Fanny Hesse, the mother of microbiology

There are unsung heroes in the scientific world. They do things behind the scenes in every lab to support the scientists in companies, academia, or government research institutes. They wash the glassware like beakers and flasks. They sterilize materials like medical operating tools. They lay things out for lab lessons. Because of their roles, they go unnoticed and unnamed, although sometimes if they are technicians, a researcher who presents his data at a conference might end his slideshow with their names and faces with a hearty thanks.

This article is about one of those heroes whose name should have been in the limelight for her single contribution to the world of microbiology. Her name is Angelina Fanny Eilshemius. Fanny was the oldest of ten children. She was born on June 22, 1850 in New York City to an import merchant. Her father was Dutch but moved to the U.S. from Germany only 8 years before Fanny was born. He was so successful that he was able to afford to send Fanny to a finishing school in Switzerland at the end of the Civil War, when she was 15. She had already learned cooking and housekeeping from her mother and servants, so the purpose of the finishing school was to teach her French and economics.

photo from alchetron.com

Walther Hesse, her future husband, was a German physician who spent a year in the medical corps. His brother introduced him to the Eilshemius family including Fanny in 1871. A year later, Fanny and her family went on vacation to Europe, and she met up with Walther again in Germany. They were married in 1874, so obviously they had hit it off from the start.

Walther was appointed as a county physician in a uranium mining town on the border of Germany and Czechoslovakia in 1877. (Not long after that, the nearby mines provided ore to Marie and Pierre Curie for their investigations on radium in the ore.) Dr. Hesse spent 10 years there mainly treating miners with lung cancer. He grew deeply interested in environmental hygiene, especially concerning dust contamination and carbon dioxide in the mines, homes, and schools. He was first introduced to the science of microbiology when he became responsible for smallpox vaccines in the community.

His and Fanny's big move was in 1881 when Walther's interest in studying bacteria caused him to take a sabbatical at the Imperial Health Agency in Berlin. The man in charge there was Robert Koch, one of the giants in the field of microbiology then. Koch had already discovered the cause for anthrax, cholera, and tuberculosis before Hesse arrived, and that was perfect timing for both people. With other researchers there, they pioneered many lab techniques in use today.

This is where Fanny enters the picture.

In addition to taking care of their sons, Fanny helped out in Walther's lab as he worked under Koch. Not only did she draw images from his microscopic views (a talent inherited from her grandfather, painter Louis Léopold Robert), but she was also a technician to prepare the broths to grow bacteria. One problem that everyone encountered was specific to growing bacteria that they were studying.

Fanny and Walther Hesse around 1872

Researchers used liquid broths that were rich in nutrients, but in order to find just one type of bacteria, they had to grow them on something hard. That way, if they were spread out in a diluted solution, each bacteria would grow separated from the others and make a tiny blob called a colony. That was a pure growth of just one type of bacteria, exactly what the researchers needed. 

Bacterial colonies from a cough on a Petri dish (from microbiologysociety.org)

Koch started doing this with thin slices of spoiled potatoes when he saw that they had bacteria and mold growing on them. But they didn't grow everything. People had already known that things grow naturally on foods. Bartolomeo Bizio investigated a "bloody bread" epidemic in Italy around 1820 and identified the bacteria growing on it. In 1872, Joseph Schroeter used potato, coagulated egg white, meat, and bread as surfaces that some bacteria would grow on. But using food was imprecise, and Koch was a stickler for precision.

White splotches on the right half are bacterial colonies on a potato slice.

So, Koch took his liquid broths and made them a little harder by adding gelatin. The problem Koch found was that when they were put into test tubes and incubated at body temperature, the gelatin melted back into a liquid form. Some bacteria can also digest gelatin and make it liquid. Hesse was trying to study bacteria growing from air samples at the same time, but hot summer temperatures also melted the gelatin. Hesse smeared a thin layer of gelatin on the inside of test tubes for his air contamination experiments, but he was frustrated when they easily melted and ran down the tube into a pool at the bottom instead of staying as a smooth flat layer where he hoped to count and identify what had grown there.

Walther then noticed that Fanny's puddings and jellies at home didn't suffer in the heat, so he asked what she did to prevent that. She told him she had replaced the gelatin with agar. As a child in New York City, while she was learning to cook, a neighbor who had immigrated from Java told her about agar, an extract from red algae used as a gelling agent in warm climates. (Agar is also called agar-agar in Malay language.)

Red algae (Wikipedia)

Walther quickly tested it and found that nutrient broth with agar added could be sterilized, and that bacteria did not eat it, plus it could be stored for a long time. That was what was needed, especially for some experiments with slow-growing bacteria like in tuberculosis. This was the solution (no pun intended) he and Koch needed!

