The thymus is a vital organ of the immune system that plays an essential role in thymocyte development and maturation. Thymic atrophy occurs with age (physiological thymic atrophy) or as a result of viral, bacterial, parasitic or fungal infection (pathological thymic atrophy). Thymic atrophy directly results in loss of thymocytes and/or destruction of the thymic architecture, and indirectly leads to a decrease in naïve T cells and limited T cell receptor diversity. Thus, it is important to recognize the causes and mechanisms that induce thymic atrophy. In this review, we highlight current progress in infection-associated pathogenic thymic atrophy and discuss its possible mechanisms. In addition, we discuss whether extracellular vesicles/exosomes could be potential carriers of pathogenic substances to the thymus, and potential drugs for the treatment of thymic atrophy. Having acknowledged that most current research is limited to serological aspects, we look forward to the possibility of extending future work regarding the impact of neural modulation on thymic atrophy.

BackgroundPrevious studies have reported that gut microbiota is associated with an increased risk of chronic kidney disease (CKD) progression. However, whether gut microbiota has a causal effect on the development of CKD has not been revealed. Thus, we aimed to analyze the potential causal effect of gut microbiota on the risk of CKD using mendelian randomization (MR) study.Materials and MethodsIndependent single nucleotide polymorphisms closely associated with 196 gut bacterial taxa (N = 18340) were identified as instrumental variables. Two-sample MR was performed to evaluate the causal effect of gut microbiota on CKD (N = 480698), including inverse-variance-weighted (IVW) method, weighted median method, MR-Egger, mode-based estimation and MR-PRESSO. The robustness of the estimation was tested by a series of sensitivity analyses including Cochran’s Q test, MR-Egger intercept analysis, leave-one-out analysis and funnel plot. Statistical powers were also calculated.ResultsThe genetically predicted higher abundance of order Desulfovibrionales was causally associated with an increased risk of CKD (odds ratio = 1.15, 95% confidence interval: 1.05-1.26; p = 0.0026). Besides, we also detected potential causalities between nine other taxa (Eubacterium eligens group, Desulfovibrionaceae, Ruminococcaceae UCG-002, Deltaproteobacteria, Lachnospiraceae UCG-010, Senegalimassilia, Peptostreptococcaceae, Alcaligenaceae and Ruminococcus torques group) and CKD (p < 0.05). No heterogeneity or pleiotropy was detected for significant estimates.ConclusionWe found that Desulfovibrionales and nine other taxa are associated with CKD, thus confirming that gut microbiota plays an important role in the pathogenesis of CKD. Our work also provides new potential indicators and targets for screening and prevention of CKD.

Cadmium (Cd) is a common heavy metal contaminant which seriously affects plant growth and environmental safety. Biochar, as an organic soil amendment, has been shown to effectively mitigate Cd damage to plants. To study the effectiveness of biochar on mitigating Cd stress, Mentha piperita ‘chocolate’ and Mentha spicata were used in a pot experiment of Cd stress with a CdCl2 solution (10 mg Kg−1), while a biochar suspension (0, 40, 80, and 160 g Kg−1) was applied to the soil. The effects of Cd on the growth, physiological and biochemical properties, and Cd content in plant tissues of both mint species were found to be significant. The application of 40 g Kg−1, 80 g Kg−1, 160 g Kg−1 biochar significantly alleviated Cd damage to both mint species, increased plant height, leaf length, leaf width, biomass, photosynthetic rate, transpiration rate, stomatal conductance, and chlorophyll content, and decreased antioxidant enzyme activities (including superoxide dismutase, catalase, peroxidase, and polyphenol oxidase) and non-enzymatic antioxidant content (including flavonoids and total phenols). Biochar effectively reduced the Cd uptake by plants and decreased the migration and transformation capacity of Cd in the soil–plant system. In addition, the available nitrogen (available N), available phosphorus (available P), available potassium (available K), and pH in the soil increased after biochar application compared to non-biochar amended soil. The addition of 160 g Kg−1 biochar was shown to have the best performance of the application rates in this experiment and may be considered as an effective way to reduce the damage caused by Cd contamination to M. piperita ‘chocolate’ and M. spicata.

Salicylic acid (SA) plays an important role in regulating salt stress tolerance in plants. However, there are no studies on the effect of exogenous SA on Saponaria officinalis under salt stress. To study the effectiveness of SA on mitigating salt stress, S. officinalis were used in a pot experiment of salt stress simulated with an NaCl solution (100, 200, and 300 mmol L−1), while an SA solution (0, 0.2, 0.4, 0.6, 0.8, 1.0 mmol L−1) was sprayed on leaves. Under salt stress, spraying SA caused an increase in the salt damage index, electrolyte leakage, and a reduction in malondialdehyde and Na+ content, but an increase in the rate of photosynthesis, chlorophyll, soluble sugar, soluble protein, free proline, K+, Mg2+, Ca2+ content, the K+/Na+ ratio, superoxide dismutase, peroxidase, catalase, ascorbate peroxidase activity, and the comprehensive score. The results show that SA improves the salt tolerance capacity of S. officinalis by modulating its photosynthetic rate, osmoprotectants, antioxidant levels, and ion homeostasis. However, the effectiveness of SA was not linearly related to its concentration. In summary, our findings reveal the protective roles of SA against salinity in S. officinalis and suggest that the use of 0.6 mmol L−1 of SA in salt stress conditions could be an effective approach to reduce the damage caused by saline soil in S. officinalis.

What is already known on this subject?• Salicylic acid plays a key role in the plant response to environmental stress, which can improve the growth and development of a variety of plants under salt stress, and has the potential to become an effective measure to manage plant salt tolerance.• Salicylic acid can indeed improve tolerance of Hosta ensata to salt stress, and this effect may be achieved through regulation of photosynthetic system, osmoregulation system and antioxidant system.What is the expected impact on horticulture?• The results of this study can prove that the application of exogenous salicylic acid is an effective measure to improve the salt tolerance of Hosta ensata, and can provide a reference for the application of salicylic acid in horticultural plant cultivation.