GLOSSARY - Bioaugmentation for Groundwater Remediation - page 375

Terminal restriction fragment length polymorphism (T-RFLP) ‐ A molecular biology
technique used to profile microbial communities based on the position of a restriction site
closest to a labeled end of an amplified gene. The method is based on digesting a mixture of
PCR amplified variants of a single gene using one or more restriction enzymes and detecting
the size of each of the individual resulting terminal fragments using a DNA sequencer.

Thermodynamic ‐ The study of the conversion of energy into work and heat and its relation
to macroscopic variables, such as temperature and pressure.

Total dissolved solids (TDS) ‐ Combined content of all inorganic and organic substances in a
liquid that are present in a molecular, ionized, or micro-granular (colloidal sol) suspended form.

Total organic carbon (TOC) ‐ Mass of carbon bound in organic compounds in soils,
sediments, and water. Often used as a nonspecific indicator of water quality.

Toxicity ‐ The degree to which a substance or mixture of substances can cause harm to
organisms. Acute toxicity involves harmful effects in an organism through a single or short-
term exposure. Chronic toxicity is the ability of a substance or mixture of substances to cause
harmful effects over an extended period.

Transcription ‐ The process of creating a complementary RNA copy (a transcript) of a DNA
sequence. During transcription, a DNA sequence is read by an enzyme (RNA polymerase) that
produces a complementary RNA strand. Transcription is thus the first step in gene expression,
and is followed by translation of the RNA into proteins or other gene products.

Transcriptomics ‐ The study of the transcriptome (all of the RNA molecules in a cell or
population of cells). Transcriptomics thus allows the study of the genes that are being actively
expressed at any given time, not just the genes that are present (i.e., genomics).

Transduction ‐ Use of a bacteriophage (bacterial virus) to transfer genetic material between
organisms.

Transformation ‐ 1. DNA transfer through direct bacterial incorporation of extracellular
DNA. 2. Abiotic or biotic catalyzed change of a chemical to some other product.

Translation ‐ The decoding of messenger RNA to produce specific polypeptides. Occurs
after transcription.

Transposon ‐ A DNA sequence that can self-transpose (i.e., it can independently replicate
itself and insert the copy into a new position within the same or another chromosome or
plasmid). These so-called “jumping genes” (also known as transposable elements) are one form
of “mobile genetic elements.” Transposition has been useful to researchers as a method to alter
the DNA within living organisms.

Trichloroethane (TCA) ‐ An industrial solvent (CH 3 CCl 3 ). Other names for it include methyl
chloroform and chloroethane. Occurs in two isomers: 1,1,1-TCA and 1,1,2-TCA

Trichloroethene (TCE) CCl 2 ). Used as

a solvent or metal degreasing agent and in other industrial applications. Toxic if inhaled, and a
suspected carcinogen. Also called trichloroethylene.

‐ A stable, low-boiling-point, colorless liquid (CHCl ¼