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ATP measuring

Zahra Alavi, Giovanni Zocchi
Pursuing a materials science approach to understanding the deformability of enzymes, we introduce measurements of the phase of the mechanical response function within the nanorheology paradigm. Driven conformational motion of the enzyme is dissipative as characterized by the phase measurements. The dissipation originates both from the surface hydration layer and the interior of the molecule, probed by examining the effect of point mutations on the mechanics. We also document changes in the mechanics of the enzyme examined, guanylate kinase, upon binding its four substrates...
May 2018: Physical Review. E
David H Jang, Clinton J Orloski, Shawn Owiredu, Frances S Shofer, John C Greenwood, David M Eckmann
OBJECTIVE: Mitochondrial dysfunction has been implicated as a key cellular event leading to organ dysfunction in sepsis. Our objective is to measure changes in mitochondrial bioenergetics in subjects with early presentation of sepsis to provide insight into the incompletely understood pathophysiology of the dysregulated host response in sepsis. DESIGN: Prospective observational study SETTING:: Single site tertiary academic emergency department SUBJECTS:: We enrolled a total of 48 subjects were enrolled in the study, 10 with sepsis or septic shock, 10 with infection without sepsis, 14 older and 14 younger healthy controls...
June 13, 2018: Shock
U Wollina, C Wiegand, U-C Hipler
Soft tissue fillers are used in aesthetic medicine for volumizing and for contouring. Calcium hydroxylapatite (CaHA) is a fully biodegradable biostimulatory filler. The study presents results of in vitro biocompatibility and cytotoxicity investigations performed on CaHA and illustrates its clinical effects. We used a human cell culture model for in vitro studies with HaCaT keratinocytes and human dermal fibroblasts, known to be a sensitive cell type for biocompatibility and cytotoxicity. Cells were exposed to different concentrations of CaHA (Radiesse®)...
May 2018: Georgian Medical News
Shigeru Yamada, Daiju Yamazaki, Yasunari Kanda
Silver nanoparticles (AgNPs) have been widely used as consumer products due to their antibacterial activities. Despite their extensive use, AgNPs have been reported to cause various types of cytotoxicity, including neurotoxicity. However, the potential action of AgNPs on early fetal development has not been elucidated. This study determined the effects of AgNPs on neural induction in human induced pluripotent stem cells (iPSCs), used as a model for human fetal stage development. It was observed that exposure to AgNPs reduced the expression of several neural differentiation marker genes, including OTX2, an early biomarker for neurogenesis in iPSCs...
June 14, 2018: Nanotoxicology
Andreea Campu, Frederic Lerouge, Denis Chateau, Frederic Chaput, Patrice Baldeck, Stephane Parola, Dana Maniu, Ana-Maria Craciun, Adriana Vulpoi, Simion Astilean, Monica Focsan
In this work, we demonstrate the feasibility of gold bipyramidal-shaped nanoparticles (AuBPs) to be used as active plasmonic nanoplatforms for the detection of the biotin-streptavidin interaction in aqueous solution via both Localized Surface Plasmon Resonance and Surface Enhanced Raman Scattering (LSPR/SERS). Our proof of concept exploits the precise attachment of the recognition element at the tips of AuBPs where the electromagnetic field is stronger, which is beneficial to the surface sensitivity of longitudinal LSPR on the local refractive index, and to the electromagnetic enhancement of SERS activity too...
June 15, 2018: Analytical Chemistry
Wei Huang, Mikko Tikkanen, Yan-Fei Cai, Ji-Hua Wang, Shi-Bao Zhang
In the present study, we studied the role of chloroplastic ATP synthase in photosynthetic regulation during leaf maturation. We measured gas exchange, chlorophyll fluorescence, P700 redox state, and the electrochromic shift signal in mature and immature leaves. Under high light, the immature leaves displayed high levels of non-photochemical quenching (NPQ) and P700 oxidation ratio, and higher values for proton motive force (pmf) and proton gradient (ΔpH) across the thylakoid membranes but lower values for the activity of chloroplastic ATP synthase (gH + ) than the mature leaves...
June 11, 2018: Biochimica et Biophysica Acta
Joseph Powers, Charles Williams, Michael Regnier, Thomas Daniel
In striated muscle, the giant protein titin spans the entire length of a half-sarcomere and extends from the backbone of the thick filament, reversibly attaches to the thin filaments, and anchors to the dense protein network of the z-disk capping the end of the half-sarcomere. However, little is known about the relationship between the basic mechanical properties of titin and muscle contractility. Here, we build upon our previous multi-filament, spatially explicit computational model of the half-sarcomere by incorporating the nonlinear mechanics of titin filaments in the I-band...
