What makes an amoeba

When the amoeba digests large amounts of diatoms, you can even see the oil droplets inside the cell of amoeba. This is because some diatoms are tiny oil producers! Some large amoebas contain bacteria and small green algae inside their cytoplasm. For example, green algae live inside can provide additional energy to their host the amoeba , making the amoeba can live in nutrient-poor environments.

The answer is no. The family of Amoebas comprises very diverse members with over 15, described species. Although they all share one characteristic — moving by pseudopods, they can be totally different in shapes and sizes. B Thecamoeba. The body of Thecamoeba often forms a wrinkled cornucopia shape. C Vampyrella got its name by the way it feeds.

Vampyrella sticks to its victims usually algae , makes a large hole in the algal cell wall and sucks the protoplast of the algae. Credit: Pelomyxa and Thecamoeba — eol. Amoebas can be divided into two major groups: naked amoeboids subclass: Gymnamoebae and shelled amoeboids subclass: Testacea. These Amoebas with soft, gel-like cell bodies, like Amoeba proteus, Pelomyxa, Thecamoeba, and Vampyrella , are all naked amoeboids.

Some shelled Amoebas make the tests entirely by themselves and the materials could be organics, siliceous containing silica or calcareous containing calcium carbonate components produced by the Amoebas. These tests are called autogenic tests. Some shelled Amoebas prepare their tests by collecting particles of sediment around them and glue these mineral particles together by slime ingredients secreted from the cells.

These tests are called xenogenic tests. Credit: Frank Fox on wiki. These shelled amoebas can be collected with the same methods as naked amoebas. However, since the tests could easily break, you have to be careful when examining them under the microscope.

The weight of coverslip may crash the tests of shelled amoebas. Use the microscopic slides with a single concave or add some dots of Vaseline under the corners of the coverslip to provide more space for these creatures.

The Greek meaning describes this microbe as the Sea God Proteus that has a constantly changing shape. Amoebas belong to the Kingdom of the protists a protist is any eukaryotic organism that is not an animal, plant, or fungus.

However, in terms of classification, the position of amoebas just like their shape — consistently changing. In the early days, when the microscopy was the only way to characterize the microorganisms, amoebas were classified as Phylum Sarcodina with several other species like Heliozoa.

Once the molecular phylogenetics classify a species by its genetic materials was introduced, amoebas are now in Phylum Amoebozoa. We have however to keep in mind that the classification of the protists is presently much debated. Heliozoa is commonly known as sun-animalcules.

Unfortunately, it is true. Although most amoebas are harmless to human beings, some rare species can be parasitic inside the human body. Naegleria fowleri has two flagella like tails so it can swim in the water. Most of the time, Naegleria fowleri is free-living and eats bacteria.

In some very rare cases, Naegleria fowleri can be inhaled through the nose and travels to the brain, causing a deadly disease called Naegleriasis. Actually, a case of brain-eating amoeba has been confirmed in the Tampa area, according to the Florida Department of Health on July 6, Related news please visit here. At a certain stage of its life circle, the Naegleria fowleri can swim by two flagella.

Amoeba Proteus , Euglena , Tardigrade , and Paramecium caudatum are the most frequently studied microlife creatures in classrooms and laboratories. Pingback: What is an amoeba? Biology Questions and Answers. The ectoplasm is the thin, transparent, somewhat rigid portion. The differing consistencies of endoplasm and ectoplasm aid in the formation of pseudopod. The amoeba cell may form a single dominant pseudopod, especially when crawling or several pseudopods at once when they are freely floating.

Typically, there is a single nucleus that contains most of the DNA. Another prominent cytoplasmic structure is contractile vacuole. The major function of contractile vacuole in amoeba is for osmoregulation. It regulates osmotic pressures within the cell. It does so by filling itself with excess cytoplasmic water diastole.

Then, it fuses with the cell membrane to release the content outside by a quick contraction systole. Amoeba reproduction is by binary fission, a type of asexual reproduction incorporating mitosis and cytokinesis. Sexual reproduction e. In older classification system, Amoeba is classified under the subphylum Sarcodina , a taxonomic group within the phylum Sarcomastigophora.

Members of this subphylum are characterized by being single-celled and their ability to move by protoplasmic flow or by pseudopod. However, molecular phylogenetic studies implicate that Sarcodina is not a monophyletic group, meaning its members do not have a common descent, and as such cannot be considered as a single group. Free-living species of the Amoeba genus are found in freshwater and soil habitats. They are major predators of bacterial populations.