The picture below show 3 ways agar can be used to grow bacteria, now and back in the days of Hesse and Koch. One is on a flat covered plate called a Petri dish. Another (left) is a deep tube, where you stab a needle with bacteria on it and see where it grows -- near the top where there is more oxygen, or near the bottom where there isn't any. If you pour agar into a tube and tilt it at an angle before it hardens, you get a slant (right). Putting bacteria on that surface allows it to grow like on a Petri dish but taking up less space. The middle tube has no agar in it; it's just a liquid broth which is good for bacteria that can swim.

Photo from microbiologynotes.com

Koch and other researchers developed different ways to grow bacteria on agar that was put into Petri dishes. Sometimes they wanted to count how many were there, so they took a broth and spread it on top of agar or mixed it with liquid agar before it hardened. If they had a sample of something and wanted to get just one colony growing from a single bacteria, they could also streak the sample with a wire loop onto the surface of the agar That way, if the sample was mixed with other bacteria, each one could be seen by its color or texture. These techniques are used today.

Results of 3 types of agar plate growth of bacteria

Fanny Hesse's simple home cooking advice about agar revolutionized how researchers could study bacteria. In fact, after agar was introduced to Hesse, it took Koch less than a year to use the technique and discover the bacteria that causes tuberculosis. In his paper, though, he only casually mentioned changing from gelatin to agar and never explained why. Neither Fanny nor Walther was given any credit for it, either. When Koch wrote up his landmark research on tuberculosis where he used agar to culture the bacteria, here is all that he said about this new method:

“The tubercule bacilli can also be cultivated on other media…they grow, for example, on a gelatinous mass which was prepared with agar-agar, which remains solid at blood temperature, and which has received a supplement of meat broth and peptone.”

Walther Hesse's grandson Wolfgang told this story and more, and he said that Fanny was so unassuming that she never mentioned this to the family. It wouldn't have been "proper". Her original drawings and Walther's notes have been kept by his descendants to this day. 

Here is a video showing how to streak an agar plate.

Here is Wolfgang Hesse's biographical account of Walther and Fanny.

Up to 1.7 billion T. rex dinosaurs lived on Earth, a new study found. But scientists aren't sure where all the bones went

Link to Business Insider article

Dinosaurs are popular topics for people of all ages. We have a fascination for them but especially the big ones. Tyrannosaurus rex (T. rex, "tyrant lizard king") is probably the most well known. But dinosaurs ranged in size from small dogs or horses to the behemoths like T. rex. So, how many dinosaurs lived? Charles Marshall, who is a paleontologist at the University of California, Berkeley, has recently done some calculating to answer that question for T. rex.

T. rex illustration from the article

Marshall and his team looked at reptiles alive today and came up with a ratio of their body size and the population density. In other words, how big they are has some bearing on how many can live in a certain number of square miles. That number was used to estimate the density, distribution, total biomass, and persistence of T. rex using fossil evidence we have now. They claim the numbers showed over 2 billion T. rexes lived overall (about 20,000 at any one time). Most T. rex fossils have been found in North America but some also in Asia and Australia. Only 32 complete skeletons have been found so far.

Range of T. rex in western North America

But the Business Insider article explains that Eva Griebeler from the Johannes Gutenberg University of Mainz, Germany figured slightly fewer of the T. rex species existed, about 1.7 billion. She said Marshall's number came from calculating one figure incorrectly. It's their rate of survival. We have no living T. rex today, so we have to estimate how long each one lived. But Griebeler used other animals still living for her calculations, as follows.

For small, birds, mammals, and lizards alive today, their survival looks like a straight line on a graph, with high percent of survival for young animals and lower as they get older. But the survival of large, long-lived reptiles living today are a different shape on the graph, and that data was what she used instead. Her paper carefully explained with very complex math just what the differences were compared to Marshall's work, and Marshall later complimented her on a better estimation of T. rex populations. Take this link for a simpler explanation.

Examples of 3 types of survivorship curves (Wikipedia)

Studying dinosaurs is difficult because they are no longer around. We have to rely on fossils and other evidence that can be found around them. But what is a fossil anyway? It's Latin name means "unearthed", which is a clue.

According to the British Geological Survey:

Fossils are the preserved remains of plants and animals whose bodies were buried in sediments, such as sand and mud, under ancient seas, lakes and rivers. Fossils also include any preserved trace of life that is typically more than 10,000 years old.

The first dinosaur fossil that we recognize was found in 1676 by Reverend Robert Plot, a curator of an English museum and a professor of chemistry. He found a 20-pound lower part of a thigh bone and thought it belonged to an ancient species of giant humans from the Bible. Although the bone was lost over time, drawings he made of it suggested many years later that it actually belonged to a dinosaur Megalosaurus. 

