Development and validation of the screening tool for age-related hearing loss in the community based on the information platform.

INTRODUCTION: Currently, age-related hearing loss has become prevalent, awareness and screening rates remain dismally low. Duing to several barriers, as time, personnel training and equipment costs, available hearing screening tools do not adequately meet the need for large-scale hearing detection in community-dwelling older adults. Therefore, an accurate, convenient, and inexpensive hearing screening tool is needed to detect hearing loss, intervene early and reduce the negative consequences and burden of untreated hearing loss on individuals, families and society. OBJECTIVES: The study harnessed "medical big data" and "intelligent medical management" to develop a multi-dimensional screening tool of age-related hearing loss based on WeChat platform. METHODS: The assessment of risk factors was carried out by cross-sectional survey, logistic regression model and receiver operating characteristic (ROC) curve analysis. Combining risk factor assessment, Hearing handicap inventory for the elderly screening version and analog audiometry, the screening software was been developed by JavaScript language and been evaluated and verified. RESULTS: A total of 401 older adults were included in the cross-sectional study. Logistic regression model (univariate, multivariate) and reference to literature mention rate of risk factors, 18 variables (male, overweight/obesity, living alone, widowed/divorced, history of noise, family history of deafness, non-light diet, no exercising habit, smoking, drinking, headset wearer habit, hypertension, diabetes, hyperlipidemia, cardiovascular and cerebrovascular diseases, hyperuricemia, hypothyroidism, history of ototoxic drug use) were defined as risk factors. The area under the ROC curve (AUC) of the cumulative score of risk factors for early prediction of age-related hearing loss was 0.777 [95% CI (0.721, 0.833)]. The cumulative score threshold of risk factors was defined as 4, to classify the older adults into low-risk (< 4) and high-risk (≥ 4) hearing loss groups. The sensitivity, specificity, positive predictive value, and negative predictive value of the screen tool were 100%, 65.5%, 71.8%, and 100.0%, respectively. The Kappa index was 0.6. CONCLUSIONS: The screening software enabled the closed loop management of real-time data transmission, early warning, management, whole process supervision of the hearing loss and improve self-health belief in it. The software has huge prospects for application as a screening approach for age-related hearing loss.

Development of a Highly Permissive Mandarin Fish (Siniperca chuatsi) Kidney Cell Line for Mandarin Fish Ranavirus Using a Single-Cell Cloning Method.

Mandarin fish ranavirus (MRV) infection poses a substantial challenge to the mandarin fish culture industry as no effective preventive or therapeutic measures currently exist. The creation of a highly permissive cell line from a natural host is crucial for developing a vaccine for MRV and understanding its pathogenic mechanisms. In this research, the mandarin fish (Siniperca chuatsi) kidney cell line (SCK) was isolated from mandarin fish kidneys. Subsequently, SCK-a to SCK-g monoclonal cell lines were derived from the SCK cell population, distinguished by morphological variations. Notably, MRV infection induced an advanced cytopathic effect (CPE) in almost all cells of the SCK-f clone. Further tests showed that MRV achieved a peak viral titer of 1010.7 50% tissue culture infectious dose (TCID50)/mL and consistently exceeded 1010 TCID50/mL across nine passages in SCK-f cells. Electron microscopy verified the MRV virion integrity within SCK-f. In vivo experiments revealed that MRV infections led to cumulative mortality rates of 86.9% in mandarin fish and 88.9% in largemouth bass (Micropterus salmoides). Such results suggest that SCK-f is highly permissive to MRV. This study underscores the importance of cellular diversity in developing viral permissive cell lines. The SCK monoclonal cell line pool may offer potential for generating highly permissive cell lines for other mandarin fish viruses.

Tasks of COVID-19 prevention and control management teams at primary health care facilities in mainland China: a nationwide online cross-sectional survey.

