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How biological differences between men and women alter immune responses – and affect women’s health

<p><a href="">Helen McGettrick</a>, <em><a href="">University of Birmingham</a></em> and <a href="">Asif Iqbal</a>, <em><a href="">University of Birmingham</a></em></p> <p>Most people will have heard the term “man flu”, which refers to men’s perceived tendency to exaggerate the severity of a cold or a similar minor ailment.</p> <p>What most people may not know is that, generally speaking, women mount stronger <a href="">immune responses</a> to infections than men. Men are <a href="">more susceptible</a> to infections from, for example, HIV, hepatitis B, and <em>Plasmodium falciparum</em> (the parasite responsible for malaria).</p> <p>They can also have more severe symptoms, with evidence showing they’re more likely to be <a href="">admitted to hospital</a> when infected with hepatitis B, tuberculosis, and <em>Campylobacter jejuni</em> (a bacteria that causes gastroenteritis), among others.</p> <p>While this may be positive for women in some respects, it also means women are at <a href="">greater risk</a> of developing chronic diseases driven by the immune system, known as immune-mediated inflammatory diseases.</p> <p>Here we will explore how biological factors influence immune differences between the sexes and how this affects women’s health. While we acknowledge that both sex and gender may affect immune responses, this article will focus on biological sex rather than gender.</p> <h2>Battle of the sexes</h2> <p>There are differences <a href="">between the sexes</a> at every stage of the immune response, from the number of immune cells, to their degree of activation (how ready they are to respond to a challenge), and beyond.</p> <p>However, the story is more complicated than that. Our immune system evolves throughout our lives, learning from past experiences, but also responding to the physiological challenges of getting older. As a result, <a href="">sex differences</a> in the immune system can be seen from birth through puberty into adulthood and <a href="">old age</a>.</p> <p>Why do these differences occur? The first part of answering this question involves the X chromosome. Females have two X chromosomes, while males have one X and one Y chromosome. The <a href="">X chromosome</a> contains the largest number of immune-related genes.</p> <p>The X chromosome also has <a href="">around 118 genes</a> from a gene family that are able to stop the expression of other genes, or change how proteins are made, including those required for immunity. These gene-protein regulators are known as microRNA, and there are only <a href="">two microRNA genes</a> on the Y chromosome.</p> <p>The X chromosome has <a href="">more genes overall</a> (around 900) than the Y chromosome (around 55), so female cells have evolved to switch off one of their X chromosomes. This is not like turning off a light switch, but more like using a dimmer.</p> <p>Around <a href="">15-25% of genes</a> on the silenced X chromosome are expressed at any given moment in any given cell. This means female cells can often express more immune-related genes and gene-protein regulators than males. This generally means a faster clearance of pathogens in females than males.</p> <p>Second, men and women have <a href="">varying levels</a> of different sex hormones. Progesterone and testosterone are broadly considered to limit immune responses. While both hormones are produced by males and females, progesterone is found at higher concentrations in non-menopausal women than men, and testosterone is much higher in men than women.</p> <p>The role of <a href="">oestrogen</a>, one of the main female sex hormones, is more complicated. Although generally oestrogen <a href="">enhances immune responses</a>, its levels vary during the menstrual cycle, are high in pregnancy and low after menopause.</p> <p>Due in part to these genetic and hormonal factors, pregnancy and the years following are associated with heightened immune responses to external challenges such as infection.</p> <p>This has been regarded as an <a href="">evolutionary feature</a>, protecting women and their unborn children during pregnancy and enhancing the mother’s survival throughout the child-rearing years, ultimately ensuring the survival of the population. We also see this pattern in <a href="">other species</a> including insects, lizards, birds and mammals.</p> <h2>What does this all mean?</h2> <p>With women’s heightened immune responses to infections comes an increased risk of certain diseases and prolonged immune responses after infections.