Plot's 1676 dinosaur bone and publication (Wikipedia)

Many other dinosaur bones were discovered after Plot. In 1827, geologist William Buckland was the first to accurately describe some as belonging to a giant lizard, the Megalosaurus ("large lizard"). But it wasn't until 1841 when English anatomist Sir Richard Owen came up with the name "dinosaur", meaning "terrible lizard". 

Megalosaurus fossils in the Oxford University Museum of Natural History

Fossils are usually found in sedimentary rock, the type that is formed when soil and other organic material settled (sediments) to the bottom of water. But they don't stay around as bone material. Skin and organs decay rapidly, but bones last longer. Since dinosaurs were around 65 to 240 million years ago, something has to preserve even hard material such as bone for that long a time.

• If the buried bone is exposed to mineral-rich fluids with a lot of minerals in them, the minerals move into the bone and replace the organic (carbon-containing) material to make stone fossils.
• Soft material like leaves can be compressed onto soft mud by top layers of sediment.

Photo from the British Geological Survey

• Another type of fossilization process is when a shell or bone decays completely, but the empty space that it leaves behind is filled in with sediment. This leaves a mold of the original shape.
• The rarest type of fossil preserves the original skeletons and soft body parts. Insects trapped in amber (tree sap that hardens) are a good example.

If you want to read more about Tyrannosaurus rex, check out fossilguy.com

Here's a link to fossils, how they are formed, and why we study them.

Here's a link to the history of dinosaurs.

Living mysteries: Why teeny-weeny tardigrades are tough as nails

Link to the article

https://www.snexplores.org/article/why-tardigrades-tough-space-dehydration

Can you name an animal with 8 legs? Spiders and octopi usually come to mind, but what about tardigrades, also known as "water bears"? These very small creatures were discovered 250 years ago and have continued to amaze scientists since then.

Light microscope image (left) and electron microscope image (right), from the article

The Science News Explores article describes many of their interesting features that demonstrate just how hardy the "tardies" are. They're really amazing.

Adult tardigrades are about 0.5 mm (0.020 in) long, so they are barely visible with the naked eye. Depending on font size, they may be the size of a period. They grow naturally in moss and lichen. German zoologist Johann Goeze discovered them in a pond in 1773 and gave them the dubious nickname of "little water bear". Four years later, Italian biologist Lazzaro Spallanzani wrote up his studies on them and labeled them Tardigrada, which means "slow stepper". Some people have also called them "moss piglets", but whatever the name, they are incredible.

As the article describes, tardigrades can somehow resist extreme environmental conditions. Spallanzani let them dry up, and they survived even though he thought they were shriveled up and dead. They had simply gone into a form of suspended animation like spores from plants or bacteria. That's called their tun state. The word comes from the German or Old English word for barrel, which is just what they look like. Current research is beginning to show that tardigrades have DNA segments that code for proteins that form gels or glass-like material in their hibernating stage, to protect them from damage with little water inside.

photo from the article

The article goes on to say that not only can they survive drying up, but you can't seem to kill them with X-rays, UV radiation, or gamma rays, or temperatures down to –273 °C (–459 °F). But what about higher temps? A biologist at the University of Copenhagen tested that on active and hibernating tardigrades. One was to take active tardigrades and put 20 them in small tubes with 1.5 mL (1/3 teaspoon) of water and turn up the heat to 4 temperatures. After they cooled down to room temperature for an hour, they were kept in the refrigerator with some food to prevent them from losing energy searching for it in an empty tube.

Experiment 1

The second experiment let the active tardigrades get used to 30 °C for 2 hours, then 35 °C for 2 hours, before splitting them into a tube of 35 or 40 °C for a day.

One third to half of them didn't survive at 37 °C, and none survived at 40 °C.

Experiment 2

The tardigrades that had been given time to acclimate survived 25% better at 37°C than in experiment 1, but not much.

A third experiment dried tardigrades on paper, then put them into tubes and heated them up to 40, 50, 60, 65 or 70 °C (104, 122, 140, 149, or 158 °F) for 24 hours or in another batch they were exposed to higher temps of 70, 80, 82, 85, or 90°C (158, 176, 180, 185, or 194 °F), cooled to room temperature for an hour, then rehydrated with water for another hour, then put them in the refrigerator.

Experiment 3

The tun tardigrades were still 91-98% alive after a day at 40-60 °C of dry conditions, and more than a third made it to 65 °C. The tun tardigrades that had only an hour of high heat exposure were 89-94% alive at 70-80 °C. Almost 80% made it to 82 °C, but that was the limit of their survival. Here's a link to the actual scientific paper.

Acclimating is a more natural condition, so who knows how well they will adapt to climate change? And if you think you might have them in your drinking water, boiling certainly seems to kill them even if they are hibernating.

