INRODUCTION Flashcards
DEFINE PROTOZOOLOGY
Study of protozoa (unicellular organisms) in which all physiological functions are carried out by the organelles of the cell
KINGDOM PROTISTA
-Diverse collection of eukaryotic organisms
-which lack tissue differentiation
-Single celled
-Move independently
-Many are free living, others are parasites
complex life cycles that take place in the cells, bloodstream and tissues of the host (invertebrate-ticks, mosquitoes or vertebrates-mammals, avian)
Parasitic protozoa
Most are zoonotic – low host specificity
KINGDOM PROTISTA
Differences between Prophyta and Protozoa
cell wall- rigid/thick
nuclear material- well defined with membrane
nutrition– holozoic saprozoic
reproduction- binary fission along longitudinal axis except ciliates
Protozoa
cell wall - non rigid/ thin
nuclear material - dispersed
nutrition- holophytic
reproduction - binary fission along transverse axis
Types of Nucleus
Vesicular
Compact
chromatin concentrated in a single mass (endosome or nucleolus)
Vesicular
chromatin evenly distributed (homogenous), present in ciliates
Compact
reproductive function
Micronucleus
Organelles in the cytoplasm
(powerhouse of the cell)
Mitochondria
vegetative function
Macronucleus
carries organs of locomotion (prolongations of the ectoplasm)
Cytoplasm
outer part (homogenous and hyaline appearance)
Ectoplasm
(regulates osmotic pressure & eliminates waste material)
contractile vacuole
(protein synthesis)
Ribosomes
(enzymes for digestion)
Lysosome
(collect dehydrated proteins)
Golgi bodies
Functions ectoplasm:
Movement
Food ingestion
Excretion
Respiration
Protection
Granular, pigmented
Contains food vacuoles (role in nutrition)
Endoplasm
Movement of Protozoa
To obtain food
For reacting to physical and chemical stimuli
protozoa Very marked movement
flagellates and ciliates
Modes of Movement
Cilia
Pseudopodia
Flagella
Gliding
ciliates, Balantidium, Trichomonas (fine, short, flagella like structures
Cilia
false feet (Entamoeba)
Pseudopodia-
Mastigophora species (whiplike filamentous structure from a basal granule in the ectoplasm) ex. Trypanosomes
Flagella
Toxoplasma, Sarcocystis, Eimeria (no locomotory organelle
Gliding-
Types of Nutrition
Holophytic
Holozoic
Saprozoic
Autotrophic
No veterinary importance, COH synthesized by chlorophyll (characteristics of plants)
Holophytic
pseudopodia or a cytostome are used to ingest food material from plants or animals and passed to a food vacuole (Pre-formed food utilized thru special organs)
Holozoic
uses micropyle (micropore) to ingest fluids/solids
Eimeria
– ingest tissues of host through a temporary opening in the body wall (pinocytosis)
Entamoeba, Balantidium
absorb nutrients by diffusion and directly used by the organism; stored food seen inside glycogen granules (absorption of dissolved organic matter)
Saprozoic
live entirely from inorganic compounds (proteins, COH & lipids are synthesized from them)
Autotropic-
parasitic protozoa nutrition
= either holozoic or saprozoic; none are autotrophic or holophytic
Ways of Excretion
Osmotic pressure
Diffusion
Precipitation
Involves the contractile vacuoles, ectoplasm, cytopyge and other structures.
(Most common)
takes free molecular oxygen in and expels carbon dioxide
Aerobic respiration
Sexual -involves the male and female gametes
a) Conjugation
b) Syngamy
survive under low oxygen tension since free oxygen is seldom available in the intestine of host
facultative or obligate anaerobes
Asexual- does not involve the male and female gametes
a) Binary fission
b) Multiple fission (schizogony)
c) External budding
d) Internal budding or endopolygeny
e) Sporogony
Ciliata
Exchange nuclear materials:
Conjugation
macronuclei degenerate while the micronuclei divide and pass nuclear materials into each other forming a
synkarion
2 gametes of different sexes fuse to form a zygote which divides by multiple fission to form sporozoites
Syngamy
nucleus divides forming the macronucleus which reproduce into new individuals
Synkarion
2 gametes of different sexes fuse to form a zygote which divides by multiple fission to form
sporozoites
(gamonts in pairs)
Syzygy
microgamete (male gamete) and macrogamete (female gamete)
are produced from microgametocytes and macrogametocytes
2 daughter cells from a parent cell
- Division along the longitudinal axis except for ciliates (transverse axis)
- Nucleus divides first then the cytoplasm (Trypanosoma)
Binary fission
Nucleus divides several times before cytoplasm does
Multiple fission (schizogony)
Nucleus divides several times before cytoplasm does
- dividing form is known
schizont
daughter forms are
merozoites (Coccidia, Plasmodium)
2 or many daughter forms produced from parent cell (ectopolygeny) which is unequal size of fragment of the nucleus and cytoplasm
- Budded forms are separated off and then grow to full size
External budding
which is unequal size of fragment of the nucleus and cytoplasm
ectopolygeny
New progenies are formed within the parent cell and then break off, destroying it (Toxoplasma and Sarcocystis)
Internal budding or endopolygeny
simplified from of endopolygeny (produces 2 daughter cells)
Endodyogeny
- follows syngamy, sporozoites are formed within the walls of the cyst (multiple fission)
Sporogony
General Effects of Protozoa Infection
Absorb nutrients e.g
Trypanosomes
Interfere with normal metabolism by food absorption e.g.
