Helix (H)27 of 16S ribosomal (r)RNA from Escherichia coli was dubbed the "switch helix" when mutagenesis suggested that two alternative base pair registers may have distinct functional roles in the bacterial ribosome. Although more recent genetic analyses suggest that H27 conformational switching is not required for translation, previous solution studies demonstrated that the isolated E. coli H...

Ribosomal subunit biogenesis in eukaryotes is a complex multistep process. Mrd1 is an essential and conserved small (40S) ribosomal subunit synthesis factor that is required for early cleavages in the 35S pre-ribosomal RNA (rRNA). Yeast Mrd1 contains five RNA-binding domains (RBDs), all of which are necessary for optimal function of the protein. Proteomic data showed that Mrd1 is part of the ea...

The original interpretation of a series of genetic studies suggested that the highly conserved Escherichia coli 16S ribosomal RNA helix 27 (H27) adopts two alternative secondary structure motifs, the 885 and 888 conformations, during each cycle of amino acid incorporation. Recent crystallographic and genetic evidence has called this hypothesis into question. To ask whether a slippery sequence s...

Helix (H)27 from Escherichia coli 16S ribosomal (r)RNA is centrally located within the small (30S) ribosomal subunit, immediately adjacent to the decoding center. Bacterial 30S subunit crystal structures depicting Mg(2+) binding sites resolve two magnesium ions within the vicinity of H27: one in the major groove of the G886-U911 wobble pair, and one within the GCAA tetraloop. Binding of such me...

Thirty-two strains of Escherichia coli belonging to a new O group, O166, were examined. Twenty-one strains had the flagella antigen H27, five had the H15 antigen, five had the H7 antigen, and one was nonmotile. All the H27 strains and the nonmotile strain produced heat-stable enterotoxin but not heat-labile enterotoxin. All the H7 strains produced heat-labile enterotoxin but not heat-stable ent...

Enteroaggregative Escherichia coli (EAEC), which is identifined by a special characteristic “stacked brick” aggregative adherence to cultured human epithelial cells (1), has been associated with acute and persistent diarrhea in children, in food poisoning diarrhea outbreaks and in overseas travelers (2). In Japan, a massive food-borne outbreak of gastrointestinal illness caused by EAEC O untype...

Enteroaggregative Escherichia coli (EAEC) is a newly diarrheagenic agent wherein several predominant serotypes are reported. We studied the association between those serotypes, as clonal indicators, and the trait of enteroaggregative adherence to host cells, tested by polymerase chain reaction. We also evaluated the clinical manifestations of infection in 17 hospitalized children by our most co...

Azotobacter vinelandii stimulated the growth of Agrobacterium tumefaciens H2, H23, H24, H27, and ATCC 15955 on media containing insoluble iron sources. The Azotobacter vinelandii siderophores appeared to promote Agrobacterium tumefaciens growth by solubilizing mineral iron, and the ferrisiderophores so formed then acted as iron sources for Agrobacterium tumefaciens. Agrobactin, the Agrobacteriu...

Nisin is an antimicrobial peptide that commonly used as a food preservative and capable of inhibiting the pathogen Listeria monocytogenes. However, nisin ineffective in controlling L. monocytogenes Queso Fresco (QF). To address challenge, this work, we synthetic biology strategies to create series A derivatives by substituting residues 27, 30, 31 32 with positively charged amino acids (H, K R)....