protozoa Flashcards
- Single-celled eukaryotic microorganisms belonging to
kingdom Protista
protozoa
adapted to different host species
Parasitic protozoa
Out of 10,000 species of parasitic protozoa, man harbors
only about
70 species
- Protozoa exhibit wide range of size
(1- 150 µ111)
phylum
protozoa
subphylum
-sarcomastigophora
-sporozoa
-cnidospora
-ciliophora
superclass
mastigophora
opalinata
sarcodina
subclass
phytomastigophora
teleospora
myxosporidea
ciliatea
zoomastigophora
toxoplasmea
microsporidea
haplosporea
rhizopodea
piroplasmea
actinopodea
Mode of transmission
*Two major methods of transmission of protozoal
infection:
*ingestion of the infective stage
* an arthropod vector
*few are transmitted by sexual contact
The following groups of protozoa are
considered:
-Amoebae that move by
means of pseudopodia
- Protozoa that possess
one to several flagella
-Protozoa that move
by means of many cilia
on the cell surface
-. Protozoa that do not exhibit an obvious
mode of mobility but can glide
nonetheless.
(This same group uses sexual reproduction
during the life cycle.)
. Protozoa that do not exhibit an obvious
mode of mobility but can glide
nonetheless.
morphology of protozoa
unicellular;a single cell-like unit
multicellular;a number of cells, making up a complex individual
morphology of metazoa
a single cell performs all the function:reproduction,digestion,respiration, excretion
physiology of protozoa
each special cell performs a particular function.
physiology of metazoa
example of protozoa
ameba
example of metazoa
tapeworm
two portion of cytoplasm
endoplasm
ectoplasm
Outer homogeneous part that serves as
the organ for locomotion and for engulfment of food
by producing pseudopodia.
ectoplasm
The inner granular portion of cytoplasm
that contains nucleus. It shows number of structures:
the Golgi bodies, endoplasmic reticulum, food
vacuoles and contractile vacuoles.
endoplasm
usually single but may be double or
multiple; some species have as many as 100 nuclei in a
single cell.
nucleus
The nucleus contains one or more
nucleoli or a
central karyosome.
- The chromatin may be distributed along the
periphery
(peripheral chromatin) or as condensed mass around the
karyosome.
Extranuclear chromatin material is called
* (e.g. as found in Entamoeba histolytica cyst).
Chromatoid body
It is a deoxyribonucleic acid (DNA) containing
body, situated peripherally or centrally within the nucleus
and found in intestinal ameba,
* e.g. E. histolytica, E.coli.
Karyosome
3 types of karyosphere
-karyosphere with capsule
-karyosphere without capsule-
- inverted karyosphere
Nonnuclear DNA
present in addition to
nucleus.
Kinetoplast
it is seen in trypanosomes
Kinetoplast
*Flagellum originates near
kinetoplast
Point of origin of flagellum is
called as
basal body
These are fine, needle-like filaments, covering
the entire surface of the body and are found in
ciliates, e.g. Balantidium coli.
cilia
trophos:
nourishment
Active feeding and growing stage of the protozoa.
trophozoite
- trophozoite derives nutrition from the environment by
diffusion, pinocytosis,
and phagocytosis.
3 asexual reproduction
binary fission
multiple fission or schizogony
endodyogeny
It is a method of asexual
reproduction, by which a single parasite divides
either longitudinally or transversally into two or
more equal numbers of parasites.
binary fission
followed by division of
the cytoplasm.
Mitotic division of nucleus
division occurs along any plane
amebae
division is along longitudinal axis
flagellates
division occurs in the transverse plane
ciliates
Plasmodium exhibits schizogony,
in which nucleus undergoes
several successive divisions
within the schizont to produce
large number of merozoiles
- Multiple fission or schizogony:
Some protozoa
like Toxoplasma, multiply by
internal budding, resulting in the
formation of two daughter cells.
endodyogeny
2 sexual reproduction
conjugation
gametogony or syngamy
In ciliates, the
sexual process is _____
in which two organisms join
together and reciprocally
exchange nuclear material (e.g.
Balanlidium coli
Conjugation
In Sporozoa, male and female
gametocytes are produced,
which after fertilization form
the zygote, which gives rise to
numerous sporozoites by
sporogony (e.g. Plasmodium).
Gametogony or syngamy
Protozoa like intestinal flagellates and
ciliates require only one host, within which they
multiply asexually in the trophic stage and transfer
from one host to another by the cystic form.
- Single host
: In some protozoa like Plasmodium,
asexual method of reproduction occurs in one host
(man) and a sexual method of reproduction in another
host (mosquito).
- Second host
sarcos meaning
flesh or body
*It includes those parasites, which have no
permanent locomotory organs, but move
about with the aid of temporary
prolongations of the body called
pseudopodia
Phylum Sarcomastigophora
*Sarcodina
mastix meaning
whip or
flagellum
*It includes those protozoa which possess whiplike flagella (e.g. Trypanosoma and
Trichomonas).
Phylum Sarcomastigophora
*Masrigophora
Was formerly known as Sporozoa
Phylum Apicomplexa
serving as the organ of
attachment to host cells.
apical complex
Members of this group possess, at some stage in their life cycle, a structure called the apical complex serving as the organ of
attachment to host cells.
Phylum Apicomplexa
They are tissue parasites
Phylum Apicomplexa
They have a complex life cycle with alternating sexual and asexual generations
Phylum Apicomplexa
To this group, belongs the malarial parasites
Phylum Apicomplexa
- (Suborder: Hemosporina, Family: Plasmodiidae), Toxoplasma,
Sarcocystis,
lsospora, and Cryptosporidium ( Under the Suborder: Eimeriina),
Babesia (Under the Subclass: Piroplasma) and the unclassified Pneumocystis jirovecii.
malarial parasites
These protozoa are motile by means of cilia, which
cover their entire body surface.
Phylum Ciliophora
The only human parasite in this group is Balantidium
coli, which rarely causes dysentery.
Phylum Ciliophora
contains many minute intracellular
protozoan parasites, which frequently cause disease in
immunodeficient subjects.
Phylum Microspora
a is complex and is
subject to frequent revisions
zoological classification of protozoa
The classification described in
the chapter is an abridged version of the classification
proposed in 1980 by the Committee on Systematics and
Evolution of the Society of Protozoologists, as applied to
protozoa of medical importance
Phylum Microspora