Giardia
Produce toxin e.g.
Sarcocystin by Sarcocystis
. Phylum Sarcomastigophora
- Subphylum Mastigophora – with 1 or more flagella
- Subphylum Sarcodina – with pseudopodia
Destroys tissue e.g.
Coccidia
Destroy blood cells and hemopoetic organs e.g.
Babesia
Nucleus is of one type, except in
heterokaryotic Foraminifera
Locomotory organs are either
pseudo- podia or flagella or both.
This phylum sarcomastigophora includes three sub- phyla —
Mastigophora, Opalinata and Sarcodina
produces spores, no locomotory organ
Phylum Apicomplexa
Reproduction asexually, but when sexually it is essentially by
syngamy
characteristics:
All species are parasitic in nature.
Anterior part of the body forms apical complex.
Microspores generally present at some stage.
They reproduce sexually by syngamy.
Examples are:
Phylum Apicomplexa
Monocystis, Gregarina, Plasmodium, Babesia sp. and Perkinsus sp.
is made up of polar rings, rhoptries, micronemes, conoid and subpellicular microtubules.
apical complex
produce spores with polar filament
. Phylum Microspora
with amoeboid germinal elements in multicellular spores; trophozoites are multicellular
Phylum Myxozoa
Phylum Ciliophora characteristics:
Most of the species are free living, quite a number are commensal, some truly parasitic and a large number are found as symphorionts on variety of hosts.
-Simple cilia or compound ciliary organelles are present in at least one stage of life cycle.
-Nuclei are of two types.
with cilia e.g. Paramecium
. Phylum Ciliophora
is present even when surface cilia is absent.
Subpellicular cilia
Blood and Tissue Flagellates
Leishmania sp. and Trypanosoma sp.
Phylum Ciliophora characteristics:
Presence of typical contractile vacuole.
Nutrition heterotrophic.
Asexual reproduction by transverse binary fission, budding and multiple fission also occur.
Sexual reproduction involves conjugation, autogamy and cytogamy.
bear one or more long, slender flagella (sing.,flagellum) for locomotion.
Flagellates
All forms absorb nutrients from their hosts through the cell membrane (no phagocytosis or cytostomal ingestion)
Flagellates
contains members which are parasitic - live in blood or fixed tissues of vertebrates at some time in their life cycle.
Order Trypanosomatida
The flagellum is also called an —
by those engaged in protozoology to accentuate its structural differences from the flagellum of bacteria.
undulipodium
multiply asexually by binary fission, and certain species from resistant cysts.
Flagellates
are very close together – the kinetosome is too small to be resolved – only the kinetoplast is seen
Kinetosome and kinetoplast
has all four forms
Trypanosoma cruzi
possesses only amastigote & promastigote forms
Leishmania spp.
Of the seven genera in the Family Trypanosomatidae, only 2 genera, Leishmania and Trypanosoma, are important parasites of humans.
Leishmania sp. and Trypanosoma sp.
has only epimastigote & trypomastigote
Trypanosoma brucei -
- flagella protozoan parasites that live in the blood, lymph and varous tissues of their vertebrate hosts
- parasites of all vertebrate classes
- majority are transmitted by blood- feeding invertebrates, although other transmission mechanism exist.
trypanosoma
structure that gives rise to the flagellum
kinetosome
dense area of mitochondrial DNA that gives rise to a mitochondrion - located just posterior to kinetosome
kinetoplasm
first reported human infection with the zoonotic parasite in southeast asia
trypanosoma evansi