Understanding the overall patterns of information flow within the brain has become a major goal of neuroscience. In the current study, we produced a first draft of the Drosophila connectome at the mesoscopic scale, reconstructed from 12,995 images of neuron projections collected in FlyCircuit (version 1.1). Neuron polarities were predicted according to morphological criteria, with nodes of the network corresponding to brain regions designated as local processing units (LPUs). The weight of each directed edge linking a pair of LPUs was determined by the number of neuron terminals that connected one LPU to the other. The resulting network showed hierarchical structure and small-world characteristics and consisted of five functional modules that corresponded to sensory modalities (olfactory, mechanoauditory, and two visual) and the pre-motor center. Rich-club organization was present in this network and involved LPUs in all sensory centers, and rich-club members formed a putative motor center of the brain. Major intra- and inter-modular loops were also identified that could play important roles for recurrent and reverberant information flow. The present analysis revealed whole-brain patterns of network structure and information flow. Additionally, we propose that the overall organizational scheme showed fundamental similarities to the network structure of the mammalian brain.
To test the Pleistocene interglacial refugia hypothesis with a high-elevation mammal, we studied the phylogeography of the mole-shrew (Anourosorex yamashinai) using partial mitochondrial cytochrome b gene sequences (737 bases). This shrew is endemic to Taiwan. It is mainly distributed in the highlands from 1000 to 2500 m in elevation. We examined 103 specimens from 24 localities in three mountain ranges of Taiwan and found 36 haplotypes. These haplotypes separated into two major phylogroups (Northern and Southern) plus a minor phylogroup (Houhuan) of only one haplotype. This demonstrated strong association with geography. The formation of these three phylogroups may be the result of interglacial refugia during the middle Pleistocene. Distinct sublineages were not found within each major phylogroup, suggesting that the populations (phylogroups) explosively expanded from the interglacial refugia of ancestral founder haplotypes. The present distribution pattern of haplotypes suggests that Mount Houhuan is an effective refugium in central Taiwan. It was not possible to specify the refugia for the Northern and Southern phylogroups.
Intermittent fasting (IF), as a dietary intervention for weight loss, takes effects primarily through increasing energy expenditure. However, whether inter‐organ systems play a key role in IF remains unclear. Here, a novel hepatokine, pregnancy zone protein (PZP) is identified, which has significant induction during the refeeding stage of IF. Further, loss of function studies and protein therapeutic experiment in mice revealed that PZP promotes diet‐induced thermogenesis through activating brown adipose tissue (BAT). Mechanistically, circulating PZP can bind to cell surface glucose‐regulated protein of 78 kDa (GRP78) to promote uncoupling protein 1 (UCP1) expression via a p38 MAPK‐ATF2 signaling pathway in BAT. These studies illuminate a systemic regulation in which the IF promotes BAT thermogenesis through the endocrinal system and provide a novel potential target for treating obesity and related disorders.
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