Survey of MicroorganismsSurvey of Microorganisms

1. Virus2. Bacteria3. Cyanobacteria4. Algae5. Fungi6. protozoa

VIRUSVIRUS– Obligated intracellular parasite.– host specific:

bacteriophage animal virus plant virus

– according to its genetic material DNA virus RNA virus

– Shape: Most common shape is icosahedral , some are helical shape– Structure: Protein capsid and genetic material some animal virus have envelope with glycoprotein spikes– Life cycle: lytic infection lysogenic infection– Some animal virus are closely associated with

certain cancers

Comparison of naked and Comparison of naked and enveloped virusesenveloped viruses

The replication cycle of The replication cycle of a bacterial virusa bacterial virus(1)(1)

The replication cycle of The replication cycle of a bacterial virusa bacterial virus(2)(2)

The replication cycle of The replication cycle of a bacterial virusa bacterial virus(3)(3)

Consequences of infection by Consequences of infection by a temperate bacteriophagea temperate bacteriophage

Quantification of a bacterial Quantification of a bacterial virus by plaque assayvirus by plaque assay

Viral genomesViral genomes

PlusPlus/minus strand designation/minus strand designation

Formation of mRNA Formation of mRNA by different types of virusesby different types of viruses

Rolling circle replication of Rolling circle replication of bacteriophage lambdabacteriophage lambda

Shapes and relative sizes of Shapes and relative sizes of vertebrate virusesvertebrate viruses(1)(1)

Shapes and relative sizes of Shapes and relative sizes of vertebrate virusesvertebrate viruses(2)(2)

Possible effects of animals Possible effects of animals virus infection on cellsvirus infection on cells

Retrovirus structure and function(1)Retrovirus structure and function(1)

Replication process of Replication process of a retrovirusesa retroviruses(1)(1)

Replication process of Replication process of a retrovirusesa retroviruses(2)(2)

Retrovirus structure and function(2)Retrovirus structure and function(2)

Retrovirus Gene StructureRetrovirus Gene StructureGag : group antigensPol : Reverse TranscriptaseEnv : EnvelopeSrc : Code for Protein Kinase,

responsible for the malignant transformation

Onc: Oncogen is analogous to the Src gene - induce transformation

DNA tumor virusDNA tumor virus

1. Epstein Bar Virus – Burkitt’s Lymphoma

Nasopharyngeal carcinoma

2. Herpes Simplex type 2 – carcinoma of uterine cervix

3. Papilloma virus – uterine cervix

4. Hepatitis B – liver carcinoma

Taxonomy (1)Taxonomy (1)1. Species: Organism sharing a set of

biological traits and reproducing only their exact kind. (Species is the fundamental unit in taxonomy) a. strain: organisms within the species varying

in a given quality

b. types: organisms within the species varying immunologically.

2. Genus: closely related species

3. Family : closely related genera

Taxonomy (2)Taxonomy (2)

4. Order: closely related families 5. Class : closely related order 6. Phylum: related classes

Use nutritional patterns, as well as structure ones and biochemical properties, provide guidelines for classification of microorganisms. E.g.. Autotrophy, heterotopy, oxygen requirement etc.

Superkingdom Prokaryotes 

Kingdom Monera Bacteria

Cyanobacteria

Internal cell structure Internal cell structure (1)(1)

Superkingdom EukaryotesKingdom Protista

Branch protophyta

(Plant like protist)

algae

Branch protomycota (fungus like protists)

slime mold

Branch Protozoa

(animal like protists)

amoeba

Internal cell structure Internal cell structure (2)(2)

The electron micrographs of The electron micrographs of representativesrepresentatives

Kingdom Fungi

Kingdom Plantae

Kingdom Animalia

ArchaebacteriaArchaebacteria

It is a procaryotes, different from bacteria.

1. Cell MembraneForm lipid monolayer instead of lipid bilayer (in methanogens and thermophilic archaebacteria)

2. Cell WallArchaebacteria has no muramic acid and D-amino acids.Had pseudopeptidoglycan (use N-acetylglucosamine and N-acetyltalosaminuronic acid).Most of them are thermphile or halophilic, or methanogens. Anaerobic.

