biological sciences 318- parasitology lab professor: carl lowenberger ([email protected]) office ssb...
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Biological Sciences 318- Parasitology Lab
Professor: Carl Lowenberger ([email protected])Office SSB 6121 tel 2-3985Laboratory SSB 6151 tel 2-4391
Lab Instructor Tammy McMullan ([email protected])Office BISC 9241 tel 2-3983
TA Sharra Farivar ([email protected])
Contact via email is best: please put BISC 318 in the subject line and indicate you are a student in the course!
Organization
Handout Materials:
Lab handout materials will be posted on Sunday/Monday before each lab. YOU should print it out and bring it to the lab.
Lab book! Keep your notes for review, for exam preparation, for the future, or just to get a good mark. Follow standard procedure for lab notes.
Time schedule ONLINE
LAB 1: Parasitic Protozoa
- Different stations with slides- Only 1 slide per person at a time.- Don´t break your slides!!!!!- All organisms of today´s lab will be studied under oil immersion.- Clean your slides with glass cleaner after using them!- Don´t give up! It is difficult to recognize and identify today´s samples.
Lab Evaluation
Grading: Lab exam 1 10%Lab exam 2 10%Participation: class and lab 5%Group Presentation 10% Total 35%
Group Presentation Each lab will contain 24 students. We will break you up into groups of 4. Each group will choose a parasitic disease not covered in the course. The group will present a 20-30 minute presentation on the problems associated with this parasite and disease and based on this course, other courses, and readings, propose what might be done differently from current strategies to reduce/eliminate problems and suffering from with this parasite. Presentations will be made in the lab sessions in the week of March 24 (subject to change).
Protozoan Parasites
What are Protozoa – Protista?
• Single-celled eukaryotes
• Some have >1 nucleus during all or part of their life cycles
• ~ 5 - 250 µm
Largely recognized after the development of microscopes
van Leeuwenhoek described all sorts of protozoa
• many form cysts (protection)
• invaded every ecological niche imaginable
• nearly every species of metazoan has a complement of protists living in it
Protozoa represent a unique type of evolution
Organelles are cellular elaborations performing the same functions as tissue and organs in “higher organisms“
• Locomotion and feeding: cilia, flagella, pseudopodia
• Osmoregulation: pulsatory vesicle, contractile vacuole
• Infraciliature: coordinating system of cilia
• Rhoptries: penetration of cells (Apicomplexa)
• Cell covered in 3-layered Plasma membrane
Giardia lamblia
Kingdom I Archetista (Archezoa)
Phylum Metamonada
Order Diplomonadida
Amitochondriate flagellated protozoan
Bilaterally symmetrical
Most primitive eukaryotes in existence
Organism and Disease Associations
Giardia lamblia, Giardia duodenalis, Giardia intestinalis
Giardiosis (back-packers diarrhea), beaver fever (but no fever)
Hosts and Host Range
Humans, dog, cats, beaver (reservoir), coyote, cattle
Geographic Distribution and Importance
Cosmopolitan
Most commonly reported human intestinal parasitic infection
Sporadic individual infections / epidemic form (drinking water)
Morphology
Trophozoite (motile, active feeding stage; vegetative stage)
is pear shaped, 10-20 µm long, 7-10 µm diameter
8 flagella
Binucleate - both nuclei are transcriptionally active
2 rigid median bodies
No mitochondria, peroxisomes, hydrogenosomes or other subcellular organelles for energy metabolism
Anterior region contains structure for attachment to epithelial cells
Structure is maintained with tubulin and giardins (calcium binding annexins)
Surface is covered with cysteine-rich molecules
Cysts (protective, infective stage)
ellipsoid
excyst in response to physiological / environmental stimuli
Following a series of stimuli: acid, pancreatic enzymes
Motile parasite divides into 2 binucleate parasites
BBN
AD
MB
A
PF
N
A
F
CW
Morphology
BBN
AD
MB
A
PF
N
A
F
CW
Slide: Giardia lamblia trophozoite:This parasite is generally tear-drop shaped with two visible nuclei. If you use the fine focus knob to focus in and out on the parasite you will be able to see the bi-lobed adhesive disc (smiley face).
Theory Practice
Slide: Giardia lamblia cyst: Giardia cysts are slightly smaller than trophozoites and have 4 visibly distinct nuclei. A median rod, known as an axostyles, is often visible down the centre of the organism.
direct
1. Cyst
2. Cyst ingested, swallowed
3. Excysts in duodenum, trophozoites attach to epithelial cells in small intestine
4. Division: Binary fission
5. Form cysts feces
Life cycle
Pathogenesis
Tissue: small intestine
Nausea, Diarrhea (> 7 days), weight loss, Steatorrhea, Malabsorption
Diagnosis
ELISA
Microscopic examination of stool
trophozoite
cysts
Trichomonas vaginalis
Kingdom II Euprotista
Phylum Parabasalia
Order Trichomonadida
Nearly all parasitic
Small flagellates
Only exist as trophozoites
Organism and Disease Associations
Trichomonas vaginalis
Trichomonad vaginitis or Trichomoniasis in women
Hosts and Host Range
Humans (men & women)
Geographic Distribution and Importance
Cosmopolitan
Prevalence of infection of 10 – 25% among women
Estimated 7.4 million new cases occur each year in women and men (CDC)
Men asymptomatic
Morphology
Basal bodyNucleus
Undulating membraneAxostyle
Terminal flagellum
Karyomastigont apparatus: • anterior tuft of flagella• axostyle• parabasal body (equivalent of GA)• costa• costal granules (hydrogenosomes energy metabolism)• nucleus
Oval and flagellated
1. Trophozoite
2. Binary fission
3. Direct transmission through sexual intercourse (no cyst stage)
Life cycle
Pathogenesis
Remain and multiply in vagina and cause inflammation of the epithelium. excessive production of mucus; pain. Can invade other organs such as kidney
Diagnosis
Microscopic examination vaginal swab, urethal swabs
Entamoeba histolytica
Entamoeba coli
Kingdom II Euprotista
Phylum Rhizopoda
Order Entamoebidae
Amoeba: organism that moves and feeds with pseudopodia.
