Isolation and Electrochemical Analysis of a Facultative Anaerobic Electrogenic Strain Klebsiella sp. SQ-1.

Electricigens decompose organic matter and convert stored chemical energy into electrical energy through extracellular electron transfer. They are significant biocatalysts for microbial fuel cells with practical applications in green energy generation, effluent treatment, and bioremediation. A facultative anaerobic electrogenic strain SQ-1 is isolated from sludge in a biotechnology factory. The strain SQ-1 is a close relative of Klebsiella variicola. Multilayered biofilms form on the surface of a carbon electrode after the isolated bacteria are inoculated into a microbial fuel cell device. This strain produces high current densities of 625 µA cm-2 by using acetate as the carbon source in a three-electrode configuration. The electricity generation performance is also analyzed in a dual-chamber microbial fuel cell. It reaches a maximum power density of 560 mW m-2 when the corresponding output voltage is 0.59 V. The facultative strain SQ-1 utilizes hydrous ferric oxide as an electron acceptor to perform extracellular electricigenic respiration in anaerobic conditions. Since facultative strains possess better properties than anaerobic strains, Klebsiella sp. SQ-1 may be a promising exoelectrogenic strain for applications in microbial electrochemistry.

Ca-driven stable regulatory of alkalinity within desilication products: Experimental, modeling, transformation mechanism and DFT study.

The prevalent pH rebound phenomenon in the bauxite residue alkalinity regulation is primarily caused by the presence of alkaline minerals, including sodalite and cancrinite. Calcium ion is widely used to remove the free alkali for reducing the alkalinity of bauxite residue, but its underlying mechanism on alkaline minerals is still unclear. In this work, we investigated the action mechanism of calcium ion on sodalite and cancrinite by various microspectroscopic methods, and then employed spin-polarized density functional theory (DFT) calculations to reveal the reaction pathways of calcium ion substitution and migration in minerals. The calcium ion can effectively regulate the stability of alkaline minerals by inhibiting alkaline ions release, which respectively enters sodalite and cancrinite by displacing Na adsorbed inside the mineral lattice and on the mineral surface. The entered calcium ion acts as competitive protection against sodium during the neutralization process, thus inhibiting the proton-promoted dissolution of sodalite and cancrinite. Moreover, the amount of entry calcium ion controls their acid neutralization ability. DFT calculations revealed calcium ions readily replaced sodium on the internal channels of minerals rather than on the surface. These new findings contribute to the understanding of potential options to directly stabilize critical alkaline components in bauxite residue.

Hedyotis diffusa alleviate aflatoxin B1-induced liver injury in ducks by mediating Nrf2 signaling pathway.

Aflatoxin B1 (AFB1), the most harmful aflatoxins, is a frequent contamination in feed and food items, raising global concerns in animal production and human public health. Also, AFB1 induces oxidative stress, cytotoxicity, mutations, and DNA lesions through its metabolic transformation into aflatoxin B1-8,9-epoxide (AFBO) by cytochrome P450 (CYP450). Hedyotis diffusa (HD) is a traditional Chinese herbal medicine known for its multiple pharmacological activities, including antioxidant, anti-inflammatory, and immunomodulatory. Yet, the influence of HD on AFB1-induced liver injury in ducks is still unknown. Here, we investigated whether HD positively affects AFB1-induced liver injury in ducks. Results revealed that I) AFB1 caused significant changes in serum biochemical indices and decreased growth performance of ducks (such as ALT, AST, ALP, TP, ALB, final body weight, and body weight gain), whereas HD supplementation at 200 mg/kg mitigated these alterations. II) HD alleviated hepatic histopathological changes and liver index induced by AFB1 in ducks. III) HD significantly attenuated AFB1-induced oxidative stress, as measured by increased antioxidant enzyme activities such as SOD, GPx, and T-AOC and decreased MDA levels. Furthermore, HD reduced the level of AFB1-DNA adduct in duck liver. IV) HD significantly promoted the transcriptional expression of NF-E2-related nuclear factor 2 (Nrf2) and associated genes, including heme oxygenase 1 (HO-1), NAD(P)H dehydrogenase quinone 1 (NQO1), glutamate-cysteine ligase catalytic (GCLC). In conclusion, these results demonstrated that HD could activate the Nrf2 pathway in ducks to reduce the hepatotoxicity driven by AFB1. This finding also provides theoretical and data support for a deeper understanding of the toxic mechanisms of AFB1 and its prevention.

Prevalence of myopia and uncorrected myopia among 721 032 schoolchildren in a city-wide vision screening in southern China: the Shantou Myopia Study.

