1. Assist. Prof. Dr. Betül AKCESME03
General Microbiology BIO306
Assist. Prof. Dr. Betül AKCESME

2. Microbial diversity
Microbial diversity can be seen in many ways besides phylogeny, including cell size and morphology (shape), physiology, motility, mechanism of cell division, pathogenicity, developmental biology, adaptations to environmental extremes…

3. MICROBIAL DIVERSITY The tree domains of life
Three phylogenetically distinct cellular lineages have been revealed.
Eukaryotes cells
Eukarya
Prokaryotic cells
Bacteria Archea
All prokaryotes are not phylogenetically closly related
Archaea are actually more closely related to eukarya than to bacteria

4. Metabolic Diversity All cell requires energy Organic Chemicals
Inorganic Chemicals
Light
Microorganisms have exploited every conceivable means of obtaining energy from the environment

5. Waste Products inorganic compounds
Chemotrophs are organisms that obtain energy from chemicals (by the oxidation of electron donors in their environments)
Organisms that use organic chemicals are called Chemoorganotrophs.
Aerobes use oxygen to obtain energy
Anaerobes obtain energy in the absence of oxygen
Organisms that use inorganic chemicals are called Chemolithotrophs.
This form of metabolism is called Chemolithotrophy.
Chemolithotrophy only occurs in prokaryotes.
Inorganic compounds H2, H2S (hydrogen sulfide), NH3 (ammonia), and Fe21 (ferrous iron) can be oxidized
Waste Products inorganic compounds
İnorganic compounds H2, H2S (hydrogen sulfide), NH3 (ammonia), and Fe21 (ferrous iron).

6. Microorganisms that use light called phototrophs
They have pigments that allows them to convert light energy into chemical energy.
Phototrophs do not require chemicals as a source of energy.
Oxygenic Phototrophs (produces oxygen)
Anoxygenic Phototrophs (not produce oxygen)

7. •All cells require carbon as a major nutrient Heterotrophs
Which require organic compounds as their carbon source
Feed directly on autotrophs or live off products produced by autotrophs
Auototrophs
Which use carbon dioxide(CO2) as their carbon source.
Sometimes referred to as primary producers
Chemolithotrophs and phototrophs
Chemoorganotrophs
Auototrophs
(Primary producers)
heterotrophs

8. Microorganisms are present everywhere on Earth that will support life.
Organisms that inhabit extreme environments are called extremophiles
Habitats include boiling hot springs, glaciers, extremely salty bodies of water, and high-pH environments

9. Microbial Diversity
Bacteria
Archaea
Eukaryo
Prokaryote
Eukaryote

10. Bacteria

11. 1) Bacteria Proteobacteria Major group of bacteria
All known disease-causing (pathogenic) prokaryotes are Bacteria.
They include a wide variety of pathogens
Escherichia
Salmonella
Vibrio
Helicobacter
Phototrophic and chemolithotrophic Proteobacteria.
(a) The phototrophic purple sulfur bacterium Chromatium (the large, redorange, rod-shaped cells in this photomicrograph of a natural microbial community). A cell is about 10 m wide. (b) The large chemolithotrophic sulfur-oxidizing bacterium Achromatium. A cell is about 20 m wide. Globules of elemental sulfur can be seen in the cells (arrows). Both of these organisms oxidize hydrogen sulfide (H2S).

12. Bacteria Gram-Positive
Gram-positive organisms are able to retain the crystal violet stain because of the high amount of peptidoglycan in the cell wall.
cytoplasmic lipid membrane
thick peptidoglycan layer
capsule polysaccharides (only in some species)
flagellum (only in some species)
if present, it contains two rings for support as opposed to four in Gram-negative bacteria because Gram-positive bacteria have only one membrane layer.

14. Gram Staining
It is based on the chemical and physical properties of their cell walls.
Primarily, it detects peptidoglycan, which is present in a thick layer in Gram positive bacteria.
A Gram positive results in a purple/blue color
Gram negative results in a pink/red color.

15. Bacteria Cyanobacteria
Phylogenetic relative of gram positive bacteria.
They are oxygenic phototrophs. (obtain their energy through photosynthesis)
First oxygenic phototrophs to evolve on Earth.
Cyanobacteria can be found in almost every terrestrial and aquatic habitat: in oceans, fresh water - even bare rock and soil
Cyanobacteria include unicellular and colonial species. Colonies may form filaments, sheets or even hollow balls.

16. Many Other Phyla of Bacteria
– Green sulfur bacteria and green nonsulfur bacteria are photosynthetic – Deinococcus is extremely resistant to radioactivity – Chlamydia are obligate intracelluar parasites
Deinococcus
radiodurans
Chloroflexus (green
nonsulfur bacteria).
Phototrophic green bacteria.

17. 2) Archaea
They have no cell nucleus or any other membrane-bound organelles within their cells.
They are prokaryotic in general structure and they do share many bacterial characteristics.
But evidence is accumulating that they are actually more closely related to Domain Eukarya than to bacteria.
archaea and eukaryotes share a number of ribosomal RNA sequences that are not found in bacteria,
protein synthesis and ribosomal subunit structures are similar.

