Protists( 원생동물 ) - currently 100,000 species, 35,000 species found in fossils - lying in classification gap bwtn prokaryote and smallest animal and plants - all are unicellular, some exist as colonies - microscopic size ~ mm - practice all known modes of feeding -> phagocytosis -> absorb thru membrane -> parasites causing human and animal disease -> photosynthesis - movement by cilia, flagella, cytoplasmic extension(pseudopodia, 위족 ) - physiological variety -> fungus-like, plant-like, animal-like, -> combined characters of plants and animal, fungi and animal - asexual reproduction by mitosis is common, but sexual also - contain cellular compartment, subcellular organelles
Diatom( 규조류 ) Slime mold( 점균류 ) Volvox Amoeba proteus Chlamidomonas Trypanomonas
1. Protozoa - protozoa = proto(first) + zoa(animal) - lack cell wall, ingest food particle, move freely, no spore production - 40,000 species in aquatic environment, in moist soil, or as parasite - under ideal condition -> active feeding form (trophozoites, 영양체 ) - harsh condition -> transform into protective body (cysts, 피낭 ) => bioterrorism에이용 - environmental physiology : decomposer and recycle the nutrients - in aquatic food chain ->important as zooplankton( 동물플랑크톤 ) - feeding on micro algae, convert into nutrients -> marine invertebrate의먹이 - on land, nutrient-releasing functions in the digestive tracts of ruminant animal - classify four groups based upon motion type -> amoebas : move by pseudopod -> flagellates : by flagella -> ciliates : by cilia -> sporozoa : nonmotile in the adult form
Four major group of protozoa 아메바류 편모충류 섬모충류 포자충류
1) Amoeba - no definite form -> changing shape by pseudopodia for move and feed - Mastigamoeba : both flagella and pseudopodia - no photosynthesis -> heterotrophic nutrition - reproduction by mitosis, some by sexual reproduction - Foraminifera( 유공충류 ) : form hardened, shell-like casing(tests, 피각 ) -> 바다바닥의두꺼운침전층형성 ( 유전형성시기에생존 ) -> 유전개발의깊이표식기준 White cliffs ( 유공층잔해로형성 )
- Heliozoa( 태양충류 ) : freshwater amoeba, Radiolaria( 방산충류 ) : 해양침전물형성원인류 - pathogenic species are very rare, but -> Entamoeba histolyca : amoeiasis( 아메바증 ) 유발 -> 장궤양및통증유발 -> Acantamoeba : contact lense 사용자의각막염증유발 -> humidifier fever : allergic reaction caused by amoeba 2) Flagellates ( 편모충류 ) - long, hair-like flagella -> 9+2 arrangement of microtubule - most fundamental protists -> combination of good chemical talents and diversity
Euglena : freshwater microbe, nucleus, two flagellates - very flexible nutrient requirements - in sunlight : fully autotrophic by photosynthesis - in dark : lose photosynthetic pigments and become heterotrophic mode - return to light : resynthesizes photosynthetic pigments -> become autotroph - have eyespot sensing light ( 빛감지안점 ) long flagellum contractile vacuole chloroplast eyespot shielding a light-sensitive receptor ER nucleus Golgi body mitochondrion pellicle
Pathogenic flagellates - Trypanosoma brucei, Trypanosoma cruzi -> african and south american sleeping sickness Undulating membrane (fold of a pellicle, attached to part of flagellum) mitochondrion Golgi body free flagellum endoplasmic reticulum nucleus vacuole Trypanosoma brucei
Pathogenic flagellates - Giardia lamblia : 야영자도보자들의설사병, 야생동물에의한오염된물이원인 - Trichomonas vaginalis : trichomoniasis( 트리코모나스증 ) 의원인균 -> sexually transmitted disease over 2 million women per year - Leishmania tropica : 걸프전당시사막파리에의한미국병사들감염 Trichomonas vaginalis
3) Ciliates ( 섬모충류 ) - extremely diverse heterotrophic protozoa - size : 10μm ~ 3mm, 9+2 arranged hairlike cilia for movement - Paramecium ( 집신벌레 ) - two types of nuclei : macronuclei and one or more micronuclei -> macronuclei : cellular metabolism and growth -> micronuclei : cell division 의중심역할 food vacuole food residues being ejected gullet cilia trichocysts ( harpoons ) contractile vacuole emptied macronucleus micronucleus contractile vacuole filled
Reproduction of Paramecium by sexual conjugation
4) Sporozoa ( 포자충류 ) - at some stage in life cycle, develop a sporelike body - all are parasites, cause serious diseases in human and animal - Plamodium : cause malaria trasmitted by mosquito, over 300 million cases per year merozoite
Toxoplasmosis ( 톡소플라스마증 ) - blood disease acquired thru cat by Toxopalsma gondii Pneumocystis carnii - most serious illness in AIDS patients - over 50 % of all death associated with AIDS - no particular symptom in healthy person - during AIDS, immune system is suppressed -> parasites multiply quickly and take up all air spaces Toxopalsma gondii Cyclospora caryetanensis - 소화관질병유발, 나무딸기와관련성
2. Other Protists - some protists reside in the boundary of classification btwn plant, microbes, animal - algae is good example ->algae : seaweeds in Latin, meaning simple plant - two general types of algae -> unicellular : microbes vs multicellular : seaweed - unicellular algae : important relationship with society -> phytoplankton( 식물성플랑크톤 ) : 전형적해양단세포조류 -> generate most of molecular O 2 by photosynthesis -> produce over half of world s organic matter -> important role of food chain
1) Pyrrophyta ( 염색식물 division ) - so-called fire-algae( 화조류 ) because of bright red and orange pigments - photosynthesis, encased in rigid walls - all members are dinoflagellates( 쌍편모조류 ) -> first flagellum move forward, second whirls the cell on its axis ( dinos ) - some species are bioluminescent -> light up the sea in the night - cause red tides by burst reproduction under warm and plentiful nutrients -> produce poisonous toxin -> concentrate in sea shells -> 마비성패류중독 dinoflagellate
2) Chrysophyta ( 황갈조식물 division ) - golden-brown or yellow-green algae, include diatoms( 규조류 ) - diatoms are distinguished by delicate glasslike shells of silicon dioxide -> major component of the phytoplankton -> roles in oceanic food chain -> diatomaceous earth( 규조토 ), resulting from accumulation of diatom shells -> polishing, insulating, and filtering materials -> some are toxic to animals
3) Euglenophyta ( 유글레나식물 division ) - 800 species are known, Euglena is most notable - plantlike and animal-like 4) Chlorophyta ( 녹조식물, division) - Chlamydomonas is well-studies -> has complex life cycle => alteration of generation( 세대교번 ) -> characteristic in multicellular green algae or complex plant -> two forms of organisms : diploid and haploid -> mature Chlamydomonas is single haploid cell -> under normal environment, asexual reproduction -> sexual process under environmental stress producing fused diploid zygote
Life cycle of Chlamydomonas
5) Slime molds ( 점균류 ) - a collection of both plantlike and animal like microbes -> plantlike : enclosed in cell walls composed largely of cellulose -> animal like : have flagellated cells to move at some life cycle point plasmodium Dictyostelium discoideum
Fruiting bodies of slime molds
Life cycle of cellular slime molds