</p> <p>An <a href="">estimated 75-80%</a> of all immune-mediated inflammatory diseases <a href="">occur in females</a>. Diseases more common in women include multiple sclerosis, <a href="">rheumatoid arthritis</a>, lupus, Sjogren’s syndrome, and <a href="">thyroid disorders</a> such as Graves disease.</p> <p>In these diseases, the immune system is continuously fighting against what it sees as a foreign agent. However, often this perceived threat is not a foreign agent, but cells or tissues from the host. This leads to tissue damage, pain and immobility.</p> <p>Women are also prone to chronic inflammation following infection. For example, after infections with <a href="">Epstein Barr virus</a> or <a href="">Lyme disease</a>, they may go on to develop <a href="">chronic fatigue syndrome</a>, another condition that affects more women than men.</p> <p>This is one possible explanation for the heightened risk among <a href="">pre-menopausal women</a> of developing long COVID following infection with SARS-CoV-2, the virus that causes COVID.</p> <p>Research has also revealed the presence of auto-antibodies (antibodies that attack the host) in patients with long COVID, suggesting it might be an <a href="">autoimmune disease</a>. As women are more susceptible to autoimmune conditions, this could potentially explain the sex bias seen.</p> <p>However, the exact causes of long COVID, and the reason women may be at greater risk, are yet to be defined.</p> <p>This paints a bleak picture, but it’s not all bad news. Women typically mount <a href="">better vaccine responses</a> to several common infections (for example, influenza, measles, mumps, rubella, hepatitis A and B), producing higher antibody levels than men.</p> <p>One study showed that women vaccinated with half a dose of flu vaccine produced the same amount of antibodies compared to men vaccinated with <a href="">a full dose</a>.</p> <p>However, these responses <a href="">decline as women age</a>, and particularly <a href="">after menopause</a>.</p> <p>All of this shows it’s vital to consider sex when designing studies examining the immune system and treating patients with immune-related diseases.<!-- Below is The Conversation's page counter tag. Please DO NOT REMOVE. --><img style="border: none !important; box-shadow: none !important; margin: 0 !important; max-height: 1px !important; max-width: 1px !important; min-height: 1px !important; min-width: 1px !important; opacity: 0 !important; outline: none !important; padding: 0 !important;" src="" alt="The Conversation" width="1" height="1" /><!-- End of code. If you don't see any code above, please get new code from the Advanced tab after you click the republish button. The page counter does not collect any personal data. More info: --></p> <p><em><a href="">Helen McGettrick</a>, Reader in Inflammation and Vascular Biology, <a href="">University of Birmingham</a> and <a href="">Asif Iqbal</a>, Associate Professor in Inflammation Biology, <a href="">University of Birmingham</a></em></p> <p><em>Image credits: Getty Images</em></p> <p><em>This article is republished from <a href="">The Conversation</a> under a Creative Commons license. Read the <a href="">original article</a>.</em></p>


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Another sexist biological hypothesis debunked

<p>For over a century, the idea of ‘<a rel="noopener" href="" target="_blank">greater male variability</a>’ has been used by some biologists to explain why there are more male CEOs and political leaders than female, among other things. But a <a rel="noreferrer noopener" href="" target="_blank">meta-analysis</a> in <em>Biological Reviews</em> has challenged this idea, finding that, in animals, greater male variability doesn’t seem to exist at all.</p> <p>“It’s easier to think of variability as like a spectrum or range,” explains lead author Lauren Harrison, a PhD student in biology at the Australian National University.</p> <p>“If you think about personalities, for example, we all fall somewhere along a spectrum that ranges from very introverted at one end, to very extroverted at the other. And so, variability is a measure of how spread out our values are altogether.”</p> <p>In 1871, Charles Darwin suggested that, in general, male animals had more variability in their traits than female animals, possibly because of sexual selection.</p> <p>The idea was almost immediately adopted by some scientists and non-scientists to explain that, because males were more variable than females, there must therefore be more ‘exceptional’ men, justifying their superior role in society. The concept has never been without its challengers, particularly among female scientists, but it’s remained pervasive.</p> <p>Harrison, along with colleagues at ANU, went looking for evidence of this hypothesis. She examined over 10,000 published papers from database searches on the topic, eventually narrowing the field down to 204 relevant studies on animal behaviour, covering 220 species (but not humans).