Meet the First Gene-Edited Reptile: An Albino Lizard
By Malavika Vyawahare
Think of a reptile that's been genetically mutated, and Godzilla springs to mind. Or maybe ninja turtles.
But the real thing is here, and it's neither hell-bent on destroying Tokyo nor eating pizza in the sewers. Instead, it's a pale, finger-sized lizard — the world's first gene-edited reptile, researchers at the University of Georgia reported this week.
In a paper published in the journal Cell Reports, Douglas B. Menke and his colleagues described how they made an albino version of the brown anole (Anolis sagrei), a species of lizard native to Cuba and the Bahamas.
"Instead of performing gene-editing on fertilized eggs or single-cell embryos, we performed gene-editing on unfertilized eggs while they are still physically attached to the ovary of adult female lizards," said Menke, a geneticist and developmental biologist.
The first genetically modified animal was a transgenic mouse, created in 1974. But it was only seven years later that researchers could edit genes that were passed on to future generations. In the case of the albino lizard, the changes are inheritable.
Though gene editing has been around for decades and the advent of CRISPR technology makes it easier and is more efficient to carry out, doing so in reptilian zygotes is particularly challenging. Researchers consider it best to make an edit when the embryo is newly formed. For animals that reproduce sexually, the target is usually a single cell at this stage.
In reptiles, it's difficult to pin down when fertilization actually happens, in large part due to internal fertilization and sperm storage, where females can store sperm for extended periods. In A. sagrei lizards, the females can store sperm for more than two months.
The Anolis genus, which includes more than 400 species, is native to Central and South America and the Caribbean islands. Brown anole lizards are widely distributed beyond their native Cuba and Bahamas because they're a highly invasive species. The lizards used in the experiment were caught from the wild in Orlando, Florida.
The scientists performed surgery to insert gene-editing reagents into 146 unfertilized eggs of 21 adult female lizards. The females were then mated with adult males. A fraction of the resulting offspring carried the mutation, which manifested as albinism. The edit is unlikely to be lethal to the animals.
The downside of manipulating the egg and not the embryo is that it doesn't host the paternal DNA, reducing the chances that the edit will manifest in the offspring. For their study, the authors had to wait for three months for the lizard eggs to hatch to verify whether their editing method had induced the desired mutation.
Only about 6 to 9 percent of the eggs in which the edit was introduced produced mutant lizards. This is low when compared to other methods that report efficiencies of 80 percent or more. However, being able to produce the change in those few individuals is itself a breakthrough. The authors say the efficiency can be boosted by targeting larger eggs (more than 0.75 mm in diameter), which had the highest success rate in this experiment.
Editing genes is one of the key ways to deduce what role they play and which traits they're associated with. The University of Georgia researchers are already exploring different gene functions in Anolis lizards and say they hope this will aid in the study of genetic defects in humans. For example, people with albinism are also likely to have poor eyesight due to defects in a part of the eye called the fovea. Mice that are widely used for genetic studies don't have a fovea and so studying in albinism in mice may not shed light on the link between albinism and impaired vision.
Gene editing can also be used to curb invasive species populations. Its most widely known application is to control mosquito populations, but with advances in gene editing this could be extended to invasive reptiles as well.
"There are over 10,000 described species of reptile, and the genome of each species contains around 25,000 protein-coding genes. There is a whole universe of unstudied biology in these animals," Menke said. "We hope that other research groups will adapt our gene-editing method to investigate gene function in additional reptile species."
Reposted with permission from our media associate Mongabay.
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By Sara Lindberg
Whether you've hit a workout plateau or you're just ready to turn things up a notch, adding more strenuous exercise — also known as high-intensity exercise — to your overall fitness routine is one way to increase your calorie burn, improve your heart health, and boost your metabolism.
However, to do it safely and effectively, there are some guidelines you should follow. Keep reading to learn more about the benefits of vigorous exercise and how to safely dial up the intensity of your workouts.
