Hello, and welcome back to ACMI Fun Facts. This time around, we've got some fast facts about one of nature's slowest creatures, the sloth. There are two types of sloths. Two-toed and three-toed spread across six species. Their slow speed is due to their low metabolism, which allows them to digest their plant-based diet over a period of a few days. Moving slow is still very tiring for little guys, which is why they sleep as much as 15 hours a day.  Sloths haven't always been so small. In fact, in prehistoric times, they were gigantic creatures called megatherium. Megatherium got to be as big as 22 feet tall and weighed as much as 7 tons. The craziest part is that they may have been alive as recently as 11,000 years ago. A smaller version existed called Megalons, which measured 8 to 10 feet and weighed a maximum of 800 pounds. What's truly interesting is that the name for these creatures was proposed by Thomas Jefferson, based on fossils found in West Virginia. That's all for today, but keep your eyes peeled for another episode of ACMI Fun Facts.


So, Dr. Seena Fisher, welcome to the soba. Thank you for having me. Come and tell me about your research that you're exhibiting here. Yes, so we studied the chocolate making process and in particular one aspect of that and that's the fermentation. So, I brought you here a cacao pod, this is sort of the outside, they come in a lot of different shapes and sizes and colors, some are red, some are green. And we cut one open here for you to see the inside, so these are the cacao beans and they are surrounded by this pulp. You can see a little bit better here, it's sort of moist and white initially and it contains a lot of sugar and if you smell the inside of these beans, the inside of this pod, what can you smell? It smells quite fresh, quite nutty, fruity, citrusy maybe, but certainly doesn't smell like cacao. No, no chocolate whatsoever. No chocolate whatsoever. In comparison, if you smell these beans, so these feel much more dry than what we just had there. It's almost like quite a stringent, quite sort of sour, almost like coffee. Yeah, so this is certainly much more nutty and much more going into the direction of chocolate already, so we're getting close here. Now the difference between this fresh bean, these fresh beans coming from the pod and these drier beans is that these were fermented, fermentation is of course microbes acting on food or other products, in this case the cacao beans and changing them in a way. And yeah, this has been a process that has been utilized by farmers for ages to make chocolate in the end. Without the fermentation, you could roast these beans all you liked, you would never be able to turn them into chocolate. They would remain very bitter, these citrusy flavours would remain predominant and you would not get the chocolatey taste. So in the production making process of chocolate making, that fermentation process is crucial to the flavours that we love in chocolate. Absolutely, yes. So where does the science come in then? We study this process. We investigate which microbes are present during the fermentation and how they change. The fermentation is usually done, not usually it's done at the farms, so the cacao is harvested by farmers and these beans and the mucusy like pulp are scooped into big wooden boxes and then the beans are left there to ferment for about five days. And after that time they would have this colour and they would be placed outside to dry and then they're ready to shipment to the chocolatier and then they would proceed with further refinement steps. And a good chocolatier is able to really tease out all these great notes in the chocolate, but if they get low quality beans there's nothing they can do about it. So the fermentation is really crucial in this process and what we want to know, if we have chocolate that tastes fruity, has berry notes and we have a chocolate in comparison that has more floral notes or almost tastes like vanilla, then what was the difference during the fermentation? So sort of reverse engineering almost, working out what happens during that process, what microbes were acting to create that fermentation. And then I guess if you want to in the future purposefully create certain flavours in a chocolate you would be able, you would know what bacteria or what microbes are required. Exactly, yeah it's much more complicated than let's say for example wine making because as you know wine is also fermented but here we need yeast and it's mainly yeast. There are a lot of different yeast strains known to brewers and they would even cultivate them and add them to their certain wines. Although yeast is already growing on the grapes themselves so it's not technically required but they can refine it this process. But for the fermentation of cacao we've noticed that if you just add yeast for example you would not be able to produce these cacao notes and if you just add bacterias of certain kind you would also not get these different flavours. What you really need to have is a specific combination and of course if I start to combine only three things it goes up but we have we have studied this in several thousand samples now and we see hundreds and difference of microbes during the fermentation. Their profiles change from day one to day five. In concert with that the pH changes, the temperature changes on all of these are important factors so it's just it's a much more complicated process. A very complex process and so are those the microbes that are responsible for the fermentation are those present they must be present presumably sort of in the bean or in the place in which the beans are coming from so do you see bacterial variation in terms of where the beans have grown and is that the sort of root of the different flavours. It's an excellent question yes so we asked this as well because it wasn't known right so this process was completely not studied scientifically. Farmers have a certain ability to control fermentation by stirring changing temperature and so on and so forth but what we did was we went to Columbia and to Trinidad and we work with farmers there they are usually small farms family run and we were asking them well would we be allowed to participate in your harvest and take samples so we went we took samples from the surface of the pod from the inside of the pod from the boxes that the fermentation is occurring in and then throughout in order to answer these questions and basically the answer is they're everywhere and they are very diverse between different farms so not even say Columbia has a different microbiome to Trinidad but a specific farm in Columbia has a very specific microbiome and this is why if you want to have really impressively