Drought shortens subtropical understory growing season by advancing leaf senescence.

Subtropical forests, recognized for their intricate vertical canopy stratification, exhibit high resistance to extreme drought. However, the response of leaf phenology to drought in the species-rich understory remains poorly understood. In this study, we constructed a digital camera system, amassing over 360,000 images through a 70% throughfall exclusion experiment, to explore the drought response of understory leaf phenology. The results revealed a significant advancement in understory leaf senescence phenology under drought, with 11.75 and 15.76 days for the start and end of the leaf-falling event, respectively. Pre-season temperature primarily regulated leaf development phenology, whereas soil water dominated the variability in leaf senescence phenology. Under drought conditions, temperature sensitivities for the end of leaf emergence decreased from -13.72 to -11.06 days °C-1, with insignificance observed for the start of leaf emergence. Consequently, drought treatment shortened both the length of the growing season (15.69 days) and the peak growth season (9.80 days) for understory plants. Moreover, this study identified diverse responses among intraspecies and interspecies to drought, particularly during the leaf development phase. These findings underscore the pivotal role of water availability in shaping understory phenology patterns, especially in subtropical forests.

Scurvy in a young man: a rare case report.

Scurvy, resulting from vitamin C deficiency, has nonspecific constitutional symptoms, including weakness, malaise, and fatigue. It is frequently misdiagnosed due to the lack of specific clinical manifestations. Although there are sporadic cases of scurvy currently reported in children, scurvy in young people is seldom encountered. Here, we report on a 25-year-old male patient without any underlying conditions who presented with severe pain and ecchymoses of both lower extremities. He was diagnosed with scurvy due to a long history of staying indoors and inadequate intake of fruits or vegetables.

Causal relationship between asthma and ulcerative colitis and the mediating role of interleukin-18: a bidirectional Mendelian study and mediation analysis.

Objective: Numerous observational investigations have documented a correlation between asthma and ulcerative colitis(UC). In this Mendelian Randomization (MR) study, we utilized extensive summary data from Genome-Wide Association Studies (GWAS) to further estimate the association between adult-onset asthma and the risk of UC, and to investigate the role of Interleukin-18 (IL-18) as a potential mediator. Materials and methods: A two-step, two-sample MR study was conducted through mediation analysis. For this study, we employed a two-sample MR analysis using the inverse variance-weighted (IVW), weighted median, weighted mode, and MR-Egger regression techniques. We utilized publicly accessible summary statistics from a GWAS meta-analysis of adult-onset asthma in the UK Biobank (n=327,253; cases=26,582; controls=300,671) as the exposure factor. The outcomes were derived from GWAS data of individuals with European ancestry (n=26,405; cases=6,687; controls=19,718). GWAS data for IL-18 were obtained from individuals of European ancestry (n=9,785,222; cases=3,636; controls=9,781,586). Results: The MR analysis indicates that adult-onset asthma is associated with an increased risk of UC, with an odds ratio (OR) of 1.019 (95% CI 1.001-1.045, P=0.006). However, there is no strong evidence to suggest that UC significantly impacts the risk of adult-onset asthma. IL-18 may act as a potential mediator in the causal relationship between adult-onset asthma and UC, with a mediation proportion of 3.9% (95% CI, 0.6%-6.9%). Conclusion: In summary, our study established a causal relationship between asthma and UC, in which IL-18 contributes to a small extent. However, the primary factors underlying the influence of asthma on UC remain unclear. Future research should focus on identifying other potential mediators. In clinical practice, it is important to pay greater attention to intestinal lesions in patients with asthma.

Plant photosynthetic overcompensation under nocturnal warming: lack of evidence in subtropical evergreen trees.

BACKGROUND AND AIMS: Increased plant photosynthesis under nocturnal warming is a negative feedback mechanism to overcompensate for night-time carbon loss to mitigate climate warming. This photosynthetic overcompensation effect has been observed in dry deciduous ecosystems but whether it exists in subtropical wet forest trees is unclear. METHODS: Two subtropical evergreen tree species (Schima superba and Castanopsis sclerophylla) were grown in a greenhouse and exposed to ambient and elevated night-time temperature. The occurrence of the photosynthetic overcompensation effect was determined by measuring daytime and night-time leaf gas exchange and non-structural carbohydrate (NSC) concentration. KEY RESULTS: A reduction in leaf photosynthesis for both species and an absence of persistent photosynthetic overcompensation were observed. The photosynthetic overcompensation effect was transient in S. superba due to respiratory acclimation and stomatal limitation. For S. superba, nocturnal warming resulted in insufficient changes in night-time respiration and NSC concentration to stimulate overcompensation and inhibited leaf stomatal conductance by increasing the leaf-to-air vapour pressure deficit. CONCLUSIONS: The results indicate that leaf stomatal conductance is important for the photosynthetic overcompensation effect in different tree species. The photosynthetic overcompensation effect under nocturnal warming may be a transient occurrence rather than a persistent mechanism in subtropical forest ecosystems.

