Viruses, Protists Part Iii)

Part III: Protistans Differ from Prokaryotes  Have a nucleus and organelles  Have proteins associated with DNA  Use microtubules in a cytoskeleton,

spindle apparatus, and cilia and flagella  May contain chloroplasts  May divide by mitosis and meiosis

Major Lineages Heterotrophs  

Protozoans Sporozoans

Autotrophs   

Green algae Golden algae Diatoms

Mix or Both 

Euglenoids



Dinoflagellate

Animal-Like Protistans  Informally known as protozoans  May resemble single-celled

heterotrophic protistans that gave rise to animals  Include predators, parasites, and grazers

Major Groups of Protozoans  Sarcodina - Amoeboid protozoans  Ciliphora - Ciliated protozoans  Mastigophora - Animal-like flagellates 

Sporozoans - Parasitic heterotrophs

Answer 26  26. Protistans differ from prokaryotes.  State two differences:  Protistans have: a membrance bound

nucleus; organelles such as mitochondria, chloroplasts; microtubules; mitosis and meiosis  Prokaryotes lack these structures.

Answer 27  27. Animal-like protistans are informally

known as:  Protozoa

Answer 28  28. Which of the following is (are)

mismatched?  Sarcodina – amoeboid protozoans  Ciliophora – parasitic heterotrophs such as

sporazoans  Mastigophora – animal-like flagellates

Naked Amoebas  Change shape constantly  Move by means of pseudopods  Most are free-living cells that engulf

their prey  Some are symbionts in animal guts  A few are opportunistic pathogens

Florida Boy Dies From Amoeba Infection In Brain (CNN) -- An unidentified 12-year-old died Friday after being infected with an amoeba while swimming in a Florida lake. The boy had meningeal encephalitis -- a combination of meningitis and encephalitis, which causes the brain to swell, according to Dr. Jaime Carrizosa, an infectious disease specialist from Florida Hospital in Orlando. Carrizosa had treated the boy. http://www.rense.com/general27/oom.htm

Other Ameboid Protozoans  Foraminiferans 

Calcium carbonate shell

 Radiolarians and Heliozoans 

Shells of silica

Question 29  29. Amoeba move by means of

cilia/pseudopods/flagella. (Choose one)

Answer 29  29. Amoeba move by means of

cilia/pseudopods/flagella. (Choose one)

Answer 30  30. “Shelled” Amoebas have “houses”

made from silica/calcium carbonate/ or some silica and others calcium carbonate. (choose one)

Answer 31  31. True/false. All amoebas are free-living;

none are parasitic. (If false, give a counter example)  False. Some freshwater types can invade the brain and cause death. Others are internal parasites.

Ciliated Protozoans 

Phylum Ciliphora



All heterotrophs



Arrays of cilia allow movement and direct food into oral cavity

Hypotrich

Ciliate Conjugation  Most ciliates have two different nuclei 

Large macronucleus



Smaller micronucleus

 Micronucleus participates in sexual

reproduction (conjugation) 

Partners exchange micronuclei

Answer 32  32. What is name for the phylum which

contains ciliates such as Paramecium?  Ciliophora

Answer 33  33. Ciliates have two types of nuclei.

Name them.  Macronuclei and micronuclei

Answer 34  34. What is the name for the process

where ciliates exchange micronuclei?  conjugation

Answer 35  35. Ciliates use cilia for both locomotion

and feeding.

Animal-Like Flagellates  Phylum Mastigophora  Move by means of flagella  All are heterotrophs 

Free-living species in freshwater and marine habitats



Many are internal parasites



Stopped here 2/28/2007

Body Plan of a Trypanosome (Causes African Sleeping Sickness) Undulating membrane

mitochondrion

free flagellum nucleus

basal body of flagellum

Trichomonas vaginalis (Common STD)

Trichomonas vaginalis 

“Trichomonas vaginalis is a sexually transmitted disease (STD), although transmission by other routes (such as soiled towels) has been documented. 



  Most people infected with trichomoniasis are asymptomatic. 



Symptomatic infections are characterized by a white discharge from the genital tract and itching.” 



Red Tide Toxins Can Cause Respiratory Problems in Humans

Source: Boston Globe, 3/29/05

Answer 36  36. Animal-like flagellates belong to the

phylum Mastigophora.