AIMS: To explore the prevalence and risk factors for myopia and uncorrected myopia in schoolchildren in southern China. METHODS: The government-led Shantou Myopia Study was conducted from September 2020 to June 2021. Non-cycloplegic refraction was performed. Uncorrected visual acuity (UCVA) was measured along with presenting visual acuity if participants wore spectacles. Spherical equivalent refraction (SER) is defined as the spherical dioptres added to half of the cylindrical dioptres. Myopia is defined as SER <-0.50 dioptre with UCVA of <20/20 in at least one eye. RESULTS: This study enrolled 724 828 schoolchildren (77.8% of all schoolchildren in Shantou) from 901 schools. Data from 721 032 schoolchildren (99.5%) were analysed (mean age 11.53±3.13 years, 6-20 years, 373 230 boys and 347 802 girls). Among them, 373 459 (51.8%) had myopia: 37.1% of 465 696 children in primary schools, 75.4% of 170 164 children in junior high schools and 84.8% of 85 172 children in senior high schools. The prevalence of myopia increases non-linearly with age. Older age, female and urban living environment were independently associated with myopia prevalence and myopic SER. Among the 373 459 children with myopia, 60.0% had no refractive correction: 74.9%, 53.9% and 35.5% in primary, junior high and senior high schools, respectively. CONCLUSION: The overall prevalence of myopia among schoolchildren in Shantou was 51.8%, higher than the national average in China. The proportion of uncorrected myopia is high, especially in primary schools. Our results indicate the need for public education on eye care among schoolchildren even in a municipal city.

Excess and Defect: How Job-Family Responsibilities Congruence Effect the Employee Procrastination Behavior.

Purpose: Prior work suggests that responsibility is negatively associated with employee procrastination behavior. Based on the conservation of resources (COR) theory, we suggest this view is oversimplified and propose that procrastination can be induced when employees have congruent job and family responsibilities via the mediating effect of emotional exhaustion. Methods: This is a quantitative study of the configurational approach. Survey data were collected from 323 employees at two stages in southern Chinese internet enterprises in September 2020. A randomized cluster sample was used and an anonymous self-assessment questionnaire was distributed to all selected respondents (employees). Samples involved different departments, and the procrastination phenomenon is more significant among them. SPSS20.2 and MPLUS 8.3 software and Response Surface Analysis Strategy were used to test the hypotheses. Results: The data analysis results indicated that: a) employee procrastination behavior is higher when employees' job responsibility and family responsibility are congruent than the incongruent configurations. b) Procrastination is lower when job-family dyads are congruent at high levels of responsibility compared the low levels. c) Procrastination decreases as employees' job and family responsibilities become more discrepant (ie, incongruent); employees with low job-high family responsibilities procrastinate more than those with high job-low family responsibilities. d) Additionally, employee-experienced emotional exhaustion mediates the relationship in four configurations between job-family responsibilities congruence and procrastination behavior. Conclusion: Drawing on the conservation of resources theory, we proposed a model clarifying how varying combinations of job and family responsibilities affect employee procrastination behavior. The results showed that there are significant differences in the impact of different job-family responsibility combinations on employee procrastination behavior. Employee procrastination behavior is higher when employees' job-family responsibility are congruent than the incongruent configurations. Additionally, employee-experienced emotional exhaustion mediates the relationship in four configurations between job-family responsibilities congruence and procrastination behavior.

Prevalence of Visual Impairment in Preschool Children in Southern China.

Purpose: The goal of this study is to assess the prevalence and distribution of visual impairment in preschool children in southern China. Methods: Preschool children aged 36-83 months were enrolled in a vision screening program in Shantou City. Visual acuity test and non-cycloplegic refraction were conducted. According to the American Academy of Ophthalmology (AAO) guidelines, visual impairment was defined as uncorrected visual acuity (UCVA) in either eye <20/50, 20/40, and 20/32 in children aged 36-47, 48-59, and 60-83 months, respectively, as well as an interocular difference (IOD) of ≥ two lines of UCVA. Results: The UCVA test was successfully performed on 7,880 children (94.6% of the enrolled population). A total of 938 (11.9%; 95% CI 11.2-12.6) children were found to have reduced UCVA in the worse eye, and 393 (5%; 95% CI 4.5-5.5) of the children had an IOD of two or more lines. Combining the reduced UCVA with the IOD criteria identified 1,032 (13.1%; 95% CI 12.4-13.8) children with visual impairment. UCVA in preschool children improves with age naturally and boys have slightly better age-adjusted UCVA than girls. Causes of reduced visual acuity included uncorrected refractive error, amblyopia, congenital cataract, and others. The cylindrical diopter in the right eye of children with reduced vison was higher than that of children with normal vision (1.19 ± 1.05 vs. 0.52 ± 0.49, P < 0.001). A total of 146 (1.9%, 95% CI 1.6-2.2) of the preschool children wore spectacles. The proportion of wearing spectacles increased with age (χ2 = 35.714, P < 0.001), but with IOD increasing by.1 logMAR, the odds of wearing spectacles decreased by 44.8%. Conclusion: This study provided data on the prevalence of visual impairment in preschool children in China by large-scale school-based vision screening. Further studies should be conducted to verify the benefit from vision screening.

