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Hey guys! Its Burt back again with another exciting post. Sorry it’s been a while! I’ve been busy taking care of Toni as she has been sick for the past few weeks. I hope you all have been able to stay healthy during the COVID-19 pandemic. Surprisingly, we get sick just like humans, although our response to a pathogen is a bit different. You see, our immune systems are split into two types of responses; innate and adaptive. Innate immune responses are the body’s general immediate response to a pathogen, while the adaptive response works more slowly and is more specific. This means that adaptive immunity mounts responses that are specific to the type of pathogen attacking the body while the innate immune response generally fights pathogens the same way regardless of the type or class of pathogen threatening it. If we compare innate and adaptive immunity to COVID-19, the innate response would be similar to the first responders, like doctors and nurses that work extremely hard to treat patients, while the adaptive response would be comparable to a vaccine deigned to specifically protect the body from the virus.
Because innate immune responses are more primitive, they are more similar between fishes and mammals like humans. Most of the innate responses are identical between us! On the other hand, adaptive immune responses are somewhat different between fishes and mammals. One major difference between our adaptive immune responses is that we, fish, don’t have lymph nodes which are a part of the lymphatic or secondary vascular system. The lymphatic system is responsible for draining fluids from organs of the body. Blood vessels of the scientists that study us sometimes leak fluid into their organs as blood circulates throughout the body. To prevent the buildup of fluids, their lymphatic system takes the accumulated fluid, and filters it in lymph nodes before introducing it back into the bloodstream. Because this fluid can contain pathogens that reside in tissues throughout the body, mammalian lymph nodes contain immune cells that contact and fight against these pathogens. Instead, Toni, Tyrone, me, and all of our fish cousins have clusters of cells in our spleens called melanomacrophage centers (say that 3 times fast!) that scientists believe have similar functions to their lymph nodes.
Another major difference in the immune response between fishes, like Toni and I, and mammals is that fish do not have bone marrow. I know, it’s so strange! In mammals, bone marrow is where immune cells are made. In us, our immune cells are generated in the anterior portion of our kidneys, in an organ called the head kidney, located, well, as you can guess, in our heads right behind our super smart brains!
So, Toni’s spleen and kidney have been working overtime to fight off her infection and assure that she stays safe and healthy before we let her out of quarantine! If you are interested in learning a little more about the differences between the immune response in fishes and mammals, check out the papers below. Then be sure to check back here in the future for more details on how the scientists are specifically studying our immune systems!
Lieschke, G. J. and N. S. Trede (2009). “Fish immunology.” Curr Biol 19(16): R678-682.
Steinel, N. C. and D. I. Bolnick (2017). “Melanomacrophage Centers As a Histological Indicator of Immune Function in Fish and Other Poikilotherms.” Front Immunol 8: 827.
Hello everyone, Tyrone here to give you an update on our exciting science comic! One of the scientists named Rose worked really hard to ink all 20 pages of the comic recently. Now that it’s done, they’ve been able learn some interesting things from students who have read it I wanted to share it with you all!
Just a quick reminder from a previous blog, scientists gave a pre- and post- questionnaire to students chosen to read certain materials to see whether or not there’s a difference in their attitudes towards science and how much they learn from a comic book versus more traditional formats. Students were randomly selected to read either: 1) a scientific journal article, 2) a ‘news-type’ summary of that article, 3) the comic book, or 4) nothing (the control group). The comic (of course starring myself, Burt, Toni, and Gilgamesh), journal article, and ‘news-type’ summary all told the story of how social defeat in us males has impacts on our behavior and brain, similar to what the scientists refer to as ‘bullying’ in humans.
For today’s blog, I’ll share some results on learning gains (how much readers learned from reading each format) from a group of non-science major undergrad students who participated in this cool study last Fall.
And guess what?, students who read the comic book had the highest learning gains! While students who read the scientific journal article also had high learning gains, it was still slightly less than that of the comic. Students who read the news summary had a moderate learning gain. Lastly, students who read nothing had a negative learning gain! What this tells the scientists so far is that students who read the comic book and scientific journal article were able to learn and remember more about the material they read than the other groups. I was surprised that the learning gains for the ‘news-type’ summary were lower than the scientific article, but thinking about it, it makes sense that anyone would remember more about something they had to put effort into reading rather than just skimming. Most exciting was how well the comic did – supporting my (and the scientists!) idea that the language and graphics of comics might be better than only text writing by itself in portraying concepts that the scientists deal with all the time while doing science!
