Evaluation of total phenolic, flavonoid, carbohydrate contents and antioxidant activities of various solvent extracts from Angelica amurensis root

We investigated the antioxidant activities of different solvent extracts of Angelica amurensis root (AAR). The yield of aqueous extract was the highest. The methanol extract had the highest total phenolic content and total flavonoid content. The aqueous extract showed the highest total carbohydrate content. Methanol and ethanol extracts showed high DPPH and ABTS radical-scavenging abilities, and high antioxidant activities in FRAP and CUPRAC assays. The extract of chloroform and water exhibited high ability to scavenge hydroxyl radicals. All extracts showed high inhibition of β-carotene bleaching, ethyl acetate extract showed the best effect. Ethyl acetate extract exhibited the highest protection against cellular oxidative damage. The best extraction solvent for the active substance in AAR was methanol. AAR may act as a natural antioxidant.

Synthesis, α-Glucosidase inhibition and molecular docking studies of tyrosol derivatives

To find a potent α-glucosidase inhibitor, 24 tyrosol derivatives with different substituents located at the meta, ortho, or para position of the phenyl group have been synthesised via the Mitsunobu reaction, characterised by ¹H NMR, ¹³C NMR, ESI-MS and IR and evaluated for inhibition. The derivatives possessed varying degrees of in vitro inhibitory activity against α-glucosidase and a relationship between the structure and activity was subsequently established for all compounds. Two of these compounds with substituents at the para position showed significant inhibitory effects surpassing that of the control standard acarbose. Molecular docking studies performed to better understand the binding interactions between the enzyme and the two most active compounds showed substantial binding within the active site of α-glucosidase. Taken together, these results indicate that the position of the substituent plays a crucial role in this inhibition and may facilitate the development of new α-glucosidase inhibitors.

Chemical composition and biological activities of an essential oil from the aerial parts of Artemisia Gmelinii weber ex Stechm

The aerial parts of Artemisia gmelinii Weber ex Stechm were collected from the northeast of China. The essential oil was obtained by hydrodistillation and analysed by GC-MS. A set of 66 compounds were identified representing 99.1% of the oil composition. The major compounds in the oil were cyclobutaneethanol, endo-borneol, germacrene D, eucalyptol, selin-6-en-4α-ol, bisabolone oxide A, caryophyllene and terpinen-4-ol. Moreover, the essential oil was evaluated for its antioxidant, antidiabetic, and anticholinesterase activities in vitro. Additionally, the antioxidant potential of the oil was evaluated using DPPH and ABTS assays. The oil showed good antidiabetic activity with an IC₅₀ of 63.2 µg/mL, which was similar to that of the positive control acarbose, and weak anticholinesterase activities. These findings demonstrated that the essential oil of Artemisia gmelinii may be a good natural antidiabetic.

[Expression and significance of STOX1 in villi and placenta at different stages of normal gestation]

Objective: To investigate the expression and significance of STOX1 in different stages of gestation villi and placenta. Methods: Totally 137 cases of normal villi and placenta of pregnant women were collected from the Department of Obstetrics of Shanghai Pudong Hospital from October 1(st) 2015 to February 28(th) 2018, including 64 cases of early pregnancy (early pregnancy group) which consists of 32 cases of 5-7(+6) weeks gestation (early pregnancy group A) and 32 cases of 8-11(+3) weeks gestation (early pregnancy group B), 28 cases of 14-26 weeks gestation(middle pregnancy group) and 45 cases of 37-41 weeks gestation (late pregnancy group). The expression and localization of STOX1 mRNA and protein in placenta were evaluated by RT-qPCR, Western blotting and immunohistochemistry. Results: (1)STOX1 was positively expressed in the cytotrophoblasts and syncytiotrophoblasts as well as interstitial and vascular endothelial cells of all groups. (2)STOX1 mRNA expression in each group was significantly different (P<0.05), the lowest was in the early pregnancy group A(0.007 8±0.000 4), which increased along with the progression of gestational age(P<0.05),and reached the highest level in the third trimester(0.064 4±0.001 3). (3)The protein level of STOX1 in different stages of normal pregnancy was 0.53±0.20 in early pregnancy group A;0.62±0.37 in early pregnancy group B;0.70±0.03 in middle pregnancy group and 0.81±0.04 in late pregnancy group respectively; which was positively related with the progression of gestational age (P<0.05). Conclusion: The expressions of STOX1 is gradually increasing along with the normal pregnancy progression, suggesting that it might be involved in proliferation, differentiation and infiltration and (or) apoptosis of trophoblast cells and the development of the placenta.

An acute gastroenteritis outbreak associated with person-to-person transmission in a primary school in Shanghai: first report of a GI.5 norovirus outbreak in China

Background

GII noroviruses are a common cause of acute gastroenteritis (AGE) outbreaks in institutional settings globally. However, AGE outbreaks caused by GI norovirus, especially the GI.5 genotype, are relatively uncommon.