Soil phosphorus drives plant trait variations in a mature subtropical forest.

Earth system models are implementing soil phosphorus dynamic and plant functional traits to predict functional changes in global forests. However, the linkage between soil phosphorus and plant traits lacks empirical evidence, especially in mature forests. Here, we examined the soil phosphorus constraint on plant functional traits in a mature subtropical forest based on observations of 9943 individuals from 90 species in a 5-ha forest dynamic plot and 405 individuals from 15 species in an adjacent 10-year nutrient-addition experiment. We first confirmed a pervasive phosphorus limitation on subtropical tree growth based on leaf N:P ratios. Then, we found that soil phosphorus dominated multidimensional trait variations in the 5-ha forest dynamic plot. Soil phosphorus content explained 44% and 53% of the variance in the traits defining the main functional space across species and communities, respectively. Lastly, we found much stronger phosphorus effects on most plant functional traits than nitrogen at both species and community levels in the 10-year nutrient-addition experiment. This study provides evidence for the consistent pattern of soil phosphorus constraint on plant trait variations between the species and community levels in a mature evergreen broadleaf forest in the East Asian monsoon region. These findings shed light on the predominant role of soil phosphorus on plant functional trait variations in mature subtropical forests, providing new insights for models to incorporate soil phosphorus constraint in predicting future vegetation dynamics.

Nocturnal warming accelerates drought-induced seedling mortality of two evergreen tree species.

Extreme drought is one of the key climatic drivers of tree mortality on a global scale. However, it remains unclear whether the drought-induced tree mortality will increase under nocturnal climate warming. Here we exposed seedlings of two wide-ranging subtropical tree species, Castanopsis sclerophylla and Schima superba, with contrasting stomatal regulation strategies to prolonged drought under ambient and elevated night-time temperature by 2 °C. We quantified the seedling survival time since drought treatment by measuring multiple leaf traits such as leaf gas exchange, predawn leaf water potential and water-use efficiency. The results showed that all seedlings in the ambient temperature died within 180 days and 167 days of drought for C. sclerophylla and S. superba, respectively. Night warming significantly shortened the survival time of C. sclerophylla, by 31 days, and S. superba by 28 days, under the drought treatment. A survival analysis further showed that seedlings under night warming suffered a 1.6 times greater mortality risk than those under ambient temperature. Further analyses revealed that night warming suppressed net leaf carbon gain in both species by increasing the nocturnal respiratory rate of S. superba across the first 120 days of drought and decreasing the photosynthetic rate of both species generally after 46 days of drought. These effects on net carbon gain were more pronounced in S. superba than C. sclerophylla. After 60 days of drought, night warming decreased the predawn leaf water potential and leaf water-use efficiency of C. sclerophylla but not S. superba. These contrasting responses are partially due to variations in stomatal control between the two species. These findings suggest that stomatal traits can regulate the response of leaf gas exchange and plant water-use to nocturnal warming during drought. This study indicates that nocturnal warming can accelerate tree mortality during drought. Night warming accelerates the mortality of two subtropical seedlings under drought.Night warming differently affects the drought response of leaf gas exchange and plant water-use between the two species due to species-specific stomatal morphological traits.Carbon metabolism changes and hydraulic damage play differential roles in driving night-warming impacts on the drought-induced mortality between the two species.

Metformin Affects Gut Microbiota Composition and Diversity Associated with Amelioration of Dextran Sulfate Sodium-Induced Colitis in Mice.

Background: Inflammatory bowel disease (IBD) is an increasingly common and globally emergent immune-mediated disorder. The etiology of IBD is complex, involving multiple factors such as immune dysregulation, environmental factors, genetic mutations, and microbiota dysbiosis, exacerbated by a lack of effective clinical therapies. Recently, studies hypothesized that dysbiosis of intestinal flora might participate in the onset of IBD. Metformin is widely used to treat type 2 diabetes and has shown beneficial effects in mouse models of IBD, although its underlying mechanisms remain poorly understood. Accumulating studies found that metformin shows beneficial effects for diabetes by affecting microbiota composition. This study explores possible regulatory effects of metformin on intestinal microecology during treatment for IBD. Methods: Inflammation was induced using 3% Dextran Sulfate Sodium (DSS) solution to generate mice models of IBD. Metformin treatments were assayed by measuring body weights and colon lengths of mice and H&E staining to observe histological effects on colon tissue structures. Changes in bacterial community composition and diversity-related to IBD and metformin treatment were assessed by high-throughput metagenomic sequencing analysis. Results: Metformin administration significantly ameliorated body weight loss, inhibited colon shrinking, and contributed to preserving the integrity of colon histological structures. The gut microbiota profiles revealed that the biodiversity of intestinal flora lost during inflammation was restored under metformin treatment. Metformin administration was also associated with decreased pathogenic Escherichia shigella and increased abundance of Lactobacillus and Akkermansia. Conclusion: Metformin appears to induce anti-inflammatory effects, thus ameliorating colitis symptoms, concurrent with enrichment for beneficial taxa and restored microbial diversity, suggesting a viable strategy against IBD.

