534 research outputs found
The effects of exotic weed Flaveria bidentis with different invasion stages on soil bacterial community structures
A new exotic weed, Flaveria bidentis, is spreading in central China where it forms dense monospecific patches modifying the structure of different native ecosystems and threatening native aboveground biodiversity. However, little is known about the consequences of such an invasion for soil bacterial community, especially its effect pattern at different invasion stages. In this study, soil samples were taken in native ecosystems that were uninvaded, partially invaded (transition), and severely invaded by F. bidentis. The bacterial richness and diversity in F. bidentis in rhizospheres soil was evaluated using denaturing gradient gel electrophoresis (DGGE) analysis. Different stages of F. bidentis invasion can trigger changes in soil physicochemical properties in particularly in available N and P F. bidentis invasion significantly decreased the richness of soil bacterial community, and the decline contents were positively correlated with invasion progress. In the invaded soils, bacterial species in Proteobacteria, Chloroflexi and Actinomycetes decreased with invasion, with the greatest reduction in relative abundance occurring for Proteobacteria, which was the dominant species in the native soils. Invasion of F. bidentis corresponded with an alteration in the structure of soil bacterial community, and soil microbial biomass as well, thus soil environment modification was expected to promote spreading of this exotic weeds in turn.Key words: Biological invasion, Flaveria bidentis, soil nutrients, soil bacteria, polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE)
Inflammatory signaling compromises cell responses to interferon alpha.
Interferon alpha (IFNα) is widely used for treatment of melanoma and certain other malignancies. This cytokine as well as the related IFNβ exerts potent anti-tumorigenic effects; however, their efficacy in patients is often suboptimal. Here, we report that inflammatory signaling impedes the effects of IFNα/β. Melanoma cells can secrete pro-inflammatory cytokines that inhibit cellular responses to IFNα/β via activating the ligand-independent pathway for the phosphorylation and subsequent ubiquitination and accelerated degradation of the IFNAR1 chain of type I IFN receptor. Catalytic activity of the p38 protein kinase was required for IFNAR1 downregulation and inhibition of IFNα/β signaling induced by proinflammatory cytokines such as interleukin 1 (IL-1). Activation of p38 kinase inversely correlated with protein levels of IFNAR1 in clinical melanoma specimens. Inhibition of p38 kinase augmented the inhibitory effects of IFNα/β on cell viability and growth in vitro and in vivo. The roles of inflammation and p38 protein kinase in regulating cellular responses to IFNα/β in normal and tumor cells are discussed
Generation of Stable Pluripotent Stem Cells From NOD Mouse Tail-Tip Fibroblasts
OBJECTIVE: The NOD mouse strain has been widely used to investigate the pathology and genetic susceptibility for type 1 diabetes. Induced pluripotent stem cells (iPSCs) derived from this unique mouse strain would enable new strategies for investigating type 1 diabetes pathogenesis and potential therapeutic targets. The objective of this study was to determine whether somatic fibroblasts from NOD mice could be reprogrammed to become iPSCs, providing an alternative source of stem cells for the production of genetically modified NOD cells and mice. RESEARCH DESIGN AND METHODS: Adult tail-tip fibroblasts from male NOD mice were reprogrammed by retroviral transduction of the coding sequences of three transcription factors, OCT4, SOX2, and KLF4, in combination with a histone deacetylase inhibitor, valproic acid. RESULTS: Eighteen NOD iPSC lines were generated, and three of these cell lines were further characterized. All three cell lines exhibited silencing of the three reprogramming transgenes and reactivation of endogenous pluripotent markers (OCT4, SOX2, NANOG, REX1, and SSEA1). These NOD iPSCs readily differentiated in vitro to form embryoid bodies and in vivo by teratoma formation in immunodeficient mice. Moreover, NOD iPSCs were successfully transfected with a reporter transgene and were capable of contributing to the inner cell mass of C57BL/6 blastocysts, leading to the generation of a chimeric mouse. CONCLUSIONS: Adult tail-tip fibroblasts from NOD mice can be reprogrammed, without constitutive ectopic expression of transcription factors, to produce iPSCs that exhibit classic mouse embryonic stem cell (ESC) features. These NOD iPSCs can be maintained and propagated under normal ESC culture conditions to produce genetically altered cell lines, differentiated cells, and chimeric mice
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Impact of price reductions, subsidies, or financial incentives on healthy food purchases and consumption: a systematic review and meta-analysis.
