Amoeba proteus - MDC Faculty Home Pages
Amoeba proteus, previously Chaos diffluens, is an amoeba closely related to the giant amoebae.
This small PROTOZOAN uses tentacular protuberances called PSEUDOPODIA to move and
phagocytosize smaller unicellular organisms, which are enveloped inside the cell's cytoplasm in a
food vacuole, where they are slowly broken down by enzymes. Amoeba proteus is very wellknown for its extending pseudopodia. A. proteus possesses a nucleus containing granular
chromatin, and is therefore a EUKARYOTE.
Anabaena is a genus of filamentous cyanobacteria, or blue-green algae, found as
plankton. It is known for its nitrogen fixing abilities, and they form symbiotic relationships with certain
plants, such as the mosquito fern. They are one of four genera of cyanobacteria that produce
neurotoxins, which are harmful to local wildlife, as well as farm animals and pets. Production of
these neurotoxins is assumed to be an input into its symbiotic relationships, protecting the plant from
Mold (Aspergillus) Conidiophores
As one of the two common genera of molds on fruits and other foods such as grain, wheat, and
bread, species of the genus Aspergillus are distinguished from Penicillium species by the origin of
their spore-bearing stalks or conidiophores. In Aspergillus, the conidiophore arises from a foot-cell,
a vegetative mycelium.
The protoplasm of a cell nucleus.
The genus Coprinus is a small genus of mushrooms consisting of Coprinus
comatus (the shaggy mane) and several of its close relatives. Until 2001, Coprinus was
a large genus consisting of all agaric species in which the lamellae autodigested to
release their spores. (The black ink-like liquid this would create gave these species their
common name "inky cap".) Molecular phylogenetic investigation found that Coprinus
comatus was only a distant relative of the other members of Coprinus, and was closer
to genera in the Agaricaceae. Since Coprinus comatus is the type species of Coprinus,
only that species and its close relatives C. sterquilinus and C. spadiceisporus retained
the name of the genus
The majority of species of Coprinus were therefore reclassified into the genera
Coprinellus, Coprinopsis, and Parasola.Coprinus and these segregate genera are now
referred to collectively as coprinoid fungi.
Euglena is a genus of unicellular protists, of the class Euglenoidea of the phylum
Euglenophyta, also known as Euglenozoans. They are single-celled organisms.
Currently, over 1000 species of Euglena have been described. Marin et al. (2003)
revised the genus to include several species without chloroplasts, formerly classified as
Astasia and Khawkinea. Some Euglena are considered to have both plant and animal
features. Due to these dual characteristics, much debate has arisen to how they have
evolved, and into which clade they should be placed. Euglenas were originally placed in
the kingdom Protista but now are classisfied above the kingdom Euglenozoa, which
contains both Kinetoplastids and Euglenids.
A Euglena is a protist that can both eat food as animals by heterotrophy; and can
photosynthesize, like plants, by autotrophy. When acting as a heterotroph, the Euglena
surrounds a particle of food and consumes it by phagocytosis. When acting as an
autotroph, the Euglena utilizes chloroplasts, containing Chlorophyll A, Chlorophyll B,
and some carotenoid pigments, to produce sugars by photosynthesis. Euglenas are
able to move through aquatic environments by using a large, rear mounted flagellum for
locomotion. Euglenas reproduce asexually by fission, and there has been no existence
of sexual reproduction.
Fucus male conceptacle
Fucus, better known as kelp or seaweed, is a genus of exclusively-marine brown
macroalgae in the family Phaeophyceae. The phytopigment fucoxanthin masks the
natural green of the chlorophylls in these multicellular intertidal and subtidal plants.
