by Micro World Lab staff member Nancy Locquet-Absillis
Munching away, a very hungry, microscopic worm-like organism slides steadily around in the murky green algae, trapped between a coverslip and a microscope slide. It is named Aeolosoma (pronounced e’ o lo so’ ma) and it, like most microscopic creatures in our lab, spends most of its time looking for food.
Can you see why this worm is also known as a bristle worm? Large bristle-like hairs called setae (see-t-A) appear to serve as legs and help the Aeolosoma to move around in its environment.
Most Aeolosoma have been commonly found in artificial ecosystems such as sludge digesters, but ours usually hang out in debris at the bottom of the pond water containers.
Very little is known about Aeolosoma species living in nature. We do know that species living in waste disposal systems are capable of processing large amounts of raw sewage into sludge as they digest decaying organic matter and prey on microorganisms such as bacteria and protozoans.
You could compare this microscopic bristle worm with its relative, the earthworm. Both play an important role as decomposers. By digesting detritus, they break down dead organic matter into smaller pieces allowing bacteria and other organisms to further break it down, releasing nutrients in the process.
It’s hard to see, but Aeolosoma have segmented bodies. Most Aeolosoma have about 17 segments but some species have more. It seems that, apart from the head and the first segment behind the head, each segment has 2 sets of setae at either side of its body.
Because Aeolosoma are so big, it’s easy to spot these “giant” worms at a magnification of 4x (this means that the image seen on the EVOS microscope screen is 65x magnified compared to real life).
If you look closely, you can see red-colored pigments in dot-like structures called globules (gland cells) in the outer layer of cells called epidermis. The function of these colored epidermal gland cells is unknown, but since the color of these gland cells can vary from red to brown, green, blue-green, yellow or colorless, it’s an easy tool to identify species.
Its U-shaped mouth is clearly visible in the picture above; it is located underneath its big, rounded, oval shaped head and acts as a very efficient vacuum cleaner, picking up microscopic plants and microorganisms as it meanders through algae and decaying matter.
Tiny little hairs called cilia on the fringes of its mouth are constantly moving, creating the vacuum effect.
Because of the transparency of the Aeolosoma, you can clearly see how the food particles are being digested, bit by bit. The food particles move through its digestive system by the contraction and relaxation of the muscles until it leaves the 1 to 2 mm long body (peristalsis movement).
Some Aeolosoma are excellent swimmers and move smoothly through clear patches of water under the microscope but most of the time, you’ll see them “snuffeling” for food. With an unstoppable appetite, we just consider them the ever-so-very-hungry Aeolosoma.
We are kicking off Insect Thursday in the Naturalist Center starting at 6:30 pm on Thursday, August 28, 2014, when we will have Olivia Evangelista from the Museu de Zoologis da Universidade de Sao Paulo, Brazil, discussing treehoppers. Dr Evangelista is a visiting postdoc in the genomics research lab in the Nature Research Center. She studies Membracidae, a group of true bugs which exhibits a vast diversity of crazy ornaments.
Treehoppers are a type of small winged insect. There are thousands of species of treehoppers, and they are widely distributed around the world. Treehoppers are of interest mainly because of their fantastic shapes. The prothorax, the body region between the head and the wings, is variously shaped. It often grows up and back over the body and wings, forming bulbs, spines, crescents, or circles. Treehoppers feed on plant juices and lay their eggs in plant tissues.Some treehoppers are called thorn bugs because the resting insects looks like thorns. They range in color from green and blue to bronze and are often marked with spots or stripes. Many treehoppers secrete honeydew, a sweet by-product of digestion. Most of these sap-sucking insects occur in the tropics.
Drop by and talk to our expert about the weird and wonderful world of treehoppers!
For more information contact Cindy Lincoln, coordinator of the Naturalist Center: email@example.com.
by the Micro World Investigate Lab staff and volunteers:
Every state has a state bird, but North Carolina’s also got a wonderful candidate for state protist: Paramecium. It looks a bit like a foot with a tarheel, a great match for the Tar Heel State.
