Synthesis, characterization and crystal structures of nickel complexes with dissymmetric tetradentate ligands containing a mixed-donor sphere

Four new nickel(II) complexes of dissymmetric tetradentate ligands, containing mixed-ligand donor sets of NSNS or NSNO, have been synthesized. These complexes were prepared by facile template reactions of the appropriate aldehyde and amine in the presence of [Ni(H₂O)₆](BF₄)₂, resulting directly in the desired nickel compounds. The nickel compounds were characterized by analytical, spectroscopic and electrochemical methods. The structures of [Ni(pyzs)]BF₄, [Ni(pyrs)]BF₄ and [Ni(pyzo)]BF₄ (see Scheme 1) have been determined by single-crystal X-ray crystallography, showing the geometry of the nickel ion to be square-planar. Vis–NIR spectra show that the phenolate-containing complexes [Ni(pyzo)]BF₄ and [Ni(pyro)]BF₄ (see Scheme 1) are essentially square-planar in nitromethane, but tetragonal octahedral in methanol, whereas the thiophenolate-containing compounds [Ni(pyzs)]BF₄ and [Ni(pyrs)]BF₄ remain square-planar in both solvents. Titration of the thiophenolate-containing complexes with 1-methylimidazole results in diamagnetic five-coordinated complexes. Electrochemistry shows quasi-reversible reductions to Ni(I) to occur for [Ni(pyzo)]BF₄, [Ni(pyrs)]BF₄ and [Ni(pyro)]BF₄.     

Heritability and genetic etiology of habitual physical activity: a twin study with objective measures

Twin studies with objective measurements suggest habitual physical activity (HPA) are modestly to highly heritable, depending on age. We aimed to confirm or refute this finding and identify relevant genetic variants using a candidate gene approach. HPA was measured for 14 days with a validated triaxial accelerometer (Tracmor) in two populations: (1) 28 monozygotic and 24 dizygotic same-sex twin pairs (aged 22 ± 5 years, BMI 21.8 ± 3.4 kg/m², 21 male, 31 female pairs); (2) 52 and 65 unrelated men and women (aged 21 ± 2 years, BMI 22.0 ± 2.5 kg/m²). Single nucleotide polymorphisms (SNPs) in PPARD, PPARGC1A, NRF1 and MTOR were considered candidates. Association analyses were performed for both groups separately followed by meta-analysis. Structural equation modeling shows significant familiality for HPA, consistent with a role for additive genetic factors (heritability 57 %, 95 % CI 32–74 %, AE model) or common environmental factors (47 %, 95 % CI 23–65 %, CE model). A moderate heritability was observed for the time spent on low- and high-intensity physical activity (P ≤ 0.05), but could not be confirmed for the time spent on moderate-intensity physical activity. For PPARD, each additional effect allele was inversely associated with HPA (P ≤ 0.01; rs2076168 allele C) or tended to be associated with HPA (P ≤ 0.05; rs2267668 allele G). Linkage disequilibrium existed between those two SNPs (alleles A/G and A/C, respectively) and meta-analysis showed that carriers of the AAGC haplotype were less physically active than carriers of the AAAA and AA AC haplotypes combined (P = 0.017). For PPARGC1A, carriers of AA in rs8192678 spent more time on high-intensity physical activity than GG carriers (P = 0.001). No associations were observed with SNPs in NRF1 and MTOR. In conclusion, HPA may be modestly heritable, which is confirmed by an association with variants in PPARD.     