June 12, 2018: Integrative and Comparative Biology
Ahmad Salimi, Jalal Pourahmad
Recent discoveries have focused on mitochondria functions in the neuroscience research for approaches to study mitochondria dysfunction in neurodegenerative diseases. Mitochondrion is one of the organelles that is possibly worst affected in cognitive impairments. These are known as "powerhouse" of the cell as they are the main source of generation of ATP through aerobic respiration. They have role in oxidative phosphorylation and metabolism, they play central role in cell differentiation, apoptosis, oxygen sensing and detoxification of reactive oxygen species, innate immunity, mitochondrial matrix calcium, and maintenance of cell quality and regulation of cytoplasmic...
2018: Methods in Molecular Biology
Simon T Bond, Kevin A McEwen, Prusothman Yoganantharajah, Yann Gibert
The Agilent Seahorse Extracellular Flux Analyzer can be used to measure the oxygen consumption rate (OCR) and extra cellular acidification rate (ECAR), from which mitochondrial bioenergetics measurements can be determined including basal respiration, respiration due to ATP turnover, uncoupled respiration/proton leak, and maximum respiration. This novel method demonstrates how to use a Seahorse XF 24 Extracellular Flux Analyzer to measure the bioenergetic flux of zebrafish embryos in vivo during development...
2018: Methods in Molecular Biology
Atsushi Mukaiyama, Yoshihiko Furuike, Jun Abe, Eiki Yamashita, Takao Kondo, Shuji Akiyama
KaiC, the core oscillator of the cyanobacterial circadian clock, is composed of an N-terminal C1 domain and a C-terminal C2 domain, and assembles into a double-ring hexamer upon ATP binding. Cyclic phosphorylation and dephosphorylation at Ser431 and Thr432 in the C2 domain proceed with a period of approximately 24 h in the presence of other clock proteins, KaiA and KaiB, but recent studies have revealed a crucial role for the C1 ring in determining the cycle period. In this study, we mapped dynamic structural changes of the C1 ring in solution using a combination of site-directed tryptophan mutagenesis and fluorescence spectroscopy...
June 11, 2018: Scientific Reports
Wenjun Xiong, Jinghai Hua, Zuheng Liu, Wanqiang Cai, Yujia Bai, Qiong Zhan, Wenyan Lai, Qingchun Zeng, Hao Ren, Dingli Xu
BACKGROUND: Mitochondrial quality control is crucial to the development of angiotensin II (AngII)-induced cardiac hypertrophy. PTEN induced putative kinase 1 (PINK1) is rapidly degraded in normal mitochondria but accumulates in damaged mitochondria, triggering autophagy to protect cells. PINK1 mediates mitophagy in general, but whether PINK1 mediates AngII-induced mitophagy and the effects of PINK1 on AngII-induced injury are unknown. This study was designed to investigate the function of PINK1 in an AngII stimulation model and its regulation of AngII-induced mitophagy...
September 1, 2018: International Journal of Cardiology
Nadia Farhat, Frederik Hammes, Emmanuelle Prest, Johannes Vrouwenvelder
The bacterial growth potential is important to understand and manage bacterial regrowth-related water quality concerns. Bacterial growth potential depends on growth promoting/limiting compounds, therefore, nutrient availability is the key factor governing bacterial growth potential. Selecting proper tools for bacterial growth measurement is essential for routine implementation of the growth potential measurement. This study proposes a growth potential assay that is universal and can be used for different water types and soil extract without restrictions of pure culture or cultivability of the bacterial strain...
June 6, 2018: Water Research
Angelika Długosz, Katarzyna Gach-Janczak, Jacek Szymański, Dariusz Deredas, Tomasz Janecki, Anna Janecka
BACKGROUND: The development of multidrug resistance to chemotherapy remains a challenge in the treatment of cancer and is a major factor causing failure of many forms of chemotherapy. The ATP binding cassette (ABC) family of proteins are efflux pumps that transport various potentially dangerous substances out of the cells. Several of the ABC transporters are related to chemoresistance, as the rapidly dividing malignant cells use them to protect themselves from medical interventions. Inhibitors of ABC transporters have the potential to enhance the efficacy of anticancer drugs...
