PHOTOS of BACTERIA USING OIL IMMERSION(1000X):
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NOTE: Unless otherwise stated, the Gram Stain was used to visualize the microbes in the micrographs...
|The 3 major shapes of
Rod or bacilli
Vibrio or comma-shaped
Cocci or completely round
|Bacteria are usually one of
three shapes: round (cocci), rod (bacilli), or wavy (spirochetes/spirillae/vibrio).
Genera that are examples of round or spherical bacteria are Staphylococcus
and Streptococcus . Escherichia coli and Bacillus are
rod-shaped bacteria. Treponema are spirochetes and Spirillum are
All images are at 1000 X magnification.
bacteria on a positive capsule stain
Some bacteria, such as the Klebsiella pneumoniae bacteria shown in these 1000 X images, produce capsules. Capsules are made of sticky substances such as polysaccharides that are secreted by the bacteria and adhere to the cell. Capsules inhibit phagocytosis in the infected host and thus enhance survival of the bacteria. Anthony's method, a negative staining technique, was used to make the capsules visible in these images. Utilizing crystal violet and copper sulfate, Anthony's method results in a dark purple background and purple rod-shaped Klebsiella bacteria surrounded by white (refractile) capsules (CV-Capsule Staining used)....
|Campylobacter sp. are slender Gram-negative vibroid cells, possessing one or more helical turns. Campylobacter fetus are shown here at 1000 X magnification, stained with the Gram stain. They appear as tiny red comma-shaped organisms. Sometimes two Campylobacter appear in a "V" pattern resembling seagull wings. Pathogenic species in the genus Campylobacter include C. fetus, which causes spontaneous abortion in domestic animals, and C. jejuni, a cause of foodborne intestinal disease. It is not possible to distinguish different genera of Campylobacter from one another by a Gram stain. Biochemical tests must be run for complete identification.|
|Campylobacter bacteria exhibiting a spiral shape and 2 spirals = "gull wing" shape|
|Corynebacterium xerosis, a nonpathogenic diptheroid with metachromatic granules that occurs in palisades. This image contains a magnified view of bacteria in a palisade, with several of the bacteria outlined for clarity.|
|Clostridium tetani is a pathogenic bacterium that causes tetanus or "lockjaw". This slide shows Clostridium tetani bacteria that are producing spores at 1000 X magnification. Stained with methylene blue, the vegetative rods (bacilli) are dark blue in color and the spores, which do not take up the dye as readily, are light blue. Clostridium tetani is known for the "tennis racket" shape it has due to its terminal spores.|
very small Gram-negative rods, as seen here at 1000 X magnification.
Escherichia coli is often called a "cocobacillus" because
its rod is almost "round." E. coli is a normal
bacterial inhabitant of the large intestine of vertebrates, including
humans. It is beneficial to humans because it produces vitamins we need
and aids in digestion of food. However, some strains of E. coli are
pathogenic. For example, E.coli O157:H7 has been implicated in foodborne
disease, causing bloody diarrhea.
|Neisseria gonorrhoeae is the pathogenic bacterium that causes gonorrhea. This slide shows Neisseria gonorrhoeae colonies growing on blood agar. N. gonorrhoeae are identified as "Gram-negative intracellular diplococci". The next slide shows uninfected white blood cells stained with the Gram stain.|
|N. gonorrhoeae present in a urethral or vaginal discharge stained with the Gram stain at 1000X magnification. The bacteria have been phagocytized by white blood cells (neutrophils). The nuclei of the white blood cells are the large red circles, while the bacteria are the small red circles that tend to be in pairs (diplococci) and Gram-negative.|
Micrococcus sp. also present as diplococci. These bacteria are GRAM positive however and may also show in tetrads. NOTE that different species of Micrococcus present with pigmented colonies on agar. M. roseus is red-orange while M. luteus is yellow.
Some other Genera produce pigmented rose colonies as well. Serratia marcescens, a GRAM-negative rod has a temperature dependant pigment that presents best at 25 degrees C; it shows a white colony when grown at 37 C.
|Both Micrococcus sp. and Sarcina sp.are Gram-positive cocci that more than one plane. Sarcina remain attached in packets of eight cells, forming a cube. However, often a two-dimensional image such as those shown here, reveals only the four cells (tetrad) in the plane nearest our vision. Another four bacteria are stacked behind the four we can see.|
|Green endospores... Because the endospores in these images occur at the end of the rod, they are designated as "terminal" spores. Endospores that occur in the middle of a rod are termed "central", while endospores located between the middle and end of a rod are termed "subterminal". Endospores occur by themselves after the death of the vegetative rod to which they were attached.|
|VIBRIO, SPIRILLAE, AND
Spirillum are wavy shaped-bacteria.
|Treponema pallidum is the pathogenic spirochete that causes syphilis.|