microbio - intro Flashcards by zarieh Novela

Requires living host cells for growth thus they are the only obligatory intracellular organism among bacteria

Rickettsia and chlamydia

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Replicate only within cells
Inner core of either DNA or RNA but no cytoplasm
Depends on host cells for protein synthesis and energy generation
Fast mutation

Virus

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Ribosome subunit of bacteria

70s (50s and 30s)

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Ribosome subunits of fungi, Protozoa, helminths, animals and humans

80s (60s + 40s)

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Tetracycline inhibits what ribosomal unit?

30s

Buy AT 30, SEll at 50

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Erythromycin inhibits what ribosomal subunit of bacteria?

Inhibits 50s

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A single circular molecule of loosely organized DNA lacking a nuclear membrane and mitotic apparatus

Nucleiod

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Prokaryotes, especially bacteria doesn’t have true nucleus, rather they have..

NUCLEOID

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Single, covalently closed circle or a loop of double stranded DNA

Bacterial chromosome

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(+) peptidoglycan

(-) sterols

Prokaryotes

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(-) peptidoglycan

(+) sterols

Eukaryotes

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(+) sterols

Smallest bacteria

Mycoplasma

Mycoplasma genitalium (468 genes)

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They have chitin, which is a polymer of N-acetylglucosamine

Fungi

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They are determined by its rigid cell walls

Bacterial shape

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Determined by orientation and degree of attachment of bacteria at the time of cell division

Bacterial arrangement

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Murein or mucopeptide
Structural support and maintains the characteristic shape
Able to withstand media of low osmotic pressure

Peptidoglycan

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Backbone of peptidoglycan

Alternating n-acetylglucosamine and N-acetylmuramic acid molecules

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Bacteria that has thick peptidoglycan

Gram (+) bacteria

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Peptidoglycan synthesis is inhibited by..

Penicillin and cephalosporin

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Involved in cross-linking

D-alanine

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D-ala-D-ala is targeted by what antibiotic?

Vancomycin

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Enterococci is resistant to vancomycin because of different cross-linking sequence in the cell wall of the bacteria

D-ala-lactate

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Tears, saliva, and mucus has natural antimicrobial property

This enzyme cleaves the peptidoglycan backbone by breaking GLYCOSYL BOND

Lysozyme

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(+) teichoic acid; exotoxin

Gram positive

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(-) teichoic acid; endotoxins

Gram negative bacteria

Site of beta-lactamases

Periplasmic space

Acid-fast bacteria

Mycobacteria

Mycobacteria is an acid fast bacteria, resisting decolorization with an acid alcohol after being stained by carbolfuchsin. What component contributes to this property?

Mycolic acid

True or false: pathologic effects of endotoxins are similar irrespective of organism

True

Responsible for toxic effects of endotoxins. Found in LPS in OM.

Lipid A

Found in the outer layer of gram positive bacteria Antigenic, induce ab that are SPECIES-SPECIFIC mediates the adherence of staph to mucosal cells

Teichoic acid

Teichoic acid is a polymer of (2)

Glycosyl phosphate and ribitol phosphate

Invagination of cytoplasmic membrane

Mesosome

Functions as the origin of the transverse septum that divides the cell on half and as the binding site of DNA bacterial ribosomes

Mesosome

Basis of the selective action of several antibiotics

Differences in ribosomal RNAs and proteins

Reserve of high energy stored in the form POLYMERIZED METAPHOSPHATE.

Volutin granules

Gelatinous layer covering the entire bacterium | Composed of polysaccharide

Capsule

Capsule of bacillus anthracis is not composed of polysaccharide, it is composed of..

Glutamic acid

Functions of capsule

Virulence Identification Adherence Antigen in vaccine

One of the ways to visualize capsules, where it swells in the presence of homologous antibodies

Quellung reaction

The energy for flagellar movement provided by ATP

Proton-motive force

Flagellum-like structure that provides undulating motion for spirochetes

Axial filament

Axial filament. Counterclockwise rotation - ? Clockwise rotation -?

Counterclockwise rotation - directed motion | Clockwise rotation - tumbling

A polysaccharide coating secreted by many bacteria | Adhere to various structures such as on the surface of teeth by strep.mutans

Glycocalyx or slime layer

Highly resistant structures formed in response to adverse conditions

Spores

Spore-forming bacteria

Clostridium and bacillus

Occurs when nutrients (c and n) are depleted

Sporulation

Spores contains their own DNA | What structure Coats the spores?

