Interactions between Leptosphaeria maculans, causal agent of stem canker of oilseed rape, and its Brassica hosts are models of choice to explore the multiplicity of ‘gene-for-gene’ complementarities ...and how they diversified to increased complexity in the course of plant–pathogen co-evolution. Here, we support this postulate by investigating the AvrLm10 avirulence that induces a resistance response when recognized by the Brassica nigra resistance gene Rlm10.
Using genome-assisted map-based cloning, we identified and cloned two AvrLm10 candidates as two genes in opposite transcriptional orientation located in a subtelomeric repeat-rich region of the genome. The AvrLm10 genes encode small secreted proteins and show expression profiles in planta similar to those of all L. maculans avirulence genes identified so far.
Complementation and silencing assays indicated that both genes are necessary to trigger Rlm10 resistance. Three assays for protein–protein interactions showed that the two AvrLm10 proteins interact physically in vitro and in planta.
Some avirulence genes are recognized by two distinct resistance genes and some avirulence genes hide the recognition specificities of another. Our L. maculans model illustrates an additional case where two genes located in opposite transcriptional orientation are necessary to induce resistance. Interestingly, orthologues exist for both L. maculans genes in other phytopathogenic species, with a similar genome organization, which may point to an important conserved effector function linked to heterodimerization of the two proteins.
Nowadays, researchers focus more on developing smart materials that respond to different stimuli for harvesting energy output. In this paper, the pyroelectric energy harvesting capabilities of smart ...terpolymer poly(vinylidene-fluoride-trifluoroethylene-chlorotrifluoroethylene) PVDF-TrFE-CTFE-based nanocomposites have been investigated. Sodium niobate (NaNbO3) from the perovskite family is selected as the filler. The Sol-gel method is used to synthesise NaNbO3 nanoparticles, and solvent-cast films for different weight fractions (0–20%) of fillers have been fabricated. Structural, morphological, and dielectric properties of the polymer nanocomposite samples were done at room temperature. The ferroelectric properties of the terpolymer is improved with filler addition. The thermal stability of composite films was confirmed using differential scanning calorimetric (DSC) studies. The thermodynamic Olsen cycle was applied to nanocomposites for calculating the harvested energy output. Maximum energy density is obtained for higher filler loading (20 wt % sodium niobate). The operating temperatures were selected at 303 K and 333 K with an applied field of 130 kV/cm. The results show that including NaNbO3 in the relaxor terpolymer matrix considerably enhances the energy harvesting density of the nanocomposites, indicating that they are promising materials for designing thermally stable energy harvesting systems.
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•Terpolymer nanocomposite films are fabricated using solvent casting method.•Electro active phase for energy conversion get enhanced with filler addition.•A low grade heat harvesting system is made using Olsen cycle based thermal energy conversion.•Composite films produced a maximum energy density of 68 J/L percycle at the selected electric fields.
Copper isotopes (δ65Cu) in hydrothermal fluids have the potential to provide information on ore‐forming processes occurring below the seafloor, but Cu isotope data from high‐temperature fluids are ...scarce. Here, we examine the extent to which coexisting sulfide minerals in a hydrothermal chimney can preserve fluid Cu isotope ratios using a fluid‐solid pair of a black smoker (333°C) from the Roman Ruins vent area (PACMANUS) in the Manus Basin. Two ca. 3 cm long transects through the chalcopyrite‐rich chimney wall show an increase in δ65Cu from 0.48 to 2.28‰ from the interior to the exterior, coupled with limited variation in sulfide δ34S (1.52–4.72‰). The Cu isotopic composition of chalcopyrite from the innermost wall closely resembles the δ65Cu value of the paired hydrothermal fluid, indicating that chalcopyrite in the inner ∼5 mm of the chimney records the Cu isotope ratio of the venting fluid. Beyond this, an increase in sulfide δ65Cu toward the exterior correlates with an increase in the relative abundance of secondary Cu sulfides. The appearance of bornite coincides with the presence of small barite crystals, suggesting this represents a redox gradient between reduced hydrothermal fluids and oxidized seawater admixing inwards. Elevated δ65Cu in this zone can be explained by the precipitation of secondary Cu sulfides from 65Cu‐enriched fluids formed during oxidative chalcopyrite dissolution. Our findings indicate that interactions with oxidizing seawater shift chalcopyrite δ65Cu values over small spatial scales, and that caution must be applied if chimney sulfides are used to reconstruct δ65Cu values of high‐temperature hydrothermal fluids.
