scholarly journals Signs of life: Oxygen sensors confirm viability, measure oxygen consumption and provide rapid, effective contamination monitoring for field‐based tissue culture.

2021 ◽  
Author(s):  
Kelly J. Robinson ◽  
Holly C. Armstrong ◽  
Simon E.W. Moss ◽  
Laura Oller ◽  
Ailsa J. Hall ◽  
...  
Keyword(s):  
Tissue Culture ◽  
Oxygen Consumption ◽  
Oxygen Sensors ◽  
Measure Oxygen Consumption

scholarly journals Necrostatin-1 Supplementation to Islet Tissue Culture Enhances the In-Vitro Development and Graft Function of Young Porcine Islets

2021 ◽  
Vol 22 (16) ◽  
pp. 8367
Author(s):  
Hien Lau ◽  
Shiri Li ◽  
Nicole Corrales ◽  
Samuel Rodriguez ◽  
Mohammadreza Mohammadi ◽  
...  
Keyword(s):  
Tissue Culture ◽  
Oxygen Consumption ◽  
Insulin Secretion ◽  
Oxygen Consumption Rate ◽  
Consumption Rate ◽  
In Vitro Development ◽  
Porcine Islets ◽  
Vitro Development

Pre-weaned porcine islets (PPIs) represent an unlimited source for islet transplantation but are functionally immature. We previously showed that necrostatin-1 (Nec-1) immediately after islet isolation enhanced the in vitro development of PPIs. Here, we examined the impact of Nec-1 on the in vivo function of PPIs after transplantation in diabetic mice. PPIs were isolated from pancreata of 8–15-day-old, pre-weaned pigs and cultured in media alone, or supplemented with Nec-1 (100 µM) on day 0 or on day 3 of culture (n = 5 for each group). On day 7, islet recovery, viability, oxygen consumption rate, insulin content, cellular composition, insulin secretion capacity, and transplant outcomes were evaluated. While islet viability and oxygen consumption rate remained high throughout 7-day tissue culture, Nec-1 supplementation on day 3 significantly improved islet recovery, insulin content, endocrine composition, GLUT2 expression, differentiation potential, proliferation capacity of endocrine cells, and insulin secretion. Adding Nec-1 on day 3 of tissue culture enhanced the islet recovery, proportion of delta cells, beta-cell differentiation and proliferation, and stimulation index. In vivo, this leads to shorter times to normoglycemia, better glycemic control, and higher circulating insulin. Our findings identify the novel time-dependent effects of Nec-1 supplementation on porcine islet quantity and quality prior to transplantation.

scholarly journals Studies on the activity of the hypoxia-inducible-factor hydroxylases using an oxygen consumption assay

2006 ◽  
Vol 401 (1) ◽  
pp. 227-234 ◽  
Author(s):  
Dominic Ehrismann ◽  
Emily Flashman ◽  
David N. Genn ◽  
Nicolas Mathioudakis ◽  
Kirsty S. Hewitson ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Recombinant Protein ◽  
Synthetic Peptides ◽  
Hypoxia Inducible Factor ◽  
Oxygen Sensors ◽  
Hydroxylase Activity ◽  
Protein Substrates ◽  
Physiological Conditions ◽  
The Relationship

The activity and levels of the metazoan HIF (hypoxia-inducible factor) are regulated by its hydroxylation, catalysed by 2OG (2-oxoglutarate)- and Fe(II)-dependent dioxygenases. An oxygen consumption assay was developed and used to study the relationship between HIF hydroxylase activity and oxygen concentration for recombinant forms of two human HIF hydroxylases, PHD2 (prolyl hydroxylase domain-containing protein 2) and FIH (factor inhibiting HIF), and compared with two other 2OG-dependent dioxygenases. Although there are caveats on the absolute values, the apparent Km (oxygen) values for PHD2 and FIH were within the range observed for other 2OG oxygenases. Recombinant protein substrates were found to have lower apparent Km (oxygen) values compared with shorter synthetic peptides of HIF. The analyses also suggest that human PHD2 is selective for fragments of the C-terminal over the N-terminal oxygen-dependent degradation domain of HIF-1α. The present results, albeit obtained under non-physiological conditions, imply that the apparent Km (oxygen) values of the HIF hydroxylases enable them to act as oxygen sensors providing their in vivo capacity is appropriately matched to a hydroxylation-sensitive signalling pathway.

