• Tonnesen Crockett posted an update 1 week, 2 days ago

    Background Aeromonas hydrophila is an important water-borne pathogen that leads to a great economic loss in aquaculture. Along with the abuse of antibiotics, drug-resistant strains rise rapidly. In addition, the biofilms formed by this bacterium limited the antibacterial effect of antibiotics. Bacteriophages have been attracting increasing attention as a potential alternative to antibiotics against bacterial infections. Results Five phages against pathogenic A. hydrophila, named N21, W3, G65, Y71 and Y81, were isolated. Morphological analysis by transmission electron microscopy revealed that phages N21, W3 and G65 belong to the family Myoviridae, while Y71 and Y81 belong to the Podoviridae. These phages were found to have broad host spectra, short latent periods and normal burst sizes. They were sensitive to high temperature but had a wide adaptability to the pH. In addition, the phages G65 and Y81 showed considerable bacterial killing effect and potential in preventing formation of A. hydrophila biofilm; and the phages G65, W3 and N21 were able to scavenge mature biofilm effectively. Phage treatments applied to the pathogenic A. hydrophila in mice model resulted in a significantly decreased bacterial loads in tissues. see more Conclusions Five A. hydrophila phages were isolated with broad host ranges, low latent periods, and wide pH and thermal tolerance. And the phages exhibited varying abilities in controlling A. hydrophila infection. This work presents promising data supporting the future use of phage therapy.Significance Chronic wounds are one of the major burdens of the U.S. health care system with an annual cost of $31.7 billion and affecting an estimated 2.4-4.5 million people. Several underlying molecular and cellular pathophysiological mechanisms, including poor vascularization, excessive extracellular matrix (ECM) degradation by proteases, decreased growth factor activity, and bacterial infection can lead to chronic wounds. More effective wound therapies need to address one or more of these mechanisms to significantly advance wound care. Recent Advances Self-assembled nanomaterials may provide new therapeutic options for chronic wound healing applications as those materials generally exhibit excellent biocompatibility and can bear multiple functionalities, such as ECM-mimicking properties, drug delivery capabilities, and tunable mechanics. Furthermore, self-assembled nanomaterials can be produced at low cost, and owing to their ability to self-organize, generate complex multifunctional structures that can be tailored to the varying sizes and shapes of chronic wounds. Self-assembled nanomaterials have been engineered to serve as wound dressings, growth factor delivery systems, and antimicrobials. Critical Issues As there are many different types of self-assembled nanomaterials, which in turn have different mechanisms of self-assembly and physiochemical properties, one type of self-assembled nanomaterials may not be sufficient to address all underlying mechanisms of chronic wounds. However, self-assembled nanomaterials can be easily tailored, and developing multifunctional self-assembled nanomaterials that can address various targets in chronic wounds will be needed. Future Directions Future studies should investigate combinations of various self-assembled nanomaterials to take full advantage of their multifunctional properties.Ljungan virus (LV), which belongs to the Parechovirus genus in the Picornaviridae family, was first isolated from bank voles (Myodes glareolus) in Sweden in 1998 and proposed as a zoonotic agent. To improve knowledge of the host association and geographical distribution of LV, tissues from 1685 animals belonging to multiple rodent and insectivore species from 12 European countries were screened for LV-RNA using reverse transcriptase (RT)-PCR. In addition, we investigated how the prevalence of LV-RNA in bank voles is associated with various intrinsic and extrinsic factors. We show that LV is widespread geographically, having been detected in at least one host species in nine European countries. Twelve out of 21 species screened were LV-RNA PCR positive, including, for the first time, the red vole (Myodes rutilus) and the root or tundra vole (Alexandromys formerly Microtus oeconomus), as well as in insectivores, including the bicolored white-toothed shrew (Crocidura leucodon) and the Valais shrew (Sorex antinorii). Results indicated that bank voles are the main rodent host for this virus (overall RT-PCR prevalence 15.2%). Linear modeling of intrinsic and extrinsic factors that could impact LV prevalence showed a concave-down relationship between body mass and LV occurrence, so that subadults had the highest LV positivity, but LV in older animals was less prevalent. Also, LV prevalence was higher in autumn and lower in spring, and the amount of precipitation recorded during the 6 months preceding the trapping date was negatively correlated with the presence of the virus. Phylogenetic analysis on the 185 base pair species-specific sequence of the 5′ untranslated region identified high genetic diversity (46.5%) between 80 haplotypes, although no geographical or host-specific patterns of diversity were detected.In this article we seek to explain how safety mechanisms and risks evolve over time. The article focuses on a sociotechnical system, that of a polar traverse (a transport operation in a polar environment). In the study spanning a period of 27 years data were collected with ethnographic participative observations on three of the 56 traverses already achieved. Activities were traced from the whole 1398 daily reports and scale models of the convoy vehicles were used to reconstruct events during the traverses. Self-confrontation interviews were also conducted. A traverse feedback process was carried out which revealed that (1) whereas proactive safety is aimed at maintaining the continuous improvement of a system, reactive safety makes it possible to maintain the system’s level of safety; (2) the development of redundancy and mixed technology contribute positively to the safety system. Improvements made to the safety system, its dynamics, and embodied resilience are discussed as well as the study limitations and implications.