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

Amplification plots of BurkDiff.

<p>Quadruplicates of 10-fold serial dilutions of DNA from a crude heat lysis extraction of A. <i>B. mallei</i> strain 2002734303 and B. <i>B. pseudomallei</i> strain 2002721637 were screened on BurkDiff to determine the limit of detection of the assay. Two of 4 replicates at the 10¹ copies template amount did not amplify for both species.</p

Number and origin of <i>B. pseudomallei</i>, <i>B. mallei</i>, and genetic near-neighbor strains used in this study.

<p>Number and origin of <i>B. pseudomallei</i>, <i>B. mallei</i>, and genetic near-neighbor strains used in this study.</p

BurkDiff allelic discrimination plot.

<p>Results from the assay across 45 <i>B. pseudomallei</i> and 23 <i>B. mallei</i> strains are shown, along with 2 no template controls (NTCs) and 26 near-neighbor and differential diagnostic species.</p

Species and number of differential diagnostic and background flora strains screened across BurkDiff to validate the assay's specificity.

<p>Out of the 328 strains from approximately 80 species, none amplified.</p

VNTR markers.

<p>*Data obtained in this study.</p>†<p>The individual marker diversity (D) was calculated as D = [1-∑(allele frequency)²].</p>††<p>Location within an open reading frame.</p><p>VNTR markers.</p

<i>PmeI</i> pulsed-field gel electrophoresis (PFGE) patterns for <i>F. tularensis</i> subsp. <i>holarectica</i>.

<p>Polymorphic band position 1 consists of two fragments in PFGE type 2. Polymorphic band position 2 and 3 consist of two fragments at the same position, both missing in PFGE type 2. Polymorphic band position 6 consists of two fragments in PFGE type 3.</p

TaqMan Real-Time PCR Assays for Single-Nucleotide Polymorphisms Which Identify <i>Francisella tularensis</i> and Its Subspecies and Subpopulations

<div><p><i>Francisella tularensis</i>, the etiologic agent of tularemia and a Class A Select Agent, is divided into three subspecies and multiple subpopulations that differ in virulence and geographic distribution. Given these differences, there is a need to rapidly and accurately determine if a strain is <i>F. tularensis</i> and, if it is, assign it to subspecies and subpopulation. We designed TaqMan real-time PCR genotyping assays using eleven single nucleotide polymorphisms (SNPs) that were potentially specific to closely related groups within the genus <i>Francisella</i>, including numerous subpopulations within <i>F. tularensis</i> species. We performed extensive validation studies to test the specificity of these SNPs to particular populations by screening the assays across a set of 565 genetically and geographically diverse <i>F. tularensis</i> isolates and an additional 21 genetic near-neighbor (outgroup) isolates. All eleven assays correctly determined the genetic groups of all 565 <i>F. tularensis</i> isolates. One assay differentiates <i>F. tularensis</i>, <i>F. novicida</i>, and <i>F. hispaniensis</i> from the more genetically distant <i>F. philomiragia</i> and <i>Francisella-</i>like endosymbionts. Another assay differentiates <i>F. tularensis</i> isolates from near neighbors. The remaining nine assays classify <i>F. tularensis</i>-confirmed isolates into <i>F. tularensis</i> subspecies and subpopulations. The genotyping accuracy of these nine assays diminished when tested on outgroup isolates (i.e. non <i>F. tularensis</i>), therefore a hierarchical approach of assay usage is recommended wherein the <i>F. tularensis</i>-specific assay is used before the nine downstream assays. Among <i>F. tularensis</i> isolates, all eleven assays were highly sensitive, consistently amplifying very low concentrations of DNA. Altogether, these eleven TaqMan real-time PCR assays represent a highly accurate, rapid, and sensitive means of identifying the species, subspecies, and subpopulation of any <i>F. tularensis</i> isolate if used in a step-wise hierarchical scheme. These assays would be very useful in clinical, epidemiological, and/or forensic investigations involving <i>F. tularensis</i>.</p></div

Geographical distribution of isolates from this study.

<p>Circle size represents the number of isolates found at a specific sampling site and the color represents different species as determined by <i>recA</i> or 16s <i>rRNA</i> sequencing. Division of circles indicates that multiple species were found at a site. <i>B</i>. <i>ubonensis</i> is commonly found throughout Darwin and the surrounding areas. Several species were found in the same soil sample as <i>B</i>. <i>pseudomallei</i> including <i>B</i>. <i>ubonensis</i>, several <i>B</i>. <i>cepacia</i> complex species, proposed <i>B</i>. <i>humptydooensis</i>, <i>Pandoraea</i>, and <i>Cupriavidus</i>.</p

Comparison of environmental species identified in the Darwin region of Australia.

<p>(-) indicates that no <i>B</i>. <i>pseudomallei</i> was found to occur with a species or that the molecular assay was negative for that target.</p><p>^a Site refers to the GPS location from which soil or water samples were taken.</p><p>^b<i>B</i>. <i>pseudomallei</i> were recovered from the same soil or water sample as the isolate.</p><p>Comparison of environmental species identified in the Darwin region of Australia.</p