afl quiz 6

dinoflagellate thecal plates

forming the armor around the cell, each  consisting of cellulose within a membrane sac

dinoflagellate girdle

slight furrow running around the middle of the cell

dinoflagellate epicone

upper (anterior) half of the cell

dinoflagellate hypocone

bottom (posterior) half of the cell

dinoflagellate sulcus

slight depression running up the posterior half of the cell, ending at the middle of the cell

dinoflagellate transverse flagellum

flagellum that winds around the middle of the cell

dinoflagellate longitudinal flagellum

flagellum that sits in the furrow in the lower half of the cell, and sometimes gets extended beyond it to full length depending on how the cell is swimming

Many dinoflagellates have a chloroplast with three membranes.  (The third or outermost membrane is called “chloroplast ER” because it has ribosomes on it and so it functions as endoplasmic reticulum.) 

In MOST dinoflagellates with chloroplasts, where is that chloroplast thought to have come from? 

secondary endosymbiosis of a red alga chloroplast (leaving one layer of chloroplast ER)

In SOME dinoflagellates, that original chloroplast appears to have been lost and there is a new type of chloroplast.  Where is that new type of chloroplast thought to have come from?

a prymnesiophyte alga

What is the origin of each of the three membranes around the chloroplast? 

1)   Original bacteria cell wall

2)    Cell vacuole wall

3)    Secondary endosymbiosis absorbing red algae chloroplast created a third membrane that is the host cell’s phagocytic membrane

Do all dinoflagellates have chloroplasts?

no

Why would a dinoflagellate want to journey to the bottom of a pond or deeper into the ocean where there isn’t much light?  (Same reason as for cyanobacteria that travel down to the bottom at night - there's something down there that they need that is less abundant at the surface because there are so many algae at the surface)

nutrients

What two functions might the trichocyst perform in dinoflagellates?  (briefly explain them - no how does the trichocyst achieve each of the two objectives, at a level that your non-biologist friends could appreciate)

1) defense → spear enemies

2) movement → can run away from enemies

Name any TWO apparent historic occurrences of red tides and find a piece of decriptive information about it that we didn't include on the outline/powerpoint - anything you can locate in the textbook or online. 

1) one of the Egyptian plagues (Exodus) was apparently a red tide  the nile was described as “turning to blood”  

2) red tides witnessed by Darwin on the Beaglec.  Captains Cook and Vancouver learned of bioluminescent tides and mussel poisoning in Pacific Northwest  Darwin noted bioluminescent and red tides. Vancouver had crew get sick after eating mussles caught during a bioluminescent bloom (which the native people had taboos against) and Cook had crew get sick after eating freshly caught red fish. Both captains documented symptoms similar to those we know as belonging to toxic algae today.

How do shellfish "acquire" dinoflagellates, so that when you eat a shellfish, you eat the dinoflagellates too?  (It has to do with shellfish being filter-feeders, so they run a water current through a particular structure in their bodies and strain out food particles, including dinoflagellates)

Shellfish are filterfeeders, meaning they pull water in and strain out solids and unwanted particules, keeping them in their tissues

Where does diarretic shellfish poisoning show up – in the tropics or in temperate regions?

temperate regions

When humans get diarretic shellfish, what symptoms does it cause?

diarrhea, nausea, vomiting, abdominal pain, gastroenteritis

Ciguatera fish poisoning comes via shellfishes OR fish that eat seaweed.  How do they acquire the particular dinoflagellate that causes that kind of poisoning?

by a fourth, tropical genus of dinoflagellate which grows on seaweed. It gets eaten and passed through fish and shellfish to people who get extreme diarrhea

Where does ciguatera fish poisoning show up – in the tropics or in temperate regions?

tropics

When humans get ciguatera fish poisoning, what symptoms does it cause?

Nausea, vomiting, diarrhea, headache, dizziness, muscle aches, itching

In paralytic shellfish poisoning, the dinoflagellates involved produce a type of  neurotoxin. What does the neurotoxin do to action potentials?

Saxitoxin blocks voltage-gated sodium channels on nerve and muscle cells.

By blocking these channels, it prevents sodium ions from entering the cell during an action potential.

Without sodium influx, the nerve cannot depolarize, so action potentials are blocked.

This leads to failure of nerve signal transmission, causing paralysis.

