Eukaryotes Flashcards
Pathogen
A bacterial, viral, fungal, agent of disease.
They are pathogenic because they are often feeding on their hosts
Pathogens have a (+-) relationship with us and we have a (+/-) relationship with them
Positive relationship with us
Negative relationship with them
Often when people say we have parasites they are referring to
Any multicellular organism that can infect our bodies
Endosymbiosis theory
Eukaryotes are Thought to have evolved via endosymbiosis with prokaryotes, a theory known as endosymbiosies
Cell absorbs another cell, doesn’t destroy it, rather forms a relationship with them
Challenge with eukaryotic pathogens
We have few differences with eukaryotic pathogens
Fungi
100,000 known species
Almost none are infectious
Most are oppurtunisttic- cause disease and immincompromised or weakened individuals
Macroscopic fungi
See with eye includes mushroom, etc
Microscopic fungi
Need a microscope, includes yeasts and molds
Fungi reproduce both….
Sexually and asexually
Fungi release what into the environment
Spores into the environment that trigger immune reactions
These spores are present at low levels pretty much everywhere hence why mold grows on food if left out
We use fungi in what
Wine Beer Vitamins Antiobiotics Bread Pizza
Because fungi are eukaryotic we can use it to produce something like
Incilin
How do fungi work
Land on food
Begin to grow
Secrete digestive enzymes and absorb resulting molecules
Fungi are important in ecosystems because
Important role in recycling materials and releasing nutrients into the soil (composting)
Fungi can break down things such as
Feather, hair; oils, wood, rubber, dead plants and animals
Most commmon fungal pathogens
Candida albicans
Happens when sugar levels are elevated or more moisture is available (diaper rash, type 2 diabetes)
Candida albicans can also cause
Yeast infections in mouth and vagina
Thrush
Caused by Candida albicans
Growth usually kept “in check” by bacteria
Bacteria and the yeast compete in a location such as the mouth, bacteria usually wins which is why candida doesn’t often thrive
Pneumocystis pneumonia
A serious infection of the lungs caused by fungus pneumocystis jirovecci
An opportunistic fungal pathogen
20% of adults may carry this fungus asymptomaticakky, and the immune system removes the fungus
Ring worm and athletes foot
Caused by a variety of fungal genera, very common and easily transmitted
Infects the skin
How to treat tinea - ringworm or atheletee foot
Drugs like clotrimazole or micoanzole,
These medications work by altering cell wall permeability in fungi
Conjunctivitis
Pink eye
Commonly caused by e. Coli but can also be caused by fungi
Valley fever
Cofcidiomycosis
Fungal infection you get from breathing in fungal spores from the air in desert areas like Mexico, central and South America
Usually associated with older people or immunocompromised
Protozoa
65,000 species
Free living unicellular eukaryotes (nonfungal)
Few infectious species
Taxoplasma gondii
Opportunistic infection from food or cat feces
Most people with cats have it
How do Protozoa move around
Do not have a cell wall
Often move with cilia (short extension of cell) or flagella (long extension of cell)
Amoeboid
Help Protozoa move (fake feet)
Spore forming for Protozoa
Helps Protozoa move
Giardia lamblia
Attaches to wall of gut, feed off of ingested material passing by
Protozoa have 2 common life stages
Triphozoite: the stage in which independent Protozoa are moving and eating by themselves
Cysts: similar to bacterial endospores, a dormant stable form of protozoa less hardy
Giardia lamblia
Protozoa
Does form cysts
Travel easily in water and are carried by currents
Can infect entire villages via drinking water
Trichimonas vaginalis
Protozoa that does not form cysts, transmitted only sexually because with requires food and nutrients
Most common intestinal parasite
Giardia lamblia
Sometimes called hikers disease, travelers, diarrhea, beaver fever
Giardiasis symptoms
Diarrhea
Excessive flatulence
Vomiting
Treatment for giardiasis
Symptoms usually subside without treatment in 2-6 weeks
Metronidazole was the standard, resistance is growing, also has serious side effects
Even after treatment: intestinal scarring
Amebiasis (amebic dysentery)