</p> <p>Simply finding these 204 relevant studies was an effort. “I think it took me the better part of three months,” says Harrison. “And that was all that I was doing.”</p> <p>Once these papers were collected, the researchers used their data to examine five key behavioural traits in animals: boldness, aggressiveness, exploration, sociability and activity.</p> <div class="newsletter-box"> <div id="wpcf7-f6-p178706-o1" class="wpcf7"> <p style="display: none !important;"> </p> <!-- Chimpmail extension by Renzo Johnson --></div> </div> <p>And their results? “We found no evidence of greater male variability,” says Harrison.</p> <p>“So really, is it as general as we think? No, it’s not. So maybe it is easier to disprove than we think.”</p> <p>While their research didn’t include humans, Harrison says they’d be surprised to find the results differed there.</p> <p>“Our species covered things from dolphins to little beetles and everything in between. Fish, reptiles, birds, and even primates.</p> <p>“Finding no greater male variability across such a broad number of species shows that, well, in animals, we don’t really see this trend. So if we do see a trend in humans, maybe we need to ask ourselves why we’re so different – what would be causing these differences between men and women?”</p> <p>Current research on human variability hasn’t yielded heaps of evidence for this trend.</p> <p>“It’s all quite conflicting,” says Harrison.</p> <p>“Sometimes they find greater female variability [in humans], greater male variability or no differences. So I wouldn’t really say it’s a very well proven hypothesis at all.”</p> <p>She adds that this research is another indicator that social differences between men and women are more likely to have <a rel="noreferrer noopener" href="" target="_blank">cultural</a>, than biological, origins.</p> <p>“Instead of using biology to explain why there are more male CEOs or professors, we have to ask what role culture and upbringing play in pushing men and women down different pathways.”</p> <!-- Start of tracking content syndication. Please do not remove this section as it allows us to keep track of republished articles --> <p><img id="cosmos-post-tracker" style="opacity: 0; height: 1px!important; width: 1px!important; border: 0!important; position: absolute!important; z-index: -1!important;" src=";title=Greater+Male+Variability+hypothesis+challenged" alt="" width="1" height="1" /></p> <!-- End of tracking content syndication --> <div id="contributors"> <p><em><a rel="noopener" href="" target="_blank">This article</a> was originally published on <a rel="noopener" href="" target="_blank">Cosmos Magazine</a> and was written by <a rel="noopener" href="" target="_blank">Ellen Phiddian</a>. Ellen Phiddian is a science journalist at Cosmos. She has a BSc (Honours) in chemistry and science communication, and an MSc in science communication, both from the Australian National University.</em></p> <p><em>Image: Getty Images</em></p> </div>


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Heroes, villains ... biology: 3 reasons comic books are great science teachers

<p>People may think of comics and science as worlds apart, but they have been cross-pollinating each other in more than ways than one.</p> <p>Many classic comic book characters are inspired by biology such as Spider-Man, Ant-Man and Poison Ivy. And they can act as educational tools to gain some fun facts about the natural world.</p> <p>Some superheroes have scientific careers alongside their alter egos. For example, Marvel’s <a href="">The Unstoppable Wasp</a> is a teenage scientist. And DC Comics’ super-villain <a href="">Poison Ivy</a> is a botanist who saved honey bees from colony collapse.</p> <p>Superheroes have also crept into the world of taxonomy, with animals being named after famous comic book characters. These include a <a href="">robber fly</a> named after the Marvel character Deadpool (whose mask looks like the markings on the fly’s back) and a <a href="">fish</a> after Marvel hero Black Panther.</p> <p>I am a PhD student researching bee behaviour and I have spent most of my university life working at a comic book store. Here’s how superheroes could be used to make biology, and other types of science, more intriguing to school students.</p> <h2>1. They’re engaging</h2> <p>Reading has a range of benefits, <a href="">from improved vocabulary</a>, <a href="">comprehension and mathematics skills, to increased empathy and creativity</a>.</p> <p>While it’s hard to directly prove the advantages of comics over other forms of reading, they <a href=",engaging%20for%20a%20wider%20audience.">can be engaging</a>, easy to understand learning tools.