Protists

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Protists
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PROTISTS

• There are astonishing numbers of organisms in a
  single drop of pond water.
• Some of these tiny organisms propel themselves
  with whipping flagella, while others creep along
  by means of blob-like appendages.
• Some resemble miniature jewelry others look like
  tumbling green globes.
• These beautiful creatures belong to a group of
  unicellular eukaryotes known as protists.

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PROTISTS

• Protists are an extremely diverse assortment of
  organisms.
• Some protists are autotrophic (make their own
  food with chlorophyll and sunlight) like plants
  others are heterotrophic (ingest their food) like
  animals.
• Most protists are aquatic and are found almost
  anywhere there is water.
• The two types of protists we will cover are
  algae, which are not pathogenic but cause
  problems in aquariums and swimming pools, and
  protozoa, which are single-celled animals (we
  will only discuss the protozoas that cause
  disease).

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Video

• Protists 4 mins

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ALGAE

• These are the producers of the ecosystem because
  they have chloroplasts which contain chlorophyll
  so they can use photosynthesis to make food
  other organisms eat them and get their food that
  way.
• They are at the bottom of the food chain.

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ALGAE

• Many algae are unicellular, some are
  multicellular, and others live in colonies.

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ALGAE

• They produce oxygen that is needed for all other
  life forms on earth.
• Without algae there would not be enough oxygen on
  earth.
• They do not cause diseases in humans, but they
  can be a nuisance in aquariums and swimming
  pools.
• Algae are mainly classified by their colors from
  their pigment composition.

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GREEN ALGAE

• Ancient green algae most likely gave rise to the
  first plants and their chloroplasts are very
  similar.
• Chloroplasts are the organelles that contain
  chlorophyll (a green pigment) and use sunlight to
  make food.

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GREEN ALGAE

• Most algae are found in fresh water as well as
  marine water, but some species of green algae
  have even adapted to snow and are found in high
  altitude glaciers where its pigments produce an
  effect known as watermelon snow.

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RED ALGAE

• Red algae are the most abundant large algae in
  warm tropical oceans.
• The largest are included in the informal
  designation seaweeds although they are not as
  big as the giant brown kelps.

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GOLDEN ALGAE

• Golden algae have two flagella near one end of
  the cell which they use for motility.
• Some species can form resistant cysts that can
  survive for decades when environmental conditions
  are poor.

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BROWN ALGAE

• Brown algae are multicellular and are the largest
  type of algae.
• It is mostly found in cool bodies of saltwater.
• They are the most common species of seaweeds.

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BROWN ALGAE

• They are the most complex of all algae some even
  have specialized tissues and organs that resemble
  those in plants.
• Seaweed is an important commodity for humans.
  Many types of seaweed are harvested for food,
  including for soups, crispy sheets, and wraps for
  sushi. Seaweed is also used to put in many
  processed foods such as pudding, ice cream, and
  salad dressing.

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DIATOMS

• Diatoms are unicellular, photosynthetic algae.
  They are unique because their cell walls are made
  of a glass-like substance called silica.
• When a diatom dies, it leaves behind its
  fossilized walls.

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DIATOMS

• These fossils, combined with soil sediments, are
  known as diatomaceous earth, which is sold as
  bags of soil for houseplants because it provides
  good drainage and aeration. They are also used
  for filters and as a grinding and polishing agent.

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DINOFLAGELLATES

• Single celled algae that are motile and are
  shaped like an acorn with armored plates.
• Often cause red tides and massive fish kills.

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• Protists, algae 4 mins

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BLUE-GREEN ALGAE

• What is called blue-green algae is actually not
  a true alga, but a bacterium called
  cyanobacteria, which contains chlorophyll and is
  able to make its own food.

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BLUE-GREEN ALGAE

• However, it can turn lakes and aquariums an
  unsightly green color, and is a common nuisance.

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BLUE-GREEN ALGAE

• It is beneficial to other marine plants because
  it recycles nutrients such as nitrogen, but it
  can be a problem because it contributes to algae
  blooms, especially during warm weather.
• Some species produce hydrogen and are being
  investigated as a possible alternative source of
  energy.
• Other species are dangerous to animals and humans
  because they produce toxins.

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NUISANCE ALGAE

• Algae become a nuisance when it grows in swimming
  pools, aquariums, and blooms to excess in oceans.
  
