protozoans

general characteristics of protozoans

eukaryotes

unicellular

no CW but with CM

motile

heterotrophic

heterotrophic

organisms that obtain nutrients by consuming other organic matter

by phagocytosis and pinocytosis

what are their symbiotic relationships

parasitic and mutualistc

where to they live

in aquatic and terrestrial areas including freshwater, marine, and soil environments.

trophozoite

the active, feeding stage of protozoans — vegetative

cyst

a dormant, resistant stage that protects protozoans during adverse environmental conditions.

pellicle

plasma membrane where cilia are attached

ectoplasm

gelatinous cytoplasm for rigidity

endoplasm

within the ectoplasm with most of the or

mmacronucleus

for somatic functions of the protozoa

• locomotion

• feeding

• osmoregulation

  • cell regeneration

micronucleus

for sexual reproduction and regeneration of macronucleus

3 types of vacuoles

secretory vacuoles — has enzymes

phagocytic vacuoles — for digestion

contractile vacuoles — excretion, osmoregulation, and water balance

locomotory organelles

pseudopodia (false feet)

flagella

cilia sh

shells in protozinas

calcareous - in foraminiferans

silliceous - in radiolarians

• chert

types of nutrition

holozoic - phagocytosis

saprozoic - nutrients cross plasma membranes

type of sexual reproduction

conjugation

types of asexual reproduction

simple fission

longitudinal fission

transverse fission

multiple fission

representative organism of amoebae

entamoeba hystolytica

what are the virulence determinants of e. hystolytica

ADHESION - lectin, lipophosphoglycan, lipid rafts

INVASION - cysteine proteases, phospholipases

EVASION - phagocytosis, apoptosis induction, complement resistance

TOXICITY - amoebapores

what causes chagas disease

Trypanosoma cruzi

primary reservoir of Trypanosoma cruzi

opossums and armadillos

virulence determinants of Trypanosoma cruzi

Adhesion: Trans-sialidases, Mucin-like glycoproteins, Heparan sulfate proteoglycans

Invasion: Antigenic variation, Motility, Parasite-induced endocytosis

Evasion: Antigenic variation, Intracellular survival, Immunosuppression

Toxicity: Release of cytotoxic molecules (proteases and glycosidases), Inflammatory response (induction of pro- and antiinflammatory cytokines)

Others: Immunomodulation, Host cell remodeling

chagas disease causes

congestive heart failure with formation of pseudocyts

causative agent of AFRICAN SLEEPING SICKNESS

Trypanosoma brucei

Insect vector of ASS

tsetse fly (Glossina species)

Virulence determinants of trypanosoma brucei

Adhesion: Variant surface glycoproteins

Invasion: Motility, Receptor-mediated endocytosis, Antigenic

variation

Evasion: Antigenic variation, Immunosuppression, Immune complex

formation (VSGs x host AGs)

Toxicity: Cytokine release, RBC lysis, Inflammatory response

disease caused by sand fly mites

Leishmaniasis

causative agent of leishmaniasis

Leishmania parasites

virulence determinants of Leishmania donovani

Adhesion: Leishmanolysin, Lipophosphoglycan (LPG)

Invasion: LPG, GP63

Evasion: Resistance to oxidative burst, Immunosuppression, Host cytokine modulation

Toxicity: Downregulation of antigen presentation and MHC II expression, Apoptosis induction

causative agent of giardiasis

Giardia lamblia

virulence determinants of giardia lamblia

Adhesion: Ventral adhesive disc, surface lectins, Flagella,

Phospholipases

Invasion: N/A

Evasion: Antigenic variation, Inhibition of host immune responses,

Cysteine proteases

Toxicity: Epithelial cell apoptosis, Disruption of nutrient absorption,

Induction of inflammation

what protozoan has no cyst stage

trichomonas vaginalis

virulence determinants of trichomonas vaginalis

Adhesion: Adhesins, LPGs, Surface lectins, Flagella

Invasion: N/A

Evasion: Antigenic variation, Cysteine proteases, Immunomodulation

Toxicity: Cysteine proteases, Pore-forming proteins, Hemolysins Others: Biofilm formation, Hydrogenosomes

what organ gets invaded by Balantidium coli

The large intestine, specifically the colon.

virulence determinants of balantidium coli

Adhesion: Cilia-associated motility, Surface lectin-like molecules

Invasion: Cysteine proteases, Active penetration

Evasion: Pellicle, Antigen masking/shedding

Toxicity: Lytic enzymes, mucosal ulceration, Inflammatory response

Others: Cyst formation, Replicative rate, Commensal to pathogen shift

causative agent of malaria

plasmodiumspecies transmitted by Anopheles mosquitoes.

life stages of plasmodium

sporogonic

exoerythrocytic phase

erythrocytic phase

virulence factors of plasmodium

Adhesion: Species-specific membrane protein (Allows clearance avoidance), Thrombospondin-Related Anonymous Protein (Sporozoites to Hepatocytes), Apical Membrane Antigen 1 (Merozoites and RBCs)

Invasion: Merozoite surface proteins, Apical organelles, Rhoptry neck proteins

Evasion: Antigenic variation, Cell adherence and Rosette formation, Immunosuppression

Toxicity: Hg degradation → Heme, Cytokine storm

Others: Sporozoite motility, Dormancy

causative agent of toxoplasmosis

Toxoplasma gondii

how is toxoplasmosis contracted

undercooked meat with aprasite

definitive host of toxoplasma

cats

Adhesion: Microneme proteins, Surface antigens

Invasion: Apical complex, Apical membrane antigen 1

Evasion: Intracellular lifestyle, Antigenic variation, GRA proteins

Toxicity: Tissue destruction

Others: Stage conversion, transmissibility

causative agent of cryptosporidiosis

Cryptosporidium parvum

cryptosporidium can be an indicator of what infection

AIDS

3 groups of helminths

cestodes
trematodes

nematodes

are the three major classifications of parasitic worms.

blood flukes

schistosoma

principal host of schistosoma

humans, where the adult worms reside and reproduce

where do blood flukes mate

circulatory system of their principal host, allowing them to reproduce.

how are blood flukes contracted

contaminated water