Targeting microbiota-immune-synaptic plasticity to explore the effect of tea polyphenols on improving memory in the aged type 2 diabetic rat model.

OBJECTIVES: The study aimed to explore whether TP could improve memory in the aged type 2 diabetic rat model by regulating microbiota-immune-synaptic plasticity axis. METHODS: The experiment was divided into two parts. Firstly, to investigate the effects of TP on the physiopathology of the aged T2DM model rats, rats were randomly divided into the Normal control group, the aged group, the Aged T2DM model group, the TP 75, 150, 300 mg/kg groups, the 150 mg/kg Piracetam group and the 3 mg/kg Rosiglitazone group. Then, to further verify whether TP improved memory in aged T2DM rat model by regulating intestinal flora, the fecal microbiota transplantation (FMT) from the rats in the 300 mg/kg TP group into the rats in the aged T2DM model group was carried out. Effects on gut microbiota, colonic integrity (epithelial tight junction proteins), and endotoxemia (serum LPS) were examined, along with synaptic structure, synaptic plasticity-related structural proteins and inflammation signaling of the hippocampus in our study. RESULTS: Our results demonstrated that TP alleviated memory impairments in the aged T2DM rat model. The specific outcomes were as follows: TP 300 mg/kg corrected the gut dysbacteriosis, alleviated intestinal permeability reduction and peripheral/central inflammation, inhibited the TLR4/NF-κB signaling pathway. Meanwhile, TP improved the synaptic plasticity in the hippocampus of the aged T2DM model rats, whose expressions of SYN, PSD 95, NMDAR1 and GluR1 in hippocampus were significantly up-regulated. Surprisingly, rats of the FMT group displayed the same changes. DISCUSSION: TP improves the memory in aged T2DM rat model. The mechanism may be related to the alteration of gut flora, which can inhibit hippocampal TLR4/NF-κB signaling to attenuate neuroinflammation, then improve synaptic plasticity. The study proposes that TP interventions aimed at manipulating the gut microbiota may hold great potential as an effective approach for preventing and treating this disease.

[Tea polyphenols improves depression-like behavior in aged type 2diabetes rats by regulating microglia polarization].

OBJECTIVE: To investigate the effect of tea polyphenols(TP) on improving depression-like behavior in aged type 2 diabetes(T2DM) model rats. METHODS: A total of 40 8-week-old SD male rats were randomly divided into the control group(n=10) and the modeling group(n=30) according to the body weight. The rats in the modeling group were fed with high-glucose and high-fat diet and treated with 50 mg/kg D-galactose by intraperitoneal injection daily until the end of the experiment, while the rats in the control group were fed with the standard diet and treated with an equal volume of saline by intraperitoneal injection. After 4 weeks, the rats in the modeling group were injected with 25 mg/kg STZ, meanwhile the rats in the control group were injected with an equal volume of citric acid buffer. The level of fasting blood glucose(FBG) was measured on the 14~(th) day. When FBG≥16.7 mmol/L, the rats were identified as successful model of the T2DM rats. Then, the model rats were randomly divided into the model group, 150, 300 mg/kg TP groups(n=10, respectively), and the rats were given intragastric intervention for 8 weeks. The levels of the FBG were detected, and the depression-like behavior of rats was assessed by the open field test(OFT) and forced swimming test(FST). The density of microglia in hippocampus CA1 region was assessed by immunofluorescence staining, and protein expressions of P53, Iba1, iNOS, Arg-1 and BDNF were determined by western blot. RESULTS: Compared with the control group, the levels of FBG in the rats of the model group were obviously increased(P<0.01). In the OFT, the frequencies of rearing and grooming in the rats of model group markedly was decreased, while in the FST, the immobility time extensively was increased(P<0.01). The density of microglia in hippocampus CA1 region was increased(P<0.01). The expressions of P53, Iba1 and iNOS were increased, and the expressions of Arg-1 and BDNF were decreased(P<0.01). Additionally, compared with the model group, in the OFT, the frequencies of rearing and grooming were increased in the rats in 150 and 300 mg/kg TP group(P<0.01). The density of microglia in hippocampus CA1 region was decreased(P<0.01). The expressions of P53, Iba1 and iNOS were down-regulated, and the expression of BDNF was up-regulated(P<0.01). Additionally, compared with the model group, the levels of FBG was decreased in the rats in the 300 mg/kg TP group(P<0.01). The immobility time was decreased in the FST(P<0.01). The expression of Arg-1 was down-regulated(P<0.01). CONCLUSION: TP can improve depression-like behavior in aged T2DM model rats, and its mechanism may be related to regulate microglia M1/M2 polarization and up-regulate expression of BDNF in hippocampus.