For now, I’m excited for the scientists to keep running this comic study. It’s been a lot of hard work, but so far it has received very positive reactions and we all believe it will help people from any background become more interested in science in the future! The next step is to publish the comic book and make it accessible and freely available to the public like all of you so you can learn about this research too! I hope you enjoyed the update and keep an eye out on the blog for when it’s eventually released!
Hello, Tyrone here! You know what’s not fun? – Being bullied and harassed over long periods of time. I’ve been picked on by dominant males before, especially Burt, and because of it I wanted to better understand the effects of this constant bullying on the behavior, brain, and overall health of a fish like me.
Luckily, the scientists are interested in this too! They study the effects of repeated bullying using something called a resident-intruder paradigm. Males of our species are either dominant (like Burt) or subordinate (like me, Tyrone). Dominant males are brightly colored and aggressively defend their territory from rival males like me. In a resident-intruder paradigm, there is a tank divided into two territories by a solid barrier. One side contains an intruder male, and the other side contains a resident dominant male who is slightly larger than the intruder. If you place the intruder male into the resident male’s territory, he will be socially defeated by that resident. What does social defeat look like, you ask? An intruder male is socially defeated when he stops trying to fight back and starts performing coping behaviors like freezing or swimming away or hiding, while the resident continues to be aggressive. Scientists can use this set up to study just one instance of bullying or repeated bullying over time – called chronic social defeat!
Here’s where it gets interesting. If a male is socially defeated over a long period of time, even after given a break from being bullied, there is a good chance his coping behaviors might change! If I were trying to get Burt to stop bullying me, I would cope by using a mix of strategies such as being aggressive and attempting to escape or freezing, hiding, and not trying to escape sometimes. What would be really strange is if I did nothing but freeze when in the presence of Burt. But that’s exactly what the scientists saw for some of the chronically defeated males!
So far, it looks like males who are chronically socially defeated can be divided into two different groups: 1) unaffected or resilient (will use a combination of different coping strategies like me!) or 2) reactive or susceptible (exclusively freeze as a coping strategy). As a result of long-term bullying these susceptible males display a behavioral abnormality and may be less successful with the ladies.
Scientists also found differences in the brain of resilient and susceptible males! A brain network called the social decision-making network mediates a lot of social behaviors in many different animals – including stress coping behaviors in response to bullying. Using a neural activation marker called pS6, scientists found differences in specific regions of this brain network between resilient and susceptible males, which is pretty cool!
For example, in a region called the anterior thalamic nucleus (ATn), control males that were not socially defeated had some activation, but not as much as in the socially defeated males! Also, in the superior raphe nucleus (SR), found in the hindbrain, scientists see a lot of activation in non-socially defeated males and almost none in the socially-defeated males.
Overall, scientists are able to show some of the negative behavioral impacts of this repeated social defeat, which can influence how successful males like me might be in the future when we try to challenge males like Burt to take over their territory. This includes better understanding how the brain regulates different coping behaviors in response to bullying, which is something that happens in lots of animals that live in a dominance hierarchy like monkeys, or even humans! One day this knowledge could also be used to better understand human psychiatric disorders such as depression and PTSD!
Check back in the future for more updates on this research project!