BACKGROUND: This research aimed to investigate the tasks performed by Coronavirus Disease 2019(COVID-19) prevention and control management teams at primary healthcare (PHC) facilities during COVID-19 pandemic across the mainland China. METHODS: An online survey was performed and COVID-19 prevention and control management teams at PHC facilities were invited to participate in this research. The top 7 most important tasks in the three different periods of COVID-19 containment were selected and ranked. Participations of tasks were surveyed. RESULTS: A total of 998 valid responses (an effective rate of 99.11%) were collected. The respondents were divided into Group A (≤5 respondents within each PHC facility, n1 = 718) and Group B (> 5 respondents within each PHC facility, n2 = 280). The consensus was selected from top 7 most important tasks including screening at travel centers/intervals and screening at entry centers, at-home/centralized quarantine management, transferring, pre-examination/triage and fever sentinel surveillance clinic/fever clinic. Pre-examination/triage and fever sentinel surveillance clinic/fever clinic works became more significant in the regular prevention and control period. Adjusted analysis found that team members of Group A with a college, undergraduate college and graduate school educational background were less involved in pre-examination/triage works (aOR: 0.28; 95%CI: 0.09-0.86, P = 0.026; aOR: 0.30; 95%CI: 0.10-0.90, P = 0.031; aOR: 0.21; 95%CI: 0.05-0.82, P = 0.024). Those who were over the median age were twice more likely to be engaged in managing fever sentinel surveillance of clinic/fever clinic visitors (aOR: 2.18; 95%CI: 1.16-4.08, P = 0.015). Those being specialized in nursing and other specialties were less likely to participate in fever sentinel surveillance of clinic/fever clinic works (aOR: 0.44; 95%CI: 0.24-0.81, P = 0.009; aOR: 0.30; 95%CI: 0.16-0.58, P < 0.001). Those came from central and western China were less likely to participate in centralized quarantine management (aOR: 0.61; 95%CI: 0.38-0.98, P = 0.042; aOR: 0.64; 95%CI: 0.42-0.97, P = 0.037). Team members came from central and western China were twice less likely to participate in screening at travel centers/intervals (aOR: 1.75; 95%CI: 1.14-2.70, P = 0.011; aOR: 1.63; 95%CI: 1.07-2.48, P = 0.024). CONCLUSION: In mainland China, team members of COVID-19 prevention and control at PHC facilities are mainly responsible for screening, quarantine, transferring and monitoring during the COVID-19 pandemic. Pre-examination/triage and the fever sentinel surveillance clinic/fever clinic were gradually valued. Team members with lower educational background are competent in pre-examination/triage works, but more experienced general practitioners are more likely to be in charge of fever sentinel surveillance clinic/fever clinics work. The necessity of COVID-19 prevention and control management teams to participate in screening at travel centers/intervals is subjected to further discussions.

Vaccination coverage among COVID-19 prevention and control management teams at primary healthcare facilities in China and their attitudes towards COVID-19 vaccine: a cross-sectional online survey.