The strangest part of tardigrades' survival is being so resistant to radiation. They aren't exposed to it in their natural environments, so why did they develop this superpower? Nobody is sure, but some are wondering whether their DNA can be used to improve a human's ability to survive in such dangerous conditions. That would be great if you are a soldier, a worker in a nuclear plant, or an astronaut.

Japanese researchers have tested that with human kidney cells in the lab. They found a special piece of DNA unique to a tardigrade. The strain of tardigrade is called YOKOZUNA-1. Yokozuna is the highest ranking in sumo wrestling, so it's no wonder they named this tardigrade for such toughness. It was originally found on moss on a bridge in Sapporo, where I now live!

This piece of DNA is called Dsup, meaning "damage suppressor". Its function is to make a protein to cover the DNA and shield it from UV radiation damage. Tardigrades also have DNA that do more efficient repairs of damage to their genetic material, so that explains their resistance with a twofold strategy. In 2020, scientists put the Dsup into tobacco plants, and in 2021 other scientists put it into human kidney cells, and in both cases, the cells were better protected against UV radiation.

As mentioned earlier, even supercold temperatures don't kill tardigrades. They were tested in 2007 for their survival in outer space by Ingemar Jönsson of Kristianstad University in Sweden when he sent them up in the European Space Agency's FOTON-M3 spacecraft. There was much more radiation in orbit than on Earth, so they didn't that survive well.

FOTON-M3 (left) and environmental exposure chamber (right) 

Israel sent its Beresheet lunar lander to the Sea of Serenity on the Moon in 2019, where the last U.S. Apollo mission (17) had landed. Unknown to many, it carried live tardigrades. An unfortunate loss of contact just before landing resulted in a crash. But people wondered whether the tardigrades survived thus contaminating the Moon's surface for future investigations of life signs there. Initially, the scientists thought it was possible they survived and could be returned and revived on Earth. In 2021, Alejandra Traspas, a doctoral student at Queen Mary University of London, wondered if the tardigrades could survive the physical impact alone. She put some into their tun state and fired them inside a hollow bullet into a sand target! They survived with the bullet speed of 3000 km/hr (1,800 mph) but not higher. Since Beresheet was expected to hit with greater force, they concluded the tardigrades would not have survived.

Why study tardigrades, aside from dreams of protecting astronauts, radiation workers, and soldiers? Some discoveries may help find solutions to Alzheimer's disease, vaccine stability, and crop stress.

For a great simplistic animated explanation on tardigrades, watch this YouTube video.

 Building a Satellite out of Wood? Use Magnolia

Link to article

It doesn't really make sense at first glance to imagine wooden satellites. We have grown up watching movies and real life videos of metallic spacecraft and manmade objects in orbit around Earth or sent into space for exploration. Wood? Isn't that a major step backwards in technology?

Wood paneled satellite image (from asia.nikkei.com)

Here are some reasons to consider wood. 

• It's cheaper than the current material, aluminum.
• It's a sustainable material.
• It's strong, flexible, and lightweight.
• It burns up better on re-entry than metal.
• It allows electromagnetic waves to pass through, so antennas can stay inside.

The United States actually used balsa wood for the Ranger 4 lunar explorer in 1962. The top spherical section filled with liquid contained a seismometer and was supposed to separate before the hard landing. The rest of Ranger 4 would land and take other measurements. But a malfunction caused Ranger 4 to crash without sending back any data.

Ranger 4 and its impact limiter top  (photos from universetoday.com)

In 2017, work in Japan began to test various woods under vacuum conditions on Earth. Kyoto University (Japan) looked at cedar, cypress, satinwood, magnolia, and zelkova after 6 months in a vacuum. No deterioration was seen in any samples, and the elastic properties for three seemed unaffected compared to the others.

Professor Koji Murata, member of Kyoto University's Biomaterials Design Lab, joined forces with Sumitomo Forestry and Japan's space agency JAXA with a plan in 2021 to send some wooden samples to the experiment platform of the Kibo module on the International Space Station (ISS). In March 2022, that plan was executed. 

They sent up 3 types of ordinary furniture wood to the ISS and exposed them to space to see how their quality deteriorated with temperature changes and cosmic radiation. The result? No warping, no cracks, no peeling, no other obvious problems.

The Kibo module and wood samples

You might wonder about other space junk that has fallen back to Earth. Doesn't it completely burn up except for the larger denser parts that land? Actually, no. As things begin to burn up, they loosen and fall apart. Tiny fragments may spray back into orbit again. They are nearly impossible to track, and since they are traveling at 28,000 km/hr (17,000 miles/hr), even a small metal part can cause a lot of damage if it hits another satellite or a manned craft. See the window crack below.

