scholarly journals Array of individually addressable two-electrode electrochemical cells sharing a single counter/reference electrode for multiplexed enzyme activity measurements

2022 ◽  
pp. 113952
Author(s):  
Manuel Gutiérrez-Capitán ◽  
Antoni Baldi ◽  
Ángel Merlos ◽  
César Fernández-Sánchez
Keyword(s):  
Enzyme Activity ◽  
Reference Electrode ◽  
Electrochemical Cells ◽  
Activity Measurements ◽  
Single Counter

scholarly journals Printed, Flexible Lactate Sensors: Design Considerations Before Performing On-Body Measurements

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Margaret E. Payne ◽  
Alla Zamarayeva ◽  
Veronika I. Pister ◽  
Natasha A. D. Yamamoto ◽  
Ana Claudia Arias
Keyword(s):  
Enzyme Activity ◽  
Salt Concentration ◽  
Reference Electrode ◽  
Body Measurements ◽  
Lactate Oxidase ◽  
Buffer Solution ◽  
Counter Electrodes ◽  
Sensor Performance ◽  
Activity Measurements ◽  
Nacl Concentration

Abstract This work reports the process of sensor development, optimization, and characterization before the transition to on-body measurements can be made. Sensors using lactate oxidase as a sensing mechanism and tetrathiafulvalene as a mediator were optimized for sporting applications. Optimized sensors show linear range up to 24 mM lactate and sensitivity of 4.8 μA/mM which normalizes to 68 μA*cm−2/mM when accounting for surface area of the sensor. The optimized sensors were characterized 3 different ways: using commercially available reference and counter electrodes, using printed reference and counter electrodes, and using a printed reference electrode with no counter electrode. Sensors intended for measuring sweat must be selective in the presence of sweat constituents. Thus, in addition to traditional characterization in pH 7.0 buffer, we characterized sensor performance in solutions intended to approximate sweat. Sensor performance in pH 7.0 buffer solution was not reflective of sensor performance in artificial sweat, indicating that further characterization is necessary between sensor measurement in pH 7.0 buffer and on-body measurements. Furthermore, we performed enzyme activity measurements and sensor measurements concurrently in five different salts individually, finding that while NH4Cl and MgCl2 do not affect enzyme activity or sensor performance in physiologically relevant ranges of salt concentration, NaCl concentration or KCl concentration decreases enzyme activity and sensor current. On the other hand, CaCl2 induced a nonlinear change in sensor performance and enzyme activity with increasing salt concentration.

scholarly journals Immunoassay of muscle-specific creatine kinase with a monoclonal antibody and application to myogenesis and muscular dystrophy

1983 ◽  
Vol 213 (2) ◽  
pp. 417-425 ◽  
Author(s):  
G E Morris ◽  
L P Head
Keyword(s):  
Monoclonal Antibody ◽  
Creatine Kinase ◽  
Enzyme Activity ◽  
Total Protein ◽  
Plasma Concentrations ◽  
Thigh Muscle ◽  
Cell Protein ◽  
Enzyme Linked Immunosorbent Assay ◽  
Activity Measurements

A competition e.l.i.s.a. (enzyme-linked immunosorbent assay) is described that enables direct measurement of the muscle-specific polypeptide of chick creatine kinase (M-CK) in extracts of differentiating muscle-cell cultures and in blood plasma samples, even in the presence of embryonic, or brain-type, creatine kinase. The characteristics of the assay can be considerably improved by the use of a monoclonal antibody, CK-ART, instead of rabbit antisera, and we offer an explanation for this in terms of heterogeneity of antibody affinities in polyclonal antisera. In addition to native enzyme, the assay will measure creatine kinase unfolded and inactivated by 8 M-urea treatment. During chick muscle differentiation in vitro, M-CK increased from 7.5% of the total creatine kinase at 24h to 76.0% at 143h, in good agreement with isoenzyme separation data. As a percentage of the total cell protein, M-CK increased by 156-340-fold over the same period and constituted 0.38-0.56% of the total protein in late cultures. E.l.i.s.a. measurements on 17-20-day embryonic thigh-muscle extracts, which contain almost exclusively M-CK, agree well with enzyme activity and radioimmunoassay. M-CK constituted 0.7-1.6% of the total protein in 17-19-day embryonic thigh muscle. Plasma M-CK concentrations in normal 2-8-week-old chickens were found to be in the range 0.5-0.9 micrograms/ml. Plasma concentrations of 32-56 micrograms/ml were found in 8-week-old dystrophic chickens by both e.l.i.s.a. and enzyme-activity measurements. The results suggest that inactive or unfolded forms of M-CK do not normally exist, in any significant amounts, in cell and tissue extracts or in freshly prepared samples of plasma.

