is a commensal of the human gastrointestinal tract that can persist in the external environment and is a leading cause of hospital-acquired infections. Given its diverse habitats, the organism has ...developed numerous strategies to survive a multitude of environmental conditions. Previous studies have demonstrated that
will incorporate fatty acids from bile and serum into its membrane, resulting in an induced tolerance to membrane-damaging agents. To discern whether all fatty acids induce membrane stress protection, we examined how
responded to individually supplied fatty acids.
readily incorporated fatty acids 14 to 18 carbons in length into its membrane but poorly incorporated fatty acids shorter or longer than this length. Supplementation with saturated fatty acids tended to increase generation time and lead to altered cellular morphology in most cases. Further, exogenously supplied saturated fatty acids did not induce tolerance to the membrane-damaging antibiotic daptomycin. Supplementation with unsaturated fatty acids produced variable growth effects, with some impacting generation time and morphology. Exogenously supplied unsaturated fatty acids that are normally produced by
and those that are found in bile or serum could restore growth in the presence of a fatty acid biosynthetic inhibitor. However, only the eukaryote-derived fatty acids oleic acid and linoleic acid provided protection from daptomycin. Thus, exogenous fatty acids do not lead to a common physiological effect on
The organism responds uniquely to each, and only host-derived fatty acids induce membrane protection.
is a commonly acquired hospital infectious agent with resistance to many antibiotics, including those that target its cellular membrane. We previously demonstrated that
will incorporate fatty acids found in human fluids, like serum, into its cellular membrane, thereby altering its membrane composition. In turn, the organism is better able to survive membrane-damaging agents, including the antibiotic daptomycin. We examined fatty acids commonly found in serum and those normally produced by
to determine which fatty acids can induce protection from membrane damage. Supplementation with individual fatty acids produced a myriad of different effects on cellular growth, morphology, and stress response. However, only host-derived unsaturated fatty acids provided stress protection. Future studies are aimed at understanding how these specific fatty acids induce protection from membrane damage.
Summary
A critical question surrounding emergence of novel strains of avian influenza viruses (AIV) is the ability for wild migratory birds to translocate a complete (unreassorted whole genome) AIV ...intercontinentally. Virus translocation via migratory birds is suspected in outbreaks of highly pathogenic strain A(H5N1) in Asia, Africa and Europe. As a result, the potential intercontinental translocation of newly emerging AIV such as A(H7N9) from Eurasia to North America via migratory movements of birds remains a concern. An estimated 2.91 million aquatic birds move annually between Eurasia and North America with an estimated AIV prevalence as high as 32.2%. Here, we present a rapid assessment to address the likelihood of whole (unreassorted)‐genome translocation of Eurasian strain AIV into North America. The scope of this assessment was limited specifically to assess the weight of evidence to support the movement of an unreassorted AIV intercontinentally by migratory aquatic birds. We developed a rapid assessment framework to assess the potential for intercontinental movement of avian influenzas by aquatic birds. This framework was iteratively reviewed by a multidisciplinary panel of scientific experts until a consensus was established. Our assessment framework identified four factors that may contribute to the potential for introduction of any AIV intercontinentally into North America by wild aquatic birds. These factors, in aggregate, provide a framework for evaluating the likelihood of new forms of AIV from Eurasia to be introduced by aquatic birds into North America. Based on our assessment, we determined that the potential for introduction of A(H7N9) into North America through aquatic migratory birds is possible, but the likelihood ranges from extremely low to low.
Plasma-treated carbon thin films are investigated as counter electrodes for dye-sensitized solar cells. The films were grown onto fluorine-doped tin oxide (FTO) substrates by magnetron sputtering ...using pure graphite target and argon atmosphere and subsequently annealed at 600 °C for 30 min in vacuum. These films were then submitted to a plasma texturing process in a reactive ion etching reactor using three different gas combinations: sulfur hexafluoride/argon (SF
6
+ Ar), sulfur hexafluoride/hydrogen (SF
6
+ H
2
), and sulfur hexafluoride/oxygen (SF
6
+ O
2
). The morphology and structure of the obtained films were characterized by scanning electron microscopy and Raman spectroscopy. Cyclic voltammetry technique allowed accessing the improvements in their catalytic properties, while the photocurrent-voltage curves under simulated solar illumination AM 1.5G (100 mW/cm
2
) evaluated the performance of the respective assembled solar cells. The results show that photovoltaic performance is significantly affected by the different plasma texturing conditions used. The carbon counter electrode obtained after SF
6
+ O
2
plasma texturing achieved the best power conversion efficiency of 2.23%, which is comparable to the 2.31% obtained using the commercial platinum counter electrode.