Hello fans! Toni asked me, Burt, to tell you all about this new study she and her other gal pals were involved in, and I have to admit it’s pretty cool! Did you know that underwater noise pollution has been increasing over the past few decades? With more and more noise from boats, underwater drilling, and other human-generated activities, it’s getting pretty noisy for us fishes and other aquatic animals! So how does this underwater noise affect our behaviors and physiology you ask? Well, as usual, the scientists designed an experiment to test how noise impacted the ladies when they were mouthbrooding. They played loud noises from an underwater speaker during the mouth brood period and found that it impaired maternal care behaviors in mothers because lots of them either ate their babies or prematurely spit them out! These mothers also had high levels of a stress hormone called cortisol, and different expression levels of genes involved in maternal care behaviors and feeding in a specific region of the brain called the hypothalamus. So these are some pretty negative impacts on these moms! But what about the baby fry that were developing in their mouths during the noise exposure? Well, the scientists examined them too and found that after they fully developed and were released from their mom’s mouths’ they had higher mortality, lower body condition, slower growth rates, and altered behaviors compared to controls that were not exposed to noise. These fry exposed to noise in their mothers mouth also had altered gene expression in their heads compared to controls. So a single exposure to loud noise has really negative impacts on mothers and their fry babies on many levels! This research provides more information on how noise has detrimental effects on fishes like us, which can ultimately lead to reduced reproductive fitness and biodiversity – Toni and I sure hope humans can learn from this and try to reduce the noise levels in oceans and lakes where we live!
Here’s the research paper that describes this experiment in detail:
Butler, J.M.and K.P. Maruska. 2020. Noise during mouthbrooding impairs maternal care behaviors and juvenile development and alters brain transcriptomes in the African cichlid fish Astatotilapia burtoni. Genes, Brain and Behavior. 20: e12692. link
Hey y’all, it’s Toni here! Now that the boys Burt and Tyrone are done telling you about their cool news, me and the gals have some even cooler updates for you! The scientists have been pretty busy learning some new things about the brains of us females. Sit back, grab some popcorn, and I’ll tell you 3 different short stories from the Geaux Girl Fish Power group!
Story #1: So you may remember that us females are mouthbrooders and we hold our developing babies inside our mouths for a couple of weeks. It’s kind of a drag because during this time, we can’t eat, because we’re such good mothers and we don’t want to eat our kids!, so we’re essentially in a starvation mode. But how do our brains control these behaviors of feeding and caring for our babies? Well, the researchers did an experiment to identify which regions of our brain were involved in feeding compared to maternal care. To do this, they used a neural activation marker called pS6 (they mentioned what that stood for, but it’s not really important for the story, plus, I forgot!). This marker shows which neurons in our brain were activated or ‘turned on’ when we were in different conditions. They compared groups of us females that were mouthbrooding (so starved and with a brood), ones that were starved without a brood, and ones that were fed without a brood, and then they looked at the patterns of neuron activation in like 16 different regions of the brain (I bet that’s why the paper they wrote about it has so many authors)! What they discovered was that some brain regions were more associated with the female’s energetic status (starved or fed), other regions were associated with maternal care, but the majority of regions showed involvement of both energetics and maternal care. This was pretty cool because it shows how complicated the regulation actually is and how tightly linked our feeding and mouthbrooding activities really are! The researchers say there’s evidence for both distinct and shared brain circuits involved in regulation of our maternal care, food intake, and energy balance. We’re excited about this too because it will help other scientists in the future to better understand the evolution of how the brain controls feeding and parenting, which is important for all animals that take care of their babies in some way!
Story #2: In this story, the researchers wanted to look at specific neurons in our brains called AVT cells. AVT stands for arginine vasotocin, which is a protein hormone that is involved in regulating many different behaviors, responses to stress, and salt and water balance in the body. Humans have this hormone also, but it’s called AVP, or arginine vasopressin (and sometimes also called antidiuretic hormone because it regulates how much water is in your body and how much you pee). We’ve already talked about peeing in the past, so you know that us girls and those boys are constantly peeing at each other, so yeah, we’re pretty much swimming around in a bunch of urine! – thank goodness for our wonderful filtration system! Anyway, back to this story, which is not about peeing. First, the researchers used several different staining techniques to label these AVT neurons in the brain (one method labels the AVT protein in the cell and another method labels the messenger RNA that will be made into the protein) and found them in several cell groups with funny names based on how big the cells are – gigantocellular (these are giant!), magnocellular (these are medium sized), and parvocellular (these are small). They also found another group of cells in a different brain region called the ventral hypothalamus, and these cells are larger in our brains when we are mouthbrooding compared to when we’re ready to mate. This result was pretty cool because it means that these neurons might help us with maternal care and taking care of those wriggly babies in our mouths – they are certainly a lot of work, and we have to starve ourselves while making them happy! Those gigantocellular cells I mentioned earlier are also even more gigantic as we get further into our mouthbrooding stage, so this may help us get ready to take care of our little kids once they’re ready to go out into the world and we let them out of our mouths – this is also lots of work for us mothers since we have to protect them from the hungry mouths of other fish by letting them back into our mouths for protection! Most previous studies on AVT were done in males (what else is new?!), but Wow, this study shows that these AVT neurons are pretty important in us females too!