Abstract WP153: Post-Stroke Physical Exercise Improves Cognition in Middle-Aged Female Rats

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Sharnikha Saravanan ◽  
Weizhao Zhao ◽  
Kunjan R Dave ◽  
Miguel A Perez-Pinzon ◽  
Ami P Raval
Keyword(s):  
Enzyme Activity ◽  
Physical Exercise ◽  
Cognitive Decline ◽  
Fear Conditioning ◽  
Enzyme Activities ◽  
Female Rats ◽  
Male Rats ◽  
Mitochondrial Enzyme ◽  
Post Stroke ◽  
Activity Measurements

Background: A woman’s risk of a stroke increases exponentially following the onset of menopause, andpost-stroke cognitive decline is a significant consequence of stroke survivors. Our earlier study demonstrated that physical exercise (PE) reduced post-stroke brain injury and improved cognitive functions in male rats. The focus of our study is on the improvement of post-stroke cognitive function in female rats. Methods: Reproductively senescent Sprague-Dawley female rats were exposed to transient middle cerebral artery occlusion (tMCAO; 90 min) and randomly assigned to either PE or sham-PE groups. After 3-5 days, rats underwent sham-PE (0m/min speed) or PE (15m/min speed) for 30 mins either every day (continuous) or alternate day for five times on treadmill. The rats that underwent the alternate day paradigm were treated with ER-β agonist (DPN; 1mg/kg) or vehicle-DMSO immediately following PE/sham-PE sessions to determine the synergistic effect. Twenty-one days after the last PE/sham-PE, rats were tested for hippocampal-dependent contextual fear conditioning and freeze time was measured. Rat brains were processed for histology and infarct area was measured with MCID software. From a separate cohort of rat subjected to PE or sham-PE, brain tissue was harvested for various biochemical assays and mitochondrial enzyme activity measurements. Results: Post-tMCAO continuous PE did not reduce ischemic damage. However, alternate PE regimen with or without ER-β agonist reduced infract volume by 20% (p < 0.05) and 23% (p < 0.05), respectively as compared to no-PE. Similarly, alternate PE showed increased freezing on the second day of fear conditioning by 15% (p < 0.05), indicating improved spatial memory. Individual mitochondrial complex I, II, III and IV enzyme activity measurements demonstrated significant improvement in complex III-IV enzyme activities in the alternate PE treated group as compared to sham-PE. Conclusion: An alternate day PE paradigm and ER-β activation improves post-stroke mitochondrial enzyme activities and cognition in reproductively senescent female rats. Future studies delineating underlying mechanism could help identify therapies to prevent/reduce cognitive decline in menopausal female stroke patients.

Relation Between Acid Proteinase Activity and Redistribution of Nitrogen During Grain Development in Wheat

1976 ◽  
Vol 3 (6) ◽  
pp. 721 ◽  
Author(s):  
MJ Dalling ◽  
G Boland ◽  
JH Wilson
Keyword(s):  
Enzyme Activity ◽  
Nitrogen Removal ◽  
Nitrogen Loss ◽  
Proteinase Activity ◽  
Acid Proteinase ◽  
Wheat Cultivars ◽  
Grain Development ◽  
Significant Relation ◽  
Activity Measurements ◽  
Grain Nitrogen

Accumulation of grain nitrogen was studied in the wheat cultivars Argentine IX and Insignia. The pattern of nitrogen removal from several tissues of each cultivar was compared with the pattern of acid proteinase activity. There was a highly significant relation between the rate of nitrogen loss from the tissues and the rate estimated from the enzyme activity measurements. This suggests an important role for acid proteinase enzymes in leaf senescence. Redistribution of nitrogen present in the plant at anthesis accounted for 78.5 and 80.6 % of the final grain nitrogen yield of Argentine IX and Insignia respectively.

scholarly journals Fast and accurate enzyme activity measurements using a chip-based microfluidic calorimeter

2018 ◽  
Vol 544 ◽  
pp. 57-63 ◽  
Author(s):  
Morten M.C.H. van Schie ◽  
Kourosh Honarmand Ebrahimi ◽  
Wilfred R. Hagen ◽  
Peter-Leon Hagedoorn
Keyword(s):  
Enzyme Activity ◽  
Activity Measurements

