HC 13: Soil protists

protists

single cell eukaryotes, formally called protozoa

• feed on other microbes like bacteria or fungi.

What can protists do (predators) in the soil

they mostly eat bacteria.

Some of the nutrients that are locked in the bacteria will be released thanks to the predation by the protists —> can be used by other bacteria, or they can be taken up by mycorrhizal fungi and brought to the plant root, or directly taken up by the plant.

• This way protists help plants.

Do protists eat everything?

No. they are picky.

• They do selective feeding.

• When bacteria is too big, they wont be eaten, with the exception of pack hunting (like how they eat nematodes).

• When bacteria are to fast, they wont be eaten as well.

• Biofilm can also protect bacteria and their friends. Bacteria can also defend themselves with secondary metabolites

Understanding of the hurdles and difficulties of studying protists

-      Het merendeel is niet kweekbaar onder standaard laboratoriumcondities

-      bekijken via microscopie is vaak lastig (vooral bij lage abundance zoals Artische gebieden), omdat de soorten erg klein zijn en in lage concentraties voorkomen

-      Vanwege deze problemen maken onderzoekers soms gebruik van indicatorpigmenten (bijv. chlorofyl) om de aanwezigheid van specifieke families te bepalen zonder de cellen direct te hoeven zien of kweken