Plant Genome Size Influences Stress Tolerance of Invasive and Native Plants via Plasticity

Plant genome size influences the functional relationships between cellular and whole‐plant physiology, but we know little about its importance to plant tolerance of environmental stressors and how it contributes to range limits and invasion success. We used native and invasive lineages of a wetland plant to provide the first experimental test of the Large Genome Constraint Hypothesis (LGCH)—that plants with large genomes are less tolerant of environmental stress and less plastic under stress gradients than plants with small genomes. We predicted that populations with larger genomes would have a lower tolerance and less plasticity to a stress gradient than populations with smaller genomes. In replicated experiments in northern and southern climates in the United States, we subjected plants from 35 populations varying in genome size and lineage to two salinity treatments. We measured traits associated with growth, physiology, nutrition, defense, and plasticity. Using AICc model selection, we found all plant traits, except stomatal conductance, were influenced by environmental stressors and genome size. Increasing salinity was stressful to plants and affected most plant traits. Notably, biomass in the high‐salinity treatment was 3.0 and 4.9 times lower for the invasive and native lineages, respectively. Plants in the warmer southern greenhouse had higher biomass, stomate density, stomatal conductance, leaf toughness, and lower aboveground percentage of N and total phenolics than in the northern greenhouse. Moreover, responses to the salinity gradient were generally much stronger in the southern than northern greenhouse. Aboveground biomass increased significantly with genome size for the invasive lineage (43% across genome sizes) but not for the native. For 8 of 20 lineage trait comparisons, greenhouse location × genome size interaction was also significant. Interestingly, the slope of the relationship between genome size and trait means was in the opposite direction for some traits between the gardens providing mixed support for LGCH. Finally, for 30% of the comparisons, plasticity was significantly related to genome size—for some plant traits, the relationship was positive, and in others, it was negative. Overall, we found mixed support for LGCH and for the first time found that genome size is associated with plasticity, a trait widely regarded as important to invasion success

Dental Caries Prevention Strategies, Application of Evidence-Based Medicine. Part I. Basic Documents, Global and European Initiatives

Background and aim: Summarizing series of overview articles intends to show current strategy to prevent tooth decay and contemporary transnational initiatives aimed mainly at controlling caries in children and youth. In the first part of this series is defined the problem of dental caries in its social and public health context, taking account of new diagnostic technologies and decision-making processes about his healing or restoration. It is emphasized here the application of the concept of evidence based medicine evaluating the results published in information resources in terms of their scientific quality and weight recommendations for clinical practice and their projections into the current dental literature. The aim of this review is to characterize the basic current trends in dental caries prevention and their implementation of into individual and community preventive practice

HIV protease inhibition seen by X-ray diffraction and molecular dynamics

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Structure of the human NK cell NKR-P1:LLT1 receptor:ligand complex reveals clustering in the immune synapse.

Signaling by the human C-type lectin-like receptor, natural killer (NK) cell inhibitory receptor NKR-P1, has a critical role in many immune-related diseases and cancer. C-type lectin-like receptors have weak affinities to their ligands; therefore, setting up a comprehensive model of NKR-P1-LLT1 interactions that considers the natural state of the receptor on the cell surface is necessary to understand its functions. Here we report the crystal structures of the NKR-P1 and NKR-P1:LLT1 complexes, which provides evidence that NKR-P1 forms homodimers in an unexpected arrangement to enable LLT1 binding in two modes, bridging two LLT1 molecules. These interaction clusters are suggestive of an inhibitory immune synapse. By observing the formation of these clusters in solution using SEC-SAXS analysis, by dSTORM super-resolution microscopy on the cell surface, and by following their role in receptor signaling with freshly isolated NK cells, we show that only the ligation of both LLT1 binding interfaces leads to effective NKR-P1 inhibitory signaling. In summary, our findings collectively support a model of NKR-P1:LLT1 clustering, which allows the interacting proteins to overcome weak ligand-receptor affinity and to trigger signal transduction upon cellular contact in the immune synapse

A brief guide to polymer characterization: structure (IUPAC technical report)

To bolster the series of Brief Guides released by International Union of Pure and Applied Chemistry (IUPAC), here we introduce the first Brief Guide to Polymer Characterization. This article provides a concise overview of characterization methods for teachers, students, non-specialists, and newcomers to polymer science as well as being a useful manual for researchers and technicians. Unlike pure low molar mass chemical substances, polymers are not composed of identical molecules. The macromolecules which comprise a single polymer sample vary from one another, primarily in terms of size and shape, but often also in the arrangement or positioning of atoms within macromolecules (e.g., chain branching, isomerism, etc.). Polymer properties are often drastically different from those of other substances and their characterization relies on specialist equipment and/or common equipment used in a specialized way (e.g., particular sample preparation or data analysis). This Brief Guide focuses uniquely on the structural characterization (i.e., analyzing the molecular and multi-molecular aspects) of polymers. The complex nature of the structural variables possible in macromolecular materials often presents a challenge with regard to the detailed structural characterization of polymers. This Brief Guide provides a useful starting point to direct the reader to the most commonly used and useful techniques to characterize these structural variables