Dipicolinic acid (calcium chelator)

Spores can be destroyed by this steam heating

Autoclaving at 121C for 30 min, psi of 15

Bacterium that is an obligate parasite

Treponema PALLIDUM

Obligate intracellular parasite of plants

Viroids

Bacteria produced by this process in which one parent cell divides to form 2 progeny cells

Binary fission

Major determinant of growth of bacteria

Nutrients

4 phases of bacterial growth cycle

1) lag phase 2) log phase 3) stationary phase 4) death phase

In what phase in bacterial growth cycle occurs a vigorous metabolic activity where cells do not divide yet.

Lag phase

In what phase in bacterial growth cycle when there is rapid cell division

Log phase

In what phase in bacterial growth cycle when there is nutrient depletion or toxic products slow down growth until the number of new cells produced balances the cells that die (Living=death)

Stationary phase

In what phase in bacterial growth cycle when there is a marked decline on the number of viable bacteria.

Death phase

Oxygen generates 2 toxic molecules

Hydrogen peroxide | Superoxide radicals

Obligate anaerobes

Actinomyces Bacteroides Clostridium

Facultative anaerobes

``` Corynebacterium L monocytogenes Mycoplasma B. Anthrax Staphylococcal ```

Microaerophilic

Campylobacter, helicobacter Spirochetes (borrelia and treponema) Streptococcus

Obligate aerobes

Nosy nagging pets must breathe lots of oxygen ``` Nocardia Neisseria Pseudomonas Mycobacteirum, mycoplasma pneumoniae Bordatell, brucella, bacillus cereus Legionrlla, leptospira ```

Growth at 4C

Y. Enterocolitica | L. Monocytogenes

Bacteria that grows in amoeba in streams

Legionella

Bacteria that grow well in tap and distilled water

Psedomonas

Virioids has naked RNA or DNA?

RNA

Jumping genes

Transposons

Produce igA protease

N. gonorrheae and meningitidis | H. Influenzae type B

Mobile genetic elements. | Dna pcs that move readily from one site to anothrr eitrhr within or bw dna of bacteria, plasmids and bacteriophahe

Transposons Hence codes for drug resistance and mutations

Naked proteins with the same aa sequence but have folded differently

Prions

Prion is a normal part of brain. They have alpha helical structure. It become pathologic if

Beta sheet and forms amylod fibrils

Appearance of vacuolated neurons with loss of function and lack of imminr response or inflammation

Spongiform encephalopathies

To prevent prion dse, how to disinfect it properly?

5% hypochlorite soln 1. 0M Na hydroxide Autoclave 15 psi for 1 hr

Membrane disrupting exotoxins

Pore-forming cytolysin

Pore forming cytolysin

Alpha toxin by staph aureus

A membrane disrupting bacterial exotoxins which contain lecithinase showing a double zone of hemolysis.

Cl. Perfringens alpha toxin

Exotoxins that binds to MHC II receptors | Non specifically activates large number of T cells

Superantigen exotoxins

Superantigen exotoxins examples

Toxic shock syndrome toxin (TSST) by staph aureus | Strep pyogenes exotoxin A (SPE-A)

Component of exotoxin which internalize and inhibits a specific critical intracellular function causing damage to the cell. It is the active toxic portion of toxin

A component

Component of exotoxin that binds to specific cell surface receptors and initiates internalization of the A component. It determines what cell type each toxin damages.

B component

A-B toxin that inhibits protein synthesis (5)

``` Diptheria toxin Exotoxin A Shigella toxin Shigalike toxin Verotoxin ```

A-B toxin that inhibits protein synthesis: | Diptheria toxin

EF-2 inhibitor

A-B toxin that inhibits protein synthesis: | Shiga toxin

Of shigella dysenteriae type I | A component cleaves 60s ribosomes

A-B toxin that inhibits protein synthesis: | Verotoxin

Of e.coli serotype O157:H7 Inactivates protein synthesis by removing adenine from the 28s rRNA Causes bloody diarrhea

A-B toxin that increase cAMP

Labile toxin Anthrax toxin Pertussis toxin Choleragen

Toxin of enterotoxic e.coli | Internalize A component to ADP-ribosylates Gs, which activates an adenylcyclase that produces high level of cAMP

Labile toxin

Components of anthrax toxin

``` Protective Antigen (PA) that serves as B component Edema factor (EF) that activates adenylcyclase Lethal factor (LF) kills cell ```

Toxin that inhibits Gi which is the negative regulator of adenylcyclase thru ADP ribosylation thus increasing cAMP

Pertussis toxin

Toxin of vibrio cholerae Catalyzes ADP-ribosylation of Gs protein ECG activates adenylcyclase that produces high level of cAMP, thus increases water and acid secretion

Choleragen

Neurotoxin of Cl. Tetani which act on cns, inhibiting the inhibitory transmitter GABA

Tetanospasmin

Neurotoxin of Cl. Botulinum that acts on peripheral synapses, blocking the release of neurotransmitters

Botulinum toxin

Bacteria that escapes macrophage and grow inside them

