Microbiology, 2021

1212 E • Glossary
trimethoprim synthetic antimicrobial
compound that functions as an
antimetabolite to an enzyme in the
bacterial folic acid synthesis pathway
tRNA small type of stable RNA that carries
the correct amino acid to the site of
protein synthesis in the ribosome and
base pairs with the mRNA to allow the
amino acid it carries to be inserted in the
polypeptide chain being synthesized
trophozoite a life cycle phase in which
protists are actively feeding and growing
tubercle small, rounded lesion
tuberculosis life-threatening form of
microbial infection marked by the
presence of acid-fast bacteria growing in
nodules (especially in the lungs)
tularemia infection of the lymphatic
system by Francisella tularensis; also
known as rabbit fever
tumbles (tumbling) random, circuitous
movement of a bacterial cell, propelled by
clockwise flagellar rotation
tumor collection or aggregate of cells; can
be benign (noncancerous) or malignant
(cancerous)
tumor-inducing (T i ) plasmid a naturally
occurring plasmid of the bacterium
Agrobacterium tumefaciens that
researchers use as a shuttle vector to
introduce a desired DNA fragment into
plant cells
turbidity cloudiness of a culture due to
refraction of light by cells and particles
two-photon microscope a microscope
that uses long-wavelength or infrared light
to fluoresce fluorochromes in the
specimen
tympanic membrane also referred to as
the ear drum, this structure separates the
outer and middle ear
type 1 diabetes mellitus hyperglycemia
caused by an autoimmune disease
affecting insulin production by β cells of
the pancreas
type I hypersensitivity rapid-onset
allergic reaction due to cross-linking of
antigen-specific IgE on the outside of mast
cells, resulting in release of inflammatory
mediators
type II hypersensitivity cytotoxic reaction
triggered by IgG and IgM antibodies
binding to antigens on cell surfaces
type III hypersensitivity inflammatory
reaction induced by formation of immune
complexes and their deposition in tissues
and blood vessels
type IV hypersensitivity delayed T-cellmediated
inflammatory reaction that
takes longer to manifest than the first
three hypersensitivity types, due to the
need for activation of antigen-presenting
cell and T-cell subsets
typhoid fever serious illness caused by
infection with certain serotypes of
Salmonella
U
UHT pasteurization method of
pasteurization that exposes milk to ultrahigh
temperatures (near 140 °C) for a few
seconds, effectively sterilizing it so that it
can be sealed and stored for long periods
without refrigeration
ulcer open sore
ultramicrotome a device that cuts thin
sections for electron microscopy
unit membrane biological membrane
composed of two layers of phospholipid
molecules with the nonpolar tails
associating to form a hydrophobic barrier
between the polar heads; also called lipid
bilayer
unsaturated fatty acid lipid with
hydrocarbon chains containing one or
more carbon-carbon double bonds and
subsequently fewer than the maximum
number of hydrogen atoms per chain
uracil pyrimidine nitrogenous base found
only in RNA nucleotides
ureter duct that transports urine from the
kidneys to the urinary bladder
ureteritis inflammation of the ureter
urethra duct through which urine passes
from the urinary bladder to leave the body
through the urinary meatus
urethritis inflammation of the urethra
urinary bladder an organ that stores
urine until it is ready to be excreted
urinary meatus the opening through
which urine leaves the body
use-dilution test a technique for
determining the effectiveness of a
chemical disinfectant on a surface;
involves dipping a surface in a culture of
the targeted microorganism, disinfecting
the surface, and then transferring the
surface to a fresh medium to see if
bacteria will grow
uterus female reproductive organ in
which a fertilized egg implants and
develops
V
vaccination inoculation of a patient with
attenuated pathogens or antigens to
activate adaptive immunity and protect
against infection
vagina female reproductive organ that
extends from the vulva to the cervix
vaginitis inflammation of the vagina
vaginosis an infection of the vagina
caused by overgrowth of resident bacteria
vancomycin cell wall synthesis inhibitor
of the glycopeptide class
vancomycin-intermediate
Staphylococcus aureus (VISA) pathogen
with intermediate vancomycin resistance
due to increased targets for and trapping
of vancomycin in the outer cell wall
vancomycin-resistant enterococci (VRE)
pathogens resistant to vancomycin
through a target modification of
peptidoglycan subunit peptides that
inhibit binding by vancomycin
vancomycin-resistant Staphylococcus
aureus (VRSA) pathogen with resistance
to vancomycin that has arisen as a result
of the horizontal gene transfer of
vancomycin resistance genes from VRE
variolation the historical practice of
inoculating a healthy patient with
infectious material from a person infected
with smallpox in order to promote
immunity to the disease
vas deferens pair of ducts in the male
reproductive system that conduct sperm
from the testes and seminal fluid to the
ejaculatory duct
vasculitis inflammation affecting blood
vessels (either arteries or veins)
VDRL (Venereal Disease Research
Laboratory) test test for syphilis that
detects anti-treponemal antibodies to the
phospholipids produced due to the tissue
destruction by Treponema pallidum;
antibodies are detected through a
flocculation reaction with cardiolipin
extracted from beef heart tissue
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