Crosstalk between protein post-translational modifications and phase separation.

The phenomenon of phase separation is quite common in cells, and it is involved in multiple processes of life activities. However, the current research on the correlation between protein modifications and phase separation and the interference with the tendency of phase separation has some limitations. Here we focus on several post-translational modifications of proteins, including protein phosphorylation modification at multiple sites, methylation modification, acetylation modification, ubiquitination modification, SUMOylation modification, etc., which regulate the formation of phase separation and the stability of phase separation structure through multivalent interactions. This regulatory role is closely related to the development of neurodegenerative diseases, tumors, viral infections, and other diseases, and also plays essential functions in environmental stress, DNA damage repair, transcriptional regulation, signal transduction, and cell homeostasis of living organisms, which provides an idea to explore the interaction between novel protein post-translational modifications and phase separation. Video Abstract.

Structure and functional characteristics of starch from different hulled oats cultivated in China.

This work aimed to evaluate the structure and functional characteristics of starch from ten hulled oat cultivars grown in different locations in China. The protein, phosphorus, amylose, and starch contents were 0.2-0.4 %, 475.7-691.8 ppm, 16.2-23.0 %, and 93.6-96.7 %, respectively. All the starches showed irregular polygonal shapes and A-type crystallization with molecular weights ranging from 7.2 × 107 to 4.5 × 108 g/mol. The amounts of amylopectin A (DP 6-12), B1 (DP 13-24), B2 (DP 25-36), and B3 (DP > 36) chains were in the ranges of 10.3-16.0 %, 54.5-64.8 %, 16.5-21.1 %, and 4.9-13.1 %, respectively. The starches differed significantly in gelatinization temperatures, pasting viscosity, solubility, swelling power, rheological properties, and digestion parameters. The results revealed that the larger particle size could increase the peak viscosity of the starch paste. The presence of phosphorus increased the gelatinization temperature and enhanced the resistant starch content. The starch granules with higher crystallinity contained a higher proportion of phosphate, which increased final viscosity and setback viscosity but decreased rapidly digestible starch. Overall, oat starch with a high phosphorus content could be used to prepare low-glycemic-index food for diabetes patients.

Targeting ERS-mitophagy in hippocampal neurons to explore the improvement of memory by tea polyphenols in aged type 2 diabetic rats.

Increasing evidence demonstrated that mitophagy and endoplasmic reticulum stress (ERS) was closely associated with memory decline in elderly type 2 diabetes mellitus (T2DM). Tea polyphenols (TP), an excellent natural antioxidant, has been reported to have neuroprotective properties in aging and diabetes, but the underlying mechanisms are still not fully understood. This study targets ERS-mitophagy in hippocampal neurons to investigate the improvement effect of memory in aged T2DM rats by TP. Rats were randomly divided into the control group, the aged group, the aged T2DM model group, the TP 75, 150, 300 mg/kg groups. TP 300 mg/kg ameliorated mitophagy by decreasing the levels of p-mTOR (S2448), P62 and HSP60 and increasing the levels of PINK1 and Parkin, the ratio of LC3Ⅱ/LC3Ⅰ, co-localization of LC3 and HSP60 and the number of autophagosomes and autolysosomes. TP 300 mg/kg attenuated ERS by downregulating the levels of p-PERK, p-eIF2α, ATF4, GRP78 and restoring the ER structure. To further verify epigallocatechin gallate (EGCG), which is the main active component of TP, enhanced mitophagy by inhibiting ERS, PC12 cells were pretreated with ERS activator tunicamycin (TM) or ERS inhibitor 4-phenylbutyric acid (4-PBA). The results showed that the improvement of mitophagy by EGCG was inhibited by TM and promoted by 4-PBA. Collectively, ERS-mitophagy in hippocampal neurons plays a key role in the improvement of memory by TP in aged T2DM rats. This study will provide a new perspective and strategy for the prevention of memory decline in elderly with T2DM.

Magnetic porous carbon material derived from imine-linked covalent organic frameworks for magnetic solid phase extraction of trace chlorine-containing herbicides in soil.

