Improved compositions and methods for using modified non-retroviral reverse transcriptase to perform 3′ extension of a nucleic acid, employ non-templated deoxynucleotide addition to a single-stranded nucleic acid and/or synthesis of complementary DNA using non-complementary nucleic acids as primer and template (RNA- or DNA-templated DNA polymerase activity.

Improved compositions and methods for using modified non-retroviral reverse transcriptase to perform 3′ extension of a nucleic acid, employ non-templated deoxynucleotide addition to a single-stranded nucleic acid and/or synthesis of complementary DNA using non-complementary nucleic acids as primer and template (RNA- or DNA-templated DNA polymerase activity.

This specification discloses a novel methodology for labelling RNA via enzymatic incorporation of a minimally perturbing fluorescent tricyclic cytosine analogue. This analogue is shown to be 100% incorporated in example transcripts and is fully compatible with both in vitro and in cell transcription. Spectroscopic characterization shows that the incorporation rate of the cytosine analogue is on par with its natural counterpart. Using live cell imaging and flow cytometry, labelled mRNAs are efficiently and correctly translated upon transfection into living cells and cell-free systems. The spectral properties of the modified transcripts and their correct translation product allow for their straightforward and simultaneous visualization. This technology therefore offers a general route to understanding the biological behaviour of RNA of interest, including RNA based drugs. The fluorescent tricyclic cytosine analogue has formula (I):

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This specification discloses a novel methodology for labelling RNA via enzymatic incorporation of a minimally perturbing fluorescent tricyclic cytosine analogue. This analogue is shown to be 100% incorporated in example transcripts and is fully compatible with both in vitro and in cell transcription. Spectroscopic characterization shows that the incorporation rate of the cytosine analogue is on par with its natural counterpart. Using live cell imaging and flow cytometry, labelled mRNAs are efficiently and correctly translated upon transfection into living cells and cell-free systems. The spectral properties of the modified transcripts and their correct translation product allow for their straightforward and simultaneous visualization. This technology therefore offers a general route to understanding the biological behaviour of RNA of interest, including RNA based drugs. The fluorescent tricyclic cytosine analogue has formula (I):

##STR00001##

DNA is sequenced by: (a) combining dsDNA fragments with Y-adapters and hairpin adapters comprising an affinity-label under conditions wherein the adapters ligate to fragments forming a mixture of fragment inserts flanked by two Y-adapters, a Y-adapter and a hairpin adapter, and two hairpin adapters; and (b) sequencing the selected fragment inserts with sequencing primers selecting for the Y-adapters.

DNA is sequenced by: (a) combining dsDNA fragments with Y-adapters and hairpin adapters comprising an affinity-label under conditions wherein the adapters ligate to fragments forming a mixture of fragment inserts flanked by two Y-adapters, a Y-adapter and a hairpin adapter, and two hairpin adapters; and (b) sequencing the selected fragment inserts with sequencing primers selecting for the Y-adapters.

A method for discriminating between live and dead microbes in a sample, by discriminating between transcriptionally-active and inert microbial nucleic acid sequences in the sample. In particular, the method is based on the comparison of levels of nucleotide substitution in a sample cultured in presence of an RNA-labelling agent. Also, a diagnosis method of microbial infections in a subject; and methods of assessing the risk of contamination of a sample, implementing the method for discriminating between live and dead microbes in a sample.

A method for discriminating between live and dead microbes in a sample, by discriminating between transcriptionally-active and inert microbial nucleic acid sequences in the sample. In particular, the method is based on the comparison of levels of nucleotide substitution in a sample cultured in presence of an RNA-labelling agent. Also, a diagnosis method of microbial infections in a subject; and methods of assessing the risk of contamination of a sample, implementing the method for discriminating between live and dead microbes in a sample.

A method of using a sequencing cell includes applying an alternating signal across a nanopore of the sequencing cell. The method further includes acquiring a first set of voltage data during a first portion of a plurality of cycles of the alternating signal. The method further includes determining a shifted set of voltage data from the first set of voltage data, computing difference data values by computing differences between data points of the first set of voltage data and corresponding data points of the shifted set of voltage data, identifying a plurality of noise data points as data points having difference data values that are larger than a first threshold value, and removing the plurality of noise data points from the first set of voltage data.

A method of using a sequencing cell includes applying an alternating signal across a nanopore of the sequencing cell. The method further includes acquiring a first set of voltage data during a first portion of a plurality of cycles of the alternating signal. The method further includes determining a shifted set of voltage data from the first set of voltage data, computing difference data values by computing differences between data points of the first set of voltage data and corresponding data points of the shifted set of voltage data, identifying a plurality of noise data points as data points having difference data values that are larger than a first threshold value, and removing the plurality of noise data points from the first set of voltage data.