Characterization of Individual Polynucleotide Molecules Using a Membrane Channel
Proceedings of the National Academy of Sciences, 1996 · paper · Instrumentation
Shows that an electric field can drive single-stranded RNA and DNA through a 2.6-nm membrane channel, each molecule briefly reducing ionic current. Blockade duration is proportional to polymer length, so it can measure length and might eventually read sequence.
Checked: PDF from europepmc.org, fetched 4 Oct 2026. Page numbers are those of that PDF.
2 findings
Substance Methods say blockades were estimated "in the experiment with 40 channels", but Table 1 lists the multichannel experiments as 35, 8 and 6 channels and has no 40-channel row.
- p. 2 Materials and Methods, PCR Analysis and Blockade Counts
experiment with 40 channels, the number of blockades was
- p. 3 Table 1, first row, No. of channels
35
- p. 2 Methods, PCR Analysis and Blockade Counts
in the experiment with 40 channels
- p. 2 Methods, PCR Analysis and Blockade Counts
in the experiment with 40 channels, the number of blockades was
Only the authors can say what is right here.
Judge's note: Page 2 Methods (crop C002-a): blockades were counted directly "In experiments with 1–8 channels" and estimated by multiplication "in the experiment with 40 channels". The page 3 image shows Table 1 with rows of 35, 8 and 6 channels (1300, 220 and 150 blockades/min). The 8- and 6-channel rows belong to the 1–8 group, so the only experiment that would need an estimate is the 35-channel one. The 40-channel experiment is not mentioned anywhere else in the text (grep). The channel count is a direct multiplier in the estimate. Only the authors can say whether 35 or 40 is correct.
Second check: another model agreed
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Reference or label First affiliation reads "Biotechnology Division, National Institute of Science and Technology, 222/A353, Gaithersburg, MD 20899"; the Gaithersburg institute is the National Institute of Standards and Technology.
- p. 1 Affiliation line, first affiliation (*)
National Institute of Science and Technology
Only the authors can say what is right here.
Judge's note: Rests on outside knowledge: the institute at Gaithersburg, MD 20899 is named the National Institute of Standards and Technology. The page 1 crop shows "National Institute of Science and Technology" exactly as quoted, so this is not an extraction artefact.
Second check: another model agreed
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4 minor (typos and the like; most checked by the judge only)
Wording The Fig. 3 legend gives "poly[U] of mean length 215 nt at the indicated voltages", while Figs. 1 and 2 and the text use poly[U] of mean length 210 nt; the paper does not say whether this is a different fraction.
- p. 3 Fig. 3 legend
poly[U] of mean length 215 nt
- p. 2 Fig. 2 legend / Results text
mean length, 210 nt
- p. 3 Fig. 3 caption
poly[U] of mean length 215 nt at the indicated voltages
- p. 2 Fig. 1 caption
poly[U] of mean length 210 bases
Judge's note: Images checked: the Fig. 1 legend reads "mean length 210 bases", the Fig. 2 legend reads "mean length, 210 nt", the text reads "210-nt-long poly[U]", and the Fig. 3 legend reads "215 nt". The text says Fig. 3 draws on "other size selected poly[U]s", and Fig. 3a uses 13 fractions. So the 215-nt sample may be a separate preparation. In addition, the peak 3 lifetime in Fig. 3b near -120 mV (about 1100 µs) does not obviously match the peak 3 position in Fig. 2 (about 1300 µs). Either reading could be legitimate, so this is recorded as an observation about unclear wording.
Second check: another model agreed
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Typo Reference 22 (Lee & Obukhov) is cited only once, at the end of the Discussion ("and through multiple pores (22) could easily be tested"), after references 23-28; all other references are numbered in order of first citation.
- p. 3 Results and Discussion, last paragraph on the page
and through multiple pores (22) could easily be tested
- p. 1 Materials and Methods, Conductance Measurements
(ref. 23,
- p. 1 Materials and Methods, Conductance Measurements
(ref. 23, patterned after ref. 21)
Judge's note: I traced the citations through the text and page images. References 1-21 appear in order in the introduction, then 'ref. 23, patterned after ref. 21', then 24, 25, 26, 27, 28, and last 22. No earlier citation of 22 exists. Reference 22 fits the sentence that cites it, so this is a numbering-order blemish and not a wrong citation.
Second check: none (judge only)
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Typo Fig. 3b x-axis is labelled "1/Applied Potential (Volts)" with ticks -8, -10, -12; the plotted reciprocal potential has units of V^-1, not volts.
- p. 3 Fig. 3b x-axis
1/Applied Potential (Volts)
Judge's note: Label and ticks read on the page 3 image. 1/(-0.120 V) is -8.33 V^-1, which matches the first data point, so the axis values are reciprocal volts. The label can be read as '1/(potential in volts)', so the meaning is recoverable and the defect is cosmetic. The same point was raised within C004 and is judged here.
Second check: none (judge only)
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Typo The same co-author is spelled two ways in consecutive references: ref. 19 "Bustamante, J. O., Hanover, J. A. & Leipins, A. (1995)" and ref. 20 "Hanover, J. A. & Liepins, A."
- p. 4 Reference 19
Bustamante, J. O., Hanover, J. A. & Leipins, A. (1995)
- p. 4 Reference 20
Hanover, J. A. & Liepins, A.
- p. 4
Bustamante, J. O., Hanover, J. A. & Leipins, A.
- p. 4 Ref. 19
Hanover, J. A. & Leipins, A. (1995)
Only the authors can say what is right here.
Judge's note: Both spellings are visible on the page 4 image. The two entries are back-to-back papers in J. Membr. Biol. 146 (239-251 and 253-261) with overlapping authors, so one spelling is a misprint. The inconsistency is internal to the paper. Which spelling is correct (probably 'Liepins') rests on outside knowledge and cannot be settled from the files.
Second check: another model agreed