| 1. |
- Hou, Zining, et al.
(författare)
-
Time lapse investigation of antibiotic susceptibility using a microfluidic linear gradient 3D culture device
- 2014
-
Ingår i: Lab on a Chip. - : Royal Society of Chemistry (RSC). - 1473-0197 .- 1473-0189. ; 14:17, s. 3409-3418
-
Tidskriftsartikel (refereegranskat)abstract
- This study reports a novel approach to quantitatively investigate the antibacterial effect of antibiotics on bacteria using a three-dimensional microfluidic culture device. In particular, our approach is suitable for studying the pharmacodynamics effects of antibiotics on bacterial cells temporally and with a continuous range of concentrations in a single experiment. The responses of bacterial cells to a linear concentration gradient of antibiotics were observed using time-lapse photography, by encapsulating bacterial cells in an agarose-based gel located in a commercially available microfluidics chamber. This approach generates dynamic information with high resolution, in a single operation, e. g., growth curves and antibiotic pharmacodynamics, in a well-controlled environment. No pre-labelling of the cells is needed and therefore any bacterial sample can be tested in this setup. It also provides static information comparable to that of standard techniques for measuring minimum inhibitory concentration (MIC). Five antibiotics with different mechanisms were analysed against wild-type Escherichia coli, Staphylococcus aureus and Salmonella Typhimurium. The entire process, including data analysis, took 2.5-4 h and from the same analysis, high-resolution growth curves were obtained. As a proof of principle, a pharmacodynamic model of streptomycin against Salmonella Typhimurium was built based on the maximal effect model, which agreed well with the experimental results. Our approach has the potential to be a simple and flexible solution to study responding behaviours of microbial cells under different selection pressures both temporally and in a range of concentrations.
|
|
| 2. |
- Zining, Hou, et al.
(författare)
-
A microfluidic approach for dynamic investigation of the antibiotic susceptibility of bacteria
- 2013
-
Ingår i: MME 2013 24th Micromechanics and Microsystems Europe Conference.
-
Konferensbidrag (refereegranskat)abstract
- The possibility to study the effect on cell growth of a chemical is a valued tool for re- searchers in different areas, such as antibiotic resis- tance, cancer research and metabolic pathways. Traditional approaches need long time and no dynamic information is given. Microfluidics offers short diffusion lengths and steeper gradients for studies of antibiotic susceptibility, which could improve throughput greatly. By combining with time-lapse micrography, information on the dynam- ics may provide additional understanding. A micro- fluidic 3D cell culture chip was used to determine the MIC (minimum inhibitory concentration) and the dynamics of sub-MIC of E. coli against ampicillin and spectinomycin. And the same works have been done in Staphylococcus aureus and Salmonella. It is the first time to reveal this dynamic behaviour of bacteria against antibiotics quantitatively in a micro- fludic device. It is anticipated that it could be ex- tended to many other similar investigations in bio- logical and relevant pharmaceutical or clinical applications.
|
|
| 3. |
- Arthurson, Veronica, et al.
(författare)
-
Effects on Glomus mosseae root colonization by Paenibacillus polymyxa and Paenibacillus brasilensis strains as related to soil P-availability in winter wheat
- 2011
-
Ingår i: Applied and Environmental Soil Science. - : Hindawi Limited. - 1687-7667 .- 1687-7675.
-
Tidskriftsartikel (refereegranskat)abstract
- Greenhouse experiments were conducted to assess the effects of inoculating winter wheat (Triticum aestivum) with plant growth promoting rhizobacteria (PGPR) of the genusPaenibacillusunder phosphate P-limited soil conditions in the presence or absence of the arbuscular mycorrhizal fungus (AMF)Glomus mosseae. FourP. polymyxastrains and oneP. brasilensisstrain were compared at two cell concentrations (106and 108 cells g−1seeds) of inoculation, and surface sterilized AMF spores were added to pots. Mycorrhizal root colonization, plant growth, and plant uptake of phosphorus were analyzed. Bacterial phosphate solubilization was examined separatelyin vitro. MostP. polymyxastrains, isolated from wheat, had dramatic effectsper seon root growth and root P-content. No treatment gave significant effect on shoot growth. AMF root colonization levels and total plant uptake of P were much stimulated by the addition of mostP. polymyxastrains. The AM fungus alone and theP. brasilensis, alone or in combination with the fungus, did not affect total plant P-levels. Our results indicate that practical application of inoculation with plant host-specific rhizobacteria (i.e.,P. polymyxa) could positively influence uptake of phosphorus in P-deficient soils by wheat plants, provided that suitable AM fungi (e.g.,G. mosseae) are present.
|
|
| 4. |
- Dahlin, Andreas P., et al.
(författare)
-
Methodological aspects on microdialysis protein sampling and quantification in biological fluids : an in vitro study on human ventricular CSF.
