Introduction to Microbiology

1. Microbiology
An
introduction
Presented by
D. Mona
Othman
Albureikan
Lectures
(16, 18, 19,20)

2. I. Mycology is the study of
fungi.
2. The number of serious fungal
infections is increasing.
3. Most fungi are decomposers,
and a few are parasites of plants
and animals.
4. Mycologists are using rRNA
sequencing to classify these
organisms.
Fungi

3. -Multicellular fungi are identified on the basis of physical
appearance, including colony characteristics and
reproductive spores.
Characteristics of Fungi
Vegetative Structures
- They are composed of the cells involved in catabolism
and growth.
Molds and Fleshy Fungi
- A fungal thallus consists of filaments of cells called
hyphae.
- A mass of hyphae is called a mycelium.

4. (a)Septate hyphae have cross-walls. or septa. dividing the hyphae
into cell-like units.
(b)Coenocytic hyphae lack septa.
(c)Hyphae grow by elongating at the tips.
(d) Each part of a hypha is capable of growth.
Characteristics of fungal hyphae.

5. - The portion of a hypha that obtains nutrients is called the
vegetative hypha.
- The portion concerned with reproduction is the reproductive or
aerial hypha.
Characteristics of fungal hyphae.

6. -Yeasts are unicellular fungi.
- Yeasts are nonfilamentous.
- To reproduce, fission yeasts divide symmetrically whereas budding
yeasts divide asymmetrically.
- To produce two new cells.
- During fission, yeasts divide evenly to produce two new cells.
Yeasts

7. -During budding, the parent cell
forms a bud on its outer surface.
- The bud elongates.
- The parent cell's nucleus divides,
and one nucleus migrates into the
bud.
- Cell wall material is then laid down
between the bud and parent cell.
- The bud eventually breaks away.
- One yeast cell can in time produce
up to 24 daughter cells by budding.
7. Buds that do not separate from the
mother cell form pseudohyphae.
Yeasts

8. Dimorphic Fungi
- Dimorphism meaning
two forms of growth.
- The moldlike forms
produce vegetative and
aerial hyphae.
- The yeastlike forms
reproduce by budding.
- Pathogenic dimorphic
fungi are yeastlike at 37°C
and moldlike at 25°C.

9. Life Cycle
- Filamentous fungi can reproduce sexually and asexually.
- Both sexual and asexual reproduction in fungi occurs by the
formation of spores.
- Fungi are usually identified by spore type.
- Spores are formed from aerial hyphae.
- Asexual spores are formed by the hyphae of one organism.
- Sexual spores result from the fusion of nuclei from two
opposite mating strains of the same species of fungus.
- Fungi produce sexual spores less frequently than asexual
spores.

10. Life Cycle

11. Life Cycle

12. - One type is a conidiospore, or
conidium
(plural : conidia), a unicellular or
multicellular spore that is not
enclosed in a sac
- Conidia are produced in a
chain at the end of a
conidiopbore. (Aspergillus).
- Conidia formed by the
fragmentation of a septate
hypha into single, slightly
thickened cells are called
arthroconidia.
The two types of asexual spores

13. -Another type of
conidium, blastoconidia,
consists of buds coming
off the parent cell
- Such spores are found
in some yeasts, such as
Candida albicalls.
- A chlamydoconidium is
a thick-walled spore
formed by rounding and
enlargement within a
hyphal segment.
The two types of asexual spores

19. - The other type of asexual
spore is a sporangiospore,
formed within a sporangium, or
sac
- The end of an aerial hypha
called a sporangiophore.
-The sporangium can contain
hundreds of sporangiospores.
- Such spores are produced by
Rhizopus.
The two types of asexual spores

20. 1- The Zygomycota have coenocytic hyphae and produce
sporangiospores (asexual spores) and zygospores (sexual
spores).
2- The Ascomycota have septate hyphae and produce
ascospores (sexual spores) and frequently conidiospores
(asexual spores).
3- Basidiomycota have septate hyphae and produce
basidiospores; some produce conidiospores.
4- Teleomorphic fungi produce sexual and asexual spores.
5- Anamorphic fungi produce asexual spores only.
Medically Important Phyla of Fungi

21. - Any fungal infection is called a mycosis.
- Systemic mycoses are fungal infections deep within the body that
affect many tissues and organs.
- Subcutaneous mycoses are fungal infections beneath the skin.
- Cutaneous mycoses (dermatomycoses) affect keratin-containing
tissues such as hair, nails, and skin.
- Superficial mycoses are localized on hair surface cells and
superficial skin cells.
- Opportunistic mycoses are caused by fungi that are not usually
pathogenic.
- Opportunistic mycoses can infect any tissues. ( usually systemic).
Fungal Diseases

22. - Yeast infection. or candidiasis, is most frequently
caused by Candida albicalls .
- Candidiasis frequently occurs in newborns, in people
with AIDS, and in people being treated with broad
spectrum antibiotics.
- Some fungi cause disease by producing toxins. These
toxins
Yeast infection