</p> <p>Comics <a href="">have similar benefits</a> to classic textbooks in terms of understanding course content. But they can be more captivating.</p> <p>A study of 114 business students showed they <a href="">preferred</a> graphic novels over classic textbooks for learning course content.</p> <p>In another <a href="">study in the United States</a>, college biology students were given either a textbook or a graphic novel — <a href="">Optical Allusions</a> by scientist Jay Hosler, that follows a character discovering the science of vision — as supplementary reading for their biology course.</p> <p>Both groups of students showed similar increases in course knowledge, but students who were given the graphic novel showed an increased interest in the course.</p> <p><a href=";q=45&amp;auto=format&amp;w=1000&amp;fit=clip"><img src=";q=45&amp;auto=format&amp;w=237&amp;fit=clip" alt="Front cover of the Unstoppable Wasp." /></a> <span class="caption">The Unstoppable Wasp is a teenage scientist.</span> <span class="attribution"><a href="" class="source">Marvel</a></span></p> <p>So, comics can be used to engage students, <a href="">especially those who aren’t very interested in science</a>.</p> <p>Educational comics such as the <a href="">Science Comics series</a>, Jay Hosler’s <a href="">The Way of the Hive</a> and Abby Howard’s <a href="">Earth Before Us</a> series frequently have a narrative structure with a story consisting of a beginning, middle and resolution.</p> <p>Students often find information inside storytelling easier to <a href="">comprehend</a> than when it’s provided matter-of-factly, such as in textbooks. As readers follow a story, they can use key information they have learnt along the way to understand and interpret the resolution.</p> <h2>2. They teach important concepts</h2> <p>In science-related comic books, as the story unfolds, scientific concepts are often sprinkled in along the way. For example, <a href="">Science Comics: Bats</a>, follows a bat going through a rehabilitation clinic while suffering from a broken wing. The reader learns about different bat species and their ecology on this journey.</p> <p>Comics also have the advantage of <a href="">permanance</a>, meaning students can read, revisit and understand panels at their own pace.</p> <p>Many science comics, including Optical Allusions, are written by scientists, allowing for reliable facts.</p> <div data-react-class="Tweet" data-react-props="{&quot;tweetId&quot;:&quot;1367457735734751234&quot;}"></div> <p>Using storytelling can also <a href="">humanise scientists</a> by creating relatable characters throughout comics. Some graphic novels showcase <a href="">scientific</a> careers and can be a great tool for removing stereotypes of the lab coat wearing scientist. For example, Jim Ottaviani and Maris Wick’s graphic novels <a href="">Primates</a> and <a href="">Astronauts: Women on the Final Frontier</a> showcase female scientists in labs, the field and even space.</p> <p>The Marvel series’ Unstoppable Wasp also includes interviews with female scientists at the end of each issue.</p> <h2>3. They can give a visual insight into strange worlds</h2> <p>Imagery combined with an easy to follow narrative structure can also give a look into worlds that may otherwise be hard to visualise. For example, <a href="">Science Comics: Plagues</a>, and the Manga series, <a href="">Cells at Work!</a>, are told from the point of view of microbes and cells in the body.</p> <p>Imagery can also show life cycles of animals that are potentially dangerous, or difficult to encounter, such as a honeybee colony, which was visualised through <a href="">Clan Apis</a>.</p> <p><iframe width="440" height="260" src=";start=0" frameborder="0" allowfullscreen=""></iframe></p> <p><em>The author would like to acknowledge neuroscientist and cartoonist <a href="">Matteo Farinella</a>, whose advice helped shape this article.</em><!-- Below is The Conversation's page counter tag. Please DO NOT REMOVE. --><img style="border: none !important; box-shadow: none !important; margin: 0 !important; max-height: 1px !important; max-width: 1px !important; min-height: 1px !important; min-width: 1px !important; opacity: 0 !important; outline: none !important; padding: 0 !important; text-shadow: none !important;" src="" alt="The Conversation" width="1" height="1" /><!-- End of code. If you don't see any code above, please get new code from the Advanced tab after you click the republish button. The page counter does not collect any personal data. More info: --></p> <p><span><a href="">Caitlyn Forster</a>, PhD Candidate, School of Life and Environmental Sciences, <em><a href="">University of Sydney</a></em></span></p> <p>This article is republished from <a href="">The Conversation</a> under a Creative Commons license. Read the <a href="">original article</a>.</p>


