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Microplate based biosensing with a computer screen aided technique
Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, Faculty of Health Sciences.
2003 (English)In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 19, no 1, 35-41 p.Article in journal (Refereed) Published
Abstract [en]

Melanophores, dark pigment cells from the frog Xenopus laevis, have the ability to change light absorbance upon stimulation by different biological agents. Hormone exposure (e.g. melatonin or α-melanocyte stimulating hormone) has been used here as a reversible stimulus to test a new compact microplate reading platform. As an application, the detection of the asthma drug formoterol in blood plasma samples is demonstrated. The present system utilizes a computer screen as a (programmable) large area light source, and a standard web camera as recording media enabling even kinetic microplate reading with a versatile and broadly available platform, which suffices to evaluate numerous bioassays. Especially in the context of point of care testing or self testing applications these possibilities become advantageous compared with highly dedicated comparatively expensive commercial systems.

Place, publisher, year, edition, pages
2003. Vol. 19, no 1, 35-41 p.
National Category
Medical and Health Sciences
Identifiers
URN: urn:nbn:se:liu:diva-26777DOI: 10.1016/S0956-5663(03)00132-5Local ID: 11382OAI: oai:DiVA.org:liu-26777DiVA: diva2:247327
Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2012-10-12Bibliographically approved
In thesis
1. Melanophore signaling: regulation and application
Open this publication in new window or tab >>Melanophore signaling: regulation and application
2003 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Melanophores are pigment-containing cells responsible for quick physiological color changes in lower vertebrates due to redistribution of melanosomes, pigment granules. We have studied melanophores from African clawed frog, Xenopus laevis. Classically, melanosomes can be stimulated to aggregate in the cell center by the hormone melatonin via a process involving activation of the inhibitory Gi/o protein and inhibition of adenylate cyclase/cAMP/protein kinase A pathway. In addition, tyrosine phosphorylations have been shown to be crucial for aggregation. In this thesis, we demonstrate that mitogen-activated protein kinase (MAPK) are activated and phosphoinositol 3-kinase (PI3-K) are involved in melatonininduced aggregation. Inhibition of MAPK kinase or PI3-K inhibits MAPK activation, tyrosine phosphorylation of a 280-kDa protein and aggregation. Further, PI3-K inhibition is less dramatic in fish Labrus melanophores. Together with findings that phosphodiesterase (PDE) 4 and/or PDE2 are involved in keeping the aggregated state in Xenopus, we suggest that active PI3-K via MAPK stimulates PDE, thus lowering cAMP. We also use latrunculin A to induce aggregation via disruption of actin filaments. Kinetic studies indicate that melatonin and latrunculin share final downstream target, possibly inactivate myosin-V leading to melanosome aggregation. As biosensor application, a new computer screen assisted technique suitable for bioassays is demonstrated using melanophores to monitor kinetic responses of melanosome movement and blood plasma sample detection of the asthma drug and ß2 adrenergic agonist formoterol. We also used melanophores to examine the efficacy of enantiomers of formoterol. We confirm that (R;R)-formoterol is more potent than (S;S)-formoterol, in guinea pig tracheal ring preparations, cultured melanophores, and radioligand binding on COS-7 cells, but demonstrate and calculate that (S;S)-formoterol has more efficacy than previously described. Characterization of melanophores are important for biosensor applications, i e to understand mechanisms of drugs, and will probably also increase the knowledge of cell signaling in other cell systems.

Place, publisher, year, edition, pages
Linköping: Linköpings universitet, 2003. 64 p.
Series
Linköping University Medical Dissertations, ISSN 0345-0082 ; 799
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-27457 (URN)12110 (Local ID)91-7373-485-3 (ISBN)12110 (Archive number)12110 (OAI)
Public defence
2003-09-05, Aulan, Administrationshuset, Hälsouniversitet, Linköping, 13:00 (Swedish)
Opponent
Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2012-10-12Bibliographically approved

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Filippini, DanielAndersson, TonySvensson, SamuelLundström, Ingemar

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