scholarly journals Macrofauna regulate heterotrophic bacterial carbon and nitrogen incorporation in low-oxygen sediments

2012 ◽  
Vol 6 (11) ◽  
pp. 2140-2151 ◽  
Author(s):  
William R Hunter ◽  
Bart Veuger ◽  
Ursula Witte
Keyword(s):  
Low Oxygen ◽  
Carbon And Nitrogen ◽  
Nitrogen Incorporation

scholarly journals Tracing carbon and nitrogen incorporation and pathways in the microbial community of a photic subtidal sand

2008 ◽  
Vol 53 ◽  
pp. 257-269 ◽  
Author(s):  
V Evrard ◽  
PLM Cook ◽  
B Veuger ◽  
M Huettel ◽  
JJ Middelburg
Keyword(s):  
Microbial Community ◽  
Carbon And Nitrogen ◽  
Nitrogen Incorporation

The regulation of oxygen to low concentrations in marine oxygen-minimum zones

2019 ◽  
Vol 77 (3) ◽  
pp. 297-324 ◽  
Author(s):  
Don E. Canfield ◽  
Beate Kraft ◽  
Carolin R. Löscher ◽  
Richard A. Boyle ◽  
Bo Thamdrup ◽  
...  
Keyword(s):  
Bay Of Bengal ◽  
Gulf Of California ◽  
Large Scale ◽  
Global Ocean ◽  
Low Oxygen ◽  
Carbon And Nitrogen ◽  
Biogeochemical Models ◽  
Oxygen Conditions ◽  
Oxygen Cycling ◽  
Oxygen Minimum

The Bay of Bengal hosts persistent, measurable, but sub-micromolar, concentrations of oxygen in its oxygen-minimum zone (OMZ). Such low-oxygen conditions are not necessarily rare in the global ocean and seem also to characterize the OMZ of the Pescadero Basin in the Gulf of California, as well as the outer edges of otherwise anoxic OMZs, such as can be found, for example, in the Eastern Tropical North Pacific. We show here that biological controls on oxygen consumption are required to allow the semistable persistence of low-oxygen conditions in OMZ settings; otherwise, only small changes in physical mixing or rates of primary production would drive the OMZ between anoxic and oxic states with potentially large swings in oxygen concentration. We propose that two controls are active: an oxygen-dependent control on oxygen respiration and an oxygen inhibition of denitrification. These controls, working alone and together, can generate low-oxygen concentrations over a wide variability in ocean mixing parameters. More broadly, we discuss the oxygen regulation of organic matter cycling and N2 production in OMZ settings. Modern biogeochemical models of nitrogen and oxygen cycling in OMZ settings do contain some of the parameterizations that we explore here. However, these models have not been applied to understanding the persistence of low, but measurable, concentrations of oxygen in settings like the Bay of Bengal, nor have they been applied to understanding what biological/physical processes control the transition from a weakly oxygenated state to a “functionally” anoxic state with implications for nitrogen cycling. Therefore, we believe that the approach here illuminates the relationship between oxygen and the biogeochemical cycling of carbon and nitrogen in settings like the Bay of Bengal. Furthermore, we believe that our results could further inform large-scale ocean models seeking to explore how global warming might influence the spread of low-oxygen waters, influencing the cycles of oxygen, carbon, and nitrogen in OMZ settings.

scholarly journals Waterlogging effects upon the phenological phases of common bean cultivar BRSMG-Uai

2020 ◽  
Vol 44 ◽  
Author(s):  
Beatriz Gonçalves Pereira Costa ◽  
Bárbara Christina Silva Amâncio ◽  
Lissa Vasconcellos Vilas Boas ◽  
Ludmila da Silva Bastos ◽  
Debora Domiciano ◽  
...  
Keyword(s):  
Common Bean ◽  
Reductase Activity ◽  
Low Oxygen ◽  
Carbon And Nitrogen ◽  
Bean Cultivar ◽  
Common Bean Cultivar ◽  
The Common ◽  
Carbon And Nitrogen Metabolism ◽  
Growth Analyses ◽  
Phenological Phases

ABSTRACT Common bean (Phaseolus vulgaris L.) is an important source of protein and carbohydrates, besides being rich in several mineral nutrients. In a flooding situation, the low availability of oxygen may result in hypoxia or anoxia condition. Therefore, this study aimed to evaluate the responses of the common bean cultivar BRSMG-Uai subjected to hypoxia in different phenological phases, analyzing its responses in terms of growth, productivity, carbon and nitrogen metabolism. Thus, seeds of common beans were germinated and when the seedling reached growth stage V1, they were transferred to plastic boxes containing 40L of nutritive solution with steady aeration. Distinct series of plants were exposed to air-restriction on their roots for nine days, in three different phenological phases V3/V4, R6 and R7. Samples were collected for biochemical and growth analyses in a completely random design (n=6). The plants subjected to low availability of oxygen presented a reduction in bean number, displaying the greatest loss in productivity in V3/V4, conferring the highest sensitivity to hypoxia in this phase. On the other hand, there was an increase in sugar concentration in leaves, and it was also possible to observe an increase in hydrogen peroxide in leaves and roots, concomitant with a decrease in superoxide dismutase activity in all phenological phases. There was also an increase in ascorbate peroxidase activity in roots in R6, as well as in nitrate reductase activity. We conclude that the cultivar BRSMG-Uai presents sensitivity to low oxygen availability, and the phenological phaseV3/V4 is the most critical for it.

