Subsequent drought and re-watering events cause a shift in productivity and nutritive value of alfalfa and hybrid fescue plant

Global climate change leads to increasing frequency of droughts, threatening the productivity and quality of forage plants. Therefore, this glasshouse experiment was conducted to investigate the effects of reoccurring droughts on productivity and nutritive value of alfalfa and hybrid fescue plants. Starting from 63 days after sowing, seedlings of plants were exposed to double drought-recovery treatments, each separate period lasting for 1 week. At the end of each treatment, growth of above- and below-ground dry weight, lipid peroxidation, total antioxidative capacity, content of polyphenols, soluble and insoluble carbohydrates and proteins, as well as elemental composition of shoots were investigated. The findings confirmed our hypothesis, as growth of both plant species were mostly insignificantly affected by subsequent drought events. Whereas effect on leave redox homeostasis and plant nutritive value was much stronger, highly depending on both plant species and the order of stress event. We found significant drought-induced increase in the content of water-soluble carbohydrates (WSCs), starch, soluble and insoluble proteins, and polyphenols. Water shortage tended to decrease and increase the content of most macro- and microelements in alfalfa and fescue, respectively. These effects were reversed by re-watering with several exceptions, such as constant reduction of Ca content in alfalfa. To conclude, alfalfa was found to be more sensitive than fescue to the first drought, but able to recover after both stress events. The second drought-initiated prolonged accumulation of WSC implies a shift in plants metabolism towards increased resistance and herewith nutritive value with respect to soluble sugars.     

Group definition and the idea of ‘race’ in modern China (1793–1949)

This article briefly traces the history of the idea of ‘race’ in modern China. From the nineteenth century onwards, an increasing insistence on biological differences between the ingroup and the outgroup came to contrast with traditional Chinese culturally oriented ethnocentrism. This transition from cultural universalism to racial exclusiveness started during the middle of the nineteenth century and was completed in the 1920s. Four main historical phases can be distinguished: (1) the heightening of a racial consciousness from the Opium War (1842) to the Sino‐Japanese War (1894–5); (2) the emergence of the idea of a yellow race, opposed to a superior white race in its struggle for control over the other races (1895–1902); (3) the development of a nationalistic vision of race, narrowed down to the Han Chinese, perceived as a homogeneous biological unit descended from the Yellow Emperor (1902–15); and (4) the infusion of science into a racial rhetoric that emphasized the original purity, genetic foundation and biological uniqueness of the ingroup in its interpretation of outgroups (1915–49).     

In Vitro Evaluation of Spider Silk Meshes as a Potential Biomaterial for Bladder Reconstruction

Reconstruction of the bladder by means of both natural and synthetic materials remains a challenge due to severe adverse effects such as mechanical failure. Here we investigate the application of spider major ampullate gland-derived dragline silk from the Nephila edulis spider, a natural biomaterial with outstanding mechanical properties and a slow degradation rate, as a potential scaffold for bladder reconstruction by studying the cellular response of primary bladder cells to this biomaterial. We demonstrate that spider silk without any additional biological coating supports adhesion and growth of primary human urothelial cells (HUCs), which are multipotent bladder cells able to differentiate into the various epithelial layers of the bladder. HUCs cultured on spider silk did not show significant changes in the expression of various epithelial-to-mesenchymal transition and fibrosis associated genes, and demonstrated only slight reduction in the expression of adhesion and cellular differentiation genes. Furthermore, flow cytometric analysis showed that most of the silk-exposed HUCs maintain an undifferentiated immunophenotype. These results demonstrate that spider silk from the Nephila edulis spider supports adhesion, survival and growth of HUCs without significantly altering their cellular properties making this type of material a suitable candidate for being tested in pre-clinical models for bladder reconstruction.     

Quantifying antimicrobial resistance at veal calf farms

This study was performed to determine a sampling strategy to quantify the prevalence of antimicrobial resistance on veal calf farms, based on the variation in antimicrobial resistance within and between calves on five farms. Faecal samples from 50 healthy calves (10 calves/farm) were collected. From each individual sample and one pooled faecal sample per farm, 90 selected Escherichia coli isolates were tested for their resistance against 25 mg/L amoxicillin, 25 mg/L tetracycline, 0.5 mg/L cefotaxime, 0.125 mg/L ciprofloxacin and 8/152 mg/L trimethoprim/sulfamethoxazole (tmp/s) by replica plating. From each faecal sample another 10 selected E. coli isolates were tested for their resistance by broth microdilution as a reference. Logistic regression analysis was performed to compare the odds of testing an isolate resistant between both test methods (replica plating vs. broth microdilution) and to evaluate the effect of pooling faecal samples. Bootstrap analysis was used to investigate the precision of the estimated prevalence of resistance to each antimicrobial obtained by several simulated sampling strategies. Replica plating showed similar odds of E. coli isolates tested resistant compared to broth microdilution, except for ciprofloxacin (OR 0.29, p≤0.05). Pooled samples showed in general lower odds of an isolate being resistant compared to individual samples, although these differences were not significant. Bootstrap analysis showed that within each antimicrobial the various compositions of a pooled sample provided consistent estimates for the mean proportion of resistant isolates. Sampling strategies should be based on the variation in resistance among isolates within faecal samples and between faecal samples, which may vary by antimicrobial. In our study, the optimal sampling strategy from the perspective of precision of the estimated levels of resistance and practicality consists of a pooled faecal sample from 20 individual animals, of which 90 isolates are tested for their susceptibility by replica plating.     

USEtox fate and ecotoxicity factors for comparative assessment of toxic emissions in life cycle analysis: sensitivity to key chemical properties

Purpose  

The USEtox model was developed in a scientific consensus process involving comparison of and harmonization between existing environmental multimedia fate models. USEtox quantitatively models the continuum from chemical emission to freshwater ecosystem toxicity via chemical-specific characterization factors (CFs) for Life Cycle Impact Assessment (LCIA). This work provides understanding of the key mechanisms and chemical parameters influencing fate in the environment and impact on aquatic ecosystems.