Excavates

This scanning electron micrograph (SEM) depicted a Giardia specie intestinal protozoan on the microvillous border of intestinal epithelial cells. Each small circular profile under the protozoan represents the rounded tip of a single microvillous, and it is estimated that 2000 to 3000 microvilli cover the surface of a single intestinal epithelial cell. The ventral adhesive disk, which facilitates adherence to the intestinal surface, can be seen on the underside of the organism.Created: 1998

This is a transmission electron micrograph (TEM) of a thin section cut through the ventral adhesive disk (suction-cup-like structure) of a Giardia sp. protozoan, which had adhered itself to the mucosal comb-like microvillous border of an intestinal epithelial cell from a rat ileum. Note the monolayer of microtubules in the organism’s ventral adhesive disk.Created: 1996

This scanning electron micrograph(SEM) depicted the mucosal surface of the small intestine of a gerbil infested with Giardia sp. protozoa. The intestinal epithelial surface is almost entirely obscured by the attached Giardia trophozoites.Created: 1988

This scanning electron micrograph (SEM) depicted some of the ultrastructural morphologic details of an oblong-shaped Giardia sp. protozoan cyst, revealing the filamentous nature of the cyst wall. Each cyst-wall filament is approximately 7 to 20 nanometers (nm) thick. Note that this cyst was undergoing "excystation", and was captured at a point in the process where a flagellated trophozoite was beginning to emerge from the right side of the cyst.Created: 1999

This scanning electron micrograph (SEM) depicted some of the ultrastructural morphologic details of an oblong-shaped Giardia sp. protozoan cyst, revealing the filamentous nature of the cyst wall. Each filament is approximately 7 to 20 nanometers (nm) thick.Created: 1999

These three scanning electron micrographs (SEM) revealed under successively greater magnifications, some of the ultrastructural morphologic details of a Giardia trophozoite, where it had attached itself to apical microvilli, i.e., numerous small cylindrical structures, some highlighted with white arrowheads in the far left photograph, that covered the mucosal surface of a Caco-2 cultured intestinal epithelial cell. The ventrolateral flange, i.e., ruffle-like structure that surrounds the anterior portion of the protozoan, appeared firmly attached, by way of focal adhesions, to these microvilli.Created: 2009

This thin-section transmission electron micrograph (TEM) revealed some of the ultrastructural morphology found within the cyst-stage of a Giardia sp. protozoan. The outer cyst wall is composed of filamentous and membranous portions, and is separated from the cytoplasm of the trophozoites contained within by the peritrophic space. This cyst wall is approximately 0.25 microns thick.Created:

This scanning electron micrograph (SEM) depicted the dorsal (upper) surface of the intestinal protozoan, Giardia. Some of the identifying morphologic characteristics include pairs of thread-like flagella that facilitate motility, and a ventolateral flange that appears as a ruffle around the anterior portion of the organism.Created:

This scanning electron micrograph (SEM) depicted the dorsal (upper) surface of a Giardia protozoan that had been isolated from a rat’s intestine. Some of the identifying morphologic characteristics include pairs of thread-like flagella that facilitate motility, and a ventolateral flange that appears as a ruffle around the anterior portion of the organism. Pairs of flagella seen here include an anterior, posterior-lateral, and caudal pairs.Created: 1982

This digitally-colorized scanning electron micrograph (SEM) depicted some of the ultrastructural morphologic details of an oblong-shaped Giardia sp. protozoan cyst, revealing the filamentous nature of the cyst wall. Each cyst-wall filament is approximately 7 to 20 nanometers (nm) thick. Note that this cyst was undergoing "excystation", and was captured at a point in the process where a flagellated trophozoite was beginning to emerge from the right side of the cyst.Created: 1999

This digitally-colorized scanning electron micrograph (SEM) depicted the dorsal (upper) surface of a Giardia protozoan that had been isolated from a rat’s intestine. Some of the identifying morphologic characteristics include pairs of thread-like flagella that facilitate motility, and a ventolateral flange that appears as a ruffle around the anterior portion of the organism. Pairs of flagella seen here include an anterior, posterior-lateral, and caudal pairs.Created: 1982

Under a moderate magnification of 2000X, this digitally-colorized scanning electron micrograph (SEM) of an untreated water specimen extracted from a wild stream mainly used to control flooding during inclement weather, revealed the presence of unidentified organisms, which included bacteria, protozoa, and algae. In this particular view, a single copepod-like microorganism was seen occupying the field of view. Also, if you look closely towards the upper right corner, you’ll also notice the small grouping of bacteria, which had become enmeshed in a patch of biofilm.Created: 2009

Under a moderately-high magnification of 2500X, this digitally-colorized scanning electron micrograph (SEM) of an untreated water specimen extracted from a wild stream mainly used to control flooding during inclement weather, revealed the presence of unidentified organisms, which included bacteria, protozoa, and algae. In this particular view, a microorganism is featured, the exterior of which is covered by numerous projections imparting an appearance of a sea urchin. This microscopic pin cushion was teathered to its surroundings by a biofilm within which many bacteria, and amoeboid protozoa could be seen enmeshed as well. See PHIL 11781 for a greater magnification of this organism’s exterior.Created: 2009