Plain Language Summary
Kilometers below the surface of the ocean, hydrothermal “chimney” structures emit hot and metal‐rich fluids from the seafloor. The chemical composition of these hot fluids can tell about the reactions that occur beneath the seafloor. In this study, we test how copper‐bearing minerals in a hydrothermal chimney record and preserve the copper isotopic composition of these hot fluids. To do so, we compare copper isotope ratios in a hydrothermal fluid and its paired chimney from a seafloor hot spring near Papua New Guinea and find that these ratios are very similar for minerals only in the innermost part of the chimney. Copper isotope ratios increase as the mineralogy of copper changes toward the outside of the chimney wall. This appears to result from cold seawater that enters the chimney and modifies the chemistry and mineralogy of the minerals in the structure. The resulting changes in copper isotope ratios within small cm‐scales of the chimney wall are as large as overall ranges observed in copper isotope ratios from seafloor hot springs globally. Therefore, our findings act as a cautionary tale for the use of chimney minerals to reconstruct the copper isotopic composition of hydrothermal fluids.
Key Points
Hydrothermal fluid Cu isotope ratios are preserved in chalcopyrite in the innermost part of a black smoker chimney
Cu isotope ratios are altered by seawater‐driven oxidative dissolution of chalcopyrite and precipitation of bornite and chalcocite
Bulk chimney Cu isotope ratios cannot be used as a record of fluid Cu isotope values
Abstract
Objectives
This study examined whether oral health is a neglected aspect of subjective well-being (SWB) among older adults. The key research question was whether deterioration in oral health ...among dentate older adults living in England was associated with decreases in SWB, using measures of eudemonic, evaluative, and affective dimensions of well-being.
Methods
This secondary analysis used data from the third (2006–2007) and fifth (2010–2011) waves of respondents aged 50 and older from the English Longitudinal Study of Ageing (ELSA). We fitted multivariable regression models to examine the effects of changes in oral impacts on daily life and edentulism (complete tooth loss) on SWB (quality of life, life satisfaction, and depressive symptomatology).
Results
A worsening in both oral health measures was associated with an increase in depressive symptoms even after adjusting for time-varying confounders including declining health, activities of daily living, and reduced social support. Becoming edentate was also associated with decreases in quality of life and life satisfaction.
Discussion
A deterioration in oral health and oral health–related quality of life increases the risk of depressive symptoms among older adults and highlights the importance of oral health as a determinant of subjective well-being in later life.
ObjectivePremature ovarian failure (POF) encompasses a heterogeneous spectrum of conditions, with phenotypic variability among patients. The etiology of POF remains unknown in most cases. We ...performed a global phenotyping of POF women with the aim of better orienting attempts at an etiological diagnosis.Design and methodsWe performed a mixed retrospective and prospective study of clinical, biological, histological, morphological, and genetic data relating to 357 consecutive POF patients between 1997 and 2008. The study was conducted at a reproductive endocrinology referral center.ResultsSeventy-six percent of the patients presented with normal puberty and secondary amenorrhea. Family history was present in 14% of the patients, clinical and/or biological autoimmunity in 14.3%. Fifty-six women had a fluctuating form of POF. The presence of follicles was suggested at ultrasonography in 50% of the patients, and observed in 29% at histology; the negative predictive value of the presence of follicles at ultrasonography was 77%. Bone mineral density alterations were found in 58% of the women. Eight patients had X chromosomal abnormalities other than Turner's syndrome, eight other patients evidenced FMR1 pre-mutation. Two other patients had autoimmune polyendocrine syndrome type 2 and 1.ConclusionA genetic cause of POF was identified in 25 patients, i.e. 7% of the whole cohort. POF etiology remains most often undiscovered. Novel strategies of POF phenotyping are in such content mandatory to improve the rate of POF patients for whom etiology is identified.