``` RuMBLeS Rickettsia mycobacteria Brucella listeria shigella ```

Bacteria that invades the Peyer's patches thru the phagocytic M cells

Shigella

Linear pcs of DNA

Exogenates

Exchange of two nearly identical pcs of DNA

Homologous recombination

Homologous recombination requires what protein

Rec A protein

Processes of DNA transfer on bacteria

Conjugation, transformation, transduction

Transfer of naked forms of DNA which occurs in same sp of bacteria

Transformation

Bacteria infected by virus

Bacteriophage

Transfer of DNA directly from one living bacterium to another. Bacterial sex. Major mechanism for transfer of antibiotic resistance.

Conjugation

Transfer of bacterial genes via phage vectors

Transduction

It a liquid or gel designed to support the growth of microorganisms or cells.

Growth medium or culture medium

Different types of media for growing different types of cell

``` Differential media Enriched media Nutrient media Transport media Selective media ```

``` Growth media used for the growth of only selected microorganisms. An antibiotic (by which the selective microorganisms is resistant) is added to the medium in order to prevent other cells, which do not posses the resistance, from growing. ```

Selective media

Growth media that distinguishes one microorganism type to another. This uses biochemical characteristics of the microorganism growing in the presence of specific nutrients or indicators

Differential or indicator media

Examples of differential media

``` Blood agar Eosin methylene blue EMB MacConkey Mannitol salt agar MSA X-gal plates ```

Differential media that is used in strep test, contains bovine heart blood that becomes transparent in the presence of hemolytic streptococcus

Blood agar

Differential media for lactose and sucrose fermentation

EMB

Differential media for lactose fermentation

Macconkey

Differential media mannitol fermentation

Mannitol salt agar

Differential media for lac Operon mutants

X-gal plates

Criteria of transport media (5)

1) temporary storage of specimens 2) maintains specimen's viability without altering their conc 3) contains buffers and salt only 4) lacks C, N and other GF so as to prevent microbial multiplication 5) in isolating anaerobes, must be free from molecular oxygen

Examples of transport media

Thioglycolate Stuart transport medium Venkat-ramakrishnan medium

Transport media that uses broth for strict anaerobes

Thioglycolate

Transport media that has a non-nutrient soft agar gel containing a reducing agent to prevent oxidation, charcoal to neutralize

Stuart transport medium

Transport media for vibrio cholera

Venkat-ramakrishnan medium

Growth media commonly used to harvest as many different types of microbes as are present in the specimen. Contains nutrients required to support the growth of wide variety of organisms.

Nutrient media

Examples of nutrient media

Blood agar | Chocolate agar

Enriched media in which nutritionally rich whole blood supplements is the basic nutrient.

Blood agar

Enriched media that contains heat-treated blood (40-45c) which turns brown

Chocolate agar

Growth media which is the source of AA and N (beef,yeast extracts) An undefined medium because AA source contains variety of cmpds with the exact composition being unknown Contains all the elements that most bacteria needed for growth and are non selective

Nutrient agar

Undefined medium (aka basal or complex medium) contains: (3)

1. C source 2. Water 3. Various salts

Defined medium (aka chemically defined medium or synthetic medium) contains:

1. All chemical used are known | 2. No yeast, animal or plant tissue present

Examples of defined media

Nutrient agar medium Peptone Agar

Nutrient agar medium composition

Beef extract- 0.3g (mineral and carbo)

Peptone composition

0. 5g protein and N source | 0. 5g NaCl as electrolyte

Agar composition

1.5g solidifying agent 100ml distilled water pH 7

Growth media that contains minimum nutrients possible for colony growth. Often used to grow wild type microorganism. Used to select or used against recombinants or exconjugants

Minimal media

Minimal media contains

Carbon source (succinate) Salts (Mg, N, P) Water

Type minimal media the contains a single selected agent, usually AA or sugar. This allows the culturing of specific lines of auxotrophic recombinants

Supplementary minimal media

Selective and differential bacterial media: | Buffered charcoal-yeast extract (BCYE) agar

Legionella

Selective and differential bacterial media: | Chocolate agar

Haemophilus and neisseria for sterile area

Selective and differential bacterial media: | EMB or MacConkey

Enteric bacteria

Selective and differential bacterial media: | Hektoen enteric agar

Salmonella and shigella sp

Selective and differential bacterial media: | Loeffler's and tellurite medium

Corynebacterium diptheria

Selective and differential bacterial media: | Lowenstein Jensen

Mycobacterium tuberculosis

Selective and differential bacterial media: | Thayer-Martin or New York City agar

Neisseria with area of normal flora

Selective and differential bacterial media: | Regan-Lowe

Bordetella pertussis

Selective and differential bacterial media: | TCBS (alkaline medium)

Vibrio cholerae

Catalase (+) Coagulase (+) forms golden yellow colonies Mannitol (+)

Staph aureus

Major protein in the cell wall of staph aureus which binds to Fc portion of IgG

Protein A

Mediates the adherence and phage typing in staph aureus

Teichoic acid

Staph aureus is a normal flora of..

Nose

Typical lesion of staph aureus

Abscess

Toxins of staph aureus and its manifestations

Enterotoxin: vomiting, watery and nonbloody diarrhea TSST: asso with tampon use, superantigen Exfoliatin: phage II staph, scalded skin syndrome, superantigen Alpha toxin: skin necrosis

Diseases caused by staph aureus (6)