Here, imine-linked covalent organic frameworks coated Fe3O4 microspheres were fabricated and employed as the self-template to prepare magnetic porous carbon material. The magnetic solid phase extraction (MSPE) performance of such magnetic covalent organic frameworks derived porous carbons (CMCOFs) were studied for the first time, and the improved MSPE performance was verified. The variations of chemical and material properties in the carbonization processes were studied, and it was found that the CMCOFs carbonated at 400°C exhibited highest adsorption efficiencies for chlorine-containing herbicides due to the formation of nitrile components at this stage. The CMCOFs retained high adsorption efficiencies (above 90 %) to chlorine-containing herbicides at wide pH range (3-12) and high salt concentration. The CMCOFs-based MSPE coupled with HPLC technique was in good potential for analysis of trace chlorine-containing herbicides in soil samples. Under the optimized conditions, this approach displayed short extraction and elution time (5 and 8 min) and low limits of detection (0.35-5.5 ng/mL) for chlorine-containing herbicides. The recoveries of spiked analytes and the relative standard deviations in real soil samples were 81.86 %-110.9 % and less than 5.92 %, respectively. This study provides an efficient method for the analysis of trace chlorine-containing herbicides in complex samples, as well as give some inspiration on material modulation by controlled carbonization to achieve improved sorption performances.

Long non-coding RNA EGOT is associated with 131iodine sensitivity and contributes to thyroid cancer progression by targeting miR-641/PTEN axis.

Thyroid cancer is a prevalent endocrine malignancy around the world. Radioactive 131iodine (131I) therapy is widely applied in TC patients, but the resistance affects its effectiveness in the clinics. Long non-coding RNA (lncRNA) EGOT has been reported to induce an inhibitory effect on cancer progression, but the specific function of EGOT in 131I resistance of TC cells remains unclear. Here, we successfully established 131I-resistant TC cells and evaluated the impact of EGOT on 131I resistance in the cells. Our data showed that EGOT and PTEN expression was reduced but the miR-641 expression was enhanced in 131I-resistant TC cells. EGOT inhibited viability, induced apoptosis and enhanced DNA damage in 131I-resistant TC cells. Mechanically, we identified that EGOT induced PTEN expression by targeting miR-641 in 131I-resistant TC cells. Moreover, the depletion of PTEN and miR-641 mimic reversed EGOT-relieved 131I resistance of TC cells in vitro. Thus, we conclude that lncRNA EGOT attenuated 131I resistance of TC cells by targeting miR-641/PTEN axis. The clinical functions of EGOT in TC therapy deserve to be validated in future exploration.

Fabrication of phytoglycogen-derived core-shell nanoparticles: Structure and characterizations.

The objective of this work was to investigate the fabrication of core-shell nanoparticles using phosphorylase-catalyzed chain extension of phytoglycogen, and to analyze the changes of structure and characterizations in detail. During the glucosylation reaction, the inorganic phosphate increased substantially up to 2.3 mg/mL in the initial 12 h, and then increased incrementally to 2.5 mg/mL at 24 h. The similar to trends was observed for increasing Mw and Rz over time, due to glucosyl transfers on the surface chain to form a corona around the phytoglycogen core with a larger size. Phosphorylase modification increases the percentages of longer chain fractions and the average chain length increased from degree of polymerization (DP) 11.6 to DP 48.2. The modified phytoglycogen exhibited the characteristic of B-type crystalline structure, indicating that the specific core-shell nanoparticle with inner amorphous nature and outer crystalline layer. The above results revealed that the potentiality of enzymatic chain elongation of phytoglycogen to design novel core-shell nanoparticle with tailor-made structure and functionality.

Biomimetic synthesis of maltodextrin-derived dendritic nanoparticle and its structural characterizations.