Where does paralytic shellfish poisoning show up – in the tropics or in temperate regions?

temperate regions

When humans get paralytic shellfish poisoning, what symptoms does it cause?

Weakness, headache, nausea, vomting, paralysis

Have there been any recent instances of mussels or clams being over the limit in biotoxins?  Write down a date and a beach that was closed as of that date.

9/12 gold beach

From the section in Lee on dinoflagellates and oil and gas deposits, note the discussion of geological deposits in England that contain alternating layers of shale deposits and limestone.  Limestone is largely calcium carbonate, which can form from huge deposits of calcified algae such as coccolithophorids that we haven’t discussed yet.  The shale layers contain both coal and oil.

 

What is the evidence that dinoflagellates were the source of the oil in this particular rock?

Certain oil deposits were formed from dinoflagellate blooms, proven by the presence of certain 4alpha-methylsteroidal hydrocarbons apparently derived from 4alpha-methylsterols characteristically dominant in dinoflagellates (one of these is called “dinosterol”)

Some dinoflagellates are bioluminescent, and these can form blooms.  Depending on the type of dinoflagellate, luminescent blooms may be toxic or they may be nontoxic.  They are sometimes considered red tides.

First, understand what the textbook says in a general way about luciferin and luciferase on p. 274.  In bacteria, luciferin is a "reduced flavin."   In fireflies and other insects, luciferin is a (benzo)thiazole nucleus.  What type of chemical is the luciferin in dinoflagellates?

tetrapyrrole

Two hypotheses have been proposed for why some species of dinoflagellates produce bioluminescence:  The “Burglar Alarm” hypothesis and the “Startle” hypothesis.  What are these two hypotheses?  Briefly explain them.

burglar alarm hypothesis:  to attract predators of copepods and other things that eat them

   startle hypothesis: to startle copepods and other predators, causing them to swim away

Name any three different activities that dinoflagellates do that show a circadian rhythm.

1) It produces light via bioluminescence

2) photosynthesis occurs in a cycle (most occurring during the peak of the day)

3) cell division occurs all at once

4) vertical water column migration  

What are the four feeding strategies that dinoflagellates use when they engage in heterotrophic nutrition (eating), which they can do instead of, or in addition to, photosynthesis? Briefly describe each in a sentence or so.

1)    Direct engulfment of prey → tentacle captures prey and brings it to the oral pouch

a.     Can also be via a nematocyst (tether prejection)

2)    Pallium feeding → feeding veil (pallium) emerges and encloses around the prey where digestive enzymes begin to break it down

3)    Peduncle → projection of cytoplasm, makes a hole in the prey, sucks nutrients out, then retracts

When dinoflagellates live inside corals, they are called “zooxanthellae,” which translates to “mobile flagellated yellowish things”. What do they give the coral and what do they get in return?

Give the coral carbon, coral gives amino acid taurine

To finish out the dinoflagellates, on Monday we are looking briefly at several articles on Pfeisteria piscicida.  What does this dinoflagellate do to fish that justifies its scientific name?  How does a single-celled creature manage to do this to fish?

They are able to chemically detect, ambush, then immobilize and kill prey (via toxins). The toxins destroy the flesh of the prey, allowing the dinoflagellates to access nutrients and consume the prey.

The 1996 article by the Burkholder lab does three taxonomic things. What are those three things?

1) puts the pfiesteria piscicida into the order Dinamoebales

2) creates a new genus: pfiesteria

3) creates a new species: pfiesteria piscida

List the algae phyla that we’ve covered so far (five through the Dinophyta).  Then, check with your lec 12 outline or powerpoint to see if you remembered correctly.

1)    Cyanophyta

2)    Rhodophyta

3)    Chlorophyta

4)    Euglenophyta

5)    Dinophyta

6)    Apicomplexa

7)    Chlorachniophyta

8)    Cryptophyte

9)    Heterokontophyte

10) Prymnesiophta

Phylum #6, the Apicomplexa, includes the malarial parasite Plasmodium.  Members of this phylum have what your textbook describes as “reduced colorless plastids.”  What are those “reduced colorless plastids" now thought to be, as a result of molecular studies?   (NOTE: this is why they are “algae” – at one point they were photosynthetic)

chloroplast

Phylum #7, the Chlorachniophyta, are amoeba-like unicellular algae that look like which of the following?

green spiders