Suppression of nighttime sap flux with lower stem photosynthesis in Eucalyptus trees.

It is widely accepted that substantial nighttime sap flux (J s,n) or transpiration (E) occurs in most plants, but the physiological implications are poorly known. It has been hypothesized that J s,n or E serves to enhance nitrogen uptake or deliver oxygen; however, no clear evidence is currently available. In this study, sap flux (J s) in Eucalyptus grandis × urophylla with apparent stem photosynthesis was measured, including control trees which were covered by aluminum foil (approximately 1/3 of tree height) to block stem photosynthesis. We hypothesized that the nighttime water flux would be suppressed in trees with lower stem photosynthesis. The results showed that the green tissue degraded after 3 months, demonstrating a decrease in stem photosynthesis. The daytime J s decreased by 21.47%, while J s,n decreased by 12.03% in covered trees as compared to that of control, and the difference was statistically significant (P < 0.01). The linear quantile regression model showed that J s,n decreased for a given daytime transpiration water loss, indicating that J s,n was suppressed by lower stem photosynthesis in covered trees. Predawn (ψ pd) of covered trees was marginally higher than that of control while lower at predawn stomatal conductance (g s), indicating a suppressed water flux in covered trees. There was no difference in leaf carbon content and δ(13)C between the two groups, while leaf nitrogen content and δ(15)N were significantly higher in covered trees than that of the control (P < 0.05), indicating that J s,n was not used for nitrogen uptake. These results suggest that J s,n may act as an oxygen pathway since green tissue has a higher respiration or oxygen demand than non-green tissue. Thus, this study demonstrated the physiological implications of J s,n and the possible benefits of nighttime water use or E by the tree.

Echinacea purpurea (L.) Moench extract suppresses inflammation by inhibition of C3a/C3aR signaling pathway in TNBS-induced ulcerative colitis rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Echinacea purpurea (L.) Moench (EP) is a perennial herbaceous flowering plant, commonly known as purple conical flower. It was widely used to treat skin inflammation and gastrointestinal diseases. AIM OF STUDY: Ulcerative colitis (UC) is a chronic and nonspecific inflammatory disease. Recent evidence shows that immune disorders are involved in the pathogenesis of UC. To evaluate the protective effect of Echinacea purpurea (L.) Moench exact (EE) on UC and explore the role of complement system in the treatment of UC. MATERIALS AND METHODS: UC model was induced in rats by 2,4,6-trinitrobenzene sulfonic acid (TNBS), and then rats were administered with EE for 10 days. Collect colon tissues for analysis of relevant mechanisms. RESULTS: EE could reduce the weight loss and diarrhea of UC rats. In addition, EE could improve the integrity of intestinal epithelial barrier in UC rats. EE inhibited the level of proinflammatory cytokines and promoted the antioxidation. Furthermore, EE suppressed the expression of C3aR, CFB, CD55, TLR4 and NLRP3. CONCLUSION: These results indicate that EE may achieve therapeutic effect by inhibiting C3a/C3aR signal pathway, suggesting that EE may be used as a medicinal plant to alleviate UC.

Effects of ShenLing BaiZhu San Supplementation on Gut Microbiota and Oxidative Stress in Rats with Ulcerative Colitis.

The aim of this study was to evaluate the effect of gut microbiota and antioxidation of Shenling Baizhu San (SLBZS) as a supplement in a rat model of ulcerative colitis (UC) induced by 2,4,6-trinitrobenzenesulfonic acid (TNBS). Acute intestinal inflammation was induced in 40 male SD rats aged 4 weeks with 100 mg/kg TNBS, and then three dosages of SLBZS (0.5 g/kg, 1 g/kg, and 1.5 g/kg) were administered for eight days, respectively. Faecal microbiome composition was assessed by 16S rRNA high-throughput sequencing. The result indicated that SLBZS could reduce the diversity of gut microbiota and increased its abundance. At the genus level, the relative abundance of SCFAs producing bacteria including Prevotella and Oscillospira increased, while the relative abundance of opportunistic pathogens including Desulfovibrio and Bilophila decreased. Meanwhile, SLBZS could improve the lesions of colon and significantly reduce the level of MPO, increase the levels of SOD and CAT in rats' serum. These findings revealed that SLBZS was effective and possessed anticolitic activities in a rat model of UC by reducing macroscopical and microscopical colon injury, enhancing antioxidant capacity, and regulating gut microbiota.

