Preparation and characterization of antibacterial cobalt-exchanged natural zeolite/poly(vinyl alcohol) hydrogels

In the present study, potential application of the local clinoptilolite-rich natural zeolite in formulation of antibacterial hydrogels was investigated. The zeolite powder exchanged with cobalt(II) ions was used in preparation of the zeolite/poly(vinyl alcohol) hydrogel films in different amounts. The films were physically crosslinked by the freezing-thawing method and characterized for their crystallinity, surface and cross sectional morphology, chemical composition, thermal behaviour, mechanical properties, swelling and dissolution behaviours, and antibacterial activities against a Gram-negative bacteria. The films with 0.48 wt% and higher cobalt-exchanged zeolite contents showed antibacterial activity. Addition of the zeolite powder in the formulations did not cause significant changes in the other properties of the films.Turkish Republic Prime Ministry State Planning Organization (DPT-2006 K120690

Variant Site Strain Typer (VaST): Efficient strain typing using a minimal number of variant genomic sites

This repository contains the matrices used to build the minimum spanning sets for <i>Yersenia pestis, Bacillus anthracis, </i><i>Escherichia</i><i> coli, Burkholderia pseudomallei, and Francisella tularensis. </i>The target sites identified for resolving each strain complex is also provided in the haplotype files. The loci used for the truncated, experimentally-validated panel are also listed. <br

Sequenced T (translucent or distinct) variants with a <i>motA</i> mutation listed by type (see Figure 3).

1<p>Percentage of variants out of 18 total.</p>2<p>Reversion of the mutation confirmed by sequence analysis. N/D indicates that analysis was not done for this single variant.</p

Amino acid alignment of MotA.

<p>The <i>motA</i> mutations are predicted to result in non-functional proteins. A missense mutation at base 262 (T1, Type B) resulted in an A to P mutation at amino acid 88; a nonsense mutation at base 612 (T3, Type D) resulted in a premature truncation; a duplication of 49 bp created a direct repeat within <i>motA</i> and led to the replacement of the last 73 residues in the C-terminus with a sequence of 39 new residues that are highlighted (T108, Type C); and a deletion at base 64 resulting in a truncated protein (T158, Type A).</p

Nucleotide alignment of <i>motA</i> and mutated alleles.

<p>The four mutations found within <i>motA</i> have been assigned a type for ease in distinguishing. Type A mutation is a deletion at base 64 (T158). Type B mutation is a missense mutation at base 262 (T1). Type C mutation is a duplication of 49 bp (boxed) creating a direct repeat (T108). Type D mutation is a nonsense mutation at base 612 (T3).</p

High Frequency, Spontaneous <i>motA</i> Mutations in <i>Campylobacter jejuni</i> Strain 81-176

<div><p><i>Campylobacter jejuni</i> is an important cause of bacterial diarrhea worldwide. The pathogenesis of <i>C. jejuni</i> is poorly understood and complicated by phase variation of multiple surface structures including lipooligosaccharide, capsule, and flagellum. When <i>C. jejuni</i> strain 81-176 was plated on blood agar for single colonies, the presence of translucent, non-motile colonial variants was noted among the majority of opaque, motile colonies. High-throughput genomic sequencing of two flagellated translucent and two opaque variants as well as the parent strain revealed multiple genetic changes compared to the published genome. However, the only mutated open reading frame common between the two translucent variants and absent from the opaque variants and the parent was <i>motA</i>, encoding a flagellar motor protein. A total of 18 spontaneous <i>motA</i> mutations were found that mapped to four distinct sites in the gene, with only one class of mutation present in a phase variable region. This study exemplifies the mutative/adaptive properties of <i>C. jejuni</i> and demonstrates additional variability in <i>C. jejuni</i> beyond phase variation.</p></div

Derivation of 81-176/55 and the appearance of colonial variants linked with motility.

<p>(A) Cartoon depicting the origin of the sequenced strains. Abbreviations include O for opaque and T for translucent. (B) Appearance of colonial variants of <i>C. jejuni</i> 81-176 grown on CBA plates in microaerobic conditions following dilution and plating. Colony morphology was examined on CBA (C) as well as MH agar (D) and motility analysis made use of 0.6% BB agar 24-well plates with single colonies stabbed into the wells. (E) Transmission electron microscopy images of negatively stained WT, opaque, and translucent variants of <i>C. jejuni</i> strain 81-176.</p

Schematic illustration of the 69-176/55 and its 4 additional sequenced offspring.

<p>The assembly of the whole genome sequences revealed varying SNPs throughout the chromosome. One confirmed difference between the previously sequenced 81-176 and 81-176/55 (as well as the opaque and translucent progeny) was the presence of a 69 bp deletion in the intergenic region between <i>hup</i> and <i>cysK</i>. An incomplete direct repeat (IDR) bracketing the deletion is indicated.</p

Epidemiological data on the 74 <b><i>Acinetobacter baumannii</i></b> isolates included in this study.

<p>^a ST, Sequence type; CST, CRISPR-based sequence type; PFGE, Pulsed-field gel electrophoresis; UAE, United Arab Emirates; WRAMC, Walter Reed Army Medical Center; USA, United States of America; ICU, Intensive care unit.</p><p>Epidemiological data on the 74 <b><i>Acinetobacter baumannii</i></b> isolates included in this study.</p

Schematic comparison of the trailer end of the arrays of spacers in <i>Acinetobacter baumannii</i> AYE and <i>A</i>. <i>baumannii</i> ab299505.

<p>The region carrying spacers Ab-1 to Ab-4 in <i>A</i>. <i>baumannii</i> AYE was missing in <i>A</i>. <i>baumannii</i> ab299505, most likely due to an internal deletion caused by a recombination event between the two direct repeats (highlighted by a black frame) surrounding the deleted region. This created a unique direct repeat (highlighted by a black frame and vertical lines) characterized by a novel mosaic sequence derived from the recombined direct repeats. Sequence of the direct repeats involved in the recombination was presented in adjacent black boxes.</p