Window damage on the ISS (NASA)

If a satellite housing is composed of wood, radio waves can pass through without interference. The WoodSat or LignoSat could therefore be made more compact for launch, and it wouldn't need to open up and allow for a radio antenna to unfold. Recently, the European Space Agency's Jupiter Icy Moons Explorer (JUICE) had this sort of problem with its Radar for Icy Moons Exploration (RIME) antenna and wasted more than three weeks to fix it by jostling the craft remotely. 

Here is a short video explaining the Japanese wooden satellite proposal.

Here is another informative video about wood in space from a DIY woodworking YouTuber!

Finally, a very understandable engineering analysis (video) of using wood for space products.

 Marie Curie, A Handful of Scientific Firsts

There are far too few women recognized in science, but one whose name is usually on the top of the list when people are asked to name any is Marie Curie (born Marja Sklodowska in Poland on November 7th, 1867). I highly recommend reading her biography written by her daughter Eve in 1937. You could choose any of the half dozen or more others, and I admit I haven't read them, but this one was good. The 2019 movie Radioactive, starring the talented Rosamund Pike, was based on a different biography, and it was poorly edited, so I don't recommend watching it.

photo from Amazon.com

So, why do we remember Marie Curie? A glance at a science book will tell you some interesting facts:

• She was the first female to receive a Nobel prize (1903 in physics, with Pierre Curie and Henri Becquerel). This makes her and her husband the first married couple to share a Nobel, too.
• She coined the term "radioactive" during her studies that earned her the 1903 Nobel.
• She was the first person to win a second Nobel prize (1911 in chemistry for discovering radium and polonium).
• She is the only person to win two Nobel prizes in different scientific fields (Linus Pauling has won 2 Nobel prizes, but they were in medicine and peace).
• She was the first female to earn a doctorate in physics and gain professor status at the University of Paris (1906).

Marie was a pure scientist, a pure researcher. Even before entering university, she did her best to improve herself by reading anything in science that she could, on any topic. Under Russian rule, Poland suffered a hard lifestyle, but Marie demonstrated her academic brilliance early in school. But education then and there kept discoveries from the outside world secret. So, to help spread learning to fellow members of the lower class, in high school she organized a group called the "Floating University", a grassroots movement to secretly teach anatomy, natural history, and sociology to young students and housewives. She even put off applying to university so her older sister Bronya would have a chance instead; Bronya would live away from home to attend medical school, while Marie worked as a governess for 3 years to support her. 

When Marie finally began university in Paris at age 20, she scrimped to live in a room with no heat, lights, or water. She'd read until her fingers were numb, and she hardly ate. But she was absorbed in math and sciences. She was analyzing rocks in a crowded lab, and a friend introduced her to Pierre Curie, 15 years older than her, who ran another laboratory there. So she began doing research there and fell in love with the mind of her future husband. They were so similar in their devotion to science, but they married and continued to work closely together.

In 1896, Wilhelm Roentgen discovered how to make X-rays. But he had a device to do that. Henri Becquerel noticed a "rare metal" called uranium also sent out rays that did similar things to X-rays, but they did it without adding any energy to them! Marie took this new knowledge and studied many materials and learned that the element thorium had this property, and she named it radioactivity. When she found more radioactivity in one material than the uranium and thorium in it could produce, she felt it was because a third radioactive element was there. A new element!

Roentgen's wife's hand via X-rays, a metal cross imaged from Becquerel's uranium

Marie and Pierre worked for years to purify this element, and when it was finally found in 1898, Marie gave it the name polonium in honor of her patriotism towards her home country. To do this meant examining an ore called pitchblende and refining it from huge quantities down to a tiny amount. And, they felt there was another element there adding to the radioactivity. They gave it the name radium even though they had not found it yet. Chemists that they talked to were very skeptical saying they didn't even know the atomic weight of radium, so the Curies had to show them a sample before they believed it existed.

Four years later, they did.

Pierre and Marie, from mariecurie.org.uk

They worked in an unused shed on campus, one with no floor, and with a leaky skylight that made the place hot in summer and freezing in winter. They crushed and treated with chemicals tons of scrap pitchblende from a nearby mine with the help of only one assistant. Marie did most of the heavy work shoveling and crushing and treating with chemicals to separate all the other elements in it, while Pierre did the careful measurements. One night, they left home when Marie said, "Suppose we go down there for a moment?" As they entered the dark lab, Marie told Pierre not to turn on any lights. There, on the benches in tiny glass containers glowed even tinier specks of radium, just 0.1 gram or 0.0035 ounces.

The "laboratory" shed, from history.aip.org

They were too proud to patent the purification process, and they spent the next few years learning more about radium's properties. They hated and feared the fame they'd gained and avoided going to any parties held in their honor. Pure scientists are that way. Pierre died in a traffic accident in 1906, leaving a very distraught Marie to continue studies on radioactivity. 

