Nitrate and phosphate availability and distribution have different effects on root system architecture of Arabidopsis

Plant root systems can respond to nutrient availability and distribution by changing the three-dimensional deployment of their roots: their root system architecture (RSA). We have compared RSA in homogeneous and heterogeneous nitrate and phosphate supply in Arabidopsis. Changes in nitrate and phosphate availability were found to have contrasting effects on primary root length and lateral root density, but similar effects on lateral root length. Relative to shoot dry weight (DW), primary root length decreased with increasing nitrate availability, while it increased with increasing phosphate supply. Lateral root density remained constant across a range of nitrate supplies, but decreased with increasing phosphate supply. In contrast, lateral root elongation was suppressed both by high nitrate and high phosphate supplies. Local supplies of high nitrate or phosphate in a patch also had different effects. Primary root growth was not affected by a high nitrate patch, but growth through a high phosphate patch reduced primary root growth after the root left the patch. A high nitrate patch induced an increase in lateral root density in the patch, whereas lateral root density was unaffected by a high phosphate patch. However, both phosphate- and nitrate-rich patches induced lateral root elongation in the patch and suppressed it outside the patch. This co-ordinated response of lateral roots also occurs in soil-grown plants exposed to a nutrient-rich patch. The auxin-resistant mutants axr1, axr4 and aux1 all showed the wild-type lateral root elongation responses to a nitrate-rich patch, suggesting that auxin is not required for this response

Root system architecture determines fitness in an Arabidopsis mutant in competition for immobile phosphate ions but not for nitrate ions

Plant root systems often have complex branching patterns. Models indicate that a complex architecture is only required for the acquisition of immobile resources, such as phosphate; mobile ions, notably nitrate, can be effectively taken up by very restricted root systems. We have tested this prediction using the axr4 mutation of Arabidopsis thaliana, the principal phenotypic effect of which is to reduce the number of lateral roots. Arabidopsis thaliana is not a host for mycorrhizal fungi and so acquires all its nutrients through the root system. In both a pot experiment and a field experiment conducted under natural conditions for A. thaliana, we found that only phosphate, and not nitrate, affected the fitness of the mutant relative to the isogenic wild-type line, Columbia. These results confirm model predictions and have implications both for the evolution of complex root systems and for the design of efficient root systems for crops

Blood lead levels in 2018/2019 compared to 1987/1988 in the German population-based KORA study

INTRODUCTION: Lead exposure remains of continuing concern due to its known and suspected impacts on human health and has been designated as a priority substance for investigation in human biomonitoring studies by the EU. The aims of this study were to measure blood lead levels (BLL) in a population based cohort of middle-aged individuals without major current exposures to lead, and to compare these to historical blood lead levels obtained thirty years earlier. METHODS: The population-based KORA study from 1984 to 2001 included inhabitants of the Augsburg Region, Germany. During 2018 to 2019, a subsample of these participants (KORA-Fit) was invited for interview regarding demographic and lifestyle factors, physical examination and blood withdrawal. Blood samples were stored at -80C prior to measurement of BLL via graphite furnace atomic absorption spectroscopy (GF-AAS). Descriptive and multivariable analyses were performed. RESULTS: BLLs were measured in 3033 eligible persons aged 54 to 73, establishing a geometric mean (GM) BLL of 24.8 μg/l in 2018/19. Of these, 555 (18%) had BLL above proposed 95th percentile reference values of the German Environment Agency. Only small differences were found in BLL stratified by sociodemographic categories, however regular smokers had higher GM BLL (26.1 μg/l) compared to never smokers (23.7 μg/l), and an increasing BLL with increased wine consumption was noted. For 556 individuals, BLLs (GM: 54.0 μg/l) reduced by 35% in men and 50% in women compared to levels in 1987/88 with only 1.4% of individuals having an unchanged or increased BLL. DISCUSSION: KORA-Fit provided contemporary normative data for BLL in a Western European population without major current sources of lead exposure. Mean BLLs have fallen since the 1980s using historical BLL data which is likely linked to the ban of leaded gasoline. Nevertheless, BLLs in this population remain elevated at levels associated with morbidity and mortality

Validation of the 30-Year Framingham Risk Score in a German Population-Based Cohort

The Framingham Risk Score to predict 30-year risk (FRS30y) of cardiovascular disease (CVD) constitutes an important tool for long-term risk prediction. However, due to its complex statistical properties and the paucity of large population-based cohorts with appropriate data, validation of the FRS30y is lacking. A population-based cohort from Southern Germany (N = 3110, 1516 (48.7%) women) was followed up for a median time of 29.5 [18.7, 31.2] years. Discrimination and calibration were assessed for the original, recalibrated and refitted FRS30y version. During follow up, 620 incident CVD events (214 in women) occurred. The FRS30y showed adequate discrimination (original and recalibrated version: Area under the curve (AUC): 78.4 for women and 74.9 for men) but overestimated actual CVD risk (original version: discordance 45.4% for women and 37.3% for men, recalibrated version: 37.6% and 28.6%, respectively). Refitting showed substantial improvement in neither discrimination nor calibration. The performance of FRS30y is adequate for long-term CVD risk prediction and could serve as an important tool in risk communication, especially for younger audiences

automated detection of non-wear time in comparison to diary information

Estimation of physical activity using 24 h-accelerometry requires detection of accelerometer non-wear time (NWT). It is common practice to define NWT as periods >60 minutes of consecutive zero-accelerations, but this algorithm was originally developed for waking hours only and its applicability to 24 h-accelerometry is unclear. We investigated sensitivity and specificity of different algorithms to detect NWT in 24 h-accelerometry compared to diary in 47 ActivE and 559 KORA participants. NWT was determined with algorithms >60, >90, >120, >150, or >180 minutes of consecutive zero-counts. Overall, 9.1% (ActivE) and 15.4% (KORA) of reported NWT was >60 minutes. Sensitivity and specificity were lowest for the 60-min algorithm in ActivE (0.72 and 0.00) and KORA (0.64 and 0.08), and highest for the 180-min algorithm in ActivE (0.88 and 0.92) and for the 120-min algorithm in KORA (0.76 and 0.74). Nevertheless, when applying these last two algorithms, the overlap of accelerometry with any diary based NWT minutes was around 20% only. In conclusion, only a small proportion of NWT is >60 minutes. The 60-min algorithm is less suitable for NWT detection in 24 h-accelerometry because of low sensitivity, specificity, and small overlap with reported NWT minutes. Longer algorithms perform better but detect lower proportions of reported NWT

A Deep Learning Algorithm for Prediction of Age-Related Eye Disease Study Severity Scale for Age-Related Macular Degeneration from Color Fundus Photography

Acknowledgments The authors thank the Age-Related Eye Disease Study participants and the Age-Related Eye Disease Study Research Group for their valuable contribution to this research, and all study participants for contributing to the Cooperative Health Research in the Region of Augsburg study.Peer reviewedPublisher PD