• In swimming pools, it can be easily treated with
  chlorine. However, chlorine is toxic to fish, so
  an algaecide must be used to get rid of the algae
  without harming the fish.
• A typical algaecide works by removing phosphate
  from the water. Without phosphate, algae are not
  able to produce energy, so they die off.

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NUISANCE ALGAE

• The standard chemical used for this is copper
  sulfate when it is exposed to phosphate, it
  becomes copper phosphate, which sinks to the
  ground in a solid form.
• However, in deeper waters with a low oxygen
  content, the copper can disengage from the
  phosphate and become toxic to the environment.

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NUISANCE ALGAE

• For this reason, the use of copper sulfate is
  restricted by the Environmental Protection Agency
  in lakes.
• However, it is still available for commercial use
  in aquariums.

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ALGAE BLOOMS

• Algal blooms are the result of an excess of
  nutrients (particularly phosphorus and nitrogen)
  into waters and higher concentrations of these
  nutrients in water cause increased growth of
  algae and green plants.
• As more algae and plants grow, others die. This
  dead organic matter becomes food for bacteria
  that decompose it.

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ALGAE BLOOMS

• With more food available, the bacteria increase
  in number and use up the dissolved oxygen in the
  water.
• When the dissolved oxygen content decreases, many
  fish and aquatic insects cannot survive.
• This results in a dead zone.

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ALGAE BLOOMS

• Algae blooms especially occur during periods of
  warm weather, so global warming is resulting in
  more algae blooms with subsequent dead zones that
  kill off the shellfish there.
• Algal blooms may also be of concern as some
  species of algae produce neurotoxins which may
  have severe biological impacts on wildlife.
• Algal blooms sometimes occur in drinking water
  supplies. In such cases, toxins from the bloom
  can survive standard water purifying treatments.

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Dead Zones

• Low-oxygen areas in the world's oceans there are
  146 dead zones in the world oceans where marine
  life cannot be supported due to depleted oxygen
  levels.
• Some of these are as small as a square kilometer,
  but the largest dead zone covered 70,000 square
  kilometers.
• In the US, the East Coast's Chesapeake Bay has a
  large dead zone.
• Off the coast of Cape Perpetua, Oregon, there is
  also a huge dead zone. This dead zone is unique
  in that it only exists during the summer, perhaps
  due to seasonal wind patterns.

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Dead Zones
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Dead Zones

• Currently the most notorious dead zone is a
  20,000 square kilometer region in the Gulf of
  Mexico, where the Mississippi River dumps
  high-nutrient runoff from its vast drainage
  basin, affecting important shrimp fishing
  grounds.
• Low oxygen levels have led to reproductive
  problems in fish involving decreased size of
  reproductive organs, low egg counts and lack of
  spawning.

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Gulf of Mexico Dead Zone
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Dead Zones

• Dead zones are not irreversible.
• The Black Sea dead zone, previously the largest
  dead zone in the world, largely disappeared
  between 1991 and 2001 after fertilizers became
  too costly to use following the collapse of the
  Soviet.
• Fishing has again become a major economic
  activity in the region.

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Dead Zones

• While the Black Sea "cleanup" was largely
  unintentional and involved a drop in
  hard-to-control fertilizer usage, the U.N. has
  advocated other cleanups by reducing large
  industrial emissions.
• From 1985-2000, the North Sea dead zone had
  nitrogen reduced by 37 when policy efforts by
  countries on the Rhine River reduced sewage and
  industrial emissions of nitrogen into the water.
• During this time, the US also passed a law
  prohibiting phosphates in laundry detergents, and
  this has helped reduce the algal blooms in our
  country.

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Video

• Dead Zones 15 mins

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PROTOZOA

• Protozoa are larger than bacteria many bacteria
  can fit into a protozoon.
• Protozoa absorb or ingest organic chemicals.

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PROTOZOA

• They are classified according to their motility
  (movement)
• pseudopods (false foot)
• cilia (hairs)
• flagella (tail)

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MEDICALLY IMPORTANT PROTOZOAS

• Archaezoa
• Giardia lambia (giardiasis)
• Amoebas
• Entamoeba histolytica (ameobiasis)
• Apicomplexa
• Plasmodium (malaria)
• Trypanosomes
• Trypanosoma brucii (African Sleeping Sickness)
• Leishmaniasis
• Leishmania (Leishmaniasis)

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ARCHAEZOA

• ARCHAEZOA (archae old these are closely
  related to the first protozoa). They have no
  mitochondria they have multiple flagella.
• A. Giardia lambia Giardia is common worldwide,
  including Southern California, from drinking
  untreated outdoor water. After a few days you
  develop persistent, chronic diarrhea (dysentery).
  The organism looks like a happy face what looks
  like two eyes are nuclei.
• B. Trichomonas vaginalis A common sexually
  transmitted disease which is without symptoms in
  males. It causes severe itchiness in females and
  is easily treated with antibiotics.

