Human Parasitology Exam 1 - M1-3

Hydrogenosome

Double membrane organelle in trichomonas parasites that performs anaerobic respiration with H+ as acceptor. Has hydrogenase which reoxidizes ferredoxin. ATP and acetate are produced as products

→ TRICHOMONAS

Metronidazole

Drug used to treat anaerobic parasitic infections (E. histolytica, G. lambila, and Trichomonas) that produces a toxic intermediate that destroys DNA and other macromolecules.

→ Activated by ferrodoxin-like flavo proteins or flavoprotein-like proteins

→ Reacts by maintaining the proton gradient that drives the drug’s uptake

Syngamy

Union of the enter cell when gametes fuse. Occurs in plasmodium

Pseudopod

Temporary arm-like projection of cell membrane that is filled with cytoplasm. Consist of actin filaments and may also contain microtubules and intermediate filaments

→ in ameabos

Plasmalemma (pellicle)

Thin Plasma Membrane found in mosts parasites. Also known as the ectoderm or outer membrane

Microtubules in the membrane

Found in the outer membrane and in most of the cytoskeleton. Helps provide structural support

Ectoplasm/Endoplasm

Type of cytoplasm found out and in organelles respectively.

Cytosome

The “cell mouth”. Found in balantidium. Specialized for phagocytosis, usually in the form of a microtubule-supported funnel or groove.

Contractile Vacuoles

Vacuoles seen in bacteria and other host cells. In Sarcodina and ciliates. Involved in water regulation.

Structures that mediate cell movement (3)

Flagella, Cilia, Pseudopodium

Flagella

Structure that mediates movement

May form auxiliary membrane attached to cell or are free standing structures on cell surface. Found in trypanosomes and giardia

Flagellum/Cilia

Structure that mediates movement

Both have same composition and are continuous with the PM. Have tube with 9 doublets of microtubules and basal body. Radial spokes connect doublets while diene arms extend from the tubules.

4 Types of Pseudopodia

1 Filopodia 2 Lubopodia 3 Rhizopodia 4 Axopodia

Axostyle

Supplementary structure embeded along the longitudinal axis of the cytoplasm (some flagellates)

Costa

Rod-like structure that runs along the base of the undulating membrane

Pelta

Crescent shaped membrane in some flagellates (Trichomonas)

Cyts Functions (3)

1 Protect against unfavorable conditions

2 Site for morphogenesis and nuclear division

3 Infective or transmissible form

Vesicular Nucleus

Nucleoli-like body called the Karyosome that lacks DNA and is present in parasidic amoeba (like entamoeba histolytica). DNA is contained in ant compartments and has scattered chromatin inside

Compact Nucleus

Densely packed chromatin in nucleus, similar to higher order eukaryotes. In genus balantidium/ciliates

Major groups of E parasites (3)

Protozoa, Trematodes (Cestodes), Nematodes

Cyst Functions (3)

1 Protect against unfavorable external conditions

2 Site for morphogenesis and nucellar division

3 Invective or transmissible form

Vesicular Nucleus

Nucelli-like body with karyosomes that lack DNA. In parasitic amoeba, contains DNA in anticomplexans. Has scattered chromatin inside

→ Entamoeba histolytica

Compact nucleus

Densely packed chromatin, similar to structures in higher eukaryotes. Ciliates have macronucleus and micronucleus

→ genus Balantidium

Fission

Division that follows a sequence. 1 Organelles 2 Nucleus 3 Cytoplasm

Binary Fission

fission where each parent gives rise to two progeny and may result in Endodyogeny or schizogony

Endodyogeny

Type of binary fission where two daughter cells are produced inside of a mother cell.

→ Toxoplasma.

Schizogeny

Rapid organelle and nuclear divisions occur peripherally. Cytoplasm segments to form separate organism called Merozoites. Multinucleated cell is called the Schizoint or segmenter

→ Plasmodium

Conjugation

Type of sexual reproduction where specialized cellular reproduction involving nucellar exchange and union

→ ciliates

Syngamy

Type of sexual reproduction where union of the entire cell where gametes fuse

→ Plasmodium

Serology

Type of diagnosis technique where anti-amoebic antibodies are detected in the blood or serum or feces. (typically only works of the parasite has entered the blood stream)

Hyperplasia

Disease where excessive cell replication thickens cell mucosa

→ E. histolytica

Amebic Liver Abscesses

Where trophozoite cells destroy hepatic (liver) cells. Carriers can be asymptomatic to this.

