TY  - JOUR
A1  - Piepho, Maike
A1  - Arts, Michael T.
A1  - Wacker, Alexander
T1  - Species-specific variation in fatty acid concentrations of four phytoplankton species does phosphorus supply influence the effect of light intensity of temperature?
JF  - Journal of phycology
N2  - We tested, in the laboratory, the influence of light intensity, temperature, and phosphorus (P) supply on fatty acid (FA) concentrations of four freshwater algae: the green algae Scenedesmus quadricauda (Turpin) Breb. and Chlamydomonas globosa J. Snow, the cryptophyte Cryptomonas ovata Ehrenb., and the diatom Cyclotella meneghiniana Kutz. We investigated the main and interactive effects of two variables on algal FA concentrations (i.e., light intensity and P supply or temperature and P supply). Interactive effects of light intensity and P supply were most pronounced in C. meneghiniana, but were also found in S. quadricauda and C. ovata. Changes in several saturated and unsaturated FA concentrations with light were more distinct in the low-P treatments than in the high-P treatments. Interactive effects of temperature and P supply on various FA concentrations were observed in all four species, but there was no consistent pattern. In lake ecosystems, P limitation often coincides with high light intensities and temperatures in summer. Therefore, it is important to examine how combinations of these environmental conditions affect FA concentrations of primary producers that are important sources of FAs for higher trophic levels.
KW  - Chlamydomonas
KW  - Cryptomonas
KW  - Cyclotella
KW  - fatty acids
KW  - light
KW  - lipids
KW  - phosphate
KW  - PUFA
KW  - Scenedesmus
KW  - temperature
Y1  - 2012
U6  - https://doi.org/10.1111/j.1529-8817.2011.01103.x
SN  - 0022-3646
VL  - 48
IS  - 1
SP  - 64
EP  - 73
PB  - Wiley-Blackwell
CY  - Malden
ER  - 
TY  - JOUR
A1  - Bär, Ludmilla
A1  - Feger, Martina
A1  - Fajol, Abul
A1  - Klotz, Lars-Oliver
A1  - Zeng, Shufei
A1  - Lang, Florian
A1  - Hocher, Berthold
A1  - Föller, Michael
T1  - Insulin suppresses the production of fibroblast growth factor 23 (FGF23)
JF  - Proceedings of the National Academy of Sciences of the United States of America
N2  - Fibroblast growth factor 23 (FGF23) is produced by bone cells and regulates renal phosphate and vitamin D metabolism, as well as causing left ventricular hypertrophy. FGF23 deficiency results in rapid aging, whereas high plasma FGF23 levels are found in several disorders, including kidney or cardiovascular diseases. Regulators of FGF23 production include parathyroid hormone (PTH), calcitriol, dietary phosphate, and inflammation. We report that insulin and insulin-like growth factor 1 (IGF1) are negative regulators of FGF23 production. In UMR106 osteoblast-like cells, insulin and IGF1 down-regulated FGF23 production by inhibiting the transcription factor forkhead box protein O1 (FOXO1) through phosphoinositide 3-kinase (PI3K)/protein kinase B (PKB)/Akt signaling. Insulin deficiency caused a surge in the serum FGF23 concentration in mice, which was reversed by administration of insulin. In women, a highly significant negative correlation between FGF23 plasma concentration and increase in plasma insulin level following an oral glucose load was found. Our results provide strong evidence that insulin/IGF1dependent PI3K/PKB/Akt/FOXO1 signaling is a powerful suppressor of FGF23 production in vitro as well as in mice and in humans.
KW  - PI3K
KW  - PKB/Akt
KW  - Klotho
KW  - phosphate
Y1  - 2018
U6  - https://doi.org/10.1073/pnas.1800160115
SN  - 0027-8424
VL  - 115
IS  - 22
SP  - 5804
EP  - 5809
PB  - National Acad. of Sciences
CY  - Washington
ER  -