Water Deficit History Selects Plant Beneficial Soil Bacteria Differently Under Conventional and Organic Farming

Water deficit tolerance is critical for plant fitness and survival, especially when successive drought events happen. Specific soil microorganisms are however able to improve plant tolerance to stresses, such as those displaying a 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity. Microorganisms adapted to dry conditions can be selected by plants over time because of properties such as sporulation, substrate preference, or cell-wall thickness. However, the complexity and interconnection between abiotic factors, like drought or soil management, and biotic factors, like plant species identity, make it difficult to elucidate the general selection processes of such microorganisms. Using a pot experiment in which wheat and barley were grown on conventional and organic farming soils, we determined the effect of water deficit history on soil microorganisms by comparing single and successive events of water limitation. The analysis showed that water deficit strongly impacts the composition of both the total microbial community (16S rRNA genes) and one of ACC deaminase-positive (acdS+) microorganisms in the rhizosphere. In contrast, successive dry conditions moderately influence the abundance and diversity of both communities compared to a single dry event. We revealed interactive effects of the farming soil type and the water deficit conditioning treatment. Indeed, possibly due to better nutrient status, plants grown on soils from conventional farming showed higher growth and were able to select more adapted microbial taxa. Some of them are already known for their plant-beneficial properties like the Actinobacteria Streptomyces, but interestingly, some Proteobacteria were also enriched after a water deficit history under conventional farming. Our approach allowed us to identify key microbial taxa promoting drought adaptation of cereals, thus improving our understanding of drought effects on plant-microbe interactions.

SmartSpectrometer-Embedded Optical Spectroscopy for Applications in Agriculture and Industry

The ongoing digitization of industry and agriculture can benefit significantly from optical spectroscopy. In many cases, optical spectroscopy enables the estimation of properties such as substance concentrations and compositions. Spectral data can be acquired and evaluated in real time, and the results can be integrated directly into process and automation units, saving resources and costs. Multivariate data analysis is needed to integrate optical spectrometers as sensors. Therefore, a spectrometer with integrated artificial intelligence (AI) called SmartSpectrometer and its interface is presented. The advantages of the SmartSpectrometer are exemplified by its integration into a harvesting vehicle, where quality is determined by predicting sugar and acid in grapes in the field.

Soil Texture, Sampling Depth and Root Hairs Shape the Structure of ACC Deaminase Bacterial Community Composition in Maize Rhizosphere

Preservation of the phytostimulatory functions of plant growth-promoting bacteria relies on the adaptation of their community to the rhizosphere environment. Here, an amplicon sequencing approach was implemented to specifically target microorganisms with 1-aminocyclopropane-1-carboxylate deaminase activity, carrying the acdS gene. We stated the hypothesis that the relative phylogenetic distribution of acdS carrying microorganisms is affected by the presence or absence of root hairs, soil type, and depth. To this end, a standardized soil column experiment was conducted with maize wild type and root hair defective rth3 mutant in the substrates loam and sand, and harvest was implemented from three depths. Most acdS sequences (99%) were affiliated to Actinobacteria and Proteobacteria, and the strongest influence on the relative abundances of sequences were exerted by the substrate. Variovorax, Acidovorax, and Ralstonia sequences dominated in loam, whereas Streptomyces and Agromyces were more abundant in sand. Soil depth caused strong variations in acdS sequence distribution, with differential levels in the relative abundances of acdS sequences affiliated to Tetrasphaera, Amycolatopsis, and Streptomyces in loam, but Burkholderia, Paraburkholderia, and Variovorax in sand. Maize genotype influenced the distribution of acdS sequences mainly in loam and only in the uppermost depth. Variovorax acdS sequences were more abundant in WT, but Streptomyces, Microbacterium, and Modestobacter in rth3 rhizosphere. Substrate and soil depth were strong and plant genotype a further significant single and interacting drivers of acdS carrying microbial community composition in the rhizosphere of maize. This suggests that maize rhizosphere acdS carrying bacterial community establishes according to the environmental constraints, and that root hairs possess a minor but significant impact on acdS carrying bacterial populations.

Oxytocin improves synchronisation in leader-follower interaction

The neuropeptide oxytocin has been shown to affect social interaction. Meanwhile, the underlying mechanism remains highly debated. Using an interpersonal finger-tapping paradigm, we investigated whether oxytocin affects the ability to synchronise with and adapt to the behaviour of others. Dyads received either oxytocin or a non-active placebo, intranasally. We show that in conditions where one dyad-member was tapping to another unresponsive dyad-member – i.e. one was following another who was leading/self-pacing – dyads given oxytocin were more synchronised than dyads given placebo. However, there was no effect when following a regular metronome or when both tappers were mutually adapting to each other. Furthermore, relative to their self-paced tapping partners, oxytocin followers were less variable than placebo followers. Our data suggests that oxytocin improves synchronisation to an unresponsive partner’s behaviour through a reduction in tapping-variability. Hence, oxytocin may facilitate social interaction by enhancing sensorimotor predictions supporting interpersonal synchronisation. The study thus provides novel perspectives on how neurobiological processes relate to socio-psychological behaviour and contributes to the growing evidence that synchronisation and prediction are central to social cognition.

Anti-tumor effects of peptide analogs targeting neuropeptide hormone receptors on mouse pheochromocytoma cells

Pheochromocytoma is a rare but potentially lethal chromaffin cell tumor with currently no effective treatment. Peptide hormone receptors are frequently overexpressed on endocrine tumor cells and can be specifically targeted by various anti-tumor peptide analogs. The present study carried out on mouse pheochromocytoma cells (MPCs) and a more aggressive mouse tumor tissue-derived (MTT) cell line revealed that these cells are characterized by pronounced expression of the somatostatin receptor 2 (sst2), growth hormone-releasing hormone (GHRH) receptor and the luteinizing hormone-releasing hormone (LHRH) receptor. We further demonstrated significant anti-tumor effects mediated by cytotoxic somatostatin analogs, AN-162 and AN-238, by LHRH antagonist, Cetrorelix, by the cytotoxic LHRH analog, AN-152, and by recently developed GHRH antagonist, MIA-602, on MPC and for AN-152 and MIA-602 on MTT cells. Studies of novel anti-tumor compounds on these mouse cell lines serve as an important basis for mouse models of metastatic pheochromocytoma, which we are currently establishing.

[Composite polymers--an amalgam substitute for deciduous tooth cavities?]

In this prospective clinical study, 29 class II restorations in deciduous teeth were placed in 17 patients using the recently developed compomer Dyract. The restorations were clinically and macrophotographically evaluated immediately after placement and after 6 months in situ. In addition, marginal adaptation and loss of substance were quantitated using replicas. Clinical and macrophotographical findings were excellent. Quantitative marginal analysis scored 92.5% "continuous margin" immediately after placement of the restorations and 95.4% after 6 months. Mean loss of substance at the margins of the restorations was 20.8 microns with a standard deviation of 64.6 microns. Providing that the positive results of this short term study are confirmed by long term data, Dyract may replace amalgam in deciduous teeth.