3 Types Of Microorg

TYPES OF MICROORGANISMS

I. INTRODUCTION 

ACELLULAR ORGANISMS: VIRUSES 1.DNA containing viruses (e.g. warts, cold sores) 2. RNA containing viruses (e.g. polio, common cold)

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CELLULAR ORGANISMS 1. Kingdom : Procaryotae Bacteria Blue-Green algae (Cyanobacteria)

2. Kingdom: Protista Algae Fungi Protozoa 3. Kingdom: Plantae 4. Kingdom: Animalae

II. CELL STRUCTURE 

A. PROCARYOTES - Bacteria (Eubacteria, Archaeobacteria) - Blue-Green Algae (Cyanobacteria) - Size: 0.2-2.0 mm in diameter - Cell Division: Binary fission - simple division of a cell into 2 parts

Glycocalyx: 1. Slime Layer - not highly organized - not firmly attached to cell wall - Function: Enables the bacteria to glide or slide along solid surfaces.

2. Capsule - highly organized and firmly attached to cell wall - Function: for attachment and anti-phagocytosis Cell Wall - Primary function: Protection - Main Component: Peptidoglycan (murein) - Gram (+): thick layer of peptidoglycan (+) teichoic acid - Gram (-): thinner layer of peptidoglycan (+) outer membrane - Archaeobacteria: (-) peptidoglycan - Mycoplasma: no cell wall

APPENDAGES 

FLAGELLA - Threadlike protein appendages with a whip like motion that enable the bacteria to move (motility). - Arrangements: a. Monotrichous– single polar flagellum b. Amphitrichous– one flagellum at each end c. Lopotrichous– 2 or more flagella at one or both poles of the cell d. Peritrichous– flagella distributed over the entire cell

E. coli

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AXIAL FILAMENTS - found in Spirochetes - bundles of fibrils that arise at the ends of a cell and spiral around the cell.

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PILI OR FIMBRIAE - shorter, straighter and thinner than flagella - used as attachment - pili usually longer than fimbriae - functions: - enables bacteria to adhere or attach to surfaces - enables transfer of genetic material from one cell to another (sex pilus)

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PLASMA MEMBRANE -consists of proteins and phospholipids - controls substances that enter or leave the cell (selective permeability) - destroyed by alcohols and polymyxins

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CYTOPLASM - consists of water, enzymes, oxygen, waste products, essential nutrients, proteins, carbohydrates and lipids.

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CHROMOSOME (BACTERIAL NUCLEOID) -not surrounded by a nuclear membrane - does not have a definite shape - fewer proteins - serves as the control center of the bacterial cell -capable of duplicating itself, guiding cell division and directing cellular activities

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PLASMID - small circular, double stranded DNA - extra chromosomal genetic elements - carry genes for antibiotic resistance, tolerance to toxic metals, production of toxins and enzymes

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RIBOSOMES - site of protein synthesis - 70s ribosomes - smaller and less dense than eucaryotic ribosomes

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ENDOSPORES - resting structures formed by some bacteria for survival during adverse environmental conditions. - sporulation  process of endospore formation - germination  return of an endospore to its vegetative state

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INCLUSIONS - reserved deposits - metachromatic granules (volutin) Reserved for inorganic phosphate - polysaccharide granules glycogen and starch stores - sulfur granules  reserved for sulfur - lipid inclusions  lipid-storage material - carboxysomes  source of carbon during photosynthesis - gas vacoules  gas vesicles for bouyancy - magnetosomes  iron oxide

EUCARYOTES Protista- Algae, Fungi and Protozoa  Plantae  Animalae -cell size: 10-100 micrometer in diameter -cell division: Mitosis and Meiosis 

Cell wall - provide rigidity, shape and protection - simpler in structure - algae – cellulose fungi– chitin protozoa—no typical cell wall - no peptidoglycan layer

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Appendages 1. Flagella -organelles of locomotion - long, thin structures 2. Cilia - organelles of locomotion - shorter (hairlike), thinner and more numerous than flagella - coordinated rhythmic movement Plasma membrane 1. similar in function and basic structure with prokaryotes 2. structure -basic: proteins and phospholipids

CELL WALL

-others: - carbohydrates - serve as receptor sites - cell to cell recognition - attachment sites for bacteria - sterols (complex lipids) - resist lysis from increased osmotic pressure 3. Function: selective permeability - other functions: phagocytosis--- “cell eating” pinocytosis---”cell drinking”

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Cytoplasm - cellular material outside the nucleus and enclosed by the cell membrane. - composed of semi-fluid, gelatinous, nutrient matrix (cytosol) - contains insoluble storage granules and cytoplasmic organelles

MEMBRANE BOUND ORGANELLES 1.