OBJECTIVE: To investigate the COVID-19 vaccination coverage rate and differences among various COVID-19 prevention primary healthcare (PHC) facilities in China and understand their attitudes towards COVID-19 vaccine. These findings are helpful to provide important suggestions to further improve national COVID-19 vaccination rate. DESIGN: A nationwide cross-sectional online survey was designed and conducted among COVID-19 prevention and control management teams at PHC facilities in mainland China. In the self-designed questionnaires, each subject was asked to evaluate on a 1-10 scale (10=extremely important/acceptable/influential) the COVID-19 vaccination importance, acceptance and factors related to vaccine hesitancy. SETTING: Subjects from 31 provinces and autonomous regions including minorities across mainland China were invited to complete the questionnaire between 22 February 2021 and 2 March 2021. PARTICIPANTS: Were selected by multistage stratified sampling, 998 valid questionnaires (valid rate 99.11%) were collected. The respondents were divided into group A (≤5 respondents within each PHC facility, n1=718) and group B (>5 respondents within each PHC facility, n2=280). OUTCOME MEASURES: Survey on vaccination rate and attitude towards COVID-19 vaccine included the following: (1) if the subjects think the vaccination is important in containment of COVID-19 pandemic (1-10 scale, 10=extremely important), (2) if they would accept COVID-19 vaccine (1-10 scale, 10=extremely acceptable) and (3) their opinions on 7 factors possibly related to vaccine hesitancy (1-10 scale, 10=extremely influential). All the items were designed based on the previous expert interviews. RESULTS: Our results showed vaccination rate was greater in group A (85.93%) than in group B (66.43%) (p<0.001). Detailed analyses revealed that in group A, male members were twice as likely to get vaccinated as compared with female members (adjusted OR (aOR): 2.07; 95% CI: 1.26 to 3.43, p=0.004). In group B, those who were at or under the median age had twice the odds of vaccination coverage compared with those who were over the median age (aOR: 2.29; 95% CI: 1.22 to 4.33, p=0.010). In addition, those who were specialised in traditional Chinese medicine were less likely to get vaccinated against COVID-19 compared with those who were specialised in general medicine, with the aOR: 0.10 (95% CI: 0.01 to 0.83, p=0.033). By analysing the factors that influenced the vaccination attitudes among the 998 respondents, we found no significant difference between the vaccinated and unvaccinated participants. However, further detailed analyses found that team members with undergraduate college education were less likely to score higher in COVID-19 vaccination importance than those with technical secondary school education (aOR: 0.35; 95% CI: 0.13 to 0.93, p=0.035); Furthermore, those with non-medical job titles had nearly twice the odds of giving a higher score for the uncertainty of vaccine efficacy compared with those with junior medical titles (aOR: 1.70; 95% CI: 1.02 to 2.85, p=0.016). Team members with a non-medical title were more likely to give a higher score for advice on social sources compared with those with a junior medical title (aOR: 1.70; 95% CI: 1.02 to 2.85, p=0.042). CONCLUSION: In PHC facilities, although there was a higher COVID-19 vaccination rate among COVID-19 prevention and control teams, some subgroups with different descriptive characters showed negative attitudes towards COVID-19 vaccination. Because primary care workers in China are highly expected to receive the vaccination, and support and educate the public for COVID-19 vaccination. Thus, it is important and necessary to continue to educate them about their vaccination concerns and change their attitudes towards vaccination. Our findings are highly beneficial for designing public vaccination education strategies.

Prevention and control of COVID-19 by primary health care facilities in China: a field-survey-based qualitative study in three typical cities.

BACKGROUND: During the coronavirus disease 2019 (COVID-19) containment, primary health care (PHC) facilities inChina played an important role in providing both healthcare and public care services to community populations. The tasks of COVID-19 containment facilitated by PHC facilities were different among different regions and during different periods of COVID-19 pandemic. We sought to investigate the gaps on task participation, explore existing problems and provide corresponding solutions. METHODS: Semi-structured face-to-face interviews with COVID-19 prevention and control management teams of PHC facilities were conducted. Purposive stratified sampling was used and 32 team members of 22 PHC facilities were selected from Wuhan (as high-risk city), Shanghai (as medium-risk city) and Zunyi (as low-risk city). Framework analysis was employed to analyze the transcribed recordings. RESULTS: The main tasks of PHC facilities during the early period of the pandemic included assisting in contact tracing and epidemiological investigation, screening of populations at high-risk at travel centers/internals, house-by-house, or pre-examination/triage within PHC facilities; at-home/ centralized quarantine management; the work of fever sentinel clinics. Further analyses revealed the existing problems and suggestions for improvement or resolutions. Regular medical supply reserves were recommended because of the medical supply shortage during the pre-outbreak period. Temporarily converted quarantine wards and centralized quarantine centers could be used to deal with pressures on patients' treatment and management of the febrile patients. Only after strict evaluation of nucleic acid testing (NAT) results and housing conditions, decision on quarantine at-home or centralized quarantine centers could be made. Settings of fever sentinel clinics at PHC facilities allowed fever patients with no COVID-19 infection risks for treatment without being transferred to fever clinics of the designed secondary hospitals. Psychological intervention was sometimes in need and really helped in addressing individuals' mental pressures. CONCLUSIONS: During the COVID-19 containment, PHC facilities in China were responsible for different tasks and several problems were encountered in the working process. Accordingly, specific and feasible suggestions were put forward for different problems. Our findings are highly beneficial for healthcare teams and governments in handling similar situations.

