Vorticella Facts

Over hundred different species of vorticella, a protist (protozoan) are listed under the phyllum ciliophora and kingdom protoctista. Each vorticella cell is a stalked ciliate which looks like an inverted bell. There are some other genera which resemble vorticella, such as carchesium, but they are different in structure. Following vorticella facts will help you understand their classification and it will also help you differentiate them from other similar genera.

Interesting Facts about Vorticella
Vorticella are sessile (permanently attached to a substrate) organisms. However, young ones can be seen free-swimming. Adults also swim freely if their stalks are cut or if they have to detach themselves from the substrate due to unfavorable conditions. It is wonderful to observe how adult vorticella is attached to substrates with stalks.

One of the most amazing vorticella facts is that its peduncle (stalk) is capable of contracting and the contraction is caused by the 'spasmoneme', the wavy filament that is present inside the peduncle. The filament shortens when stimulated and the stalk coils like a spring. Earlier, the filament was called 'myoneme' (muscular filament), before it had been discovered that the chemical system that administers the contraction of the spasmoneme is different from the system which a true muscular fiber uses.

The spasmoneme consists of three cellular membranes, an extracellular matrix and an outer sheath. Coiling of the stalk upon contraction is believed to be a defense mechanism to protect itself from environmental hazards such as turbulent water. Contractions also help them to capture food. Vorticella are heterotrophic organisms.

It can be observed that some microfibers of the spasmoneme enter the body of the vorticella and are perhaps part of the system that retracts the apical disc and the ciliated ring. The spiral ring has 3 rows (membranelles) of cilia which offer great mobility causing an eddy or 'vortex' in the water, (therefore the name vorticella) that attracts the food towards the small buccal funnel. They eat bacteria and very small flagellates. The main purpose of the cilia at the top seems to be sweeping food down into the gullet.

They can be sometimes noticed in clusters that form a tiny jelly-like mass just visible to the naked eye. But each vorticella has its own stalk and therefore it can detach from the cluster at any time, usually by achieving the state of a telotroch (free daughter after splitting of the parent) when environmental conditions are unfavorable. For instance, if food supplies are scarce then they need to find a new location. Studying microorganisms in pond water is really very fascinating.

They are mentioned as peritrichs, meaning that their cilia are concentrated around the mouth end, but nowhere else on the body. When vorticella needs to move, temporary cilia will form around the body. One of the most interesting vorticella facts is that once the organism has grounded itself (attached itself to any material), these cilia will disappear!

Size
While considering vorticella size, size of the bell and size of the stalk is to be considered separately. Usually, the 'bell' is up to 150 µm, with stalk up to 1 mm.

Habitat
Vorticella, placed among the peritrichs, are found easily in freshwater ponds and streams. Vorticella, a genus of protozoa, usually fix themselves firm to small particles of material. However they can also be seen swimming freely. They are the unicellular aquatic organisms which attach themselves to plant detritus, rocks, algae or animals. They are often seen attached to algae or plants or to the leaves and roots of the aquatic plants or they are found on crustaceans, especially crabs or on shells of gastropod molluscs.

Reproduction
Vorticella reproduce via binary fission. The process of vorticella division is called budding. They undergo longitudinal fission. As they split along the longitudinal axis into two halves, one daughter holds the stalk and the other half freely swims away. The free daughter becomes a telotroch, which swims until it finds suitable substrate to fix and develop its own stalk. They reproduce by fission, which is also called 'cell division'.

They are also capable of reproducing by conjugation. Conjugation is in fact a form of sexual reproduction where two vorticella come together and attach at the oral groove and exchange DNA.

The 'vorticella' are attractive, quite abundant, common and easy to observe. A vorticella was the first protozoan described by Anthony van Leeuwenhoek, father of microscopy. They are difficult to prepare if you want to study their cytology. It requires time and opportunity to be able to observe all the processes in the life of vorticella.