Protozoans

Protozoan Groups Apicomplexans Sarcodines Ciliates Flagellates Fig. 11.CO

Colonial Flagellates Fig. 11.30 Volvox colony

Protozoan Taxonomy Morphological taxonomy Molecular taxonomy Phylum sarcomastigophora Subphylum mastigophora Flagellates Phytoflagellates Zooflagellates Subphylum sarcodinia Amoebas Foramiferans Radiolarians Phylum Ciliophora Ciliates Phylum Apicomplexa parasitic protozoa Spore forming protozoans Molecular taxonomy Indicate that morphological relationships are tenuous Divergence between phyla of protozoa as great as between kingdoms (i.e. animalia, fungi and plantae) Revisions are continuously occurring

Basis of Taxonomy Morphological traits Reproductive modes Flagella Cilia Pseudopodia Shells (tests) Reproductive modes Sexual Asexual Spore formation Distinct reproductive cell forms Cyst formation Characteristic organelles Apical complex Kinetoplast Presence/Absence of mitochondria Trophism Heterotrophic Autotrophic

Flagella & Cilia Fig. 11.3a

Fig. 5.5, pg 89 Fig. 11.6b

Pseudopodial Movement Fig. 11.4

Amoeba Amoeboid movement Phagocytosis Pseudopodial extension Engulfment of large particles Fig. 11.5

Contractile Vacuoles Osmotic regulation Remove excess metabolic H2O, and HCO3 Remove H2O that enters by osmosis Refer to fig 5.7 Fig. 11.8

Feeding Fig 5.6, page 90 Fig. 11.9

Examples of Binary Fission – Asexual Reproduction Fig 5.8, page 91 Fig. 11.10

Radiolarian Undergoing Binary Fission Fig. 11.29

Sexual Reproduction Conjugation Sporogomy Meiotic nuclear division Transfer of portion of genome between partners Sporogomy Formation of sporozoites Formation of gametocytes from sporozoites Fusion of gametocytes to form new generation of sporozoite Gametocytes and sporozoites are present in separate hosts

Cell Specialization in the Colonial Volvacae Fig 5.11, page 93 Fig. 11.13

Reproduction in Ciliates – Sexual and Asexual Conjugation Fission Fig 5.18, pg 98 Fig 5.9, page 91 Fig. 11.23

Conjugation Fig. 11.23a

Conjugation Fig. 11.23c

Conjugation Fig. 11.23e

Cyst Formation Fig 5.1, page 85 Fig. 11.1

Taxonomy of Kingdom Protozoan

Phylogenic Distinctions Kingdom Protista Protozoans Kingdom Animalia Fig. 9.9a

Phyla Retortamonada and Axostylata Derived from an early ancestral eukaryote Retortamonada Lack both mitochondria and Golgi bodies. Include Giardia lambia – intestinal parasite, produces violent, but not fatal symptoms. Produces cyst that are passed by the host, host is infected by contaminated drinking water. Axostylata Have a stiffening rod, the axostyle, composed of microtubules that extend along the longitudinal axis. Members of the Order Trichomonadida contain hydrogenosomes, that function in the same method as mitochondria . Tichomonas vaginalis – sexually transmitted parasitic, causes urinary tract infections.

Phyla Retortamonada and Axostylata Giardia lambia Tichomonas vaginalis

Phylum Chlorophyta Plant-like Protozoan's Autotrophic, and contain one or more chloroplast (organelles that contain the pigment chlorophyll used for photosynthesis) Single celled algae such as Chlamydomonas Colonial organisms such as Gonium and Volvox

Phylum Euglenozoa A phytoflagellate Autotrophic Opportunistic heterotroph Contain a light sensitive organelle known as the Stigma. Kinetoplast, large disk of DNA contained in the mitochondria Major cause of parasitic infections throughout the world. Genus Trypanosoma Genus Leishmania Fig. 11.14

Immages from links at http://www.biosci.ohio-state.edu/~parasite Trypanosomiasis African sleeping sickness – Eastern hemisphere Trypanosoma brucei Vector – Tsetse Fly - Glossina spp Immages from links at http://www.biosci.ohio-state.edu/~parasite

Trypanosomiasis Chaga’s disease – Western hemisphere Trypanosoma cruzi Vector – assassin bug – Rhodnius spp, Panstrongylus spp and Triatoma spp

Life Cycle of Trypanosoma

Trypanosoma Early diagnosis – treatment very successful Suramine or Pentamidine depending on subspecies of trypanosome Late phase treatments Low success rate Serious side effects (including lethality) of drugs Melarsoprol – often causes sever allergic reaction which causes neural damage Eflornithine – only effective against gambiense subspecies and is no longer produced These drugs contain arsenic

Leishmania Leishmania donovani “referred to as Dum-Dum Fever or kala-azar” Spread by sand flies; phlebotomus spp. Common in Africa and India, and rare in the Mediterranean and Latin America. Causes fever, malaise, progressive wasting, anemia, lesions, enlargement of the liver and spleen, facial scarring and death.

Leishmaniasis Treatments – Antimony containing compounds meglumine antimonate sodium stibogluconate

Life Cycle of Leishmania

Phylum Apicomplexa Parasitic Reproduce both sexually and asexually Set of organelles called the Apical Complex Present in the sporozoite for invading the host cells Cilia, flagella or pseudopodia – but these are lacking in most species. Form spores Two main Classes Gregarinea – intestinal parasites, normally complete life cycle within one host. Coccidea – vertebrate parasites include; Cryptosporidium Toxoplasma Plasmodium – malaria 500 million cases annually 1-2 million deaths annually

Apical Organelles of the Apicomplexans Fig 5.13, page 95 Fig. 11.16

Life Cycle of Plasmodium falciparum Fig 5.14, page 96 Fig. 11.17

Phylum Ciliophora Large, diverse phyla Typically found in marine or freshwater environments Range in size from 10um to 3mm long and all have cilia during their life cycle Multinucleate Macronucleus – controls metabolism, synthesis of organic molecules and development of the organism Micronucleus – function in sexual reproduction and give rise to the macronucleus after sexual reproduction. Holozoic, feeds on organisms via a cytostome Defensive and predatory adaptations Trichocysts – defensive Toxocysts – toxic to paralyze prey Pellicle – protective coating that can range from a single cell in thickness to a thick armored covering

Phylum Ciliophora– Parmecium sp Fig 5.17, page 98 Fig. 11.20

Some other Ciliates Fig 5.15, pg 97 Fig. 11.24

Phylum Dinoflagellata Ecologically important Primary producers in marine environments – photosynthetic varieties Commonly have two flagella Either photosynthetic or herbivores Some species are bioluminescent Zooxanthellae gen. live in mutualistic relationships with other protozoans, sea anemones, coral and clams (ex. with stony coral which produces coral reefs) Some species are responsible for red tides Release toxins that paralyze or kill fish Protozoans then feed on fish Can affect humans be affecting the respiratory and nervous systems, as well as causing sores to develop.

Dinoflagellates Fig. 11.25

Amebas Fresh and salt water environments, and soil moisture Planktonic or substratum Holozoic Some parasitic species Entamoeba histolytica Brain infections Protective tests (or shells) form to protect the organisms Formaninferans – include sand into the test Radiolarians Marine, planktonic with siliceous skeletons Among the oldest known species of protozoans Common throughout the geologic or fossil record

Examples of Amebas Fig. 11.26