→ E. histolytica

Pulmonary Amebiasis

When trophozoites travel from liver to lungs and destroy lung cells.

→ E. histolytica

Brain Abscess

When trophozoite cells make their way to the brain and destroy brain cells

→ E. histolytica

genitourinary amoebiasis

RARE - infection of the kidneys, bladder, or genitalia

→ E. histolytica

Galactose-N-acetylglucosamine (Gal-NAc) BINDING LECTIN

Lectin expressed on the surface of some parasites (E. histolytica) that make parasites more mobile when they contact epithelial cells.

-triggers epithelial cell death from amoebic cytotoxicity

-Only in pathogenic species

-Leads to recruitment of neutrophils (further destroys colonic mucosa)

Gal-NAc

terminal carbohydrate forming the antigen of blood group A in HUMAN CELLS.

-involved in cellular communication

-Extra exposure can inhibit endocytosis

Transmembrane proteins OR GpI-anchored proteins

Surface proteins that mediate pathogenies by targeting cell lysis acter direct contact with epithelial cells.

-EX: galactose / N-acetyl galactose inhibitor lectin

Amoebapores

Ionophore-Like proteins that induce pore-formation in neutrophils and epithelial cells. Released from intracellular vesicles controlling other mediators (like cytosol prokinase)

Cysteine proteases

Proteins released by trophozoites that cleave host cell proteins

Acid phosphatases

Proteins released by trophozoites that target host cell phospho-proteins (like SAP and MAP)

Primary amebic meningoencephalitis

Brian infection that causes headaches, fever, and stiff neck (typical meningitis sympotoms)

Short incubation of 5-7 days

→ Naeglaria flowery

Amebostomes

specialized sucker-like appendages that nibble away at host cells. Known to release proteolytic enzymes.

→ Naegleria fowleri

Acanthopodia

Pointed pseudopodia expressed in Acanthamoeba trophozoites

Acanthamoeba Keratitis

RARE eye infection of the cornea caused by a microscopic, free-living single-celled amoeba

→ acanthamoeba

Granulomatous amoebic encephalitis

life-threatening central nervous system (CNS) infection caused by exposure of amoeba through skin contact

→ Acanthamoeba

IgA in parasitic infections

IgA mediates some cellular response to parasitic infections like Giardia. IgA is secreted and translocate through intestinal lumen when its produced by Intestinal Epithelial cells

-IgA is gut antibody isotype

-Expression activated when alert cells release cytokines and L6

Lamina Propria

Thin layer of connective tissue that forms part of the moist linings known as mucous membranes or mucosae, which line various tubes in the body (Gastrointestinal tract)

Nitric Oxide and Antimicrobial peptides

Molecules released by cells to help mediate response to giardia

IgA Protease

Proteases released by Giardia to help deal with host antibodies

CD59-like molecules

Molecules expressed on the surface of E. histolytica that disguise them as human WBC/H-cells

Variable surface proteins

Allow cells to vary their response to antigens and avoid existing antibodies and respond to immune pressure/secretions

-Giardia

Giardia Arginine Consumption

Giardia consume/compete for Arg with host in Jejunum

-Arg enduces encystation

-Arg needed for giardia cell wall

-Arg needed in host to make NO

Trichomonas vaginalis immune resistance

Trichomonas resists host immune response of complement and neutrophils. resists Neutrophil oxidative burst and results in vaginal disharge, vuvovial soreness and irritation

Dysuria

Swelling of the male prostate gland

→ Trichomonas vaginalis

Gestational trichomoniasis

Vaginal Emphysematosa

gas-filled pockets to form in the walls of the vagina

→ trichomonas vaginalis

metronidazole

Drug to treat anaerobic parasites: E. histolytica, G. lambila, Trichomonas

Activated when reduced by FERRODOXIN-like proteins or flavoprotein-like proteins. Produces a toxic intermediate and maintains a electrochemical gradient by this reduction that drives more drug uptake

Balantidal dysentery

acute or chronic gastrointestinal illness caused by Balantidium coli which causes Intermittent watery diarrhea with blood or mucus in stool