Graphical abstract
Reactive Ion Etching reactor for plasma texturing process of carbon thin films
Prospective, randomised controlled trial.
To evaluate the effect of alendronate on bone mineral density in chronic spinal cord injury (SCI) patients.
University-based rehabilitation centre in São ...Paulo, Brazil.
A total of 19 chronic SCI patients were evaluated, divided into a control group and an experimental group. Control group patients received 1000 mg of calcium daily, and experimental group patients received 1000 mg of calcium plus 10 mg of alendronate daily. The study duration was 6 months. In all, 12 densitometric parameters were analysed using whole-body dual-energy X-ray absorptiometry at baseline and after 6 months.
The experimental group presented increases in nine densitometric parameters, although statistical significance was attained in only two of those parameters. In the control group, an increase was observed in only one parameter, whereas the remaining 11 presented either no alteration or a decrease.
The use of alendronate had a positive effect on bone mineral density in SCI patients and therefore represents a potential tool for prevention and treatment of osteoporosis in this population.
Combining chemical and mechanical properties of diamond-like carbon (DLC) films opens the possibilities for its use in electrochemical applications. DLC electrochemical corrosion behavior is heavily ...dependent on deposition techniques and precursor gas. In this paper, nanocrystalline diamond (NCD) particles were incorporated into DLC films to study NCD-DLC electrochemical corrosion resistance in biomedical area. The films were grown over 316L stainless steel using plasma enhanced chemical vapor deposition. NCD particles were incorporated into DLC during the deposition. Raman scattering spectroscopy and scanning electron microscopy characterized NCD-DLC structure and morphology. Electrochemical Impedance Spectroscopy and potentiodynamic method investigate NCD-DLC electrochemical corrosion behavior in simulated body fluid. The presence of NCD particles increases the DLC corrosion resistance. However, as the NCD concentration increases, the disorder also increases. Therefore, DLC films at lower concentration of NCD particles had the maximum corrosion resistance. From these results, NCD-DLC films can be considered a potential candidate for an anticorrosion material in biomedical applications.
NCD-DLC films presented superior impedance values compared to DLC films. The film disorder and H content contribute to reduce the film pores and then reduce the electrochemical corrosion. Display omitted
•NCD-DLC films presented superior impedance values as compared to DLC films.•The film disorder and H content contribute to reduce the film pores.•The film disorder and H content contribute to reduce the electrochemical corrosion.
Infections by larval stages of tapeworms of the genus Echinococcus (echinococcosis or hydatid disease) are zoonotic infections of major public health importance throughout much of the world. Humans ...become infected through accidental ingestion of eggs passed in faeces of canid definitive hosts. Tibetan populations of China have some of the highest documented levels of infections by both Echinococcus granulosus and E. multilocularis, the causes of cystic and alveolar echinococcosis, respectively. In this study we measured the prevalence of cystic (CE) and alveolar (AE) echinococcosis disease in Tibetan communities in Qinghai, Province, China, and identified putative risk factors for both infections in these communities. 3703 volunteers in three predominately Tibetan counties of Qinghai were surveyed between June 1997 and June 1998. Parasitic lesions were diagnosed by imaging of characteristic space-occupying lesions in abdominal organs (ultrasound) or the lungs (radiographs). Specific serodiagnostic assays (Dot-ELISA and Em2-ELISA) were performed on sera of positively imaged subjects to further distinguish the disease agent. All participants completed a questionnaire documenting age, sex, education level, occupation, lifestyle (nomadic or settled), slaughter practices, drinking water source, hygienic practice and association with dogs. Data were analyzed using SAS version 8. 6.6% of the volunteers had image-confirmed infection with E. granulosus (CE) and 0.8% had E. multilocularis (AE) infection. The significant univariate factors for echinococcal infection (both CE and AE) included livestock ownership, Tibetan ethnicity, female gender, low income, herding occupation, limited education, water source, age greater than 25 years old, poor hygienic practices, offal disposal practices and dog care. Multivariate analysis revealed that livestock ownership was a significant risk factor for both forms of the disease, as well as age greater than 25 years, female gender, herding occupation, and being nomadic (vs semi-nomadic or settled). No additional significant risk factors were identified among the 344 nomadic participants. Being female and being older than 25 years of age were significant factors among the 1906 semi-nomadic participants. Among the 1445 settled participants, allowing dogs to sleep indoors was statistically significant. Issues such as inadequate assessment of animal ownership, selection bias, disease misclassification, and loss of information may have led to reduction in strength of some risk factor associations and need to be addressed in future epidemiologic analysis of echinococcosis in this population.
