The role of HIG1/MYB51 in the regulation of indolic glucosinolate biosynthesis

Glucosinolates are amino-acid derived plant secondary metabolites found mainly in Brassicaceae, including the model plant Arabidopsis thaliana. Due to their role in plant defence and their cancer-preventive properties in human nutrition, they have gained increasing interest over the last years. This study presents the characterisation of the activation-tagging mutant HIG1-1D, which displays a high indolic glucosinolate phenotype, caused by an activation of the R2R3-type MYB transcription factor HIG1/MYB51. A positive correlation between HIG1/MYB51 transcription and the accumulation of indolic glucosinolates could be confirmed in gain and loss-of-function mutants. HIG1/MYB51 expression overlaps with sites of indolic glucosinolate biosynthesis and the expression of biosynthesis genes, which are activated by HIG1/MYB51 in trans. Unlike previously characterised mutants affected in indolic glucosinolate biosynthesis, HIG1-1D displays only minor effects on auxin biosynthesis. However, a role of HIG1/MYB51 in the biotic stress response of A. thaliana appears likely, due to the mechano-sensitive expression of HIG1/MYB51 along with an increased resistance of HIG1-1D plants against a generalist herbivore. Yeast-two-hybrid screening allowed identifying the interaction of HIG1/MYB51 with ATR2/bHLH05, a putative regulator of tryptophan and indolic glucosinolate biosynthesis. Therefore, HIG1/MYB51 appears to be part of a complex network controlling indolic glucosinolate biosynthesis

Driving forces of Antarctic krill abundance

Antarctic krill, crucial to the Southern Ocean ecosystem and a vital fisheries resource, is endangered by climate change. Identifying drivers of krill biomass is therefore essential for determining catch limits and designating protection zones. We present a modeling approach to pinpointing effects of sea surface temperature, ice cover, chlorophyll levels, climate indices, and intraspecific competition. Our study reveals that larval recruitment is driven by both competition among age classes and chlorophyll levels. In addition, while milder ice and temperature in spring and summer favor reproduction and early larval survival, both larvae and juveniles strongly benefit from heavier ice and colder temperatures in winter. We conclude that omitting top-down control of resources by krill is only acceptable for retrospective or single-year prognostic models that use field chlorophyll data but that incorporating intraspecific competition is essential for longer-term forecasts. Our findings can guide future krill modeling strategies, reinforcing the sustainability of this keystone species

Opposing roles of σB and σB-controlled SpoVG in the global regulation of esxA in Staphylococcus aureus

BACKGROUND: The production of virulence factors in Staphylococcus aureus is tightly controlled by a complex web of interacting regulators. EsxA is one of the virulence factors that are excreted by the specialized, type VII-like Ess secretion system of S. aureus. The esxA gene is part of the σB-dependent SpoVG subregulon. However, the mode of action of SpoVG and its impact on other global regulators acting on esxA transcription is as yet unknown. RESULTS: We demonstrate that the transcription of esxA is controlled by a regulatory cascade involving downstream σB-dependent regulatory elements, including the staphylococcal accessory regulator SarA, the ArlRS two-component system and SpoVG. The esxA gene, preceding the ess gene cluster, was shown to form a monocistronic transcript that is driven by a σA promoter, whereas a putative σB promoter identified upstream of the σA promoter was shown to be inactive. Transcription of esxA was strongly upregulated upon either sarA or sigB inactivation, but decreased in agr, arlR and spoVG single mutants, suggesting that agr, ArlR and SpoVG are able to increase esxA transcription and relieve the repressing effect of the σB-controlled SarA on esxA. CONCLUSION: SpoVG is a σB-dependent element that fine-tunes the expression of esxA by counteracting the σB-induced repressing activity of the transcriptional regulator SarA and activates esxA transcription

Feasibility, effectiveness and safety of the self-management intervention deprexis in routine medical care: Results of an uncontrolled observational study

