Characteristic Features: Sexual and asexual spores
Embryo Formation: None
remember that these are all Eukaryotes so they have these characteristics too:
•Up to 40 µm
•Paired chromosomes, in nuclear membrane
•80S ribosomes
•Organelles
•Polysaccharide cell walls
•Mitosis/Meiosis
Fungi are grouped into two morphological groups: molds (and fleshy fungi) and yeasts:
•Molds and fleshy fungi
–Multicellular
–Made of filamentous microscopic cells called hyphae
– In right environmental conditions, hyphae growth becomes visible (mycelium)
–Reproduce by spores (sexual and asexual)
•Yeasts
–Unicellular
–Non-filamentous cells
–Reproduce by budding (dividing asymmetrically) or fission (divide symmetrically)
List the four phyla of fungi described in this chapter.
•Zygomycota =conjugation fungi
–Saprophytic molds (bread mold)
•Ascomycota = sac fungi
–Includes molds and yeasts (like ones for brewing beer)
•Basiciomycota = club fungi
–Fleshy fungi (mushrooms!)
•“Deuteromycota” = fungi imperfecti
–Unknown sexual stages
–Include most pathogenic fungi
Identify two beneficial and two harmful effects of fungi.
Fungi are an important part of the environment for the major role they play in decomposing and recycling organic matter
Some beneficial effects of fungi are:
producing citric acid for foods and beverages
the yease Saccharomyces cerevisiae is used to make bread and wine; it is also genetically modified to produce a variety of proteins, including hep B vaccine
Trichoderma is used commercially to produce the enzyme cellulase, which is used to remove plant cell walls to produce a clear fruit juice
The anticancer drug taxol is produced by yew trees and the fungus Taxomyces
Fungi are also used as biological controls of pests
Some harmful effects are:
mold spoilage of fruits, grains, and veggies
The spreading chestnut tree and the American elm population have almost been wiped out because of fungus
Define mycosis.
Describe how they are defined (eg. subcutaneous, superficial…)
Mycosis is a fungal infection. Mycosis are generally chronic (long-lasting) infections bc fungi grow slowly
Mycoses are classified into 5 groups according to the degree of tissue involvment and mode of entry into the host:
systemic: fungal infections deep within the body. They are not restricted to any particular region of the body but can affect a number of tissues and organs. Inhalation of spores is the route of transmission; these infections typically begin in the lungs and then spread to other body tissues; not contagious
Two systemic mycoses: histoplasmosis and coccidioidomycosis
subcutaneous-fungal infections beneath the skin caused by saprophytic fungi that live in the soil and on vegetation. Infection occurs by direct implantation of spores or mycelial fragments into a puncture wound in the skin
Sporotrichosis is a subcutaneous infection acquired by gardeners and farmers
cutaneous-Fungi that infect only the epidermis, hair and nails are called dermatophytes, and their infections are called dermatomycoses or cutaneous mycoses. Dermatophytes secrete keratinase, and enzyme that degrades karatin. Infection is transmitted from human to human or from animal to human by direct contact with infected hairs and epidermal cells (as from barber shop clippers or shower room floors)
superficial-localized along hair shafts and in superficial (surface) epidermal cells. These infections are prevalent in tropical climates
opportunistic-generally harmless in its normal habitat but can become pathogenic in a host who is seriously debilitated or traumatized, who is under treatment with broad-spectrum antibiotics, whos immune system is suppressed by drugs or by an immune disorder, or who has a lung disease
Pneumocystis and Stachybotrys are opportunistic pathogens
Name and identify the fungal infections/diseases on the powerpoints.
(some are also in definition part)
Superficial mycoses:
Dermatomycoses
-commonly caused by dermatophytes (skin loving)
Also called "tinea" or "ringworm" infections
Tinea Versicolor
-White irregular spots on dark skinned individuals
-Reddish spots if fair skinned
-Caused by Malazzesia furfur
-“Spaghetti & Meatballs”appearance in Lactophenol Cotton Blue stain
Subcutaneous Mycoses:
Sporotrichosis
-Caused by Sporotrix schenckii
- Fungi introduced via splinters and rose thorns
-“Rosary bead” like nodules and lesions on extremities
Systemic Mycoses: worst kind you can get!
Histoplasmosis
• Caused by Histoplasma capsulatum, a dimorphic fungus (two shapes)
•Endemic in Ohio River Valley
•Pulmonary lesions and calcifications common in Histoplasmosis
• How is someone infected with H. capsulatum? The
fungus grows in soil and material contaminated with bat or bird droppings.Spores become airborne when contaminated soil is disturbed. Breathing the spores causes infection
Define lichen.
a combo of a green alga (or a cyanobacterium) and a fungus.