NUCLEUS - unifies, controls and integrates the functions of the entire cell - surrounded by a nuclear membrane - NUCLEOLUS  condensed regions of chromosomes where ribosomal RNA is synthesized - usually spherical or oval

2. ENDOPLASMIC RETICULUM -

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Extensive network of flattened membranous sacs or tubules (cisterns) Continuous with the nuclear envelope Transports nutrients to the nucleus and also provides structural support for the cell. Rough ER -Ribosomes attached to outer surface - Function: protein synthesis Smooth ER -

no ribosomes attached

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Function: lipid synthesis

3. RIBOSOME - 80s - Produced in nucleolus ----free and membrane bound 4. GOLGI COMPLEX - flattened membranous vesicles - synthesis of secretory products for storage within the cell or export outside the cell (exocytosis or secretion)

5. MITOCHONDRIA - “power plant” of the cell - ATP formation by cellular respiration 6. LYSOSOMES - formed from GOLGI complex - store powerful digestive enzymes

7. CHLOROPLAST - found in algae and green plants - contains chlorophyll and the enzymes required for photosynthesis 8. MICROTUBULES - long, hollow tubes - consists of tubulin - provides support and shape - assists in transporting substances through the cell

PROCARYOTES

EUCARYOTES

Organisms

Bacteria

Algae, Fungi, Protozoa Animals, Plants

Size of cell

0.2-2.0 micrometer

10-100 micrometer

Cell Division/Rep.

Binary Fission

Mitosis/Meiosis

Cell Wall

Usually present and chemical complex

+/- (when present chem. Simple)

Glycocalyx

Present

Absent

absent absent

Present-serve as receptor Present—serve as receptor

No nuclear membrane or nucleoli

True nucleus with nuclear membrane and nucleoli

Ribosomes

Smaller size (70s)

Larger size (80s)

Membraneenclosed organelles

Absent

present

Cytoskeletons

Absent

Present

Flagella

Simple structure

Complex structure

Plasma Membrane CHO Nucleus

Sterols

PROCARYOTES  

Bacteria: Archaeobacteria & Eubacteria Basis for Classification: 1. Cell Morphology a. Spherical or round (cocci) b. rod-shaped (bacilli) c. curved and spiral-shaped (spirilium) d. Pleiomorphic 2. Cell arrangement a. in pairs: diplob. in chains: strepc. in clusters: staph-

3. Staining characteristics - gram (+) vs Gram (-) - AFB (Acid-Fast bacilli) 4. Motility 5. Colony morphology 6. Atmospheric Requirements - aerobes vs anaerobes 7. Nutritional requirements 8. Biochemical and metabolic activities 9. Pathogenecity 10. Amino acid sequencing 11. Genetic composition

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Classification 1. Archaeobacteria (Ex. Halobacterium) - contain cell walls but no peptidoglycan - closely related to eucaryotes - “extremophiles” 2. Eubacteria (“True” bacteria) A. Gliding Bacteria (Photosynthetic bacteria) -flexible cells, motility conferred by gliding - non-pathogenic bacteria (for humans) - ex. Cyanobacteria B. Spirochetes - flexible cells, motility conferred by endoflagella - ex. Treponema, Borrelia, Leptospira

C. Rigid Bacteria - rigid cells immotile or motility conferred by flagella 1. Mycelia (Actinomycetes) - branching filamentous growth which have external asexual spores (conidia) - similar to fungi -ex. Mycobacterium, Actinomycetes, Nocardia, Streptomyces 2. Simple Unicellular a. Obligate intracellular Parasite -depend on the host for energy rich compound and co-enzymes - ex. Rickettsiae (rickettsia, Coxiella) Chlamydiae (Chlamydia)

b. Free living Form - majority of pathogenic bacteria - General rule: All Cocci are gram (+) except: -- Neisseria, Branhamella, Veilonella All Bacilli are gram (-) except: --- Corynebacterium, Erysipelothrix, Mycobacterium, Clostridia, Listeria D. Lack Cell Wall (mycoplasma) - pleiomorphic

GRAM POSITIVE COCCI STAPH

RODS

STREP NON SPORE SPORE FORMER - Corynebacterium - Erysipelothrix - Listeria Obligate Obligate Aerobes Anaerobes (Bacillus)

(Clostridia)

GRAM NEGATIVE COCCI

RODS

Neisseria

Non Enteric Spiral Spirilium

Straight Pastuerella Brucella Yersinia Franciscella Hemophilus Bordetella Legionella