Methods

In February 2017, an AGE outbreak occurred in a primary school in Shanghai, China. An outbreak investigation was undertaken, and fecal specimens, rectal swabs, and environmental swabs were collected. Pathogen detection was performed and the positive specimens were characterized by gene sequencing.

Results

The descriptive epidemiological analysis suggested that this outbreak, involving 19 cases in two classes (designated classes A and B), was a small-scale propagated epidemic and person-to-person transmission was the most plausible transmission mode. The outbreak comprised two peaks, with 15 cases occurring in class A during the main peak and four cases occurring in class B in the subsequent minor peak. The primary attack rate was 38% and the secondary attack rate was 10%. Univariable logistic regression indicated that contacting a suspect case was a risk factor for norovirus infection, with an unadjusted OR of 5.6 (95% CI: 1.6–20.1). Six fecal specimens were positive for GI norovirus, with a single genotype, GI.5 norovirus, being involved, as characterized by genotyping. This outbreak was the first reported outbreak of GI.5 norovirus in China.

Conclusions

This study implies that GI.5 norovirus is a potential agent of outbreaks spread by person-to-person transmission in institutional settings. The investigation highlights the importance of sensitive surveillance, timely isolation of individuals who are ill, adequate hand hygiene, and proper environmental disinfection for prevention and control of AGE outbreaks caused by norovirus.

Impact of understory vegetation on soil carbon and nitrogen dynamic in aerially seeded Pinus massoniana plantations

Understory vegetation plays a vital role in regulating soil carbon (C) and nitrogen (N) characteristics due to differences in plant functional traits. Different understory vegetation types have been reported following aerial seeding. While aerial seeding is common in areas with serious soil erosion, few studies have been conducted to investigate changes in soil C and N cycling as affected by understory vegetation in aerially seeded plantations. Here, we studied soil C and N characteristics under two naturally formed understory vegetation types (Dicranopteris and graminoid) in aerially seeded Pinus massoniana Lamb plantations. Across the two studied understory vegetation types, soil organic C was significantly correlated with all measured soil N variables, including total N, available N, microbial biomass N and water-soluble organic N, while microbial biomass C was correlated with all measured variables except soil organic C. Dicranopteris and graminoid differed in their effects on soil C and N process. Except water-soluble organic C, all the other C and N variables were higher in soils with graminoids. The higher levels of soil organic C, microbial biomass C, total N, available N, microbial biomass N and water-soluble organic N were consistent with the higher litter and root quality (C/N) of graminoid vegetation compared to Dicranopteris. Changes in soil C and N cycles might be impacted by understory vegetation types via differences in litter or root quality.

[Carbon density distribution characteristics and influencing factors in aerially seeded Pinus massoniana plantations]

The distribution characteristics of carbon density under aerially seeded Pinus massoniana plantations in Ganzhou City of Jiangxi Province were studied. Total 15 factors, including site, stand, understory vegetation, litter and so on were selected to establish a relationship model between stand carbon density and influencing factors, and the main influencing factors were also screened. The results showed that the average carbon density was 98.29 t·hm^-2 at stand level with soil layer (49.58 t·hm^-2) > tree layer (45.25 t·hm^-2) > understory vegetation layer (2.23 t·hm^-2) > litter layer (1.23 t·hm^-2). Significantly positive correlations were found among the tree, litter and soil layers, but not among the other layers. The main factors were tree density, avera-ge diameter at breast height (DBH), soil thickness, slope position, stand age and canopy density to affect carbon density in aerially seeded P. massoniana plantations. The partial correlation coefficients of the six main factors ranged from 0.331 to 0.434 with significance by t test. The multiple correlation coefficient of quantitative model I reached 0.796 with significance by F test (F=9.28). For stand density, the best tree density and canopy density were 1500-2100 plants·hm^-2 and 0.4-0.7, respectively. The moderate density was helpful to improve ecosystem carbon sequestration. The carbon density increased with increasing stand age, DBH and soil thickness, and was higher in lower than middle and upper slope positions.

Multilevel Nonlinear Mixed-Effect Crown Ratio Models for Individual Trees of Mongolian Oak (Quercus mongolica) in Northeast China

In this study, an individual tree crown ratio (CR) model was developed with a data set from a total of 3134 Mongolian oak (Quercus mongolica) trees within 112 sample plots allocated in Wangqing Forest Bureau of northeast China. Because of high correlation among the observations taken from the same sampling plots, the random effects at levels of both blocks defined as stands that have different site conditions and plots were taken into account to develop a nested two-level nonlinear mixed-effect model. Various stand and tree characteristics were assessed to explore their contributions to improvement of model prediction. Diameter at breast height, plot dominant tree height and plot dominant tree diameter were found to be significant predictors. Exponential model with plot dominant tree height as a predictor had a stronger ability to account for the heteroskedasticity. When random effects were modeled at block level alone, the correlations among the residuals remained significant. These correlations were successfully reduced when random effects were modeled at both block and plot levels. The random effects from the interaction of blocks and sample plots on tree CR were substantially large. The model that took into account both the block effect and the interaction of blocks and sample plots had higher prediction accuracy than the one with the block effect and population average considered alone. Introducing stand density into the model through dummy variables could further improve its prediction. This implied that the developed method for developing tree CR models of Mongolian oak is promising and can be applied to similar studies for other tree species.