scholarly journals Regulation of Primary Metabolism in Response to Low Oxygen Availability as Revealed by Carbon and Nitrogen Isotope Redistribution

2015 ◽  
Vol 170 (1) ◽  
pp. 43-56 ◽  
Author(s):  
Carla António ◽  
Carola Päpke ◽  
Marcio Rocha ◽  
Houssein Diab ◽  
Anis M. Limami ◽  
...  
Keyword(s):  
Nitrogen Isotope ◽  
Oxygen Availability ◽  
Primary Metabolism ◽  
Low Oxygen ◽  
Carbon And Nitrogen

Metabolic signalling and the partitioning of resources in plant storage organs

1999 ◽  
Vol 133 (3) ◽  
pp. 243-249 ◽  
Author(s):  
NIGEL G. HALFORD
Keyword(s):  
Dry Weight ◽  
Wild Relatives ◽  
Crop Plants ◽  
Wild Plants ◽  
Young Plant ◽  
Carbon And Nitrogen ◽  
Cultivated Potato ◽  
Metabolic Signalling ◽  
Storage Organs ◽  
Plant Storage

The most important harvested organs of crop plants, such as seeds, tubers and fruits, are often described as assimilate sinks. They play little or no part in the fixation of carbon through the production of sugars through photosynthesis, or in the uptake of nitrogen and sulphur, but import these assimilated resources to support metabolism and to store them in the form of starch, oils and proteins. Wild plants store resources in seeds and tubers to later support an emergent young plant. Cultivated crops are effectively storing resources to provide us with food and many have been bred to accumulate much more than would be required otherwise. For example, approximately 80% of a cultivated potato plant's dry weight is contained in its tubers, ten times the proportion in the tubers of its wild relatives (Inoue & Tanaka 1978). Cultivation and breeding has brought about a shift in the partitioning of carbon and nitrogen assimilate between the organs of the plant.

Precipitation in silicon: Microanalysis

1988 ◽  
Vol 46 ◽  
pp. 474-475
Author(s):  
R.W. Carpenter
Keyword(s):  
Transition Metals ◽  
Spatial Resolution ◽  
Thin Foil ◽  
Precipitation Reaction ◽  
High Current ◽  
Reaction Products ◽  
Carbon And Nitrogen ◽  
Dielectric Layers ◽  
Precipitation Processes ◽  
Areas Of Interest

Interest in precipitation processes in silicon appears to be centered on transition metals (for intrinsic and extrinsic gettering), and oxygen and carbon in thermally aged materials, and on oxygen, carbon, and nitrogen in ion implanted materials to form buried dielectric layers. A steadily increasing number of applications of microanalysis to these problems are appearing. but still far less than the number of imaging/diffraction investigations. Microanalysis applications appear to be paced by instrumentation development. The precipitation reaction products are small and the presence of carbon is often an important consideration. Small high current probes are important and cryogenic specimen holders are required for consistent suppression of contamination buildup on specimen areas of interest. Focussed probes useful for microanalysis should be in the range of 0.1 to 1nA, and estimates of spatial resolution to be expected for thin foil specimens can be made from the curves shown in Fig. 1.

HIF1-α-Mediated Gene Expression Induced by Vitamin B1 Deficiency

2013 ◽  
Vol 83 (3) ◽  
pp. 188-197 ◽  
Author(s):  
Rebecca L. Sweet ◽  
Jason A. Zastre
Keyword(s):  
Gene Expression ◽  
Thiamine Deficiency ◽  
Glucose Transporter ◽  
Neuroblastoma Cell ◽  
Hypoxia Inducible Factor ◽  
Clinical Manifestations ◽  
Vitamin B1 ◽  
Low Oxygen ◽  
Glucose Transporter 1 ◽  
Metabolic Intermediates

It is well established that thiamine deficiency results in an excess of metabolic intermediates such as lactate and pyruvate, which is likely due to insufficient levels of cofactor for the function of thiamine-dependent enzymes. When in excess, both pyruvate and lactate can increase the stabilization of the hypoxia-inducible factor 1-alpha (HIF-1α) transcription factor, resulting in the trans-activation of HIF-1α regulated genes independent of low oxygen, termed pseudo-hypoxia. Therefore, the resulting dysfunction in cellular metabolism and accumulation of pyruvate and lactate during thiamine deficiency may facilitate a pseudo-hypoxic state. In order to investigate the possibility of a transcriptional relationship between hypoxia and thiamine deficiency, we measured alterations in metabolic intermediates, HIF-1α stabilization, and gene expression. We found an increase in intracellular pyruvate and extracellular lactate levels after thiamine deficiency exposure to the neuroblastoma cell line SK-N-BE. Similar to cells exposed to hypoxia, there was a corresponding increase in HIF-1α stabilization and activation of target gene expression during thiamine deficiency, including glucose transporter-1 (GLUT1), vascular endothelial growth factor (VEGF), and aldolase A. Both hypoxia and thiamine deficiency exposure resulted in an increase in the expression of the thiamine transporter SLC19A3. These results indicate thiamine deficiency induces HIF-1α-mediated gene expression similar to that observed in hypoxic stress, and may provide evidence for a central transcriptional response associated with the clinical manifestations of thiamine deficiency.

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