Antioxidant activities of sulfated Codonopsis polysaccharides in acute oxidative stress.

This study aimed to explore the protective effect of sulfated Codonopsis polysaccharides (SCP) on acute oxidative stress. SCP was modified by chlorosulfonic acid-pyridine method from Codonopsis polysaccharides (CP), which had 34.48% of sulfate content determined by ultrasonic-acidic barium chromate spectrophotometry. The analysis of Fourier transform-infrared spectroscopy (FT-IR) appeared an absorption peak of SCP at 811.91 cm-1 , which related to C-O-SO3 . In vitro test, the antioxidant activities of CP and SCP was induced by H2 O2 in RAW264.7 cells, results indicated that SCP and CP could significantly enhance the activity of superoxide dismutase (SOD), glutathione peroxidase (GDH-Px) and catalase (CAT), and nitric oxide (NO) and decrease the level of malondialdehyde (MDA), reactive oxygen species (ROS), and inducible nitric oxide synthase (iNOS) secreted by RAW264.7 cells compared with modeling group (p < .05). The flow cytometry results also revealed that SCP and CP could markedly inhibit the apoptosis of macrophage induced by acute oxidative stress. In vivo test, 50% ethanol was used to induce mice acute oxidative stress, results indicated that the blood biochemical parameters in mice were restored to normal levels following administration of SCP and CP, and alanine aminotransferase (ALT), aspartate transaminase (AST), total protein (TP), albumin (ALB), glucose (GLU), and creatinine (UREA) had significant differences compared with modeling group (p < .05). Quantitative real-time PCR analysis revealed that SCP and CP could promote the expression of Keap1 and Nrf2. In summary, both SCP and CP had protective effects against acute oxidative stress. PRACTICAL APPLICATIONS: Oxidative stress is a kind of stress injury, which can cause a variety of diseases and accelerate physical aging. Codonopsis has many active components, among which Codonopsis polysaccharide has antioxidant effect. Recent studies have found that Codonopsis polysaccharides could be modified by sulfate molecules to obtain higher antioxidant activity. The modified Codonopsis polysaccharides could significantly promote the production of antioxidant enzymes (SOD, CAT, GDH-Px) and reduce the content of oxidative stress marks (ROS, MDA). Moreover, its antioxidant mechanism may be related to the Keap1 /Nrf2 signaling pathway. Therefore, SCP was an effective antioxidant, and could be used as a potential health food with antioxidant and anti-aging effects.

Higher assimilation than respiration sensitivity to drought for a desert ecosystem in Central Asia.

Responses of ecosystem assimilation and respiration to global climate change vary considerably among terrestrial ecosystems constrained by both biotic and abiotic factors. In this study, net CO2 exchange between ecosystem and atmosphere (NEE) was measured over a 4-year period (2013-2016) using eddy covariance technology in a desert ecosystem in Central Asia. Ecosystem assimilation (gross primary production, GPP) and respiration (Reco) were derived from NEE by fitting light response curves to NEE data based on day- and nighttime data, and their responses to soil water content (SWC) and evaporative fraction (EF) were assessed during the growing season. Results indicated that both GPP and Reco linearly decreased with declining SWC, with the sensitivity of GPP to SWC being 3.8 times higher than that of Reco during the entire growing season. As a result, ecosystem CO2 sequestration capacity decreased from 4.00µmolm-2s-1 to 1.00µmolm-2s-1, with increasing soil drought. On a seasonal scale, significant correlation between GPP and SWC was only found in spring while that between Reco and SWC was found in all growing seasons with the sensitivity increasing steadily from spring to autumn. EF had a low correlation with SWC, GPP and Reco (R2=0.03, 0.02, 0.05, respectively), indicating that EF was not a good proxy for soil drought and energy partitioning was not tightly coupled to ecosystem carbon exchanges in this desert ecosystem. The study deepens our knowledge of ecosystem carbon exchange and its response to drought as well as its coupling with ecosystem energy partitioning in an extreme dry desert. The information is critical for better assessing carbon sequestration capacity in dryland, and for understanding its feedback to climate change.