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Compact tomato seedlings and plants upon overexpression of a tomato chromatin remodelling ATPase gene

Control of plant growth is an important aspect of crop productivity and yield in agriculture. Overexpression of the At CHR12/ 23 genes in Arabidopsis thaliana reduced growth habit without other morphological changes. These two genes encode Snf2 chromatin remodelling ATPases. Here, we translate this approach to the horticultural crop tomato ( Solanum lycopersicum). We identified and cloned the single tomato ortholog of the two Arabidopsis Snf2 genes, designated Sl CHR1. Transgenic tomato plants (cv. Micro-Tom) that constitutively overexpress the coding sequence of Sl CHR1 show reduced growth in all developmental stages of tomato. This confirms that Sl CHR1 combines the functions of both Arabidopsis genes in tomato. Compared to the wild type, the transgenic seedlings of tomato have significantly shorter roots, hypocotyls and reduced cotyledon size. Transgenic plants have a much more compact growth habit with markedly reduced plant height, severely compacted reproductive structures with smaller flowers and smaller fruits. The results indicate that either GMO-based or non- GMO-based approaches to modulate the expression of chromatin remodelling ATPase genes could develop into methods to control plant growth, for example to replace the use of chemical growth retardants. This approach is likely to be applicable and attractive for any crop for which growth habit reduction has added value.

Consequences of the integration of a hyperbolic funnel into a showerhead for droplets, jet break-up lengths, and physical-chemical parameters

Introducing a hyperbolic vortex into a showerhead is a possibility to achieve higher spray velocities for a given discharge without reducing the nozzle diameter. Due to the introduction of air bubbles into the water by the vortex, the spray is pushed from a transition (dripping faucet) regime into a jetting regime, which results in higher droplet and jet velocities using the same nozzle diameter and throughput. The same droplet and jet diameters were realized compared to a showerhead without a vortex. Assuming that the satisfaction of a shower experience is largely dependent on the droplet size and velocity, the implementation of a vortex in the showerhead could provide the same shower experience with 14% less water consumption compared to the normal showerhead. A full optical and physical analysis was presented, and the important chemical parameters were investigated.

OPTIMAX 2017 Radiation dose, image quality optimisation, the use of new technology in medical imaging

Evidence for sex‑specific intramuscular changes associated to physical weakness in adults older than 75 years

Lichamelijke zwakte is een belangrijk onderdeel van kwetsbaarheid en komt veel voor bij oudere volwassenen. Terwijl vrouwen een hogere prevalentie en een eerder begin van kwetsbaarheid kennen zijn sekseverschillen in de ontwikkeling van lichamelijke zwakte nauwelijks bestudeerd. Daarom hebben we in spieren de veranderingen onderzocht die onderscheid maken tussen fitte en zwakke ouderen voor elk geslacht afzonderlijk. Mannen (n = 28) en vrouwen (n = 26) van 75 jaar en ouder werden gegroepeerd op basis van hun fysieke prestatiecriteria. Er werd gebruik gemaakt van spierbiopten genomen uit de vastus lateralis-spier voor genexpressie- en histologisch onderzoek. Er werden paarsgewijze vergelijkingen gemaakt tussen de sterkste en de zwakste groepen voor elk geslacht afzonderlijk, en potentiële geslachts-specifieke effecten werden beoordeeld. Zwakke vrouwen toonden een hogere expressie van ontstekingsroutes, infiltratie van NOX2-immuuncellen, samen met een hogere VCAM1-expressie. Zwakke mannen werden gekenmerkt door een kleinere diameter van type 2 (snelle) spiervezels en lagere expressie van PRKN. Zwakte-geassocieerde genexpressie-veranderingen in de spieren waren verschillend van veroudering-geassocieerde genexpressie-veranderingen, wat erop wijst dat de pathofysiologie van fysieke zwakte niet noodzakelijkerwijs afhankelijk is van veroudering. We concluderen dat zwakte-geassocieerde veranderingen in de spieren sekse-specifiek zijn. Aanbevolen wordt om bij onderzoek naar kwetsbaarheid rekening te houden met sekseverschillen, omdat deze verschillen een grote impact kunnen hebben over de ontwikkeling van (farmaceutische) interventies tegen kwetsbaarheid.

Over-expression of Arabidopsis AtCHR23 chromatin remodeling ATPase results in increased variability of growth and gene expression

Plants are sessile organisms that deal with their -sometimes adverse- environment in well-regulated ways. Chromatin remodeling involving SWI/SNF2-type ATPases is thought to be an important epigenetic mechanism for the regulation of gene expression in different developmental programs and for integrating these programs with the response to environmental signals. In this study, we report on the role of chromatin remodeling in Arabidopsis with respect to the variability of growth and gene expression in relationship to environmental conditions.

High peak settlement of Diadema antillarum on different artificial collectors in the Eastern Caribbean

The massive die-off of the herbivorous sea urchin Diadema antillarum in 1983 and 1984 resulted in phase shifts on Caribbean coral reefs, where macroalgae replaced coral as the most dominant benthic group. Since then, D. antillarum recovery has been slow to non-existent on most reefs. Studying settlement rates can provide insight into the mechanisms constraining the recovery of D. antillarum, while efficient settlement collectors can be used to identify locations with high settlement rates and to collect settlers for restoration practices. The aim of this study was to compare pre and post die-off settlement rates and to determine possible settlement peaks in the Eastern Caribbean island of St. Eustatius. Additionally, we aimed to determine the effectiveness and reproducibility of five different settlement collectors for D. antillarum. D. antillarum settlement around St. Eustatius was highest in May, June and August and low during the rest of the study. Before the die-off, settlement recorded for Curaçao was high throughout the year and was characterized by multiple settlement peaks. Even though peak settlement rates in this study were in the same order of magnitude as in Curaçao before the die-off, overall yearly settlement rates around St. Eustatius were still lower. As no juvenile or adult D. antillarum were observed on the reefs around the settlement collectors, it is likely that other factors are hindering the recovery of the island's D. antillarum populations. Of all five materials tested, bio ball collectors were the most effective and reproducible method to monitor D. antillarum settlement. Panels yielded the least numbers of settlers, which can partly be explained by their position close to the seabed. Settler collection was higher in mid-water layers compared to close to the bottom and maximized when strings of bio balls were used instead of clumps. We recommend research into the feasibility of aiding D. antillarum recovery by providing suitable settlement substrate during the peak of the settlement season and adequate shelter to increase post-settlement survival of settlers. The bio ball collectors could serve as a suitable settlement substrate for this new approach of assisted natural recovery.