-prokaryotes (bacteria)

-fungi - yeast, mold

-protozoa

-helminths - worms

coccus (pl. cocci) - spherical

bacillus (pl. bacilli) - rods

spirals

diplococci - pairs

streptococci - chains

tetrad - groups of 4

sarcinae - cubelike groups of 8

staphylococci - grapelike clusters

*strep (small) *staph (big)

diplobacilli - form pairs

streptobacilli - chains

coccobacilli - ovals

pallisades - look like Chinese letters (ex Diphtheria)

vibrio - curved

spirilla - helical, like a corkscrew with rigid bodies

spirochetes - flexible corkscrews

monotrichous - one

amphitrichous - tufts at both ends

lophotrichous - 2 or more at 1 end

peritrichous - flagella all over cell

- semi rigid

- protects against lysis

- protects internal structures

- usually made of peptidoglycan

- Thick, many layers of peptidoglycan outside the plasma membrane

- Resists decolorization when gram staining

- Contain teichoic acid (allows for slide agglutination typing)

- One, or just a few peptidoglycan layers outside the cell membrane

- Easily broken

- No teichoic acids

- Have outer membrane of phospholipid bilayer, used to determine strain or serovar

- Barrier for some antibiotics, enzymes, heavy metals, bile salts

No cell walls - Mycoplasma

Acid Fast cell walls - Mycobacterium (have a waxy lipid called "mycolic acid" in cell wall, resists staining. Must use heated carbolfuchsin)

-what it looks like

-macroscopic & microscopic

-gram staining (+/-)

- acid fast (mycobacterium)

negative staining

-used to determine which enzymes an organism has

-must have pure culture

antigen-antibody reaction

-slide agglutination

-ELISA (Enzyme Linked ImmunoSorbent Assay)

contain DNA from a known organism

DNA strand is separated

-look to see if it hybridizes (forms base pairs with the unknown specimen, if it does, have identified specimen)

-works on mixed cultures

used to map nucleotide sequences

sometimes used to determinte the source of a nosocomial infection

Cat Scratch Fever

normal flora in cat intestines

serious infection - high fever

gram negative rods

direct contact or fleas

Pertussis  - Whooping Cough

gram negative rods

vaccine DPT

forms a membrane in the throat

gram negative diplococci

normal flora of mucus membranes

N. gonorrheae - gonorrhea

N. meninginitidis - meningitis

*N. gonorrheae has protein Opa that binds to CD4 lymphocytes and prevents the production of memory cells and immunity

gram negative motile rods

can grow in water, on soap, in bottle caps

can grow in refrigerator

common nosocomial infection

can produce a blue-green pigment that smells like grapes

antibiotic resistant - gentamicin

inhabits mammalian interstinal tract

wound infections & UTI

E. coli O157:H7 - causes diarrhea and produces a toxin that can shut down the kidneys

-2400 serovars

-found in intestinal tracts of poultry & cattle, found in reptiles

-can get inside plants we eat

-causes bloody diarrhea

-causes typhoid fever

-high fever & headache

-can infect the liver & spleen

-some people become carriers (Typhoid Mary)

-many flagella

-swarming growth on media

-normal intestinal flora

-UTI & wound infections

-smells like chocolate cake

-wound infection from cat bites

-requires IV antibiotics

-causes cellulitis

-needs chocolate (hemolyzed blood) agar to grow in the lab

-very pathogenic

-smells mousey

Helicobacter spp.

