Lesson 1
Sunday, 6 February 2022
9:08 pm
The Early Years of Microbiology
Hippocrates (ca. 460 - ca. 377)- wondered whether there is a
link between environment and disease.
Thucydides (ca. 460 - ca. 404)- questioned why he and other
survivors of the plague could have intimate contact with
victims and not fall ill again?
What Does Life Really Look Like?
Antoni van Leeuwenhoek (1623-1723)
o Began making and using simple microscopes
o Often made a new microscope for each specimen
o Examined water and visualized tiny animals, fungi, algae,
o and single-celled protozoa: "animalcules"
o By end of 19th century, these organisms were called
microorganisms; now they are also called microbes
• (1674) Leuwenhoek reported the existence of protozoa
• The microbial world- Leeuwenhoek reported seeing a
scene very much like this, full of numerous fantastic,
cavorting creatures.
• The microorganisms that Leeuwenhoek described can be
grouped into six basic categories: bacteria, archaea,
fungi, protozoa, algae, and small multicellular animals.
o The only types of microbes not described by
Leeuwenhoek are viruses, which are too small to be
seen without an electron microscope.
Reproduction of Leeuwenhoek's microscope
• This simple device is little more than a magnifying glass with
screws for manipulating the specimen.
, o The lens, which is convex on both sides, is about the
size of a pinhead.
o The object to be viewed was mounted either directly on
the specimen holder or inside a small glass tube, which
was then mounted on the specimen holder.
o Can only magnify 270x
Carolus Linnaeus (1707-1778)
o A Swedish botanist developed a Taxonomic System
Taxonomic System- a system for naming plants and animals
and grouping similar organisms together.
o Linnaeus and other scientists of the period grouped all
organisms into either the animal kingdom or the plant
kingdom.
Bacteria, Archaea and Fungi
Monday, 7 February 2022
5:26 pm
How Can Microbes Be Classified?
Bacteria and Archaea
o Prokaryotic (lack nuclei)
o Much smaller than eukaryotes
o Found everywhere there is sufficient moisture; some have
been isolated from extreme environments
o Reproduce asexually
o Bacterial cell walls contain peptidoglycan; some lack cell
walls
o Archaeal cell walls are composed of polymers other than
peptidoglycan
• Bacteria live singly or in pairs, chains or clusters in almost
every habitat containing sufficient moisture
, • Archaea are often found in extreme environments, such as
the highly saline and arsenic-rich, acidic, and oxygen-
depleted places. (e.g. Hydrothermal vents)
o No archaea are known to cause disease
Fungi
o Eukaryotic (have membrane-bound nucleus)
o Obtain food from other organisms
o Possess cell walls
Microscopic fungi include:
• Molds - multicellular; grow as long filaments; reproduce by
sexual and asexual spores.
• which are cells that produce a new individual without
fusing with another cell
• Penicillum chrysogenum- is a mold that produce
penicillin. Has long filamentous hyphae that intertwine
to form its body. It reproduces by spores.
▪ Ex: cotton growth on cheese, bread, and jams are
molds.
• Yeasts - unicellular; reproduce asexually by budding (a
process in which a daughter cell grows off the mother cell);
some produce sexual spores.
• Saccharomyces cerevisiae- which causes bread to
rise and produces alcohol from sugar (Bread, Wine,
and Beer). has long filamentous hyphae that intertwine
to form its body. It reproduces by spores.
• Candida Albicans- is a yeast that causes most cases
of yeast in women. (Fungi and their significance in the
environment, in food production, and as agents of
human disease)
, Protozoa and Algae
Monday, 7 February 2022
6:35 pm
Protozoa
o Protozoa is a Greek word for "first animal"
o Single-celled eukaryotes
o Similar to animals in nutrient needs and cellular structure
o Live freely in water; some live in animal hosts
o Asexual (most) and sexual reproduction
o They are considered parasite. And can cause infection.
Most are capable of locomotion by:
Pseudopods - cell extensions that flow in direction of travel.
• Are cellular extension used for locomotion and feeding as
seen in Amoeba proteus.
Cilia - numerous short protrusions that propel organisms
through environment
• Are short, motile, hair-like extrusion, as seen in Euplotes
Flagella - extensions of a cell that are fewer, longer, and
more whip like than cilia.
• Are whip-like extensions that are less numerous and longer
than cilia, as seen in Peranema.
Plasmodium- are nonmotile in their mature forms.
Algae
o Unicellular or multicellular
o Photosynthetic (chloroplast)
o Simple reproductive structures
o Categorized on the basis of pigmentation and composition of
cell wall
o Scientists and manufacturers use many algae-derived
products. Pharmacological importance
Large algae- are commonly called seaweeds and kelps, are
common in the world ocean.