unique experience in tasting chocolate you need to buy a single origin chocolate because there you get these unique flavour developments and these fine flavour chocolates also have the characteristic that they don't taste the same throughout so you start tasting a piece of chocolate and it would start out maybe a little bit bitter a little bit sour but then this would fade away and you would get all kinds of other notes coming through and this is characteristic for all fine flavour chocolate as soon as you start to bulk which is what you get in bulk produced chocolate you lose that characteristic so yeah it's sort of blend if in a blend you wouldn't get those specific flavours super interesting and how does your research impact the people that are responsible for growing the beans you know farmers that are working on this does your research help them in any way this is our goal yes so we work with as I mentioned these small farmers actually the majority of cacao especially in South America is grown on small farms so for them if the fermentation doesn't go quite well and produces what we call off flavours which could be a very bitter notes or sometimes almost moldy tastes then they the quality of the bean would be much lower than they would like and they'd have to sell it at a less price than they need to basically sustain their businesses so our hope is by correlating flavours and microbes we would be able to advise them on best practices how do they avoid these bad fermentation outcomes sure dr. Cina Fisher from the University of Nottingham thank you for explaining the science of chocolate to me and I wish you all the best with your research thank you very much thank you


I mean, does it look like I'm bringing people back from the dead? Like I'm in the business of bringing people back from the dead. Is that what we do here in the cremation ground every day?  Make it something useful, like, yeah, fine, I mean, give me that mantra, give me that power anyway to bring people back from the dead like you offered, because maybe one day I might want to experiment with that as well. Give me maybe a pair of magic dice so that every time I gamble, I will always win. Give me that and you have a deal. The friend agrees, so Akrit goes back to his house, he kills his brother because that's the only Brahmin he can lay his hands on very easily.  Kills his brother, brings him back to his friend who promptly gives him both the mantra with which to bring people back to life as well as a pair of magic dice.  He doesn't need to use it just now, but he goes straight to the casino and he gambles all night and to his great delight, he wins every single game. He's absolutely thrilled, he makes lots of money, settles down at a brand new house, everything is wonderful, but then one night as he's coming back from the cremation ground, he notices on the funeral pyre a half burnt corpse. And he starts to wonder that this mantra that he has to bring people back from the dead, does that only work if the body is complete or will it also work if the body has been burnt? I mean like will this magic mantra put the body back together and then bring it back to life? I mean it's worth thinking about and it's worth experimenting with. And so Akrit stands over this half burnt corpse and he starts to recite the mantra, but he's barely even started when suddenly he notices that the left leg of the corpse has started to twitch. The right side the body was the one that had been burnt, but the left side was still whole. The left leg has started to twitch and before he can even move the left eye has suddenly flown open and the left eyeball has started to rotate wildly in its socket. Akrit gets such a fright that he leaves the body where it is, he leaves the mantra as it is half finished and he makes a run for it. And he runs as fast as he can till he gets back to his house, locks the door, pushes all the furniture in front of the door and goes and hides under the table, shivering and shaking, hoping and praying that no harm will come to him. Now he sits under that table for a couple of hours and then he starts to think that maybe he overreacted, that certainly that half burnt corpse, that half alive corpse is not going to come looking for him, but just as he thinks that the door handle rattles and the door is pushed open and in walks the half alive corpse, shuffling along on its left leg, the dead right leg hanging behind him, the left eye going wild in its socket, muttering something under its breath. Akrit almost dies with fright but he's not going to wait to find out what the corpse is trying to say to him, what it's actually muttering under its breath. Behind him there's a window, he jumps out that window and once again he makes a run for it. He runs through the night, he runs through the following day till he gets to the next town and when he gets to the next town he finally breathes a sigh of relief because he thinks well that half alive corpse on that one leg is not going to be able to find me over here. I will be safe finally. Once again he settles down to his new life, he's got his magic dice so he goes to the casino, he gambles every night, he wins every game he ever plays, makes lots of money, buys a new house, makes new friends, settles down but one night as he's sitting in the casino with five of his friends the door of the casino opens and in walks that half alive corpse shuffling along on its left leg, its dead right leg hanging behind him. By now the flesh on the right leg has become so rotten that it started to hang off it. The left eye is still going wild in its socket, the muttering has now increased almost to a growling, it's sounding really angry. The five men who are sitting in the room, they take one look at the corpse and they die of fright where they are sitting. They literally just fall to the ground, die of fright. Akrit doesn't die of fright, he's seen this corpse before, he doesn't die of fright but once again he doesn't want to know what this corpse wants from him. There's a window again behind him, jumps out the window and once again he makes a run for it. He runs for several days without stopping, without even looking back to see what's happening till he gets to the next kingdom and once he gets to the next kingdom he figures actually this time I really will be safe because this is truly too far for that corpse to catch up with me. So with his magic dice he goes back to the casino, makes lots of money, buys himself a new house, gets himself a new mistress, settles down to a wonderful new life. But one evening as he's sitting in his new house with his new mistress enjoying her company, the door of the house opens and in walks that half alive corpse shuffling along on its left leg, the dead right leg hanging behind it and by now the flesh on the dead right leg has become so rotten that even the maggots have gotten into it. It's a petrifying sight. The left eye is going wild and it's socket. The growling has become even angrier. What had started off as a muttering. By now it's sounding really furious. The poor mistress takes one look at the corpse and she dies of fright where she is. Akrit as before doesn't die of fright when he sees the corpse but he still doesn't want to confront the corpse so as always there's a window behind him.  