According to Rice University’s Experimental Biosciences Department, a paramecium is pretty large for a protist. It measures roughly half a micrometer in length, about one-sixteenth the length of an eyelash.
All paramecium are entirely covered in cilia, hairlike organs. They beat all at once to propel the paramecium forward, or wherever it wants to go.
Paramecium are well-known for hasty retreats. MicrobeWiki says that paramecium have been seen rotating up to 360 degrees to escape from predators.
Though it probably prefers flight over fight, a paramecium is definitely not defenseless. This protist has spines—trichocysts—lying right underneath its outer cell membrane. If a situation gets too dicey, it shoots them at predators to stave them off.
Paramecium, like humans, is a heterotroph, a hearty consumer of both plant and animal life.
Because a paramecium is clear, we can easily see what it’s eaten just by looking at it. This particular one seen above, seems to have been eating a lot of microscopic salad: it’s full of green plant matter from algae. That makes complete sense, given the paramecium’s living conditions. They’re lucky enough to be surrounded by their food 24/7. That’s the murky green stuff in the picture.
Paramecium have a mouth-like area called an oral groove running along the upper side of their bodies. It’s lined with fast-moving cilia that work like a conveyer belt to move food down into a paramecium’s body.
Instead of making use of a permanent stomach, a paramecium feeds via a process called phagocytosis. When it takes up food, the paramecium makes itself a temporary “stomach” out of its cell membrane. This vesicle encapsulates the food while the paramecium’s extremely small organs—organelles—pump in digestive enzymes to break down the food product.
The paramecium here are exploring, maybe even going out to dinner for some ubiquitous algae.
Sometimes, certain algae live in the body of a paramecium and provide food to it as a sort of “rent.” That’s a symbiotic relationship, one where both involved species benefit from the arrangement. The bacteria that live in our digestive tracts are part of a symbiotic relationship that humans are part of. The gut bacteria get a place to live, and a share of the food we digest. We can’t digest our food without them, so we benefit, too.
By Nancy Locquet-Absillis
Life in a drop of pond water doesn’t seem to be very exciting right? Well, this is what happened one sunny morning in the Micro World Investigate Lab…
We took a drop of pond water, placed it under the EVOS microscope and tried to look for interesting microorganisms when suddenly, a familiar protozoa came into view.
It was one of those bulb-like rotifers (probably Trichocerca), using its spurs (toes) to anchor itself to substrate while drawing in gulps of water containing food particles. As there are about 2200 species of rotifers described, it’s difficult to make a positive identification of this particular one.
Moving seemed easy, it just let go of the sediment it was anchored to and used its adhesive gland, located above the foot, to hold on to some sediment a few microns away. Its mastax (grinding tooth) was pulsing in its body like a heart.
On its path was another rotifer minding its own business, being firmly attached to some sediment. Its head (called corona) showed 2 crown-shaped rotating disks. If you looked closely, you could even see the cilia (small hairs) sway. Since these cilia move so fast, it gives the impression that the corona (crown) is rotating. That’s probably how it got its name … rotifer.
Anyway … when these 2 different rotifers met, an interesting event happened. The bulb-like rotifer started to attack the body of the attached rotifer. Trying to avoid the ferocious attack, the “crown type” rotifer (Bdelloid rotifer) crunched and collapsed as it was protecting its corona inside its body.
In an attempt to break up the argument, we tapped on the wet mount slide with a pencil but that didn’t change the bulb rotifer’s mind. Why the attack? Did she want that spot? Was she so hungry she started attacking another rotifer?
According to Dr. Peter Starkweather from the University of Nevada Las Vegas, most rotifers are females and they are the ones feeding constantly. These multicellular organisms are made up of about 1000 cells and they have a complete digestive system.
Female rotifers can be classified into three groups by the way they eat:
- Filter feeders take in volumes of water and filter out food particles.
