Chromosomal integration of Tn5253 occurs downstream of a conserved 11-bp sequence of the rbgA gene in Streptococcus pneumoniae and in all the other known hosts of this integrative conjugative element (ICE).

Background: Tn5253, a composite Integrative Conjugative Element (ICE) of Streptococcus pneumoniae carrying tet(M) and cat resistance determinants, was found to (i) integrate at specific 83-bp integration site (attB), (ii) produce circular forms joined by a 84-bp sequence (attTn), and (iii) restore the chromosomal integration site. The purpose of this study is to functionally characterize the attB in S. pneumoniae strains with different genetic backgrounds and in other bacterial species, and to investigate the presence of Tn5253 attB site into bacterial genomes.

Excision and Circularization of Integrative Conjugative Element Tn of .

The integrative conjugative element (ICE) Tn of , conferring resistance to tetracycline and chloramphenicol, was found integrated at a 83-bp specific target site (B) located in the gene of the pneumococcal chromosome. PCR analysis of Tn-carrying strains showed evidence of precise excision of Tn from the pneumococcal chromosome with production of (i) circular forms of the ICE in which the ends were joined by a 84-bp sequence (Tn), and (ii) reconstituted chromosomal B. When integrated into the chromosome, Tn was flanked by L, identical to B, and R, identical to Tn.

Lack of Prenylated Proteins, Autophagy Impairment and Apoptosis in SH-SY5Y Neuronal Cell Model of Mevalonate Kinase Deficiency.

Background/aims: Mevalonate Kinase Deficiency (MKD), is a hereditary disease due to mutations in mevalonate kinase gene (MVK). MKD has heterogeneous clinical phenotypes: the correlation between MVK mutations and MKD clinical phenotype is still to be fully elucidated. Deficiency of prenylated proteins has been hypothesized as possible MKD pathogenic mechanism.

False positive RNA binding activities after Ni-affinity purification from Escherichia coli.

A His-tag is often added by means of recombinant DNA technology to a heterologous protein of interest, which is then over-produced in Escherchia coli and purified by one-step immobilized metal-affinity chromatography (IMAC). Owing to the presence of 24 histidines at the C-termini of the hexameric E. coli RNA chaperone Hfq, the protein co-purifies with His-tagged proteins of interest.

Transcriptional regulation of nitrate assimilation in Pseudomonas aeruginosa occurs via transcriptional antitermination within the nirBD-PA1779-cobA operon.

Bioinformatic approaches employed to analyse intergenic regions of Pseudomonas aeruginosa O1 (PAO1) for small RNAs (sRNAs) revealed a putative RNA gene encoded upstream of the nitrate assimilation operon nirBD-PA1779-cobA. Here, we show that this RNA, termed nitrogen assimilation leader A (NalA), represents the leader RNA of the nirBD-PA1779-cobA operon, and that nalA transcription is σ(54)- and NtrC-dependent. A PAO1 nalA deletion strain and a strain bearing a deletion in ORF PA1785 failed to grow on nitrate.

Small regulatory RNAs in Pseudomonas aeruginosa.

The opportunistic human pathogen Pseudomonas aeruginosa is frequently associated with nosocomial infections, and can be life threatening in immunosuppressed, cancer and cystic fibrosis patients. Virulence in P. aeruginosa is combinatorial, and results from the activation of several genetic programs that regulate motility, attachment to the host epithelium as well as the synthesis of exotoxins.