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How do human eggs stay dormant and reproductively healthy for decades in the ovaries?

<p>Human eggs form before birth and can remain reproductively viable for up to 50 years before they are fertilised. But how can they remain dormant and healthy in the ovaries for so long?</p> <p>According to a new study published in Nature, the answer lies in their altered metabolic activity – skipping the use of a key protein and enzyme complex (respiratory complex I).</p> <p>To generate energy in their dormant state and avoid creating harmful molecules that can damage DNA and cause cell death, human eggs instead use alternative metabolic pathways never before seen in other animal cell types.</p> <p>“Humans are born with all the supply of egg cells they have in life. As humans are also the longest-lived terrestrial mammal, egg cells have to maintain pristine conditions while avoiding decades of wear-and-tear,” explains lead author Aida Rodriguez-Nuevo, a postdoctoral researcher at the Centre for Genomic Regulation (CRG), Spain.</p> <p>“We show this problem is solved by skipping a fundamental metabolic reaction that is also the main source of damage for the cell. As a long-term maintenance strategy, it’s like putting batteries on standby mode,” she adds.</p> <p>“This represents a brand new paradigm never before seen in animal cells.”</p> <h2>Altered metabolism in oocytes</h2> <p>Human eggs first form in the ovaries during foetal development. During the early stages of maturation, immature egg cells (known as oocytes) are put into cellular arrest and can remain dormant for decades.</p> <p>During this period, the oocyte’s mitochondria – kind of like the batteries of the cell – still generate just enough energy to fulfill the cell’s needs.</p> <p>To investigate how they do this, researchers used a combination of live imaging and proteomic (large-scale study of proteins) and biochemistry techniques to investigate this energy generation in human and Xenopus (aquatic frog) oocytes.</p> <p>Interestingly, they found that the oocytes do not use a fundamental protein, known as complex I, that initiates the reactions that generate energy in the mitochondria of most other cells.</p> <p>In fact, complex I is virtually absent in oocytes.</p> <p>This allows oocytes to avoid creating molecules known as reactive oxygen species (ROS) – molecules containing oxygen that readily react with other chemicals. ROS are normal by-products of cellular metabolism but are harmful when they accumulate, damaging the normal function of DNA, proteins, and other cellular components, and eventually causing cell death.</p> <p>They are also associated with lower rates of fertilisation and embryo survival.</p> <p>Live imaging showed that neither Xenopus nor human early oocytes showed any detectable ROS signal.</p> <h2>Implications for preserving ovarian reserves</h2> <p>According to the authors of the study, this finding explains why some individuals with mitochondrial conditions linked to complex I don’t experience reduced fertility, compared to those with conditions affecting other mitochondrial respiratory complexes.</p> <p>This finding could also lead to new strategies to help preserve the human egg cell reserves of patients undergoing cancer treatment.</p> <p>“Complex I inhibitors have previously been proposed as a cancer treatment. If these inhibitors show promise in future studies, they could potentially target cancerous cells while sparing oocytes,” explains senior author Dr Elvan Böke, group leader in the Cell &amp; Developmental Biology program at the CRG.</p> <p>The team plan to continue this research to discover the exact energy source that human egg cells use instead of complex I.</p> <p>“One in four cases of female infertility are unexplained – pointing to a huge gap of knowledge in our understanding of female reproduction. Our ambition is to discover the strategies (such as the lack of complex I) oocytes employ to stay healthy for many years in order to find out why these strategies eventually fail with advanced age,” concludes Böke.</p> <p><strong>This article originally appeared on <a href="https://cosmosmagazine.com/science/human-eggs-oocytes-dormant-metabolism/" target="_blank" rel="noopener">cosmosmagazine.com</a> and was written by Imma Perfetto.</strong></p> <p><em>Image: Shutterstock</em></p>

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7 surprising fertilisers for your garden