Sulfonated calix[4]arene functionalized SiO2@TiO2 for recognition of lysine methylation.

Lysine methylations are common protein post-translational modifications (PTMs), that play significant roles in regulating gene activities. Studies of their functions and connections with diseases have important values. However, due to the small variations from their native structures and very low component proportions, it is very difficult to extract methylated peptides from biological mixtures. In this research, a new material that utilizes sulfonated calix[4]arene (SC4A) as the recognition unit and silica coated with TiO2 as carrier, denoted as SiO2@TiO2@SC4A, was synthesized. The equilibrium binding experiments demonstrated that SiO2@TiO2@SC4A can identify lysine and arginine methylation and peptides with these methylated residues. The maximum isotherm binding capacities are 70.0, 55.9, 31.4 and 24.8 µmol g-1 for Lys(Me3), Lys(Me)2, Lys(Me) and Lys, respectively. It demonstrated that the higher the degree of methylation, the stronger the interactions. In addition, the analyses of high performance liquid chromatography (HPLC) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) demonstrated that peptides with methylated lysine or arginine can be selectively extracted from spiked histone trypsin digestion. The recoveries for the spiked GGAK(Me)R, GGAKR(Me)2 and GGAK(Me)3R are 83%, 78%, and 84% respectively. The experiments from the nuclear extracts of HeLa cells also illustrated that SiO2@TiO2@SC4A holds a potential in the enrichment and identification of lysine methylations.

Acupoint combination effect of Shenmen (HT 7) and Sanyinjiao (SP 6) in treating insomnia: study protocol for a randomized controlled trial.

BACKGROUND: Insomnia is a global disease with a high incidence and acupuncture therapy is a well appropriate method to treat insomnia. Shenmen (HT 7) and Sanyinjiao (SP 6) are the acupoints most commonly used to treat insomnia. Although they can obviously relieve the clinical symptoms of insomnia, it is unclear whether they must be used together, whether the combination of two acupoints may have a synergistic or antagonistic effect, and whether there is a primary or secondary relationship between the two points in the treatment of insomnia. Further studies are needed. Therefore, in this study, we are exploring the acupoint combination effect and biological mechanism of HT 7 and SP 6 in treating insomnia. METHODS/DESIGN: This will be a parallel group randomized controlled trial. The study will recruit 120 patients with insomnia randomly assigned to a control group, an electroacupuncture on HT 7 group, an electroacupuncture on SP 6 group, and an electroacupuncture on HT 7 and SP 6 group. The allocation ratio is 1:1:1:1, with 30 subjects in each group. Meanwhile, ten healthy subjects who meet the study criteria will be recruited as the healthy control group. Patients in the intervention groups will be given ten rounds of electroacupuncture stimulation on the corresponding acupoints for 2 weeks, five times per week, with 2 days of rest between the two treatment courses. Patients in the control group will also receive the same two courses of ten rounds of compensatory acupuncture therapy after a 2-week waiting period for treatment. The major outcome measures of this study include the Sleep Dysfunction Rating Scale, the Insomnia Severity Index, Epworth Sleepiness Scale, the Zung Self-Rating Anxiety Scale, and the Zung Self-Rating Depression Scale, combined with the Measure Your Medical Outcome Profile, to evaluate insomnia and the emotional state of patients with insomnia. The secondary outcome measures include sleep composition monitored by polysomnography and measurements of acetylcholine, serotonin, dopamine, norepinephrine, melatonin, gamma-aminobutyric acid, and metabolic biomarkers in serum. DISCUSSION: In this study, we are exploring the acupoint combination effect and biological mechanism of HT 7 and SP 6 in treating insomnia, which may provide evidence for the clinical application of acupuncture and acupoint selection in the treatment of insomnia. TRIAL REGISTRATION: Chinese Clinical Trial Registry, Chi-CTR-1800017483. Registered on 1 August 2018.

Electricity production of microbial fuel cells by degrading cellulose coupling with Cr(VI) removal.