Caused by entamoeba hystolytica
Malaria
Transmitted by vector (mosquito bites)
Caused by Protozoa of the genius plasmodium
3 life stages of malaria
Meozoite
Sporozoite
Gametocyte
How does malaria happen
- Sporozoite pass from mosquito to bloodstream
- Sporozoite travel to liver, reproduce, and mature into merozoites
- Merizoites enter bloodstream, replicate, bursting out of red blood cells and infect new cells
- Some merozoites become gametocytes, infecting New mosquitos where they form sporozoite
Symptoms of malaria begin
Between 10-16 days after infection (when merozoites begin to appear in blood)
Effort to eradicate malaria has focused on 3 approaches:
Mosquitos (nets, lasers, etc)
Drugs (prophylactic and treatment)
Vaccines (so far, low efficacy)
Drug treatments for milaria
Chemiprophylaxis is a common strategy Quinolone antibiotics (based on quinine) significantly reduced the risk of infection
Challenges or drug treatments for milaria
Need dif drugs for dif stages
Resistance is spreading
Drug development is expensive
What we tried to control mosquitos with malaria
DDT eradication campaign (1955-1969) but now populations of mosquitos are resistant
We are trying bed nets
We might try: altering mosquito populations
Most prevelant ameba in tropical areas
Enamoeba hystolytica
Most causes in the U.S are imported
Amebiasis transmission
Fecal/ oral route (including fomites)
Direct contact
Mechanism of amebiqsis
Invested cysts become trophozoites in the intestines
Feed on bacteria (not usually trying to hurry you)
Invasive disease may develop
Trophozoites release enzymes that kill epithelial cells and cause ulcers
Complications related to amebiasis
May enter bloodstream can cause abscesses in the liver lungs and brain
Treatment for amebiasis
Usually nitroumidazole derivatives because they are highly affective against the trophozoites
Can asymptomatic patients of amebiasis still infect others
Yes
Asymptomatic cases become symptomatic between 4-10% of cases
Naegleria Fowler I
Known as brain eating amoeba
Not technically a true amoeba but a shape shifting amoeba-flagellate
Amoeboflagellate characteristics
Free living bacteria eating microorganism that lives in warm fresh water (thermofilw) including lakes ponds hot springs
Forms a cyst at 10 degrees Celsius
How does naegleria Fowleri infect people
Travels up the nose from water where it destroys brain tissue
Helminths
Worms
Multicellular animals
Usually transmitted by microscopic eggs
Two main forms of helminths
Flatworms
Roundworms
Helminths reproduction
Sexually and asexually
Fertilized eggs released into environment (typically in feces)
Helminths eggs are vulnerable so
They produce thousands of eggs!
Most helminths cause what
Gastrointestinal infections
Eosinophilia
Blood work from helminths pathogens usually revelabs eosinophilia (help right multicellular infections)
Pinworms
Adult pinworms reside and lay eggs in large intestine
They lay eggs on the Anus of infected person
Kids scratch their anus and touch others
Hookworms
Eggs in feces, eggs hatch in soil and develop larvae
Larvae penetrate human skin
Larvae then migrate through tissues to reach intestines and nervous system/ brain
Hookworms and immunity
Have multiple mechanisms to seeeee the immune response against them through cytokines and regulatory cells
Tapeworms
Type of helminth pathogen
Flattened segmented bodies
Scolex
Head end of tapeworm
Has hooks that allow it to attach to intestine
Proglittids
Body segment of tapeworms
Taenia species
Type of tapeworm (pork and beef tapeworm)
Only 3 species cause human infections
Transmission of tapeworms
Ingestion of cysticerci in raw or undercooked meat
Treatment for tapeworms
Antihelminthic drugs
Anti inflammatory agents
Surgery right remove cysterci
Mechanism of tapeworms
In the small intestine the worms scolex and neck emerge from the cysticercus
Worm attaches to intestinal wall
tapeworm reaches maturity after 5-12 weeks
Begins to release eggs
Complications of tapeworms
Cysticercoris occurs wen humans invest the eggs instead of cysterceri
Eggs are hatching in intensives
Larvae burrow in intestine
Migrate into tissues
Impairs tissue function
Helminths therapy
An experimental type of immunotherapy
Deliberate infestation with a helminths or with the eggs or a helminth