Oxygen requirements of the dyskinetic myocardial segment

1989 ◽  
Vol 257 (4) ◽  
pp. H1184-H1191 ◽  
Author(s):  
P. A. Gayheart ◽  
J. Vinten-Johansen ◽  
W. E. Johnston ◽  
T. O. Hester ◽  
A. R. Cordell
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Coronary Arteries ◽  
Dose Response ◽  
Contractile Function ◽  
Myocardial Segment ◽  
Response Curves ◽  
Intracoronary Infusion ◽  
Oxygen Requirements ◽  
Measure Oxygen Consumption

Oxygen requirements of a noncontracting myocardial segment subjected to passive systolic stretch (dyskinesis) have not been well described. The purpose of this study was to measure oxygen consumption (MVO2) of a myocardial segment made dyskinetic by intracoronary infusion of lidocaine. In 12 anesthetized open-chest dogs, segmental shortening was measured sonomicrometrically in regions perfused by the left anterior descending (LAD) and circumflex (Cfx) coronary arteries. MVO2 was measured by arterial-venous oxygen content differences and transmural blood flow. Dose-response curves to intracoronary lidocaine showed that complete dyskinesis was achieved by a 0.25-mg/ml dose of lidocaine, whereas the Cfx region maintained a constant level of segmental shortening. MVO2 of the LAD segment was similar to that of the Cfx segment under control conditions. With lidocaine-induced dyskinesis, MVO2 in the arrested segment was reduced by 33% (P less than 0.05), despite the loss of contractile function. When bulging was prevented by ventricular unloading, MVO2 in the arrested segment decreased to 2.65 ml O2.min-1.100 g-1 (i.e., basal oxygen requirements). In conclusion, MVO2 in a pharmacologically arrested myocardial segment undergoing systolic bulging is paradoxically high relative to both basal requirements and MVO2 in the normally contracting segment.

scholarly journals Use of Water-Soluble Oxygen Sensors to Study the Oxygen Consumption during Photosensitization with Hypericin in Vitro and in Vivo

2016 ◽  
Vol 110 (3) ◽  
pp. 507a-508a
Author(s):  
Veronika Huntosova ◽  
Dominik Belej ◽  
Emmanuel Gerelli ◽  
Pavol Miskovsky ◽  
Georges Wagnieres
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Sensors ◽  
Water Soluble ◽  
Soluble Oxygen

Physical and Chemical Characteristics of Cultus Lake, British Columbia.

1937 ◽  
Vol 3 (4) ◽  
pp. 363-402 ◽  
Author(s):  
William E. Ricker
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Content ◽  
Heat Budget ◽  
Clear Lake ◽  
Equable Climate ◽  
Low Degree ◽  
Seasonal Circulation ◽  
Measure Oxygen Consumption ◽  
Physical And Chemical

Cultus lake is a rather small, fairly deep, clear lake of the western Cascade mountains, and is the home of one of the populations of Fraser river sockeye. The equable climate of the region is reflected in the low annual heat budget of the lake and its normal lack of an ice cover in winter, with continued complete or partial circulation of its water throughout that season. Judged by the low degree of hypolimnial oxygen consumption in summer, the lake is to be classed as distinctly oligotrophic. The oxygen content at all depths and seasons is sufficient for the respiration of salmonoid fishes. The water is moderately hard and slightly alkaline. Quantities of dissolved nitrates and phosphates in the water appear to be of the order characteristic of oligotrophic lakes. Silicates are present much in excess of the requirements of the lake's diatom populations. The number of adult sockeye returning to the lake in normal years is insufficient to add to its supply of nutritive salts in significant amount. Temperature observations and oxygen determinations, taken at frequent intervals for several years, have contributed to the knowledge of certain questions of general limnological interest. Such include (1) the manner in which the hypolimnion of a lake is warmed in summer; (2) the classification of the seasonal circulation periods in temperate lakes; and (3) the oxygen content of a lake at the close of vernal circulation, and its use as a standard from which to measure oxygen consumption throughout the summer.

scholarly journals Coulometric measurement of oxygen consumption during development of marine invertebrate embryos and larvae

