Latest news with #hemifusomes
Daily Mail
15 hours ago
- Science
- Daily Mail
Scientists are BAFFLED after discovering a mysterious new structure hiding inside human cells
Scientists have discovered a mysterious new structure lurking inside every human cell. These tiny structures, dubbed hemifusomes, are just 200 to 400 nanometres in diameter. To put that into perspective, that's about 500 times thinner than a human hair. Scientists believe the structures play a critical role in helping our cells recycle and discard waste materials. Co-author Dr Seham Ebrahim, of the University of Virginia, says: 'It's exciting because finding something truly new inside cells is rare - and it gives us a whole new path to explore. 'This is like discovering a new recycling centre inside the cell. 'We think the hemifusome helps manage how cells package and process material, and when this goes wrong, it may contribute to diseases that affect many systems in the body.' In the future, the finding could help scientists to develop treatments for conditions such as Hermansky-Pudlak syndrome - a rare genetic disorder that can cause albinism, vision problems, and lung disease. Since hemifusomes are exceptionally small, the researchers needed extremely sensitive equipment to spot them. The team used a method called cryo-electron tomography, in which samples are rapidly frozen to around -150°C (-240°F) before being sliced very thinly. The scientists then took lots of photos with a powerful microscope which uses electrons instead of visible light. This allowed them to look at extremely small structures just as they would appear in a living cell by freezing them in time, rather than damaging the samples by trying to preserve them. Using this method, a team of researchers from the University of Virginia spotted structures which looked like two thin bubbles stuck together at the edges. The researchers believe hemifusomes produce vesicles - tiny sacs that act as 'mixing bowls', as well as making structures made of lots of these vesicles. Dr Ebrahim says: 'You can think of vesicles like little delivery trucks inside the cell. 'The hemifusome is like a loading dock where they connect and transfer cargo. It's a step in the process we didn't know existed.' By placing vesicles inside themselves, hemifusoles can store and combine different chemicals and waste products. Scientists think that some diseases might be caused when this process is disrupted By building vesicles, and even putting vesicles inside each other, the hemifusomes allow our cells to package and sort proteins or recycle parts of the cell. One thing that the researchers were surprised to find is that the layer which connects the hemifusome and the vesicles is much thinner than scientists previously thought possible. This 'hemifusion diaphragm' sticks to the two structures together but doesn't let their contents mix, like two water balloons that have melted together at the edges. Previously, scientists thought these types of structures would be too unstable to do anything useful in our cells. But in the hemifusome, the researchers spotted them playing a really important role in keeping our cells healthy. That discovery could have big implications for how we understand and treat diseases which interfere with our cells' recycling functions. Dr Ebrahim says: 'We're just beginning to understand how this new organelle fits into the bigger picture of cell health and disease. 'Now that we know hemifusomes exist, we can start asking how they behave in healthy cells and what happens when things go wrong. That could lead us to new strategies for treating complex genetic diseases. Cells in numbers Scientists believe the first known cells originated on Earth 3.8 billion years ago. The diameter in centimeters of most animal cells is 0.001 to 0.003, making them invisible to the naked eye. In 1665, British scientist Robert Hooke coined the term cell to describe the porous, grid-like structure he saw when viewing a thin slice of cork under a microscope. There are 200 different types of cells are in the human body. There are 24 hours in an animal cell cycle, the time from a cell's formation to when it splits in two to make more cells. A human red blood cells lives about 120 days. Each day, approximately 50 to 70 billion cells die in the human.
Yahoo
07-07-2025
- Health
- Yahoo
Whoa—Scientists Found a Part of Human Cells We Never Knew Existed
"Hearst Magazines and Yahoo may earn commission or revenue on some items through these links." Here's what you'll learn when you read this story: Hemifusomes are fused vesicles, or sacs of fluid, that were previously unknown to exist inside cells. They were discovered using cryo-electron tomography, which literally freezes them in time, and confirmed to be actual organelles and not just background noise. Because hemifusomes collect and recycle junk proteins, they could mean more effective treatments for diseases caused and aggravated by protein plaque buildup, such as Alzheimer's. Back in high school biology, most of us learned about the innards of a cell, or its organelles, from ribosomes to mitochondria to the endoplasmic reticulum, and probably had to identify them on our midterms. Now, an unexpected discovery will probably soon rewrite those textbooks. The hemifusome is the new organelle that high school students (much to their chagrin) will have to remember. Biophysicist Seham Ebrahim of the University of Virginia and her team of researchers were observing mammalian cells when they discovered hemifusomes, which previously eluded detection because they are even smaller than mitochondria and can easily blur or be mistaken for background noise. These nano-orbs, which look like they have, noses bear an uncanny resemblance to BB-8 or the profiles of certain Muppets. Pop culture references aside, their function of organizing, cleaning up, and recycling proteins could potentially unlock new treatments for genetic and neurodegenerative diseases. Hemifusomes consist of two vesicles, which are membrane sacs filled with liquid and formed by hemifusion, meaning that the smaller of the two is fused to the larger one like a hemisphere, almost as if its other half is missing. This occurs when the outer layers of two membranes merge first while the inner membrane layers stay open until a thin connection between them forms a new vesicle. The attached vesicles are sometimes found on the outside of the organelle and sometimes on the inside, and though where exactly these vesicles originate is still unknown, hemifusomes are thought to facilitate the formation of new vesicles that transport materials throughout the cell. This is probably how they take out cellular trash. Ebrahim used cryo-electron tomography, or cryo-ET, to observe and image hemifusomes. The cells, which were kept at cryogenic temperatures, were imaged in two dimensions using an electron microscope. Superfast cameras then took multiple photos of the frozen cells and their organelles. From these photos, single images were created using algorithms, upgrading the 2D images to 3D. 'Our observation of hemifusomes in four different cell lines originating from various species and tissues and frozen as close as possible to their native state suggests that they may be common components of the cell periphery in a wide range of cells and tissues,' she said in a study recently published in Nature Communications. Something else the researchers wanted to explore was what kind of relationship hemifusomes had with endosomes, which are vesicles that transport extracellular material into the cell via the process of endocytosis. The cell's plasma membrane will fold inward to surround matter, such as food molecules, in the surrounding fluid. These molecules are then taken in by the cell, whose plasma membrane pinches off to create an endosome that carries them into the cytoplasm. Endosomes can also form through the fusion of vesicles that already exist within the cell. Ebrahim traced the activity of endosomes and hemifusomes, but they did not appear to work together. What makes hemifusomes so important is how they collect and recycle junk proteins. Many studies have shown that the buildup of protein plaque in the brain can cause and aggravate neurodegenerative diseases such as dementia and Alzheimer's, and more understanding about how these organelles operate could lead to the development of treatments that work with them. 'Future research should focus on determining whether hemifusomes and compound hemifusomes are present in other cellular regions,' Ebrahim said, 'and on elucidating the molecular mechanisms underlying their formation, stability, and function, as well as their broader implications for cellular physiology and pathology.' You Might Also Like The Do's and Don'ts of Using Painter's Tape The Best Portable BBQ Grills for Cooking Anywhere Can a Smart Watch Prolong Your Life?