Tim-3 expression on peripheral monocytes and CD3+CD16/CD56+natural killer-like T cells in patients with chronic hepatitis B

Hepatitis B virus (HBV) infection is one of the major causes of chronic liver inflammation. Tim-3 acts as a negative regulatory molecule and plays a critical role in immune tolerance. In the current study, we investigated Tim-3 expression on peripheral monocytes and CD3+CD16/CD56+ natural killer like T (NKT-like) cells in chronic hepatitis B (CHB) patients. Peripheral blood mononuclear cells (PBMCs) were isolated from 52 CHB patients and 60 healthy controls. Tim-3+CD14+ cells and Tim-3+CD3+CD16/CD56+ cells were analyzed by flow cytometry. Results showed that expression of Tim-3 was significantly increased on both the monocytes and NKT-like cells in CHB patients than in controls (P = 0.002 and P < 0.001, respectively). Tim-3 levels on monocytes and NKT-like cells were further upregulated in patients with acute-on-chronic liver failure (ACLF). In addition, we assessed the correlation of Tim-3 expression with levels of alanine aminotransferase (ALT) and tumor necrosis factor alpha (TNF-α). Data revealed that Tim-3 expression on both monocytes and NKT-like cells was positively correlated with level of ALT (r = 0.59, P < 0.001, and r = 0.60, P < 0.001, respectively), whereas Tim-3 expression on NKT-like cells was negatively correlated with serum level of TNF-α (r = -0.54, P < 0.001) in CHB patients. Our results suggest that Tim-3 may play important roles in the pathogenesis of CHB.

Comparative proteomic analysis of rice seedlings in response to inoculation with Bacillus cereus

Reports suggest that Bacillus spp. can be used to increase plant growth and resistance to disease, but the molecular mechanisms underlying the interaction between Bacillus spp. and plant is not completely understood. In the present study, to clarify these underlying mechanisms, the interaction between Bacillus cereus and rice was investigated using two-dimensional gel electrophoresis. Through comparative analysis, a total of 31 differentially expressed proteins were obtained upon B. cereus NMSL88 treatment, including 22 proteins that were up-regulated and nine that were down-regulated. These data indicated that certain proteins involved in plant growth and development were up-regulated, such as xyloglucan endotransglycosylase. Interestingly, proteins involved in defence were also up-regulated, including peroxidases, glutathione S-transferases and kinases. Thus, proteins associated with disease resistance characteristics were induced in the plants after exposure to B. cereus NMSL88. In addition, several proteins involved in protein and lipid metabolism showed significant changes in expression.

SIGNIFICANCE AND IMPACT OF THE STUDY

The present study is the first report to reveal the molecular mechanisms involved in rice seedlings in response to inoculation with Bacillus cereus at the level of proteome. The results demonstrated that B. cereus NMSL88 can up-regulate the expression of proteins related to plant growth and defence, and lead to enhanced plant growth and disease resistance.

Reaction pathways of Sc+ (3D, 1D) and Fe+ (6D, 4F) with acetone in the gas phase: metal ion oxidation and acetone deethanization

The reactions of Sc(+) ((3)D, (1)D) and Fe(+) ((6)D, (4)F) with acetone have been investigated in both high- and low-spin states using density functional theory. Our calculations have indicated that oxidation of Sc(+) by acetone can take place by (1) metal-mediated H migration, (2) direct methyl-H shift and/or (3) C=O insertion. The most energetically favorable pathway is metal-mediated H migration followed by intramolecular ScO(+) rotation and dissociation. For the deethanization of acetone mediated by Fe(+), the reaction occurs on either the quartet or sextet surfaces through five elementary steps, i.e. encounter complexation, C-C bond activation, methyl migration, C-C coupling and non-reactive dissociation. The rate-determining step along the quartet-state potential-energy surface (PES) is similar to that in the case of Ni(+) ((2)F, 3d(9)), namely the methyl-migration step. For the sextet-state PES, however, the energy barrier for methyl migration is lower than that for C-C bond activation, and the rate-determining step is C-C coupling. In general, the low-spin-state pathways are lower in energy than the high-spin-state pathways; therefore, the reaction pathways for the oxidation of Sc(+) and the Fe(+)-mediated deethanization of acetone mostly involve the low-spin states.