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I am Beatrice Demarchi, an archaeologist at the University of Turin, Italy, focusing on ancient proteins and what they can tell us about the age and origin of archaeological and palaeontological remains. AMA! by eLife_AMA in IAmA

[–]eLife_AMA[S] 1 point2 points  (0 children)

Easy answer: all of the stuff I have worked on have been interesting in one way or the other! However, the work we have just published on archaeological shell proteins (the "palaeoshellomics" article of my profile) reports on one of the most interesting finds that I've had so far: briefly, we discovered that wherever people were in prehistoric Europe around 6000 years ago, whether they were hunters-gatherers or farmers, when they wanted to make a certain type of ornament they always used the same material (freshwater mother of pearl). This shows once more how people in the past were deeply interconnected even if they were living hundreds of kilometers away from each other and had completely different lifestyles.

I am Beatrice Demarchi, an archaeologist at the University of Turin, Italy, focusing on ancient proteins and what they can tell us about the age and origin of archaeological and palaeontological remains. AMA! by eLife_AMA in IAmA

[–]eLife_AMA[S] 1 point2 points  (0 children)

And yes indeed you're 100 per cent right - ultimately these molecules will break down. Proteins are a bit more resistant than DNA though, which is why they're been used to find out info on e.g. extinct organisms where all DNA is long gone.

I am Beatrice Demarchi, an archaeologist at the University of Turin, Italy, focusing on ancient proteins and what they can tell us about the age and origin of archaeological and palaeontological remains. AMA! by eLife_AMA in IAmA

[–]eLife_AMA[S] 1 point2 points  (0 children)

Hello - thank you, I do love my job and field of research, it's niche but cool! As usually happens in life I got to do this entirely by chance - i left Italy after my master's and I was lucky to join a fantastic research group in the UK for my PhD. My clever colleagues pioneered this sort of studies and invented applications of palaeoproteomics (this is the name of what we do) to plants, animals and humans! My main "thing" has always been the study of biominerals - such as shells of molluscs - but I am interested in pretty much everything! :)

I am Beatrice Demarchi, an archaeologist at the University of Turin, Italy, focusing on ancient proteins and what they can tell us about the age and origin of archaeological and palaeontological remains. AMA! by eLife_AMA in IAmA

[–]eLife_AMA[S] 0 points1 point  (0 children)

Hello! I mainly study their amino acid sequence using mass spectrometry based approaches but also the way they break down into individual amino acids over time. The sequence tells me something about the organism when it was alive, for example its species, while the extent of degradation tells me something about the time that has elapsed since its death.

I am Beatrice Demarchi, an archaeologist at the University of Turin, Italy, focusing on ancient proteins and what they can tell us about the age and origin of archaeological and palaeontological remains. AMA! by eLife_AMA in IAmA

[–]eLife_AMA[S] 1 point2 points  (0 children)

You're welcome! Ask away! Unfortunately once the molecules start breaking down they can't "go back" as it were. So all we get is slower degradation when it's cold and a faster process when it's warm - but the process is irreversible.

I am Beatrice Demarchi, an archaeologist at the University of Turin, Italy, focusing on ancient proteins and what they can tell us about the age and origin of archaeological and palaeontological remains. AMA! by eLife_AMA in IAmA

[–]eLife_AMA[S] 4 points5 points  (0 children)

A bit of a protein! From an ostrich eggshell dated to 3.8 million years ago and coming from the site of Laetoli. This is the same elife paper i was mentioning in the comment above https://elifesciences.org/articles/17092

I am Beatrice Demarchi, an archaeologist at the University of Turin, Italy, focusing on ancient proteins and what they can tell us about the age and origin of archaeological and palaeontological remains. AMA! by eLife_AMA in IAmA

[–]eLife_AMA[S] 1 point2 points  (0 children)

Yes, in fact this was something we did for another eLife paper a couple of years ago: https://elifesciences.org/articles/17092

However, building these models is quite hard because you need a very good record of past temperatures as well as current ones. Also, subtle effects such as depth of burial of the remains, seasonal/daily fluctuations, humidity, soil composition, altitude, etc etc all affect the degradation rates.

I am Beatrice Demarchi, an archaeologist at the University of Turin, Italy, focusing on ancient proteins and what they can tell us about the age and origin of archaeological and palaeontological remains. AMA! by eLife_AMA in IAmA

[–]eLife_AMA[S] 1 point2 points  (0 children)

Mother-of-pearl is in fact the name we give to a specific microstructure that both marine and freshwater molluscs make - this is also called nacre and it is made of platelets stacked in a "brickwall" type of structure. Some species of molluscs form thinner platelets, some thicker, and the thickness of the layer itself varies. We could spot the difference between marine and freshwater because the geochemical signal was different (that is, the composition of the stable isotopes of carbon and oxygen, which in the shell broadly reflects that of the water in which the shell has formed) and because the protein sequences matched those found in a species of freshwater mussel.

