Microbiology, 2021

E • Glossary 1207
antibody is first attached to the wells of a
microtiter plate, allowing it to capture
antigen from an unknown solution to be
quantified
Sanger DNA sequencing (dideoxy
method, chain termination method) the
original DNA sequencing technique in
which dideoxy nucleotides, each labeled
with a molecular beacon, are used to
terminate chain elongation; the resulting
incrementally sized fragments are then
separated by electrophoresis to determine
the sequence of the DNA molecule
sanitization protocol that reduces
microbial load on inanimate surfaces to
levels deemed safe for public health
saprozoic refers to protozoans that ingest
small, soluble food molecules
SARS severe acute respiratory syndrome;
caused by a zoonotic coronavirus that
results in flu-like symptoms
saturated fatty acid lipid with
hydrocarbon chains containing only single
bonds, which results in the maximum
number of hydrogen atoms per chain
scanning electron microscope (SEM) a
type of electron microscope that bounces
electrons off of the specimen, forming an
image of the surface
scanning probe microscope a
microscope that uses a probe that travels
across the surface of a specimen at a
constant distance while the current, which
is sensitive to the size of the gap, is
measured
scanning tunneling microscope a
microscope that uses a probe that is
passed just above the specimen as a
constant voltage bias creates the potential
for an electric current between the probe
and the specimen
scarlet fever bacterial infection caused by
Streptococcus pyogenes, marked by a high
fever and a disseminated scarlet rash
schistosomiasis helminthic infection
caused by Schistosoma spp.; transmitted
from a snail intermediate host to human
swimmers or bathers in freshwater
schizogony asexual reproduction in
protozoans that is characterized by
multiple cell divisions (one cell dividing to
form many smaller cells)
scolex the head region of a cestode
(tapeworm), which typically has suckers
and/or hooks for attachment to the host
scrapie form of transmissible spongiform
encephalopathy that primarily affects
sheep
sebaceous gland a gland located in hair
follicles that secretes sebum
sebum lipid-rich substance secreted by
the sebaceous glands of the skin
secondary antibody antibody to which an
enzyme is attached for use in ELISA
assays; in direct and sandwich ELISAs, it is
specific for the antigen being quantified,
whereas in indirect ELISA, it is specific for
the primary antibody
secondary immunodeficiency impaired
immune response due to infection,
metabolic disturbance, poor diet, stress, or
other acquired factors
secondary infection second infection that
develops after a primary infection as a
result of the primary disease
compromising immune defenses or
antibiotics, thus eliminating protective
microbiota
secondary lymphoid tissue one of two
types of lymphatic tissue; comprises the
spleen, lymph nodes, Peyer’s patches, and
mucosa associated lymphoid tissue
(MALT)
secondary response the adaptive
immune response produced in response
to a specific antigen to which the body has
previously been exposed
secondary structure structure stabilized
by hydrogen bonds between the carbonyl
and amine groups of a polypeptide chain;
may be an α-helix or a β-pleated sheet, or
both
secretory vesicle membranous sac that
carries molecules through the plasma
membrane to be released (secreted) from
the cell
selective IgA deficiency primary
immunodeficiency in which individuals
produce normal levels of IgG and IgM, but
are unable to produce secretory IgA
selective media media that contain
additives that encourage the growth of
some bacteria while inhibiting others
selective toxicity desirable quality of an
antimicrobial drug indicating that it
preferentially kills or inhibits the growth
of the target microbe while causing
minimal or no harm to the host
semiconservative DNA replication
pattern of DNA replication process
whereby each of the two parental DNA
strands acts as a template for new DNA to
be synthesized, producing hybrid old- and
new-strand daughter molecules
semicritical item object that contacts
mucous membranes or nonintact skin but
does not penetrate tissues; requires a high
level of disinfection
seminal vesicles glands that contribute
fluid to semen
semisynthetic antimicrobial chemically
modified derivative of a natural antibiotic
sense strand strand of DNA that is not
transcribed for gene expression; it is
complementary to the antisense strand
sepsis systemic inflammatory response to
an infection that results in high fever and
edema, causing organ damage and
possibly leading to shock and death
septate hyphae hyphae that contain walls
between individual cells; characteristic of
some fungi
septic arthritis see infectious arthritis
septic shock serious condition marked by
the loss of blood pressure resulting from
an inflammatory response against a
systemic infection
septic the condition of being septicemic;
having an infection in the blood
septicemia condition in which pathogens
are multiplying in blood
septicemic plague form of plague that
occurs when the bacterial pathogen gains
access to the bloodstream
septum separating structure that forms
during cell division; also describes the
separating wall between cells in a filament
sequela (plural: sequelae) condition that
arises as a consequence of a prior disease
serial dilution sequential transfer of
known volumes of culture samples from
one tube to another to perform a severalfold
dilution of the original culture
seroconversion point in an infection at
which antibody to a pathogen is detectible
using an immunoassay
serotype strain or variation of the same
species of bacteria; also called serovar
serovar specific strain of bacteria