Known also as wracks, the Fucus brown seaweeds are always diploid and meiosis
takes place before the gametes are formed. The reproductive organs of the macroalgae
consist of receptacles and conceptacles. Gamete production takes place in specialized
crypt-like structures known as conceptacles. The conceptacles are carried in
receptacles, which are swollen areas found at the tips of the plants. While some
species of wracks are dioecious, others feature both types of sexual organs on one
plant and are classified as monoecious. To add to the diversity of reproductive strategy
featured by this genus of brown algae, some of the monoecious species have both
sexes in a single conceptacle while others contain them in separate organs. The
conceptacles for the male reproductive organs are lined with antheridiophores, which
are branched and feature inflated, terminal antheridia on their branches. The antheridia
are the sites of meiosis, forming 64 to 128 biflagellated male gametes that are referred
to as antherozoids. The male and female gametes are usually released into the water
during a rising tide with the female eggs emitting a potent volatile hydrocarbon
compound (fucoserraten), which acts as an attractant for the mobile male antherozoids.
The fertilized egg settles onto the sediment and germinates as a new diploid thallus.
fucus monoecious conceptacles
Fucus is a genus of brown alga in the Class Phaeophyceae to be found in the intertidal
zones of rocky seashores almost everywhere in the world. Known also as wracks, the
Fucus brown seaweeds are always diploid and meiosis takes place before the
gametes are formed. The reproductive organs of the macroalgae consist of receptacles
and conceptacles. Gamete production takes place in specialized crypt-like structures
known as conceptacles. The conceptacles are carried in receptacles, which are swollen
areas found at the tips of the plants
Diatoms (Greek: διά (dia) = "through" + τέμνειν (temnein) = "to cut", i.e., "cut in half")
are a major group of eukaryotic algae, and are one of the most common types of
phytoplankton. Most diatoms are unicellular, although they can exist as colonies in the
shape of filaments or ribbons (e.g. Fragillaria), fans (Meridion), zigzags (Tabellaria), or
stellate colonies (Asterionella). Diatoms are producers within the food chain. A
characteristic feature of diatom cells is that they are encased within a unique cell wall
made of silica (hydrated silicon dioxide) called a frustule.
Oscillatoria is a genus of filamentous cyanobacteria which is named for the oscillation
in its movement. Filaments in the colonies can slide back and forth against each other
until the whole mass is reoriented to its light source. It is commonly found in wateringtroughs waters, and is mainly blue-green or brown-green. Oscillatoria is an organism
that reproduces by fragmentation. Oscillatoria forms long filaments of cells which can
break into fragments called hormogonia. The hormogonia can grow into a new, longer
filament. Breaks in the filament usually occur where dead cells(necridia) are present.
Oscillatoria uses photosynthesis to survive and reproduce.
Paramecia, also known as Lady Slippers, due to their appearance, are a group of unicellular
ciliate protozoa, which are commonly studied as a representative of the ciliate group, and range
from about 50 to 350 μm in length. Simple cilia cover the body, which allow the cell to move
with a synchronous motion (like a caterpillar). There is also a deep oral groove containing
inconspicuous compound oral cilia (as found in other peniculids) used to draw food inside. They
generally feed on bacteria and other small cells. Osmoregulation is carried out by a pair of
contractile vacuoles, which actively expel water from the cell absorbed by osmosis from their
Paramecia are widespread in freshwater environments, and are especially common in scums.
Certain single-celled eukaryotes, such as Paramecium, are examples for exceptions to the
universality of the genetic code (translation systems where a few codons differ from the standard
Penicillium (from Latin penicillus: paintbrush) is a genus of ascomycetous fungi of
major importance in the environment, food and drug production. The thallus ,
(mycelium) typically consists of a highly branched network of multinucleate, septate,
usually colorless hyphae. Many-branched conidiophores sprout on the mycelia, bearing
individually constricted conidiospores. The conidiospores, are the main dispersal route
of the fungi, and often green.
Sexual reproduction involves the production of ascospores, commencing with the fusion
of an ascogonium and an antheridium, with sharing of nuclei. The irrregularly distributed
asci contain eight unicellular ascospores each.