Introduction: Numerous RCTs have demonstrated the effectiveness of internet-based self-management interventions (SMIs) in the treatment of depressive symptoms. These studíes often recruit outside routine clinical practice. For the present study, we investigated the feasibility, effectiveness and safety of an SMI (deprexis) in routine medical care using a non-interventional design. Methods: A total of 104 patients with a depressive disorder (60.58% female, mean age 45.82 yrs) were recruited in 25 outpatient practices in Germany (mostly psychiatric practices, n = 16). They received 12 week access to the SMI in addition to their usual care (76.0% took concomitant antidepressant medication). Guidance could optionally be offered by the treating physician. The effectiveness of the intervention was assessed using the clinician-rated short version of the Montgomery Asberg-Depression Scale (svMADRS) and the Patient Health Questionnaire (PHQ-9), a self-rating for depressive symptoms. Outcomes were assessed at baseline as well as at weeks 3, 6, 9 and 12. Results: Most patients reported using the intervention at least once (n = 87, 83.6%), among these users the mean number of sessions was 18.05 (SD = 11.33). Only a minority of patients received the guided version of the intervention (n = 7, 8.0%). The severity of depressive symptoms decreased significantly over the observation period from 29.72 (SD = 10.03) to 15.73 (SD = 9.74) for the svMADRS (Cohen's d = 1.42, 95% CI 0.08–2.76) and from 15.20 (SD = 5.03) to 8.77 (SD = 5.03) for the PHQ-9 (d = 1.29, 95% CI 0.60–1.97). Discussion: The size of the pre-post effect on depressive symptoms observed in this study is comparable to the pre-post effect size reported in an RCT using the same intervention in patients suffering from depressive symptoms of the same severity. Limitations of this study include the lack of a control group and the fact that the recruitment rate was far lower than expected. Conclusion: This non-interventional study conducted in outpatient practices confirms results from numerous RCTs. Taken together, these data show that deprexis can be used effectively and safely in the routine care of depressed outpatients

The impact of salps (Salpa thompsoni) on the Antarctic krill population (Euphausia superba): an individual-based modelling study

Krill (Euphausia superba) and salps (Salpa thompsoni) are key macrozooplankton grazers in the Southern Ocean ecosystem. However, due to differing habitat requirements, both species previously exhibited little spatial overlap. With ongoing climate change-induced seawater temperature increase and regional sea ice loss, salps can now extend their spatial distribution into historically krill-dominated areas and increase rapidly due to asexual reproduction when environmental conditions are favorable. Understanding the potential effects on krill is crucial, since krill is a species of exceptional trophic significance in the Southern Ocean food web. Negative impacts on krill could trigger cascading effects on its predators and prey. To address this question, we combined two individual-based models on salps and krill, which describe the whole life cycle of salp individuals and the dynamic energy budget of individual krill. The resulting new model PEKRIS (PErformance of KRIll vs. Salps) simulates a krill population for 100 years under varying chlorophyll-a concentrations in the presence or absence of salps. All of the investigated krill population properties (abundance, mean length, and yearly egg production) were significantly impacted by the presence of salps. On the other hand, salp density was not impacted if krill were present. The medians of krill population properties deviated during variable maximum chlorophyll-a density per year when salps were introduced by − 99.9% (− 234 individuals per 1000 m3) for krill density, − 100% (− 22,062 eggs per 1000 m3) for krill eggs and − 0.9% (− 0.3 mm) for mean length of krill. If both species compete for the same food resource in a closed space, salps seem to inhibit krill populations. Further simulation studies should investigate whether this effect prevails if different phytoplankton sizes and consumption preferences of krill are implemented. Furthermore, direct predation of the two species or consumption of krill fecal pellets by salps could change the impact size of the food competition

Blooms of a key grazer in the Southern Ocean – An individual-based model of Salpa thompsoni