Rheumatoid arthritis drug sinomenine induces apoptosis of cervical tumor cells by targeting thioredoxin reductase in vitro and in vivo.

Overexpression of thioredoxin reductase (TrxR) has been linked to tumorigenesis and phenotypic maintenance of malignant tumors. Thus, targeting TrxR with natural molecules is a promising strategy for developing anticancer drugs. Sinomenine is a naturally occurring alkaloid isolated from Sinomenium acutum. The drug, Zhengqing Fengtongning made from sinomenine, has been universally applied in rheumatoid arthritis treatment in China as well as other Asian countries for decades. Recently, increasing evidence indicates that sinomenine appears to be a promising therapeutic agent against various cancer cells. However, the exact mechanism underlying the anticancer activity of sinomenine remains unclear. In this study, we identified sinomenine as a kind of new inhibitor for TrxR. Pharmacological inhibition of TrxR by sinomenine results in the decrease of thiols content, increases the levels of reactive oxygen species, and finally facilitates oxidative stress-mediated cancer cell apoptosis. It is vital that knockdown in TrxR1 by shRNA can increase cell sensitivity to sinomenine. Treatment with sinomenine in vivo leads to a decrease in TrxR activity and tumor growth, and an increase in apoptosis. Our findings provide a novel action mechanism related to sinomenine and presents an insight on how to develop sinomenine as a chemotherapeutic agent for cancer therapy.

Transport of mercury in a regulated high-sediment river and its input to marginal seas.

Seafood is a major source of Hg exposure for humans, and rivers are an important source of Hg for adjacent seas. The Yellow River is an extremely high-sediment river that is heavily influenced by anthropogenic water facilities, especially sediment regulations, which might result in significant intra- and inter- year flux variations on pollutants. Overestimations of Hg flux were found in previous studies on high-sediment rivers, and a comprehensive study of Hg transport along such a river has not yet been attempted. In this study, we quantified the fates of Hg and methylmercury (MeHg) in the Yellow River and its main branches, as well as the impacts of anthropogenic activities, including deposition of contaminants in the reservoirs, diversion in the downstream, and sediment regulation, by sampling in 2017 and 2018,and comparing the two typical years with and without sediment regulation. The total Hg (THg) and MeHg concentrations in the Yellow River and its tributaries were high, and extremely high MeHg/THg ratios were found in the three sampled reservoirs. The river discharges substantial amounts of THg and MeHg into the Bohai Sea, and particulate Hg in the humid period accounts for a large proportion. A significant increase in Hg flux into the ocean was found in 2018 compared with that in 2017, which was primarily attributed to the altered hydrology caused by sediment regulation. Substantial amounts of Hg were impounded in the reservoirs, and only a small fraction was discharged downstream of the reservoir in the non-regulation years. Moreover, Hg fluxes to the coastal ocean were impacted by downstream water diversion in non-regulation years, whereas the contributions of diversions in regulation years were small. In conclusion, models showed that in recent 15 years, sediment regulation can enhance the Hg burden and risk to coastal ecosystem of Bohai Sea.

Natural diterpenoid eriocalyxin B covalently modifies glutathione and selectively inhibits thioredoxin reductase inducing potent oxidative stress-mediated apoptosis in colorectal carcinoma RKO cells.