Placed in the Kingdom Fungi and are classified according to the fungal partner, most often an ascomycete
the two organisms exist in a mutualistic relationship, in which each partner benefits; if either are separated then the lichen no longer exists
List the defining characteristics of algae.
Algae are relatively simple eukaryotic, unicellular, filamentous, or multicellular photoautotrophs that lack the tissues (roots, stem, and leaves) of plants
Thallus: body of a multicellular alga;
thalli of the larger multicellular algae, commonly called seaweeds, consists of branched holdfasts (which anchor the alga to a rock), stemlike and often hollow stipes, and leaflike blades.
List the defining characteristics of protozoa.
•Eukaryotic
•Protist Kingdom
•Unicellular
•Absorptive; ingestive (food acquisition method)
•Most are motil and some form cysts
-Protozoans are chemoheterotrophs that found in soil, water, and some reside in animal hosts.
-Trophozoite stage - vegetative or feeding stage is frequently the cause of the pathology.
-Cyst stage – non-feeding and
resistant form that can withstand harsh environmental conditions. This is usually the infective stage.
Differentiate an intermediate host from a definitive host.
The mosquito is the definitive host because it harbors the sexually reproducing stage of Plasmodium. The host in which the parasite undergoes asexual reproduction (in this case, the human) is the intermediate host
book definition:
Definitive host: an organism that harbors the adult, sexually mature form of a parasite
Intermediate host: an organism that harbors the larval or asexual stage of a helminth or protozoan
List the distinguishing characteristics of parasitic helminths.
Animilia Kingdom
Chemoheterotrohpic
multicellular
eukaryotic
generally possess digestive, circulatory, nervous, excretory, and reproductive systems
may lack a digestive system (they can absorb nutrients from the host's food, body fluids, and tissues)
their nervous system is reduced
their means of locomotion is occasionally reduced or completely lacking
their reproductive system is often complex (can reproduce sexually or asexually)
List the characteristics of the two classes of parasitic helminths, and give an example of each.
Platyhelminthes (flatworms) and
Nematoda (roundworms)
Compare and contrast platyhelminthes and nematodes and diseases they cause.
Flatworms (platyhelminthes) are dorsoventrally flattened animals; parasitic flatworms may lack a digestive system.
Adult trematodes, or flukes, have an oral and ventral sucker with which they attach to host tissue.
A cestode, or tapeworm, consists of a scolex (head) and proglottids.
Humans serve as the definitive host for the beef tapeworm, and cattle are the intermediate host.
Humans serve as the definitive host and can be an intermediate host for the pork tapeworm.
Humans serve as the intermediate host for Echinococcus granulosus; the definitive hosts are dogs, wolves, and foxes.
Roundworms (nematodes) have a complete digestive system.
The nematodes that infect humans with their eggs are Enterobius vermicularis (pinworm) and Ascaris lumbricoides.
The nematodes that infect humans with their larvae are Necator americanus, Trichinella spiralis, and anisakine worms.
Define arthropod vector.
Jointed-legged animals, including ticks and insects, belong to the Phylum Arthropoda.
Arthropods that carry diseases are called vectors.
Elimination of vectorborne diseases is best done by the control or eradication of the vectors.
Differentiate between a tick and a mosquito, and name a disease transmitted by each
Ticks are classifed in arachnida
Mosquitoes are classified in Insecta
Fungi
a eukaryotic absorptive chemoheterotroph chemoheterotroph
mycology
the study of multicellular fungi and yeasts
Funal allergens
-“Sick Building Syndrome” is caused by a black mold growing on damp cellulose parts of buildings, Stachybotrys chartarum
-Considered as an EID, it causes Pulmonary Hemorrhagic Syndrome in infants.
Mycetismus
-Brought about by ingestion of hallucinogen producing and poisonous mushrooms
-Muscarin a hallucinogen is produced by Amanita muscaria
-Death cap is associated with a poisonous mushroom, Amanita phalloides
mycosis
any fungal infection
Epidemiology of Mycoses
•Fungi and their spores are found almost everywhere in the environment. You can’t avoid them.
•It is your resistance barriers that keeps you
safe from fungal infection.
•Mycoses are typically acquired via inhalation, trauma or ingestion
•Only very infrequently are they spread from
person to person.
•Still, epidemics of mycosis can and do occur,
but typically through mass exposure (like bird droppings in or near the ventilation system of a building).
