Micro Quiz 3

symbiosis

symbiosis

a physical association of two or more different species of organisms

ectosymbiont

organism located on surface of another organism

endosymbiont

organism located within another organism

consortium

hosts that have more than 1 symbiont; relationship can be intermittent/cyclic or permanent

mutualism

reciprocal benefit to both partners with some degree of obligation (cannot live separately: dependent)

zooxanthellae

dinoflagellates harbored by marine invertebrates providing organic carbon to hosts

coral has pigments to protect algae from

UV radiation, providing N compounds, phosphates and CO2 to endosymbionts

coral bleaching

caused by temperature increase. results from loss of photosynthetic pigments/zooxanthellae

cooperation

is beneficial to both organisms involving syntrophic relationships (not obligate)

commensalism

one organism benefits and the other is neither harmed or helped—involves modification of environment

nitrification

carried out by two bacteria together: nitrosomonas, nitrobacter

parasitism

one organism gains and the other is harmed

outcome of long term parasitic relationship

genome reduction, parasite loses genomic information

ammensalism

negative impact of one organism on another based on release of a specific compound

microbiome

all the genes of the host and microbiota

superorganisms

host genes become integrated with the symbionts; co-metabolize various substrates

normal microbiota/microflora

microbes regularly found at anatomical site

humans are born ______ any microorganisms

without

bfidobacteria is found

in breast fed babies

adult bodies contain _______ than human cells

10 times more microbial cell

what organ has the largest normal microbiota in human

large intestine

immunity (nonspecific vs specific)

hosts ability to resist infectious disease

nonspecific (innate, natural)

first line of defense, no immunological memory

specific (acquired, adaptive)

resistance to particular foreign agent; has “memory”

normal/commensal microbiota and the host

normal microbiota prevent colonization by pathogens, bacteria produces vitamins beneficial to host

opportunistic pathogens

members of normal microbiota that produce disease under certain circumstances

compromised host

debilitated host with lowered resistance to infection

skin

inhospitable environment for microbes (shedding, acidic, high NaCl, periodic drying)

strong mechanical barrier to microbial invasion

mucous membrane: mouth

biofilm on teeth, transitional

mucous membrane: stomach

unfriendly environment: gastric acid pH 2-3

mucous membrane: small/large intestine

microbes increase getting closer to large; fluids, pH becomes alkaline

mucous membrane: genitourinary tract

urine flushing kills bacteria, normal microbiota

opsonization enhance phagocytosis

microbes are coated by opsonins in preparation or recognition/ingestion by phagocytic cells

cytokines (chemical mediators)

chemical messages between cells; synthesis is inducible from nonspecific stimuli [soluble proteins/glycoproteins act as intercellular mediators)

leukocytes

white blood cells involved in specific and nonspecific immunity

lymphocytes

kill malignant cells and cells infected with pathogens by releasing cytotoxic enzymes

B lymphocytes

bone marrow; circulate in blood; plasma cells produce antibodies

T lymphocytes

thymus; circulate in blood; differentiate into helper and cytotoxic lymphocytes

inflammation

bring all host defense together in response to injury/infection (innate immune defensive reaction)

antigens

self and non self substances that elicit an immune response and react with products

antibody affinity

strength with which antibody binds to its antigen at binding site

haptens

organic molecules that may become antigenic when bound to larger carrier molecules

major histocompatibility complex (MHC)

collection of genes that code for recognition potential of vertebrate

mature T cells are naive until activated by antigen presentation; once activated,

they proliferate into effector cells and memory cells

primary response

lag period: several days after exposure

IgM appears first, IgG

log phase, plateau phase, decline phase

secondary response

B cells have heightened memory response; shorter lag, quick log, high IgG titer, production of antibodies with high affinity

time course of infectious disease

incubation period, prodromal stage, period of illness, convalescence

virulence

degree or intensity of pathogenicity (toxic to host or resist host defense) determined by genes on pathogenicity islands

virulence attachments

pili and fimbriae bind complementary receptor sites on host cell surface

active penetration

occurs through lytic substances which disrupt host cell surface

passive penetration

spread by body fluid/chemicals

exotoxins

soluble, heat labile, proteins. highly immunogenic

endotoxins

heat stable, weakly immunogenic, cause general system effects indirectly

biofilm development

increases virulence, becomes less sensitive to antibiotics, cells more resistant

direct contact is

less virulent

vector borne and ability to survive outside host are

more virulent

sporadic disease

occurs occasionally and at irregular intervals

endemic disease

maintains a steady low frequency at regular interval

hyperendemic disease

gradually increase in occurrence

COVID-19

SARS-CoV-2, enveloped, +ssRNA

shingles

caused by VZV, reactivated chickenpox when host is immunocompromised