Increasing evidence suggests the significant contribution of high levels of thioredoxin reductase (TrxR) in various stages of tumorigenesis and resistance to tumor chemotherapy. Thus, inhibition of TrxR with small molecules is an attractive strategy for cancer therapy. Eriocalyxin B (EriB), a naturally occurring diterpenoid extracted from Isodon eriocalyx, has reflected potential anticancer activities through numerous pathways. Here, we describe that EriB covalently modifies GSH and selectively inhibits TrxR activity by targeting the Sec residue of the enzyme. Pharmacological inhibition of TrxR by EriB results in elevated ROS levels, reduced total GSH and thiols content, which ultimately induced potent RKO cell apoptosis mediated by oxidative stress. Importantly, EriB indicates potent synthetic lethality with GSH inhibitors, BSO, in RKO cells. In summary, our results highlight that targeting TrxR by EriB explores a novel mechanism for the biological action of EriB. This opened up a new therapeutic indication for using EriB to combat cancers.

Mastery of type 2 diabetes prevention and treatment knowledge by general practitioners in Shanghai: a cross-sectional study.

BACKGROUND: To study the competency of general practitioners (GPs) in Shanghai, China on prevention and management of type 2 diabetes, also understand factors that may prohibit it. METHODS: A survey questionnaire with 25 questions was designed based on 2013 Chinese Type 2 Diabetes Prevention Guidelines and Chinese Type 2 Diabetes Prevention Guidelines (Grassroots Edition) and conducted among 789 GPs who work at 54 community healthcare centers (CHCs) within 16 districts at Shanghai, China. Excel 2016 and SPSS 24.0 were used for data analysis, and a difference of P < 0.05 was considered to be statistically significant. RESULTS: The GPs did poorly on three aspect of diabetes prevention and treatment: (1) treatment goals in elderly patients, (2) screening methods for high-risk population, and (3) aspirin contraindications. The statistical analysis data showed that GPs who finished standardized training had correct answer on 13.58 ± 3.31 questions out of total 25, with mean accuracy rate of 54.32%. Except the questions for high-risk population screening method and the diagnostic criteria for type 2 diabetes, there was no difference in the accuracy of other questions between GPs with or without standardized training (P < 0.05). However, sex, educational level, and subspecialty experience are affective factors on their competency in type 2 diabetes prevention and treatment knowledge. CONCLUSION: The results indicated that communities should strengthen the training of GPs in diabetes management and bidirectional referral. Frequent continuing education and skills training should be provided among GPs at CHCs to ensure their competency of type 2 diabetes prevention and treatment knowledge after obtaining their GP license disregard of their standardized training. In addition, attention should be paid to GPs who had lower education background or non-clinical subspecialty experience to strengthen their clinical knowledge of type 2 diabetes.

Mercury and methylmercury in China's lake sediments and first estimation of mercury burial fluxes.

Lake sediments are key materials for mercury deposition and methylation. To understand the mercury concentrations in China's lakes, 100 lake surface sediment samples were collected from 35 lakes in 2014. Total mercury (THg), methylmercury (MeHg) concentrations and the annual Hg burial rates in lake sediments were measured. THg and MeHg concentrations in the sediment ranged from 13.6 to 1488 ng‧g-1 and 0.05 to 1.70 ng‧g-1, respectively, and urban lakes reported most high values, indicating direct anthropogenic inputs. The Inner Mongolia-Xinjiang Region (MX) and Qinghai-Tibet Plateau Region (QT) reported relatively lower mercury burial rates, while the Eastern Plain Region (EP), Northeast Mountain and Plain Region (NE), and Yunnan-Guizhou Plateau Region (YG) reported higher mercury burial rates. Regional variances of THg burial fluxes were dominated by atmospheric deposition, terrestrial input, and sediment accumulation rates in different lakes. In 2014, the estimated average THg burial rate in China's lakes was 139 µg‧m-2‧yr-1, comparable to the average in mid-latitude North America in recent years; however, due to China's much smaller lake area relative to NA, the annual THg burial flux in China was much lower than that in North America. EP and NE, where most freshwater aquatic products in China are harvested, accounted for 58.2% and 22.9%, respectively, of the THg burial flux. High sedimentary MeHg concentrations and MeHg:THg ratios were reported in most of the NE but low MeHg concentrations and MeHg:THg ratios were reported in EP. MeHg concentrations and MeHg:THg ratios were positively correlated with water COD levels and negatively correlated with average temperature. The results of this study indicate that in addition to the adjacent seas, lake sediments are an important mercury sink in China's aquatic environment, which could cause health risks due to MeHg intake, especially in NE.