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The biology of coffee

<p>You’re reading this with a cup of coffee in your hand, aren’t you? Coffee is the most popular drink <a href="">in many parts of the world</a>. Americans drink more coffee than soda, juice and tea — <a href="">combined</a>.</p> <p>How popular is coffee? When news first broke that Prince Harry and Meghan were considering Canada as their new home, Canadian coffee giant Tim Hortons offered free coffee for life as an extra enticement.</p> <p>Given coffee’s popularity, it’s surprising how much confusion surrounds how this hot, dark, nectar of the gods affects our biology.</p> <p><strong>Coffee’s ingredients</strong></p> <p>The main biologically active ingredients in coffee are caffeine (a stimulant) and a suite of antioxidants. What do we know about how caffeine and antioxidants affect our bodies? The fundamentals are pretty simple, but the devil is in the details and the speculation around how coffee could either help or harm us runs a bit wild.</p> <p>The stimulant properties of caffeine mean that you can count on a cup of coffee to wake you up. In fact, coffee, or at least the caffeine it contains, is the most <a href="">commonly used psychoactive drug in the world</a>. It seems to work as a stimulant, at least in part, by blocking adenosine, which promotes sleep, from binding to its receptor.</p> <p>Caffeine and adenosine have similar ring structures. Caffeine acts as a molecular mimic, filling and blocking the adenosine receptor, preventing the body’s natural ability to be able a rest when it’s tired.</p> <p>This blocking is also the reason why too much coffee can leave you feeling jittery or sleepless. You can only postpone fatigue for so long before the body’s regulatory systems begin to fail, leading to simple things like the jitters, but also more serious effects like <a href="">anxiety or insomnia</a>. Complications may be common; a possible link between coffee drinking and insomnia was identified <a href="">more than 100 years ago</a>.</p> <p style="text-align: center;"><iframe width="440" height="260" src=";start=0" frameborder="0" allowfullscreen=""></iframe></p> <p style="text-align: center;"><span class="caption">The National Film Board of Canada produced a documentary on the cultural history of coffee called <em>Black Coffee: Part One, The Irresistible Bean</em></span></p> <p><strong>Unique responses</strong></p> <p>Different people respond to caffeine differently. At least some of this variation is from having <a href="">different forms of that adenosine receptor</a>, the molecule that caffeine binds to and blocks. There are <a href="">likely other sites of genetic variation as well</a>.</p> <p>There are individuals who don’t process caffeine and to whom drinks like coffee <a href="">could pose medical danger</a>. Even away from those extremes, however, there is variation in how we respond to that cup of coffee. And, like much of biology, that variation is a function of environment, our past coffee consumption, genetics and, honestly, just random chance.</p> <p>We may be interested in coffee because of the oh-so-joyous caffeine buzz, but that doesn’t mean that caffeine is the most biologically interesting aspect of a good cup of coffee.</p> <p>In one study using rats, caffeine triggered smooth muscle contraction, so it is possible that <a href="">caffeine directly promotes bowel activity</a>. Other studies, though, have shown that decaffeinated coffee can have as strong an effect on bowel activity as regular coffee, suggesting <a href="">a more complex mechanism involving some of the other molecules in coffee</a>.</p> <p><strong>Antioxidant benefits</strong></p> <p>What about <a href="">the antioxidants in coffee</a> and the buzz that surrounds them? Things actually start out pretty straightforward. Metabolic processes produce the energy necessary for life, but they also create waste, often in the form of oxidized molecules that can be harmful in themselves or in damaging other molecules.</p> <p>Antioxidants are a broad group of molecules that can scrub up dangerous waste; all organisms produce antioxidants as part of their metabolic balance. It is unclear if supplementing our diet with additional antioxidants can augment these natural defences, but that hasn’t stopped speculation.</p> <p>Antioxidants have been linked to almost everything, including <a href="">premature ejaculation</a>.</p> <p>Are any of the claims of positive effects substantiated? Surprisingly, the answer is again a resounding maybe.</p> <p><strong>Coffee and cancer</strong></p> <p>Coffee won’t cure cancer, but it may help to prevent it and possibly other diseases as well. Part of answering the question of coffee’s connection to cancer lies in asking another: what is cancer? At its simplest, cancer is uncontrolled cell growth, which is fundamentally about regulating when genes are, or are not, actively expressed.