scholarly journals Oxygen limitation can trigger the production of branched GDGTs in culture

2021 ◽  
pp. 36-39
Author(s):  
T.A. Halamka ◽  
J.M. McFarlin ◽  
A.D. Younkin ◽  
J. Depoy ◽  
N. Dildar ◽  
...  
Keyword(s):  
Oxygen Limitation

scholarly journals Glucose-Limited Fed-Batch Cultivation Strategy to Mimic Large-Scale Effects in Escherichia coli Linked to Accumulation of Non-Canonical Branched-Chain Amino Acids by Combination of Pyruvate Pulses and Dissolved Oxygen Limitation

2021 ◽  
Vol 9 (6) ◽  
pp. 1110
Author(s):  
Ángel Córcoles García ◽  
Peter Hauptmann ◽  
Peter Neubauer
Keyword(s):  
Amino Acids ◽  
Dissolved Oxygen ◽  
Large Scale ◽  
Scale Effects ◽  
Branched Chain Amino Acids ◽  
Oxygen Limitation ◽  
Fed Batch ◽  
Fermentation Products ◽  
Cultivation Strategy ◽  
Branched Chain

Insufficient mixing in large-scale bioreactors provokes gradient zones of substrate, dissolved oxygen (DO), pH, and other parameters. E. coli responds to a high glucose, low oxygen feeding zone with the accumulation of mixed acid fermentation products, especially formate, but also with the synthesis of non-canonical amino acids, such as norvaline, norleucine and β-methylnorleucine. These amino acids can be mis-incorporated into recombinant products, which causes a problem for pharmaceutical production whose solution is not trivial. While these effects can also be observed in scale down bioreactor systems, these are challenging to operate. Especially the high-throughput screening of clone libraries is not easy, as fed-batch cultivations would need to be controlled via repeated glucose pulses with simultaneous oxygen limitation, as has been demonstrated in well controlled robotic systems. Here we show that not only glucose pulses in combination with oxygen limitation can provoke the synthesis of these non-canonical branched-chain amino acids (ncBCAA), but also that pyruvate pulses produce the same effect. Therefore, we combined the enzyme-based glucose delivery method Enbase® in a PALL24 mini-bioreactor system and combined repeated pyruvate pulses with simultaneous reduction of the aeration rate. These cultivation conditions produced an increase in the non-canonical branched chain amino acids norvaline and norleucine in both the intracellular soluble protein and inclusion body fractions with mini-proinsulin as an example product, and this effect was verified in a 15 L stirred tank bioreactor (STR). To our opinion this cultivation strategy is easy to apply for the screening of strain libraries under standard laboratory conditions if no complex robotic and well controlled parallel cultivation devices are available.

scholarly journals Thermal performance of fish is explained by an interplay between physiology, behaviour and ecology

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Philipp Neubauer ◽  
Ken H Andersen
Keyword(s):  
Thermal Performance ◽  
Null Model ◽  
Oxygen Limitation ◽  
Driving Mechanism ◽  
Metabolic Rates ◽  
Metabolic Scope ◽  
And Function ◽  
Temperature Impacts ◽  
Term Performance ◽  
Species Ecology

Abstract Increasing temperatures under climate change are thought to affect individual physiology of fish and other ectotherms through increases in metabolic demands, leading to changes in species performance with concomitant effects on species ecology. Although intuitively appealing, the driving mechanism behind thermal performance is contested; thermal performance (e.g. growth) appears correlated with metabolic scope (i.e. oxygen availability for activity) for a number of species, but a substantial number of datasets do not support oxygen limitation of long-term performance. Whether or not oxygen limitations via the metabolic scope, or a lack thereof, have major ecological consequences remains a highly contested question. size and trait-based model of energy and oxygen budgets to determine the relative influence of metabolic rates, oxygen limitation and environmental conditions on ectotherm performance. We show that oxygen limitation is not necessary to explain performance variation with temperature. Oxygen can drastically limit performance and fitness, especially at temperature extremes, but changes in thermal performance are primarily driven by the interplay between changing metabolic rates and species ecology. Furthermore, our model reveals that fitness trends with temperature can oppose trends in growth, suggesting a potential explanation for the paradox that species often occur at lower temperatures than their growth optimum. Our model provides a mechanistic underpinning that can provide general and realistic predictions about temperature impacts on the performance of fish and other ectotherms and function as a null model for contrasting temperature impacts on species with different metabolic and ecological traits.

scholarly journals A novel Hfq-dependent sRNA that is under FNR control and is synthesized in oxygen limitation in Neisseria meningitidis

2011 ◽  
Vol 80 (2) ◽  
pp. 507-523 ◽  
Author(s):  
Laura Fantappiè ◽  
Francesca Oriente ◽  
Alessandro Muzzi ◽  
Davide Serruto ◽  
Vincenzo Scarlato ◽  
...  
Keyword(s):  
Neisseria Meningitidis ◽  
Oxygen Limitation

scholarly journals Oxygen limitation favors the production of protein with antimicrobial activity in Pseudoalteromonas sp

2012 ◽  
Vol 43 (3) ◽  
pp. 1206-1212
Author(s):  
Ruth López ◽  
Víctor Monteón ◽  
Ernesto Chan ◽  
Rubí Montejo ◽  
Manuel Chan
Keyword(s):  
Antimicrobial Activity ◽  
Oxygen Limitation

scholarly journals Is oxygen limitation in warming waters a valid mechanism to explain decreased body sizes in aquatic ectotherms?

2018 ◽  
Vol 28 (2) ◽  
pp. 64-77 ◽  
Author(s):  
Asta Audzijonyte ◽  
Diego R. Barneche ◽  
Alan R. Baudron ◽  
Jonathan Belmaker ◽  
Timothy D. Clark ◽  
...  
Keyword(s):  
Oxygen Limitation ◽  
Body Sizes

Oxygen Limitation in Land Treatment of Concentrated Wastes

1989 ◽  
Vol 6 (4) ◽  
pp. 421-433 ◽  
Author(s):  
JOSEPH S. DEVINNY ◽  
ROBERT L. ISLANDER
Keyword(s):  
Oxygen Limitation ◽  
Land Treatment
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