Biol 237 Microbiology Final - SVSU

cell wall

lies outside the cell membrane in nearly all bacteria

functions of cell wall

-maintains shape

-prevents the cell from bursting when fluids flow in by osmosis

peptidoglycan

most important component of the bacterial cell wall

a large polymer

made of amino acids and 2 kinds of sugars

2 kinds of sugars

NAM (N-acetylmuramic acid)

NAG (N-acetylglucosamine)

Lipopolysaccharide

-also called endotoxin

-important part of the outer membrane and can be used to identify Gram-negative bacteria

-not released until the cell walls of dead bacteria are broken down

capsule

-a protective structure outside the cell wall of the organism that secretes it

-consists of complex polysaccharide molecules

glycocalyx

all polysaccharide-containing substances found outside of the cell wall

periplasmic space

the gap between the cell membrane and cell wall

represents a very active area of cell metabolism

flagella

long, thing, helical appendages used for movement

pilus

tiny, hollow projections that are used to attach bacteria to surfaces

NOT involved in movement

endospore

-resting stages

-also known as spores

-helps organism survive because it is a response to poor environment

-formed within cells and highly resistant

-used by terrorists

endotoxin

also know as Lipopolysaccharide (LPS)

found in Gram negative bacteria

transformation of bacteria

a change in an organisms characteristics because of the transfer of genetic info

plasmid

a small, circular, independently replicating piece of DNA in a cell that is not part of its chromosome and can be transferred to another cell

virulence plasmid

-are in Salmonella or the neurotoxin genes carried on plasmids in C. Tetani

-cause disease signs and symptoms

envelope

a bilayer membrane found outside the capsid of some viruses, acquired as the virus buds through one of the hosts membranes

capsid

the protein coating of a virus which protects nucleic acid core from the environment and usually determines the shape of the virus

retrovirus

an enveloped RNA virus that uses its own reverse transcriptase to transcribe its RNA into DNA in the cytoplasm of the host cell

95% of patients get Leukemia

prion

a very small infectious particle consisting of protein without any nucleic acid

oncogene

cancer causing gene

proto-oncogene

a normal gene that can cause cancer in uncontrolled situations; often the normal gene comes under the control of a virus

latent infection

an infection typical of herpesviruses in which an infection in childhood that is brought under control later in life is reactivated

persistent infection

the continued production of viruses within the host over many months or years

lytic infection

the cell becomes filled with a hundred or more phages, phage enzymes rupture the cell and release newly formed phages which can then infect other cells. the cell is then destroyed

phages

infect bacterial cells and reproduce within them

made up of a core of nucleic acid covered with protein

RSV

Respiratory Syncytial Virus

cause of lower respiratory infections affecting children under 1 year old

causes cells in culture to fuse their plasma membranes and become multinucleate masses

Streptococcus pyogenes

causes Scarlet fever and strep throat

virulence

the degree of intensity of the disease produced by a pathogen

size of a virus

10-100 nanometers

100x smaller than bacteria

size of a bacteria

1-10 microliters in size

host range

the spectrum of hosts that a virus can infect

specificity

the spectrum of cell types that a virus can infect

structure of viruses

-capsid: nucleic acid

-nucleocapsid

-envelope

morphology of virus

-helical viruses

-icosahedron: 20 or more sides

-complex viruses: cannot describe a specific shape (ex. Ebola)

transformation

contact inhibition is lost and cells divide endlessly

metastasis can occur - migrate from one organ to another = deadly

Viruses associated with tumors

Adult T-cell Leukemia

Burkitt's Lymphoma - Epstein Barr

Skin and Cervical Cancer - Papilloma

Liver cancer - Hepatitus B and C

positive stranded RNA viruses (Picornavirus Family)