Visible-Light-Induced Cyclization/Aromatization of 2-Vinyloxy Arylalkynes: Synthesis of Thio-Substituted Dibenzofuran Derivatives.

A visible-light-induced cascade reaction of 2-vinyloxy arylalkynes with thiosulfonates was developed and provided unexpected thio-substituted dibenzofuran derivatives in moderate yields. Mechanistic studies revealed the thiosulfonylation product of 2-vinyloxy arylalkyne was the key intermediate, and the additive disulfide played the role of hydrogen abstraction in the aromatization process to offer the desired product. This reaction presents a new reaction mode for the construction of polycyclic oxygen heterocycles.

Influence of Cd exposure on H+ and Cd2+ fluxes in the leaf, stem and root of a novel aquatic hyperaccumulator - Microsorum pteropus.

Microsorum pteropus has been proven to be a potential novel aquatic Cd hyperaccumulator. In this study, Non-invasive Micro-test Technology (NMT) was used to observe the ion fluxes of different M. pteropus tissues under Cd exposure. M. pteropus can hyperaccumulate more than 1000 mg/kg Cd in roots and leaves and approximately 600 mg/kg Cd in stems after seven days of exposure to 500 µM Cd, showing that this plant have a great capacity for Cd enrichment and resistance. The NMT test found H+ fluxes increased in all tissues after Cd exposure, with the largest increases being observed in stems, followed by the leaves and roots. Cd2+ fluxes showed different accumulation levels in different tissues, with low-level Cd exposure leading to influxes into roots and leaves, and high-level Cd exposure resulting in effluxes from roots. No significant influxes or effluxes were observed in leaves under high-level Cd exposure, or in stems under low- and high-levels of Cd exposure. However, transient high-level Cd exposure showed long-term Cd2+ influxes into roots and short-term Cd2+ effluxes out of stems and leaves. The roots of M. pteropus had greater regulation mechanisms for Cd enrichment and resistance, with influxes occurring following low-level exposure and effluxes occurring from high-level exposure. When exposed to Cd, M. pteropus stems showed less transportation and absorption. Low-level Cd exposure resulted in individual leaves directly absorbing Cd from hydroponic solutions. Different Cd enrichment and resistance mechanisms were exhibited by different M. pteropus tissues.

Subcellular distribution of cadmium in a novel potential aquatic hyperaccumulator - Microsorum pteropus.

