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Background: Bipolar disorder is associated with circadian disruption and a high risk of suicidal behavior. In a previous exploratory study of patients with bipolar I disorder, we found that a history of suicide attempts was associated with differences between winter and summer levels of solar insolation. The purpose of this study was to confirm this finding using international data from 42% more collection sites and 25% more countries. Methods: Data analyzed were from 71 prior and new collection sites in 40 countries at a wide range of latitudes. The analysis included 4876 patients with bipolar I disorder, 45% more data than previously analyzed. Of the patients, 1496 (30.7%) had a history of suicide attempt. Solar insolation data, the amount of the sun’s electromagnetic energy striking the surface of the earth, was obtained for each onset location (479 locations in 64 countries). Results: This analysis confirmed the results of the exploratory study with the same best model and slightly better statistical significance. There was a significant inverse association between a history of suicide attempts and the ratio of mean winter insolation to mean summer insolation (mean winter insolation/mean summer insolation). This ratio is largest near the equator which has little change in solar insolation over the year, and smallest near the poles where the winter insolation is very small compared to the summer insolation. Other variables in the model associated with an increased risk of suicide attempts were a history of alcohol or substance abuse, female gender, and younger birth cohort. The winter/summer insolation ratio was also replaced with the ratio of minimum mean monthly insolation to the maximum mean monthly insolation to accommodate insolation patterns in the tropics, and nearly identical results were found. All estimated coefficients were significant at p < 0.01. Conclusion: A large change in solar insolation, both between winter and summer and between the minimum and maximum monthly values, may increase the risk of suicide attempts in bipolar I disorder. With frequent circadian rhythm dysfunction and suicidal behavior in bipolar disorder, greater understanding of the optimal roles of daylight and electric lighting in circadian entrainment is needed.
Archaeological evidence indicates that pig domestication had begun by ∼10,500 y before the present (BP) in the Near East, and mitochondrial DNA (mtDNA) suggests that pigs arrived in Europe alongside farmers ∼8,500 y BP. A few thousand years after the introduction of Near Eastern pigs into Europe, however, their characteristic mtDNA signature disappeared and was replaced by haplotypes associated with European wild boars. This turnover could be accounted for by substantial gene flow from local European wild boars, although it is also possible that European wild boars were domesticated independently without any genetic contribution from the Near East. To test these hypotheses, we obtained mtDNA sequences from 2,099 modern and ancient pig samples and 63 nuclear ancient genomes from Near Eastern and European pigs. Our analyses revealed that European domestic pigs dating from 7,100 to 6,000 y BP possessed both Near Eastern and European nuclear ancestry, while later pigs possessed no more than 4% Near Eastern ancestry, indicating that gene flow from European wild boars resulted in a near-complete disappearance of Near East ancestry. In addition, we demonstrate that a variant at a locus encoding black coat color likely originated in the Near East and persisted in European pigs. Altogether, our results indicate that while pigs were not independently domesticated in Europe, the vast majority of human-mediated selection over the past 5,000 y focused on the genomic fraction derived from the European wild boars, and not on the fraction that was selected by early Neolithic farmers over the first 2,500 y of the domestication process.
Unique features of a global human ectoparasite identified through sequencing of the bed bug genome
(2016)
The bed bug, Cimex lectularius, has re-established itself as a ubiquitous human ectoparasite throughout much of the world during the past two decades. This global resurgence is likely linked to increased international travel and commerce in addition to widespread insecticide resistance. Analyses of the C. lectularius sequenced genome (650 Mb) and 14,220 predicted protein-coding genes provide a comprehensive representation of genes that are linked to traumatic insemination, a reduced chemosensory repertoire of genes related to obligate hematophagy, host–symbiont interactions, and several mechanisms of insecticide resistance. In addition, we document the presence of multiple putative lateral gene transfer events. Genome sequencing and annotation establish a solid foundation for future research on mechanisms of insecticide resistance, human–bed bug and symbiont–bed bug associations, and unique features of bed bug biology that contribute to the unprecedented success of C. lectularius as a human ectoparasite.
Aims: Chronic pressure or volume overload induce concentric vs. eccentric left ventricular (LV) remodelling, respectively. Previous studies suggest that distinct signalling pathways are involved in these responses. NADPH oxidase-4 (Nox4) is a reactive oxygen species-generating enzyme that can limit detrimental cardiac remodelling in response to pressure overload. This study aimed to assess its role in volume overload-induced remodelling.
Methods and results: We compared the responses to creation of an aortocaval fistula (Shunt) to induce volume overload in Nox4-null mice (Nox4−/−) vs. wild-type (WT) littermates. Induction of Shunt resulted in a significant increase in cardiac Nox4 mRNA and protein levels in WT mice as compared to Sham controls. Nox4−/− mice developed less eccentric LV remodelling than WT mice (echocardiographic relative wall thickness: 0.30 vs. 0.27, P < 0.05), with less LV hypertrophy at organ level (increase in LV weight/tibia length ratio of 25% vs. 43%, P < 0.01) and cellular level (cardiomyocyte cross-sectional area: 323 µm2 vs. 379 μm2, P < 0.01). LV ejection fraction, foetal gene expression, interstitial fibrosis, myocardial capillary density, and levels of myocyte apoptosis after Shunt were similar in the two genotypes. Myocardial phospho-Akt levels were increased after induction of Shunt in WT mice, whereas levels decreased in Nox4−/− mice (+29% vs. −21%, P < 0.05), associated with a higher level of phosphorylation of the S6 ribosomal protein (S6) and the eIF4E-binding protein 1 (4E-BP1) in WT compared to Nox4−/− mice. We identified that Akt activation in cardiac cells is augmented by Nox4 via a Src kinase-dependent inactivation of protein phosphatase 2A.
Conclusion: Endogenous Nox4 is required for the full development of eccentric cardiac hypertrophy and remodelling during chronic volume overload. Nox4-dependent activation of Akt and its downstream targets S6 and 4E-BP1 may be involved in this effect.