Microbiology, 2021

E • Glossary 1199
target cells by inducing apoptosis
natural passive immunity transfer of
maternal antibodies from mother to fetus
(transplacentally) or infant (via
breastmilk)
necrotizing fasciitis a serious infection,
also known as flesh-eating disease, that
leads to rapid destruction of tissue
through the action of exotoxin A; it can be
caused by S. pyogenes or several other
bacterial species
negative (–) single-strand RNA (–ssRNA)
a viral RNA strand that cannot be
translated until it is replicated into
positive single-strand RNA by viral RNAdependent
RNA polymerase
negative stain a stain that produces color
around the structure of interest while not
coloring the structure itself
Nematoda phylum comprising
roundworms
neonatal herpes herpes infection of the
newborn, generally caused by infection
during birth
neonatal meningitis meningitis caused by
Group B streptococcus and occurring
primarily in neonates (less than 2 months
old)
neonatal tetanus tetanus acquired
through infection of the cut umbilical cord
neurocysticercosis parasitic invasion of
brain tissues by the larvae of the pork
tapeworm, Taenia solium
neuromycosis any fungal infection of the
nervous system
neuron specialized cell found throughout
the nervous system that transmits signals
through the nervous system using
electrochemical processes
neuropathy numbness or tingling
sensation caused by damage to peripheral
nerves
neurotoxoplasmosis disease caused by
the invasion of brain tissues by the
protozoan Toxoplasma gondii; typically
only affects immunocompromised
patients
neurotransmitter compound that is
released at the synapse of neurons to
stimulate or suppress the actions of other
cells
neutralism type of symbiosis that does
not affect either of the two populations
neutralization binding of an antibody to a
pathogen or toxin, preventing attachment
to target cells
neutrophile organism that grows best at a
near a neutral pH of 6.5–7.5
neutrophils leukocytes with a multilobed
nucleus found in large numbers in
peripheral blood; able to leave the
bloodstream to phagocytose pathogens in
infected tissues; also called
polymorphonuclear neutrophils (PMNs)
next generation sequencing a group of
automated techniques used for rapid DNA
sequencing
nicotine adenine dinucleotide
(NAD + /NADH) oxidized/reduced forms of
an electron carrier in cells
nicotine adenine dinucleotide phosphate
(NADP + /NADPH) oxidized/reduced forms
of an electron carrier in cells
nitrogen fixation bacterial biochemical
pathways that incorporate inorganic
nitrogen gas into organic forms more
easily used by other organisms
nitrogenous base nitrogen-containing
ring structure within a nucleotide that is
responsible for complementary base
pairing between nucleic acid strands
noncoding DNA regions of an organism’s
genome that, unlike genes, do not encode
proteins
noncommunicable disease disease that is
not transmitted from one person to
another
noncompetitive (allosteric) inhibitor
molecule that binds to allosteric sites,
inducing a conformational change in the
enzyme’s structure that prevents it from
functioning
noncritical item object that may contact
intact skin but does not penetrate it;
requires cleanliness but not a high level of
disinfection
noncyclic photophosphorylation
pathway used in photosynthetic
organisms when both ATP and NADPH are
required by the cell
nonenveloped virus naked virus
nongonococcal urethritis (NGU) a
nonspecific infection of the urethra that is
not caused by Neisseria gonorrhoeae
noninfectious disease disease caused by
something other than an infectious agent
(e.g., genetics, environment, nutritional
deficiencies)
nonionizing radiation low-energy
radiation, like ultraviolet light, that can
induce dimer formation between two
adjacent pyrimidine bases, resulting in
DNA polymerase stalling and possible
formation of a frameshift mutation
nonsense mutation point mutation that
converts a codon encoding an amino acid
(a sense codon) into a stop codon (a
nonsense codon)
nontreponemal serologic tests
qualitative and quantitative indirect
diagnostic tests for syphilis
northern blot a technique in molecular
genetics used to detect the amount of RNA
made by gene expression within a tissue
or organism sample; RNA fragments
within a sample are separated by agarose
gel electrophoresis, immobilized on a
membrane, and then exposed to a specific
DNA probe labeled with a radioactive or
fluorescent molecular beacon to aid in
detection
nosocomial disease disease acquired in a
hospital setting
notifiable disease a disease for which all
cases must legally be reported to regional,
state, and/or federal public health
agencies
nuclear envelope (also called the nuclear
membrane) a structure defining the
boundary of the nucleus; composed of two
distinct lipid bilayers that are contiguous
with each other and with the endoplasmic
reticulum
nuclear lamina a meshwork of
intermediate filaments (mainly lamins)
found just inside the nuclear envelope;
provides structural support to the nucleus
nucleic acid class of macromolecules
composed of nucleotide monomers
polymerized into strands
nucleoid concentrated area of DNA
genome and associated proteins found in a
prokaryotic cell that is not surrounded by
a membrane
nucleoid-associated protein (NAP)
protein that assists in the organization and
packaging of the chromosome in
prokaryotic cells
nucleolus a dense region within the