A case report of the pancreatic and periampullary metastases of renal cell carcinoma, 17 years after surgery.

Renal cell carcinoma (RCC) is the most common renal tumor with a high incidence in the recent decade. Generally, an RCC metastasis mainly occurs via hematogenous and lymphomatous routes. Even though RCC has a potential to metastasize to almost any site, metastasis to the pancreas and duodenal ampulla is a rare event. In this study, we describe a case of pancreatic and periampullary metastatic renal cell carcinoma, which recurred 17 years after surgery. The patient admitted to hospital for severe symptoms of jaundice and skin pruritus after removal of the primary tumor for 17 years. Computer tomography angiography (CTA) scan and endoscopy showed pancreatic and duodenal ampullary metastasis. Finally, it confirmed by histopathologic examination. After some symptomatic treatment has been given the patient remained alive. However, intermittent hematochezia along with these metastatic lesions continue to occur until now as observed during the annual follow-up appointments. This study concludes that metastatic involvement of the pancreas and other organs should be suspected in any patient with a history of an RCC who does not manifest any typical symptom even after more than 10 years of RCC resection. In the case of abnormal symptoms and examination results after several years of RCC surgery, attention should be paid to provide immediate treatment.

PlantNE: a global database of plant biomass from nitrogen-addition experiments.

The growth of terrestrial plants and the production of terrestrial ecosystems are highly dependent on the availability of nitrogen (N). During the past decades, the rate of global atmospheric N deposition has shown an increasing trend, greatly relieving N limitation on terrestrial plant growth. Thus, whether and how plant biomass will respond to increasing N deposition in the future is particularly important with regard to the function of terrestrial ecosystems. The N-addition experiment is a major approach to study the ecological responses of plant species occurring in natural terrestrial ecosystems under N enrichment. In recent decades, many N-addition experiments have been conducted across various plant functional types and terrestrial ecosystems, but their data on plant biomass have yet to be synthesized into a single database. Here, we present an open-access database of measured plant biomass in N-addition experiments (PlantNE) collected from available publications in Web of Science. The reported mean, standard deviation, and sample size of plant biomass in both control and treatment plots were collected in each publication. As a result, the PlantNE database records 519 plant species from 4,599 observations in 348 published studies. It covers a wide geographical range (54.75° S-69.66° N; 157.80° W-175.30°E) and a broad natural climate zone (-10°C to 27.6°C; 94-7,000 mm) over the past three decades (1982-2018). Information related to the experimental site (i.e., latitude, longitude, country, ecosystem, experimental condition, temperature, and precipitation), biotic factors (i.e., species, plant category, plant age, planting pattern, and plant part), and N treatment (i.e., N dose, treatment interval and duration, and N addition with other treatments) is included in this database. We expect that the PlantNE database can contribute to the understanding of ecosystem productivity and biodiversity under increasing atmospheric N deposition and provide empirical data for model studies. There are no copyright restrictions; personal or noncommercial use of this database by researchers and teachers is encouraged. Researchers are requested to cite this paper if using all or part of the database. As we intend to keep this database up to date on GitHub (see Metadata S1 for details) and Zenodo (https://doi.org/10.5281/zenodo.3359810), researchers are encouraged to inform us of the applications of this database.

Functional expression of chloride channels and their roles in the cell cycle and cell proliferation in highly differentiated nasopharyngeal carcinoma cells.

We previously demonstrated that the growth of the poorly differentiated nasopharyngeal carcinoma cells (CNE-2Z) was more dependent on the activities of volume-activated chloride channels than that of the normal nasopharyngeal epithelial cells (NP69-SV40T). However, the activities and roles of such volume-activated chloride channels in highly differentiated nasopharyngeal carcinoma cells (CNE-1) are not clarified. In this study, it was found that a volume-activated chloride current and a regulatory volume decrease (RVD) were induced by 47% hypotonic challenges. The current density and the capacity of RVD in the highly differentiated CNE-1 cells were lower than those in the poorly differentiated CNE-2Z cells, and higher than those in the normal cells (NP69-SV40T). The chloride channel blockers, 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) and tamoxifen inhibited the current and RVD. Depletion of intracellular Cl(-) abolished the RVD. The chloride channel blockers reversibly inhibited cell proliferation in a concentration- and time-dependent manner, and arrested cells at the G0/G1 phases, but did not change cell viability. The sensitivity of the three cell lines to the chloride channel blockers was different, with the highest in poorly differentiated cells (CNE-2Z) and the lowest in the normal cells (NP69-SV40T). ClC-3 proteins were expressed in the three cells and distributed inside the cells as well as on the cell membrane. In conclusion, the highly differentiated nasopharyngeal carcinoma CNE-1 cells functionally expressed the volume-activated chloride channels, which may play important roles in controlling cell proliferation through modulating the cell cycle, and may be associated with cell differentiation. Chloride channels may be a potential target of anticancer therapy.