Microsorum pteropus is a novel potential Cd (cadmium) aquatic hyperaccumulator. In the present study, hydroponic experiments were conducted to assess the accumulation and subcellular distribution of Cd in the root, stem and leaf of M. pteropus. SEM (scanning electron microscopy) - EDX (energy dispersive X-ray fluorescence spectrometer) and TEM (transmission electron microscopy) were used to observe the ultrastructure of different tissues under 500 µM Cd exposure. After exposure to 500 µM Cd for 7 days, the root, stem and leaf of M. pteropus can accumulate to be > 400 mg/kg Cd in dry mass with no significant influence on the growth. In the root and leaf of M. pteropus, the Cd was more likely to store in the cell wall fraction. However, Cd in the stem was mainly stored in both the cell wall fraction and the cytoplasm fraction. Under SEM observation and EDX detection, 1) Cd was found to be sequestrated in the epidermis or chelated in the root cells, 2) no significant deposit spots were observed in the stem, 3) Cd was found in the trichome of the leaf, and the sporangium was not damaged. TEM observations revealed 1) possible Cd precipitations in the root cell and 2) no significant ultrastructure variation in the stem, and 3) the chloroplast retained its structure and was not affected by the Cd. M. pteropus showed great capacity for Cd accumulation without influencing growth. In addition, the ultrastructure of all the tissues was not damaged by the Cd. M. pteropus showed a great potential in phytoremediation in heavy metal polluted water solutions, and may provide new directions for the study of resistance mechanisms of aquatic hyperaccumulators.

Cadmium accumulation capacity and resistance strategies of a cadmium-hypertolerant fern - Microsorum fortunei.

Microsorum fortunei (M. fortunei), a close relative to the cadmium (Cd) hyperaccumulator Microsorum pteropus, is an epiphytic Polypodiaceae fern with strong antioxidant activity. The Cd-accumulation capacities and Cd-resistance mechanisms of M. fortunei were analyzed in this study by measuring metal contents (Cd, Fe, Mg, Ca, Zn, Mn, K and Na) and chlorophyll fluorescence parameters (Fv/Fm, qN, qP, Y(II), Y(NPQ) and Y(NO)) and by performing an RNA-sequencing analysis. M. fortunei could accumulate up to 2249.10 µg/g DW Cd in roots under a 15-day 1000 µmol/L Cd treatment, with little Cd translocated into the leaves (maximum 138.26 µg/g DW). The M. fortunei leaves could maintain their normal physiological functions with no phytosynthesis damage and few changes in metal contents or differentially expressed genes. M. fortunei roots showed a decrease in Zn concentration, with potential Cd-tolerance mechanisms such as heavy metal transporters, vesicle trafficking and fusion proteins, antioxidant systems, and primary metabolites like plant hormones, revealed by differentially expressed functional genes. In conclusion, M. fortunei may serve as a potential cadmium-hypertolerant fern that sequesters and detoxifies most cadmium in the roots, with a minimum root-to-shoot Cd translocation to guarantee the physiological functions in the more vulnerable leaves.

Differential expression of proteins in the leaves and roots of cadmium-stressed Microsorum pteropus, a novel potential aquatic cadmium hyperaccumulator.

Microsorum pteropus is a fully or partially submerged Polypodiaceae fern that has been proven to be a potential Cd aquatic hyperaccumulator. Proteomic analysis was used in this study to investigate the resistance mechanisms of M. pteropus root and leaf tissues under Cd stress. M. pteropus plants were exposed to up to 500 µM Cd in hydroponics for 7 days. The plant can accumulate >4,000 mg/kg Cd in both root and leaf dry mass. Meanwhile, the proteins in roots and leaves in the 500 µM Cd treatment were separated and analyzed by proteomics. Eight proteins with altered expression in roots and twenty proteins with altered expression in leaves were identified using MALDI-TOF/TOF-MS (matrix-assisted laser desorption/ionization time of flight mass spectrometry) in this study. The proteins were involved in energy metabolism, antioxidant activity, cellular metabolism and protein metabolism. However, just three proteins were significantly differentially expressed in both tissues, and they were all involved in basal metabolism, indicating different resistance mechanisms between roots and leaves. Root tissues of M. pteropus mainly resist Cd damage by antioxidants and the enhancement of energy metabolism, while leaf tissues of M. pteropus mainly protect themselves by maintaining photosynthetic functions and the regulation of cellular metabolism.

Comparisons of cadmium bioaccumulation potentials and resistance physiology of Microsorum pteropus and Echinodorus grisebachii.