Hypoxia-mimetic effects in the secretome of human preadipocytes and adipocytes

White adipose tissue (WAT) regulates energy metabolism by secretion of proteins with endocrine and paracrine effects. Dysregulation of the secretome of obesity-associated enlarged WAT may lead to obesity-related disorders. This can be caused by hypoxia as a result of poorly vascularized WAT. The effect of hypoxia on the secretome of human (pre)adipocytes is largely unknown. Therefore, we investigated the effect of CoCl₂, a hypoxia mimetic, on the secretome of human SGBS (pre)adipocytes by a proteomics approach combined with bioinformatic analysis. In addition, regulation of protein secretion was examined by protein turnover experiments. As such, secretome changes were particularly associated with protein down-regulation and extracellular matrix protein dysregulation. The observed up-regulation of collagens in adipocytes may be essential for cell survival while down-regulation of collagens in preadipocytes may indicate a disturbed differentiation process. These CoCl₂-induced changes reflect WAT dysfunction that ultimately may lead to obesity-associated complications. In addition, 9 novel adipocyte secreted proteins were identified from which 6 were regulated by CoCl₂. Mass spectrometry data have been deposited to the ProteomeXchange with identifier PXD000162.     

Genome sequencing reveals fine scale diversification and reticulation history during speciation in Sus

Background

Elucidating the process of speciation requires an in-depth understanding of the evolutionary history of the species in question. Studies that rely upon a limited number of genetic loci do not always reveal actual evolutionary history, and often confuse inferences related to phylogeny and speciation. Whole-genome data, however, can overcome this issue by providing a nearly unbiased window into the patterns and processes of speciation. In order to reveal the complexity of the speciation process, we sequenced and analyzed the genomes of 10 wild pigs, representing morphologically or geographically well-defined species and subspecies of the genus Sus from insular and mainland Southeast Asia, and one African common warthog.

Results

Our data highlight the importance of past cyclical climatic fluctuations in facilitating the dispersal and isolation of populations, thus leading to the diversification of suids in one of the most species-rich regions of the world. Moreover, admixture analyses revealed extensive, intra- and inter-specific gene-flow that explains previous conflicting results obtained from a limited number of loci. We show that these multiple episodes of gene-flow resulted from both natural and human-mediated dispersal.

Conclusions

Our results demonstrate the importance of past climatic fluctuations and human mediated translocations in driving and complicating the process of speciation in island Southeast Asia. This case study demonstrates that genomics is a powerful tool to decipher the evolutionary history of a genus, and reveals the complexity of the process of speciation.     

Metabolomics of prolonged fasting in humans reveals new catabolic markers

Fasting is one of the simplest metabolic challenges that can be performed in humans. We here report for the first time a comprehensive analysis of the human ??fasting metabolome?? obtained from analysis of plasma and urine samples in a small cohort of healthy volunteers, using nuclear magnetic resonance (NMR), gas chromatography- and liquid chromatography-mass spectrometry (GC-MS and LC-MS). Intra- and inter-individual variation of metabolites was on measurement of four overnight fasting samples collected from each volunteer over a four week period. One additional sample per volunteer was collected following a prolonged fasting period of 36?h. Amongst a total of 377 quantified entities in plasma around 44% were shown to change significantly in concentration when volunteers extended fasting from 12 to 36?h. In addition to known markers (plasma free fatty acids, glycerol, ketone bodies) that reflect changes in the body??s fuel management under fasting conditions a wide range of ??new?? entities such as ??-aminobutyrate as well as other amino and keto acids were identified as fasting markers. Based on multiple correlations amongst the metabolites and selected hormones in plasma such as leptin or insulin-like-growth-factor-1 (IGF-1), a robust metabolic network with coherent regulation of a wide range of metabolites could be identified. The metabolomics approach described here demonstrates the plasticity of human metabolism and identifies new and robust markers of the fasting state.     

Linking biological activity with herbal constituents by systems biology-based approaches: effects of Panax ginseng in type 2 diabetic Goto-Kakizaki rats

