Vampyrella

Vampire amoebae were first discovered in 1865 by Leon Cienkowski.[2] These amoebae were given the genus name Vampyrella due to their bright red colouration and their distinct feeding habits in which they perforate the cell wall of their host and draw out the inner contents of the cell, resembling that of folklore vampires.

At present, the vampyrellids are placed taxonomically in the cercozoan subphylum Endomyxa along with some soil dwelling taxa.[3] The clade within Endomyxa, Vampyrellida West, 1901, consists of the genera Theratomyxa, Platyreta, ‘Arachnula’, Leptophrys and Vampyrella.[3] Molecular sequence data exist for two families: Vampyrellidae and Leptophyridae. Frequently, Vampyrella is the only genus represented in Vampyrellidae.[3]

Most members of Vampyrella obligatorily alternate between a free living trophozoite stage and cyst stage.[1] In the trophozoite stage amoebae are free moving. Vampyrella is characterized by a roughly spherical shape,[1] however, it often changes shape[4] and becomes more ellipsoid or oblong.[5] A narrow, colourless ectoplasm at the edge of the cells can be very easily differentiated from the intensely coloured cell body.[6] The central body tends to vary between brick red, orange, reddish yellow, brown, or green.[4][6][7] Numerous long colourless pseudopodia extend in all directions giving trophozoites an isodiametric morphotype.[3] These pseudopodia can be as long as three times the diameter of the cell body and may be branched or unbranched.[6] The pseudopodia may accumulate in the direction in which the organism moves.[3] Shorter, slow moving, pin-like pseudopodia are projected and withdrawn very quickly from the cell body in addition to having longer pseudopodia.[4][5][6] Many vacuoles can sometimes be seen in the periphery of the organi [3] in addition to large, bubble-like non-contractile vacuoles.[6] Young trophozoites range from about 25-40µm, while mature trophozoites can reach to about 70µm.[3] Organisms tend to have multiple spherical nuclei with a central compact nucleolus.[1] Some species of Vampyrella have been observed to fuse with each other to form large plasmodia with the same structure and colouration as a single free-living cell. This has been observed when food has been limited.[3]

Vampyrellids can be found in a wide variety of habitats, soil, freshwater or marine, but members of Vampyrella tend to be found in freshwater environments.

Vampire amoebae of this genus are heterotrophic and feed on algae, notably Spirogyra [8] but also Chaetophora [1] or Mougeotia.[6]

When attacking, the Vampyrella organism flattens along the filament surface of its prey.[8] Upon attachment, the long pseudopodia disappear leaving only shorter pin-like pseudopodia.[8] A violent shock motion is usually observed as the Vampyrella attacks the algae.[5][6] Within minutes cell wall digestion initiates and the vampyrellid begins to swell as the contents of the algae are drained. The cell wall begins to bend inward due to a loss in turgor pressure causing adjacent cells of the algae to have greater pressure.[8] Upon fully digesting through the cell wall, a hole is created in the cell wall of the algae. The vampyrellid swells rapidly and the prey cell disarticulates. The protoplast of the prey is then sucked out into a food vacuole.[6][8] Remaining contents are then drawn out using pseudopodia.[6] The vampyrellid uses its pseudopodia to move from cell to cell repeating the process. Excess water absorbed from prey cells is removed by numerous small contractile vacuoles on the periphery of the organism, maintaining an only slightly increased size after each meal.[8] Vampyrella have been observed to both perforate the cell wall on the cell body as well as breaking the joints between algal cells to acquire the contents of the cell.[6]

Vampyrella have also shown to be selective of food type. Once in contact with filaments, it brings its body toward the filament. If the algae are rejected it will move on.[7] Among this selectivity, there is also differences among species within the genus. This has been observed as Vampyrella lateritia refuse to eat Oedogonium [6] while it will be eaten by Vampyrella pendula.[3]

Vampyrella are known to be algivorous predators which can be detrimental to the biomass of microalgal cultures.  Some green microalgae are capable of rapid growth and synthesize large quantities of protein, starch and lipid.  In addition, microalgae can be used in carbon capture, animal feeding, waste water bioremediation and biofuels. The main cause in loss of microalgal culture biomass is microbial contamination.[9]

• Vampyrella closterii
• Vampyrella incolor
• Vampyrella inermis
• Vampyrella lateritia
• Vampyrella multiformis
• Vampyrella pedata
• Vampyrella pendula
• Vampyrella ulothricus
• Vampyrella variabilis
• Vampyrella velata