Fluorescence correlation and cross-correlation spectroscopy (FCS/FCCS) have enabled biologists to study processes of transport, binding, and enzymatic reactions in living cells. However, applying FCS and FCCS to samples such as whole blood and plasma is complicated as the fluorescence bursts of diffusing labels can be swamped by strong autofluorescence. Here we present cross-correlation spectroscopy based on two upconversion nanoparticles emitting at different wavelengths on the anti-Stokes side of a single excitation laser. This upconversion cross-correlation spectroscopy (UCCS) approach allows us to completely remove all Stokes shifted autofluorescence background in biological material such as plasma. As a proof of concept, we evaluate the applicability of UCCS to a homogeneous sandwich immunoassay for thyroid stimulating hormone measured in buffer solution and in plasma.
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http://dx.doi.org/10.1002/chem.201801962 | DOI Listing |
J Biol Chem
January 2025
Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, MI, 48202; Department of Physiology, Wayne State University School of Medicine, Detroit, MI, USA 48202. Electronic address:
The storage and release of triacylglycerol (TAG) in lipid droplets (LDs) is regulated by dynamic protein interactions. α/β hydrolase domain-containing protein 5 (ABHD5; also known as CGI-58) is a membrane/LD bound protein that functions as a co-activator of Patatin Like Phospholipase Domain Containing 2 (PNPLA2; also known as Adipose triglyceride lipase, ATGL) the rate-limiting enzyme for TAG hydrolysis. The dysregulation of TAG hydrolysis is involved in various metabolic diseases such as metabolic dysfunction-associated steatotic liver disease (MASLD).
View Article and Find Full Text PDFJ Biol Chem
January 2025
Genomics Research Center, Academia Sinica, Taipei, Taiwan; Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Yang Ming Chiao Tung University and Academia Sinica, Taipei, Taiwan; Department of Biochemical Science and Technology, National Taiwan University, Taipei, Taiwan; Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Institute of Biological Chemistry, Academia Sinica; Institute of Biochemical Sciences, National Taiwan University; Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Taiwan University and Academia Sinica, Taipei, Taiwan. Electronic address:
Tauopathies cover a range of neurodegenerative diseases in which natively unfolded tau protein aggregates and spreads in the brain during disease progression. To gain insights into the mechanism of tau structure and spreading, here, we examined the biochemical and cellular properties of human full-length wild-type and familial mutant tau, ΔK280, with a deletion at lysine 280. Our results showed that both wild-type and mutant tau are predominantly monomeric by analytical ultracentrifugation.
View Article and Find Full Text PDFPhys Med Biol
January 2025
Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong Special Administrative Region of China, People's Republic of China.
The propagation speed of a shear wave, whether externally or internally induced, in biological tissues is directly linked to the tissue's stiffness. The group shear wave speed (SWS) can be estimated using a class of time-of-flight (TOF) methods in the time-domain or phase speed-based methods in the frequency domain. However, these methods suffer from biased estimations or time-consuming computations, and they are especially prone to wave distortions incases.
View Article and Find Full Text PDFMagn Reson Chem
December 2024
Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Göttingen, Germany.
We investigate cross-correlation between B quadrupole and B-F dipole-dipole coupling in two BODIPY compounds and one bis(benzoxazol)methanide in partially oriented polystyrene (PS) samples. Especially for the bis(benzoxazol)methanide, the transitions for which the two interactions interfere con- or destructively clearly show distinct linewidths.
View Article and Find Full Text PDFMethods Mol Biol
December 2024
Simons Centre for the Study of Living Machines, National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India.
Fluorescence correlation spectroscopy (FCS) enables the measurement of fluctuations at fast timescales (typically few nanoseconds) and with high spatial resolution (tens of nanometers). This single-molecule measurement has been used to characterize single-molecule transport and flexibility of polymers and biomolecules such as DNA and RNA. Here, we apply this technique as dual-color fluorescence cross-correlation spectroscopy (dcFCCS) to identify the motor function of the tethering protein EEA1 and the small GTPase Rab5 by probing the flexibility changes through end-monomer fluctuations.
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