<div class="page-header clearfix"> <div class="tg-container"> <div class="detailPageHeader"> <div class="postIntro">Feeding your plants shouldn't mean buying a plastic container full of synthetic fertilizer. Often, you can feed your garden with what you have around your home. And with these fertilizers, you're often reusing or recycling some old product to help your garden, making you even greener. Here are seven ways to do just that:</div> </div> </div> </div> <div class="tg-container categorySection detailSection"> <div id="primary" class="contentAreaLeft"> <div class="share-buttons"> <div class="addthis_inline_share_toolbox" data-url="https://www.readersdigest.com.au/gardeing-tips/7-fertilizers-for-your-garden" data-title="7 Surprising Fertilizers for Your Garden | Reader's Digest Australia" data-description="Feeding your plants shouldn't mean buying a plastic container full of synthetic fertilizer. Often, you can feed your garden with what you have around your home. And with these fertilizers, you're often reusing or recycling some old product to help your garden, making you even greener. Here are seven ways to do just that:"> <div id="atstbx" class="at-resp-share-element at-style-responsive addthis-smartlayers addthis-animated at4-show" aria-labelledby="at-b26d7a27-eff5-44ce-81e8-3d02c64ce5ce"> <p><strong>1. Ammonia</strong></p> <p>Give the alkaline-loving flowering plants and vegetables in your garden — such as clematis, lilac, hydrangea, and cucumbers — an occasional special treat with a shower of 1/4 cup ammonia diluted in 1 gallon (3.7 litres) water. They’ll love the boost in nitrogen.</p> <p><strong>2. Baking soda</strong></p> <p>Give your flowering, alkaline-loving plants, such as clematis, delphiniums, and dianthus, an occasional shower in a mild solution of 1 tablespoon baking soda in 2 quarts (2 litres) water. They’ll show their appreciation with fuller, healthier blooms.</p> <p><strong>3. Bananas</strong></p> <p>Banana peels, like the fruit itself, are rich in potassium — an important nutrient for both you and your garden. Dry out banana peels on screens during the winter months. In early spring, grind them up in a food processor or blender and use it as a mulch to give new plants and seedlings a healthy start. Many cultivars of roses and other plants, like staghorn ferns, also benefit from the nutrients found in banana peels; simply cut up some peels and use them as plant food around your established plants.</p> <p><strong>4. Coffee grounds</strong></p> <p>It isn’t the caffeine in coffee grounds that garden plants like azaleas, rosebushes and evergreens love, it’s the acidity and aeration the grounds provide — not to mention nitrogen, phosphorous, and trace minerals. Just be sure to dig the grounds into the soil to keep them from becoming moldy. Dig about ¾ cup of grounds into the soil near the roots, repeating once a month. And don’t overdo it. Fertilizing even acid-loving plants with coffee grounds too frequently could increase soil acidity to undesirable levels.</p> <p><strong>5. Fireplace ashes</strong></p> <p>Hardwood ashes from your fireplace will supply potassium and phosphorous to garden plants. Just make sure not to use wood that has been treated with preservatives or anything else. To fertilize plants, spread a half-inch layer of ashes a few inches from the stem and dig it into the soil. However, if you store ashes outside, protect them from the rain or their nutrients will be depleted, and don’t use ashes around potatoes, since ash can promote potato scab.</p> <p><strong>6. Matchbooks</strong></p> <p>Matchbooks as fertilizer? Yes! But only when you want to add sulfur to the soil to lower the pH for acid-loving plants. Tear out the matches from several matchbooks and toss them into the bottom of planting holes for impatiens, hydrangeas, azaleas, and gardenias.</p> <p><strong>7. Tea</strong></p> <p>Sprinkle new or used tea leaves (loose or in tea bags) around your rosebushes and cover with mulch to give them a midsummer boost. When you water the plants, the nutrients from the tea will be released into the soil, spurring growth. Roses love the tannic acid that occurs naturally in tea. Likewise, schedule an occasional teatime for your ferns and other acid-loving houseplants. Substitute brewed tea when watering the plants. Or work wet tea leaves into the soil around the plants to give them a lush, luxuriant look.</p> <p><em>Written by Reader's Digest Editors. </em><em>This article first appeared in <a href="https://www.readersdigest.com.au/gardeing-tips/7-fertilizers-for-your-garden">Reader’s Digest</a>. For more of what you love from the world’s best-loved magazine, <a href="http://readersdigest.innovations.co.nz/c/readersdigestemailsubscribe?utm_source=over60&amp;utm_medium=articles&amp;utm_campaign=RDSUB&amp;keycode=WRN93V">here’s our best subscription offer</a>.</em></p> </div> </div> </div> </div> </div>

