Annual plants grow vegetatively at early developmental stages and then transition to the reproductive stage, followed by senescence in the same year. In contrast, after successive years of vegetative growth at early ages, woody perennial shoot meristems begin repeated transitions between vegetative and reproductive growth at sexual maturity. However, it is unknown how these repeated transitions occur without a developmental conflict between vegetative and reproductive growth. We report that functionally diverged paralogs FLOWERING LOCUS T1 (FT1) and FLOWERING LOCUS T2 (FT2), products of whole-genome duplication and homologs of Arabidopsis thaliana gene FLOWERING LOCUS T (FT), coordinate the repeated cycles of vegetative and reproductive growth in woody perennial poplar (Populus spp.). Our manipulative physiological and genetic experiments coupled with field studies, expression profiling, and network analysis reveal that reproductive onset is determined by FT1 in response to winter temperatures, whereas vegetative growth and inhibition of bud set are promoted by FT2 in response to warm temperatures and long days in the growing season. The basis for functional differentiation between FT1 and FT2 appears to be expression pattern shifts, changes in proteins, and divergence in gene regulatory networks. Thus, temporal separation of reproductive onset and vegetative growth into different seasons via FT1 and FT2 provides seasonality and demonstrates the evolution of a complex perennial adaptive trait after genome duplication.ife cycles of higher plants display a great diversity in morphological and seasonal adaptation. Annual plants grow, reproduce, and senesce within a growing season, whereas woody perennials display successive years of vegetative growth before reaching sexual maturity (1-3). After this time, shoot meristems begin cyclical transitions between vegetative and reproductive growth. Consequently, shoots may repeatedly form early vegetative buds (Vegetative Zone I), reproductive buds (Floral Zone), and late vegetative buds (Vegetative Zone II) in a sequential manner (3). However, our understanding of the mechanisms underlying such complex phenotypes, and thus variation in growth habits and adaptation, remain rudimentary. In the herbaceous perennial Arabis alpina, repeated transcriptional repression and activation of PERPETUAL FLOWERING 1 (PEP1), an ortholog of the floral repressor FLOWERING LOCUS C (FLC) in annual Arabidopsis thaliana (4), controls recurring seasonal transitions between reproductive and vegetative phases (5). However, a true functional ortholog of FLC has not been reported in trees, nor does phylogenetic analysis point to a clear structural ortholog of FLC in poplar (Populus spp.) (6).Previous results showed that FLOWERING LOCUS T1 (FT1) (7) and FLOWERING LOCUS T2 (FT2) (8) under the cauliflower mosaic virus 35S (CaMV 35S) constitutive overexpression promoter induce early flowering in poplar. Transcript abundance of both genes gradually increases in the growing season as poplar trees mature....

The functional interactions between the gut microbiota and the host are important for host physiology, homeostasis, and sustained health. We compared the skeletal muscle of germ-free mice that lacked a gut microbiota to the skeletal muscle of pathogen-free mice that had a gut microbiota. Compared to pathogen-free mouse skeletal muscle, germ-free mouse skeletal muscle showed atrophy, decreased expression of insulin-like growth factor 1, and reduced transcription of genes associated with skeletal muscle growth and mitochondrial function. Nuclear magnetic resonance spectrometry analysis of skeletal muscle, liver, and serum from germ-free mice revealed multiple changes in the amounts of amino acids, including glycine and alanine, compared to pathogen-free mice. Germ-free mice also showed reduced serum choline, the precursor of acetylcholine, the key neurotransmitter that signals between muscle and nerve at neuromuscular junctions. Reduced expression of genes encoding Rapsyn and Lrp4, two proteins important for neuromuscular junction assembly and function, was also observed in skeletal muscle from germ-free mice compared to pathogen-free mice. Transplanting the gut microbiota from pathogen-free mice into germ-free mice resulted in an increase in skeletal muscle mass, a reduction in muscle atrophy markers, improved oxidative metabolic capacity of the muscle, and elevated expression of the neuromuscular junction assembly genes Rapsyn and Lrp4. Treating germ-free mice with short-chain fatty acids (microbial metabolites) partly reversed skeletal muscle impairments. Our results suggest a role for the gut microbiota in regulating skeletal muscle mass and function in mice.

The wakes of a pair of circular cylinders are grossly unsteady when the cylinders are separated in a direction normal to the approaching flow by less than one cylinder diameter. The wakes flop randomly between two asymmetric states. The time-scale for the flopping is several orders of magnitude longer than the timescale of vortex shedding, and also several orders of magnitude longer than the timescale for instability of the separating shear layers. When a splitter plate is positioned suitably on the centreline of the cylinders, the flopping can be stopped and the flow made to assume either of the asymmetric states, or a symmetric steady state. For a range of plate positions a new, periodic oscillation occurs. Acoustic excitation can also destroy the flopping mean flow, replacing it by a symmetric flow.

We investigated the effect of curcumin on insulin resistance and glucose homeostasis in male C57BL/KsJ-db/db mice and their age-matched lean non-diabetic db/+ mice. Both db/+ and db/db mice were fed with or without curcumin (0.02%, wt/wt) for 6 wks. Curcumin significantly lowered blood glucose and HbA 1c levels, and it suppressed body weight loss in db/db mice. Curcumin improved homeostasis model assessment of insulin resistance and glucose tolerance, and elevated the plasma insulin level in db/db mice. Hepatic glucokinase activity was significantly higher in the curcumin-supplemented db/db group than in the db/db group, whereas glucose-6-phosphatase and phosphoenolpyruvate carboxykinase activities were significantly lower. In db/db mice, curcumin significantly lowered the hepatic activities of fatty acid synthase, beta-oxidation, 3-hydroxy-3-methylglutaryl coenzyme reductase, and acyl-CoA: cholesterol acyltransferase. Curcumin significantly lowered plasma free fatty acid, cholesterol, and triglyceride concentrations and increased the hepatic glycogen and skeletal muscle lipoprotein lipase in db/db mice. Curcumin normalized erythrocyte and hepatic antioxidant enzyme activities (superoxide dismutase, catalase, gluthathione peroxidase) in db/db mice that resulted in a significant reduction in lipid peroxidation. However, curcumin showed no effect on the blood glucose, plasma insulin, and glucose regulating enzyme activities in db/+ mice. These results suggest that curcumin seemed to be a potential glucose-lowering agent and antioxidant in type 2 diabetic db/db mice, but had no affect in non-diabetic db/+ mice.