Summary of major differentiating features between Summary of major differentiating features between

eubacteria, archaebacteria and eucaryoteseubacteria, archaebacteria and eucaryotes

Characteristics Eubacteria Archaebacteria Eucaryotes

1. Membrane-

bound

nucleus absent absent present

2. Cell wall Muramic acid No Muramic acid No Muramic acid

3. Membrane lipids ester linked ether linked ester linked

4. Ribosome 70S 70S 80S

5. RNA polymerase One (4 sub) Several (8-12 sub) 3 (12-14 sub)

BACTERIABACTERIA

– Typical prokaryotes. – Three shapes: cocci, bacilli and spiral

– Can be autotroph or heterotroph– Autotroph: photoautotroph or

chemoautotroph

Heterotroph: parasite or saprophyte

– According to Gram stain: G+ or G-

– Type of reproduction: binary fission

– Some genetic material transfer:

– transformation, transduction and conjugation

Bacterial morphologies Bacterial morphologies (1)(1)

Bacterial morphologies Bacterial morphologies (2)(2)

Bacterial morphologies Bacterial morphologies (3)(3)

Bacterial morphologies Bacterial morphologies (4)(4)

The genetic map of the The genetic map of the F-plasmidF-plasmid

CyanobacteriaCyanobacteria– Blue green algae, in both fresh and marine water. – A typical procayrotic living organism– Autotroph, photosynthesis machinery is very similar to

higher plants. – No chloroplast, have chlorophyll and other pigments

such as phycocyanin, phycoerythrin, carotene etc.– Three forms: unicellular, colonial and filaments.– Some filament cyanobacteria have heterocyst that can

fix N2 to ammonia.

– e.g. Anacystis , Oscillatoria

FungiFungi

– Eucaryotic living organismsEucaryotic living organisms

– HeterotrophHeterotroph

(1) unicellular yeast (1) unicellular yeast

(2) muticellular molds(2) muticellular molds

(1) Yeast(1) Yeast

– Reproduction: Budding processes (asexual reproduction) forming

buds on the mother cell when mature, punch off to become new single yeast cells. sex spores (sexual reproduction), produce sex spores following the fusion of two separate cells.

– Many yeast convert carbohydrates to alcohol for alcoholic beverages (e.g. Saccharomyces cerevisiae)

– Some are used to raise bread (produce CO2 in the dough)

Multicellular fungiMulticellular fungi

– More complex than yeast, many of them become visible as “mildew” in damp weather. have hair like structure (mycelium)

– Sexual and asexual reproduction– Some mold are responsible for the flavor of

fine cheeses.– Major sources of antibiotics– e.g. Penicillium chrysogenum for penicillin

Slim Mold (lower fungi)Slim Mold (lower fungi)

– This is a lower fungi, in Protista and protomycota.

– It is similar to fungi, but distinct. – Heterotroph.– They live in cool, shady moist places in

nature - on decaying wood, dead leaves or other damp organic matter.

AlgaeAlgae– Eucaryotic living organisms– Autotroph:

Carry out a green plant type of photosynthesis resulting in the photolysis of water and the evolution of O2.

– Mainly aquatic in nature.– Some of the primitive ones are classified in protista;

complex multicellular types are placed in plant kingdom.

– Three forms: unicellular, filaments and colonial.– 7 classes on the basis of their cellular structure,

pigment composition. Only five will be discussed in here and differentiate them using food storage particles.

– e.g. euglena, spirogyra and cladophora.

AlgaeAlgae1. Euglenoids

eg. Euglenafood storage is a lipoid polysaccharide - paramylum

2. Green algaeeg. Chlamydomonasfood storage - starch

3. Golden Brown algaeeg. Diatomsfood storage – oil and leucosin (a polysaccharide)

have fucoxanthin, a brownish pigment

4. Brown Algae

Mainly marine water algae

food storage – laminarin, a polysaccharide and mannitol, a sugar alcohol

5. Fire Algae Dinoflagellate eg. Peridinium food storage – starch, fat, oils

ProtozoaProtozoa

– Unicellular, heterotroph– Animal like, move, they are either free

living or parasites.– A wide variety of shapes and sizes

some elongated, some are oval.– Sizes: from 5-10 um to 1-2 mm.– Sexual or asexual reproduction– e.g. amoebas, paramecium

ProtozoaProtozoaAsexually some exhibit sexual reproduction. Cyst, enables them to survive drought, heat and freezing.

Three Phyla:

1. Sarcomastigophora

subphyla Sarcodina Pseudopods eg. Amoeba

Mastigophora Zooflagellates eg. Heteronema

2. Ciliophora: most advanced and structurally complex of protozoa.

eg. Paramecium, Blepharisma, Stentor

3. Sporazoa

internal parasites eg. Plasmodium, the malarial parasite.