Demonstration Sheets for Amebas, Ciliates, Miscellaneous Phyla (Lab 10)
[Figures & page numbers are from Roberts & Janovy, 2009, 8th ed.]
Phylum Sarcodina, Class Lobosea, Family Endamoebidae
Trophozoite Entamoeba histolytica
Observe: 1. Nucleus, 2. Endosome (= nucleolus) in center of nucleus, 3. Chromatin on
periphery of nucleus, 4. Vacuoles, 5. One pseudopod
92W 4083, oil
Phylum Sarcodina, Class Lobosea, Family Endamoebidae
Cyst Entamoeba histolytica
Transmission stage has 4 nuclei. See Fig. 7.4, p. 110.
4-2, oil
Phylum Sarcodina, Class Lobosea
Naegleria fowleri
These cells have been cultured free of host tissue, so they represent the freeliving stage of this facultative parasite. Pseudopodia are more easily seen if one
focuses up and down. See Fig. 7.13 (p. 117).
92W 4128, oil
Phylum Sarcodina, Class Lobosea
Naegleria fowleri in situ
Cells of this facultative parasite have invaded vertebrate brain tissue. Darkly
stained cells of the parasite are visible inside and around the periphery of the lighter
stained host tissue. It is difficult to recognize pseudopodia in this preparation. See Fig.
7.18 (p. 120) for photograph of a related species in a baboon brain.
92W 4129, 40X
Ciliophora, Class Litostomatea
Balantidium coli
Trophozoites in fecal smear. Individuals can be easily recognized as ciliates by
the prominent, large macronucleus. See Fig. 10.3 (p. 176).
CBS PS 1100, 40X
Phylum Ciliophora, Order Entodiniomorphida
These ciliate symbionts were collected from the lumen of a sheep. Members of
this order are found as commensals in ruminant mammals. See Fig. 10.5 (p. 177).
92W 0494, 10X
Phylum Mollusca; Class Bivalvia; Family Unionidae
Glochidium larvae
Freshwater unionid mussels are able to colonize upstream habitats by producing
larvae that parasitize fish. The larvae burrow into fin and gill tissues where they feed
upon host fluids as a true parasite. Upon completion of development, the juveniles drop
off hosts, who have moved up and downstream since infection, burrow into the
substrate of the stream and become filter feeders.
CBS Z 1480, 10X
Phylum Annelida; Class Hirudinea
Leech
Leeches are segmented worms with two suckers. Although many are true
predators of invertebrates, their infamous reputation comes from the few species that
are micropredators on vertebrates.
92W 1851, Dissecting scope
Phylum Nematomorpha
Horsehair Worm
These fairly large worms have juvenile stages that parasitize the body cavities of
large arthropods. When nematomorphs mature in terrestrial hosts, their hosts seek out
and enter freshwater which stimulates the worms emerge resulting in host death. This
specimen was found in a well in Brazil. The sudden appearance of adult horsehair
worms in water troughs led to the “folk wisdom” explanation that these worms
developed from hairs that had been shed by drinking horses. Nematomorphs can be
distinguished externally from nematodes by the presence of blunt (rather than pointed)
ends.
Specimen, Dissecting scope
Phylum Nemertea
Carcinonemertes
Most nemerteans are free-living predatory worms that catch their prey with a
conspicuous proboscis that you cannot see on these specimens. Members of the family
represented by these specimens are symbionts that feed on the eggs of crabs. They
live in the external egg masses of egg-bearing females and feed on the eggs and are
known as “egg predators.”
Specimen, Dissecting Scope
Kingdom Plantae
Haustoria of Dodder
This twig is from an oak growing across the street from the Life Science Building.
It was parasitized by a dodder plant whose yellow tendrils have since fallen off. Open
“wounds” or scars where the dodder’s haustoria penetrated the host tree are visible.
Specimen, Dissecting scope
Kingdom Plantae
Dodder
Although some species of dodder contain low numbers of chloroplasts giving
them a slight yellow green tinge as seen in these specimens, the plants are true
parasites in that they acquire nutrients from host plants.
Specimen
Kingdom Plantae
Indian Pipe
This specimen was collected from the pine forest along the university’s Nature
Trail. Indian pipes have no chlorophyll and can be recognized in the wild by their
opaque white coloration. The dark coloration of this specimen is an artifact of
preservation. Indian pipes actually parasitize ectomychorrhizal fungi that form
mutualistic associations with plants. The parasitic plant extracts sugars from the fungus
that were produced in the tree.
Specimen
Phylum Myxozoa
PANSPOROBLAST
The cyst located on gills of this fish is a pansporoblast and is filled with spores
that will infect any predatory fish that feeds on this host.
CBS PS 445, 10X
Phylum Myxozoa
Myxosoma
This genus was introduced to North America from fish stock imported from
Europe. It causes “whirling disease” in native North American trout and salmon. Spores
inside the pansporoblast contain polar capsules each filled with a filament ending in a
harpoon-like structure that becomes embedded in a cell lining the digestive tract of the
new host. The polar filaments reflect light fairly well and glisten under oil immersion.
Focus up and down to see the nucleus clearly.
CBS PS 445, oil
Phylum Apicomplexa; Subclass Gregarinasina; Suborder Septatorina
Cephaline Gregarines
Gregarines in this suborder are common in insects. The two slides on display are
cross-sections through larval mealworms. Members of the Septatina or cephaline
gregarines are characterized by a septum that divides the cell into two sections. The
posterior portion or deutomerite contains the nucleus. Observe the protomerite, septum,
epimerite (hard to see), deutomerite, and nucleus in deutomerite.
PS 415, 40X
Phylum Apicomplexa; Subclass Gregarinasina; Suborder Septatorina
Gregarine Reproduction
Two individuals or gamonts have paired prior to forming a cyst. See Figure 8.3d
(p. 126).
Wards 92W 4543, 40X
Phylum Cnidaria; Class Anthozoa
Parasitic Sea Anemone Edwardsia sp.
This specimen (undescribed species) was collected from the medusa stage of
another cnidarian, the moon jellyfish Aurelia, in the Gulf of Mexico. The parasite feeds
on the gonads of its hosts. Due to the fixation process, the tentacles of the sea
anemone have withdrawn into its body cavity.
Specimen
Phylum Chordata; Subphylum Vertebrata; Class Osteichthyes
CANDIRU
These catfish live in the Amazon and Orinoco Rivers of South America. They
feed on gills of other fish which they locate by following an ammonia trail. Strictly
speaking, their trophic and ecological interactions classify them as micropredators and
along with vampire bats, they have adapted a life-style that is close as vertebrates have
come to true parasitism. Occasionally candiru, responding to ammonia in a urine
stream from a mammal “taking a leak” in a stream, will become lodged in the urethra of
the unfortunate victim.
Specimen