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Homemade rose fertiliser

<p>Roses love humus, and soil rich in organic matter will result in healthy plants and generous flowers. Fork in compost, animal manure, shredded and washed seaweed, small dead animals and birds, or a bit of blood and bone – whatever you have access to.</p> <p>If you can get your hands on a bag of lucerne chaff, fork in a cupful around each rose. It works wonders.</p> <p>If you can't easily get organic matter, commercial fertilisers for roses are fine. Follow the maker's instructions and don't be tempted to overfeed. The plant can assimilate only a certain amount and there will be plenty of opportunities for additional feeding through the season. </p> <p>Or you can be adventurous and try the magic recipe given to <em>NZ Gardener's</em> long-time rose columnist Barbara Lea Taylor by an elderly rose nurseryman many years ago, and passed on from one gardener to another ever since due to its almost miraculous effect.</p> <p>You can buy these ingredients at garden centres or big department stores: </p> <ul> <li>3kg sulphate of ammonia </li> <li>1kg iron sulphate</li> <li>2.5kg potash </li> <li>1kg dried blood</li> <li>1kg Epsom salts</li> </ul> <p><strong><span style="text-decoration: underline;">Method:</span></strong></p> <ol> <li>Mix it all up in a wheelbarrow and give each rose about 2 tablespoons forked in and watered around the drip line. Very large bushes and climbers might need more.</li> <li>If you have some left over, it will store well if you keep it in a dry place, and you will need to feed the roses again in December.  </li> <li>If the soil is dry, don't forget to water well after applying fertilisers of any kind. No fertiliser is going to do anything for a rose if it is lying on top of the soil.</li> </ol> <p><em>Republished with permission of <a href="http://www.stuff.co.nz/" target="_blank"><strong><span style="text-decoration: underline;">Stuff.co.nz.</span></strong></a></em></p>

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Why reading is like fertiliser for the mind

<p>When I was 7 years old, and long before the internet, I remember my excitement as I waited for my <em>Look and Learn</em> magazine to arrive at the local bookshop.</p> <p>My Nana had bought me a subscription and the glossy kids' mag would arrive from London each week. My first issue sported Ivan The Terrible on the cover, and it was the first instalment of a series on the Romanovs, a Russian Dynasty from 1613-1917. It was the same year Neil Armstrong landed on the moon. </p> <p>The dopamine must have surged at that young age because each week I would devour another episode about another Czar and my love of reading and history deepened and my imagination accelerated. Moscow has always been my number one must-visit country and it's hard to believe it has taken me nearly half a century to get here. </p> <p>Visiting Moscow, Red Square and the Kremlin has been worth the wait. Having visited the Far east and Kamchatka Peninsula and slid down Siberian volcanoes on my snowboard, it's special to visit Moscow and see my childhood dreams become a reality. Russia is at times like another planet and the once Soviet powerhouse has moved with the times. The irony is not lost on me to see a large statue of Karl Marx nestled between luxury brands like Bentley and Maserati in the next block. </p> <p>The neurons of imagination and delight fire in my brain as the glossy images of the magazines of childhood spring to life. Which is the point of this story. Reading is like fertiliser for the mind, young or old. Reading about far-off places and a thirst for knowledge surely creates and strengthens the neural network of creativity and discovery. Books and stories, however you access them, spark the imagination and help you escape like nothing else. </p> <p>As I will be spending a month on a boat in the Russian arctic, I posted a request on my Facebook page for good books to read on a journey devoid of news and Netflix. I have been humbled and thrilled at the efforts my friends have gone to, to suggest great titles and epic reads relating to this part of the world. The history and imagination of the region is as mind-blowing as the frozen steppes that beckon. </p> <p>The ability to download volumes of stories on to a device makes reading accessible like never before. Instead of waiting a week for a printed magazine as a child, I can hit a button and buy multiple books in a matter of minutes and not exceed my baggage allowance. </p> <p>It's an appetite that can be easily satisfied, and the only barrier is your credit card limit, not the airline's check-in counter. I would hate to think how many kilos of words I have downloaded to devour and digest at a later date when I get hungry for mental magic. </p> <p>Books are magic: they create magical images and sequences that feed our brain.  I have been a reader from a young age and my life would be very different without the books that have shaped it. In fact, a book I picked up in a store in Fremantle, Perth about a shipwreck in New Zealand's sub-Antarctic islands in 1864 has lead me here, sitting in a Murmansk hotel in Russia writing this article and waiting to set sail. My mind will not starve – I have the megabytes of yarns and tales to read and the words I will create of my own in the frozen Russian arctic. </p> <p>So feed your mind, start reading – or even writing – your own book and escape to somewhere else soon.</p> <p><em>Written by Dr Tom Mullholland. Republished with permission of <a href="http://www.stuff.co.nz/" target="_blank"><strong><span style="text-decoration: underline;">Stuff.co.nz</span></strong></a>.</em></p>

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5 natural fertilisers that can be found in your house

