Protozoa
(micron = 1/1000 of a millimetre)

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Ron Neumeyer

2002/11/03

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Bursaria sp.	The microscope has been focused to show the topography of the pellicle, a coating secreted over top the animal's cell membrane. The pellicle provides protection, support and movement. Its appearance and rigidity are characteristic for many species (this one is relatively flexible).
Paramecium bursaria	This image shows the tiny Chlorella sp. of algae that are frequently found inside the animal. It is a complex relationship, one that appears to be a mutually beneficial ("endosymbiotic").
Paramecium sp.	Viewed by means of transmitted, polarised light. The bright areas are a materials that rotate light from the substage polarizer so that it passes through the analyser. These are mostly starch and glycogen, two compounds used by protozoa to store energy. These animals have been under a coverslip for about 30 minutes so they are showing signs of stress (due to oxygen depravation and waste product build-up). This has stimulated the production of these compounds, especially starch.
Voriticella sp.	Viewed by means of transmitted, phase contrast illumination (a form of optical contrast enhancement). This is a highly differentiated single celled organism. Of special note is the long "stalk", which is attached to an out-of-view substrate. The stalk consists of a flexible tube containing a liquid and a contractlile cord (black strand). The bell-shaped animal is in a feeding posture, fully extended, cilia whirling to set-up water currents that draw food particles into the open gullet (mouth). However, when disturbed, the fibre contracts and the bell is pulled against the substrate. out of harm's way.
asexual reproduction	A ciliated protozoan undergoing asexual reproduction, which is similar to growth related cell division in multicelled organisms. Once separated, they become "daughter cells" which, barring a DNA mutation event, makes them genetically identical.
Haemotococcus pluvialis	The red cells are Haemotococcus pluvialis, members of a group of protozoa broadly known as "photosynthetic flagellates". They contain pigments  for capturing sunlight to produce, and store energy. They move by means of highly modified cilia referred to as flagella ("little whips"). The red colour is due to a specific pigment, haematochrome (related to blood haemoglobin). In the Spring, blooms of these plants can turn bird bath water, and even snow, red. (A small ciliate is undergoing asexual reproduction at the top of the frame.)
amoeba	Tiny amoeba "feeding" on bacteria. The image was captured using phase contrast illumination, which greatly enhances detail in this type of subject. Some of the internal structure can be seen as well as the bacteria ingested by some of these animals. Amoeba are like bags of Jell-O, and can engulf prey by simply flowing around it. In this instance the bacteria did not move quickly and soon ended up engulf in a food vacuole inside the amoeba.
Stentor	A fully extended Stentor sp.   The trumpet shaped body is attached to a strand of filamentous algae. The animal is uniformly ciliated, with longer cilia arranged around the mouth of the "trumpet". These beat in a co-ordinated manner, creating a vortex that sweeps small particles into the area of gullet, were suitable ones are ingested.