- “Graspers” use their coronas to hold on to their food and chew it up with their trophies (a jaw like structure in the mastax region).
- Capture feeders trap their prey with their coronas before they devour it.
Here are two videos of a feeding rotifer in action:
Male rotifers don’t eat—they only live for a few hours and don’t even have the structures necessary to eat— so the ones we saw attacking were females.
It was clear that the cilia of the Bdelloid rotifer (crown-type) were creating a circular current of water drawing food particles into its mouth. She seemed to be filtering the water for algae, small single celled organisms (organism that consist of only one cell), debris, and bacteria while the bulb-like rotifer was showing some signs of cannibalism.
Several attempts to save the Bdelloid rotifer (crown-type) failed and we almost felt sorry for her until all of a sudden their roles were reversed: the bulb-like rotifer got caught in the current created by the cilia of the Bdelloid rotifer and it was spinning out of control locked by the water flow. Was this rotifer revenge?
This argument ended with the bulb-like rotifer retreating in search of some “quiet waters” while the “crowned one” emerged victorious.
Just a quick view of the Title I Night event at the Museum, as it looked in our Micro World iLab. It was a busy night with LOTS of parents and students visiting our lab and participating in lab table activities.
Here is another entry in our “Catch of the Day” series, by Nancy Locquet-Absillis
iLabs: “Catch Of The Day!” — Water bear, water bear, how DO you survive?
Look how cuddly! A rather clumsy, barrel-shaped microorganism moves like a bear on the slide we’ve placed under the microscope. Since its segmented body is transparent, you can see food in its stomach. With four pair of legs it’s clinging on to some substrate, which is usually moss or algae. The 8 stubby-looking legs are not segmented and seem to end in about 4 to 8 bear-like claws called discs. The discs are very flexible and can hold on firmly to algae, while the creature is searching for food.
The creature is known by a few names: water bear, moss piglet, or tardigrade, and it is a water-dwelling, segmented, 8-legged micro-animal.
What’s that, you say? There’s not a lot of food in a drop of pond water? On the contrary, the water bear is submerged in its food!
Its tube-like mouth has a special piercing device called a stylet to puncture through plants cells, algae or even small invertebrates. Once inside its prey, the stylet opens up so it will not pull out, and like a vampire, the water bear sucks up the cell content of plants and algae … or the body fluids of its victim/meal. It seems just a touch ferocious for such a cute-looking teddy-bear-like organism.
As small as it is (and that would be about 0.5 mm to 1.5 mm when they are full grown), it has a complete digestive system with esophagus, an intestine the size of its body, a very short rectum and anus. Some species only defecate, leaving the feces in its “shed.”
Molting is an elaborate process and takes about 5-10 days. Some staff members of the Micro World Investigate lab were so lucky to see it happen and they took a snapshot of this event. Look at this picture. You can clearly see how the body is separated from the shed when you look at the legs.
Water bears molt about 4 to 12 times during their 3 to 30 months of active lives. Since they lose their piercing mouthparts during molting, a tardigrade (a name given to this organism by Lazzaro Spallanzani in the late 1700s, which means “slow walker”) can’t eat until the molting process is finished.
One day, we were so fortunate to see eggs inside the shed of a water bear! About Thirteen eggs were deposited in this water bear’s shed. We haven’t seen the newly born hatchlings, since it take about 14 days for them to hatch and it’s simply impossible to keep them on the slide for that long.
The hatchlings are born with a complete set of cells. This means that all tardigrades from the same species, no matter how big they are, have the same amount of cells (which would be about 40,000 cells).
The newborn tardigrades are smaller than 0.05 mm. They don’t grow by cell division like we do; their individual cells increase in size as they grow bigger.
Scientists believe that they have survived all 5 mass extinctions, making them one of the oldest surviving organisms on this planet. Fossil records show that they have been living on Earth some 530 million years!