Although a number of animal experiments and clinical trials have investigated the effects of ginseng roots on diabetes, the relationship between their therapeutic effects on diabetes and the quality and the growth age of this herb have not yet been reported. This study systematically investigated the effects of 3- to 6-year-old ginseng roots on glycemic and plasma lipid control in a rat model of type 2 diabetes. Six groups of male Goto-Kakizaki (GK) rats received either metformin, 3- to 6-year-old ginseng roots, or no treatment. The treatments were administered twice daily for 9 weeks. A combined approach was used that involved applying liquid chromatography-mass spectrometry-based lipidomics, measuring biochemical parameters and profiling the components of ginseng roots of different ages. Compared to the untreated controls, treatment with 4- and 6-year-old ginseng roots significantly improved glucose disposal, and 5-year-old ginseng treatment significantly increased high density lipoprotein cholesterol. Treatment with 6-year-old ginseng significantly decreased total plasma triacylglyceride (TG) and very-low-density lipoprotein cholesterol and improved plasma glycated hemoglobin (HbA1c). In addition, treatment with 4- to 6-year-old ginseng influenced plasma lipidomics in diabetic GK rats by reducing TG lipid species. Metformin significantly reduced fasting blood glucose by 41% and reduced HbA1c by 11%, but showed no effects on the plasma lipid parameters. The present study demonstrates that ginseng roots show growth age-dependent therapeutic effects on hyperlipidemia and hyperglycemia in diabetic GK rats. These age-dependent effects may be linked with the variation in both the ratios and concentrations of specific bioactive ginsenosides in ginseng roots of different growth ages. This study introduced novel systems biology-based approaches for linking biological activities with potential active components in herbal mixtures.     

Local Knowledge and Conservation of Seagrasses in the Tamil Nadu State of India

Local knowledge systems are not considered in the conservation of fragile seagrass marine ecosystems. In fact, little is known about the utility of seagrasses in local coastal communities. This is intriguing given that some local communities rely on seagrasses to sustain their livelihoods and have relocated their villages to areas with a rich diversity and abundance of seagrasses. The purpose of this study is to assist in conservation efforts regarding seagrasses through identifying Traditional Ecological Knowledge (TEK) from local knowledge systems of seagrasses from 40 coastal communities along the eastern coast of India. We explore the assemblage of scientific and local traditional knowledge concerning the 1. classification of seagrasses (comparing scientific and traditional classification systems), 2. utility of seagrasses, 3. Traditional Ecological Knowledge (TEK) of seagrasses, and 4. current conservation efforts for seagrass ecosystems. Our results indicate that local knowledge systems consist of a complex classification of seagrass diversity that considers the role of seagrasses in the marine ecosystem. This fine-scaled ethno-classification gives rise to five times the number of taxa (10 species = 50 local ethnotaxa), each with a unique role in the ecosystem and utility within coastal communities, including the use of seagrasses for medicine (e.g., treatment of heart conditions, seasickness, etc.), food (nutritious seeds), fertilizer (nutrient rich biomass) and livestock feed (goats and sheep). Local communities are concerned about the loss of seagrass diversity and have considerable local knowledge that is valuable for conservation and restoration plans. This study serves as a case study example of the depth and breadth of local knowledge systems for a particular ecosystem that is in peril.     

Reduced porcine islet isolation yield in the presence of hyperemic islets

When studying histological characteristics of porcine pancreata in relation to islet isolation, a remarkably high number of hyperemic islets (HIs) was encountered. The abnormalities observed in these HIs ranged from a single dilated vessel to hemorrhages extending into the surrounding exocrine tissue. The aim of the present study was to compare pancreata with and without HI on islet isolation outcomes. This study involved a histological examination of 143 purebred (74 juvenile and 69 adult) and 47 crossbred (only juvenile) porcine pancreata. Islet isolation was performed in 48 purebred adult pigs and in 25 crossbred pigs. Tissue samples were stained with Aldehyde Fuchsine. The presence of HIs was scored semi-quantitatively (HI-, HI+). We observed HIs in 48% of the purebred and in 68% of the crossbred pigs. However, only 3.3±3.1% and 3.1±4.7% of all assessed islets was hyperemic in HI+ pancreata in purebred and crossbred pigs, respectively. In both groups, significantly higher endocrine cell mass was found in the HI+ pancreata (p<0.01). When the higher endocrine cell mass was taken into account, we found significantly lower yields in the HI+ pancreata in both purebred and crossbred pigs (p=0.03 in both groups). The presence of HIs occurs frequently in porcine donor-pancreata and is associated with reduced isolation outcomes.