What Is Considered Strenuous Exercise?<p>When it comes to exercise, the intensity of how hard you work out is just as important as the duration of your exercise session. In general, exercise intensity is divided into three categories:</p><ul><li>low</li><li>moderate</li><li>vigorous or strenuous</li></ul><p>For an activity to be vigorous, you need to work at 70 to 85 percent of your maximum heart rate, according to the<a href="https://www.heart.org/en/healthy-living/fitness/fitness-basics/target-heart-rates" target="_blank"> American Heart Association</a>. Examples of vigorous exercise include:</p><ul><li>running</li><li>cycling at 10 mph or faster</li><li>walking briskly uphill with a heavy backpack</li><li>jumping rope</li></ul><p>Low to moderate exercise is easier to sustain for longer periods since you work below 70 percent of your maximum heart rate and, sometimes, well below that level.</p><p>To reap health benefits, the <a href="https://www.hhs.gov/fitness/be-active/physical-activity-guidelines-for-americans/index.html" target="_blank">Physical Activity Guidelines for Americans</a> recommends that people age 18 and older get one of the following:</p><ul><li><strong>150 minutes</strong> of moderate-intensity aerobic activity per week</li><li><strong>75 minutes</strong> of vigorous aerobic activity per week</li><li><strong>combination of both types</strong> of activity spread throughout the week</li></ul>
Strenuous Exercise Vs. Moderate Exercise<p>Increasing your exercise intensity is fairly simple to do. You can still participate in your favorite activities — just at a more vigorous pace.</p><p>One of the benefits of more strenuous exercise is that you can reap the same rewards as moderate-intensity exercise but in less time. So, if time is of the essence, doing a more strenuous 20-minute workout can be just as beneficial as doing a slower 40-minute workout session.</p><p>Here are some examples of <a href="https://www.cdc.gov/nccdphp/dnpa/physical/pdf/pa_intensity_table_2_1.pdf" target="_blank">strenuous vs. moderate exercise<span></span></a>.</p><table><tbody><tr><th>Moderate intensity</th><th>Strenuous intensity</th></tr><tr><td>bicycling at less than 10 mph</td><td>bicycling at more than 10 mph</td></tr><tr><td>walking briskly</td><td>running, or hiking uphill at a steady pace</td></tr><tr><td>jog-walk intervals</td><td>water jogging/running</td></tr><tr><td>shooting baskets in basketball</td><td>playing a basketball game</td></tr><tr><td>playing doubles tennis</td><td>playing singles tennis</td></tr><tr><td>raking leaves or mowing the lawn</td><td>shoveling more than 10 lbs. per minute, digging ditches</td></tr><tr><td>walking stairs</td><td>running stairs</td></tr></tbody></table>
Benefits of Vigorous Exercise<p>Besides being more efficient, turning up the heat on your fitness sessions can benefit your health in a variety of ways. Let's take a closer look at some of the evidence-based benefits of a higher intensity workout.</p><ul><li><strong>Higher calorie burn.</strong> According to the <a href="https://www.acefitness.org/education-and-resources/professional/expert-articles/5008/7-things-to-know-about-excess-post-exercise-oxygen-consumption-epoc/?utm_source=Rakuten&utm_medium=10&ranMID=42334&ranEAID=TnL5HPStwNw&ranSiteID=TnL5HPStwNw-hYlKnAcfzfixAUsvnO6Ubw" target="_blank">American Council on Exercise</a>, working out at a higher intensity requires more oxygen, which burns more calories. It also contributes to excess post-exercise oxygen consumption (EPOC) or the "afterburn effect" that allows you to continue burning calories even after you finish working out. This means your metabolism will stay elevated for longer after a vigorous exercise session.</li><li><strong>More weight loss.</strong> A <a href="https://www.healthline.com/health-news/interval-workouts-will-help-you-lose-weight-more-quickly" target="_blank">higher calorie burn</a> and an elevated metabolism will help you lose weight more quickly than doing low- or moderate-intensity exercise.</li><li><strong>Improved heart health.</strong> According to a <a href="https://www.ncbi.nlm.nih.gov/pubmed/16377300" target="_blank">2012 study</a>, high- and moderate-intensity exercise appears to offer low chance of cardiovascular events, even in those with heart disease. Cardiovascular benefits may include improvements in:<ul><li><a href="https://www.healthline.com/health/diastole-vs-systole" target="_blank">diastolic blood pressure</a></li><li><a href="https://www.healthline.com/nutrition/15-ways-to-lower-blood-sugar#TOC_TITLE_HDR_1" target="_blank">blood sugar control</a></li><li>aerobic capacity</li></ul></li><li><strong>Improved mood.</strong> High-intensity exercise may also boost your mood. According to a large <a href="https://www.jstage.jst.go.jp/article/jpts/27/4/27_jpts-2014-736/_article" target="_blank">2015 study</a> that analyzed the data of more than 12,000 participants, researchers found a significant link between strenuous exercise and fewer depressive symptoms.</li><li><strong>Lower risk of mortality.</strong> According to a 2015 <a href="https://www.ncbi.nlm.nih.gov/pubmed/25844882" target="_blank">study</a>, researchers found that vigorous activity may be key to avoiding an early death. The study, which followed 204,542 people for more than 6 years, reported a 9 to 13 percent decrease in mortality for those who increased the intensity of their exercise sessions.</li></ul>