Peridinium is a dinoflagellate with thick, armored plates that are often lobed and
ornamented. The sutures are quite noticeable, and the cingulum is nearly at the cell
median. The cells may be generally round to oval-shaped or flattened, with a convex
dorsal surface and a concave ventral surface. Some species (such as Peridinium
limbatum) have distinctive horns. The genus has over 30 species, most of which are
Physarum plasmodiumbelongs to the supergroup Amoebozoa, phylum Mycetozoa, and class
Myxogastria. P. polycephalum, often referred to as the “many-headed slime,” is a slime mold that
inhabits shady, cool, moist areas, such as decaying leaves and logs. This protist may be seen
without a microscope; P. polycephalum is typically yellow in color, and eats fungal spores, bacteria,
and other microbes. P. polycephalum is one of the easiest eukaryotic microbes to grow in culture,
and has been used as a model organism for many studies involving amoeboid movement and cell
motility. Most organisms receive mitochondrial DNA from their mother, but it is not known from where
P. polycephalum receives its mitochondrial DNA as it is currently not possible to distinguish between
male and female.
Saccharomyces budding cells
The yeast open species Saccharomyces cerevisiae has been used in baking and fermenting
alcoholic beverages for thousands of years. It is also extremely important as a model organism in
modern cell biology research, and is one of the most thoroughly researched eukaryotic
microorganisms. Researchers have used it to gather information about the biology of the eukaryotic
cell and ultimately human biology. Other species of yeast, such as Candida albicans, are
opportunistic pathogens and can cause infections in humans. Yeasts have recently been used to
generate electricity in microbial fuel cells,and produce ethanol for the biofuel industry.
Saprolegnia is a genus of freshwater mould often called a "cotton mould" because of the
characteristic white or grey fibrous patches it forms. Current taxonomy puts Saprolegnia as a genus
of the heterokonts in the order Saprolegniales. Saprolegnia is tolerant to a wide range of
temperature, 3°C to 33°C, but is more prevalent in lower temperatures. While it is found most
frequently in freshwater, it will also tolerate brackish water and even moist soil. Saprolegnia
filaments (hyphae) are long with rounded ends, containing the zoospores. Saprolegnia generally
travels in colonies consisting of one or more species. They first form a mass of individual hyphae.
When the mass of hyphae grows large enough in size to be seen without use of a microscope, it can
be called a mycelium. Colonies are generally white in color, though they may turn grey under the
precesence of bacteria or other debris which has become caught in the fibrous mass.
Rhizopus is a genus of molds that includes cosmopolitan filamentous fungi found in soil,
decaying fruit and vegetables, animal faeces, and old bread. Rhizopus species produce both
asexual and sexual spores. The asexual sporangiospores are produced inside a pinhead-like
structure, the sporangium, and are genetically identical to their parent. In Rhizopus, the sporangia
are supported by a large apophysate columella, and the sporangiophores arise among distinctive
rhizoids. Dark zygospores are produced after two compatible mycelia fuse during sexual
reproduction. They give rise to colonies that may be genetically different from their parents.
Some Rhizopus species are opportunistic agents of human zygomycosis. They may cause serious
(and often fatal) infections in humans and animals because of their rapid growth rate and growth
at relatively high temperatures.
Spirogyra is a genus of filamentous green algae of the order Zygnematales, named for the helical or
spiral arrangement of the chloroplasts that is diagnostic of the genus. It is commonly found in
freshwater areas, and there are more than 400 species of Spirogyra in the world. Spirogyra
measures approximately 10 to 100μm in width and may stretch centimeters long. Spirogyra is
unbranched with cylindrical cells connected end to end in long green filaments. The cell wall has two
layers: the outer wall is composed of cellulose while the inner wall is of pectin. The cytoplasm forms
a thin lining between the cell wall and the large vacuole it surrounds. Chloroplasts are embedded in
the peripheral cytoplasm; their numbers are variable (as few as one). The chloroplasts are ribbon
shaped, serrated or scalloped, and spirally arranged, resulting in the prominent and characteristic
green spiral on each filament. Each chloroplast contains several pyrenoids, centers for the
production of starches, appearing as small round bodies.
Stemonitis is a distinctive genus of slime molds found throughout the world
(except Antarctica). They are characterised by the tall brown sporangia, supported on
slender stalks, which grow in clusters on rotting wood. Identification within the genus is
difficult, and can only be performed with confidence using a microscope.