scholarly journals Effect of diatom nutrient limitation on copepod development: the role of essential lipids

2005 ◽  
Vol 291 ◽  
pp. 125-133 ◽  
Author(s):  
WCM Klein Breteler ◽  
N Schogt ◽  
S Rampen
Keyword(s):  
Nutrient Limitation ◽  
Copepod Development

Regulatory role of death specific protein in response to nutrient limitation in a marine diatom

2021 ◽  
Vol 58 ◽  
pp. 102392
Author(s):  
Ting-Bin Hao ◽  
Srinivasan Balamurugan ◽  
Wei-Dong Yang ◽  
Xiang Wang ◽  
Hong-Ye Li
Keyword(s):  
Nutrient Limitation ◽  
Specific Protein ◽  
Marine Diatom ◽  
Regulatory Role

N and P limitation shapes plant-AMF interactions across an aridity gradient

2020 ◽  
Author(s):  
Svenja Stock ◽  
Moritz Köster ◽  
Jens Boy ◽  
Roberto Godoy ◽  
Francisco Nájera ◽  
...  
Keyword(s):  
Nutrient Limitation ◽  
Drought Resistance ◽  
Plant Nutrition ◽  
Water Shortage ◽  
Aridity Gradient ◽  
P Limitation ◽  
Mediterranean Conditions ◽  
Mediterranean Woodland ◽  
Semiarid Conditions

<p>Arbuscular mycorrhizal fungi (AMF) are important partners in plant nutrition, as they increase the range to scavenge for nutrients and can access resources otherwise occlude for plants. Under water shortage, when mobility of nutrients in soil is limited, AMF are especially important to acquire resources and can modulate plant drought resistance. Strategies of plants to cope with water and nutrient restrictions are shaped by the intensity of aridity. To investigate the effect of aridity on plant-AMF associations regarding drought resistance and plant nutrient acquisition, a <sup>13</sup>CO<sub>2</sub> pulse labeling was conducted across an aridity gradient. In a semiarid shrubland (66 mm a<sup>-1</sup>), a Mediterranean woodland (367 mm a<sup>-1</sup>), and a humid temperate forest (1500 mm a<sup>-1</sup>), root and soil samples were taken from 0-10 cm and 20-30 cm soil depth before labeling and at 1 day, 3 days, and 14 days after labeling. Carbon (C), nitrogen (N), and phosphorus (P) stocks as well as AMF root colonization, extraradical AMF biomass (phospho- and neutral lipid fatty acids (PLFA and NLFA) 16:1w5c), specific root length (SRL), and root tissue density (RTD) were measured. Plant C investment into AMF and roots was determined by the <sup>13</sup>C incorporation in 16:1w5c (PLFA and NLFA) and root tissue, respectively. Soil C:N:P stoichiometry indicated a N and P limitation under humid conditions and a P limitation in the topsoil under Mediterranean conditions. N stocks were highest in the Mediterranean woodland. A strong correlation of the AMF storage compound NLFA 16:1w5c to C:P ratio under semiarid conditions pointed to a P limitation of AMF, likely resulting from low P mobility in dry and alkaline soils. With increasing aridity, the AMF abundance in root (and soil) decreased from 45% to 20% root area. <sup>13</sup>C incorporation in PLFA 16:1w5c was similar across sites, while relative AMF abundance in topsoil (PLFA 16:1w5c:SOC) was slightly higher under semiarid and humid than under Mediterranean conditions, pointing to the importance of AMF for plant nutrition under nutrient limitation. Additionally, PLFA 16:1w5c contents in soil were higher with lower P availability in each site, underlining the role of AMF to supply P for plants under P deficiency. Under humid conditions (with strong N and P limitation) and semiarid conditions (with strong water limitation), root AMF colonization increased with lower N availability, displaying the role of AMF for plant N nutrition under nutrient and/or water shortage. Under humid and Mediterranean conditions, SRL decreased (0.5 and 0.3 times, respectively) and RTD increased (1.9 and 1.7 times, respectively) with depth, indicating a drought tolerance strategy of plants to sustain water shortage. Under semiarid conditions, SRL increased with depth (2.3 times), while RTD was consistently high, suggesting an increasing proportion of long-living fine roots with depth as scavenging agents for water. These relations point to a drought avoidance strategy of plants as adaptation to long-term water limitation. Under strong nutrient limitation, as under humid and semiarid conditions, AMF are crucial to sustain plant nutrition and to enhance plant resistance to water shortage.</p>

scholarly journals The FOX transcription factor Hcm1 regulates oxidative metabolism in response to early nutrient limitation in yeast. Role of Snf1 and Tor1/Sch9 kinases

2013 ◽  
Vol 1833 (8) ◽  
pp. 2004-2015 ◽  
Author(s):  
María José Rodríguez-Colman ◽  
M. Alba Sorolla ◽  
Núria Vall-llaura ◽  
Jordi Tamarit ◽  
Joaquim Ros ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Nutrient Limitation ◽  
Oxidative Metabolism

scholarly journals The role of phosphorus dynamics in tropical forests – a modeling study using CLM-CNP