-non-enveloped and small

-poliovirus

-rhinovirus

-Hepatitis A - now have a vaccine

Rhinovirus

common cold

115 types

Negative stranded RNA viruses

Rhabdovirus

Paramyxovirus

Orthomyxovirus

Rhabdovirus

rabies

Paramyxovirus

mumps, measles, RSV

Orthomyxovirus

influenza

benefits of yearly vaccination

prevent new strain of flu virus by antigenic drift and shift

provides the highest immunity

provides protection to those nearby

double stranded RNA virus

reovirus to rotavirus

causes diarrhea and sometimes death if untreated

non-enveloped, icosahedral

Herpes Viruses (Double stranded DNA)

Chicken pox and shingles

Herpes simplex I (upper) and II (lower)

mononucleosis

TORCH screening

during pregnancy, mother is screened using this to search for virus infection that causes teratogenesis

T: Toxplasma gandii

O: Other infections

R: Rubella

C: Cytomegalovirus

H: Herpes simplex

Use of PCR

-detect trace amount of nucleic acid in forensic medicine

-diagnose the pathogen by detecting the unique genes in a pathogen

-detect the amount of virus in the blood of the patient

-produce large quantity of DNA for analysis

Koch's Postulates

1. The specific causative agent must be found in every case of the disease

2. The suspected organism must be isolated in pure culture

3. Inoculation of a sample of the culture into a healthy, susceptible animal must produce the same disease

4. The organism must be recovered from the inoculated animal

bacterial growth curve

lag phase: no increase in numbers

log phase: increase of bacterial population

controlled by amount of nutrients provided at a certain time interval

factors affecting bacterial growth

obligate anaerobe

obligate aerobe

facultative anaerobe

micro aerobe

obligate anaerobe

can only grow without oxygen

obligate aerobe

can only grow with oxygen

facultative anaerobe

oxygen is not important

micro aerobe

grows with a little bit of oxygen

factors affecting pathogen growth

mesophile

thermophile

mesophile

thrives at medium temperature

thermophile

thrives at extremely high temperatures

interferon

a small protein often released from virus-infected cells that binds to adjacent uninfected cells, causing them to produce antiviral proteins that interfere with viral replication

transplant rejection

destruction of grafted tissue or of a transplanted organ by the host immune system

attenuation

the weakening of the disease-producing ability of an organism

invasiveness

the ability of a microorganism to take up residence in a host

tetanus

disease caused by c. tetani in which muscle stiffness progresses to eventual paralysis and death

toxoid

an exotoxin inactivated by chemical treatment but which retains its antigenicity and therefore can be used to immunize against the toxin

classes of antibodies

IgA

IgG

IgE

IgM

IgA

found in the blood and secretions

IgG

main class of antibodies found in the blood; produced in large quantities during secondary response

IgE

binds to receptors on basophils in the blood or mast cells in the tissues

responsible for allergic or immediate hypersensitivity reactions

B cell or B lymphocyte

produced in and matures in bursal-equivalent tissue, it gives rise to antibody-producing plasma cells

botulism

disease caused by C. botulinum, it is the most common form, foodbourne botulism

it results from ingestion of preformed toxin and is an intoxication instead of an infection

enterotoxin

exotoxin that acts on tissues of the gut

enterovirus

one of the three major groups of picornaviruses that can infect nerve and muscle cells, the respiratory tract lining, and skin

neurotoxin

a toxin that acts on nervous system tissues

nosocomial infection

an infection acquired in a hospital or other medical facility

macrophage

phagocytic leukocytes found in tissues

opsonization

the process by which microorganisms are seen as more attractive to phagocytes by being coated with antibodies and C3B complement protein

notifiable disease

disease that a physician is required to report to public health officials

complement

a set of more than 20 large regulatory proteins that circulate in plasma and when activated form a nonspecific defense mechanism against many different microorganisms

neutralization

inactivation of microbes or their toxins through the formation of antigen-antibody complexes

otitis media

infection of the middle ear

phagocytosis

ingestion of solids into cells by means of the formation of vacuoles