•Since most mycoses are not contagious, they
are typically not reportable other than when there or epidemics or when they effect a specific population (such as AIDS patients).
systemic mycoses
fungal infections deep within the body
Systemic mycoses: Fungi are inhaled into the lungs and subsequently are transported to other internal organs, usually through the bloodstream.
subcutaneous mycoses
fungal infections beneath the skin
Subcutaneous mycoses: Fungus must be traumatically implanted (via wound) into the body.
cutaneous mycoses
infection of the epidermis, hair and nails
Cutaneous Mycoses: Fungi infects skin, mucus membranes, hair, and/or nails and secretes metabolites into the skin. Person is definitely aware of the infection. An example of this is Epidermophyton floccosum, one of the causes of athlete's foot.
superficial mycoses
localized along hair shafts and in superficial (surface) epidermal cells
Superficial Mycoses: Most patients are not even aware that they have condition. Fungi is only growing on dead skin, hair and nails. Fungus never secretes metabolites into the body.
Mycotoxicosis
-Brought about by eating food contaminated with or exposure to fungal toxins
-Aflatoxin produced by Aspergillus flavus is associated with liver diseases such as hepatoma
opportunistic pathogen
generally harmless in its normal habittat but can become pathogenic in a host who is seriously debilitated or traumatized
True fungal pathogens vs. opportunistic fungi
•There are only four species of fungi that are
considered true pathogens…
- Blastomyces dermatiditis
- Coccidioides immitis
- Histoplamsa capsulatum
- Paracoccidioides brasiliensis
… the rest are considered opportunistic.
What’s the difference?
•Pathogenic fungi have the ability to actively attack and invade tissues of healthy individuals. They have specific enzymes and proteins that help them survive and reproduce within the body.
•Opportunistic fungi do not cause disease in healthy individuals, but can cause disease in those with a weakened immune system.
algae
a photosynthetic eukaryote; may be unicellular, filamentous, or multicellular but lack the tissues found in plants
Most are photoautotrophs
•Includes:
–Brown Algae
–Red Algae
–Green Algae
–Diatoms
–Dinoflagellates
–Water molds
red tide
a bloom of planktonic dinoflagellates
protozoa
unicellular eukaryotic organisms; usually chemoheterotrophic
Can be distinuished by their morphology
Taxa of Protozoan:
•Archaezoa: lack mitochondria, move by flagella,
digestive tract symbionts
One pathogenic species that feed off the intestinal lining is Giardia intestinalis .
Infection results from eating food / drinking water which has been contaminated by the organism - usually from feces.
A large number generates inflammation, which causes nausea, stomach ache and diarrhea. Chronic infestation may result in malnourishment, blocking absorption of food across their intestinal wall.
Trichomonas vaginalis (no cyst stage) lives in the human vagina but its numbers are usually controlled by the acidic vaginal environment. If vaginal environment becomes more basic, thrive and potentially cause sterility.
•Amoebozoa: called amoeba because of how they move; move by psuedopods, free living
Eat and move by extending parts of their bodies to form pseudopods.
Can live in many places around human body, but mostly found in the intestine.
The majority of the intestinal amoebae live inside us without causing significant problems.
Entamoeba histolytica feeds on the lining of the gut.
Irritation created can lead to condition known as amoebic dysentery. Contracted by eating or drinking fecally contaminated food or water.
•Percolozoa: can transform between amoeba, flagellated and encysted stages
In the summer of 2007 several deaths occurred
from meningoencephalitis caused by the protist Naegleria fowleri a parasitic microorganism that feeds on brain tissue.
•Infection very rare, but nearly always fatal.
•Cases most often occur during the dry, hot summer months, when water is warm and at low levels.
•Enters body through the nose; invades CNS by penetrating the olfactory mucosa and nasal tissues.
•Early infections: necrosis (tissue death) and hemorrhaging in the olfactory bulbs.
•Amoeba then climbs along nerve fibers through the floor of the cranium, into the brain.
Where Is Naegleria Found?
•Worldwide distribution, typically found in warm fresh water, temperatures ranging from 77– 95 F.
How to Reduce Your Risk
•Infection usually follows water-related activities (swimming underwater, diving, or any water sport that results in water going up the nose).
•Infection can only result from exposure to the amoeba’s environment, not from person-to-person contact.
•Apicomplexa: non-motile, obligate intracellular
parasites
• Plasmodium spp.cause the disease malaria (one of the most death causing pathogenic species of fungi).
• Now mostly confined to the tropics.
• Spread by the bite of the Anopheles mosquito.
• In human body, malarial parasites mostly infect the red blood cells.