2013 ◽  
Vol 10 (8) ◽  
pp. 14439-14473 ◽  
Author(s):  
X. Yang ◽  
P. E. Thornton ◽  
D. M. Ricciuto ◽  
W. M. Post
Keyword(s):  
Nutrient Limitation ◽  
Tropical Forests ◽  
Elevated Co2 ◽  
Field Experiments ◽  
Global Climate ◽  
P Availability ◽  
Tropical Ecosystems ◽  
Model Simulations ◽  
P Limitation

Abstract. Tropical forests play a significant role in the global carbon cycle and global climate. However, tropical carbon cycling and the feedbacks from tropical ecosystems to the climate system remain critical uncertainties in current generation carbon-climate models. One of the major uncertainties comes from the lack of representation of phosphorus (P), the most limiting nutrient in tropical regions. Here we introduce P dynamics and C–N–P interactions into the CLM4-CN model and investigate the role of P cycling in controlling the productivity of tropical ecosystems. The newly developed CLM-CNP model includes all major biological and geochemical processes controlling P availability in soils and the interactions between C, N, and P cycles. Model simulations at sites along a Hawaiian soil chronosequence indicate that the introduction of P limitation greatly improved the model performance at the P-limited site. The model is also able to capture the shift in nutrient limitation along this chronosequence (from N limited to P limited), as shown in the comparison of model simulated plant responses to fertilization with the observed data. Model simulations at Amazonian forest sites show that CLM-CNP is capable of capturing the overall trend in NPP along the P availability gradient. This comparison also suggests a significant interaction between nutrient limitation and land use history. Model experiments under elevated atmospheric CO2 ([CO2]) condition suggest that tropical forest responses to increasing [CO2] will interact strongly with changes in the P cycle. We highlight the importance of two feedback pathways (biochemical mineralization and desorption of secondary mineral P) that can significantly affect P availability and determine the extent of P limitation in tropical forests under elevated [CO2]. Field experiments with elevated CO2 are therefore needed to help quantify these important feedbacks. Predictive modeling of C–P interactions will have important implications for the prediction of future carbon uptake and storage in tropical ecosystems and global climate change.

scholarly journals Disintegration of Staphylococcus epidermidis Biofilms under Glucose-Limiting Conditions Depends on the Activity of the Alternative Sigma Factor σB

2005 ◽  
Vol 71 (9) ◽  
pp. 5577-5581 ◽  
Author(s):  
Sebastian Jäger ◽  
Dietrich Mack ◽  
Holger Rohde ◽  
Matthias A. Horstkotte ◽  
Johannes K.-M. Knobloch
Keyword(s):  
Energy Storage ◽  
Nutrient Limitation ◽  
Staphylococcus Epidermidis ◽  
Sigma Factor ◽  
Alternative Sigma Factor ◽  
Polysaccharide Intercellular Adhesin ◽  
Slow Decay ◽  
The Stability

ABSTRACT To evaluate the role of the polysaccharide intercellular adhesin as an energy-storage molecule, we investigated the effect of nutrient limitation on S. epidermidis biofilms. The stability of established biofilms depends on σB activity; however, the slow decay of biofilms under conditions of nutrient limitation reveal its use as an energy-storage molecule to be unlikely.

scholarly journals Interactions between DksA and Stress-Responsive Alternative Sigma Factors Control Inorganic Polyphosphate Accumulation in Escherichia coli

2020 ◽  
Vol 202 (14) ◽  
Author(s):  
Michael J. Gray
Keyword(s):  
Escherichia Coli ◽  
Rna Polymerase ◽  
Nutrient Limitation ◽  
Protein Function ◽  
Regulatory Protein ◽  
Sigma Factors ◽  
Inorganic Polyphosphate ◽  
Content Type ◽  
Alternative Sigma Factors

ABSTRACT Bacteria synthesize inorganic polyphosphate (polyP) in response to a variety of different stress conditions. polyP protects bacteria by acting as a protein-stabilizing chaperone, metal chelator, or regulator of protein function, among other mechanisms. However, little is known about how stress signals are transmitted in the cell to lead to increased polyP accumulation. Previous work in the model enterobacterium Escherichia coli has indicated that the RNA polymerase-binding regulatory protein DksA is required for polyP synthesis in response to nutrient limitation stress. In this work, I set out to characterize the role of DksA in polyP regulation in more detail. I found that overexpression of DksA increases cellular polyP content (explaining the long-mysterious phenotype of dksA overexpression rescuing growth of a dnaK mutant at high temperatures) and characterized the roles of known functional residues of DksA in this process, finding that binding to RNA polymerase is required but that none of the other functions of DksA appear to be necessary. Transcriptomics revealed genome-wide transcriptional changes upon nutrient limitation, many of which were affected by DksA, and follow-up experiments identified complex interactions between DksA and the stress-sensing alternative sigma factors FliA, RpoN, and RpoE that impact polyP production, indicating that regulation of polyP synthesis is deeply entwined in the multifactorial stress response network of E. coli. IMPORTANCE Inorganic polyphosphate (polyP) is an evolutionarily ancient, widely conserved biopolymer required for stress resistance and pathogenesis in diverse bacteria, but we do not understand how its synthesis is regulated. In this work, I gained new insights into this process by characterizing the role of the transcriptional regulator DksA in polyP regulation in Escherichia coli and identifying previously unknown links between polyP synthesis and the stress-responsive alternative sigma factors FliA, RpoN, and RpoE.

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