Enteric Facultative Anaerobes

Obligate Anaerobes

Escherichia Bacteriodes Salmonella Shigella Klebsiella Proteus Vibrio

Fusobacterium

Obligate Aerobe Pseudomonas

EUCARYOTES- ALGAE, FUNGI, PROTOZOA

EUCARYOTES 

PROTISTA--- ALGAE, FUNGI, PROTOZOA A. ALGAE - tiny, unicellular, microscopic microbes ( diatoms,dinoflagellates, desmids) - large, multicellular, plant like seaweeds (kelp) - energy production: photosynthesis (have chlorophyll) - cell wall: cellulose - basis for classification: PIGMENTS (green, brown or red algae) - Phycotoxins  substances poisonous to humans, fish and other animals  shellfish poisoning (RED TIDE/ paralytic shellfish poisonimg)

B. FUNGI - main source of food: decaying matter - have no chlorophyll - cell wall: chitin - cell membrane: ergosterol - forms: unicellular (yeasts), filaments (hyphae), mass (mycelia) - reproduce by  budding, hyphae extension, formation of spores -

Classification Of True Fungi Basis: mode of reproduction and type of mycelia, spore and gamete produced 1. Oomycetes– aseptate hyphae ex. Potato blight mold 2. Zygomycetes– usually aseptate hyphae ex. Bread mold (rhizopus) 3. Basidiomycetes (mushrooms)- septate hyphae 4. Ascomycetes– septate hyphae ex. Antibiotic-producing fungi

5. Deuteromycetes (Fungi Imperfect) - septate hyphae -most human pathogenic molds and yeasts a. Superficial and cutaneous mycoses dermatophytes: tinea, candida b. Subcutaneous and systemic mycoses Coccidioidomycoses, Blastomycoses, Histoplasmosis, Cryptococcus

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Clockwise from top left: Amanita muscaria, a basidiomycete; Sarcoscypha coccinea, an ascomycete; black bread mold, a zygomycete; a chytrid; a Penicillium conidiophore.

C. PROTOZOA - usually single-celled animal - no chlorophyll -ingest whole algae, yeasts, bacteria and other small - Classification – based on method of locomotion Class 1. Ciliophora

Movement cilia

2. Sarcodina

pseudopodia

3. Mastigophora

flagella

4. Sporozoa

non-motile

protozoas

Examples Balntidium coli Paramecium Entamoeba sp. Naegleria Giardia, Trichomonas Trypanosoma Plasmodium Toxoplasma Cryptosporidium

Ciliophora: Paramecium

Sarcodina: amoeba

Mastigophora: Gardia Lamblia

Malarial sporozoa

ACELLULAR ORGANISMS: VIRUSES 

Specific Properties 1. Possess either DNA or RNA (never both) 2. Replication is directed by the viral nuclei acid within a host cell. 3. Do not divide by Binary fission or mitosis 4. Lack the genes and enzymes necessary for energy production. 5. Depend on the ribosomes, enzymes and nutrients of the infected (host) cells for protein production.

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Lytic Cycle 1. Attachment --viruses attach to host cell with the correct receptor. 2. Penetration -- viral nucleic acid enters the cell 3. Biosynthesis -- genetic info contained in viral nucleic acid directs production of viral proteins and nucleic acids. 4. Assembly or Maturation -- viral proteins and nucleic acids are assembled into complete viral particles (virions) 5. Release– newly formed viruses/virions are released either by lysis or budding. -- most host cells are destroyed.

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Basis for Classification 1. Type of genetic material (DNA or RNA) 2. Shape of capsid (polyhedral, helical, complex) 3. Number of capsomeres 4. Size of capsid 5.presence or absence of an envelope 6. Host that it infects 7. Type of disease produced 8. Target cell 9. Immunological properties Classification DNA Viruses- Herpes, Hepadna, Adeno, Papova, Parvo, Pox RNA Viruses- Toga, Corona, Retro, Picorna, Calici, Reo, Orthomyxo, Paramyxo, Rhabdo, Bunya, Arena, Filo, Flavi

HIV VIRUS

Influenza virus

Quiz time

1. Acellular organism bacteria fungi virus 2. Ability to change form or shape pathogenic pleiomorphic aerobic

3. Source of food: decaying matter bacteria fungi virus 4. Algae poison mycotoxin phycotoxin endotoxin

5. Gram (-) cocci staphylococcus neisseria mycobacterium

PHYSIOLOGY OF THE ORGANISM

PHYSIOLOGY OF MICROORGANISM I. NUTRITIONAL REQUIREMENTS  Source of Energy

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--Phototrophs---light --Chemotrophs– inorganic or organic compounds Source of Carbon -- Autotrophs---CO2 -- Litotrophs—inorganic compound except CO2 -- Heterotrophs (Organotrophs) ---Organic compounds Energy Source and Carbon Source --Photoautotrophs---Light + CO2 ---ex. Plants, algae, cyanobacteria, purple and green sulfur bacteria --Photoheterotrophs (Photoorganotrophs) --- Light + organic compounds—ex. Green and purple non-sulfur bacteria