- 2010
-
Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 82:11, s. 4376-4385
-
Tidskriftsartikel (refereegranskat)abstract
- There is growing interest in sampling of protein biomarkers from the interstitial compartment of the brain and other organs using high molecular cutoff membrane microdialysis (MD) catheters. However, recent data suggest that protein sampling across such MD membranes is a highly complex process that needs to be further studied. Here, we report three major improvements for microdialysis sampling of proteins in complex biological matrixes. The improvements in this in vitro study using human ventricular cerebrospinal fluid as the sample matrix include increased fluid recovery control, decreased protein adsorption on the microdialysis membrane and materials, and novel quantitative mass spectrometry analysis. Dextrans in different concentrations and sizes were added to the perfusion fluid. It was found that dextrans with molecular mass 250 and 500 kDa provided a fluid recovery close to 100%. An improved fluid recovery precision could be obtained by self-assembly triblock polymer surface modification of the MD catheters. The modified catheters also delivered a significantly increased extraction efficiency for some of the investigated proteins. The final improvement was to analyze the dialysates with isobaric tagged (iTRAQ) proteomics, followed by tandem mass spectrometric analysis. By using this technique, 48 proteins could be quantified and analyzed with respect to their extraction efficiencies. The novel aspects of microdialysis protein sampling, detection, and quantification in biological fluids presented in this study should be considered as a first step toward better understanding and handling of the challenges associated with microdialysis sampling of proteins. The next step is to optimize the developed methodology in vivo.
|
|
| 5. |
- Ekström, Karin M., et al.
(författare)
-
"Det blir många nej" : konsumtionens meningar och villkor för barnfamiljer med knapp ekonomi
- 2010
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Under de senaste decennierna har konsumtion kommit att bli ett allt viktigare område för människor när det gäller att visa och uppfatta socioekonomisk status. Det finns även forskare (Bauman 1998) som hävdar att konsumtionen blivit viktigare än arbetet när det gäller att visa status. I ett överflödssamhälle som det svenska är det framförallt den symboliska och positionella konsumtionen som är betydelsefull, d.v.s. sådan konsumtion som syftar till att visa omgivningen hur man vill uppfattas. På ett förenklat sätt kan man säga att denna typ av konsumtion rymmer två olika drivkrafter, social emulering och social distinktion. Emulering innebär att konsumtionen syftar till att man vill uppfattas som de flesta, som majoriteten konsumenter. Distinktion innebär däremot att genom konsumtion visa att man är annorlunda än de flesta, att man är unik och sticker ut från mängden. Dessa två drivkrafter är centrala och betydelsefulla för vår kunskap om konsumtionens mening(ar). Forskningsmässigt har det huvudsakliga intresset varit inriktat mot distinktion, d.v.s. konsumtion som kan tolkas som nyare trender och som utmärker sig. Den andra drivkraften, den sociala emuleringen, den ibland kanske gråare och vardagligare konsumtionen har inte tilldragit sig samma intresse. Detta har bl.a. fått som konsekvens att det är konsumenter som ligger i framkanten av förändrade konsumtionsmönster som tilldrar sig intresset medan de som genom sin konsumtion strävar efter att uppfattas som majoriteten, som ”normala” och efterföljare till trendsättare inte studerats i samma omfattning.
|
|
| 6. |
- Ekström, Karin M., et al.
(författare)
-
Families Navigating the Landscape of Consumption in the Swedish Welfare Society
- 2010
-
Ingår i: Journal of Macromarketing. - : SAGE Publications. - 0276-1467 .- 1552-6534. ; 30:4, s. 366-374
-
Tidskriftsartikel (refereegranskat)abstract
- Swedish welfare policy has in several ways promoted the individual rather than the family as a unit. This is not a phenomenon happening only in Sweden, but one occurring in many other Western countries where individualization is strongly emphasized. Sweden is, however, interesting as an example of a country with deep collective roots regarding issues of welfare. The welfare state has been, and to a major part still is, the main provider of social services, a fact that has affected the Swedish family in certain ways. During the last decades, the Swedish welfare society has changed toward marketization implying that individuals and families have to take on more responsibility regarding their welfare. The aim of this article is to discuss the transformation of Swedish families as consumers reflecting upon the effects of the Swedish welfare society.
|
|
| 7. |
- Ekström, Karin M., et al.
(författare)
-
Försakelser och förhandlingar : vardag för barnfamiljer med knapp ekonomi
- 2011
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Under de senaste decennierna har konsumtion kommit att bli ett allt viktigare område för människor när det gäller att uttrycka och uppfatta socioekonomisk status. Det finns även forskare (Bauman 1998) som hävdar att konsumtion blivit viktigare än arbete när det gäller att visa status. I ett överflödssamhälle som det svenska är det framför allt den symboliska och positionella konsumtionen som är betydelsefull, d.v.s. sådan konsumtion som syftar till att visa omgivningen hur man vill uppfattas. På ett förenklat sätt kan man säga att denna typ av konsumtion rymmer två olika drivkrafter, social emulering och social distinktion. Emulering innebär att konsumtionen syftar till att man vill uppfattas som de flesta, som majoriteten konsumenter. Distinktion innebär däremot att genom konsumtion visa att man är annorlunda än de flesta, att man är unik och sticker ut från mängden.
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
|
|