• Schizogony (ski-zog’-oh-knee). Multiple nuclear divisions make multinucleate cell. Then cell quickly divides into many, causing the host cell to burst, whereupon the parasites find the next cell to infect.
• Symptoms periodic fevers. Coincide with the time the red cells burst to release the parasites (they all tend to do this at once).
•Cliliophora: move by cilia; may be own phylum with dinoflagellates and apicomplexa (Alveolates)
• Move by beating thousands of hair-like structures called cilia.
• Cilia are also used by some species to secure
food.
• Only one species of pathogenic ciliate known to parasitize humans : Balantidium coli.
• Colonizes large intestine and causes diarrhea.
•Euglenozoa: asexual reproduction
•Move by flagella
•Photoautotrophs (these dont cause any pathogenic diseases)
•Chemoheterotrophs (these do)
–Trypanosoma: Undulating membrane, transmitted by vectors. African sleeping sickness is a parasitic disease is spread by the bite of the tsetse fly.
–Leishmania: Flagellated form in sand fly vector, ovoid form in vertebrate host.
helminths
a parasitic roundworm or flatworm
Animal parasites
- Helminths are the parasitic worms studied in Parasitology
-Can reproduce sexually (male and female) or as hermaphrodites
Broken up into two main phylums:
Phylum: Platyhelminthes (flatworms)
Trematodes
Cestodes
Phylum: Nematoda (roundworms)
Life cycle of Helminths:
•Monoecious (hermaphroditic)
–Male and female reproductive systems in one animal
•Dioecious
–Separate male and female
Whether they are monoecious or Diocious they start out as an Egg turns into larva(e) then metamorphasize into adult
Platyhelminths
flatworms
Trematodes
flukes
often have flat, leaf-shaped bodies with a ventral sucker and an oral sucker
•Trematodes are the blood flukes that use humans as the definitive host. Definitive hosts carry reproducing adults.
-Schistosomiasis is caused by:
Schistosoma mansoni
S. haematobium
S. japonicum
-Reproduces and lays eggs in humans (when humans eat crayfish), then come out thru our feces, which go into water where snails ingest them. they then use the snails where their asexual reproduction occurs.
Cestodes
tapeworms
•Bodies of Cestodes or tapeworms consist of scolex (head) for attachment and proglottids (flat body segments)
•Use humans as intermediate host (which means we just carry one of their life cycle stages). (unlike the trematodes that use us as the definitive host-which is the wolf for the tapeworm)
-Taenia solium – pork tapeworm
-Taenia saginata –beef tapeworm
-Tapeworms acquire nutrition by absorption through their cuticle.
Nematodes
roundworms
The hookworms
•Hookworms are the second most common nematode infecting humans (800 million worldwide)
Three main species:
-Ancylostoma duodenale
-Necator americanus
-Trichinella spiralis
-Infection is acquired by larval penetration of the host
-Adult worms attach to intestinal mucosa and
feed on blood of host causing anemia
One common nematodes: Trichinosis (we get these by eating undercooked pork)
Another nematodes where the egg is infective rather then the larvae: Enterobius vermicularis (pinworms)
To get them we must ingest both male and females thru us ingesting fecal matters
Arthropod
animals characterized by segmented bodies hard external skeletons, and jointed legs
"the disease carrier"
some arthropod vectors:
Human louse can carry Epidemic typhus and a relapsing fever
Rat fleas have caused the Murine typhus and the black plague
Deer fly have been known to carry Tuleremia (bacterial disease)
Kissing bugs can carry Chaga' disease (tropical disease)
vector
pathogenic microorganisms carried by arthropods
-Biological vectors (support replication of the pathogen)
-Mechanical vectors (simply move the pathogen..doesnt help the pathogen)
hyphae
a long filament of microscopic cells in fungi or actinomycetes
in right environmental conditions, hyphae growth becomes visible (mycelium)
lichen
a mutualistic relationship between a fungus and an alga or a cyanobacterium
•Alga produces and secretes carbohydrates; fungus provides holdfast.
•Classified by the fungal species.
Very rarely pathogenic; if they are pathogenic, usually its of the skin
dinoflagellate
Dinoflagellates are grouped in with the algae
•Cellulose in plasma membrane
•Unicellular
•Chlorophyll a and c, carotene, xanthins
•Store starch
•Some are symbionts in marine animals
•Neurotoxins cause paralytic shellfish poisoning
Dinoflagellates and health
-Dinoflagellates of Gymnodinium and Gonyaulax spp. are associated with Paralytic Shellfish Poisoning. Their algal bloom is popularly referred to as Red Tide.
definitive host
an organism that harbors the adult, sexually mature form a parasite
intermediate host
an organism that harbors the larval or asexual stage of a helminth or protozoan
scolex
the head of a tapeworm, containing suckers and possibly hooks
proglottids
a body segment of a tapeworm containing both male and female organs
Cyst
a sac with a distinct wall containing fluid or other material; also a protective capsule of some protozoa
trophozoite
the vegetative form of a protozoan
The Archeae you don't have to worry about too much, they are the ancient bacteria and never make people sick!