``` Mastitis Blepharitis Cellulitis Osteomyelitis Food poisoning TSS ```

Coagulase (-)

Staph epidermidis and staph saprophyticus

Staph epidermidis is the normal flora of...

Skin and mucus membrane

Staph epidermidis is ____ sensitive

Novobiocin

Disease caused by staph epidermidis

IV catheter infections | Endocarditis on normal prosthetic heart valves

Treatment for staph epidermidis

Vancomycin

Treatment for staph aureus

Prp Vancomycin (if methicillin or nafcillin resistant) Clindamycin Nafcillin or cloxacillin (if beta lactamases resistant)

Staph that causes UTI in sexually active women | 2nd to e.coli

Staph saprophyticus

Treatment for strep saprophiticus

Quinolones | Trimethoprim-sulfamethoxazole

Lancet shape diplococci

Strep pneumoniae

Hemolytic activity of strep pneumoniae

Alpha hemolytic

Strep pneumonia does not live in the presence of...

bile and optochin

Strep pneumoniae is encapsulated thus exhibits what reaction

Quellung reaction

Strep pneumoniae produces this enzyme causing mucosal colonization

IgA protease

Green zone, incomplete hemolysis

Alpha hemolytic

Clear zone, complete hemolysis

Beta hemolytic

Enzymes of beta hemolytic

Streptolysin o and S (hemolysin)

No hemolysis

Gamma hemolytic

Determines group of beta hemolytic strep

C carbo

Most important virulence factor of streps | Provides type specific immunity

M protein

Test in lancefield classification

Precipitin test

Group a strep

Strep pyogenes

Strep pyogene is sensitive to..

Bacitracin

Strep pyogenes causes what disease.

Pharyngitis

Strep pyogenes has what type of capsule

Hyluronic acid capsule

A selective differential agar used to isolate and identify member of enterococcus

Bile esculine agar

Most common bacterial resident of large intestine

Bacteroides

Most common resident of upper respiratory tract

Alpha hemolytic strep and neisseria

Normal flora of conjunctiva

Diptheroids, staph epidermidis and non hemolytic strep

What is the type of sex pili used for bacterial conjugation

Type VII

Cross linking enzyme on the surface of bacteria which is targeted by beta-lactam antibiotics

Transpeptidase

Is cell wall or cell membrane antigenic?

Yes

transport enzyme and oxidative phosphorylation

Plasma membrane

Contains gene for toxins and antibiotic resistance

Plasmid

Inclusion bodies formed when source of N, S, P are depleted and there is excess C

Poly beta hydroxybutyric acid (PHB acid)

Cytokines that cause fever

TNF, IL-1, IL-6

Breaks down the beta 1->4 bonds between NAM and NAG

Lysozyme

Partial cell wall lysozyme digestion

Spheroplast

Complete cell wall lysozyme digestion

Protoplast

Inhibits enolase

Fluoride ion

Enzyme reaction that produces H2O2 + O2

Superoxide dismutase

Enzyme reaction that produces H2O + O2

Catalase

Enzyme reaction that produces ClO + H2O

Myeloperoxidase

Enzyme reaction that produces O2 + H + NADP

NADPH oxidase

Non SI unit for sedimentation rate

Svedberg unit

Svedberg unit is a measure of time, wherein a given particle of a given size and shaape travel to the bottom of the tube under centrifugal force. It is defined exactly how many seconds?

100 fs or 10^-13s

All bacteria have no sterol, instead they have peptidoglycan. What is the only bacteria which has Sterol?

Mycoplasma. | No cell wall

Thermally dimorphic fungi

Molds at culture medium and room temperature | Yeast at infected tissue