Answer 37  37. Name two flagellates that may cause

health or environmental problems.  Trypanosomes, Trichamonas, and /or

dinoflagellates (red tide organisms)

Sporozoans  Parasitic  Complete part of the life cycle inside

specific cells of a host organism  Many have elaborate life cycles that

require different hosts  Many cause serious human disease

Cryptosporidium 

Motile infective stage (sporozoite) invades intestinal epithelium



Causes cramps, watery diarrhea

 Commonly transmitted by

water contaminated with cysts

Cryptosporidium sp 

“Cryptosporidium sp. could occur, theoretically, on any food touched by a contaminated food handler. Incidence is higher in child day care centers that serve food. Fertilizing salad vegetables with manure is another possible source of human infection. Large outbreaks are associated with contaminated water supplies. Relative Frequency of Disease: Direct human surveys indicate a prevalence of about 2% of the population in North America. Serological surveys indicate that 80% of the population has had cryptosporidiosis. The extent of illness associated with reactive sera is not known.” http://vm.cfsan.fda.gov/~mow/chap24.html

Toxoplasma  Cysts may be ingested with raw or

undercooked meat  Exposure to cysts from cat feces  Symptoms are usually mild in people with normal immune function  Infection during pregnancy can kill or damage the embryo

Study Links Parasites In Freshwater Runoff To Sea Otter Deaths  “Science Daily — In recent years, wildlife veterinarians

have become concerned about the increasing number of southern sea otters dying in California. The current otter population is 10 percent lower than it was in 1995. Disease has been identified as one reason. Two species of protozoa, Toxoplasma gondii and Sarcocystis neurona, have been identified as

important causes of fatal brain infections in these otters. “

 Note: Cat feces from freshwater runoff

linked to infections!

http://www.sciencedaily.com/releases/2002/06/020627004404.htm

Malaria  Symptoms have been known for more

than 2,000 years  Most prevalent in tropical and

subtropical parts of Africa  Kills a million Africans each year  Caused by four species of Plasmodium  Transmitted by Anopheles mosquitoes

Baghdad Boil' Afflicting U.S. Troops  Sun Apr 18, 5:36 PM ET By STEPHEN

MANNING, Associated Press Writer  “WASHINGTON - Staff Sgt. Eric DiVona didn't notice the small bumps on his face and left earlobe until he returned from serving nine months in Iraq (news - web sites). Nothing much, he thought, probably just a spider bite.”

In the News: “Baghdad Boils”  “Leishmaniasis is a disease caused by the

protozoa of the Leishmania species, which is transmitted by the bite of a female sandfly.  leishmaniasis is classified as cutaneous, mucocutaneous, and visceral leishmaniasis.”

LEISHMANIA (Sporazoan)     4 PATHOGENIC SPECIES     INFECTION OCCURS FROM INJECTION OF THE LARVAE FROM AN  INFECTED SANDFLY- THE INTERMEDIATE HOST PHAGOCYTIC CELLS INGEST THE PARASITE BUT CANNOT KILL THEM SANDFLY INGESTS THE PARASITE FROM DOGS

“Dogs are considered the major reservoir for human disease.”

Answer 38  38. All of these organisms are parasitic.

There are many different species including the malarial organisms. sporazoans

Answer 39  39. Why should pregnant women avoid

contact with cats? Cats are vectors of the sporazoan, Toxaplasma. Infection of pregnant women can cause harm or even death to the fetus.

Answer 40  40. What is the vector of the malarial

organism? Female mosquitoes

Euglenoids  Phylum Euglenophyta  Free-living flagellated cells that live in

freshwater  Majority are photoautotrophs  Some are heterotrophs that feed on dissolved organic compounds  Sewage pollution indicator organisms

Euglenoid Body Plan (Refer to text)

long flagellum chloroplast

eyespot shielding a ER light-sensitive receptor nucleus Golgi body

mitochondrion pellicle

Chrysophytes  Phylum Chrysophyta  Mainly free-living photosynthetic cells  Four groups:

- Golden algae

- Diatoms

- Yellow-green algae

- Coccolithophores

Diatom Characteristics  Cell wall is composed of silica  Two valves (halves) similar to a Petri dish  Golden/green in color  Important primary producers in both

marine and freshwater ecosystems

Green Algae  Phylum  7,000

Chlorophyta

species

 Resemble

plants



Chlorophylls a and b



Starch grains in chloroplasts



Cell walls of cellulose, pectins

Ulva

Chlamydomonas Life Cycle (Refer to text for graphic) Zygote

Nuclear fusion

Diploid

Meiosis, germination

Haploid

Mitosis Cytoplasmic fusion

Asexual reproduction

Sexual reproduction Gametes meet

Asexual reproduction

Answer 41  41. To what phylum do Euglena and its

relatives belong?  Euglenophyta

Answer 42  42. What type of algae live in “glass

houses” and are important primary producers?  diatoms

Answer 43  43. What major group (phyla) of algae

most closely resemble green plants?  Green algae (Chlorophyta)