Modern-day requirements for efficient, eco-friendly, and self-powered devices have resulted in a growing interest in piezoelectric polymers among the scientific community. Polyvinylidene fluoride ...(PVDF) is an excellent electroactive polymer that is flexible, with high mechanical strength, thermal stability, and biocompatibility. The relatively low cost and easiness to be fabricated into thin pliable films made PVDF one of the most studied polymers for the development of nanogenerators and wearable sensors. The piezoelectric properties and therefore the energy harvesting and sensing capabilities of PVDF are distinct characteristics of its electroactive polar phases, especially the β phase. Hence, several PVDF-based nanocomposites that could achieve a high β phase fraction have been widely explored. Electrospinning is one of the best methods for manufacturing such PVDF-based nanocomposite films. This article, therefore, highlights essential information about different electrospinning parameters which help to enhance the β phase in PVDF. The review then progresses into the recent developments and technological advances of electrospun PVDF-based nanocomposite devices in energy harvesting and sensing applications. The piezo-, pyro-, and triboelectric properties of PVDF allow the fabrication of conventional and hybrid nanogenerators. The later can harvest energy simultaneously from multiple sources, sense various fluctuations in their surroundings, and transmit the acquired data immediately when integrated with Bluetooth or wireless devices. They are fine models of self-powered, portable, multifunctional, and sustainable engineering. Finally, a peek into the other possible applications of electrospun PVDF-nanocomposite fibers is also made. Overall, the review aims to illustrate the innovative research and developments of PVDF fiber-based devices and the relevance and prospects they hold as future green sources of energy.
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Leptosphaeria maculans
‘brassicae’ (Lmb) and
Leptosphaeria maculans
‘lepidii’ (Lml) are closely related phytopathogenic species that exhibit a large macrosynteny but contrasting genome structure. Lmb ...has more than 30% of repeats clustered in large repeat-rich regions, while the Lml genome has only a small amount of evenly distributed repeats. Repeat-rich regions of Lmb are enriched in effector genes, expressed during plant infection. The distinct genome structures of Lmb and Lml provide an excellent model for comparing the organization of pathogenicity genes in relation to the chromatin landscape in two closely related phytopathogenic fungi. Here, we performed chromatin immunoprecipitation (ChIP) during axenic culture, targeting histone modifications typical for heterochromatin or euchromatin, combined with transcriptomic analysis to analyze the influence of chromatin organization on gene expression. In both species, we found that facultative heterochromatin is enriched with genes lacking functional annotation, including numerous effector and species-specific genes. Notably, orthologous genes located in H3K27me3 domains are enriched with effector genes. Compared to other fungal species, including Lml, Lmb is distinct in having large H3K9me3 domains associated with repeat-rich regions that contain numerous species-specific effector genes. Discovery of these two distinctive heterochromatin landscapes now raises questions about their involvement in the regulation of pathogenicity, the dynamics of these domains during plant infection and the selective advantage to the fungus to host effector genes in H3K9me3 or H3K27me3 domains.