Scientists and doctors learned that exposure to radium destroyed certain tumors, and the treatment called Curietherapy was born. This prompted a great deal of work to produce more radium. When World War I broke out, Marie took to the battlefields with her daughter Marie in her "little Curie" car to use a Roentgen device to take X-rays and provide on-the-spot diagnosis of injuries. In doing so, she taught many nurses how to take X-rays and treated a million wounded soldiers. Before that, she'd never even learned to drive a car!

 

Marie Curie in her wartime "little Curie" (from The Radioactive Woman: Marie Curie's WWI Legacy)

Marie gave speeches around the world, despite her shyness, and she won awards from many countries. She died on July 4, 1934 after suffering from aplastic anemia, probably caused by exposure to X-rays.

Mysterious ticking sound leads scientists to creature with green bones in Colombia

Link to original article

This article from the Miami Herald talks about the discovery of a particular green frog Nymphargus pijao in the village of Pijao, Columbia. It is one of a species of glassfrogs. No, they aren't made of glass, but parts of their bodies are as clear as glass or nearly so. This one has a transparent stomach.

Photo from the article

Skin is thought to have evolved to protect the body of animals, from heat loss or from the effects of sunlight, as well as to provide some sort of distinctive coloring to identify the animal as male or female, or to camouflage it against predator attacks. Why would it be clear, and how does this happen? What other animals are transparent? And is it just their skin that is see-through?

First of all, what is the difference between transparent and translucent? Transparent objects allow light to pass through them completely; the light isn't reflected, absorbed, scattered or refracted (bent). But translucent ones only partially permit light to pass through.  Glass, swimming goggles, and clean water are transparent, but jelly, lampshades, and stained glass are translucent, for example.

Here are some examples of animals that are either transparent or translucent.

• Transparent Amazonian fish (Cyanogaster noctivaga)
• Golden tortoise beetle (Charidotella sexpunctata)
• Sea angels (Gymnosomata)
• Barton Springs salamander (Eurycea sosorum)
• Translucent tadpoles
• Larval squid
• Glasswinged butterfly (Greta oto), close-up dragonfly
• Transparent juvenile surgeonfish
• European eel larvae
• Juvenile octopus
• Translucent snail
• Transparent immortal jellyfish
• Juvenile cowfish
• Ghost shrimp
• Deep sea anglerfish
• Japanese icefish (shirauo), Antarctic ice fish
• Translucent pharaoh ants (Monomorium pharaonis)
• Yellow amycine jumping spider

If you look at the list, you will notice right away that most of the animals live in water. It has been easier for evolution to generate these clear creatures because water doesn’t scatter or refract (bend) light as much as air does. Being transparent in water is a great advantage to hide from predators. Put a glass in water , and you’ll notice how difficult it is to see it compared to being in air. (Some magicians rely on this quality to hide objects in plain view.)

Also, many of the examples are for young creatures (tadpoles, juveniles, larvae). Being see-through is a great defense against predators, especially when they are small and defenseless. If they can't see you very well, they can't eat you. But even adults benefit from this invisibility, too.

Sometimes the whole animal is transparent or translucent, but other times only part of it is, like the Nymphargus pilao frog above, or the Amazonian transparent fish Cyanogaster noctivaga (below).

photo from SciNews

The environment can cause changes so that the animal loses transparency. Ghost shrimp respond to an increase in temperature or salt concentration, and their blood-like material travels to the spaces between muscles, which shows up as white color. It can also happen with old age or when they are about to molt.

clear (left) and white (right) ghost shrimp

So, what is it about the cells through thick bodies of animals that allow light to pass through? Cells normally don't have many pigments in them (like melanin in skin). Nails and lenses of the eye have material called crystallin in the cells to make them clear. Organic molecules in cells have no pigment at all (which is why you see bottles of alcohol or benzene that are clear liquids).

Larvae of eel surgeonfish store energy in the form of a sugary chemical called GAG, which is mostly water, so light passed through easily.

Eel larva from Wikipedia

In the Antarctic icefish, there are no red blood cells. In the blood and other tissues is an anti-freeze protein to prevent the body from collecting ice, and this also reduces the scattering of light.

Photo from The Blood Project

Some mollusks like squids have direct control over cells. Nerve signals sent to pigment cells called iridophores cause a protein inside called reflectin to clump together, and enough of that changes how thick the cell membrane is. When it is thin enough, it stops reflecting light and lets light pass through. Scientists have genetically changed human cells in the lab to do this, too, and it will hopefully help watch certain processes more easily inside cells.

For glasswing butterflies, you can see how the cells are arranged to permit light to pass through. The fuzzy feeling of a wing comes from the little hairs you see below in picture b. Between the hairs at a higher magnification, you can see cell structures called nanopillars which point upward. The left picture is a view from the top, but the c picture is at an angle, so you can see how the nanopillars are arranged. That pattern lets light through. The colored parts of the wing are much more randomly arranged, and light is blocked.

