+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

An optical method for recording the activity of single transporters in membrane patches

, : An optical method for recording the activity of single transporters in membrane patches. Journal of Microscopy 192(Pt 2): 114-125

We have previously introduced an optical technique for recording the transport of fluorescent substrates by single membrane transporters. Referred to as optical single-transporter recording (OSTR), the method was restricted to cases in which membrane transporters occurred at extremely small densities, namely at one or a few transporters per cell. Here we describe the extension of OSCR from whole cells harbouring a small number of transporters to small membrane patches containing transporters at normal densities. A technique was developed for firmly attaching cells to isoporous filters, i.e. very thin transparent sheets containing homogeneous populations of cylindrical pores. The flux of fluorescent transport substrates across the tiny membrane pieces spanning the filter pores was measured by scanning microphotolysis, a combination of fluorescence microphotolysis and confocal laser scanning microscopy. The technique was tested by attaching erythrocytes to filters containing pores of 1.2, 2.0 or 3.0 microns diameter. After treating filter-attached erythrocyte membranes with streptolysin O, the transport of the fluorescent protein B-phycoerythrin through single streptolysin O pores was observed. From the flux data the functional radius of the streptolysin O pore was derived to be 12.5 +/- 0.9 nm, in very good agreement with previous electron microscopic estimates. The new technique features a number of unique properties: (i) the size of the membrane patch can be chosen within wide limits according to transporter density, (ii) transport can be recorded on many membrane patches in parallel, (iii) both influx and efflux may be analysed employing either photobleaching of fluorescent or photorelease of caged nonfluorescent substrates, (iv) two or more transport substrates may be monitored simultaneously. The new technique can be used, for instance, for analysing the activity of protein/particle pumps, a membrane transport domain not previously accessible to a single-transporter analysis.


PMID: 9853370

Other references

Masuzaki, H.; Tanaka, T.; Nakao, K., 2007: Metabolic syndrome: convergence of metabolic diseases based on obesity and dysfunction of adipose tissue. Nihon Rinsho. Japanese Journal of Clinical Medicine 64 Suppl 9: 17-22

Roux, M.; Vayre, P.; Bellanger, G.; Beaugeard, G., 1963: Postoperative Jejunal Ulcers. 2 Cases. Concours Medical 85: 90-90

Mohammadi, B.; Kollewe, K.; Samii, A.; Dengler, R.; Münte, T.F., 2011: Functional neuroimaging at different disease stages reveals distinct phases of neuroplastic changes in amyotrophic lateral sclerosis. Some previous functional magnetic resonance imaging (fMRI) studies have revealed increased activation in amyotrophic lateral sclerosis (ALS) patients but longitudinal data on such activation changes are lacking. To assess the time course of change...

Lawry, K.; Slomka, J.; Goldfarb, J., 1996: What went wrong: multiple perspectives on an adolescent's decision to refuse blood transfusions. Persons with religious beliefs that conflict with mainstream medical practice create a tension for clinicians between honoring the different religious perspectives of the individual or carrying out what they believe to be their professional obliga...

Marnay-Gulat, C.; Trung Tuong, M.D.; Raoul, Y., 1970: Scorbutic and hypocalcemia syndrome in guinea pigs deprived of medullo-adrenal glands. Comptes Rendus Hebdomadaires des Seances de L'academie des Sciences. Serie D: Sciences Naturelles 18: 2191-2194

Alpate'-Ev, A.; Kulik, M.; Razumova, L.; Sapozhnikova, S.; Chirkov, I., 1971: The agroclimatic character of primary agricultural regions of the USSR suitable for raising grain crops and as a basis for agrotechnical and reclamation measures. Melioratsiia Pochv v SSSR: -30

Pope Kevin O.; Ocampo Adriana C.; Fischer Alfred G.; Alvarez Walter; Fouke Bruce W.; Webster Clyde L.; Vega Francisco J.; Smit Jan; Fritsche A.E.gene; Claeys Philippe, 1999: Chicxulub impact ejecta from Albion Island, Belize. Impact ejecta from the Albion Formation are exposed in northern Belize. The ejecta come from the outer portion of the continuous ejecta blanket of the Chicxulub crater, which is located 360 km to the northwest. The basal unit of the Albion Formati...

Ferreira, P.A.; Borges Junior, J.C.F.; Silva Junior, A.G. da; Pruski, F.F., 2001: Agricultural drainage systems. Part II: Comparison between the developed model and other methodologies. This study aimed at comparing the results obtained from the developed model, PRODREN with those obtained from the DRAINMOD model thoroughly tested in the USA, and with the SIMDRENO model, as well as with methodologies traditionally used in dimensi...

Rawlinson W.D.; Tennant C.; Carter J.N., 1984: Dexamethasone suppression tests trh tests thyroid function and serum prolactin levels in patients with major depression. Endocrine Society of Australia Proceedings 27: 9

Froelich, J.; Milbrandt, J.C.; Allan, D.Gordon., 2009: Impact of the 80-hour workweek on surgical exposure and national in-training examination scores in an orthopedic residency program. This study examines the impact of the 80-hour workweek on the number of surgical cases performed by PGY-2 through PGY-5 orthopedic residents. We also evaluated orthopedic in-training examination (OITE) scores during the same time period. Data were...