microbiology
Troubleshooting a lawn of colonies
A lawn on selective agar usually means the antibiotic failed or far too many cells were plated. Separate those causes before you treat the plate as a success.
8 October 2026 · 10 min read
Knowledge centre
Methods a laboratory can check.
Guides, method explainers and sourcing notes for research laboratories. Written by the EVRINTH Editorial Team from published methods, with catalogue links for enquiry rather than stock claims.
All topicsBuffers and laboratory water26Cell culture26Chromatography26Cold chain and sample storage26Cytometry and microscopy26DNA sequencing26Gels and blotting26Gene expression26Genome editing26Immunoassays26Laboratory labware26Laboratory safety26Liquid handling26Microbiology26Molecular cloning26Nucleic acid purification26PCR and amplification26Protein biochemistry26Proteomics26Research sourcing and study design26
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520 articles
pcr amplification
Troubleshooting a PCR with no band
Define dropout, inhibition, mis-priming, dead enzyme, and missed activation while you investigate an endpoint PCR that produced no band.
8 October 2026 · 7 min read
protein biochemistry
Troubleshooting a smeared protein gel
How to branch a smeared protein gel: overload, salt, DNA, degradation, polymerisation, buffer, bubbles, detergent and a leaking well.
8 October 2026 · 7 min read
cold chain
Troubleshooting a thawed freezer box
Ice and a label tell you only part of a warm box. Quarantine first, then use the product document and the assay control.
8 October 2026 · 10 min read
buffers and water
Troubleshooting an assay that worked last month
Choose the first variable to test when an assay that worked last month now fails: water, pH at the temperature of use, the salt hydrate, the electrode, or the enzyme lot.
8 October 2026 · 9 min read
gene expression
Troubleshooting flat amplification curves
How to read a flat qPCR trace: empty wells, dead reverse transcriptase, inhibition, seal failure and the wrong channel are different failures.
8 October 2026 · 9 min read
molecular cloning
Troubleshooting lawns and satellites
Tell a lawn from ampicillin satellites, decide whether selection failed, and stop before you pick a colony that is only living in a cleared zone.
8 October 2026 · 8 min read
genome editing
Troubleshooting no cutting on a surveyor assay
A Surveyor or T7E1 gel with no cut can mean identical alleles, a skipped anneal, a dead enzyme, a failed PCR, no real cut, or bands the gel cannot separate.
8 October 2026 · 7 min read
immunoassays
Troubleshooting no signal
A flat research ELISA is a broken chain, from coating to wavelength. Separate a truly blank plate from a signal that merely sits below the curve.
8 October 2026 · 11 min read
microbiology
Troubleshooting no transformants
How to read an empty antibiotic plate after transforming non-pathogenic E. coli, using a control plasmid to split cells from DNA.
8 October 2026 · 7 min read
molecular cloning
Troubleshooting plates with no colonies
An empty plate is a place to define competent cells, ligation, selection, and transformation efficiency, then test the failure that actually fits.
8 October 2026 · 7 min read
chromatography
Troubleshooting rising backpressure
Read a rising backpressure trace: frit, precipitate, growth, a collapsed bed, or blocked tubing, and stop before the rated pressure.
8 October 2026 · 7 min read