--Chemoautotrophs– Chemical + CO2 ex. Nitrifying, hydrogen, iron and sulfur bacteria --Chemolitotrophs--- Chemical + inorganic compound except CO2 -- Chemoheterotrophs– Chemical + organic compound ex. All animals, protozoa, fungi, most bacteria -- Photolithotrophs – Light + inorganic compound except CO2 ex. Plants and algae: producers of food and O2 for chemoheterotrophs II. ENVIRONMENTAL REQUIREMENTS A. TEMPERATURE 1. Psychrophiles -- cold loving microbes

2. Mesophiles --moderate-temperature loving organism -- most pathogens and indigenous flora 3. Thermophiles -- heat loving microbes -- ex. Thermophilic cyanobacteria found in hot springs -- Thermodurics: organisms that can survive or endure boiling--- ex. Endospores and viruses GROWTH TEMPERATURES: 1. Minimum Growth temperature - lowest temperature at which the species will grow 2. Optimum Growth temperature - temperature at which the species grows best

3. Maximum Growth temperature - highest temperature at which growth is possible B. pH -- acidity or alkalinity of a solution 1. Neutrophiles -- neutral growth medium (pH 7) -- most microorganisms 2. Acidophiles --prefer a pH of 2-5 --microbes that can live in the stomach 3. Alkaliphiles (Basophiles) --prefer pH greater 8.5 -- found in intestine

C. OXYGEN REQUIREMENTS -Based on relationship to O2 1. Aerobes---use molecular O2 for life and reproduction a. Obligate aerobes - require an atmosphere that contains O2 similar to room air (20-21% O2), Ex. Mycobacteria b. Microaerophiles - require O2 lower than room air (=5% O2) - ex. Neisseria, Campylobacter 2. Anaerobes - do not require O2 for life and reproduction - vary based on sensitivity to O2 a. Obligate anaerobe - unable to grow in O2, ex. Clostridium

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b. Facultative anaerobe - capable of surviving in the presence or absence of O2 (0% to 20-21% O2) - ex. Enterobacteria, streptococci, staphylococci c. Aerotolerant anaerobe - does not require O2 - grows better in the absence of oxygen but can survive in atmosphere containing O2 - ex. Lactobacilli Based on relationship to CO2 - Capnophiles– grow better in the presence of increased concentrations of CO2 - Anaerobes– Bacteroides, Fusobacterium - Aerobes– Neisseria,Campylobacter, Hemophilus

B. BACTERIAL GROWTH CURVE - Obtained from growing the organism in pure culture (in vitro) - growth of cells over time 1. LAG Phase - period of little or no cell division -bacteria absorbs nutrients, synthesize enzymes and prepare for reproduction - period of intense metabolic activity involving DNA and enzyme synthesis

2. LOG Phase -exponential growth phase or logarithmic growth phase - cells begin to divide and enter a period of growth or logarithmic increase - cellular reproduction is most active - growth rate is at its greatest - microorganisms sensitive to adverse conditions ex. Penicillin 3. STATIONARY Phase - period of equilibrium - during this phase that the culture is at its greatest population density - # of cells produced= # of deaths

4. DEATH phase - Logarithmic decline phase - # of deaths greater than the # of cells formed - toxic waste products increase and nutrient supply decrease

III. MICROBIAL GROWTH - An increase in the number of organisms Culture Media Requirements: 1. Contain the right nutrients 2. Must be initially sterile 3. Incubated at proper temperature Forms: 1. Liquid (broth)- infusion media 2. Agar– addition of a solidifying agent poured into tubes or Petri dishes

Blood agar

Types: 1. Synthetic Media - chemically defined medium - exact chemical composition is known - used for growth of chemoautotrophs and photoautotrophs and microbiological assays. 2. Complex Media - natural medium - contains digested extracts from animals, meats, fish, yeast and plants -used for growth of most heterotrophic bacteria and fungi

3. Enriched Media - broth or solid medium containing a rich supply of special nutrients that promote the growth of fastidious organisms (ex. Complex nutritional requirements) - add nutrients to the basic medium (nutrient agar) - ex. Blood Agar---nutrient agar + 5% sheep RBC Chocolate agar--- nutrient agar + powdered Hemoglobin - increase numbers of desired microbes to detectable levels

4. Selective media - suppress the growth of unwanted bacteria and encourage the growth of desired microbes - ex. Bismuth sulfite agar--- Salmonella typhi Mac Conkey’s agar– Gram- negative bacteria Thayer-Martin agar --- Neisseria Sabouraud dextrose agar--- fungi 5. Differential media - permits the differentiation of organisms that grow in the medium - ex. Mac Conkey’s Agar --- gram negative organisms lactose fermenters----pink colonies Non-lactose fermenters-- colorless

Salmonella culture

MacConkey’s agar

End of Lecture