Helicobacter pylori

-spore forming anaerobes

-spores can live in the soil for years

C. tetani - tetanus (lockjaw)

C. botulinum - botulism

C. perfringens - gas gangrene

C. difficile - antibiotic resistant, normal intestinal flora, when antibiotics kill all good flora it takes over, often a nosocomial infection

CDC must be notified

Three types of anthrax:

-Cutaneous (skin)

-Gastrointestinal

-Pulmonary

(if not treated can lead to septicemia - death rate 100%)

*potential for bioterror

-gram positive cocci

-grows in grape-like clusters

-yellow colonies

-can grow in salty meats

-grows in ocean

-produces toxins

-MRSA (pg 422)

-causes wound infections, food poisoning, toxic shock syndrome

Streptococcus - beta hemolytic - Group A -

Streptococcus pyogenes

Group A

Strep. pyogenes

has M protein on surface that helps it avoid phagocytosis

causes most variety of diseases:

sore throats

scarlet fever

rheumantic fever (affects joints & heart)

impetigo

necrotizing fascitis - painful infection that can consume an inch of tissue an hour

grows in soft cheeses & deli meats

withstands refrigeration

should not be eated by pregnant women

can cause stillbirth

-resist gram stain because they have waxy cells

-cells have mycolic acid

-require acid fast stain (carbol-fuchsin)

M. tuberculosis - tuberculosis

M. leprae -leprosy

coiled gram negative

move using axial filaments

Treponema pallidum - syphilis

Borrelia spp. - Lyme disease

YEAST

pseudohyphae

chains of buds that do not detatch

made by Candida albicans (causes thrush)

-systemic - can spread within body

-subcutaneous - under the skin
(ex. Sporothrix schenckii - causes sporotrichosis in punture wounds, common in farmers)

-superficial - fungi that infect hair, nail, and skin are called dermatomycoses

-unicellular

-some can form a cyst and survive outside a host

-most reproduce asexually

malaria life cycle

The life cycle of malaria parasites in the human body. A mosquito infects a person by taking a blood meal. First, sporozoites enter the bloodstream, and migrate to the liver. They infect liver cells (hepatocytes), where they multiply into merozoites, rupture the liver cells, and escape back into the bloodstream. Then, the merozoites infect red blood cells, where they develop into ring forms, trophozoites and schizonts which in turn produce further merozoites. Sexual forms (gametocytes) are also produced, which, if taken up by a mosquito, will infect the insect and continue the life cycle. 

-transmitted from cats to humans by fecal-oral contact

-can cause birth defects if mom has her first exposure in the 1st trimester

-causes toxoplasmosis

-flat, leaf-shaped bodies

-oral sucker

-can infect:

lungs - Paragonimus westermani (worldwide)

liver - Clonorchis sinensis (immigrant populations)

blood - Schistosoma spp. (worldwide)

-intestinal parasites

-the head is called the scolex that attaches to the intestines

-they do not digest the host tissue but absorb undigested food

-the body made of proglottids

-proglottids contain the male and female structures that produce eggs

makes up the body of a tapeworm

contains male and female structures that produce eggs

-obligate intracellular parasites

-have DNA or RNA, not both

-may be single or double stranded

-nucleic acid are covered with a coat made of protein called the capsid

-capsid made of sub-units called capsomeres

-some have an outer envelope

-virus = nucleic acid

-virion = nucleic acid + capsid + envelope

-envelopes may have spikes that help them attach to host cells

-spikes may cause hemagglutination (lysis of red blood cells) (ex: influenza)

-covers the nucleic acid in a virus

-made of protein

virus = nucelic acid

virion = nucleic acid + capsid + envelope

some viruses have envelopes with spikes

helps them attach to host cells

spikes may cause hemagglutination

-must use living cells

-animals (mice)

-cell cultures from animal cells

-embryonated (fertile) eggs

-animal cells grown in a nutrient solution adhere to walls of container

-a virus is introduced

-it causes the cells to deteriorate and is called the cytopathic effect (CPE)

-two types of cell cultures

-primary: includes diploid cell lines from embryo, live for ~100 generations

-continuous cell lines: from cancer cells, "immortal" (HeLa)

viral multiplication - bacteriophages

2 types are:

-lytic cycle

-lysogenic cycle

viral multiplication - bacteriophages

LYTIC CYCLE

1. attachment - virus attaches to cell wall or cell membrane proteins
2. penetration - viral DNA or RNA is injected
3. biosynthesis - replicate in cytoplasm ribosomes
   -virus stops host protein synthesis by: destruction of host DNA or interfering with transcription or translation
   -uses host ribosomes and nucleotides to replicate
   -capsid proteins are made, but all the parts are separate
   -this is called the eclipse period
4. maturation - virions are assembled
5. host cell lyses and many viruses are released

viral multiplication - bacteriophages

LYSOGENIC CYCLE

1. DNA or RNA penetrates the cell
2. the viral DNA inserts itself into the host DNA and does not replicate (latency)
3. viral DNA is incorporated into cell progeny
4. when conditions are right, the lytic cycle occurs

1. attachment to proteins or glycoproteins on cell membrane
2. entry into the cells is by endocytosis or fusion (viral envelope fuses with plasma membrane and the capsid)
3. uncoating - enzymes separate the nucleic acids from the protein coat
4. biosynthesis - A: DNA viruses replicate their DNA in the nucleus and their capsid proteins in the cytoplasm
   B: RNA viruses multiply in the host cells cytoplasm
5. maturation - assembly of capsid and virion
6. release - A: budding - viral capsid with enclosed nucleic acids pushed through the plasma membrane. The plasma membrane is now the virus's envelope. May not kill host cell
   B: Non-enveloped viruses exit through ruptures in the host's cell. Usually kills the cell

-infectious particle made of protein

-misfolded protein

-can survive autoclaving (steam under pressue of 120 degrees C for 20 minutes)

-must be killed by incineration

-temperature (up to a point)

-pressure (increases)

-increased concentration

-enzymes speed the rate

-pH must be "optimal"

-proteins that speed chemical reactions by lowering the activation energy without being changed

-allow reactions to occur at a temperature that is compatible with life

-most enzymes end in "ase"

-only catalyze one reaction

-they are large, three dimensional proteins with a primary, secondary, tertiary, quarternary structure

(primary-sequence amino acids, secondary-alpha helix and b pleated sheets, tertiary-unique 3D structure caused by folding by interaction of side chains, quarternary-two or more proteins)

-only one area with its specific substrate (lock and key)

-the end product of an enzymatic reaction binds to an allosteric site on the first enzyme in the reaction

-this changes the shape of the active site so the first enzyme can no longer function

an area of an enzyme that is NOT where the enzyme binds to the substrate

(changes shape of enzyme, substrate unable to bind)

-reactions with enzymes occur 1 billion times faster than reactions without them!

-one enzyme can catalyze up to 500,000 reactions per second

-some enzymes act alone

-some need a helper

binds to the active site of the enzyme and blocks the substrate from binding.

It competes for the active site of the enzyme, so the rate of reaction is dependent on the concentration of substrate and the concentration of inhibitor

-the protein part is called an apoenzyme

-the other part is called a cofactor

-many cofactors are minerals like iron, zinc, magnesium, and calcium

-"feed a cold, starve a fever"

-colds caused by viruses

-fevers often caused by bacteria

-fever makes environment unfavorable to bacteria that are infecting you

-liver sequesters iron and zinc (cofactors for bacteria) when we have a fever

-a cofactor is called a coenzyme if it is an organic molecule

-conenzymes are usually a vitamin

-ex: niacin - vitamin B3 is part of the coenzymes NAD+ (in catabolic reactions) and part of NADP+ (in anabolic reactions)

-they are electron carriers

-ex: riboflavin - vitamin B2 is part of the coenzymes FMN + FAD which are also electron carriers in cellular respiration

ex: pantothenic acid - another B vitamin is part of CoA in the Krebs cycle in cellular respiration. It is ubiquitous (everywhere)

They are all involved in obtaining energy from food

-obligate aerobes - require O2

-microaerophiles - require O2 but in concentrations lower than air

-faculative anaerobes - use O2 but can survive without it

-capnophiles - aerobes that require O2 and a high CO2 atmosphere

-obligate anaerobes - do NOT require O2, and many are harmed by it

-aerotolerant anaerobes - do not use O2 but tolerate it

some obligate anaerobes use O2 and produce hydrogen peroxide (H2O2) which kills them because they don't make catalase which breaks down H2O2