He's sitting on the second story so when he jumps out of this window which is on the second story he falls all the way to the ground below and is dashed to death. Weird story, definitely. What happened to the corpse before somebody asks? I don't know because the story doesn't say so. Is there a lesson to this story? Always. And what is that lesson? It's about understanding the importance of finishing what you start. About having the self-discipline to finish what you start. I guess it's based on the idea of Akrit not finishing the mantra when he's bringing the corpse back to life. About him leaving it halfway because it just became too difficult for him to do and I think unfortunately this is something that we're all guilty of at some point or the other. You start something and then either it becomes boring or becomes too difficult to do or somebody else is doing something that seems like so much more fun and we decide not to finish what we've started and then we justify it by saying that surely it's better for me to leave what I'm not enjoying and actually pursue something that is going to make me happier. Actually no. They say that this habit of not finishing what we start or this habit of jumping from one thing to the other is one of the main causes behind mental health issues. It's one of the main reasons behind depression because a mind that is full of unfinished thoughts it becomes a cluttered mind and it leaves you no space in there for peace. And so although it might seem like a really small thing that I started this but now I want to move on because I'm bored with this and what's the big deal? It is actually a big deal. The thoughts that you do not finish the thoughts that you do not lay to rest I find over time it starts to get toxic. You know just like in the story you have the corpse and every time you see it it started to rot and decay a little bit more. The same thing happens with everything inside your head and so the thoughts that are not laid to rest over time they become so toxic that they actually become like poison inside and so this idea of the importance of finishing what you start is all about decluttering the mind. It's all about understanding how to remove that poison from your mind, the toxins from your mind so that every day you can start afresh because you know what your mental health begins and ends right here. You can do all the yoga, you can do all the meditation that you want but it's all about what goes on over here and this has to be kept pristine. It has to be kept uncluttered and pure.


Dear students, in this topic we shall discuss the mechanisms of hormone action. The action of hormone can be divided into two phases. First, the formation of a hormone receptor complex. In the second phase, the hormone binding to the receptor produces the effect and this phenomena and this series of chemical reactions, this produce the response, which produce the response from the second phase of hormonal action. First, we shall discuss the formation of hormone receptor complex, which is the first step of a hormone action. During this, the hormone binds to a specific receptor at the target cell. This binding results in the formation of hormone receptor complex. Dear students, the receptors of hormones are large proteins. Every target cell may have about 20,000 to 100,000 receptors. Cells, who do not have receptors like this, do not bind to them. To bind to the hormone, only a few cells have receptors like this and other cells do not have receptors like this, which is the reason for the specificity of the hormones. Dear students, now we shall discuss where the hormone receptors are located in the cell. The receptors for lipid insoluble hydrophilic water soluble hormones, for example, catecholamines, protein and peptide hormones are present in the plasma membrane. These hormones being lipid insoluble cannot penetrate the cell, so they bind to the surface receptors. The steroid hormones and lipid soluble hormones can enter in the cell, so their receptors are present inside the cell. The steroid hormones have two receptors in a cell, the primary receptors are present in the cytoplasm, while they have secondary receptors inside the nucleus. The steroid hormones being lipid soluble can easily enter into the cytoplasm and bind to the receptors which lie inside the cell. So lipid insoluble hormones cannot enter in the cell, so they have to bind to the plasma membrane because they cannot enter in the cell. But steroid hormones can enter in the cell, so they can bind with the cytoplasmic receptors. The steroid hormones and lipid soluble hormones are thyroid hormones, thyroxine and triadothyronine. These hormones are found in their receptors in the nucleus and are not present in cytoplasm. Dear students, now we shall discuss the phenomena that produces response. The formation of hormone receptor complex initiates a cascade of reactions in the cell. These intracellular reactions and mechanisms vary for the hormones which bind to cytoplasmic receptors or to the plasma membrane receptors or to the nuclear receptors. Now we shall discuss the mechanism of action of lipid soluble hormones. The lipid soluble hormones which bind to the cytoplasmic or nuclear receptors make the hormone receptor complexes which translocate finally into the nucleus and there they act directly on the DNA causing changes in gene expression. Such effects are long term and may last for hours to days. The mechanism of action of lipid insoluble hormones is different from those of lipid soluble hormones. Their binding to cell membrane receptors leads to the production of second messengers. The second messengers may be one or more than one in this series. The third messengers amplify the signal and the response produced is rapid but short lived and may last for a few minutes to a few hours. This effect is produced through the activation of different effector proteins. Dear students now we shall discuss the mechanism of action of prostaglandins. Prostaglandins are lipid soluble hormones however they bind to the cell surface receptors and produce a rapid and short lived response which is similar to that of lipid insoluble hormones.