Opportunities and hurdles of edible insects for food and feed

Entomophagy, the consumption of insects, is promoted as an alternative sustainable source of protein for humans and animals. Seminal literature highlights predominantly the benefits, but with limited empirical support and evaluation. We highlight the historical significance of entomophagy by humans and key opportunities and hurdles identified by research to date, paying particular attention to research gaps. It is known that insects present a nutritional opportunity, being generally high in protein and key micronutrients, but it is unclear how their nutritional quality is influenced by what they are fed. Research indicates that, in ideal conditions, insects have a smaller environmental impact than more traditional Western forms of animal protein; less known is how to scale up insect production while maintaining these environmental benefits. Studies overall show that insects could make valuable economic and nutritional contributions to the food or feed systems, but there are no clear regulations in place to bring insects into such supply systems. Future research needs to examine how the nutritional value of insects can be managed systematically, establish clear processing and storage methodology, define rearing practices and implement regulations with regard to food and feed safety. Each of these aspects should be considered within the specifics of concrete supply and value chains, depending on whether insects are intended for food or for feed, to ensure insects are a sound economic, nutritional and sustainable protein alternative – not just a more expensive version of poultry for food, or soya for feed

Histone Deacetylase Activity Modulates Alternative Splicing

There is increasing evidence to suggest that splicing decisions are largely made when the nascent RNA is still associated with chromatin. Here we demonstrate that activity of histone deacetylases (HDACs) influences splice site selection. Using splicing-sensitive microarrays, we identified ∼700 genes whose splicing was altered after HDAC inhibition. We provided evidence that HDAC inhibition induced histone H4 acetylation and increased RNA Polymerase II (Pol II) processivity along an alternatively spliced element. In addition, HDAC inhibition reduced co-transcriptional association of the splicing regulator SRp40 with the target fibronectin exon. We further showed that the depletion of HDAC1 had similar effect on fibronectin alternative splicing as global HDAC inhibition. Importantly, this effect was reversed upon expression of mouse HDAC1 but not a catalytically inactive mutant. These results provide a molecular insight into a complex modulation of splicing by HDACs and chromatin modifications

Functional Foods and Functional Food Components in Prevention of Dental Karies

Introduction: The review article describes historical context of functional foods and functional food components, which, in addition to their nutritional value, show a positive effect on human health. Objectives: Research and practical usage of functional foods play role in the prevention and treatment of different diseases. Some of them may be beneficial in the prevention of dental decay. Anticariogenic potential of these substances has been tested in vitro, in experiments on animal models and in humans in situ and in vivo. In vitro studies monitor the effects of food components on growth, production of acids and adherence of microorganisms to hard dental structures in isolated microbial strains and in experimental biofilm model. As caries in situ model samples of hard dental tissues are being used, mounted into acrylic appliances and placed in the oral cavity of volunteers. Alternatively, there are clinical studies focusing on caries increment after the inclusion of investigational food components or placebo into diet. Of the substances present in plants and fruits, attention is drawn to polyphenols, flavonoids and procyanidins, which inhibit metabolism of microorganisms and glycosyltranspherase of cariogenic organisms, thus deteriorating their adherence to the tooth surface. A similar mechanism is ascribed to phosphate esters of carbohydrates, present in bee honey, propolis and also in non-refined sugar syrups of sugar beet and sugar cane. Replacement sweeteners, such as sugar polyalcohols and especially xylitol have been found to reduce cariogenic potential in many laboratory studies and clinical trials. Attention is also paid to the beneficial effect of food preservatives, benzoate, sorbate, sulphite and nitrite, which reduce the viability of cariogenic bacteria. Milk and milk products are sources of bioactive peptides and among them calcium salts of casein, casein glycomacropeptide and phosphopeptids seem to be very perspective. Probiotic microorganisms Lactobactillus reuteri, L. LG and other lactobacilli and bifidobacteria show favourable effect in the regulation of microbial community in the oral cavity. Conclusion: The research on functional foods and functional food components in relation to the oral health is very intensive. Many of the investigational substances may eventually be implemented in comprehensive strategies for the prevention of tooth decay as adjuncts to an effective oral hygiene and safe nutrition

Fluoride Content in Instant Milk Formulas available in the Czech Republic

The aim of the study was to estimate the contribution of instant milk formulas (IMFs) manufactured by Nutricia, Nestlé and Hero available at local food market to the fluoride intake of infants in the Czech Republic. Fluoride content in IMFs dissolved in recommended bottled waters for infants has been determined in order to estimate the background fluoride intake when recommending fluoride supplementation. Totally 8 IMFs brands for children aged 1-3 months, 8 for 4-10 months and 6 for >10-months were involved. Formulae were dissolved either in deionised water or in three brands of bottled waters for infants containing 0.06, 0.15 and 0.56 ppm of fluoride. Fluoride content in dissolved IMFs was determined after HMDS-facilitated diffusion, using a fluoride ion specific electrode ELIT 8221 (Nico, USA) and an ionometer InoLab pH/ION 735P (WTW, Germany). During preparation stage of this study it was found that the employed microdiffusion sample processing [25] gave more than 97 % fluoride recovery among samples. Results: Fluoride concentrations ranged in IMFs: < 0.02 to 0.66 ppm when dissolved in deionised water, 0.04-0.34, 0.08 to 0.48 and 0.38 to 1.05 ppm when dissolved in infant bottled waters with 0.06, 0.15 and 0.56 ppm F, respectively. One brand of IMF, Sunar Complex Premium (Hero), was supplemented by fluoride (0.50 mg F/100 g of pulver). Its fluoride content after dissolution in deionised water and bottled waters with 0.06, 0.15 and 0.56 ppm F amounted to 0.87, 0.86, 1.04 nd 1.28 ppm, respectively. It is thus recommended to use low fluoride water for the reconstitution of that fluoride-supplemented brand of IMF