Story #3: The researchers looked in our brains for a specific enzyme (proteins that help with chemical reactions in the body) called aromatase. Aromatase is important because it takes the hormone testosterone and converts it to estrogen, which is a very useful hormone for lots of body functions, particularly for us ladies. They found aromatase all over our brains!, and this make sense because fishes have the greatest ability to produce estrogen in their brains out of all animals! – pretty cool! And get this, it’s not found in neurons, but in glial cells! Glial cells are important for maintaining healthy neurons and brain function, and actually, there are way more glial cells in our brains (and your brains) than there are neurons! (we girls think that’s especially true for Burt, but that’s another story!). Anyway, the scientists also measured the levels of aromatase in different regions of our brains and found that it changes with our reproductive condition – in other words, my brain aromatase levels are higher when I’m looking for a mate, am gravid, and have large eggs in my ovaries, and then levels are lower when I’m brooding those babies in my mouth! While they saw changes in aromatase levels, there were no changes in the receptors that bind the newly made estrogen (called estrogen receptors). So, this local production of estrogen in specific regions of our brains may help us females in several ways: improve our ability to sense those crazy courtship displays from the boys, help us make decisions, prepare our brains for when we have to take care of our kids inside our mouths, and potentially lots of other things! Another awesome thing about this project was that there was an undergraduate researcher from another University (University of Louisiana, Monroe) that helped out with it – we love meeting and seeing new faces around the fish room!
Here’s the research papers that explain these experiments and results in detail:
Maruska, K.P., Butler, J.M., Field, K.E., Forester, C., and A. Augustus. 2020. Neural activation patterns related to energetic status and maternal mouthbrooding in an African cichlid fish. Neuroscience. link
Butler, J.M., Anselmo, C., and K.P. Maruska. 2020. Female reproductive state is associated with changes in distinct arginine vasotocin cell types in the preoptic area of Astatotilapia burtoni. J Comp Neurol. link
Maruska, K.P., Butler, J.M., Anselmo, C., and G. Tandukar. 2020. Distribution of aromatase in the brain of African cichlid fish Astatotilapia burtoni: Aromatase expression, but not estrogen receptors, varies with female reproductive state. J Comp Neurol. 528: 2499-2522. link
Hello everyone! Tyrone, here! I’m sure you all love reading Burt’s blog, but what if things got a bit more artsy around here? I’m excited to announce my upcoming masterpiece in the making – a comic book starring myself, Toni, Burt and some friendly new fish faces.
Why a comic book you ask? While Burt uses writing and this blog to share what he and the scientists are up to, I’m more of a visual guy. I LOVE comics!!! But most people assume they’re restricted to superheros or one style of art (although a Superfish sounds pretty awesome). Comics are actually a sequential art where the shape, size, and relationship between panels conveys just as much information as the text itself. They’re really good at portraying abstract concepts in science that are difficult to convey with words – so I thought I’d give it a try!
I’ve turned a big wordy science article published in the Maruska lab into a comic for you readers. I’ve worked really hard storyboarding and sketching a draft for you all. I’ve started the final process of inking everything and once that’s done that’s when the real fun will begin. Like I said, I’m more of a visual guy so not only am I working on this because I love art, but I think I could use it as an educational tool as well! I can use this opportunity to test whether or not readers engage in learning about science more when it’s presented in a traditional format, such as a scientific journal article, or my more untraditional comic book.
I’ll be giving a pre- and post- questionnaire to students chosen to read certain materials to see whether or not there’s a difference in their attitudes towards science and how much they learn! Students will be selected to read either: 1) a scientific journal article, 2) a ‘news-type’ summary of that article, 3) the comic book I’ve created, or 4) nothing (the control group). I’m rooting for my comic to be just as educational as the journal article, but way more fun!
