| 1. |
|
|
| 2. |
- Arcibal, Imee G, et al.
(författare)
-
Recent advances in capillary electrophoretic analysis of individual cells
- 2007
-
Ingår i: Analytical and Bioanalytical Chemistry. - : Springer Science and Business Media LLC. - 1618-2642 .- 1618-2650. ; 387:1, s. 51-57
-
Tidskriftsartikel (refereegranskat)abstract
- Because variability exists within populations of cells, single-cell analysis has become increasingly important for probing complex cellular environments. Capillary electrophoresis (CE) is an excellent technique for identifying and quantifying the contents of single cells owing to its small volume requirements and fast, efficient separations with highly sensitive detection. Recent progress in both whole-cell and subcellular sampling has allowed researchers to study cellular function in the areas of neuroscience, oncology, enzymology, immunology, and gene expression.
|
|
| 3. |
|
|
| 4. |
- Ostrowski, Sara G, et al.
(författare)
-
Secondary Ion MS Imaging To Relatively Quantify Cholesterol in the Membranes of Individual Cells from Differentially Treated Populations
- 2007
-
Ingår i: Analytical chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 79:10, s. 3554-3560
-
Tidskriftsartikel (refereegranskat)abstract
- Time-of-flight secondary ion mass spectrometry (TOF-SIMS) is a well-established bioanalytical method for directly imaging the chemical distribution across single cells. Here we report a protocol for the use of SIMS imaging to comparatively quantify the relative difference in cholesterol level between the plasma membranes of two cells. It should be possible to apply this procedure to the study of other selected lipids. This development enables direct comparison of the chemical effects of different drug treatments and incubation conditions in the plasma membrane at the single-cell level. Relative, quantitative TOF-SIMS imaging has been used here to compare macrophage cells treated to contain elevated levels of cholesterol with respect to control cells. In situ fluorescence microscopy with two different membrane dyes was used to discriminate morphologically similar but differentially treated cells prior to SIMS analysis. SIMS images of fluorescently identified cells reveal that the two populations of cells have distinct outer leaflet membrane compositions with the membranes of the cholesterol-treated macrophages containing more than twice the amount of cholesterol of control macrophages. Relative quantification with SIMS to compare the chemical composition of single cells can provide valuable information about normal biological functions, causative agents of diseases, and possible therapies for diseases.
|
|
| 5. |
- Piehowski, Paul D., et al.
(författare)
-
MS/MS Methodology To Improve Subcellular Mapping of Cholesterol Using TOF-SIMS
- 2008
-
Ingår i: Anal. Chem.. - : American Chemical Society (ACS). ; 80:22, s. 8662-8667
-
Tidskriftsartikel (refereegranskat)abstract
- Time-of-flight secondary ion mass spectrometry (TOF-SIMS) can be utilized to map the distribution of various molecules on a surface with submicrometer resolution. Much of its biological application has been in the study of membrane lipids, such as phospholipids and cholesterol. Cholesterol is a particularly interesting molecule due to its involvement in numerous biological processes. For many studies, the effectiveness of chemical mapping is limited by low signal intensity from various biomolecules. Because of the high energy nature of the SIMS ionization process, many molecules are identified by detection of characteristic fragments. Commonly, fragments of a molecule are identified using standard samples, and those fragments are used to map the location of the molecule. In this work, MS/MS data obtained from a prototype C60+/quadrupole time-of-flight mass spectrometer was used in conjunction with indium LMIG imaging to map previously unrecognized cholesterol fragments in single cells. A model system of J774 macrophages doped with cholesterol was used to show that these fragments are derived from cholesterol in cell imaging experiments. Examination of relative quantification experiments reveals that m/z 147 is the most specific diagnostic fragment and offers a 3-fold signal enhancement. These findings greatly increase the prospects for cholesterol mapping experiments in biological samples, particularly with single cell experiments. In addition, these findings demonstrate the wealth of information that is hidden in the traditional TOF-SIMS spectrum.
|
|
| 6. |
- Santillo, Michael F, et al.
