Ecología de protozoarios

Prof. Ana A. Huamantinco

2008

Importancia

• Rol en el medio natural– Depósitos de carbonato de calcio– Actividad fotosintética para generar O2 y O3

Distribución

• Factores:– Abióticos– Bióticos

Factores abióticos

• Regulan la presencia de protozoarios– Agua– Temperatura

• Rango 0-40 C• Crecimiento optimo a elevadas temperaturas

– Oxigeno

• Dunaliella

• Euglena sanguinea

Factores abióticos

• Oxigeno– Protozoarios que albergan bacterias

metanogénicas– Albergan algas unicelulares– Migración vertical

• Saprodinium sp.

• Paramecium bursaria y Stentor Chlorella

Factores bióticos

• Relación depredador-presa• Escasez de alimento:

– Formación de quistes– Cambio de forma– Inmovilización– Canibalismo

• Relación depredador-presa

• Etapa de palmela en Euglena

• Giant cannibalistic protozoon, a hypotrichous ciliate (Onychodromus quadricornutus), caught in act of devouring one of its small congeners (latter still visible on floor of gaping oral opening of the hunter). The predator has also sprouted spurs on its rear dorsal surface (a phenotypic change as defense/protection from still larger carnivores in its habitat) in response to a chemical signal emitted from its foes. [SEM kindly provided to the author (with permission to use at any time), some years ago, by protistological colleague Barry Wicklow, Saint Anselm College, Manchester, NH, USA.]

Simbiosis y parasitismo

• Protozoarios como comensales– Sinforismo– Ciliados en rumiantes

• Protozoarios como simbiontes– Flagelados en intestino de termites y

cucarachas– Dinoflagelados=zooxantelas y corales

• Sinforismo. Peritrichidos en ninfa de Odonata

• Ciliado Peritrichido sobre larva de Diptero

• Eudiplodinium negelectum (typically 80 um). Comensal en rumiantes.• The macronucleus (pink) and micronucleus (red) are visible, along with two extruded

zones of cilia, beating so they appear blurred, the skeletal plate (blue) and ingested plant fragments (yellow).

• Trichonympha sp. simbionte en termites

• Relación zooxantela y coral

Simbiosis y parasitismo

• Protozoarios como parásitos– Agentes patógenos fueron de vida libre– Especies anfizoicas– Protozoarios parásitos oportunistas– Variabilidad antigénica

• Oocysts of Cryptosporidium parvum labeled in an indirect immunofluorescence

Simbiosis y parasitismo

• Protozoarios como hospederos– Chlorella en ciliados– Partículas kappa (bacterias) en Paramecium

aurelia– Bacterias extracelulares en Joenia

• Bacterias en superficie de Joenia

• Pelomyxa y sus bacterias simbióticas

• Mixotricha paradoxa

Biogeografía de protozoarios

• Protozoarios de vida libre• Protozoarios parásitos• Mecanismos para la diseminación

• Figs 9-13. Endemic soil ciliates in the scanning electron microscope (from Foissner 1993, 2005). 9 - Bresslauides discoideus is a massive, up• to 600 μm-sized “flagship” occurring only in Laurasia and the transition zone to Gondwana (Fig. 19). With its large, table-like mouth, it can feed• even on rotifers; 10 - Cosmocolpoda naschbergeri, although being only up to 70 μm long, is also eye-catching because it has highly• characteristic ridges. The arrow marks the small mouth entrance. Among 1000 soil samples investigated, this species occurred only in a single• sample from the Caribbean coast of Costa Rica, Central America; thus it is possibly a regional endemic; 11-13 - Sleighophrys pustulata (11, 12)• and Luporinophrys micelae (13) are rod-shaped, about 200 μm long Venezuelan flagships with highly characteristic epicortical scales (12, 13),• which are 5-12 μm high and thus easily recognizable also in the light microscope.