Eukaryotic Organisms

A Pictoral Guide ofSupportive Illustrations

to accompanySelect Topics on Eukaryotic Oranisms

By Noel Ways

Bacteria (Not Shown) -Agent of Disease

Reservoir

Vector

Favorable EnvironmentalConditions

induce Excystment

Adverse EnvironmentalConditions

induce Encystment

Cyst Trophozoite

ReproductionDuring

EnvironmentallyFavorable Conditions

Page 2

Schi

zogo

nyal

so k

now

n as

Mer

ogom

y(A

sexu

al)

Cells

1n

Mic

roga

met

ocye

s (1

n)“M

ale”

Mac

roga

met

ocye

s (1

n)“F

emal

e”

Spor

ozoi

te (1

n)

Zygo

te (2

n)in

Ooc

yst

Spor

ozoi

te (1

n) Gam

etog

ony Se

xual

Rep

rodu

ctio

n

Spor

ozoi

te (1

n)[ I

nfec

tive

]M

eroz

oite

s (1

n)[ I

nfec

tive

]

Trop

hozo

item

ay b

e M

eroz

ite

(pr

oduc

t of S

chiz

ogon

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ay b

e Sp

oroz

ite

(pr

oduc

t of x

xx)

Spor

ogam

y

Ase

xual

Rep

rodu

ctio

n

Meio

sis

Mito

sis

4 ce

lls (1

n)in

Ooc

yst

8 ce

lls (1

n)in

Ooc

yst

Gen

eral

ized

Life

Cyc

le C

once

pts a

nd T

erm

s

Page 3

Excystment inSmall Intestine

Disseminated infection results in organ

lesions /peritonitis and death

Encystment inLarge intestine

Note: bloodinvasion is

rare

Amoebiasis Life Cycle Entamoeba histolytica (invasive) Entamoeba dispar (non-invasive)

Cysts

Trophozoites(in Small Intestine)

FomitesFoodFecesWater

Fecal / OralRoute

LargeIntestine

Stomach

Ulcerations

BLOOD

Trophozoite Migration

Page 4

Cysts

Trophozoites

FomitesFoodFecesWater

Fecal / OralRoute

Giardia lamblia Life Cycle

Page 5

LargeIntestine

Stomach

Small Intestines

Excystment inSmall Intestine

Reservoir: Beavers stronglyimplicated. Also, many other wild

animals as well as domestic animals

Toxo

plas

ma

gond

ii Li

fe C

ycle

Cys

ts (n

) inj

este

d by

Cat

sex

cyst

and

par

asite

now

ente

rs in

test

inal

tract

whe

re th

eym

ultip

ly a

nd in

vade

hos

t.

Excr

eted

in F

eces

Zygo

te o

r Ooc

yst (

2n)

Spor

ozoi

tes (

n) a

re in

fect

ious

Mic

roga

met

ocyt

es (n

)

Mac

roga

met

ocyt

es (n

) Ooc

yst r

elea

sed

in fe

ces u

nder

gom

eios

is fo

llow

ed b

y m

itosi

s

Infe

cted

Und

erco

oked

Food

Feca

lC

onta

min

atio

n

Hum

an T

oxop

lasm

osis

Inge

stio

n of

Spo

rozo

ites b

y an

imal

s,pa

rticl

arly

rode

nts,

mai

ntai

nes o

rgan

ism

in n

atur

eas

cys

ts (n

) for

man

d ar

e re

peat

edly

rupt

ure,

rein

fect

, & in

jest

ed.

Som

e Pa

rasi

tes

unde

rgo

Met

amor

phos

is

Dig

estiv

e Tr

act o

f Cat

(Difi

nitiv

e H

ost)

Ooy

st n

owco

ntai

ns8

spor

ozoi

tes

Page 6

Occ

urs i

n En

viro

nmen

t

Pres

ent i

n w

ater

food

and

soil

Inte

rmen

diat

e H

osts

Imm

uno-

Com

prom

ised

Pers

onPa

ss T

hrou

ghPl

acen

taFe

tal D

efor

mat

y/ D

eath

Acu

teIn

fect

ion

Late

nt In

fect

ion

(Cys

ts)

in N

ervo

us S

yste

m(a

nd o

ther

org

ans)

EmbryonatedEggs hatch.

Miracidia developand seek out

species specific snail.

Miracidia penetratespecies specific

snail. Forms Redia

Cercaria seekout crayfish or crabs.

Cercaria penetrateand encyst forming Metacercaria within tissue.

Redia

Cercaria

Paragonimus westermani Life Cycle

Page 7

Man eats under-cooked crustaceans and metacecariae de-velop into flukes which migrate to lungs and other organs. In lungs, eggs produced are coughed up and swallowed, thereby leaving via feces.

References:Parasitology by Noble and NobleMicrobiology by Tortora

Redia asexually reporduce. Within rediae, cercaria are produced. Note tails. Cercaria will bore out andleave snail.

Gravid proglotids pass in fecesof man

Page 8

Eggs freed from gravid proglotids

Embryo liberated

Larvae travels via blood stream to skeletal muscle

Larvae encysts in skeletal muscle

UndercookedBeef

Head Evaginates and hooks into small intestine of man

Tapewormdevelops

Taeniarhynchus saginatus Life Cycle

Cows, Buffalo, etc.

2

9

3

4

5

1

10

11

6

7

12

13

14 8

12. Larvae are now reflexively swal-lowed.

13. Pass through stomach.

14. Enter small intestine and develop into adults.

Cycle now repeats: (start back at 1).

5. Fecally contaminated food with embryonated eggs ( ) injested

6. Embryonated eggs swallowed

7. Pass through stomach and enter small intestine

Fertilized Eggs

Fertilized EggEmbryonated Egg

Development

Larvae in Egg

8. Larvae ( ) hatch and bore through intestinal mucosa.

9. Enter hepatic portal system and migrate to liver, then right heart and then lungs.

10. Larvae enter alveoli. Patient may experience severe “ascaris pneumonitis at this time.

11. Tracheal Migration. Larvae migrate up respiratory tree to pharynx.

Ascaris lumbricoidesLife Cycle

References:CDC (http://www.dpd.cdc.gov/dpdx/html/Ascariasis.htm)An Illustrated Laboratory Text in Zoology by Boolootian and Heyneman c 1991

1. Sexual Reproduction results in copious egg ( ) production (~200,000 / day)

2. Fertilized eggs passed in feces

3. Embryo develops within egg case

4 Development continues, larvae

form.

Page 9

Summ

er(Year 1)

Larvae(Six Legged)

Fall --> Winter

(Year 1)

Nym

ph(Eight Legged)

Spring(Year 2)

Nym

ph

Summ

er(Year 2)

Nym

ph

Fall(Year 2)

Adults

Spring(Year 1)

Eggs

LIFE CY

CLE O

F THE D

EER TIC

K(V

ector for Borelia bergdorferi, agent of LYM

E DISEA

SE)

Uninfected

Infected

Blood Meal Results

in Infected Larvae ifrodents harbor bacterium

Blood Meal

Results in the innoculationof sm

all vertebrates

Small vertebrates,

particularly rodents,are "reservoir" forthe disease causingagent of Lym

e Disease.

Adults preferentiallyw

ill mate on W

hiteTail D

eer or shortyafter feeding upon them

Eggs are neverinfected

Should man inadvertently be fed upon by an infected

nymph or adult deer tick, the bacterium

of Lyme D

isease will be transm

itted

Nymphs Over-winter

EggsOver-winter

Page 10