Loop-Mediated Isothermal Amplification (LAMP) – Key Vocabulary

Vocabulary flashcards covering core terms, components, mechanisms, and comparative advantages of the LAMP technique presented in the lecture notes.

Loop-Mediated Isothermal Amplification (LAMP)

A DNA amplification method that rapidly produces up to 10^9 copies of a target sequence under constant temperature (≈60–65 °C) using strand displacement synthesis and four specialized primers.

Isothermal Amplification

DNA or RNA amplification carried out at a single incubation temperature, eliminating the need for thermal cycling.

Strand Displacement DNA Synthesis

Polymerase-mediated extension that displaces downstream DNA strands, key to LAMP’s continuous amplification without heat denaturation.

Forward Inner Primer (FIP)

One of two inner primers in LAMP; contains F1c sequence, a TTTT spacer, and F2 complementary sequence to initiate synthesis and later self-prime via loop formation.

Backward Inner Primer (BIP)

Inner primer pairing to the opposite end of the target; carries B1c sequence, a TTTT spacer, and B2 sequence for synthesis and self-priming.

Outer Primers (F3 & B3)

Shorter, lower-concentration primers that initiate initial strand displacement; not used during later cycling of LAMP.

F1c / B1 (Loop Sequences)

Regions ~40 nt inside the target ends that form the single-stranded loops necessary for stem-loop DNA structures in LAMP.

F2 / B2 (Core Target Sequences)

23–24 nt regions where inner primers anneal first to begin complementary strand synthesis.

Six-Site Recognition

Initial LAMP step in which four primers bind six distinct regions on the target, providing very high specificity.

Stem-Loop DNA

Key intermediate/product in LAMP formed when complementary ends of a displaced strand anneal, creating a loop that serves as a primer site.

Dumb-Bell DNA Structure

Closed circular intermediate with loops at both ends generated early in LAMP, rapidly converted to stem-loop DNA.

Cauliflower-Like DNA

Final LAMP products containing multiple inverted repeats and loops, giving a branched, high-molecular-weight structure.

Bst DNA Polymerase (Large Fragment)

Strand-displacing enzyme from Bacillus stearothermophilus used in LAMP for efficient, high-temperature (65 °C) synthesis.

Betaine

Helix-destabilizing agent (0.5–1.5 M) that accelerates LAMP and suppresses nonspecific amplification.

Reaction Temperature (60–65 °C)

Optimal range for Bst polymerase activity and primer Tm values, enabling efficient isothermal amplification in LAMP.

Primer Concentration Ratio

Inner primers used at 0.8 µM each, outer primers at ~¼–¹⁄₁₀ that amount to favor inner-primer initiation.

Target Size (130–200 bp)

Recommended amplicon length for maximal LAMP efficiency; fragments >500 bp amplify poorly.

Sensitivity of LAMP

Ability to detect as few as 6 copies of target DNA in <1 hour, comparable to or exceeding PCR.

Specificity of LAMP

High selectivity achieved by six initial and four subsequent target-recognition sites, reducing background amplification.

Reverse Transcription-LAMP (RT-LAMP)

Adaptation combining reverse transcriptase with LAMP to amplify RNA targets such as PSA mRNA.

M13mp18 DNA

Bacteriophage plasmid used as a model target to demonstrate LAMP mechanism and product analysis.

Hepatitis B Virus (HBV) DNA

Clinical target amplified in sensitivity tests; six HBV copies detectable by LAMP despite excess human genomic DNA.

Prostate-Specific Antigen (PSA) mRNA

Example RNA target detected by RT-LAMP from a single PSA-expressing cell among one million negatives.

Nested PCR

Two-round PCR method improving specificity; contrasted with LAMP, which achieves high specificity without thermal cycling.

Strand Displacement Amplification (SDA)

Older isothermal method using modified nucleotides and restriction enzymes; LAMP avoids these extra requirements.