Download ď - Google Sites

FUNGI-LABS 13 AND 14
PROTOZOA LABS- 15 AND 16
PARASITIC WORMS LABS 17 AND 18
Survey of Eucaryotic Microbes
•
•
•
•
Fungi
Algae
Protozoa
Parasitic worms
2
Kingdom Fungi
• divided into 2 groups:
– macroscopic fungi (mushrooms, puffballs, gill fungi)
– microscopic fungi (molds, yeasts)
– Yeasts are unicellular fungi that do not grow as hyphae
• Fungi are aerobic (molds) or facultative anaerobes
(yeasts)
• Majority are unicellular or colonial; a few have
cellular specialization
3
Microscopic Fungi
• Exist in two morphologies:
– yeast – round ovoid shape, asexual reproduction
– hyphae – long filamentous fungi or molds
• Some exist in either form – dimorphic –
characteristic of some pathogenic molds
• At room temperature, it grows as a mold.
• At body temperature, it grows as a yeast.
4
5
6
Fungal Nutrition
• All are heterotrophic
• Majority are harmless saprobes living off dead
plants and animals
• Some are parasites, living on the tissues of other
organisms.
• mycoses – fungal infections
• Growth temperature 20o-40oC
• Extremely widespread distribution in many
habitats
7
Fungal Organization
• Most grow in loose associations or colonies
• Yeast – soft, uniform texture and appearance
• Filamentous fungi that grow in the form of
multicellular filaments, called hyphae.
• – mass of hyphae called mycelium; cottony, hairy,
or velvety texture
– hyphae may be divided by cross walls – septate
– vegetative hyphae – digest and absorb nutrients
– reproductive hyphae – produce spores for reproduction
8
9
Fungal Reproduction
• Primarily through spores formed on reproductive
hyphae
• Asexual reproduction – spores are formed
through budding or mitosis; conidia or
sporangiospores
10
Asexual reproduction in fungi by
producing spores
11
Sexual reproduction in fungi
• Involves the union of two compatible nuclei
not necessarily two gametes with a
subsequent meiotic division .
• All life cycle consist of ;
• Plasmogamy- cell fusion
• Karyogamy-nuclear fusion
• Meiosis
12
13
14
Roles of Fungi
• Adverse impact
– mycoses, allergies, toxin production
– destruction of crops and food storages
– Some common fungal infection are Athlete’s foot,
ringworm and yeast infections.
– Some fungi can also produce strong toxins
(mycotoxins) can lead to hallucinations, canceror
paralysis.
15
Beneficial impact
decomposers of dead plants and animals
– sources of antibiotics, alcohol, organic acids, vitamins
– used in making foods and in genetic studies
• Saccharomyces cerevisiae is a species of budding yeast.
• It is perhaps the most useful yeast owing to its use since
ancient times in baking and brewing.
• Schizosaccharomyces pombe has been proposed for the
early stages of alcoholic fermentation.
• Because it metabolizes malic acid, this yeast would be
useful in excessively acid musts, but commercial
applications have not yielded consistently favorable results.
16
Sabouraud Agar
• Allow the growth of yeasts for laboratory
purpose.
• This selective medium has glucose,
peptone, and a low pH.
17
Kingdom Protista
• Algae
• Protozoa
18
Algae
• Photosynthetic organisms
• Kelps, seaweeds, euglenids, green algae, diatoms,
dinoflagellates, brown algae, and red seaweeds
• Microscopic forms are unicellular, colonial,
filamentous.
• Macroscopic forms are colonial and multicellular.
• Contain chloroplasts with chlorophyll and other
pigments
• Cell wall
• May or may not have flagella
19
Algae
• Most are free-living in fresh and marine water –
plankton.
• Provide basis of food web in most aquatic habitats
• Produce large proportion of atmospheric O2
• Dinoflagellates can cause red tides and give off
toxins that cause food poisoning with neurological
symptoms.
• Diatoms/ sea jewel have silica walls
20
21
Protozoa
•
•
•
•
Vary in shape, lack a cell wall
Most are unicellular; colonies are rare
Most are harmless, free-living in a moist habitat
Some are animal parasites and can be spread by insect
vectors.
• All are heterotrophic.
• Feed by engulfing other microbes and organic matter
22
Protozoa
• Most have locomotor structures – flagella, cilia, or
pseudopods.
• Exist as trophozoite - motile feeding stage
• Many can enter into a dormant resting stage when
conditions are unfavorable for growth and feeding –
cyst.
• All reproduce asexually, mitosis or multiple fission;
many also reproduce sexually – conjugation.
23
24
25
26
27
Helminths
• 50 species parasitize humans.
• Acquired though ingestion of larvae or eggs in
food; from soil or water; some are carried by insect
vectors
• Dioecious - either male or female reproductive
organs
• Monoecious /hermaphrodites- contains both male
and female organs
28
Parasitic Helminths
• Multicellular animals, organs for reproduction,
digestion, movement, protection
• Parasitize host tissues
• Have mouthparts for attachment to or digestion of
host tissues
• Most have well-developed sex organs that produce
eggs and sperm.
• Fertilized eggs go through larval period in or out
of host body.
29
Major Groups of Parasitic Helminths
1. Phylum Platyhelminthes/ Flatworms – flat, no
definite body cavity; digestive tract a blind pouch; simple
excretory and nervous systems
• cestodes (tapeworms) are intestinal parasites
• Trematodes or flukes, are flattened , nonsegmented
worms with sucking mouthparts.
– no specialized circulatory and respiratory organs, which
restricts them to flattened shapes that allow oxygen and
nutrients to pass through their bodies by diffusion.
30
Roundworms (nematodes)
• Roundworms (nematodes)- round, a
complete digestive tract, a protective
surface cuticle, spines and hooks on mouth;
excretory and nervous systems poorly
developed
31
32
33
Clonorchis sinensis
• The Clonorchis sinensis is a human liver fluke in the
class Trematoda, Phylum Platyhelminthes.
• This parasite lives in the liver of humans, and is found
mainly in the common bile duct and gall bladder, feeding
on bile.
• Free floating egg -> snail -> infected fish -> human
(gut)
34
Enterobius vermicularis
• The pinworm (Enterobius), also known as
threadworm or seatworm, is a nematode
(roundworm)
• a common human intestinal parasite, especially in
children
• Infection usually occurs through the ingestion of
pinworm eggs, either through contaminated hands,
food, or less commonly, water.
• The chief symptom is itching in the anal area.
35
36
37
Helminth Classification and Identification
• Classify according to shape, size, organ
development, presence of hooks, suckers, or
other special structures, mode of reproduction,
hosts, and appearance of eggs and larvae
• Identify by microscopic detection of adult
worm, larvae, or eggs
38