Under a moderate magnification of 2000X, this digitally-colorized scanning electron micrograph (SEM) of an untreated water specimen extracted from a wild stream mainly used to control flooding during inclement weather, revealed the presence of unidentified organisms, which included bacteria, protozoa, and algae. In this particular view, a single copepod-like microorganism was seen occupying the field of view, which seemed to be encased in an outer shell of armour-like plates, or scales. If you look closely, you’ll also notice the small grouping of bacteria, which had become enmeshed in a patch of biofilm on the dorsal surface of this creature's carapace.Created: 2009

Under a moderate magnification of 1000X, this digitally-colorized scanning electron micrograph (SEM) of an untreated water specimen extracted from a wild stream mainly used to control flooding during inclement weather, revealed the presence of unidentified organisms, which included bacteria, protozoa, and algae. In this particular view, a single copepod-like microorganism was seen occupying the field of view, which seemed to be encased in an outer shell of armour-like plates, or scales. If you look closely, you’ll also notice the small grouping of bacteria, which had become enmeshed in a patch of biofilm.Created: 2009

Under a relatively low magnification of 121X, this digitally-colorized scanning electron micrograph (SEM) of an untreated water specimen extracted from a wild stream mainly used to control flooding during inclement weather, revealed the presence of unidentified organisms, which included bacteria, protozoa, and algae. In this particular view, numbers of what appeared to be rod-shaped sections of various sizes were scattered throughout the field of view, which though unconfirmed, may have been vegetative in nature, and possibly algal organisms. There were also patches of biofilm present as well.Created: 2009

Under a relatively low magnification of 200X, this digitally-colorized scanning electron micrograph (SEM) of an untreated water specimen extracted from a wild stream mainly used to control flooding during inclement weather, revealed the presence of unidentified organisms, which included bacteria, protozoa, and algae. In this particular view, numbers of what appeared to be rod-shaped sections of various sizes were scattered throughout the field of view, which though unconfirmed, may have been vegetative in nature, and possibly algal organisms. There were also patches of biofilm present as well.Created: 2009

Under a moderate magnification of 1000X, this scanning electron micrograph (SEM) of an untreated water specimen extracted from a wild stream mainly used to control flooding during inclement weather, revealed the presence of unidentified organisms, which included bacteria, protozoa, and algae. In this particular view, a single copepod-like microorganism was seen occupying the field of view, which seemed to be encased in an outer shell of armour-like plates, or scales. If you look closely, you’ll also notice the small grouping of bacteria, which had become enmeshed in a patch of biofilm. See PHIL 11787 for a colorized version of this image.Created: 2009

This digitally-colorized scanning electron micrograph (SEM) of an untreated water specimen extracted from a wild stream mainly used to control flooding during inclement weather, revealed the presence of unidentified organisms, which included bacteria, protozoa, and algae. Occupying most of the field of view, an unidentified amorphous mucoidal biofilm was featured, which appeared to have enmeshed numbers of amoeboid organisms, while on the right was a strangely-beautiful microorganism displaying an outer surface studded with numerous projections, making it appear like a microscopic sea urchin.Created: 2009

At a magnification of 2000X, this digitally-colorized scanning electron micrograph (SEM) of an untreated water specimen extracted from a wild stream, which is mainly used to control flooding during inclement weather, revealed the presence of unidentified organisms, which included bacteria, protozoa, and algae. In this particular image, an expanding amorphous organic biofilm was featured.Created: 2009

This digitally-colorized scanning electron micrograph (SEM) of an untreated water specimen extracted from a wild stream mainly used to control flooding during inclement weather, revealed the presence of unidentified organisms, which included bacteria, protozoa, and algae. In this particular image, unidentified sheets of algae were wrapped in a mass of what appeared to be a mucoid amorphous biofilm.Created: 2009

This digitally-colorized scanning electron micrograph (SEM) of an untreated water specimen extracted from a wild stream mainly used to control flooding during inclement weather, revealed the presence of unidentified organisms, which included bacteria, protozoa, and algae. Visible in this particular image were a number of different microorganisms including elongated diatoms, and an amorphic gelatinous biofilm mass, which had enveloped amoeboid and bacterial organisms.Created: 2009

This digitally-colorized scanning electron micrograph (SEM) of an untreated water specimen extracted from a wild stream mainly used to control flooding during inclement weather, revealed the presence of unidentified organisms, which included bacteria, protozoa, and algae. Here we see what appeared to be examples of diatomic, bacterial, and protozoan species, which were but a few of the inhabitants of this fresh water stream. Note also the amorphic gelatinous biofilm within which were embedded bacteria, and amoebic microorganisms.Created: 2009

This digitally-colorized scanning electron micrograph (SEM) of an untreated water specimen extracted from a wild stream mainly used to control flooding during inclement weather, revealed the presence of unidentified organisms, which included bacteria, protozoa, and algae. Clearly visible in the center of this image, was a exquisitely-formed unidentified round vescicle-shaped microorganism, which may have been algal, or diatomic. Shaped like an ancient Grecian urn, the almost perfectly rounded smooth, flawless surface was made even more beautiful given its delicate structure.Created: 2009