<p>You don’t need to go further than your own home to find the ingredients for all-natural fertilisers that will meet all of your garden needs.</p> <p><strong>Coffee grounds –</strong> Acid-loving plants such as tomatoes, blueberries, roses and azaleas appreciate a caffeine hit too. Sprinkle on the soil before watering.</p> <p><strong>Banana peels –</strong> Roses love potassium so throw a couple of peels in the hole before you plant. Otherwise, bury peels under mulch so it can compost naturally.</p> <p><strong>Egg shells -</strong> Crush the egg shells and sprinkle into soil near tomato plants. Egg shells are 93 per cent calcium carbonate, helping fend of blossom end rot.</p> <p><strong>Seaweed –</strong> Both fresh and dry versions work well. Chop up a bunch of seaweed and place in a bucket of water. Let it sit for a couple weeks, loosely covered. Use the mixture on soil and foliage. Otherwise, let seaweed dry out to a crisp and crumble it over soil.</p> <p><strong>Grass clippings –</strong> Finally a reason not to pick up those grass clippings after mowing the lawn. Clippings make excellent fertilisers, adding precious nitrogen back to the soil. Plus, they’re free! Short clippings decompose quickly so if you mow often enough, it won’t grow to unmanageable and unsightly levels. Alternatively, you can mix grass clippings into bucket of water. Let it sit for a couple of days. Mix one cup of the grass tea with 10 cups of water, and apply to base of plants.</p> <p><strong>Related links:</strong></p> <p><span style="text-decoration: underline;"><em><strong><a href="http://www.oversixty.co.nz/lifestyle/home-garden/2015/12/homemade-remedies-for-the-garden/">Homemade remedies for the garden</a></strong></em></span></p> <p><span style="text-decoration: underline;"><em><strong><a href="http://www.oversixty.co.nz/lifestyle/home-garden/2015/12/household-tricks-from-the-1900s-2/">More great vintage household tricks from the 1900s</a></strong></em></span></p> <p><span style="text-decoration: underline;"><em><strong><a href="http://www.oversixty.co.nz/lifestyle/home-garden/2015/11/10-ingenious-gardening-tricks/">10 ingenious gardening tricks</a></strong></em></span></p>

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Why you absolutely do need to fertilise your garden

<p>If you are fertilising your plants and thinking, “Do I really need to do this?” then read on.</p> <p>The main reason for fertilising your garden plants is to replace lost nutrients. The second reason is because plants that come from soil with different nutritional content to your garden soil will need fertilising in order to grow. A third reason to fertilise is because over time an established plant will use up all of the nutrition from the soil around it. Need a fourth reason? Some plants that have been bred to be “producers” – think vegetable plants, your lawn, or roses – and need more of the good stuff in order to keep going.</p> <p>Rather than thinking of fertiliser as food for plants, think of it more as something that helps your plants reach their full potential.</p> <p><strong>So what are the major elements that plants need to grow?</strong></p> <ul> <li>Nitrogen – most important for leaf growth.</li> <li>Phosphorus – this encourages development of roots, seedlings, flowers, fruits and seeds.</li> <li>Potassium – helps give the plant strength, protect it from disease, encourage water uptake, and gives better quality flowers, fruits and seeds.</li> </ul> <p><strong>What types of fertilisers are there?</strong></p> <p><strong>Organic fertilisers</strong></p> <ul> <li>Animal Manures – While you do need a lot to make an impact (as their nutritional value is quite low), these are good for improving the structure of soil.</li> <li>Chicken and Sheep Manure Pellets – As the manure has been compressed and dried it will release the nutrients slowly over time.</li> <li>Blood and Bone – A great fertiliser that releases nutrients very gently. Made from the waste products abattoirs. Please note it doesn’t contain potassium.</li> <li>Green Manure Crops – A plant from the pea family (such as peas, beans, clover or alfalfa) is grown specifically as it can trap atmospheric nitrogen. It is then dug into the soil after it flowers.</li> </ul> <p><strong>Non-organic fertilisers</strong></p> <ul> <li>Powdered and granular NPK fertilisers are available in various formulations depending on the plants you are fertilising (for instance lawns or camelias). They need plenty of water to help the soluble nitrogen dissolve and avoid root issues.</li> <li>Water soluble and liquid fertilisers will quickly dissolve when added to the watering can and then applied directly to the plant.</li> <li>Controlled release fertilisers are a revolutionary new way to fertilise and have become popular in nurseries. The fertiliser is covered with a protective coating, which means the nutrients are released slowly. It is also affected by temperature, which means more nutrients are released when the plant is growing and needs it.</li> </ul>

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