To better monitor and remediate environments contaminated by cadmium (Cd), plants are used as hyperaccumulators or biomonitors; however, few have been identified for aquatic Cd pollution. In our study, two aquatic ornamental plants, Microsorum pteropus (Blume) Copel. and Echinodorus grisebachii Small, were studied for their Cd accumulation capacity, morphological characteristics, and leaf physiological indexes. Microsorum pteropus (Blume) Copel. leaf has the potential to hyperaccumulate Cd (166 mg/kg dry weight for 1 mg/L exposure), with no significant physiological difference under exposure. Echinodorus grisebachii Small had sensitive diagnostic responses to Cd toxicity, such as significant decreases in Chl (a + b) and Chl-a/b, increased peroxidase (POD) activity, greater malondialdehyde (MDA) content, and increased soluble sugar content. These results suggest that Microsorum pteropus (Blume) Copel. could have the potential to be a Cd hyperaccumulator, while Echinodorus grisebachii Small could serve as a biomonitor for Cd-contaminated water bodies.

Resistance mechanisms and their difference between the root and leaf of Microsorum pteropus - A novel potential aquatic cadmium hyperaccumulator.

Microsorum pteropus (M. pteropus), an aquatic Polypodiaceae fern, was identified as a novel potential cadmium (Cd) hyperaccumulator in our previous study. This study reveals the Cd-resistance mechanisms and their difference between the root and leaf of M. pteropus based on analyses of photosynthesis, antioxidant systems and gene expression. A high level of Cd at 500µM was used to treat the samples to test the effects of this compound. Superoxide dismutase (SOD), peroxidase (POD), malondialdehyde (MDA) and flavonoids were used as indicators for antioxidant system changes. Five chlorophyll fluorescent parameters including the maximal photochemical efficiency of photosystem II (Fv/Fm), effective quantum yield of photosystem II (Y(II)), photochemical quenching (qP), nonphotochemical quenching (qN) and electron transport rate (ETR) were measured to determine the photosynthetic changes. RNA-sequencing analysis was used to study the changes in gene expression. The results showed that after exposure to high levels of Cd, the concentrations of enzymatic oxidants (SOD and POD) were significantly increased, while the MDA levels were significantly decreased. There were no significant changes for the chlorophyll fluorescent parameters during Cd stress, which indicates that M. pteropus is highly effective at protecting itself. Certain functional genes, including photosystem genes and secondary metabolites, had significantly altered levels of expression. Different Cd-resistance mechanisms were found between the root and leaf tissues of M. pteropus. The root tissues of M. pteropus resist Cd damage using antioxidants, while its leaf tissues mainly protect themselves using photosystem self-protection.

Synthesis of Polycarbonyl Pyrroles via K2S2O8-Mediated Oxidative Cyclization of Enamines.

A novel K2S2O8-promoted oxidative cyclization of enamines is described. A variety of enamines having diverse functional groups and substitution patterns react well using K2S2O8 as the oxidant in the absence of catalyst. This protocol provides a very simple route for the synthesis of polycarbonyl pyrroles and has the advantages of readily available starting materials, mild reaction conditions, and a wide scope of substrates.

Organocatalytic asymmetric conjugate addition and cascade acyl transfer reaction of α-nitroketones.

Organocatalytic asymmetric conjugate addition of α-nitroketones to ß,γ-unsaturated α-keto esters has been developed. A pyrrolidine-based thiourea-tertiary amine was identified as the best catalyst. The reaction was found to proceed via cascade conjugate addition and acyl transfer reaction. A number of α-nitroketones and ß,γ-unsaturated α-keto esters were examined in this transformation. 5-Nitro-2-acyloxypent-2-enoates were obtained in good yields (up to 99%) and enantioselectivities (up to 99% ee). The products could be hydrolyzed to provide 5-nitro-2-oxopentanoates, which are not available from the direct addition of nitromethane to ß,γ-unsaturated α-keto esters.