The maltodextrin-derived dendritic nanoparticle was fabricated using microbial branching enzyme and its structural characterizations were investigated. During biomimetic synthesis, molecular weight distribution of maltodextrin substrate with 6.8 × 104 g/mol shifted to the narrower and uniform distribution region with the larger molecular weight up to 6.3 × 106 g/mol (MD12). The enzyme-catalyzed product had the larger size, higher molecular density as well as higher percentage of α-1,6 linkage, accompanying by more chain accumulations of DP 6-12 and disappearance of DP > 24, suggesting the biosynthesized glucan dendrimer had a compact tighter branched structure. The interaction of molecular rotor CCVJ and local structure of dendrimer was monitored, displaying there was a higher intensity related with the numerous nano-pockets at the branch points of MD12. The maltodextrin-derived dendrimers had the single spherical particulate shape with the size range of 10-90 nm. The mathematical models were also established to reveal the chain structuring during enzymatic reaction. The above results showed that the biomimetic strategy for novel dendritic nanoparticle with controllable structure arising from branching enzyme treated maltodextrin, which would help to enlarge the panel of available dendrimer.

Impact of rapid rehabilitation surgery on perioperative nursing in patients undergoing cardiac surgery: A meta-analysis.

OBJECTIVE: To systematically evaluate the effect of enhanced recovery after surgery (ERAS) on perioperative nursing of patients undergoing cardiac surgery. METHODS: A systematic literature search was performed in PubMed, Embase, Web of science, Cochrane, CNKI, Wanfang, and VIP using predefined search strings from inception of database to May 2021. Randomized control trials (RCTs) with sample size >40 on cardiac surgery with either ERAS nursing or routine nursing reporting extubation (trachea) time, length of stay, out of bed activity time, and nursing satisfaction were included in the analysis. Stata SE 12.0 software was used for statistical analysis. RESULTS: A total of 27 RCTs were included. All the included studies were Chinese due to lack of studies in English. The results of meta-analysis showed that the extubation time standardized mean difference ([SMD] = -3.11; 95% confidence interval [CI]: -3.77, -2.45; p < .001), out of bed activity time (SMD = -2.89; 95% CI: -3.34, -2.44; p < .001), and hospitalization time (SMD = -2.08; 95% CI: -2.37, -1.79; p < .001) of cardiac surgery patients with ERAS nursing was significantly shorter than those with routine nursing. The patient's satisfaction after surgery with ERAS was higher than that of routine nursing relative risk ([RR] = 1.24; 95% CI: 1.18, 1.30; p < .001). CONCLUSION: ERAS nursing can accelerate perioperative rehabilitation of patients undergoing cardiac surgery and highly accepted by patients.

Mediation Effects of IL-1ß and IL-18 on the Association Between Vitamin D Levels and Mild Cognitive Impairment Among Chinese Older Adults: A Case-Control Study in Taiyuan, China.

Objective: Mild cognitive impairment (MCI) is a common, chronic, and complex disease in the elderly, which is often influenced by a variety of factors that include nutrition and inflammation. This study was undertaken to evaluate the mediation effects of inflammation on the association between vitamin D levels and MCI. Methods: We explored the associations of inflammation and cognitive impairment related to 25(OH)D3 deficiency among 360 older people from the communities in China. Demographic characteristics, lifestyle, and health status were investigated by questionnaire, cognitive function was detected by MoCA, and plasma 25(OH)D3, interleukin-1ß (IL-1ß), and interleukin-18 (IL-18) were measured by ELISA. Spearman's correlation analysis and logistic regression analysis were used to analyze the relationship among 25(OH)D3, IL-1ß, and IL-18 in the MCI group and the control group and further to analyze the relationship between 25(OH)D3 and inflammatory factors in the MCI group. Finally, mediation analysis was performed to evaluate whether inflammation mediated the effect of 25(OH)D3 deficiency on cognitive impairment. Results: There were lower plasma 25(OH)D3 concentration and higher IL-1ß and IL-18 levels in the MCI group compared with the controls. The levels of 25(OH)D3 were positively correlated with the MoCA scores and scores of different domains; the levels of IL-1ß and IL-18 were negatively correlated with them (p < 0.05). In multivariate logistic analysis, there were significant associations among 25(OH)D3, IL-1ß, IL-18, and MCI after adjusted. Further analysis revealed the significant association between the subjects with VD deficiency and the highest quartile of IL-18 in MCI (OR = 4.066), not with IL-1ß after adjusting the confounding variables in MCI group. Ultimately, mediation analysis suggested that IL-1ß and IL-18 could explain 25.4 and 17.5% of effect of the risk of cognitive impairment related to 25(OH)D3 deficiency. Conclusion: Our findings suggested that 25(OH)D3 deficiency could increase the risk of cognitive impairment by a mechanism partly involving inflammation. Therefore, vitamin D supplementation may improve or delay the decline in cognitive function caused by inflammation in the elderly.