How to Measure Exercise Intensity<p>So, how do you know for sure that you're exercising at a strenuous level? Let's look at three ways to measure the intensity of your physical activity.</p><h3>1. Your heart rate</h3><p>Monitoring your heart rate is one of the most reliable methods for measuring exercise intensity. Exercising at 70 to 85 percent of your maximum heart rate qualifies as vigorous exercise intensity.</p><blockquote><strong><strong>WHAT IS YOUR MAXIMUM HEART RATE?</strong></strong>Your maximum heart rate is the fastest your heart can safely beat. To find out what your maximum heart rate is you need to subtract your age from 220. For example, for a 40-year-old person: <ul><li>220 bpm (beats per minute) minus age</li><li>220 – 40 = 180 bpm</li></ul>To work out at a vigorous pace, you'll want to exercise within 70 to 85 percent of your maximum heart rate. For example: <ul><li>180 x 0.70 (70 percent) = 126</li><li>180 x 0.85 (85 percent) = 153</li></ul>For a 40-year-old person, a vigorous training range is 126 to 153 bpm.<br></blockquote><p>You can check your heart rate while you're working out by wearing a heart rate monitor or <a href="https://www.healthline.com/health/how-to-check-heart-rate" target="_blank">taking your pulse</a>.</p>
How to Add Vigorous Activity to Your Workout<p>Adding strenuous activity to your weekly workout routine requires some careful planning. Fortunately, many of the activities that you do at a moderate level can easily be performed at a higher intensity.</p><p>One way of incorporating vigorous aerobic activity into your routine is to do a <a href="https://www.healthline.com/nutrition/benefits-of-hiit" target="_blank">high-intensity interval training (HIIT)</a> workout. This type of workout combines short bursts of intense activity — typically performed at 80 to 95 percent of your maximum heart rate — with recovery periods at 40 to 50 percent maximum heart rate.</p><p>To sustain this level of training, consider following a 2:1 work to rest ratio. For example, a <a href="https://www.healthline.com/health/treadmill-weight-loss#hiit" target="_blank">treadmill workout </a>or outdoor running session could include:</p><ul><li>running at 9 to 10 mph for 30 seconds</li><li>followed by walking at 3 to 4 mph for 60 seconds</li><li>alternating this work-to-rest ratio for 20 to 30 minutes</li></ul><p>Playing a fast-paced sport like soccer, basketball, or racquetball is another effective way to add strenuous activity to your fitness routine. Participating in <a href="https://www.healthline.com/health/benefits-of-a-spin-class" target="_blank">cycling classes</a> or swimming laps are other ways to build more strenuous exercise into your workouts.</p>
Safety Tips<p>Before you turn up the intensity on your workouts, it's important to keep the following safety tips in mind.</p><h3>Check with your doctor</h3><p>If you have a health condition or you haven't been active in a while, make sure you talk to your doctor before you start a high-intensity exercise routine. Your doctor can advise you on a safe level of exercise or how to become more active in the safest way possible.</p><h3>Build up the intensity slowly</h3><p>Going from low- or moderate-intensity workouts to vigorous exercise requires time and patience. While you may be ready to jump in with both feet, the safest way to add more vigorous exercise is to do it in bite-size increments. Pushing yourself too quickly can result in injuries and burnout.</p><p>For example:</p><ul><li><strong>Week 1:</strong> Swap out one moderate-paced cardio session for a HIIT workout.</li><li><strong>Week 2:</strong> Swap one moderate-paced session with a HIIT workout, and also add a circuit strength training session to your weekly routine.</li><li><strong>Week 3 and 4: </strong>Repeat weeks 1 and 2 before you start adding more high-intensity exercise to your weekly routine.</li></ul><p>It's also a good idea to space out your vigorous workouts throughout the week. Try not to do two strenuous sessions back-to-back.</p><h3>Don't forget the recovery time</h3><p>Your body requires more time to recover from a vigorous workout compared to a low- or moderate-intensity session.</p><p>To help your body recover, make sure to always include a cooldown and <a href="https://www.healthline.com/health/exercise-fitness/static-stretching" target="_blank">stretch routine</a> after strenuous physical activity.</p><h3>Stay hydrated</h3><p><a href="https://www.healthline.com/nutrition/7-health-benefits-of-water" target="_blank">Staying hydrated</a> is especially important when you're exercising hard. Not drinking enough fluids can affect the quality of your workout and make you feel tired, lethargic, or dizzy. It may even lead to <a href="https://www.healthline.com/health/dehydration-headache" target="_blank">headaches</a> and <a href="https://www.healthline.com/health/pain-relief/how-to-stop-leg-muscle-cramps" target="_blank">cramps</a>.</p>
The Bottom Line<p>Turning up the intensity of your workout sessions can be an effective way of boosting your overall health and fitness. It's also an easy way to save time when trying to fit a workout into your day.</p><p>To play it safe, always start slow and pay attention to how your body feels.</p><p>While vigorous exercise offers many health benefits, it's not appropriate for everyone. If you have a health condition or you haven't been active in a while, make sure to talk with your doctor before working out at a more strenuous level.</p>
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By Jeffrey Miller
In January 2015, food sales at restaurants overtook those at grocery stores for the first time. Most thought this marked a permanent shift in the American meal.