Parasites (E. histolytica) or commensals (bulk; E. coli) of digestive system.
Organism and Disease Associations
Entamoeba histolytica
Amoebiasis, amoebic dysentery
Hosts and Host Range
Mainly humans
But: higher primates, dogs, cats and some rodents
Geographic Distribution and Importance
Cosmopolitan
50 million cases of invasive amoebiasis annually
50000 – 100000 deaths
3rd most common cause of parasitic death in the world
Morphology
GEE
N En
P
4N
En
Slide: Entamoeba histolytica trophozoite: Trophozoites are round with large lobular pseudopodia and a clock-face nucleus. The nuclear endosome is typically (but not always) centrally located. You may see erythrocytesin in the cytoplasm, indicating digestion of erythrocytes.
Theory Practice
Slide: Entamoeba histolytica cyst: Cysts are smaller than trophozoites. They contain 4 nuclei and chromatoid bars (tightly packed messenger RNA with rounded ends).
Morphology
Species 2: Entamoeba coli: Another species that occurs in the intestine of humans. It is a harmless commensal of the human large intestine, but looks similar to Entamoeba histolytica.
Therefore it is important to be able to distinguish between these two forms.
N En
8N
Slide: Entamoeba coli trophozoite: distinguished from E. histolytica by its coarser chromatin, eccentrically located endosome and the absence of erythrocytes in the cytoplasm.
Theory Practice
Slide: Entamoeba coli cyst: E. coli cysts contain 8 nuclei (compared to 4 nuclei seen in E. histolytica) and smaller chromatid bodies that are often filamentous.
1. Cysts and trophozoite in feces
2. Direct transmission; Ingestion of mature cysts
3. Excystation in small instestine
4. & 5 Tetranucleate amoeba divides into four amoebas which are carried to the large intestine.
Life cycle
Pathogenesis
Tissue: large intestine (colon, cecum)
Amoebic dysentery, erosion of mucosa and coating of the epithelium in the intestine, invasion of tissue causing flask-shaped ulcer
can reach the bloodstream
can finally result in peritonitis (bacteria reach abdominal cavity)
Diagnosis
Microscopic examination of stool
Balantidium coli
Kingdom II Euprotista
Phylum Ciliophora
Family Balantidiidae
Largest protozoan parasite of humans
Heterokaryotic (i.e. two kinds of nuclei)
Conjugation (temporary union of individuals and interchange of genetic material)
Only member of its phylum known to be pathogenic to humans
Organism and Disease Associations
Balantidium coli
Balantidiosis and balantidial dysentery
Hosts and Host Range
Humans, other primates, swine
Geographic Distribution and Importance
Cosmopolitan
Balantidiasis in humans is common in the Philippines, but it can be found anywhere in the world, especially among those that are in close contact with swine
Morphology
MiN
FV
C
MaN
M
N
CW
Slide: Balantidium coli trophozoite: trophozoites are oblong with a prominent kidney shaped macronucleus and a smaller micronucleus. B. coli is uniformly ciliated over its body but this is rarely visible on these slides.
Theory Practice
Slide: Balantidium coli cyst: cysts are round with a rounder and thicker macronucleus.
MiN
MaN
1. Cyst
2. Cyst ingested, swallowed
3. Excysts, Trophozoites
4. Division: Binary fission in small intestine. Trophozoite then colonize the large intestine, where they live in the lumen and feed on the intestinal flora. Some trophozoites invade the wall of the colon using proteolytic enzymes and multiply, and some of them return to the lumen.
5. Form cysts feces
Life cycle
Pathogenesis
In acute disease, explosive diarrhea may occur as often as every twenty minutes. Perforation of the colon may also occur in acute infections which can lead to life-threatening situations.
Diagnosis
Microscopic examination of stool
trophozoite
cysts
Trichomonas vaginalisGiardia lamblia
Trophozoite Cyst
Learning Objectives
1.Know general featrues of protozoans2.Order Diplomonadida- Visual ID Giardia lamblia – cyst + troph- Life cycles and roles of cyst + troph- Anatomy of troph + cyst- Transmission: from who, how, what stage, to who- Tissue where it is found- Pathology = symptoms and disease3.Order Trichomonadida- What makes them special? (2 things)- Visual ID Trichomonas vaginalis- Life cycle, anatomy and transmission4.Order Amoebida, Family Entamoebidae- How do they move- Visual ID Entamoeba histolytica and Entamoeba coli (trophs + cyst)- be able to visually differentiate between the two species- how do they differ in other ways- Life cycle, Transmission, Epidemiology, Pathology5.Phyllum Ciliophora, Family Balantidiidae- Visual ID Balantidium coli troph + cyst- What makes B.coli special- Life cycle, Pathology- Host, Tissue , Transmission
VocabularyProtozoanTrophozoiteCystGiardiosisFlagellaAxostyleAmoebaPseudopodiaPathologyTransmissionEpidemiologyErythrocyteErythrocytosineCiliaCommensalPathogenicEndosomeUlcer