Poor diets are a global concern and are linked with various adverse health outcomes. Healthier foods such as fruit and vegetables are often more expensive than unhealthy options. This study aimed to assess the effect of price reductions for healthy food (including fruit and vegetables) on diet. We performed a systematic review and meta-analysis on studies that looked at the effects of financial incentives on healthy food. Main outcomes were change in purchase and consumption of foods following a targeted price reduction. We searched electronic databases (MEDLINE, EconLit, Embase, Cinahl, Cochrane Library, and Web of Science), citations, and used reference screening to identify relevant studies from Jan 1, 2013, to Dec 20, 2021, without language restrictions. We stratified results by population targeted (low-income populations vs general population), the food group that the reduction was applied to (fruit and vegetables, or other healthier foods), and study design. Percentage price reduction was standardised to assess the effect in meta-analyses. Study quality was assessed using the Cochrane Risk of Bias tool and Newcastle-Ottawa Scale. 34 studies were eligible; 15 took place in supermarkets and eight took place in workplace canteens in high-income countries, and 21 were targeted at socioeconomically disadvantaged communities. Pooled analyses of 14 studies showed a price reduction of 20% resulted in increases in fruit and vegetable purchases by 16·62% (95% CI 12·32 to 20·91). Few studies had maintained the price reduction for over 6 months. In conclusion, price reductions can lead to increases in purchases of fruit and vegetables, potentially sufficient to generate health benefits, if sustained
Coordinated Translocation of Mammalian Gli Proteins and Suppressor of Fused to the Primary Cilium
Intracellular transduction of Hedgehog (Hh) signals in mammals requires functional primary cilia. The Hh signaling effectors, the Gli family of transcription factors, and their negative regulator, Suppressor of Fused (Sufu), accumulate at the tips of cilia; however, the molecular mechanism regulating this localization remains elusive. In the current study, we show that the ciliary localization of mammalian Gli proteins depends on both their N-terminal domains and a central region lying C-terminal to the zinc-finger DNA-binding domains. Invertebrate Gli homologs Ci and Tra1, when over-expressed in ciliated mouse fibroblasts, fail to localize to the cilia, suggesting the lack of a vertebrate-specific structural feature required for ciliary localization. We further show that activation of protein kinase A (PKA) efficiently inhibits ciliary localization of Gli2 and Gli3, but only moderately affects the ciliary localization of Gli1. Interestingly, variants of Gli2 mimicking the phosphorylated or non-phosphorylated states of Gli2 are both localized to the cilia, and their ciliary localizations are subjected to the inhibitory effect of PKA activation, suggesting a likely indirect mechanism underlying the roles of PKA in Gli ciliary localization. Finally, we show that ciliary localization of Sufu is dependent on ciliary-localized Gli proteins, and is inhibited by PKA activation, suggesting a coordinated mechanism for the ciliary translocation of Sufu and Gli proteins
Oxygenated volatile organic compounds (VOCs) as significant but varied contributors to VOC emissions from vehicles
Vehicular emissions are an important source for volatile organic compounds (VOCs) in urban and downwind regions. In this study, we conducted a chassis dynamometer study to investigate VOC emissions from vehicles using gasoline, diesel, and liquefied petroleum gas (LPG) as fuel. Time-resolved VOC emissions from vehicles are chemically characterized by a
proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS) with
high frequency. Our results show that emission factors of VOCs generally
decrease with the improvement of emission standards for gasoline vehicles,
whereas variations in emission factors for diesel vehicles with emission
standards are more diverse. Mass spectrum analysis of the PTR-ToF-MS suggests that cold starts significantly influence VOC emissions of gasoline vehicles, while the influences are less important for diesel vehicles. Large differences in VOC emissions between gasoline and diesel vehicles are observed with emission factors of most VOC species from diesel vehicles being higher than gasoline vehicles, especially for most oxygenated volatile organic compounds (OVOCs) and heavier aromatics. These results indicate quantification of heavier species by the PTR-ToF-MS may be important in the characterization of vehicular exhausts. Our results suggest that VOC pairs (e.g., C14 aromatics / toluene ratio) could potentially provide good indicators for distinguishing emissions from gasoline and diesel vehicles. The fractions of OVOCs in total VOC emissions are determined by combining measurements of hydrocarbons from canisters and online observations of the PTR-ToF-MS. We show that OVOCs contribute 9.4 % ± 5.6 % of total VOC emissions for gasoline vehicles, while the fractions are significantly higher for diesel vehicles (52 %–71 %), highlighting the importance of detecting these OVOC species in diesel emissions. Our study demonstrated that the large number of OVOC species measured by the PTR-ToF-MS are important in the characterization of VOC emissions from vehicles.</p