Solving the Age-Old Problem of Spoiled Cheese<p>People have eaten pasta and cheese together for hundreds of years. Clifford Wright, the doyen of Mediterranean food history, says <a href="http://www.cliffordawright.com/caw/food/entries/display.php/topic_id/16/id/105/" target="_blank">the first written recipe</a> for macaroni and cheese was created in the court of the king of Naples in the 13th century, while <a href="https://food52.com/blog/9916-the-history-of-macaroni-and-cheese" target="_blank">the first reference</a> in an English language cookbook likely appeared in Elizabeth Raffald's 1769 book "The Experienced English Housekeeper."</p><p><span></span>An internet search for macaroni and cheese recipes will turn up over 5 million hits, but many still prefer to get theirs in a box – the kind with pasta that comes in shapes ranging from shells to Pokemon characters, accompanied by a packet of powdered cheese sauce.</p><p>Boxed macaroni and cheese was one outcome of the quest for ways to keep cheese longer. Some cheese gets better as it ages – a well-aged cheddar is one of life's delights – but once most cheeses hit their prime, <a href="https://www.dairyfoods.com/articles/91548-how-to-maximize-cheese-shelf-life" target="_blank">they tend to quickly go bad</a>. Before household refrigeration became common, many retailers wouldn't even stock cheese in the summer because it spoiled so quickly.</p><p>Processed cheese solved this age-old problem.</p>
When Natural Was Nasty<p>Today, food that's simple, pure and natural is <a href="https://theconversation.com/how-was-french-cuisine-toppled-as-the-king-of-fine-dining-66667" target="_blank">all the craze</a>, while <a href="https://apnews.com/c06a1200807c4b82a03452d08d480692" target="_blank">disdain for processed foods</a> is practically a credo among sophisticated consumers.</p><p>But when Kraft's different forms of processed cheese came out, they found widespread acceptance despite their strange textures. The fact that it wasn't natural didn't seem to bother consumers at all. In fact, as international food historian Rachel Laudan <a href="https://online.ucpress.edu/gastronomica/article/1/1/36/93394/A-Plea-for-Culinary-Modernism-Why-We-Should-Love" target="_blank">has noted</a>, back then, "natural was something quite nasty." She describes fresh milk as warm and "unmistakably a bodily secretion." Throughout the history of cookery, most recipes aimed to transform an unappetizing raw product into something delightful and delectable.</p><p>So for most consumers, processed foods were a godsend. They kept well, tended to be easily digestible and, most importantly, they tasted good. Many of them could be easily prepared, freeing women from spending entire days cooking and giving them more time to pursue professions and avocations.</p><p>In some ways, processed foods were also healthier. They could be fortified with vitamins and minerals, and, in an era before everyone had access to mechanical refrigeration, the fact that they kept well meant consumers were less likely to contract diseases from spoiled, rotten foods. Pasteurization of dairy products virtually <a href="https://www.the-scientist.com/foundations/rethinking-raw-milk--1918-65126" target="_blank">eliminated diseases like undulant fever</a>, while foods processed and canned in large factories were less likely to harbor food-borne illnesses that could crop up due to faulty or improperly sanitized equipment used by home canners.</p>
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Some fires won't die.
They survive underground during the winter and then reemerge the following spring, as documented in places like Alaska. They're called "overwintering," "holdover," or "zombie" fires, and they may have now awoken in the Arctic Circle — a fast-warming region that experienced unprecedented fires in 2019. The European Union's Copernicus Atmosphere Monitoring Service is now watching these fires, via satellite.