Deep sequencing reveals as-yet-undiscovered small RNAs in Escherichia coli

<p>Abstract</p> <p>Background</p> <p>In <it>Escherichia coli</it>, approximately 100 regulatory small RNAs (sRNAs) have been identified experimentally and many more have been predicted by various methods. To provide a comprehensive overview of sRNAs, we analysed the low-molecular-weight RNAs (< 200 nt) of <it>E. coli </it>with deep sequencing, because the regulatory RNAs in bacteria are usually 50-200 nt in length.</p> <p>Results</p> <p>We discovered 229 novel candidate sRNAs (≥ 50 nt) with computational or experimental evidence of transcription initiation. Among them, the expression of seven intergenic sRNAs and three <it>cis</it>-antisense sRNAs was detected by northern blot analysis. Interestingly, five novel sRNAs are expressed from prophage regions and we note that these sRNAs have several specific characteristics. Furthermore, we conducted an evolutionary conservation analysis of the candidate sRNAs and summarised the data among closely related bacterial strains.</p> <p>Conclusions</p> <p>This comprehensive screen for <it>E. coli </it>sRNAs using a deep sequencing approach has shown that many as-yet-undiscovered sRNAs are potentially encoded in the <it>E. coli </it>genome. We constructed the <it>Escherichia coli </it>Small RNA Browser (ECSBrowser; <url>http://rna.iab.keio.ac.jp/</url>), which integrates the data for previously identified sRNAs and the novel sRNAs found in this study.</p

Exploring Links Between Aural Lexical Knowledge and L2 Listening in Arabic and Japanese Speakers: A Close Replication of Cheng, Matthews, Lange and McLean (2022)

Aural lexical knowledge (ALK) is crucial for second language (L2) listening. Despite its importance, there is scant research that has validly explored the relationship between ALK and L2 listening across different English as a Foreign Language (EFL) contexts. In an effort to broaden this research base, the current study closely replicates a previous study, Cheng et al. (2022), which measured single-word ALK, phrasal verb ALK and L2 listening comprehension among participants with Chinese as a first language (L1). The current study administered the same instruments but did so among 147 Japanese and 131 Arabic-speaking English language learners. Results indicated that the capacity of ALK to predict variance in L2 listening for the Japanese group (R2 = .38) was similar to that observed in the original study (R2 = .42). However, the results for the Arabic-speaking group were very different to that of the original study and showed an unexpectedly strong relationship between ALK and L2 listening (R2 = .92). Future research directions and pedagogical implications are discussed