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Ghiardia lamblia
Trichomonas vaginalis
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AMEOBAS

• These organisms look like jelly they move by
  pseudopods to get food. Pseudopods are
  characteristic of amoebas. Two main types of
  amoebas that cause disease in humans both
  diseases are called ameobiasis.
• A. Entamoeba histolytica This is a global
  disease that any traveler can get. As soon as you
  cross the border into Mexico, you are exposed to
  it. This organism likes to eat red blood cells.
• B. Balentidium coli It is found wherever humans
  and pigs live nearby each other. It enters the
  human (and dogs) by ingestion of fecal
  contaminants on food, water, and hands. Once in
  the colon, it invades the colon wall, and cause
  ulcerations in the colon. Symptoms include
  diarrhea and GI discomfort.

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Entamoeba histolytica
Entamoeba histolytica with ingested red blood
cells
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APICOMPLEXA

• (api apex top). It is named by an organelle
  called an apical complex which allows the
  organism to attach to the host.
• Two main organisms that cause disease they both
  require an animal vector for transmission to get
  into the blood of the human host.
• Plasmodium (causes malaria)
• Toxoplasma (causes Toxoplasmosis)

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MALARIA

• This disease kills 2-3 million people a year,
  mostly young people and teenagers.
• 200-300 million people are infected each year.
• 2/3 of malaria cases are in Africa.
• Animal vector anopheles mosquito
• Causative agent Plasmodium

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Anopheles Mosquitoes

• Female mosquitoes need blood meals to nourish
  their eggs.

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MALARIA

• Only female anopheles mosquitoes are the vector.
  Only the female mosquito has a needle-sharp
  proboscis (mouth part) that penetrates the skin
  of the human. They need the blood to nourish
  their eggs.
• This is a tropical mosquito found in warm
  environments.
• Since global warming is affecting us, we may see
  an increase in cases of malaria in the US,
  especially California.

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MALARIA

• The term malaria comes from mal air, which
  means bad air.
• They used to think malaria was cause from the bad
  air of a foul-smelling swamp.
• Later it was discovered that the disease was
  caused by the protozoa inside the mosquito.

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MALARIA

• The protozoa migrate into the salivary gland of
  the mosquito, and they are injected into the
  blood of the human.
• They immediately go to the liver.
• This is the only way to get malaria you cant
  get it from a blood transfusion because they only
  spend a short time in the blood. They go right to
  the liver quickly.
• In the liver cells, they form cysts and
  reproduce.
• The cyst eventually ruptures and releases the
  protozoa into the bloodstream, where they enter
  red blood cells (RBCs).

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Malaria
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MALARIA

• The patient now starts to have symptoms.
• The RBC eventually ruptures, and this releases a
  lot of toxins all at once.
• This is what causes the symptoms of abdominal
  pain, myalgia (muscle pain), fever, chills, and
  shivering.
• It takes about 48-72 hours after this for the
  protozoa to infect new RBCs and cause them to
  rupture, setting off a new cycle of symptoms.
• Thus, these symptoms are regular and recurrent
  (described by the term paroxysms).
• This disease also results in anemia.

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MALARIA

• Some of the protozoa are sucked up by another
  mosquito and transmitted to a new human.
• Treatment involved the plant product quinine (in
  the form of Methoquin, Primoquin, etc).
• Sometimes treatment is prophylactic you can take
  it before you go on a trip to Africa to prevent
  the disease.
• Some forms of malaria are chronic.

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Malaria Videos

• Malaria Life Cycle 1 min
• Malaria prevention campaign 1 min
• Maria prevention for travelers 3 mins

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TOXOPLASMOSIS

• Causative agent Toxoplasma
• Animal vector cats (Most warm-blooded animals
  harbor it, especially cats)
• This disease is global (world-wide). People who
  get infected develop antibodies that can be
  detected by serological assays (special blood
  tests).
• By this means, it has been determined that about
  40 of the US population has been infected
  (serologic positive) for this disease.
• However, the symptoms are usually subclinical
  (mild or no symptoms).
• The exceptions to this are for those who are
  immunocompromised (HIV, infants, etc).

