Forty-six of the 106 WGDs analyzed appear to be closely associated with upshifts in the rate of diversification in angiosperms. Shifts in diversification do not appear more likely than random within a four-node lag phase following a WGD; however, younger WGD events are more likely to be followed by an upshift in diversification than older WGD events.

Animal studies have shown that the brain is an insulin-responsive organ and that central nervous insulin resistance induces obesity and disturbances in glucose metabolism. In humans, insulin effects in the brain are poorly characterized. We used a magnetoencephalography approach during a two-step hyperinsulinemic euglycemic clamp to (i) assess cerebrocortical insulin effects in humans, (ii) compare these effects between 10 lean and 15 obese subjects, and (iii) test whether the insulin receptor substrate (IRS)-1 Gly972Arg polymorphism in the insulin-signaling cascade modifies these effects. Both spontaneous and stimulated (mismatch negativity) cortical activity were assessed. In lean humans, stimulated cortical activity (P ‫؍‬ 0.046) and the beta and theta band of spontaneous cortical activity (P ‫؍‬ 0.01 and 0.04) increased with insulin infusion relative to saline. In obese humans, these effects were suppressed. Moreover, the insulin effect on spontaneous cortical activity correlated negatively with body mass index and percent body fat (all r < ؊0.4; all P < 0.05) and positively with insulin sensitivity of glucose disposal (theta band, r ‫؍‬ 0.48, P ‫؍‬ 0.017). Furthermore, insulin increased spontaneous cortical activity (beta band) in carriers of wild-type IRS-1, whereas, in carriers of the 972Arg allele, this insulin effect was absent (P ‫؍‬ 0.01). We conclude that, in lean humans, insulin modulates cerebrocortical activity, and that these effects are diminished in obese individuals. Moreover, cerebrocortical insulin resistance is found in individuals with the Gly972Arg polymorphism in IRS-1, which is considered a type 2 diabetes risk gene.glucose metabolism ͉ insulin resistance ͉ magnetoencephalography ͉ mismatch negativity ͉ type 2 diabetes T he human brain has been traditionally regarded as an insulininsensitive organ. However, there is now growing evidence that insulin signaling might be an important modulator of several functions of the brain. The insulin receptor and other components of the insulin-signaling chain, such as the insulin receptor substrate (IRS)-1 are ubiquitously expressed throughout the brain in animals and humans with particularly high concentrations in the hypothalamus, the hippocampus, and the cerebral cortex (1-3). Early work in animals suggested that insulin acts in the CNS and controls food intake and body weight (4). Furthermore, it was clearly shown that insulin crosses the blood-brain barrier (5) and, when given directly to the brain, suppresses food intake (6, 7) and mediates peripheral metabolic effects (8). Most important for the understanding of central nervous insulin function was the observation that brainspecific deletion of the insulin receptor in mice resulted in hyperphagia, obesity, and metabolic insulin resistance (9).In mice, insulin effects have been intensively studied in the hypothalamus. However, it is noteworthy that insulin receptors are also abundant in the cerebral cortex (2). Furthermore, intracerebroventricular insulin administration was associated with imp...

We present a new tribal classification, including one new tribe, Neospartoneae trib. nov., to accommodate three small genera of Argentine species (Diostea, Neosparton, and Lampaya). Phylogenetic inference suggests a South American origin for Verbenaceae, with approximately six colonization events having given rise to the Old World species.

Polyploid speciation entails substantial and rapid postzygotic reproductive isolation of nascent species that are initially sympatric with one or both parents. Despite strong postzygotic isolation, ecological niche differentiation has long been thought to be important for polyploid success. Using biogeographic data from across vascular plants, we tested whether the climatic niches of polyploid species are more differentiated than their diploid relatives and if the climatic niches of polyploid species differentiated faster than those of related diploids. We found that polyploids are often more climatically differentiated from their diploid parents than the diploids are from each other. Consistent with this pattern, we estimated that polyploid species generally have higher rates of multivariate niche differentiation than their diploid relatives. In contrast to recent analyses, our results confirm that ecological niche differentiation is an important component of polyploid speciation and that niche differentiation is often significantly faster in polyploids.