Modern agriculture favours the selection and spread of novel plant diseases. Furthermore, crop genetic resistance against pathogens is often rendered ineffective within a few years of its commercial ...deployment. Leptosphaeria maculans, the cause of phoma stem canker of oilseed rape, develops gene-for-gene interactions with its host plant, and has a high evolutionary potential to render ineffective novel sources of resistance in crops. Here, we established a four-year field experiment to monitor the evolution of populations confronted with the newly released Rlm7 resistance and to investigate the nature of the mutations responsible for virulence against Rlm7. A total of 2551 fungal isolates were collected from experimental crops of a Rlm7 cultivar or a cultivar without Rlm7. All isolates were phenotyped for virulence and a subset was genotyped with neutral genetic markers. Virulent isolates were investigated for molecular events at the AvrLm4-7 locus. Whilst virulent isolates were not found in neighbouring crops, their frequency had reached 36% in the experimental field after four years. An extreme diversity of independent molecular events leading to virulence was identified in populations, with large-scale Repeat Induced Point mutations or complete deletion of AvrLm4-7 being the most frequent. Our data suggest that increased mutability of fungal genes involved in the interactions with plants is directly related to their genomic environment and reproductive system. Thus, rapid allelic diversification of avirulence genes can be generated in L. maculans populations in a single field provided that large population sizes and sexual reproduction are favoured by agricultural practices.
Rubber-rubber blends RRB's of natural rubber NR and butadiene rubber BR filled with carbon black CB were compounded on a two-roll mixing mill. Partition of CB in RRB's is a challenging problem in the ...rubber industry. Therefore, the present study aims to quantify CB's partitioning in NR/BR RRB's at different blending ratios using relative damping height measurements from the dynamic mechanical analysis DMA. To support the findings from the DMA, structural and morphological analyses were carried out using solid state nuclear magnetic resonance Solid State NMR and transmission electron microscope TEM respectively. Constrained regions in neat (unfilled) NR/BR RRB's were analysed for the first time by dynamic mechanical analysis and this was ascribed to the entanglements between NR and BR chains at the interface. The tanδmax analysis confirmed the presence of 80% of CB partitioned towards BR phase in 70/30 NR/BR blends. For 50/50 NR/BR blends, 6.4% of CB is partitioned towards BR phase and 38% of CB was partitioned towards BR phase in 30/70 NR/BR blends. This indicated preferential migration of CB to one of the phases based on rubber blend composition. Solid State NMR studies were in agreement with DMA analysis. TEM images of CB filled rubber blends represent a near to homogenous state of dispersion, where in the identification of individual rubber phases becomes more difficult at the nanometre scale. The CB networking and its migration to the dispersed phase was evident from the TEM analysis.
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•Partition of CB in NR/BR RRB's are determined using DMA and Solid-state NMR.•CB favoured the dispersed phase in NR/BR RRB's, i.e. BR in filled NR70, NR in filled NR50 and NR in filled NR30.•Tanδ curve of DMA confirmed 80%, 6.4% and 39% towards BR phase in filled NR70, filled NR50 and filled NR30.•Constrained regions calculated for NR and BR using DMA and are in excellent agreement to %CB partitioned in NR/BR RRB's.•Partitioning of CB calculated from DMA are in good agreement with peak intensity and peak width on Solid-state NMR spectra.
The actual displacement field in a glass during an in-situ Vickers indentation experiment was determined by means of X-ray tomography, thanks to the addition of 4 vol % of X-ray absorbing particles, ...which acted as a speckle to further proceed through digital volume correlation. This displacement was found to agree well with the occurrence of densification beneath the contact area. The intensity of the densification contribution (Blister field proposed by Yoffe) was characterized and provides evidence for the significant contribution of densification to the mechanical fields. Densification accounts for 27% of the volume of the imprint for the studied glass, that is expected to be less sensitive to densification than amorphous silica or window glass. A major consequence is that indentation cracking methods for the evaluation of the fracture toughness, when they are based on volume conservation, as in the case of Hill-Eshelby plastic inclusion theory, are not suitable to glass. The onset for the formation of the subsurface lateral crack was also detected. The corresponding stress is ≈ 14 GPa and is in agreement with the intrinsic glass strength.
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