(författare)
-
Flow characterization of a microfluidic device to selectively and reliably apply reagents to a cellular network
- 2007
-
Ingår i: Lab on aChip. - 1473-0197 .- 1473-0189. ; 7, s. 1212-1215
-
Tidskriftsartikel (refereegranskat)abstract
- A three-dimensional microfluidic device has been successfully fabricated and the flow streams characterized for eventual use in studying communication in an in vitro network of nerve cells. The microfluidic system is composed of two layers of channels: a lower layer for the delivery of pharmacological solutions and an upper layer of channels used to direct the flow of the pharmacological solution streams and perfuse the cells with media and nutrients. Flow profiles have been characterized with computational fluid dynamics simulations, confocal fluorescence microscopy, and carbon-fiber amperometry, which have been used to map changes in flow profiles at different bulk flow rates. Ultimately, the microfluidic system and incorporated cell network will show how networked neurons adapt, compensate, and recover after being exposed to different chemical compounds.
|
|
| 7. |
- Adams, Kelly L., et al.
(författare)
-
In Vitro Electrochemistry of Biological Systems
- 2008
-
Ingår i: Annual Reviews of Analytical Chemistry. - : Annual Reviews. - 1936-1327 .- 1936-1335. ; 1, s. 329-355
-
Tidskriftsartikel (refereegranskat)abstract
- This article reviews recent work involving electrochemical methods for in vitro analysis of biomolecules, with an emphasis on detection and manipulation at and of single cells and cultures of cells. The techniques discussed include constant potential amperometry, chronoamperometry, cellular electroporation, scanning electrochemical microscopy, and microfluidic platforms integrated with electrochemical detection. The principles of these methods are briefly described, followed in most cases with a short description of an analytical or biological application and its significance. The use of electrochemical methods to examine specific mechanistic issues in exocytosis is highlighted, as a great deal of recent work has been devoted to this application.
|
|
| 8. |
- Ding, J., et al.
(författare)
-
Inhibition of HMGCoA Reductase Reveals An Unexpected Role for Cholesterol During PGC Migration in the Mouse.
- 2008
-
Ingår i: BMC developmental biology. - 1471-213X. ; 8:1
-
Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT: BACKGROUND: Primordial germ cells (PGCs) are the embryonic precursors of the sperm and eggs. Environmental or genetic defects that alter PGC development can impair fertility or cause formation of germ cell tumors. RESULTS: We demonstrate a novel role for cholesterol during germ cell migration in mice. Cholesterol was measured in living tissue dissected from mouse embryos and was found to accumulate within the developing gonads as germ cells migrate to colonize these structures. Cholesterol synthesis was blocked in culture by inhibiting the activity of HMG CoA reductase (HMGCR) resulting in germ cell survival and migration defects. These defects were rescued by co-addition of isoprenoids and cholesterol, but neither compound alone was sufficient. In contrast, loss of the last or penultimate enzyme in cholesterol biosynthesis did not alter PGC numbers or position in vivo. However embryos that lack these enzymes do not exhibit cholesterol defects at the stage at which PGCs are migrating. This demonstrates that during gestation, the cholesterol required for PGC migration can be supplied maternally. CONCLUSIONS: In the mouse, cholesterol is required for PGC survival and motility. It may act cell-autonomously by regulating clustering of growth factor receptors within PGCs or non cell-autonomously by controlling release of growth factors required for PGC guidance and survival.
|
|
| 9. |
- Dong, Yan, et al.
(författare)
-
Amperometric measurements of catecholamine release from single vesicles in MN9D cells.
- 2008
-
Ingår i: Journal of neurochemistry. - : Wiley. - 1471-4159 .- 0022-3042. ; 107:6, s. 1589-95
-
Tidskriftsartikel (refereegranskat)abstract
- MN9D cells have been used as a successful model to investigate dopamine pharmacology and to test the specific effects of drugs for the treatment of Parkinson's disease. However, quantitative measurements of quantal release from these cells have not been carried out. In this work, we used amperometry to investigate catecholamine release from MN9D cells. Amperometric events were observed in both undifferentiated and differentiated (butyric acid-treated) cells. An increase in quantal size and half-width was observed for differentiated cells versus undifferentiated cells; however, the number of events per cell and the amplitude remained constant. In transmission electron microscopy images, no obvious cluster of small synaptic vesicles was observed, and large dense-core vesicles were present in the cell body of undifferentiated cells; however, after differentiation, vesicles were concentrated in the cell processes. In differentiated cells, l-DOPA caused an increase in quantal size and half-width, which could be blocked by the vesicular monoamine transporter inhibitor, reserpine.
|
|
| 10. |
- Eves, D J, et al.
(författare)
-
Electrochemistry inside and outside single nerve cells
- 2007
-
Ingår i: New Frontiers in Ultrasensitive Bioanalysis: Advanced Analytical ChemistryApplications in Nanobiotechnology, Single Molecule Detection, and Single Cell Analysis. - Hoboken : John Wiley & Sons. ; , s. 215-234
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
|
|
