This tumblr's for all the great men and women of science for whom we owe our current understanding of the natural world; their achievements, their failures, and even their quirks, we celebrate them all.
For Science. For Inquiry. For Humanity.
How Do Jellyfish Sting?
the science of cnidocytes and nematocysts
jellyfish don’t sting through electricity or by touch. Jellyfish sting through a special type of cell called a Cnidocyte, there are three types of cnidocytes currently known. Spirocysts which entangle their prey, Ptychocysts which build tubes for tube anemones and the most well known Nematocysts. Nematocysts consist of a toxic barb which is coiled on a thread inside the cindocyte, when triggered the barb is ejected almost instantly taking only 700 nanoseconds to fire and firing with a force of five million g’s. A cindoctye can only fire once, and must be replaced when fired a process that could take 2 days.
Genus cassiopea is a genus of jellyfish commonly known as Upside-down jellyfish found in coastal regions around the world in mangroves, mudflats and turtle grass. they earned the name upside-down jellyfish due to the Medusa stage usually lives upside down with the tentacles in the “air” and the bell on the bottom like a sea anemone, they then sit on the floor and feed. their sting is relatively mild as the animals are primarily photosynthetic. they have a symbiotic relationship with the urchin crab (Dorippe frascone) who picks up the cnidarian and carries it on its back and the jellyfish defends the crab. the genus includes 8 species: C.andromeda,C.depressa,C.frondosa,C.medusa,C.mertensi,C.ndrosia,C.ornata,C.xamachana. people often think something is wrong with the animals as they sit on the bottom and just pulse but they are fine.
*Also yay 200th post!!
People, it’s time I tell you about Siphonophores.
They are an order of colonial sea jellies in the class Hydrozoa. Colonial, meaning their bodies, though seemingly one orgamism, are constructed of many miniscule individual organisms. most of ya’ll know the Portuguese Man O’ War, with its iconic bell (the floaty bit, it looks like a helmet) and its reputation for being a scuba-diver-entangling, murderin’ douchebag, but fewer are acquainted with the impressive and creepy (read: cuddly + adorable) Praya dubia. It’s one of the largest invertebrates in the world, it’s bioluminescent, and its sting could paralyse and/or kill you.
Big Week for “Synthetic” Biology
A jellyfish made of silicone, and a bacterium made in silico
Synthetic biology is traditionally thought of as repurposing existing or designing new biological parts to do novel things. But in a larger sense, it can be thought of as the ability to create biological systems outside the limitations of pesky things like global and evolutionary time scales. This week marks two really stunning bio accomplishments, each fitting into their own definition of “synthetic”.
Whoa, Jellyman: Cal Tech and Harvard biophysicists announced that they had created a sort of “synthetic jellyfish” this week (pictured above left). By taking thin, carefully designed sheets of silicone and layering rat heart muscle cells over them, they were able to make a bell-shaped living device that pulsed and swam just like the bell of a jellyfish.
Heart muscle cells, or cardiomyocytes, naturally grow together in sheets and will automatically “beat” in a petri dish (with the help of a little calcium). If you provide an outside voltage (like a pacemaker) they will beat in unison! The rat-heart-silicone “medusoid” shape contracted, with the beating cells pulling on the silicone substrate just as a jellyfish’s own muscle cells act on its bell to swim.
Of course, this isn’t a real jellyfish, but for extra credit you can read Ferris Jabr’s take on what it would actually take to build one.
Byte-size Bio: The other big news this week comes from Stanford and the J. Craig Venter Institute (gracing the cover of Cell this week, above right). Not content with making the world’s first synthetic organism and synthetic genome (Venter’s ambition knows no bounds), they decided to build a computer model of an entire bacterium. Well, mostly.
They modeled, on a very general scale, the tiny bacterium Mycoplasma genitalium, which only has 525 genes compared to our ~20,000, and all of its internal processes on 128 computers operating for 10 hours. To complete a single cell division, it required half a gigabyte of data. But you have to be careful before you call this a completely “simulated organism”. Normal cells have many, perhaps hundreds, of just different types of genes, and they interact in myriad ways … we have just begun to scratch the surface of those networks. Just look at how complicated even the tiny changes in a cancer cell can be!
By simplifying their model down to 28 minimal systems, their computer program matched the bacterium’s biology as we know it. But a more “realistic” model is going to be exponentially more complicated. Here’s some collected reactions at Tree of Life. But, still … wow!
Modern biology has done a very good job at describing the function of individual genes and proteins, but our next chapter lies in how these interactions build into systems. The “-omics” era will be one where we map how the thousands of parts that we are made of combine to make us whole.Simulations like this will be at the leading edge of that era. But we have a long way to go … how many computers would it take to model the trillions of cells in the human body?
U.S. firm The Amazing Jellyfish (theamazingjellyfish.com) takes the bioluminescent bodies of creatures that have died of natural causes and encase them in resin, thus preserving not just their bodies, but also their incredible glow-in-the-dark properties.
1. STELLAMEDUSA VENTANA
2. AEGINURA GRIMALDII
3. ATOLLA JELLY
5. PORALIA RUFESCENS
6. RED LOBATE CTENOPHORE
7. SOLMISSUS INCISA
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The Lion’s Mane Jellyfish notably ‘Arctic sea jellies’ has made a sensational appearance in literature, most notably in Sherlock Holmes’s ‘The Adventure of the Lion’s Mane.’ However, lion’s mane jellyfish is nowhere close to as dangerous as it is made out to be in popular culture. A sting from the lion’s mane jellyfish is not only incapable of causing human deaths; all it does is cause an itchy rash and mild burning sensation. Although the rash can be painful for sensitive individuals and the toxins in the venom may cause an allergic reaction, the stings from a lion’s mane jellyfish can be treated by application of vinegar.
However, lion’s mane jellyfish are very interesting marine creatures. To begin with, they live in the harshest weather conditions. They are found in the freezing cold waters of the Arctic Ocean and Northern Pacific Ocean during the coldest months of the year. They rarely descend below 42 degrees latitude and are not found in the southern hemisphere at all.
The lion’s mane jellyfish can attain enormous size. In fact, the largest Lion’s Mane jellyfish is not merely the largest species of jellyfish in the world; it is the largest animal in the world. The one specimen of Lion’s Mane which was found in Massachusetts Bay in 1870 was over 7 feet in diameter and its tentacles were longer than 120 feet in length.
However, the bell of the Artic Lion’s Mane is known to be able to grow up to 8 feet in diameter, and their tentacles can acquire the length of 150 feet. That is much longer than blue whale, which is generally thought to be the largest animal in the world.