182 research outputs found
Disturbance indicator values for European plants
Motivation Indicator values are numerical values used to characterize the ecological niches of species and to estimate their occurrence along gradients. Indicator values on climatic and edaphic niches of plant species have received considerable attention in ecological research, whereas data on the optimal positioning of species along disturbance gradients are less developed. Here, we present a new data set of disturbance indicator values identifying optima along gradients of natural and anthropogenic disturbance for 6382 vascular plant species based on the analysis of 736,366 European vegetation plots and using expert-based characterization of disturbance regimes in 236 habitat types. The indicator values presented here are crucial for integrating disturbance niche optima into large-scale vegetation analyses and macroecological studies. Main types of variables contained We set up five main continuous indicator values for European vascular plants: disturbance severity, disturbance frequency, mowing frequency, grazing pressure and soil disturbance. The first two indicators are provided separately for the whole community and for the herb layer. We calculated the values as the average of expert-based estimates of disturbance values in all habitat types where a species occurs, weighted by the number of plots in which the species occurs within a given habitat type. Spatial location and grain Europe. Vegetation plots ranging in size from 1 to 1000 m(2). Time period and grain Vegetation plots mostly sampled between 1956 and 2013 (= 5th and 95th quantiles of the sampling year, respectively). Major taxa and level of measurement Species-level indicator values for vascular plants. Software format csv file
Post Genome-Wide Association Studies of Novel Genes Associated with Type 2 Diabetes Show Gene-Gene Interaction and High Predictive Value
Recently, several Genome Wide Association (GWA) studies in populations of European descent have identified and validated novel single nucleotide polymorphisms (SNPs), highly associated with type 2 diabetes (T2D). Our aims were to validate these markers in other European and non-European populations, then to assess their combined effect in a large French study comparing T2D and normal glucose tolerant (NGT) individuals. rs7903146 SNP, were combined (8.68-fold for the 14% of French individuals carrying 18 to 30 risk alleles with an allelic OR of 1.24). With an area under the ROC curve of 0.86, only 15 novel loci were necessary to discriminate French individuals susceptible to develop T2D. strongly associate with T2D in French individuals, and mostly in populations of Central European descent but not in Moroccan subjects. Genes expressed in the pancreas interact together and their combined effect dramatically increases the risk for T2D, opening avenues for the development of genetic prediction tests
Mitochondrial Haplogroups and Control Region Polymorphisms in Age-Related Macular Degeneration: A Case-Control Study
Background: Onset and development of the multifactorial disease age-related macular degeneration (AMD) are highly interrelated with mitochondrial functions such as energy production and free radical turnover. Mitochondrial dysfunction and overproduction of reactive oxygen species may contribute to destruction of the retinal pigment epithelium, retinal atrophy and choroidal neovascularization, leading to AMD. Consequently, polymorphisms of the mitochondrial genome (mtDNA) are postulated to be susceptibility factors for this disease. Previous studies from Australia and the United States detected associations of mitochondrial haplogroups with AMD. The aim of the present study was to test these associations in Middle European Caucasians. Methodology/Principal Findings: Mitochondrial haplogroups (combinations of mtDNA polymorphisms) and mitochondrial CR polymorphisms were analyzed in 200 patients with wet AMD (choroidal neovascularization, CNV), in 66 patients with dry AMD, and in 385 controls from Austria by means of multiplex primer extension analysis and sequencing, respectively. In patients with CNV, haplogroup H was found to be significantly less frequent compared to controls, and haplogroup J showed a trend toward a higher frequency compared to controls. Five CR polymorphisms were found to differ significantly in the two study populations compared to controls, and all, except one (T152C), are linked to those haplogroups. Conclusions/Significance: It can be concluded that haplogroup J is a risk factor for AMD, whereas haplogroup H seems t
Cross-Talk Between Interferon-Ξ³ and Hedgehog Signaling Regulates Adipogenesis
OBJECTIVE: T cells and level of the cytokine interferon-Ξ³ (IFN-Ξ³) are increased in adipose tissue in obesity. Hedgehog (Hh) signaling has been shown to potently inhibit white adipocyte differentiation. In light of recent findings in neurons that IFN-Ξ³ and Hh signaling cross-talk, we examined their potential interaction in the context of adipogenesis. RESEARCH DESIGN AND METHODS: We used Hh reporter cells, cell lines, and primary adipocyte differentiation models to explore costimulation of IFN-Ξ³ and Hh signaling. Genetic dissection using Ifngr1<sup>-/-</sup> and Stat1<sup>-/-</sup> mouse embryonic fibroblasts, and ultimately, anti-IFN-Ξ³ neutralization and expression profiling in obese mice and humans, respectively, were used to place the findings into the in vivo context. RESULTS: T-cell supernatants directly inhibited hedgehog signaling in reporter and 3T3-L1 cells. Intriguingly, using blocking antibodies, Ifngr1<sup>-/-</sup> and Stat1<sup>-/-</sup> cells, and simultaneous activation of Hh and IFN-Ξ³ signaling, we showed that IFN-Ξ³ directly suppresses Hh stimulation, thus rescuing adipogenesis. We confirmed our findings using primary mouse and primary human (pre)adipocytes. Importantly, robust opposing signals for Hh and T-cell pathways in obese human adipose expression profiles and IFN-Ξ³ depletion in mice identify the system as intact in adipose tissue in vivo. CONCLUSIONS: These results identify a novel antagonistic cross-talk between IFN-Ξ³ and Hh signaling in white adipose tissue and demonstrate IFN-Ξ³ as a potent inhibitor of Hh signaling