It is a large protist as its length may reach up to 2 mm. It is non-pathogenic as there has been no known Amoeba proteus disease in humans and other animals. Some amoeba-like protists, though, are opportunistic pathogens. Given the opportunity, they may live as a parasite inside a host and cause disease. One of the medically-important amoebas is the Entamoeba histolytica. This species causes entamoebiasis and amebic dysentery to its human and other primate hosts.

It forms a cyst that can be transmitted through ingestion of infected water or food. They can switch back and forth between an amoeba form and some other form. Like bacteria, amoebas have just one cell. But there the similarity ends. For one thing, amoebas are eukaryotic Yoo-kair-ee-AH-tik.

Bacteria have no nucleus. In some ways, amoebas are more similar to human cells than to bacteria. Also unlike bacteria, which hold their shape, shell-free amoebas look like blobs. Their structure changes a lot, Lahr says. Their blobbiness can come in handy. Amoebas move by using bulging parts called pseudopodia Soo-doh-POH-dee-uh.

An amoeba can reach out and grab some surface with a pseudopod, using it to crawl forward. Pseudopodia also help amoebas eat. That allows this microbe to swallow bacteria, fungal cells, algae — even small worms. Some amoebas eat human cells, causing sickness. Still, some species can be lethal. The disease they cause kills tens of thousands of people each year, mostly in areas that lack clean water or sewer systems.

But if it gets inside the nose, it can travel to the brain where it feasts on brain cells. This infection is usually deadly.

The good news: Scientists know of only 34 U. A scientist named Sebastian Hess recently discovered the tricks some amoebas use to eat. He studies eukaryotic microbes in Canada at Dalhousie University. Hess has loved watching tiny critters through a microscope since he was a kid. Ten years ago, Hess punched through the ice of a frozen pond in Germany.

He collected a sample of water and took it back to his lab. Through the microscope, he saw something odd. Green spheres were wiggling like tiny bubbles inside strands of green algae. So Hess mixed algae containing the green balls with other algae. The wiggling spheres popped out of the algae and started swimming. Shortly afterward, they invaded other algal strands.

That means they can switch between two forms. In one form, they swim or glide using tail-like structures called flagella Fluh-JEH-luh. When the swimmers find food, they transform into amoebas. Their shape becomes less rigid. Instead of swimming, they now begin crawling along some surface. Through the microscope, Hess watched one of these amoebas cut a hole in an algal cell. The amoeba squeezed inside. Afterward, the amoeba divided and made copies of itself.

Those were the wiggling green spheres that Hess had seen earlier. The new amoebas punched more holes in the algal cell. Some invaded the neighboring cell in the algal strand. These cells are genetically identical. Some amoeba also reproduce by multiple fission. In multiple fission, the amoeba secretes a three-layered wall of cells that harden around its body. This layer, known as a cyst, protects the amoeba when conditions become harsh.

Protected in the cyst, the nucleus divides several times. This nuclear division is followed by the division of the cytoplasm for the same number of times. The result of multiple fission is the production of several daughter cells that are released once conditions become favorable again and the cyst ruptures.

In some cases, amoebas also reproduce by producing spores. Some amoeba are parasitic and cause serious illness and even death in humans. Entamoeba histolytica cause amebiasis, a condition resulting in diarrhea and stomach pain.

These microbes also cause amebic dysentery, a severe form of amebiasis. Entamoeba histolytica travel through the digestive system and inhabit the large intestines. In rare cases, they can enter the bloodstream and infect the liver or brain. Another type of amoeba, Naegleria fowleri , causes the brain disease amoebic meningoencephalitis. Also known as brain-eating amoeba, these organisms typically inhabit warm lakes, ponds, soil, and untreated pools.

The microbes feed on brain matter by releasing enzymes that dissolve brain tissue. Acanthamoeba cause the disease Acanthamoeba keratitis. This disease results from an infection of the cornea of the eye. Acanthamoeba keratitis can cause eye pain, vision problems, and may result in blindness if left untreated. Individuals who wear contact lenses most often experience this type of infection. Contact lenses can become contaminated with Acanthamoeba if they are not properly disinfected and stored, or if worn while showering or swimming.

To reduce the risk of developing Acanthamoeba keratitis, the CDC recommends that you properly wash and dry your hands before handling contact lenses, clean or replace lenses when needed, and store lenses in a sterile solution.