18. 2 domain:
Euryarchaeota
Crenarchaeota

19. Archaea 1. Euryarchaeota
Euryarchaeota can be organized into four types
Methanogens procaryotes that produce methane, strict anearobic, can not tolerate very low oxygen.
Extreme halophiles prokaryotes that live at very high concentrations of salt (NaCl) for metabolism and reproduction. Require oxygen
Extreme (hyper) thermophiles prokaryotes that live at very high temperatures. Carbon source CO2
Thermoacidophiles grow in moderately high temperatures and low-pH environments

20. Halophiles around the world
Halophiles around the world. (a) An aerial view of a salt pond at San Francisco Bay, California. The archaea that thrive in this warm, highly saline habitat produce brilliant red, pink, and orange pigments.

21. Figure 2. 31 Extremely acidophilic Archaea
Figure 2.31 Extremely acidophilic Archaea. The organism Thermoplasma lacks a cell wall. The cell measures 1 m wide.
Figure 2.30 Extremely halophilic
Archaea. A vial of brine with precipitated
salt crystals contains cells of the extreme
halophile, Halobacterium. The organism
contains red and purple pigments that
absorb light and lead to ATP production.
Cells of Halobacterium can also live within
salt crystals themselves

22. Archaea 2. Crenarchaeota
Most abundant archaea in the marine environment.
All cultured Crenarchaea had been thermophilic or hyperthermophilic organisms, some of which have the ability to grow at up to 113 °C
These organisms are either chemolithotrophs or chemoorganotrophs and grow in hot environments such as hot springs and hydrothermal vents

23. Not all archaea are adapted to extremes, and many are widely distributed in more moderate environments such as soils, oceans, and even animal intestines.

24. For rRNA analysis no necessarily need for culture
Microbiologists believe that we have cultured only a small fraction of the Archaea and Bacteria
For rRNA analysis no necessarily need for culture
Isolate rRNA from natural sample (soil or water)
Bypass the culturing steps (bottleneck in microbial diversity studies)

25. Microbial Eukaryo
Eukaryotic microorganism are related by cell structure and phylogenetic history
Plant-Animal “most derived”
Structurally simple eukaryotes lacking mitochondiral and some other organalles.

26. 3) Eukaryo
Protist
Algae
Protozoa
Fungi
Slime modes

27. Eukaryo 1) Protist Diverse group of eukaryotic microorganism.
Mostly unicellular organism.
Simple cellular organisation distungiused the protists from other eukaryotes, such as fungi, animals and plants.

28. 1) Protist Algae Most are photosynthetic like plants
"simple" because their tissues are not organized into the many distinct organs found in land plants.
They contain chloroplast
Environment containing few minerals
Primary Producers! All true algae therefore have a nucleus enclosed within a membrane and plastids bound in one or more membranes. Can live in environment containing only a few minerals, water, CO2, light.

29. 1) Protist
Protozoa
Protozoa are a diverse group of unicellular eukaryotic organisms
Many of them are motile.
Protozoa commonly range from 10 to 52 micrometers, but can grow as large as 1 mm, and are seen easily by microscope
Has no cell wall like algea and fungi.
Example of protozoa
Flagella
Paramecium

30. 2) Fungi large group of eukaryotic organisms Cell wall
One major difference is that fungal cells have cell walls that contain chitin, unlike the cell walls of plants, which contain cellulose
Fungi perform an essential role in the decomposition of organic matter and have fundamental roles in nutrient cycling and exchange.

31. They are motile and lack cell walls. (similar to protazoa)
3) Slime molds
They are motile and lack cell walls. (similar to protazoa)
Differ from protozoa
Their phylogeny
Complex life cycle
Motile cells aggragate to form a multicellular structure called fruiting body.

32. As a summary Protists include algae and protozoa Fungi are decomposers
The algae are phototrophic
Protozoa NOT phototrophic
Fungi are decomposers
Algae and fungi have cell walls, whereas protozoa and slime molds do not
are organisms that break down dead or decaying organisms, and in doing so, carry out the natural process ofdecomposition.[1] Like herbivores and predators, decomposers are heterotrophic, meaning that they use organic substratesto get their energy, carbon and nutrients for growth and development.

33. Microbial Eukarya.
(a) Algae; dark-field photomicrograph of the colonial green alga Volvox. Each spherical cell contains several chloroplasts, the photosynthetic organelle of phototrophic eukaryotes.
(b) Fungi; interference-contrast photomicrograph of spores of a typical mold. Each spore can give rise to a new filamentous fungus.
(c) Protozoa; phase-contrast photomicrograph of the ciliated protozoan Paramecium. Cilia function like oars in a boat, conferring motility on the cell.
Microbial Eukarya. (a) Algae; dark-field photomicrograph of the colonial green alga Volvox. Each spherical cell contains several
chloroplasts, the photosynthetic organelle of phototrophic eukaryotes. (b) Fungi; interference-contrast photomicrograph of spores of a typical mold. Each spore can give rise to a new filamentous fungus. (c) Protozoa; phase-contrast photomicrograph of the ciliated protozoan Paramecium.
Cilia function like oars in a boat, conferring motility on the cell.

35. END of Second Chapter!