Effects of subtherapeutic concentrations of antimicrobials on gene acquisition events in Yersinia, Proteus, Shigella, and Salmonella recipient organisms in isolated ligated intestinal loops of swine

Objective—To assess antimicrobial resistance and transfer of virulence genes facilitated by subtherapeutic concentrations of antimicrobials in swine intestines. Animals—20 anesthetized pigs experimentally inoculated with donor and recipient bacteria. Procedures—4 recipient pathogenic bacteria (Salmonella enterica serotype Typhimurium, Yersinia enterocolitica, Shigella flexneri, or Proteus mirabilis) were incubated with donor bacteria in the presence of subinhibitory concentrations of 1 of 16 antimicrobials in isolated ligated intestinal loops in swine. Donor Escherichia coli contained transferrable antimicrobial resistance or virulence genes. After coincubations, intestinal contents were removed and assessed for pathogens that acquired new antimicrobial resistance or virulence genes following exposure to the subtherapeutic concentrations of antimicrobials. Results—3 antimicrobials (apramycin, lincomycin, and neomycin) enhanced transfer of an antimicrobial resistance plasmid from commensal E coli organisms to Yersinia and Proteus organisms, whereas 7 antimicrobials (florfenicol, hygromycin, penicillin G, roxarsone, sulfamethazine, tetracycline, and tylosin) exacerbated transfer of an integron (Salmonella genomic island 1) from Salmonella organisms to Yersinia organisms. Sulfamethazine induced the transfer of Salmonella pathogenicity island 1 from pathogenic to nonpathogenic Salmonella organisms. Six antimicrobials (bacitracin, carbadox, erythromycin, sulfathiazole, tiamulin, and virginiamycin) did not mediate any transfer events. Sulfamethazine was the only antimicrobial implicated in 2 types of transfer events. Conclusions and Clinical Relevance—10 of 16 antimicrobials at subinhibitory or subtherapeutic concentrations augmented specific antimicrobial resistance or transfer of virulence genes into pathogenic bacteria in isolated intestinal loops in swine. Use of subtherapeutic antimicrobials in animal feed may be associated with unwanted collateral effects

BLM Planning and Implementation: Successes, Challenges and Opportunities

This presentation discusses/illustrates the USDI Bureau of Land Management (BLM) multiple use issue analysis and resolution at two different scales: the Resource Management Plan (RMP) policy scale and the applied project scale. BLM RMPs will be discussed with specific examples of how RMPs guide future management decisions. Greater sage grouse (Centrocercus urophasianus) will be used as a primary example. Seven RMPs in the Montana/Dakotas had drafts for RMP revisions or Greater sage grouse RMP amendments in 2013. Guidance contained in the RMP establishes sideboards for project alternatives and what may be considered. The Crooked Creek Project in the Lewistown Field Office will be covered to illustrate how projects are planned within the framework of an RMP to achieve specific conditions on the ground and the tools, information, and experience used to develop these actions. Finally, examples of applied efforts to improve wildlife habitat across BLM lands in the Montana/Dakotas will be demonstrated

A Report to the Center for Urban and Regional Affairs by Southeast Minneapolis Council on Learning

This report describes work performed by the Southeast Minneapolis Council on Learning (SEMCOL) in the summer of 2008. Its purpose was to examine the idea that outside of schools there are numerous organizations providing learning opportunities, and that it might be useful to study them to discover how extensive these activities are, who has access to them, what the resource base is that supports the increasingly extensive learning taking place outside of schools and what can we do to improve this 'system.' During the course of this grant supported work we contacted more than 40 organizations and interviewed 50 people. We discovered it is not easy to answer fundamental questions about learning outside of schools. Most organizations offering learning either do not formally evaluate themselves, or use varied methods to do so. This makes it even harder to know exactly who the participants are in this 'system', who is paying for what, and how much learning is actually taking place. he other hand we found great enthusiasm for the project. Many people understood the value of trying to come to grips with non-school learning. Specifically, while we are not yet able to answer key underlying questions about the extent and impact of non-school learning, this report did lead to the creation of a new website that will be a one-stop site for all learning in Southeast Minneapolis. The existence of this site will make it possible to begin to gather information that can address key questions. Secondly, this report also led to the creation of another related project - the attempt to reach out to people (especially to those cut off from learning success in the current school system) using video stories of learning. These videos - as we have seen from the first few created - are capable of both inspiring and attracting people to wider community learning opportunities. Both of these positive steps are described in this report, and are the concrete ways that the work described in this report will be continued.Conducted on behalf of SEMCOL. Supported by Neighborhood Partnerships for Community Research (NPCR), a program of the Center for Urban and Regional Affairs (CURA), University of Minnesota

