core rots outs).

 

How do we know they don't age at a cellular level? You can take a clipping of an extremely old tree, put root growth hormone on it... and it will grow again into another old tree. In fact modern agriculture is based on this fact --- much of our food comes from vegitatively propegated plants which are VERY old, much older than any of the individual plants.

 

So why can this happen? The core reason is because the germ line in plants doesnt differentiate from the soma  early in development. I.e: Fruit (and seeds) can grow  from anywhere on a branch... Any cell can differentiate into a reproductive cell. This means that biologically, the plant must protect all the cells from aging to protect the germ line. In humans, since the germ line differentiates early, the soma (body) can be sacrificed.

 

Of course the interesting point here is that the mechanisms to fully control aging already exist in our cells but are only activated in our germ line. Trees on the otherhand have these aging control mechanisms activated in all their cells all the time.

 

Cheers.

 

Excellent observation. Plants - especially trees - are able to survive for thousands for years, both individual trees as well as the whole colony. Very few animal colonies are able to do that - and it's mainly sea sponges and the like.

http://longevitylett...ially-immortal/

 

Still vegetative propagation can take place WITH accelerated aging like in the bamboo.

 

 

 

[corb]

Of course the interesting point here is that the mechanisms to fully control aging already exist in our cells but are only activated in our germ line.

 

Unfortunately that's not supported by empirical evidence.
Older humans produce more defective progeny everyone knows that, few people like to read why, I've posted papers about it in one thread or another in the aging theories forum.

In short, there's defective mitochondria creeping into the zygote, failing repair mechanisms in zygotes from old oocytes, extremely long repair cycles taking place in the zygote trying to create a viable fetus which wouldn't have existed if the germline is protected, etc.

 

The statistics of children born with defects and the amounts of in vitro insemination in countries with old parents goes to show the germline isn't safe from aging.

[lucid]

Excellent observation. Plants - especially trees - are able to survive for thousands for years, both individual trees as well as the whole colony. Very few animal colonies are able to do that - and it's mainly sea sponges and the like.
 

http://longevitylett...ially-immortal/

 

Still vegetative propagation can take place WITH accelerated aging like in the bamboo.

 

 

Thanks erzebet - interesting article on sea sponges! I had no idea they were so long lived.

 

What do you mean by accelerated aging like bamboo? I thought some bamboo could be quite old..? Certainly colonal clumps of bamboo must be quite old.. If bamboo is aging rapidly cellularly (vs structurally) then vegitative propagation would result in cellularly old progeny which isnt the case.

[lucid]

I'm having some trouble locating your articles corb, though I will look more later.

 

Interesting points here. So you are of course right that it is well known that as folks get older birth defects etc are much more likely to rise (Primarily relating to the age of the women).

 

What is pretty clear however, is that despite the average maternal age of first birth being 26-29 for most modern countries, our children aren't starting off any older. Even a small accumulation of age from generation to generation (2%) would mean that we start off with a cellular age of 20 from ancestors 2000 years ago. There are other force that can protect this process other than purely protecting the germline from aging such as gamete competition (sperm), natural abortions due to cellular damage, emergency repair in zygote etc vs ongoing repair in oocytes.

 

Another point to consider is that as we age, germline protection may and in fact should shut down. This would account for the remarkably low birth defect rate in young women while explaining increased rates in older women. Continued protection of the germline past a certain age may fall victim to evolved neglect. This opens up the interesting idea that some of 'shutting down' of germ line protection could be triggered by endocryn changes as we age.

 

Unfortunately that's not supported by empirical evidence.
Older humans produce more defective progeny everyone knows that, few people like to read why, I've posted papers about it in one thread or another in the aging theories forum.

In short, there's defective mitochondria creeping into the zygote, failing repair mechanisms in zygotes from old oocytes, extremely long repair cycles taking place in the zygote trying to create a viable fetus which wouldn't have existed if the germline is protected, etc.

 

The statistics of children born with defects and the amounts of in vitro insemination in countries with old parents goes to show the germline isn't safe from aging.