-stop the growth of some bacteria to isolate others

ex - Sabouraard's Dextrose agar pH=5.6

-this inibits most bacteria and allows fungi to grow

ex - mannitol salt

-inhibits most bacteria except Staphylococcus

help to distinguish pathogenic bacteria by looking for special colony characteristics

ex-mannitol salts-differentiates Staph. aureus from other Staph. organisms - S. aureus ferments the mannitol turning the medium yellow

ex-Beta hemolytic Strep. Group A-O make a clear ring around their colon on blood agar

ex-Salmonella are black on peptone ion agar 

-antagonism

-symbiosis

competition between normal flora and pathogens

ex. - E. coli produces proteins that inhibit the growth of Salmonella and Shigella

ex. - Acidophilis spp. lower the pH of the vagina to ~pH 4 so yeast cannot grow

-competing for nutrients

-producing harmful substances

-affecting pH

-affecting oxygen availability

-yeast (Candida) may colonize the mouth and vagina

-Clostridium difficil can infect the intestines (common nocosomial infection)

-commensalism

-mutualism

-parasitism

live bacteria that are ingested or applied that have a beneficial effect

ex - lactic acid bacteria in the intestine inhibit growth of pathogens

-suitable location: bacteria in the intestine can cause infection when in the urinary tract or wounds

-immunosuppressed state: chemotherapy or AIDS. Organism normally present become pathogenic

-after broad spectrum antibiotics

A) some diseases are only caused by one organism (ex. syphilis-Trepanoma pallidum, leprosy-Mycobacterium leprae, tetanus - Clostridium tetani)

B) some dieases can be caused by many different organisms (pneumonia, UTIs, sepsin, meningitis)

humans

animals (zoonoses)

soil

water

Pasturella multocida - cat bites

Rabies - mammals

Malaria - mosquitoes

Tularemia -hamsters

Tapeworms

Leprosy - armadillos

tetanus

Necator americanus (hookworm)

Strep. pyogenes makes M protein that helps attachment and avoid phagocytes

Neisseria gonorrhoeae has protein called Opa to attach, invade, and grow inside WBC. Opa attaches to CD4-lymphocyte, it prevents production of "memory cells" (lifelong immunity where we "remember" antigens we were exposed to)

Mycobacterium have waxy cell wall (mycolic acid) to resist phagocytosis

coagulase

streptokinase

hyaluronidase

collagenase

Staph makes coagulase

coagulase causes the formation of fibrin clots which wall off the infection

Strep. pyogenes (Group A Strep) makes streptokinase which breaks clots and helps infection spread

streptokinase is given to heart attack and stroke victims to prevent formation of clots.

Blood vessels get plaque made of cholesterol, fat, fibrin, and calcium. Platelets stick to plaque and initiate clot formation which contains fibrin. Streptokinase helps break up fibrin. (now TPA (tissue plasminogen activator) is used)

made by Strep. and Clostridium

hyaluronidase digests hyaluronic acids

hyaluronic acids holds cells together

hyaluronidase destroys tissue to help infection spread

Clostridium makes collagenase

collagenase destroys collagen, destroys tissue, & keeps antibiotics away (destroys blood vessels through which antibiotics travel to reach infection)

antigens trigger antibody production - proteins, sugars, nucleic acids

Antigenic variation - some pathogens can change surface antigens and our antibodies no longer recognize them

ex. Influenza, AIDS, Neisseria

-secreted actively from viable microbes (on the inside)

-heat labile, protein

-high specific activity

-very toxic

-toxoidable - can be denatured to remove toxicity and retain antigenicity (ex. to make vaccine)

-part of the bacterial architecture (on the cell wall)

-heat stabile, lipid/sugar

-low specific activity

-variable toxicity

-nontoxoidable - chemical composition prohibits molecular modification