An Overview of Parasite Diversity - Vocabulary Flashcards

Vocabulary flashcards covering parasite diversity, species concepts, taxonomy, organelles, evolutionary principles, and key organismal examples from Chapter 2.

Biological species concept

A concept defining a species as a group of individuals with similar properties that interbreed and produce fertile offspring, which cannot be readily applied to parasites that rarely undergo sexual reproduction.

Evolutionary species concept

A species concept defining a species as a single lineage with a shared evolutionary trajectory.

Nanoarchaeum equitans

A species of Archaea known to parasitize another Archaea species, representing a rare occurrence of parasitism in Archaea.

Holospora

A genus of parasitic bacteria that infects Paramecium and causes host castration.

Legionella pneumophila

A parasitic bacterium that hides inside freshwater amoebae.

Kinetoplast

A specialized structure in excavates such as Trypanosoma that contains DNA similar to mitochondrial DNA.

Giardia

A diplomonad parasite possessing central and peripheral mitosomes, two nuclei, an adhesive disc, a median body, and multiple flagella.

Trichomonas vaginalis

A parabasalid parasite possessing hydrogenosomes (modified mitochondria), anterior flagella, an axostyle, a costa, and an undulating membrane.

Phytophthora infestans

An oomycete fungus-like microorganism responsible for the Irish potato famine that utilized horizontal gene transfer to acquire nutrients and resist host immune defenses.

Apicomplexa

A nearly exclusive group of intracellular parasites characterized by an apical complex containing a conoid, rhoptries, polar rings, and apicoplasts.

Conoid

An organelle in Apicomplexans consisting of microtubules arranged in a spiral configuration.

Rhoptries

Secretory organelles located within the apical complex of Apicomplexan parasites.

Apicoplast

A relict organelle in Apicomplexa bounded by four membranes that contains a circular genome derived from an algal or cyanobacterial endosymbiont and has lost its photosynthetic ability.

Toxoplasma gondii tachyzoite

An intracellular apicomplexan cell stage containing an apical polar ring, conoid, micronemes, rhoptries, dense granules, subpellicular microtubules, and an apicoplast.

Mycology

The scientific study of fungi, including parasitic species.

Chitin

A polymer of $\text{N-acetyl-glucosamine}$ that forms the cell wall of fungi.

Pneumocystis jirovecii

An Ascomycota fungus that acts as an opportunistic parasite causing pneumonia in humans.

Heirloom parasite

A parasite that has co-evolved with its host lineage from an ancestral species, such as Pediculus humanus in humans.

Souvenir parasite

A parasite acquired by a host species via host-switching from a different lineage, such as Pthirus pubis acquired by humans from gorillas.

DNA barcoding

A technique used primarily to identify new species by sequencing the cytochrome oxidase 1 (CO1) gene of mitochondrial DNA.

Cytochrome oxidase 1 (CO1)

A mitochondrial gene prone to mutations caused by reactive oxygen species, used extensively in DNA barcoding.

Cryptic species

Organisms that are closely related and morphologically similar enough to be classified as a single species until genetic analysis reveals them as distinct.

Isolate

A sample of a parasite derived directly from a specific individual host or patient.

Strain

Intraspecific genetic variations or subtypes identified within a single parasite species.

Subspecies

An intraspecific group occupying distinct geographic regions that remains capable of interbreeding with other subspecies of the same species.

Dollo's law

The evolutionary hypothesis stating that the transition to parasitism is a one-way trajectory involving gene loss.