Sunday, 6 February 2022
9:08 pm
The Early Years of Microbiology
Hippocrates (ca. 460 - ca. 377)- wondered whether there is a
link between environment and disease.
Thucydides (ca. 460 - ca. 404)- questioned why he and other
survivors of the plague could have intimate contact with
victims and not fall ill again?
What Does Life Really Look Like?
Antoni van Leeuwenhoek (1623-1723)
o Began making and using simple microscopes
o Often made a new microscope for each specimen
o Examined water and visualized tiny animals, fungi, algae,
o and single-celled protozoa: "animalcules"
o By end of 19th century, these organisms were called
microorganisms; now they are also called microbes
• (1674) Leuwenhoek reported the existence of protozoa
• The microbial world- Leeuwenhoek reported seeing a
scene very much like this, full of numerous fantastic,
cavorting creatures.
• The microorganisms that Leeuwenhoek described can be
grouped into six basic categories: bacteria, archaea,
fungi, protozoa, algae, and small multicellular animals.
o The only types of microbes not described by
Leeuwenhoek are viruses, which are too small to be
seen without an electron microscope.
Reproduction of Leeuwenhoek's microscope
• This simple device is little more than a magnifying glass with
screws for manipulating the specimen.
, o The lens, which is convex on both sides, is about the
size of a pinhead.
o The object to be viewed was mounted either directly on
the specimen holder or inside a small glass tube, which
was then mounted on the specimen holder.
o Can only magnify 270x
Carolus Linnaeus (1707-1778)
o A Swedish botanist developed a Taxonomic System
Taxonomic System- a system for naming plants and animals
and grouping similar organisms together.
o Linnaeus and other scientists of the period grouped all
organisms into either the animal kingdom or the plant
kingdom.
Bacteria, Archaea and Fungi
Monday, 7 February 2022
5:26 pm
How Can Microbes Be Classified?
Bacteria and Archaea
o Prokaryotic (lack nuclei)
o Much smaller than eukaryotes
o Found everywhere there is sufficient moisture; some have
been isolated from extreme environments
o Reproduce asexually
o Bacterial cell walls contain peptidoglycan; some lack cell
walls
o Archaeal cell walls are composed of polymers other than
peptidoglycan
• Bacteria live singly or in pairs, chains or clusters in almost
every habitat containing sufficient moisture
, • Archaea are often found in extreme environments, such as
the highly saline and arsenic-rich, acidic, and oxygen-
depleted places. (e.g. Hydrothermal vents)
o No archaea are known to cause disease
Fungi
o Eukaryotic (have membrane-bound nucleus)
o Obtain food from other organisms
o Possess cell walls
Microscopic fungi include:
• Molds - multicellular; grow as long filaments; reproduce by
sexual and asexual spores.
• which are cells that produce a new individual without
fusing with another cell
• Penicillum chrysogenum- is a mold that produce
penicillin. Has long filamentous hyphae that intertwine
to form its body. It reproduces by spores.
▪ Ex: cotton growth on cheese, bread, and jams are
molds.
• Yeasts - unicellular; reproduce asexually by budding (a
process in which a daughter cell grows off the mother cell);
some produce sexual spores.
• Saccharomyces cerevisiae- which causes bread to
rise and produces alcohol from sugar (Bread, Wine,
and Beer). has long filamentous hyphae that intertwine
to form its body. It reproduces by spores.
• Candida Albicans- is a yeast that causes most cases
of yeast in women. (Fungi and their significance in the
environment, in food production, and as agents of
human disease)
, Protozoa and Algae
Monday, 7 February 2022
6:35 pm
Protozoa
o Protozoa is a Greek word for "first animal"
o Single-celled eukaryotes
o Similar to animals in nutrient needs and cellular structure
o Live freely in water; some live in animal hosts
o Asexual (most) and sexual reproduction
o They are considered parasite. And can cause infection.
Most are capable of locomotion by:
Pseudopods - cell extensions that flow in direction of travel.
• Are cellular extension used for locomotion and feeding as
seen in Amoeba proteus.
Cilia - numerous short protrusions that propel organisms
through environment
• Are short, motile, hair-like extrusion, as seen in Euplotes
Flagella - extensions of a cell that are fewer, longer, and
more whip like than cilia.
• Are whip-like extensions that are less numerous and longer
than cilia, as seen in Peranema.
Plasmodium- are nonmotile in their mature forms.
Algae
o Unicellular or multicellular
o Photosynthetic (chloroplast)
o Simple reproductive structures
o Categorized on the basis of pigmentation and composition of
cell wall
o Scientists and manufacturers use many algae-derived
products. Pharmacological importance
Large algae- are commonly called seaweeds and kelps, are
common in the world ocean.