Bredo Johnsen. Righting Epistemology: Hume’s Revolution

Reviewed by Matthew Carlson

Schwinger's Dynamical Casimir Effect: Bulk Energy Contribution

Schwinger's Dynamical Casimir Effect is one of several candidate explanations for sonoluminescence. Recently, several papers have claimed that Schwinger's estimate of the Casimir energy involved is grossly inaccurate. In this letter, we show that these calculations omit the crucial volume term. When the missing term is correctly included one finds full agreement with Schwinger's result for the Dynamical Casimir Effect. We have nothing new to say about sonoluminescence itself except to affirm that the Casimir effect is energetically adequate as a candidate explanation.Comment: 6 pages. Uses LaTeX with RevTeX package in two-column forma

Adverse Effects of Antimicrobials via Predictable or Idiosyncratic Inhibition of Host Mitochondrial Components

This minireview explores mitochondria as a site for antibiotic-host interactions that lead to pathophysiologic responses manifested as nonantibacterial side effects. Mitochondrion-based side effects are possibly related to the notion that these organelles are archaic bacterial ancestors or commandeered remnants that have co-evolved in eukaryotic cells; thus, this minireview focuses on mitochondrial damage that may be analogous to the antibacterial effects of the drugs. Special attention is devoted to aminoglycosides, chloramphenicol, and fluoroquinolones and their respective single side effects related to mitochondrial disturbances. Linezolid/oxazolidinone multisystemic toxicity is also discussed. Aminoglycosides and oxazolidinones are inhibitors of bacterial ribosomes, and some of their side effects appear to be based on direct inhibition of mitochondrial ribosomes. Chloramphenicol and fluoroquinolones target bacterial ribosomes and gyrases/topoisomerases, respectively, both of which are present in mitochondria. However, the side effects of chloramphenicol and the fluoroquinolones appear to be based on idiosyncratic damage to host mitochondria. Nonetheless, it appears that mitochondrion-associated side effects are a potential aspect of antibiotics whose targets are shared by prokaryotes and mitochondria—an important consideration for future drug design

The topomer-sampling model of protein folding

Clearly, a protein cannot sample all of its conformations (e.g., ≈3^(100) ≈ 10^(48) for a 100 residue protein) on an in vivo folding timescale (<1 s). To investigate how the conformational dynamics of a protein can accommodate subsecond folding time scales, we introduce the concept of the native topomer, which is the set of all structures similar to the native structure (obtainable from the native structure through local backbone coordinate transformations that do not disrupt the covalent bonding of the peptide backbone). We have developed a computational procedure for estimating the number of distinct topomers required to span all conformations (compact and semicompact) for a polypeptide of a given length. For 100 residues, we find ≈3 × 10^7 distinct topomers. Based on the distance calculated between different topomers, we estimate that a 100-residue polypeptide diffusively samples one topomer every ≈3 ns. Hence, a 100-residue protein can find its native topomer by random sampling in just ≈100 ms. These results suggest that subsecond folding of modest-sized, single-domain proteins can be accomplished by a two-stage process of (i) topomer diffusion: random, diffusive sampling of the 3 × 10^7 distinct topomers to find the native topomer (≈0.1 s), followed by (ii) intratopomer ordering: nonrandom, local conformational rearrangements within the native topomer to settle into the precise native state

The Midlife Crisis of the Network Society

The network society is moving into some sort of middle age, or has at least normalized into the daily set of expectations people have for how they live their lives, not to mention consume news and information. In their adolescence, the technological and temporal affordances that have come with these new digital technologies were supposed to make the world better, or least they could have. There was much we did not foresee, such as the way that this brave new world would turn journalism into distributed content, not only taking away news organizations’ gatekeeping power but also their business model. This is indeed a midlife crisis. The present moment provides a vantage point for stocktaking and the mix of awe, nostalgia, and ruefulness that comes with maturity.Ope

Comparisons of Salmonella conjugation and virulence gene hyperexpression mediated by rumen protozoa from domestic and exotic ruminants

Recent studies have identified a phenomenon in which ciliated protozoa engulf Salmonella and the intra-protozoal environment hyperactivates virulence gene expression and provides a venue for conjugal transfer of antibiotic resistance plasmids. The former observation is relegated to Salmonella bearing the SGI1 multiresistance integron while the latter phenomenon appears to be a more generalized event for recipient Salmonella. Our previous studies have assessed virulence gene hyperexpression only with protozoa from the bovine rumen while conjugal transfer has been demonstrated in rumen protozoa from cattle and goats. The present study examined virulence gene hyperexpression for Salmonella exposed to rumen protozoa obtained from cattle, sheep, goats, or two African ruminants (giraffe and bongo). Conjugal transfer was also assessed in these protozoa using Salmonella as the recipient. Virulence gene hyperexpression was only observed following exposure to the rumen protozoa from cattle and sheep while elevated virulence was also observed in these animals. Conjugal transfer events were, however, observed in all protozoa evaluated. It therefore appears that the protozoa-based hypervirulence is not universal to all ruminants while conjugal transfer is more ubiquitous