The Prokarya are the bacteria.
The bacteria are split into two main groups: Gram positive and Gram negative. The Gram positive are only split twice into Firmicutes and Actinobacteria.
The gram negatives have 8 total groups although 3 don't have any disease causing species because they are photosynthetic (like plants).
The largest group of disease causing Gram negatives is the Proteobacteria. The complete list of the other gram negative groups is in Ch10 lecture. YOU WILL NEED TO KNOW THE GROUPS.... not the names of the bacterial species.
The domain Eukarya (eukaryotes with nucleus and organelles) has four main groups called kingdoms.
The animals,
plants (no diseases!),
fungi and
protists (protozoans).
In Ch12 I cover disease causing members of each of these. An exampe of a test question might be:
Malassezia furfur causes a skin infection. What taxonomic group does this organism belong to?
The answer to the Malassezia furfur taxonomic group is Fungi.
Test Question:
Monecious helminths reproduce with:
D. eggs and sperm
Monecious means hermaphroditic-which means one animal has both male and female reproductive organs (reproductive organs use eggs and sperm)
besides all that, helminths are in the Kingdom Animalia..so the first three answers wouldn't make sense
Test Question:
Which one of the following does NOT belong with the others?
A. Candida
The first three are from the Parasitic Helminths catagory while Candida is a virus (confirm by reading the definitions I have up there for Trematodes and Nematodes)
Test Question:
If a larva of Echinococcus granulosus tapeworm is found in humans, humans are the ___
C. Intermediate host
Definitive hosts carry the adult, or sexually mature form of a parasite while the intermediate host carries the larval or asexual stage
The other two are irrelavant
Test Question:
Sporotrix is a fungus. Which is NOT true about this organism?
A. it is a systemic fungus
it is subcutaneous mycoses
Test Question:
A mycelium is
a. a mutualistic relationship between a fungus and a plant
b. a specialized reproductive structure of a fungus
c. a partition between the cells of a fungal hyphae
d. a mass of conneccted fungal hyphae
d. a mass of connected funal hyphae
a. a mutualistic relationship between a fungus and a plantis a Lichen
Test Question:
Which of the following pairs is mismatched?
A. Trichonella = superficial fungus
Trichonella is a nematode
Test Question: fill in the blank
Spores are used by fungi for
reproduction
Test Question: fill in the blank
give the scientific names for one of the two major groups of parasitic helmiths
nematodes or platyhelminths
Test Question: fill in the blank
A mycosis that occurs in a keratin rich tissue such as skin, nails or hairs is called a(n) ___ mycosis
cutaneous
Test Question: fill in the blank
Histoplasmosis is an example of a(n) ____ mycosis
systemic
Test Question: fill in the blank
Filamentous fungal cells are called
hyphae
Test Question:
Name one of the parasitic helminthes we studied. In what organisms are the eggs, larvae and adult found?
long answer
please refer back to the flashcards. this may be a good long answer question to know!
Test Question: some of these may go back to ch10, such as this one
Bacillus and Lactobacillus are not in the same order. This indicates that which one of the following is not sufficient to assign an organism to a taxon?
A.
Test Question:
Which of the following is not true about scientific nomenclature?
B.
Test Question:
The phylogenetic relationship in proteobacteria is based on
C.
Test Question:
You could identify an unknown bacterium by all of the following except
B.
Test Question:
Viruses cannot be classified in a kingdom because
A.
Test Question:
Which of the following is used to classify organisms into the Kingdom Fungi?
C.
Test Question:
All of the following are fungi EXCEPT:
C.
Test Question:
All of the following groups of algae produce substances that are toxic to humans EXCEPT
A.
Test Question:
Which of the following statements about yeasts are true?
(1) Yeasts are fungi.
(2) Yeasts reproduce asexually by budding.
(3) Yeasts are facultatively anaerobic.
(4) All yeasts are pathogenic.
(5) Allyeasts are unicellular.
E.
Test Question:
Into which group would you place a multicellular organism that has a mouth and lives inside the human liver?
C.
Test Question:
Fleas are the intermediate host for Dipylidium caninum tapeworm, and dogs are the definitive host. Which stage of the parasite could be found in the flea?