As the star character in this story I don’t want to give too much away about the plot – but like Burt’s blog my goal is to share what fun and exciting discoveries go on in our lab with you all – just in my own unique way. To get everyone excited, here’s a sneak peak at a couple of pages I’ve finished. Only 18 more to go – then on to publication and fun science for the public!
Hello! It’s Burt again. Today, my researcher friends took me outside the lab for a photoshoot. My friends wanted to be able to look at us cichlids outside of the water (why anyone would want to go there, I don’t know). They told us they wanted to make a 3D model of our species, and they chose me to be their study template! We visited LSU’s Communication across the Curriculum (CxC) office and the LSU Engineering Department, where they had me waggle my tailfin for their 3D scanner, and I learned about the 3D scanning and printing process.
3D scanning is the process of using a laser and cameras to analyze an object’s shape, size, and color. As the laser moves over the object, the cameras record the change in distance of the laser. The computer then uses the data to make small triangles or squares in 3D space, in what is called a “point cloud” model. Information from one side isn’t enough, so the scientists asked me to spin around for them so they could take images from lots of angles! After we got all the pictures, I watched as they had to “align” the separate images, putting together a puzzle using the colors and shapes on my body as references. Sometimes, the model is left with holes, so the computer uses a complex algorithm to estimate the shapes of the missing pieces to complete the image.
Guess what else? The researchers also wanted to have a model of my brain!, so they took to a program called Sculptris to digitally “sculpt” a model of my brain so they could print that out too. I heard them say that my brain is pretty similar to theirs in a lot of ways, but since I’m much smaller than they are they needed a bigger version of it to study and teach everyone else how cool our brains are!
Finally, we were ready to print, and my friends and I went back to the CxC office and Engineering department. LSU’s 3D printer is what is called a fused deposition model. The printer is able to deposit, or “extrude”, liquid plastic onto a surface. As soon as the plastic leaves the nozzle, it hardens onto the surface. By depositing this plastic layer by layer, a model is built up. After printing, it takes a soothing dunk in a solution to remove the dissolvable support plastic that held up the Burt model during printing, and then it’s done! I look even better than I thought I did!
The scientists can then also paint the printed models to look flashy and colorful like me, totally drabby like Tyrone, or even classy like Toni. Now, the scientists in the lab will be able to conduct different types of experiments with a ‘model Burt’ and also teach everyone about us cichlids and how our brains work using their newly-printed models. I can’t wait to show Toni!
Now that you know we also use pee and olfactory signals to communicate with each other, I want to tell you about another experiment designed to test how the neurons in our brain work to understand these smells. The scientists put these little needles called electrodes in specific regions of our brain, and then pass water that contains different types of smells (or odors) over our noses to see how our brain responds. When the neuron they’re recording from gets important information from our olfactory epithelium, it fires what’s called an ‘action potential’ (this is caused by ions like sodium and potassium crossing the cell membrane through channels). The researchers can then compare this firing activity after application of these different smells to determine which ones might be most important to us!
In the first experiments, they’re doing these recordings in us males. Right now, I’m a dominant male, meaning that I successfully defend my territory, mate with the ladies, and sport this flashy bright coloration. But I wasn’t always dominant, and in fact, most of the other males in my home town, like Tyrone, are subordinate – they don’t have a territory or mate, look pretty faded, and get chased around a lot by dominant guys like me. Not only do we behave and look differently, but there are also lots of physiological differences between me and Tyrone. So, the scientists are asking whether the olfactory-sensitive neurons in our brains process smells differently when we’re dominant versus when we’re subordinate. Some of the smells they’re testing are amino acids (found in food) and steroids (found in urine). But they’re also testing more complex mixtures of chemicals that might actually be released from us fish. To get these fishy smell solutions, they place either a few ladies that are ready to mate, or a dominant male into some water and let them hang out for a while. Then they collect that water, which contains all of the smells released through the skin, gills, or through peeing!, and put them on our noses while they record from the brain.