The Southern Ocean near the Western Antarctic Peninsula (WAP) is strongly affected by climate change resulting in warmer air temperature, accompanied with reduced sea ice coverage, increased sea water temperature and potential changes in the abundances of two key grazer species Salpa thompsoni (salp) and Euphausia superba (Antarctic krill). While salp abundance is hypothesized to increase, krill abundance is hypothesized to decline with dramatic consequences for the entire food web of the Southern Ocean. A better understanding of the biotic interaction between krill and salps and their population dynamics is thus crucial. However, the life cycle of salps is complicated and barely understood. Therefore, we have developed an individual-based model describing the whole life cycle to better understand the population dynamics of salps and the conditions for blooms. The model has been used to explore if and under what conditions the empirical pattern of large variability in observed salp abundances at the WAP, generated by the long-term data of the US Antarctic Marine Living Resources Program (AMLR) can emerge from a small seeding population. The model reproduced this empirical pattern if daily growth rates of oozoids were higher than previously reported for the WAP (mean growth rate for oozoids ~ 1 mm d−1) and if growth rates of blastozooids were lower (mean growth rate ~ 0.2 mm d−1). The model suggests that a prerequisite for local salp blooms requires a small founding population in early spring. With climate change it has been suggested that more frequent and earlier transport of salps into the WAP or winter survival will occur. Hence, the risk of salp blooms in the WAP is likely to substantially increase. These findings highlight the importance for an improved quantitative understanding of how primary production and the southward advection of salps will be impacted by climate change

The position of the Rupelian/Chattian boundary in the southern Upper Rhine Graben based on new records of microfossils

This study analyses the regressive phase of the marine Froidefontaine Subgroup and the subsequent fluvio-lacustrine Niederroedern formation in the southern Upper Rhine Graben during the Late Rupelian and the position of the Rupelian/Chattian boundary. The study is based on the sedimentary record and several microfossil groups from two boreholes, with a focus on new records of fish otoliths, Bolboforma and Charophyta. The biostratigraphic evaluation of these groups provides evidence for a position of the Rupelian/Chattian boundary within the upper Niederroedern Formation. This is contrary to the results from a previous sedimentological approach, which places the boundary at the base of the Niederroedern Formation. The fish fauna indicates a biogeographic relation to southern France, the Molasse Basin of Switzerland and southern German

A Comprehensive Image-based Phenomic Analysis Reveals the Complex Genetic Architecture of Shoot Growth Dynamics in Rice (\u3ci\u3eOryza sativa\u3c/i\u3e)

Early vigor is an important trait for many rice (Oryza sativa L.)- growing environments. However, genetic characterization and improvement for early vigor is hindered by the temporal nature of the trait and strong genotype × environment effects. We explored the genetic architecture of shoot growth dynamics during the early and active tillering stages by applying a functional modeling and genomewide association (GWAS) mapping approach on a diversity panel of ~360 rice accessions. Multiple loci with small effects on shoot growth trajectory were identified, indicating a complex polygenic architecture. Natural variation for shoot growth dynamics was assessed in a subset of 31 accessions using RNA sequencing and hormone quantification. These analyses yielded a gibberellic acid (GA) catabolic gene, OsGA2ox7, which could influence GA levels to regulate vigor in the early tillering stage. Given the complex genetic architecture of shoot growth dynamics, the potential of genomic selection (GS) for improving early vigor was explored using all 36,901 single-nucleotide polymorphisms (SNPs) as well as several subsets of the most significant SNPs from GWAS. Shoot growth trajectories could be predicted with reasonable accuracy using the 50 most significant SNPs from GWAS (0.37–0.53); however, the accuracy of prediction was improved by including more markers, which indicates that GS may be an effective strategy for improving shoot growth dynamics during the vegetative growth stage. This study provides insights into the complex genetic architecture and molecular mechanisms underlying early shoot growth dynamics and provides a foundation for improving this complex trait in rice