1995 ◽  
Vol 198 (1) ◽  
pp. 19-30 ◽  
Author(s):  
O Hoegh-Guldberg ◽  
D Manahan
Keyword(s):  
Oxygen Consumption ◽  
Metabolic Rate ◽  
Energy Use ◽  
Oxygen Sensor ◽  
Marine Invertebrate ◽  
Measurement Techniques ◽  
Larval Growth ◽  
Oxygen Sensors ◽  
Single Individual ◽  
Metabolic Rates

Determining the metabolic rate of larval invertebrates from aquatic habitats is complicated by the problems of small size and the scarcity of suitable measurement techniques. In this study, coulometric respirometry (a new technique for the study of marine embryos and larvae) was used to explore several issues associated with the rate of energy use during embryonic and larval development of marine invertebrates from three phyla. Coulometric respirometry measures rates of oxygen consumption under normoxic conditions by electrochemically replacing the oxygen consumed by organisms during an experiment. This technique is based on the assumption that all electrons consumed by the anodic reactions result in the production of oxygen. We verify this assumption using direct measurements of oxygen production and show that the technique is sensitive enough (1 nmol O2 h-1) to quantify the oxygen consumption of a single individual swimming freely in a relatively large volume (2 ml). Continuous measurements can span days, and embryos in the coulometric respiration chambers develop to the larval stage at normal rates of differentiation. Measurements of metabolic rates were made with the coulometric respirometer during the complete life-span of larvae of three species (asteroid, Asterina miniata; bivalve, Crassostrea gigas; echinoid, Dendraster excentricus). For these species, metabolic power equations had mass exponents near unity (0.9­1.1), showing that metabolic rate scales isometrically with mass during larval growth. Metabolic rates were independent of the concentration of larvae used in the respirometer chambers for a range of larval concentrations from 4 to 400 larvae ml-1 (coulometric respirometer) and from 241 to 809 larvae ml-1 (polarographic oxygen sensor). Metabolic rates were measured using coulometric respirometry and two other commonly used techniques, polarographic oxygen sensors and Winkler's titration. Polarographic oxygen sensors in small, sealed chambers (100 µl) consistently gave the lowest values (by as much as 80 %) for the asteroid, echinoid and molluscan larvae. By comparison, rates of oxygen consumption measured using coulometric respirometry and Winkler's titration (to measure the change in oxygen concentration over time) were similar and consistently higher. Although the polarographic oxygen sensor is the most widely used method for measuring the metabolism of small animals in sealed 100­1000 µl chambers, it appears that the metabolism of some larvae is adversely affected by the conditions within these respirometers.

scholarly journals Growth of Spiny Lobster Panulirus homarus Fed with Moist Diet

2018 ◽  
Vol 3 (2) ◽  
pp. 95
Author(s):  
Asep Ridwanudin ◽  
Varian Fahmi ◽  
Idham Sumarto Pratama
Keyword(s):  
Oxygen Consumption ◽  
Dissolved Oxygen ◽  
Spiny Lobster ◽  
Growth And Survival ◽  
Oxygen Levels ◽  
Hypoxic Conditions ◽  
National University ◽  
Oxygen Conditions ◽  
Measure Oxygen Consumption

Oxygen is a vital parameter in aquaculture activities. The decrease of dissolved oxygen levels in aquaculture media should be highly observed, since very low dissolved oxygen conditions (hypoxia) could negatively affect to the growth and survival of fish. Therefore, research on the condition of hypoxia is very important to be studied. This study was conducted in January-February 2013 at the Laboratorium of Fish Reproductive Physiology, Pukyong National University, South Korea to measure oxygen consumption in tilapia Oreochromis niloticus (total length: 14.2 ± 1.4 cm, weight: 31.3 ± 2.0 g) under normal conditions (normoxia) and hypoxia. Measurement was conducted using respirometer (dimension: 20 × 17,5 × 10 cm; volume: 3,5 L) every 10 minutes during four hours of observation. Experiment was conducted with three replications. The results showed that oxygen consumption of tilapia fingerlings in hypoxia conditions (12.09 ± 3.20 mg O2/kg/h) was lower than normoxia (35.67 ± 4.19 mg O2/kg/h) (P<0.01). Continuous hypoxic conditions could negatively affect fish movements, which could ultimately lead to mortality when dissolved oxygen levels are very low. Meanwhile, the results on determination of critical oxygen levels for tilapia showed a dissolved oxygen range of 1.9 ± 0.5 mg/L

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