Robust Beamforming Based on Graph Attention Networks for IRS-Assisted Satellite IoT Communications.

Satellite communication is expected to play a vital role in realizing Internet of Remote Things (IoRT) applications. This article considers an intelligent reflecting surface (IRS)-assisted downlink low Earth orbit (LEO) satellite communication network, where IRS provides additional reflective links to enhance the intended signal power. We aim to maximize the sum-rate of all the terrestrial users by jointly optimizing the satellite's precoding matrix and IRS's phase shifts. However, it is difficult to directly acquire the instantaneous channel state information (CSI) and optimal phase shifts of IRS due to the high mobility of LEO and the passive nature of reflective elements. Moreover, most conventional solution algorithms suffer from high computational complexity and are not applicable to these dynamic scenarios. A robust beamforming design based on graph attention networks (RBF-GAT) is proposed to establish a direct mapping from the received pilots and dynamic network topology to the satellite and IRS's beamforming, which is trained offline using the unsupervised learning approach. The simulation results corroborate that the proposed RBF-GAT approach can achieve more than 95% of the performance provided by the upper bound with low complexity.

Exploration of severe Covid-19 associated risk factor in China: Meta-analysis of current evidence.

AIM: This meta-analysis aimed to explore potential risk factors for severe Covid-19. METHODS: We systemically and comprehensively retrieved the eligible study evaluating clinical differences between severe vs non-severe Covid-19. Main effect sizes were demographic characteristics, comorbidities, signs and symptoms, laboratory findings as well as radiological features of chest CT. RESULTS: A total of 2566 Covid-19 people (771 in the severe group and 1795 in the non-severe group) from 14 studies were eligible for this meta-analysis. It was demonstrated that older age and males were more likely to have severe Covid-19. Patients with underlying comorbidities, such as hypertension, diabetes, heart disease and COPD were significantly more susceptible to severe Covid-19. Patients with dyspnoea were more likely to be severely ill. Depressed total lymphocytes were observed in this article. Meanwhile, although reticulation (30.8%), intrathoracic lymph node enlargement (20.5%) and pleural effusions (30.8%) were relatively infrequent, meta-analysis revealed that patients with these presentations in chest CT were associated with increased risk of severe Covid-19. CONCLUSIONS: There are significant differences in clinical characteristics between the severe and non-severe Covid-19 patients. Many factors are related to the severity of the disease, which can help clinicians to differentiate severe patients from non-severe patients.

Design of Rapid Detection System for Five Major Carbapenemase Families (bla KPC, bla NDM, bla VIM, bla IMP and bla OXA-48-Like) by Colorimetric Loop-Mediated Isothermal Amplification.

PURPOSE: Carbapenemase-producing Enterobacteriaceae (CPE) infection constitutes a public health threat. Timely and efficient diagnosis is of paramount importance for prompt and effective therapy. In order to quickly and comprehensively detect the five major families of carbapenemases (bla KPC, bla NDM, bla VIM, bla IMP, and bla OXA-48-like), colorimetric loop-mediated isothermal amplification (LAMP) was employed. MATERIALS AND METHODS: Five sets of LAMP primers were designed, each of which can, respectively, amplify all the carbapenemase subtypes described in this work. Twenty whole genome sequencing-verified-"standard strains", including 1 bla NDM-1, 1 bla NDM-5, 1 bla NDM-6, 1 bla NDM-7, 2 bla IMP-4, 1 bla IMP-8, 2 bla KPC-2, 1 bla KPC-3, 1 bla KPC-4, 1 bla KPC-5, 1 bla KPC-6, 1 bla KPC-7, 1 bla OXA-48 and 1 bla OXA-181 carrier, and 1 bla VIM and bla OXA-244, 1 bla KPC-2 and bla IMP-4, 1 bla KPC-2 and bla VIM-1 and 1 bla KPC-2 and bla NDM-1-co-carriers, were used to establish a 25-microliter visual LAMP reaction system (kept at 65°C for 30 minutes in water bath). Color change from bright pink to yellow indicated positive amplification. In addition, 126 pre-verified clinical carbapenem-resistant Enterobacteriaceae (CRE) isolates, including 65 CPE (23 bla NDM, 2 bla OXA-48-like, 1 bla KPC and bla VIM, 2 bla IMP, and 37 bla KPC carriers) and 61 non-CPE, were also detected. RESULTS: With the lowest detection limit of 10 colony forming units (CFU) per reaction for LAMP and 103 CFU per reaction for PCR, the LAMP system demonstrated dramatically higher sensitivity while retaining the same specificity. Furthermore, we demonstrated concordant results between the two methods for the 126 clinical isolates. CONCLUSION: Therefore, LAMP could be used for rapid identification of the five major carbapenemase gene families in routine clinical laboratories.

