The structural gene for arylsulfatase (atsA) of Klebsiella aerogenes was cloned into a pKI212 vector in Escherichia coli. Deletion analysis showed that the atsA gene with the promoter region was located within a 3.2-kilobase cloned segment. In E. colh cells which carried the plasmid, the synthesis of arylsulfatase was repressed by various sources of sulfur; the repression was relieved, in each case, by tyramine. Transfer of the plasmid into atsA or constitutive atsR mutant strains of K. aerogenes resulted in complementation of atsA but not of atsR. The nucleotide sequence of the 3.2-kilobase fragment was determined. Two open reading frames, the atsA gene and an unknown gene (atsB), were found. These are located between a potential promoter and a transcriptional terminator sequence. Deletion analysis suggests that atsB is a potential positive factor for the regulation of arylsulfatase. Analysis of the amino acid sequences of the first 13 amino acids from the N terminus of the purified secreted arylsulfatase agrees with that of the nucleotide sequence of atsA. The leader peptide extends over 20 amino acids and has the characteristics of a signal sequence. Primer extension mapping of transcripts generated in vivo suggests that the synthesis of mRNA starts at a site 31 or 32 bases upstream from the ATG initiation codon of the atsB gene. By Northern (RNA) blot analysis of the transcripts induced by tyramine, we found a 2.7-kilobase transcript which is identical in size to the total sequence of the atsB and atsA genes. Thus, the ats operon is composed of two cistrons and is regulated by sulfur and tyramine.

The Klebsiella aerogenes gene maoA, which is involved in the synthesis of monoamine oxidase, was induced by tyramine and the related compounds, subjected to catabolite and ammonium ion repression, and cloned. The nucleotide sequence of the region involved in monoamine oxidase synthesis was determined. Two open reading frames, the maoA gene and a hitherto unknown gene (maoC), were found. These are located between a potential promoter sequence and a transcriptional terminator sequence. A region of the Escherichia coli chromosome that was highly homologous to the KiebsieUla maoA gene was found. The potential maoA gene is located at 30.9 min on the E. coli chromosome. Analysis of the amino acid sequences of the first 11 amino acids from the N terminus of the purified monoamine oxidase agrees with those deduced from the nucleotide sequence of the maoA gene. The leader peptide extends over 30 amino acids and has the characteristics of a signal sequence. Primer extension and S1 nuclease mapping of transcripts generated in vivo suggests that the tyramine-induced mRNA starts at a site 62 bases upstream from the ATG initiation codon of the maoC gene.In the putative promoter region, a high degree of similarity to the consensus sequence for the binding site of cyclic AMP receptor protein was found. Thus, the mao region is composed of two cistrons, and the mao operon is regulated by monoamine compounds, glucose, and ammonium ions.

Introduction:The rapid and accurate detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is required to prevent the spread of COVID-19. This study evaluated the utility of two SARS-CoV-2 antigen detection methods. Methods: We evaluated two types of antigen detection methods using immunochromatography (Espline) and quantitative chemiluminescent enzyme immunoassay (Lumipulse). RT-PCR was performed as a standard procedure for COVID-19 diagnosis. Lumipulse and RT-PCR were performed for all 486 nasopharyngeal swabs and 136 saliva samples, and the Espline test was performed for 271 nasopharyngeal swabs and 93 saliva samples. Results: The sensitivity and specificity of the Espline test were 10/11 and 260/260 (100%), respectively for the nasopharyngeal swabs and 3/9 and 84/84 (100%), respectively for the saliva samples. High sensitivities for both saliva (8/9) and nasopharyngeal swabs (22/24) were observed in the Lumipulse test. The specificities of the Lumipulse test for nasopharyngeal swabs and saliva samples were 460/462 (99.6%) and 123/127 (96.9%), respectively. Conclusion: The Espline test is not effective for saliva samples but is useful for simple and rapid COVID-19 tests using nasopharyngeal swabs because it does not require special devices. The Lumipulse test is a powerful high-throughput tool for COVID-19 diagnosis because it has high detection performance for nasopharyngeal swabs and saliva samples.

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