What they found out is really cool! – it looks like us dominant males respond really well to lots of different smell types, but especially to the steroids and that water that held the females! When we’re dominant, our brains are more responsive to smells released from females, allowing us to better detect them and stimulate our courtship and mating dances. The subordinate males on the other hand are less responsive overall, but they did show more neurons that were responsive to the odors released from other males. This may help males like Tyrone to better distinguish the dominance status of the other males in the area. Since Tyrone and the other subordinates are always looking for a chance to get a territory home and become dominant, this olfactory ability may help them better gauge which males are wimpy and which are macho. This is pretty cool and useful because it tells them which males to avoid (so they don’t get beat up) and which they should challenge with a higher probability of winning and getting a territory!
So, my brain and Tyrone’s brain are pretty different, but each one is perfectly-suited to perform all of the tasks we need to do when we’re dominant or subordinate. This research is important because these types of brain differences may also exist in lots of other animals that also have dominance hierarchies, from bugs to even people!
Here’s the research article that explains the study details and results:
Nikonov, A. and K.P. Maruska. 2019. Male dominance status regulates odor-evoked processing in the forebrain of a cichlid fish. Scientific Reports 9:5083. Link
Hey guys! It’s Burt again back with more fun science for you to explore. Last time I told you a little about smell and how it helps me communicate with Toni and other fish in my environment. We saw how the delivery and reception of chemical odorants dissolved in the water are important in mediating social interactions. Just as it’s important for me to communicate with Toni and other fish, it’s also important that systems throughout my body are able to communicate between each other, particularly the immune and nervous systems.
Just like you, my brain allows me to take in information from my environment, process it, and produce an appropriate response. Although this process takes a lot of energy, I’m able to do this fairly well, which is great because I need to perform a variety of behaviors like finding food, dancing for the ladies, defending my territory, and protecting myself from predators. But recently, I’ve been more concerned with how well I’ll be able to perform these basic functions in the future.
You see, some environmental changes like pollution and climate change, can negatively impact my normal physiology. This includes sustaining the factors that help me maintain homeostasis (keeping a constant & stable body environment) so that I can properly evaluate my surroundings and perform those behaviors I mentioned before. My immune system helps to keep me from getting sick in these changing times, but I worry that this stressful lifestyle may also have negative effects on my brain and body!
Because I’m a dominant macho male, hormones like testosterone circulate throughout my body, allowing me to properly perform crucial behaviors. Smaller, less dominant males have much lower levels of testosterone. So that this makes a little more sense, let me introduce you to my not so good friend, Tyrone. Tyrone is far less colorful than I, much smaller, and not nearly as attractive! I’m able to protect my territory from other males like Tyrone that might try to steal it, but whenever I leave to forage or find mates, Toni tells me that he quickly takes advantage of the opportunity by adapting my phenotype (i.e. bright coloration), but as soon as I return he becomes subordinate again. Pretty deceptive trick, Tyrone!
How might physiological differences between myself and Tyrone mediate different immune responses? I talked to Teisha, another graduate student in the Maruska Lab, about my concerns and she says she is on the move to investigate the interactions between the nervous system and mounting an immune response! She believes that addressing these types of questions would also be helpful in understanding immune interactions in other species, even humans! Fish and humans actually have many similarities in our immune responses, one being inflammation which is common in many diseases impacting humans today like Alzheimer’s, arthritis and even diabetes. I feel better already!
So, stay tuned for more information and if you’re interested in reading more about differences between Tyrone and I, check out these papers from the Maruska lab:
Maruska, K.P.and R.D. Fernald. 2018. Astatotilapia burtoni: A model system for analyzing the neurobiology of behavior. ACS Chemical Neuroscience. 9: 1951-1962. link
Maruska, K.P. 2015. Social transitions cause rapid behavioral and neuroendocrine changes. Integr Comp Biol. 55: 294-306. link
Maruska, K.P. 2014. Social regulation of reproduction in male cichlid fishes. Gen Comp Endocrinol. 207: 2-12. link
Maruska, K.P. and R.D. Fernald. 2014. Social regulation of gene expression in the African cichlid fish, Astatotilapia burtoni. pp. 52-78. Oxford Handbook of Molecular Psychology (Canli, T., ed). Oxford University Press. link