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TOXOPLASMOSIS

• MODES OF TRANSMISSION
• Fecal-oral The cat defecates and releases
  protozoa cysts. Humans ingest it after cleaning
  cat litter boxes. It only causes a problem in the
  fetus of a pregnant woman who cleans the cat
  litter box.
• Eating meat not fully cooked (tissue cyst). In
  France, it is common to eat raw meat, so the
  disease is more common there.
• Congenital transmission (fetus gets infected when
  mother gets the disease)

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TOXOPLASMOSIS

• GEOGRAPHIC DISTRIBUTION
• France (from eating raw meat)
• Central America (lots of stray cats)
• United States (pet cat eats a wild bird, pregnant
  woman cleans cat litter box, especially during
  first trimester)
• This organism prefers nerve tissue, so it travels
  to the CNS. In the fetus, it causes retinal
  damage (blindness), brain damage, hydrocephaly,
  and stillbirths. In other humans, it causes mild
  symptoms which go away, then white blood cells
  make antibodies that can be detected. Treatment
  is needed only for those who are
  immunocompromised (AIDS patients, etc).

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Toxoplasmosis
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TRYPANOSOMES

• Causative agent Trypanosoma
• Diseases
• African Trypanosomiasis (African Sleeping
  Sickness)
• American Trypanosomiasis (Chagas Disease)

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AFRICAN TRYPANOSOMIASIS

• The biological vector is the tsetse (pronounced
  set-see) fly. The tsetse fly bites a human and
  injects the protozoas into the skin. This causes
  a chanchre (pronounced shanker), which is an
  ulcer on the skin. Then it enters the lymph
  nodes. It is characterized by Winterbottoms
  Sign swelling of the cervical lymph nodes in the
  head and neck area.
• Central nervous system (CNS) symptoms include a
  shuffling gait (like a stroke victim), slurred
  speech, and malaise (needing to sleep longer and
  longer each day). They are also restless at night.

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Tsetse Fly
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Winterbottoms Sign
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AMERICAN TRYPANOSOMIASIS

• This disease is NOT found in Africa. The
  biological vector is a large bug called the
  Kissing Bug. It is found in warm regions and
  crowded areas, especially in the cracks of adobe
  huts. It comes out at night and crawls on a human
  while they sleep. It prefers the lips because the
  blood supply is close to the surface. It sucks
  the blood there, but they dont transmit the
  organism this way. When they suck the blood, they
  also defecate, and the organism is in the feces.
  When the human wakes up to scratch the itch,
  feces get into the tiny wound. This is a fecal?
  blood route.
• Symptoms include fever, anorexia, swollen lymph
  nodes, enlarged liver and spleen, and
  inflammation of the heart, which usually causes
  death.

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Trypanosoma cruzi

• Triatomine bug, Trypanosoma cruzi vector,
  defecating on the wound after taking a blood meal.

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Kissing Bug
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LEISHMANIASIS

• Organism Leishmania
• Disease Leishmaniasis
• Geographical Distribution tropic and subtropic
• Biological vector is a sandfly, which is quite
  small. It is smaller than a fruit fly, but larger
  than a mosquito.

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LEISHMANIASIS

• There are three forms of Leishmaniasis
• Cutaneous
• Mucocutaneous
• Visceral

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LEISHMANIASIS

• Cutaneous
• This is disease only at the site of the bite.
  This form is seen in Texas, Mexico, Asia, and the
  Middle East (our Iraq troops are coming down with
  this form). It manifests as a large, wet sore
  with raised edges. It looks like a volcano with
  weepy serum coming out of the center. The wound
  is not contagious, just the sandfly bite. Dogs
  can get this disease, too.

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Sandfly

• This looks like a mosquito, except its body is
  hairy and the wings are feathery.

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Leishmaniasis (cutaneous)
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LEISHMANIASIS

• Mucocutaneous
• This is disease located in the mucous membranes
  of the nose and mouth. The most gruesome photos
  are of this form.

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LEISHMANIASIS

• Visceral
• This is the most serious form known as Kala
  Azar.
• It occurs especially in immunocompromised people,
  especially HIV patients.
• In this form, the protozoa multiply in white
  blood cells as well as other organs including the
  spleen, liver, and lymph nodes. Symptoms fever,
  weight loss, and a decrease in all types of blood
  cells WBC, RBC, and platelets. The treatment is
  almost as bad as the disease because of the side
  effects. It is best to catch it early.

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