Temporal responses of hydrochemical variables and dissolved Fe(II) to flooding at a lake riparian wetland under different vegetation revealing by high resolution DGT.

The interplay between hydrological and biogeochemical processes in riparian wetland was recognized to lead directly to the temporal variations of surface water quality. However, the effects of flooding and vegetation on the release and entrapment of heavy metals and nutrients in riparian wetland remain poorly understood. The study aimed at investigating the influences of flooding and vegetation on the hydrochemical and Fe-redox change in the soil porewater and shallow groundwater, in Poyang lake riparian wetland through hydrochemical monitoring and diffusive gradient technology (DGT). The hydrochemical profiles and results of PCA analysis on the temporal datasets both demonstrated that vegetation had significant influences on the hydrochemistry of rhizosphere depth zone (RDZ) and shallow groundwater depth zone (SGZ). The Ca, K, Na, Mg, Mn and DOC at RDZ of both plants showed significant increasing trends from pre-to post-flooding while were observed minor change at the SGZ. The extracted PC1-PC3 from PCA analysis suggested that mineral dissolution and fermentation were dominating processes that explained 64.1% of the hydrochemical variability under the wetting-drying cycle. The synchronous changes of Fe(II), SO42-, DOC and ORP were found to occur at the SGZ of Carex, implying the likely occurrence of Fe- and S- redox reactions. The Fe(II) DGT profiles evidenced the temporal iron reduction and oxidation occurring at the rhizosphere following the wetting-drying cycle, as also reflected by the high opposite Fe2+ and DO association through PCA analysis. The high resolution temporal-spatial Fe(II) distribution suggested also the interface between lake water and groundwater was relatively stable under flooding. These results highlight that the release of dissolved Fe(II) from the wetland rhizosphere driven by flood may result in the release of Fe-associated heavy metals from riparian wetland to surface water, and hence pose potential threats to the surface water quality. Thereby, the flow and flood should be properly controlled and vegetation effects need to be carefully considered in the water resources management of lake-floodplain system.

Effect of Oral versus Vaginal Administration of Estradiol and Dydrogesterone on the Proliferative and Secretory Transformation of Endometrium in Patients with Premature Ovarian Failure and Preparing for Assisted Reproductive Technology.

PURPOSE: This study aimed to assess the efficacy of vaginally versus orally administered estradiol (E2) and dydrogesterone (DG) on the proliferative and secretory transformation of endometrium in patients with premature ovarian failure (POF) and preparing for assisted reproductive technology. METHODS: Twenty patients with POF who were awaiting oocyte donation were included in the study; they were randomly assigned to two groups to receive E2 and DG either orally or vaginally. Treatment efficacy was compared between the two groups regarding blood E2 concentrations, endometrial thickness, histology using hematoxylin and eosin staining, immunohistochemical analysis of ER expression, and PR and pinopodes morphology using scanning electron microscopy. RESULTS: E2 concentrations differed significantly between oral and vaginal E2 and DG administration for 14 days (82.3 vs 1015.6 pg/mL; P < 0.001) and 21 days (85.0 vs 809.8 pg/mL; P < 0.001). Endometrial thickening was more pronounced in the vaginal treatment group, and also ER staining was stronger on days 14 and 21 in the vaginal treatment group. PR staining in the endometrium appeared more intense in the oral treatment group, which was, however, not significant. The abundance of developing pinopodes was higher in the vaginal treatment group (P = 0.04). CONCLUSION: Vaginal administration of E2 and DG is more effective than oral administration regarding proliferative and secretory transformation of the endometrium in POF patients and preparing for assisted reproductive technology.

Shift in plant-soil interactions along a lakeshore hydrological gradient.