23. -Saccharomyces and Trichoderma are used in the
production of foods.
- Fungi are used for the biological control of pests.
- Mold spoilage of fruits and vegetables is more common
than bacterial spoilage of these products.
- Many fungi cause diseases in plants.
Economic Effects of Fungi

24. 1. A lichen is a combination of an alga (or a cynobacterium) and a fungus.
2. The alga photosynthesizes, providing carbohydrates for the lichen; the
fungus provides a holdfast.
3. Lichens colonize habitats are unsuitable for either the alga or the fungus
alone.
4. Lichens classified basing on morphology to crustose, foliose, and fruticose.
Lichens

25. 1. Algae are unicellular, filamentous, or multicellular (thallus) .
2. Most algae live in aquatic environments but some on soil or on rocks.
Algae
3. Algae are eukaryotic.
4. The thallus of multicellular algae
usually consists of a stipe, a holdfast,
and blades.
5. Algae reproduce asexually by cell
division and fragmentation.
6. Many algae reproduce sexually.
7. Algae are classified according to their
structures, rRNA sequences and
pigments.
Characteristics of Algae

26. Algae reproduction

27. Selected Phyla of Algae

28. 1. Brown algae (kelp) may be harvested
for algin.
2. Algin, a thickener used in many foods
(such as ice cream and cake
decorations.
3. Algin is also used in the production of
rubber tire.
4. Red algae grow deeper in the ocean
than other algae.
5. The agar used in microbiological
media is extracted from many red algae.
6. members of Red algae can produce a
lethal toxin.
Selected Phyla of Algae

29. 7. Green algae have cellulose and chlorophyll a and b and store starch, as
plants do.
8. Diatoms are unicellular and have pectin and silica cell walls; some produce a
neurotoxin.
9. Dinoflagellates (plankton )produce neurotoxines (called saxitoxins) that
cause paralytic shellfish poisoning (PSP) and ciguatera.
10. The Oomycotes are decomposers and pathogens.
Selected Phyla of Algae

30. Peridinium, a dinoflagellate

31. 1. Algae are the primary producers in aquatic food chains.
2. Planktonic algae produce most of the molecular oxygen in the Earth's
atmosphere (80%).
3. Petroleum is the fossil remains of planktonic algae and diatoms.
4. Unicellular algae are symbionts in such animals as Tridacna.
Roles of Algae in Nature

32. 1. Protozoa are unicellular,
eukaryotic.
2. Protozoa are found in
soil and water and as
normal microbiota in
animals.
3. Some protozoa are an
insect pathogen, is sold
commercially as a nontoxic
insecticide to kill
grasshoppers.
Protozoa

33. 1. The term protozoa means "first animal,"
2. The vegetative form is called a trophozoite.
3. A trophozoite feeds upon bacteria and small
particulate nutrients.
4. Asexual reproduction is by fission, budding, or
schizogony.
5. Schizogony is multiple fission
5. Sexual reproduction is by conjugation.
6. During ciliate conjugation, two haploid nuclei fuse
to produce a zygote (Diploid).
7. Encystment Under certain adverse conditions,
some protozoa produce a protective capsule called a
cyst.
Characteristics of Protozoa

34. 1. Some protozoa transport food across
the plasma membrane
3. Some protozoa may have complex
cells with a pellicle.
-Ciliates take in food by waving their
cilia toward cytostome.
- Amoebas engulf food by surrounding it
with pseudopods and phagocytizing it.
- In all protozoa, digestion takes place in
membrane-enclosed vacuoles.
- The waste may be eliminated through
the plasma membrane or through a
specialized anal pore.
Nutrition of Protozoa

35. 1. Archaezoa lack mitochondria and
have flagella; they include
Trichomonas vaginalis .
- It is found in the vagina and in the
male urinary tract.
- It is usually transmitted by sexual
intercourse but can also be
transmitted by toilet facilities or
towels.
2. Microspora lack mitochondria and
microtubules.
- It cause diarrhea in AIDS patients.
Medically Important Phyla of Protozoa

36. 3. Amoebozoa or amoeba; they include Entamoeba histolytica.
- It causes amoebic dysentery.
4. Apicomplexa are obligate intracellular parasites.
- It has apical organelles for penetrating host tissue.
-They include Plasmodium that caused malaria.
Medically Important Phyla of Protozoa

37. 5. Ciliophora move by means of
cilia.
- Balantidium coli is the human
parasitic ciliate which cause
dysentery.
6. Euglenozoa move by means of
flagella and lack sexual
reproduction.
-They include Trypanosoma which
causes African sleeping sickness.
- It studied with algae because they
can photosynthesize.
Medically Important Phyla of Protozoa

38. References
• Microbiology: An Introduction Plus
MasteringMicrobiology with eText - Access Card
Package (11th Edition) Hardcover – January 2, 2012
by Gerard J. Tortora, Berdell R. Funke, Christine L.
Case.
• Some pictures from different sits.