</p> <p>My research group studies <a href="">gene</a> <a href="">regulation</a> and I can tell you that even a good cup of coffee, or boost of caffeine, won’t cause genes that are turned off or on at the wrong time to suddenly start playing by the rules.</p> <p>The antioxidants in coffee may actually have <a href="">a cancer-fighting effect</a>. Remember that antioxidants fight cellular damage. One type of damage that <a href=";2-3">they may help reduce is mutations to DNA</a>, and cancer is caused by mutations that lead to the misregulation of genes.</p> <p>Studies have shown that <a href="">consuming coffee fights cancer in rats</a>. Other studies in humans have shown that <a href="">coffee consumption is associated with lower rates of some cancers</a>.</p> <p>Interestingly, coffee consumption has also been linked to reduced rates of other diseases as well. Higher coffee consumption is linked to <a href="">lower rates of Parkinson’s disease</a> and some other forms of dementia. Strikingly, at least one experimental study in mice and cell culture shows that <a href="">protection is a function of a combination of caffeine and antioxidants in coffee</a>.</p> <p>Higher coffee consumption has also been linked to <a href="">lower rates of Type 2 diabetes</a>. Complexity, combined effects and variation between individuals seems to be the theme across all the diseases.</p> <p>At the end of the day, where does all this leave us on the biology of coffee? Well, as I tell my students, it’s complicated. But as most reading this already know, coffee will definitely wake you up in the morning.<!-- End of code. If you don't see any code above, please get new code from the Advanced tab after you click the republish button. The page counter does not collect any personal data. More info: --></p> <p><span><a href=""><em>Thomas Merritt</em></a><em>, Professor and Canada Research Chair, Chemistry and Biochemistry, <a href="">Laurentian University</a></em></span></p> <p><em>This article is republished from <a href="">The Conversation</a> under a Creative Commons license. Read the <a href="">original article</a>.</em></p>

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Student’s 65-million-year-old extremely rare find

<p><span style="font-weight: 400;">A college student with a slight obsession with dinosaurs has made the dig of a lifetime. </span></p> <p><span style="font-weight: 400;">Harrison Duran, a biology student from Dakota was on a palaeontology dig in southwestern North Dakota in the United States, when he unearthed a partial Triceratops skull.</span></p> <p><span style="font-weight: 400;">Harrison paired up with an expert excavator Michael Kjelland and together they underwent a two-week search at Hell Creek Formation - a site known for dinosaur fossils. </span></p> <p><span style="font-weight: 400;">The duo were attempting to find plant fossils and on day four into their dig, were left shocked at their significant find. </span></p> <p><span style="font-weight: 400;">"I can't quite express my excitement in that moment when we uncovered the skull," Mr Duran told his </span><a href=""><span style="font-weight: 400;">college website UC Merced</span></a><span style="font-weight: 400;">, on Wednesday.</span></p> <p><span style="font-weight: 400;">23-year-old Harrison found the fossil himself - it was turned upside down with its left horn partially exposed, and surrounded by fossils. </span></p> <p><span style="font-weight: 400;">"I've been obsessed with dinosaurs since I was a kid, so it was a pretty big deal," Mr Duran said.</span></p> <p><span style="font-weight: 400;">They named the dinosaur found as Alice - after the owner of the land. </span></p> <p><span style="font-weight: 400;">“Alice was meticulously stabilised with glue, plastered up and removed from a location she called home for over 65 million years,” the </span><a href=""><span style="font-weight: 400;">Fossil Excavations website</span></a><span style="font-weight: 400;"> read.</span></p> <p><span style="font-weight: 400;">The duo will now spend the next few months researching the rare fossil and preparing Alice for public showings. </span></p> <p><span style="font-weight: 400;">"It's such a rare opportunity to showcase something like this, and I'd like to share it with the campus community," he said.</span></p> <p><span style="font-weight: 400;">Alice’s location will be kept top secret to protect potential further finds. </span></p> <p><span style="font-weight: 400;">"There have been people in the past who have stolen dinosaur bones," Professor Kjelland told </span><a href=""><span style="font-weight: 400;">CNN.</span></a></p>

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