How resilient is our superhero? Well, they survived the following situations:
- They were exposed to extreme high temperatures for a few minutes (151°C; 304°F) and extreme cold (−200°C; -328 °F) for a few days and survived! Even -272°C for a few minutes didn’t seem to have an impact on them.
- Freezing and/or thawing conditions didn’t bother them.
- Lack of oxygen … they seem to be ok with it.
- Changes in salinity (changes in salt content of their environment) … not a problem.
- They can survive the vacuum and the solar radiation of outer space (1000 x the lethal dose for humans) for 10 days as well as extremely high pressure — up to 6,000 atmospheres, which is 6 times the water pressure in the deepest ocean trench.
- Ten years of extreme drought doesn’t seem to be a problem.
- Tardigrades can dry up completely and form a “tun” as they shrivel up into a little ball. They can be “revived” from this dead-like state once water is available. How can they possibly do this? They possess a special sugar called trehalose which replaces the water in its body and preserves the body cells.
- They also survived being exposed to environmental toxins (chemicals such as boiling alcohol), although these lab tests still need to be confirmed.
It’s hard to believe that these amazing creatures have survived all this! Under normal circumstances they would only live for 1 year!
Would you like to see them in action? Come and visit the Micro World Investigate Lab.
While you’re there, try to find our blue water bear!
Here is the final installment on the creating of the Pandemic Class, by our intern, Megan Polzin:
iLabs: Teaching Middle School Students About Pandemics
SUCCESS!! Before I go over how the class went, I did make two more last minute changes to the class. The first was the addition of an 8.5’’ x 11’’ sheet of paper containing instructions for Set Up and How to Play. This information was originally going to be on a board at the front of the class, but due to my large handwriting, I was not able to fit it all. These pages were laminated and one copy was given to each group.
The second change I made was creating a Student Version of the PowerPoint. To do this, I eliminated important words from every slide and replaced them with blank underlined spaces. As I progress through the PowerPoint , the students fill in the blanks. This way, the students can take notes, have the links to the videos, and retain the information better!
Now on to how the class went… With everything set up and ready to go, there was nothing left to do but wait. The day before my class, I had the opportunity to meet the group of students and was excited to learn that they were attentive, asked many questions, and seemed genuinely interested in the subject of epidemiology!
After welcoming the students and introducing myself, I gave a brief synopsis of the class and started to go through the PowerPoint. It took them about ten minutes to warm up, but once I started on pathogens, vectors, and famous pandemics, they really got excited! We also discussed the basic definitions of epidemics and pandemics, the six stages of a pandemic, and vaccinations. I had only intended to spend thirty minutes on the PowerPoint, but with all of their amazing questions and comments, we spent close to an hour going over it! The pictures and videos were a huge hit, especially the videos from the show, Monsters Inside Me.
Next, we were on to the Pandemic Board Game. I had already set the board up under the ELMO camera and laid out all the game pieces including the additional board with the cut off parts. The large group was divided into four teams of four and each team was given a map card, role card, two reference cards, and a Set Up/How to Play card. I briefly went through the set up and explained how to play. This entire process took about fifteen minutes.
It took about one round for them to get the hang of it, but after that, they were absolutely fantastic! They were running between tables, exchanging ideas, and making brilliant moves! I was there to help them communicate with one another and give them several tips. Despite the game being challenging, they won with time left to spare!
After the class, the students told me that the class was awesome and that they were definitely buying the board game!
Overall, the class was a great success! Some things that I need to improve upon include the PowerPoint and the additional board. Important terms within the PowerPoint need to be bolded in order to draw attention to them as they are discussed.
Also, the additional board fell down on several occasions, so it needs to have some kind of support in the future. With these minute changes, the class will be even better!
I hope you have enjoyed reading about how I was assigned this project, the challenges I faced, how I dealt with them, and the end result of it all. I had a great time developing this project and was very lucky to have a great support team in the Micro World Investigate Lab who helped me conceptualize and refine my project to make it better!