January 10, 2018: Pharmacological Reports: PR
Sarah Innes-Gold, Christopher J Luby, Charles R Mace
We construct a mathematical model describing the equilibrium flotation height of a spherical particle at the interface of immiscible liquids. The behavior of such a system depends on several experimentally measurable parameters, which include surface tensions, densities of all phases, and system scale. These parameters can be absorbed into three quantities that entirely determine the equilibrium position of the particle: the contact angle between the interface and particle, the Bond number, and the ratio of particle buoyant density to liquid phase densities-a new, dimensionless number that we introduce here...
June 8, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Mitzi Nagarkatti, Sadiye Amcaoglu Rieder, Prakash S Nagarkatti
Immunotoxicity testing is important in determining the toxic effects of various chemicals on the immune system. The immune system is a direct target of numerous toxicants, and the adverse effects include serious health complications such as susceptibility to infections, cancer, allergic reactions, and autoimmune diseases. One way to investigate the harmful effects of different chemicals is to study apoptosis and/or proliferation in immune cells. Apoptosis is defined as programmed cell death, and in general, this process helps in development and maintenance of tolerance and homeostasis...
2018: Methods in Molecular Biology
Erchao Li, Derek G Bolser, Kevin J Kroll, Erica K Brockmeier, Francesco Falciani, Nancy D Denslow
Phenols are classified as polar narcotics, which are thought to cause toxicity by non-specific mechanisms, possibly by disrupting membrane structure and function. Here we test three phenolic chemicals, phenol, 2,4-dichlorphenol and pentachlorophenol on embryo development, heartbeat rate and mitochondrial respiration in fathead minnow (Pimephales promelas). While these chemicals have been used on isolated mitochondria, they have not yet been used to verify respiration in intact embryos. Mitochondrial respiration in intact embryos was measured after optimizing the Seahorse XFe24 Extracellular Flux Analyzer...
May 29, 2018: Aquatic Toxicology
Christopher M Gonçalves, Daniel K Mulkey
KEY POINTS: changes in CO2 result in corresponding changes in both H+ and HCO3 - and despite evidence that HCO3 - can function as an independent signaling molecule, there is little evidence suggesting HCO3 - contributes to respiratory chemoreception. We show that HCO3 - directly activates chemosensitive RTN neurons. Identifying all relevant signaling molecules is essential for understanding how chemoreceptors function, and since HCO3 - and H+ are buffered by separate cellular mechanisms, having the ability to sense both modalities adds additional information regarding changes in CO2 that are not necessarily reflected by pH alone...
June 5, 2018: Journal of Physiology
Angela L D'Rozario, Delwyn J Bartlett, Keith K H Wong, Toos Sach, Qiao Yang, Ronald R Grunstein, Caroline D Rae
Study Objectives: Obstructive sleep apnea (OSA) is a well-established cause of impaired daytime functioning. However, there is a complex inter-individual variability in neurobehavioural performance in OSA patients. We previously reported compromised brain bioenergetics during apneic sleep in severe OSA. In this study, we investigate whether brain bioenergetics during resting wakefulness are related to neurobehavioural performance. Methods: Patients attended the sleep laboratory in the evening and were kept awake over-night...
June 1, 2018: Sleep
Serena Varesano, Maria Raffaella Zocchi, Alessandro Poggi
New successful anti-cancer strategies are based on the stimulation of immune reaction against tumors: however, preclinical testing of such treatments is still a challenge. To improve the screening of anti-cancer drugs, three-dimensional (3D) culture systems, including spheroids, have been validated as preclinical models. We propose the spheroid 3D system to test anti-tumor drug-induced immune responses. We show that colorectal carcinoma (CRC) spheroids, generated with the epithelial growth factor (EGF), can be co-cultured with Vδ2 T cells to evaluate the anti-tumor activity of these effector lymphocytes...
2018: Frontiers in Immunology
Matthias Steglich, Julia D Hofmann, Julia Helmecke, Johannes Sikorski, Cathrin Spröer, Thomas Riedel, Boyke Bunk, Jörg Overmann, Meina Neumann-Schaal, Ulrich Nübel
We report the frequent, convergent loss of two genes encoding the substrate-binding protein and the ATP-binding protein of an ATP-binding cassette (ABC) transporter from the genomes of unrelated Clostridioides difficile strains. This specific genomic deletion was strongly associated with the reduced uptake of tyrosine and phenylalanine and production of derived Stickland fermentation products, including p -cresol, suggesting that the affected ABC transporter had been responsible for the import of aromatic amino acids...
2018: Frontiers in Microbiology
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