Calcium phosphate-hybridized tendon graft to enhance tendon-bone healing two years after ACL reconstruction in goats
Abstract Background We developed a novel technique to improve tendon-bone attachment by hybridizing calcium phosphate (CaP) with a tendon graft using an alternate soaking process. However, the long-term result with regard to the interface between the tendon graft and the bone is unclear. Methods We analyzed bone tunnel enlargement by computed tomography and histological observation of the interface and the tendon graft with and without the CaP hybridization 2 years after anterior cruciate ligament (ACL) reconstruction in goats using EndoButton and the postscrew technique (CaP, n = 4; control, n = 4). Results The tibial bone tunnel enlargement rates in the CaP group were lower than those in the control group (p p p Conclusions The CaP-hybridized tendon graft enhanced the tendon-bone healing 2 years after ACL reconstruction in goats. The use of CaP-hybridized tendon grafts can reduce the bone tunnel enlargement and gap area associated with the direct insertion-like formation in the interface near the joint.</p
Wdpcp, a PCP Protein Required for Ciliogenesis, Regulates Directional Cell Migration and Cell Polarity by Direct Modulation of the Actin Cytoskeleton
Planar cell polarity (PCP) regulates cell alignment required for collective cell movement during embryonic development. This requires PCP/PCP effector proteins, some of which also play essential roles in ciliogenesis, highlighting the long-standing question of the role of the cilium in PCP. Wdpcp, a PCP effector, was recently shown to regulate both ciliogenesis and collective cell movement, but the underlying mechanism is unknown. Here we show Wdpcp can regulate PCP by direct modulation of the actin cytoskeleton. These studies were made possible by recovery of a Wdpcp mutant mouse model. Wdpcp-deficient mice exhibit phenotypes reminiscent of Bardet-Biedl/Meckel-Gruber ciliopathy syndromes, including cardiac outflow tract and cochlea defects associated with PCP perturbation. We observed Wdpcp is localized to the transition zone, and in Wdpcp-deficient cells, Sept2, Nphp1, and Mks1 were lost from the transition zone, indicating Wdpcp is required for recruitment of proteins essential for ciliogenesis. Wdpcp is also found in the cytoplasm, where it is localized in the actin cytoskeleton and in focal adhesions. Wdpcp interacts with Sept2 and is colocalized with Sept2 in actin filaments, but in Wdpcp-deficient cells, Sept2 was lost from the actin cytoskeleton, suggesting Wdpcp is required for Sept2 recruitment to actin filaments. Significantly, organization of the actin filaments and focal contacts were markedly changed in Wdpcp-deficient cells. This was associated with decreased membrane ruffling, failure to establish cell polarity, and loss of directional cell migration. These results suggest the PCP defects in Wdpcp mutants are not caused by loss of cilia, but by direct disruption of the actin cytoskeleton. Consistent with this, Wdpcp mutant cochlea has normal kinocilia and yet exhibits PCP defects. Together, these findings provide the first evidence, to our knowledge, that a PCP component required for ciliogenesis can directly modulate the actin cytoskeleton to regulate cell polarity and directional cell migration
Subduction polarity reversal facilitated by plate coupling during arc-continent collision: Evidence from the Western Kunlun orogenic belt, NW China
Primary Cilia Are Not Required for Normal Canonical Wnt Signaling in the Mouse Embryo
Sonic hedgehog (Shh) signaling in the mouse requires the microtubule-based organelle, the primary cilium. The primary cilium is assembled and maintained through the process of intraflagellar transport (IFT) and the response to Shh is blocked in mouse mutants that lack proteins required for IFT. Although the phenotypes of mouse IFT mutants do not overlap with phenotypes of known Wnt pathway mutants, recent studies report data suggesting that the primary cilium modulates responses to Wnt signals.We therefore carried out a systematic analysis of canonical Wnt signaling in mutant embryos and cells that lack primary cilia because of loss of the anterograde IFT kinesin-II motor (Kif3a) or IFT complex B proteins (Ift172 or Ift88). We also analyzed mutant embryos with abnormal primary cilia due to defects in retrograde IFT (Dync2h1). The mouse IFT mutants express the canonical Wnt target Axin2 and activate a transgenic canonical Wnt reporter, BAT-gal, in the normal spatial pattern and to the same quantitative level as wild type littermates. Similarly, mouse embryonic fibroblasts (MEFs) derived from IFT mutants respond normally to added Wnt3a. The switch from canonical to non-canonical Wnt also appears normal in IFT mutant MEFs, as both wild-type and mutant cells do not activate the canonical Wnt reporter in the presence of both Wnt3a and Wnt5a.We conclude that loss of primary cilia or defects in retrograde IFT do not affect the response of the midgestation embryo or embryo-derived fibroblasts to Wnt ligands
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