Excision of HIV-1 Proviral DNA by Recombinant Cell Permeable Tre-Recombinase
Over the previous years, comprehensive studies on antiretroviral drugs resulted in the successful introduction of highly active antiretroviral therapy (HAART) into clinical practice for treatment of HIV/AIDS. However, there is still need for new therapeutic approaches, since HAART cannot eradicate HIV-1 from the infected organism and, unfortunately, can be associated with long-term toxicity and the development of drug resistance. In contrast, novel gene therapy strategies may have the potential to reverse the infection by eradicating HIV-1. For example, expression of long terminal repeat (LTR)-specific recombinase (Tre-recombinase) has been shown to result in chromosomal excision of proviral DNA and, in consequence, in the eradication of HIV-1 from infected cell cultures. However, the delivery of Tre-recombinase currently depends on the genetic manipulation of target cells, a process that is complicating such therapeutic approaches and, thus, might be undesirable in a clinical setting. In this report we demonstrate that E.coli expressed Tre-recombinases, tagged either with the protein transduction domain (PTD) from the HIV-1 Tat trans-activator or the translocation motif (TLM) of the Hepatitis B virus PreS2 protein, were able to translocate efficiently into cells and showed significant recombination activity on HIV-1 LTR sequences. Tre activity was observed using episomal and stable integrated reporter constructs in transfected HeLa cells. Furthermore, the TLM-tagged enzyme was able to excise the full-length proviral DNA from chromosomal integration sites of HIV-1-infected HeLa and CEM-SS cells. The presented data confirm Tre-recombinase activity on integrated HIV-1 and provide the basis for the non-genetic transient application of engineered recombinases, which may be a valuable component of future HIV eradication strategies
Obesity, Type 2 Diabetes and Bone in Adults.
In an increasingly obese and ageing population, type 2 diabetes (T2DM) and osteoporotic fracture are major public health concerns. Understanding how obesity and type 2 diabetes modulate fracture risk is important to identify and treat people at risk of fracture. Additionally, the study of the mechanisms of action of obesity and T2DM on bone has already offered insights that may be applicable to osteoporosis in the general population. Most available evidence indicates lower risk of proximal femur and vertebral fracture in obese adults. However the risk of some fractures (proximal humerus, femur and ankle) is higher, and a significant number fractures occur in obese people. BMI is positively associated with BMD and the mechanisms of this association in vivo may include increased loading, adipokines such as leptin, and higher aromatase activity. However, some fat depots could have negative effects on bone; cytokines from visceral fat are pro-resorptive and high intramuscular fat content is associated with poorer muscle function, attenuating loading effects and increasing falls risk. T2DM is also associated with higher bone mineral density (BMD), but increased overall and hip fracture risk. There are some similarities between bone in obesity and T2DM, but T2DM seems to have additional harmful effects and emerging evidence suggests that glycation of collagen may be an important factor. Higher BMD but higher fracture risk presents challenges in fracture prediction in obesity and T2DM. Dual energy X-ray absorptiometry underestimates risk, standard clinical risk factors may not capture all relevant information, and risk is under-recognised by clinicians. However, the limited available evidence suggests that osteoporosis treatment does reduce fracture risk in obesity and T2DM with generally similar efficacy to other patients
Sox2 Is Essential for Formation of Trophectoderm in the Preimplantation Embryo
In preimplantation mammalian development the transcription factor Sox2 (SRY-related HMG-box gene 2) forms a complex with Oct4 and functions in maintenance of self-renewal of the pluripotent inner cell mass (ICM). Previously it was shown that Sox2-/- embryos die soon after implantation. However, maternal Sox2 transcripts may mask an earlier phenotype. We investigated whether Sox2 is involved in controlling cell fate decisions at an earlier stage.We addressed the question of an earlier role for Sox2 using RNAi, which removes both maternal and embryonic Sox2 mRNA present during the preimplantation period. By depleting both maternal and embryonic Sox2 mRNA at the 2-cell stage and monitoring embryo development in vitro we show that, in the absence of Sox2, embryos arrest at the morula stage and fail to form trophectoderm (TE) or cavitate. Following knock-down of Sox2 via three different short interfering RNA (siRNA) constructs in 2-cell stage mouse embryos, we have shown that the majority of embryos (76%) arrest at the morula stage or slightly earlier and only 18.7-21% form blastocysts compared to 76.2-83% in control groups. In Sox2 siRNA-treated embryos expression of pluripotency associated markers Oct4 and Nanog remained unaffected, whereas TE associated markers Tead4, Yap, Cdx2, Eomes, Fgfr2, as well as Fgf4, were downregulated in the absence of Sox2. Apoptosis was also increased in Sox2 knock-down embryos. Rescue experiments using cell-permeant Sox2 protein resulted in increased blastocyst formation from 18.7% to 62.6% and restoration of Sox2, Oct4, Cdx2 and Yap protein levels in the rescued Sox2-siRNA blastocysts.We conclude that the first essential function of Sox2 in the preimplantation mouse embryo is to facilitate establishment of the trophectoderm lineage. Our findings provide a novel insight into the first differentiation event within the preimplantation embryo, namely the segregation of the ICM and TE lineages
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