Photos from article in Nature Communications

Nanopillar research is more than just cool stuff to read through a wing. Eye implants made of similar materials allow doctors to measure eye pressure in patients with glaucoma. Without the implants, the optical reader has to be held at a right angle to the eye, which is difficult. Nanopillar implants let the reader scan at any angle.

A good follow-up article on what makes animals cells transparent. "Tissue Transparency In Vivo"

Here's some Japanese research showing how chemicals added to brain tissues make them more transparent for better studying.

James Webb Space Telescope studies mysterious exoplanet with a possible watery past

Link to article May 13, 2023 from space.com

NASA's $10 billion James Webb Space Telescope (JWST) has just detected a "mini-Neptune" planet GJ 1214 b about 48 light-years away. It's the most common type of planet we know. This one is not the first that has been seen, but it's the first showing an atmosphere, and the second mini-Neptune whose mass and radius were calculated.

Illustration of Earth, GJ 1214 b, and Neptune (Aldaron/Wikimedia Comons/CC BY-SA 3.0)

What do we mean by "mini-Neptune" anyway? The Neptune in our solar system is the eighth planet from our sun and is almost 58 times the Earth's volume. It has a rocky core surrounded by a mix of water, ammonia, and methane ice in a kind of slush. Mini-Neptunes are built of similar materials, but the have a radius about 1.7 and 3.9 times that of Earth's. Our Neptune is blue, but that's not because of water oceans; in fact, nobody knows why is is blue.

Neptune's core, slushy mantle, and thick atmosphere (image from space.com)

GJ 1214 b and Neptune are classified as ice giants, while Jupiter and Saturn are gas giants. But the term "ice" is not what you might think. The gases in Jupiter and Saturn (hydrogen, helium) are cold, but they have not frozen. Different gases (ammonia, water vapor, methane) make up the exterior of Neptune planets, and they do freeze, so scientists group the water ice, methane ice, and ammonia ice as just "ice". Ice giants are also sometimes known as "super Earths".

The JWST was launched on Christmas Day, 2021 and reached its final orbiting point in January 2022. The pictures below show it during construction (left, to provide scale with people) and an image of it after it opened its main reflector.

Pictures from Wikipedia

Not much was known if GJ 1214 b for ten years. It has a dense hazy atmosphere, and it was the only planet to circle its sun, which it does in about 1.6 days (Earth days, that is). That made it convenient for  the JWST. Better equipped than the Hubble to look at objects with infrared light, the JWST watched as GJ1214 b revolved around its start completely instead of just getting a glance as it passed in front of the star. The JWST used the infrared measurements to make a "heat map" of the entire planet.

heat map from Nature

This new mini-Neptune spins around its star like the Moon goes around the Earth, with only one side facing inward. So, on the sunlit side are as high as 279 degrees C, and on the dark side it goes down to 65 degrees C.

Because GJ 1214 b does not have much hydrogen or helium in its atmosphere, unlike Neptune, it is thought that maybe it lost those gases into space. The alternative is that it never had them when it formed, but nobody knows for certain. If it lost hydrogen or helium, then that explains why these types of planets are sometimes called "transition planets".

For more on the JWST, go to this link.

For more on Neptune, go to this link.

 Hideyo Noguchi, Hardworking, Humble, Hometown Hero

The commonest paper currency in Japan has the face of a scientist of humble beginnings, yet Hideyo Noguchi is one of Japan's all-time heroes. Being the first scientist to have his face on Japanese money is just a small token of appreciation.

He was born Seisaku Noguchi on November 9, 1876 in a small village in the center of Fukushima Prefecture (the one hit by Japan's 311 earthquake, tsunami, and nuclear power plant leak, March 11, 2011). His father was a poor farmer, and his mother was virtually illiterate. Before the age of two, Noguchi fell onto a fireplace and badly burned his left hand causing it to be deformed with fused fingers. His teacher and classmates pitched in to send him to a hospital at ate 8 for hand surgery, which impressed Noguchi about medicine. Later, at 16 he had another operation which improved his hand even more. Finally, at 21 he had a third operation. (Most pictures I have found of him show him hiding that hand even after reconstructive surgery.) An elementary school test examiner recognized Noguchi's hardworking studious nature and good graded even though his family couldn't buy new textbooks, so he looked after Noguchi and his family for several years. 

After graduating from high school with honors, he joined Kaiyo Hospital as a medical student and studied medical science, English, and French for 3 years. He read foreign medical books by using a dictionary. In 1896, Noguchi traveled to Tokyo to take the National Medical Practitioners Qualifying Examination to become a doctor. This took him a full year, taking each half a year apart. During that time, he worked as a janitor to pay the bills. Before he struck out from his home in northern Japan, though, he showed his devotion to passing the exam by carving a statement on a post outside his home: "I shall not return to my native home if I do not achieve my objective." Most applicants for the doctor's exam need several years to pass, but Noguchi's studies paid off and he succeeded in less time.