Gold oxide nanoparticles were incorporated into diamond-like carbon (DLC) films in order to improve protection of AISI-1020 from electrochemical corrosion. The AuOx:DLC films were prepared by plasma ...enhanced chemical vapor deposition and were subsequently characterized by scanning electron microscopy, Raman spectroscopy and electrochemistry measurements. The electrochemical corrosion performance of the AuOx:DLC coating was contrasted to AISI-1020 and DLC without AuOx coating. The electrochemical techniques that were utilized for this investigation were potentiodynamic and electrochemistry impedance spectroscopy. The electrochemical analysis indicated that AuOx:DLC films presented superior corrosion resistance as compared to DLC. This resulted in 99.8% and 96.8% protection efficiency respectively, when compared to AuOx:DLC and DLC coatings.
The corrosion potential shifts positively when Au nanoparticles are presented in DLC structure, which is consistent with improved corrosion protection. The reduction in anodic current by four orders of magnitude is consistent with a reduced rate of corrosion. Gold nanoparticles possibly decrease the porosity, increase the barrier properties and increase sp3 C, which improve the corrosion resistance of DLC film. Display omitted
•Au-DLC films presented superior impedance values as compared to DLC films.•The corrosion potential shifts for less negative values when Au nanoparticles are incorporated in DLC structure.•Gold nanoparticles prevent aggressive ions from attacking the substrate and thereby improve the corrosion resistance..
Enterococcus faecalis is a commensal bacterium of the gastrointestinal tract that can cause nosocomial infections in immunocompromised humans. The hallmarks of this organism are its ability to ...survive in a variety of stressful habitats and, in particular, its ability to withstand membrane damage. One strategy used by E. faecalis to protect itself from membrane-damaging agents, including the antibiotic daptomycin, involves incorporation of exogenous fatty acids from bile or serum into the cell membrane. Additionally, the response regulator LiaR (a member of the LiaFSR lipid II-interacting antibiotic response regulator and sensor system associated with cell envelope stress responses) is required for the basal level of resistance E. faecalis has to daptomycin-induced membrane damage. This study aimed to determine if membrane fatty acid changes could provide protection against membrane stressors in a LiaR-deficient strain of E. faecalis We noted that despite the loss of LiaR, the organism readily incorporated exogenous fatty acids into its membrane, and indeed growth in the presence of exogenous fatty acids increased the survival of LiaR-deficient cells when challenged with a variety of membrane stressors, including daptomycin. Combined, our results suggest that E. faecalis can utilize both LiaR-dependent and -independent mechanisms to protect itself from membrane damage.
Enterococcus faecalis is responsible for a significant number of nosocomial infections. Worse, many of the antibiotics used to treat E. faecalis infection are no longer effective, as this organism has developed resistance to them. The drug daptomycin has been successfully used to treat some of these resistant strains; however, daptomycin-resistant isolates have been identified in hospitals. Many daptomycin-resistant isolates are found to harbor mutations in the genetic locus liaFSR, which is involved in membrane stress responses. Another mechanism shown to increase tolerance to daptomycin involves the incorporation of exogenous fatty acids from host fluids like serum or bile. This improved tolerance was found to be independent of liaFSR and suggests that there are additional ways to impact sensitivity to daptomycin. Thus, further studies are needed to understand how host fatty acid sources can influence antibiotic susceptibility.
Aldehyde oxidase (AO; EC 1.2.3.1) that could oxidize indole-3-acetaldehyde into indole-3-acetic acid was purified approximately 2000-fold from coleoptiles of 3-d-old maize (Zea mays L.) seedlings. ...The apparent molecular mass of the native enzyme was about 300 kD as estimated by gel-filtration column chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the enzyme was composed of 150-kD subunits. It contained flavin adenine dinucleotide, iron, and molybdenum as prosthetic groups and had absorption peaks in the visible region (300-600 nm). To our knowledge, this is the first demonstration of the presence of flavin adenine dinucleotide and metals in plant AO. Other aromatic aldehydes such as indole-3-aldehyde and benzaldehyde also served as good substrates, but N-methylnicotinamide, a good substrate for animal AO, was not oxidized. 2-Mercaptoethanol, p-chloromercuribenzoate, and iodoacetate partially inhibited the activity, but well-known inhibitors of animal AO, such as menadione and estradiol, caused no reduction in activity. These results indicate that, although maize AO is similar to animal enzymes in molecular mass and cofactor components, it differs in substrate specificity and susceptibility to inhibitors. Immunoblotting analysis with mouse polyclonal antibodies raised against the purified maize AO showed that the enzyme was relatively rich in the apical region of maize coleoptiles. The possible role of this enzyme is discussed in relation to phytohormone biosynthesis in plants.
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