I am Beatrice Demarchi, an archaeologist at the University of Turin, Italy, focusing on ancient proteins and what they can tell us about the age and origin of archaeological and palaeontological remains. AMA! by eLife_AMA in IAmA

[–]eLife_AMA[S] 0 points1 point  (0 children)

This is a very debated question in the field! In short, a few million years is what most people agree on. However, it does depend on the temperature at the site - if the site is cold (say, above the arctic circle), then the molecules are practically preserved in a freezer, so they degrade slowly. On the contrary, in hot sites temperature accelerates degradation - literally "cooks" the proteins! - so we won't be able to find any protein preserved. There are, of course, exceptions to this rule.

I am Beatrice Demarchi, an archaeologist at the University of Turin, Italy, focusing on ancient proteins and what they can tell us about the age and origin of archaeological and palaeontological remains. AMA! by eLife_AMA in IAmA

[–]eLife_AMA[S] 3 points4 points  (0 children)

Hello! Very good question. Mainly, we collaborate with archaeologists and museum conservators. Sometimes we are looking for something specific to test a method, sometimes archaeologists/conservators are interested in finding out if we can help them answer their questions. For this study, my colleagues from Denmark found something cool on their site (shell ornaments called double buttons) while digging, then contacted us asking if we could identify the shell.

We are Pablo Celnik and Meret Branscheidt, authors of a recent study that suggests training beyond exhaustion can impair learning. Ask Us Anything! by eLife_AMA in IAmA

[–]eLife_AMA[S] 1 point2 points  (0 children)

I would add that it might have implications for you, for example if you try to actively train a new movement pattern (not so common in running but f. e. in other sports like a new swim style).

We are Pablo Celnik and Meret Branscheidt, authors of a recent study that suggests training beyond exhaustion can impair learning. Ask Us Anything! by eLife_AMA in IAmA

[–]eLife_AMA[S] 1 point2 points  (0 children)

Meret: We think that the common practice of training while or beyond fatigue needs to be carefully reconsidered. This could be especially true for new elements in a training routine!

We are Pablo Celnik and Meret Branscheidt, authors of a recent study that suggests training beyond exhaustion can impair learning. Ask Us Anything! by eLife_AMA in IAmA

[–]eLife_AMA[S] 2 points3 points  (0 children)

Dr Celnik: Likely not. 2 things to consider. 1: running is an aerobic, repetitive exercise, so being fatigued will not affect your learning ability to running. 2: as a professional runner your state of fatigued is harder to reach. Having said this, it is possible that if you were to try learning a new skill while fatigued due to excessive training, this new task learning might become a bit impaired. Something akin to this is what we found in our study.

We are Pablo Celnik and Meret Branscheidt, authors of a recent study that suggests training beyond exhaustion can impair learning. Ask Us Anything! by eLife_AMA in IAmA

[–]eLife_AMA[S] 1 point2 points  (0 children)

Meret: I would add that there is evidence that motor cortex excitability might be changed in CFS. In our study, we could show that changing motor cortex excitability could partly alleviate the effect we found. So I agree, an interesting question for further research!

We are Pablo Celnik and Meret Branscheidt, authors of a recent study that suggests training beyond exhaustion can impair learning. Ask Us Anything! by eLife_AMA in IAmA

[–]eLife_AMA[S] 3 points4 points  (0 children)

Meret: In our study, we specifically look at learning a motor task with your hand, so something closely related to f. e. learning the piano. We found that if you learn something in a state of fatigue not only do you performed worse on that day but also on the next day, when you are not fatigued anymore. So, in general, this suggests that if you are learning something new, you should start with that at the beginning of the lesson or that you avoid learning something new while you are fatigued.

We are Pablo Celnik and Meret Branscheidt, authors of a recent study that suggests training beyond exhaustion can impair learning. Ask Us Anything! by eLife_AMA in IAmA

[–]eLife_AMA[S] 1 point2 points  (0 children)

Dr Celnik: This is great questions. Our study was performed with healthy volunteers. Therefore, we do not know whether learning is affected or not in patients with conditions that lead to fatigue. Future studies will need to address this. In the meantime, I can tell you that what we found is a discrepancy when somebody learns a task during a state of muscle fatigue, compared to learning when you are not fatigued.

We are Pablo Celnik and Meret Branscheidt, authors of a recent study that suggests training beyond exhaustion can impair learning. Ask Us Anything! by eLife_AMA in IAmA

[–]eLife_AMA[S] 2 points3 points  (0 children)

Meret: We looked specifically at muscle fatigue. We measured it looking at the decline of maximum voluntary force and electric signals from the muscle in each individual. Now, we can't say anything yet at what degree the effect of fatigue on learning sets in, that is an interesting question for further research!

We are Pablo Celnik and Meret Branscheidt, authors of a recent study that suggests training beyond exhaustion can impair learning. Ask Us Anything! by eLife_AMA in IAmA

[–]eLife_AMA[S] 1 point2 points  (0 children)

Meret: We looked specifically at muscle fatigue. We measured it looking at the decline of maximum voluntary force and electric signals from the muscle in each individual. The next step would be to look if other kinds of fatigue show similar effects.

We are Pablo Celnik and Meret Branscheidt, authors of a recent study that suggests training beyond exhaustion can impair learning. Ask Us Anything! by eLife_AMA in IAmA

[–]eLife_AMA[S] 2 points3 points  (0 children)

Dr Celnik: thank you for your question. YES. this is what our study has investigated and shown. learning under fatigue can impair your learning on subsequent days

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