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Chapter 7. Protists
☞ 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
Chapter 7. Protists
Diatom(규조류)Diatom(규조류) Slime mold(점균류)Slime mold(점균류) VolvoxVolvox
Amoeba proteusAmoeba proteus ChlamidomonasChlamidomonas TrypanomonasTrypanomonas
Chapter 7. Protists
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) => bioterrorism에 이용
- environmental physiology : decomposer and recycle the nutrients
- in aquatic food chain ->important as zooplankton(동물플랑크톤)
- feeding on micro algae, convert into nutrients -> marine invertebrate의 먹이
- 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 protozoaFour major group of protozoaChapter 7. Protists
아메바류아메바류편모충류편모충류
섬모충류섬모충류 포자충류포자충류
Chapter 7. Protists
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)
-> 바다 바닥의 두꺼운 침전층 형성(유전형성시기에 생존)
-> 유전 개발의 깊이 표식 기준
White cliffs(유공층잔해로 형성)
White cliffs(유공층잔해로 형성)
- Heliozoa(태양충류) : freshwater amoeba, Radiolaria(방산충류) : 해양침전물 형성원인류
- pathogenic species are very rare, but
-> Entamoeba histolyca : amoeiasis(아메바증)유발 -> 장궤양 및 통증 유발
-> Acantamoeba : contact lense 사용자의 각막염증 유발
-> 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
Chapter 7. Protists
Chapter 7. Protists
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 (빛 감지 안점)
pelliclemitochondrionGolgi body
ER
nucleus
eyespot shielding a light-sensitive receptor
long flagellum
contractile vacuole chloroplast
Chapter 7. Protists
☞ Pathogenic flagellates
- Trypanosoma brucei, Trypanosoma cruzi
-> african and south american sleeping sickness
Undulating membrane (fold of a pellicle, attached to part of flagellum)
free flagellum
mitochondrion
Golgi body
vacuolenucleusendoplasmic reticulum
Trypanosoma bruceiTrypanosoma brucei
Chapter 7. Protists
☞ Pathogenic flagellates
- Giardia lamblia : 야영자 도보자들의 설사병, 야생동물에 의한 오염된 물이 원인
- Trichomonas vaginalis : trichomoniasis(트리코모나스증)의 원인균
-> sexually transmitted disease over 2 million women per year
- Leishmania tropica : 걸프전 당시 사막파리에 의한 미국병사들 감염
Trichomonas vaginalisTrichomonas vaginalis
Chapter 7. Protists
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 의 중심역할
food vacuole
food residues being ejected
gullet cilia
trichocysts (“harpoons”)
contractile vacuole filled
micronucleusmacronucleus
contractile vacuole emptied
Chapter 7. Protists
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
Chapter 7. Protists
☞ 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
☞ Cyclospora caryetanensis
- 소화관 질병 유발, 나무딸기와 관련성
Toxopalsma gondiiToxopalsma gondii
Chapter 7. Protists
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) : 전형적 해양 단세포조류
-> generate most of molecular O2 by photosynthesis
-> produce over half of world’s organic matter -> important role of food chain
Chapter 7. Protists
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 -> 마비성 패류중독
dinoflagellatedinoflagellate
Chapter 7. Protists
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
Chapter 7. Protists
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
Chapter 7. Protists
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
Dictyostelium discoideumDictyostelium discoideumplasmodiumplasmodium