Project description:Montagud2010 - Genome-scale metabolic network
of Synechocystis sp. PCC6803 (iSyn669)
This model is described in the article:
Reconstruction and analysis
of genome-scale metabolic model of a photosynthetic
bacterium.
Montagud A, Navarro E,
Fernández de Córdoba P, Urchueguía JF, Patil
KR.
BMC Syst Biol 2010; 4: 156
Abstract:
BACKGROUND: Synechocystis sp. PCC6803 is a cyanobacterium
considered as a candidate photo-biological production
platform--an attractive cell factory capable of using CO2 and
light as carbon and energy source, respectively. In order to
enable efficient use of metabolic potential of Synechocystis
sp. PCC6803, it is of importance to develop tools for
uncovering stoichiometric and regulatory principles in the
Synechocystis metabolic network. RESULTS: We report the most
comprehensive metabolic model of Synechocystis sp. PCC6803
available, iSyn669, which includes 882 reactions, associated
with 669 genes, and 790 metabolites. The model includes a
detailed biomass equation which encompasses elementary building
blocks that are needed for cell growth, as well as a detailed
stoichiometric representation of photosynthesis. We demonstrate
applicability of iSyn669 for stoichiometric analysis by
simulating three physiologically relevant growth conditions of
Synechocystis sp. PCC6803, and through in silico metabolic
engineering simulations that allowed identification of a set of
gene knock-out candidates towards enhanced succinate
production. Gene essentiality and hydrogen production potential
have also been assessed. Furthermore, iSyn669 was used as a
transcriptomic data integration scaffold and thereby we found
metabolic hot-spots around which gene regulation is dominant
during light-shifting growth regimes. CONCLUSIONS: iSyn669
provides a platform for facilitating the development of
cyanobacteria as microbial cell factories.
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Project description:Vitamin B12 is emerging as a potential therapeutic agent for diabetes-associated complications, with roles in redox balance, methylation, and mitochondrial function. Recent evidence suggests that B12 may also regulate circadian rhythms, which are closely linked to metabolic health. However, the connection between B12, circadian regulation, and protection against early diabetic liver and kidney damage remains unclear. Diabetic (Elmo1H/HIns2Akita/+) and non-diabetic (Elmo1HH) mice were treated with or without Vitamin B12 (10 mg/kg/day) in drinking water for 8 weeks, starting at 8 weeks of age. At 16 weeks, blood, liver, and kidney samples were collected for biochemical, transcriptomic, and histological analysis. Vitamin B12 significantly reduced serum triglycerides, improved mesangial expansion in kidneys, and improved liver cellular structure in diabetic mice. B12 also modulated circadian gene expression, downregulating Clock, Bmal1, and Npas2 (40–50%) while upregulating Cry1/2, Per1–3, Nr1d2, and Dbp in both liver and kidney (130–180%), regardless of diabetic status. Importantly, B12 significantly increased Nampt expression in the liver (p = 0.0062) and kidney (p = 0.0013) of diabetic mice, suggesting enhancement of the NAMPT–NAD⁺–SIRT1 axis, a key pathway for mitochondrial redox control and circadian stability. Additionally, B12 upregulated several solute carrier (SLC) transporters involved in nutrient and ion homeostasis. Together, these findings indicate that Vitamin B12 offers early protective effects against diabetic complications by improving metabolic balance and enhancing Nampt expression, supporting its potential role in preventing liver and kidney damage via circadian and NAD⁺-dependent mechanisms.
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