TY  - GEN
A1  - Paßlack, Nadine
A1  - Schmiedchen, Bettina
A1  - Raila, Jens
A1  - Schweigert, Florian J.
A1  - Stumpff, Friederike
A1  - Kohn, Barbara
A1  - Neumann, Konrad
A1  - Zentek, Jürgen
T1  - Impact of increasing dietary calcium levels on calcium excretion and vitamin D metabolites in the blood of healthy adult cats
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Background

Dietary calcium (Ca) concentrations might affect regulatory pathways within the Ca and vitamin D metabolism and consequently excretory mechanisms. Considering large variations in Ca concentrations of feline diets, the physiological impact on Ca homeostasis has not been evaluated to date. In the present study, diets with increasing concentrations of dicalcium phosphate were offered to ten healthy adult cats (Ca/phosphorus (P): 6.23/6.02, 7.77/7.56, 15.0/12.7, 19.0/17.3, 22.2/19.9, 24.3/21.6 g/kg dry matter). Each feeding period was divided into a 10-day adaptation and an 8-day sampling period in order to collect urine and faeces. On the last day of each feeding period, blood samples were taken.

Results

Urinary Ca concentrations remained unaffected, but faecal Ca concentrations increased (P < 0.001) with increasing dietary Ca levels. No effect on whole and intact parathyroid hormone levels, fibroblast growth factor 23 and calcitriol concentrations in the blood of the cats were observed. However, the calcitriol precursors 25(OH)D-2 and 25(OH)D-3, which are considered the most useful indicators for the vitamin D status, decreased with higher dietary Ca levels (P = 0.013 and P = 0.033). Increasing dietary levels of dicalcium phosphate revealed an acidifying effect on urinary fasting pH (6.02) and postprandial pH (6.01) (P < 0.001), possibly mediated by an increase of urinary phosphorus (P) concentrations (P < 0.001).

Conclusions

In conclusion, calcitriol precursors were linearly affected by increasing dietary Ca concentrations. The increase in faecal Ca excretion indicates that Ca homeostasis of cats is mainly regulated in the intestine and not by the kidneys. Long-term studies should investigate the physiological relevance of the acidifying effect observed when feeding diets high in Ca and P.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 542 
KW  - chronic kidney-disease
KW  - growth-factor 23
KW  - parathyroid-hormone
KW  - urinary ph
KW  - phosphorus
KW  - FGF23
KW  - deficiency
KW  - dogs
KW  - hypercalciuria
KW  - secretion
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-411302
SN  - 1866-8372
IS  - 542
ER  - 
TY  - GEN
A1  - Yan, Robert
A1  - Friemel, Martin
A1  - Aloisi, Claudia
A1  - Huynen, Martijn
A1  - Taylor, Ian A.
A1  - Leimkühler, Silke
A1  - Pastore, Annalisa
T1  - The eukaryotic-specific Isd11 is a complex- orphan protein with ability to bind the prokaryotic IscS
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - The eukaryotic protein Isd11 is a chaperone that binds and stabilizes the central component of the essential metabolic pathway responsible for formation of iron-sulfur clusters in mitochondria, the desulfurase Nfs1. Little is known about the exact role of Isd11. Here, we show that human Isd11 (ISD11) is a helical protein which exists in solution as an equilibrium between monomer, dimeric and tetrameric species when in the absence of human Nfs1 (NFS1). We also show that, surprisingly, recombinant ISD11 expressed in E. coli co-purifies with the bacterial orthologue of NFS1, IscS. Binding is weak but specific suggesting that, despite the absence of Isd11 sequences in bacteria, there is enough conservation between the two desulfurases to retain a similar mode of interaction. This knowledge may inform us on the conservation of the mode of binding of Isd11 to the desulfurase. We used evolutionary evidence to suggest Isd11 residues involved in the interaction.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 551 
KW  - sulfur cluster formation
KW  - Escherichia coli
KW  - cysteine desulfurase
KW  - interacting protein
KW  - bacterial frataxin
KW  - statistical-model
KW  - biogenesis
KW  - biosynthesis
KW  - NFS1
KW  - deficiency
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-411906
SN  - 1866-8372
IS  - 551
ER  -