Amperometric Microcell for Enzyme Activity Measurements

1998 ◽  
Vol 70 (10) ◽  
pp. 2156-2162 ◽  
Author(s):  
Geza Nagy ◽  
Clarke X. Xu ◽  
Richard P. Buck ◽  
Erno Lindner ◽  
Michael R. Neuman
Keyword(s):  
Enzyme Activity ◽  
Activity Measurements

scholarly journals Screening Cellulolytic Bacteria from the Digestive Tract Snail (Achatina fulica) and Test the Ability of Cellulase Activity

2016 ◽  
Vol 8 (3) ◽  
pp. 386
Author(s):  
Wijanarka Wijanarka ◽  
Endang Kusdiyantini ◽  
Sarjana Parman
Keyword(s):  
Enzyme Activity ◽  
Digestive Tract ◽  
Generation Time ◽  
Cellulase Activity ◽  
Biology Education ◽  
Activity Measurement ◽  
Bacterial Isolates ◽  
Achatina Fulica ◽  
Cellulolytic Bacteria ◽  
Activity Measurements

<p>On the research of enzyme production levels observed cellulase produced by bacteria in the digestive tract of the isolation of the Snail (<em>Achatina fulica</em>). Isolation of bacteria based on the ability of bacteria to grow on CMC media. The purpose of this study was to determine cellulase activity by cellulolytic bacteria. Some bacterial isolates were identified as cellulolytic bacteria, they were KE-B1, KE-B2, KE-B3, KE-B4, KE-B5, and KE-B6. Isolates KE-B6 was the best isolates. Furthermore KE-B6 isolates were grown on media production to determine the pattern of growth and enzyme activity. Measurement of cell growth was conducted by inoculating starter aged 22 hours at CMC production of liquid medium. Cellulase enzyme activity measurements was performed by the DNS method. The results showed that the highest activity by new isolate bacteria KE-B6 and its value of the activity of 0.4539 U/mL, growth rate (µ) 0.377/hour and generation time (g) 1.84 hour. This research expected cellulase of producing bacteria were easy, inexpensive and efficient. This enzyme can be used as an enzyme biolytic once expected to replace expensive commercial enzyme. The biotylic enzyme can be applied to strains improvement (protoplast fusion).</p><p><strong>How to Cite</strong></p><p>Wijanarka, W., Kusdiyantini, E. &amp; Parman, S. (2016). Screening Cellulolytic Bacteria from the Digestive Tract Snail (<em>Achatina fulica</em>) and Test the Ability of Cellulase Activity. <em>Biosaintifika: Journal of Biology &amp; Biology Education</em>, 8(3), 386-392. </p>

scholarly journals Denoting the intensity of soil biochemical transition according to stand species composition

2018 ◽  
Vol 79 (4) ◽  
pp. 327-334
Author(s):  
Grażyna Olszowska
Keyword(s):  
Enzyme Activity ◽  
European Beech ◽  
Field Work ◽  
Soil Enzyme ◽  
Soil Enzyme Activity ◽  
Soil Parameters ◽  
Silver Fir ◽  
Forest Region ◽  
Activity Measurements ◽  
Alkaline Cations

Abstract The aim of this study was to denote biochemical soil activity in pure Scots pine, Norway spruce, silver fir, European larch, European beech and oak stands as well as in mixed fir-pine, beech-pine and fir-beech forests growing on a fertile fresh mixed deciduous site. The field work was carried out in the following Forest Districts: Nowe Ramuki (Mazursko-Podlaska forest region), Płońsk, Jabłonna, Brzeziny Siedlce, Grójec (Mazowiecko-Podlaska forest region) and Skarżysko, Ostrowiec and Marcule (Małopolska forest region). In 2015–2017, sample plots were assigned and chemical as well as soil enzyme activity measurements were made in each forest stand. Samples were taken from the organic (O) and humus (A) layers and for both the acidity (in 1M KCl), content of nitrogen, carbon, sum of exchangeable alkaline cations and hydrolytic acidity were determined. The investigation of soil enzymes included the measurements of urease, asparginase, acid phosphatase and dehydrogenase activity. Coniferous trees, especially fir, spruce or larch, and mixed fir-beech and pine-beech stands were observed to have a very positive influence on the biochemical soil properties. The highest activity of dehydrogenase was observed in soils of spruce and mixed fir-beech stands, whereas it was lower in soils of beech and pine stands, and the lowest in oak stands. Oak stands were furthermore characterized by the lowest soil acidity, lowest concentration of alkaline cations, the lowest nitrogen and carbon content as well as the smallest C/N ratio. In overall, soil enzyme activity showed a significant correlation with chemical soil parameters.

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