cryptomonads Flashcards
crytpo
hidden reflects uncertain phylogeny
some taxa can form reversible sessile and encapsulated stages
nonmotile and palmelloid
periplast
proteinaceous plates associated with inner side of cell membrane, separated by ejectosomes
ecjotosomes
Ejectosomes are projectiles, usually of two types: large (20 μm when discharged) or small (4 μm when discharged)
Long tapered ribbon, tightly spiraled and enclosed in single membrane
Discharged explosively when cell is disturbed, like a party favour
Thought to serve as defense or escape mechanism
4 membraned
nucleomorph b/w inner and outer membranes of chloroplast is remnant of its nucleus
colours
olive green, brown, blue-green, red
asexual
mitosis and cytokinesis
sexual
Isogamous with vegetative cells acting as gametes
Gametes fuse to form quadriflagellate zygote which divides by meiosis to form haploid vegetative cells
Haplontic lifecycle
some species produce
cysts or palmelloid stages
order goniomondales
colourless cells no plastids (no nucleomorph)
cryptomondales
red cells with phycoerythrin
chroomonadales
blue green cells with chloroplases containing phycocyanin
Mostly phytoplanktonic, sometimes dominant
component of spring bloom, in cold or deep water
Maximum abundance in oligotrophic, temperate, high- latitude lakes (e.g., dominant in Antarctic lakes)
High quality food for zooplankton (no toxins)
Light sensitivity may explain occurrence in deep water
Kleptoplastidy
cryptomonad chloroplasts ingested by ciliates and dinoflagellates remain functional, producing starch, for several days
Helps in survival of ichthyotoxic Pfiesteria zoospores
cryptomonads sometimes common where organic matter content is high
(probably due to facultative phagotrophy)