Wetlands occupy the transitional zone between aquatic and terrestrial systems. Hydrological conditions have significant influence on wetland plant communities and soil biogeochemistry. However, our knowledge about plant-soil interactions in wetlands along hydrological gradients is still limited, although it is crucial to guide wetland management decisions and to adapt, whenever possible, hydrological conditions to the different plant communities. To this aim, we related vegetation composition, plant functional traits, soil physicochemical properties, soil microbial biomass, and soil enzymatic activities in wetlands on the southeastern shore of Neuchâtel lake, Switzerland, a lake whose level is partly regulated. Aboveground and belowground plant biomass and correspondent C, N and P concentrations remained constant or decreased moving from the vegetation community subjected to more frequent flooding events to the community with almost no flooding. The soil organic layer exhibited always higher nutrient concentrations and greater enzymatic activities than the organo-mineral and mineral layers. The chemical and biological characteristics of the soil organic layer showed decreasing values for most of the parameters along the hydrological gradient from lakeshore to upland wetland communities. On the basis of nutrient stoichiometry, plant-soil system in the plant community with most flooding events had no-nutrient limitation, while there was a N limitation in the transitional community. In the upland plant community where there was no flooding effect, the plant-soil system was characterized by N and P co-limitation. These findings are important because they provide a threshold for flooding regime by the lake in the context of optimization of lake level regulation under various stakeholders needs.

Seasonal variability of groundwater level effects on the growth of Carex cinerascens in lake wetlands.

Groundwater level is crucial for wetland plant growth and reproduction, but the extent of its effect on plant growth can vary along with changed precipitation and temperature at different seasons. In this context, we investigated the effect of two groundwater levels (10 cm vs. 20 cm depth) on growth and reproductive parameters of Carex cinerascens, a dominant plant species in the Poyang Lake wetland, during three seasons (spring, summer, and autumn) and during two consecutive years (2015 and 2016). Carex cinerascens showed low stem number, height, and individual and population biomass in summer compared to spring and autumn. 10 cm groundwater level was overall more suitable for plant growth resulting in higher stem height and biomass. However, the interactive effect between groundwater level and season clearly demonstrated that the effect of groundwater level on plant growth occurred mainly in autumn. After the withering of the plant population in summer, we observed that C. cinerascens growth recovered in autumn to similar values observed in spring only with 10 cm groundwater level. Consequently, we could deduce that lowering groundwater level in the studied Poyang Lake wetland will negatively impact C. cinerascens regeneration and growth particularly during the second growth cycle occurring in autumn. Additionally, our results showed that, independently of the season and groundwater level, population biomass of C. cinerascens was lower during drier year. Altogether, our findings suggest that water limitation due to both reduction in precipitation and decreased groundwater level during the year can strongly impact plant communities.

Accuracy and applicability of different phenotypic methods for carbapenemase detection in Enterobacteriaceae: A systematic review and meta-analysis.

OBJECTIVES: Carbapenem-resistant Enterobacteriaceae (CRE) are a major public-health threat. The most important mechanism of carbapenem resistance in CRE is carbapenemase production. Early identification of carbapenemase-producing Enterobacteriaceae (CPE) leads to improved clinical outcomes. This systematic review aimed to assess the accuracy and applicability of the modified Hodge test (MHT), the carbapenemase Nordmann-Poirel (Carba NP) test, the modified carbapenem inactivation method (mCIM) and matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF/MS) for CPE detection. METHODS: The meta-analysis included pooled sensitivity, specificity, diagnostic odds ratio, and summary receiver operating characteristic (SROC) curve and area under the curve (AUC). RESULTS: A total of 67 studies were included in the analysis. Pooled effect sizes (95% confidence interval) of the MHT, Carba NP, mCIM and MALDI-TOF/MS, respectively, were as follows: sensitivity, 92% (87-95%), 97% (94-98%), 99% (99-100%) and 99% (96-100%); specificity, 93% (86-97%), 100% (99-100%), 99% (96-100%) and 99% (96-100%); diagnostic odds ratio, 98.156 (48.175-199.995), 1277.710 (751.391-2172.692), 3597.352 (1287.575-10000) and 1781.360 (651.827-4868.228); and AUC, 0.97, 1, 1 and 1. CONCLUSION: Carba NP, mCIM and MALDI-TOF/MS all demonstrated high accuracy in CPE detection, whereas the MHT is not recommended owing to some clear drawbacks. We recommend the selection of carbapenemase detection tests in the order of mCIM, Carba NP and MALDI-TOF/MS according to their simplicity, cost, and equipment and skills involved.