Seisaku Noguchi, 1896 (from Japan Cabinet Office)

Noguchi struggled to find clinical work that first year because of his deformed left hand, but he persisted. He then read a novel Portraits of Contemporary Students, whose main character, "Seisaku Nonoguchi," was a failed immoral medical student (a drinker and woman chaser). Seisaku Noguchi thought deeply about this and his difficulty in finding work, so he asked his old teacher for advice. As a result, he went home and changed his name from Seisaku to Hideyo, which means "superior man of the world" just to show his determination to help the citizens of Japan as a medical researcher. After that, he found work at three locations. For a month he lectured at the Takayama Dental School, then Juntendo Hospital and Kitasato Institute of Infectious Diseases (both in Tokyo), and finally the Yokohama Port Quarantine Station.

At the Kitasato Institute, he met a medical researcher Simon Flexner from the University of Pennsylvania who was traveling abroad. Noguchi helped as a translator/interpreter and began to dream of working internationally. As a quarantine officer in Yokohama, he was commended for his discovery of a person who had the plague, a very dangerous disease to the public. After six months, he was sent to China to work for 2 months for the International Sanitary Board as a health officer. His excellent English and rapid learning of Chinese earned him great praise, and this began his international experience. 

quarantine officer, 1899 (photo from Japan Cabinet Office)

An eager and excited Hideyo Noguchi then embarked on a sudden trip to the University of Pennsylvania where he hoped to engage in research. He began work in the Department of Pathology as Flexner's lab assistant studying snake venoms. 

Noguchi and Flexner at the University of Pennsylvania, Philadelphia (photos from Japan Cabinet Office)

Three years later, he got a fellowship grant to study bacteria in Copenhagen under Thorvald Madsen. Specifically, he learned about blood serum changes when people are infected, and how to use it to treat other patients. This was enough after just one year to earn him a job back in the U.S. with Flexner again, in a new research facility, the Rockefeller Institute for Medical Research. Small town Hideyo Noguchi's career as a researcher in bacterial infections was now officially off to a start in 1904 at age 27! He even got a master's degree there in 1908. Three years later he got married to an American Mary Dardis.

In Pennsylvania, with his background in blood serum detection of infectious agents, Noguchi succeeded in growing the curly bacterium called Treponema pallidum from the brain of a patient with syphilis. People had known it caused syphilis only since 1905, but its diagnosis was difficult. He published a book on the topic of identifying this bacterium, made international lectures, and was even nominated for the Nobel (but never got it). However, he did win the Imperial Prize of the Japan Academy in 1915. In addition, the King of Spain and the King of Denmark awarded him with medals for his lectures and research.

Manual on detecting syphilis

Noguchi worked on many other diseases, too, although he made some mistakes in identifying the causes. Nevertheless, he was one of very few Japanese researchers who lived and worked outside of Japan. His research took him to Central and South America to study yellow fever, Oroya fever, poliomyelitis and trachoma.

Landing in Ecuador (photo from the Japan Cabinet Office)

In 1914, he got his PhD from Tokyo Imperial University despite all of the research and traveling he was doing.

Unsurprisingly, his home life with Mary was sporadic, and he kept the marriage secret from most people. He took work home, literally, and kept bacterial cultures in their refrigerator and worked on the kitchen table. Mary loved him, though, and broke him of his habit to wear old, oversized clothes. She even read novels to him while he worked at home. His eagerness to constantly do research despite getting only 3-4 hours of sleep per night also showed some sloppiness in his work. An enlarged heart and diabetes were two illnesses he suffered from, and in 1917 a typhoid infection almost killed him.

While studying the cause of yellow fever, he thought it was the same kind of spiral bacteria that caused syphilis. That was proven false, though, and it might have been one reason he accepted the opportunity to travel to Ghana, Africa to study yellow fever. His colleague Dr. Adrian Stokes died of it before Noguchi left the U.S. in 1927, so the Rockefeller Institute asked him to go. Within 6 months, he had confirmed yellow fever was caused by a virus, but he caught the disease twice himself, and shortly before he was to return to America, he died from it in 1928.

Noguchi in his lab (photo from Japanese government)

Subsequently, his home in Fukushima has been made into an elaborate museum dedicated to his life and exploits. It even has an animatronic figure of him speaking. In his life, he published 200 papers, and his colleagues marveled at his energy and lack of sleep, calling him the "human dynamo". Hideyo (superior man of the world) Noguchi is revered by many in Japan even to this day.

Museum home and animatronic display (photos from Nippon.com)