A facultative exoelectrogen strain Lsc-8 belonging to the Cellulomonas genus with the ability to degrade carboxymethyl cellulose (CMC) coupled with the reduction of Cr(VI), was successfully isolated from rumen content. The maximum output power density of the microbial fuel cells (MFCs) inoculated strain Lsc-8 was 9.56 ±â€¯0.37 mW·m-2 with CMC as the sole carbon source. From the biomass analysis it can be seen that the electricity generation of the MFCs was primarily attributed to the planktonic cells of strain Lsc-8 rather than the biofilm attached on the electrode, which was different from Geobacter sulfurreducens. Especially, during electricity generation of the MFCs using CMC as carbon source in the anode chamber, the Cr(VI) reduction were simultaneously realized. And it is also found that the Cr(VI) reduction ratio by strain Lsc-8 is directly related to the initial Cr(VI) concentration, and it increased with the increase of initial Cr(VI) concentration at first, then started to decrease when the Cr(VI) concentration was above 21 mg ·L-1. Meanwhile, the highest output power density of 3.47 ±â€¯0.28 mW·m-2 was observed coupling with 95.22 ±â€¯2.72 % of Cr(VI) reduction. These data suggested that the strain Lsc-8 could reduce high toxicity Cr(VI) to low toxicity Cr(III) coupled with electricity generation in MFCs with CMC as the carbon source. Our results also suggested that this study will provide a possibility to simultaneously degrade Cr(VI) and generate electricity by using cellulose as the carbon source via MFCs.

Optimization of culture conditions for differentiation of melon based on artificial neural network and genetic algorithm.

Artificial neural network is an efficient and accurate fitting method. It has the function of self-learning, which is particularly important for prediction, and it could take advantage of the computer's high-speed computing capabilities and find the optimal solution quickly. In this paper, four culture conditions: agar concentration, light time, culture temperature, and humidity were selected. And a three-layer neural network was used to predict the differentiation rate of melon under these four conditions. Ten-fold cross validation revealed that the optimal back propagation neural network was established with traingdx as the training function and the final architecture of 4-3-1 (four neurons in the input layer, three neurons in the hidden layer and one neuron in the output layer), which yielded a high coefficient of correlation (R2, 0.9637) between the actual and predicted outputs, and a root-mean-square error (RMSE) of 0.0108, suggesting that the artificial neural network worked well. According to the optimal culture conditions generated by genetic algorithm, tissue culture experiments had been carried out. The results showed that the actual differentiation rate of melon reached 90.53%, and only 1.59% lower than the predicted value of genetic algorithm. It was better than the optimization by response surface methodology, which the predicted induced differentiation rate is 86.04%, the actual value is 83.62%, and was 2.89% lower than the predicted value. It can be inferred that the combination of artificial neural network and genetic algorithm can optimize the plant tissue culture conditions well and with high prediction accuracy, and this method will have a good application prospect in other biological experiments.

Enhanced catalytic capability of electroactive biofilm modified with different kinds of carbon nanotubes.

In this study two methods including coating carbon nanotubes (CNTs) layers on the electrode surface and adding CNTs-suspension during electrochemically active biofilms (EABs) growth were used, respectively, to develop CNTs hybrid EABs for enhancing electricity generation capability of EABs. EABs growth on the CNTs with functional groups of hydroxyl (CNTs-OH) or carboxyl (CNTs-COOH) and pristine CNTs without functionalization (P-CNTs) modified electrode was investigated. The maximum current densities of EABs growth on the P-CNTs, CNTs-OH and CNTs-COOH coated electrode were respective 1300 ±â€¯117, 1082 ±â€¯54 and 1124 ±â€¯78 µA cm-2, which were much higher than unmodified electrode (663 µA cm-2). Meanwhile, EABs growth in doping CNTs-COOH or CNTs-OH suspensions system also produced twice higher current density than that on unmodified electrode. These results indicated that the current production of EABs can be significantly enhanced by coating P-CNTs, CNTs-OH, CNTs-COOH layers on the electrode surface or doping CNTs-OH and CNTs-COOH suspension into EABs. Furthermore, morphology analysis of as-obtained EABs had also been studied. It was found that there was no significant difference of the morphological characteristic for EABs growth on different types CNTs coated electrode surface. By comparison, a nano-hybrid porous structure of CNTs and EABs was observed when CNTs-COOH or CNTs-OH suspension was added into the medium during EABs growth, which will be responsible for high current generation.

Preparation of an epitope-imprinted polymer with antibody-like selectivity for beta2-microglobulin and application in serum sample analysis with a facile method of on-line solid-phase extraction coupling with high performance liquid chromatography.

Molecularly imprinted polymers (MIPs) for protein recognition have great application potential in the biological analysis. However, preparation of protein imprinted polymer is still facing challenge. Beta2-microglobulin (ß2m) is a protein biomarker that can be used in diagnosis of different diseases. In this research, a novel MIP with ability of ß2m recognition has been developed by epitope and surface-confined imprinting approaches. A peptide with sequence of MIQRTPKIQ was selected as template. A strategy of combination of hierarchical imprinting and template immobilization was employed in the ß2m-MIP synthesis. Imprinted binding sites with open-entrance have been created that have good accessibility for ß2m and facilitated fast reversible binding kinetics. The experimental results demonstrated that the MIP has good selectivity. It can differentiate the template from peptide with different sequence and distinguish the ß2m from other proteins with similar size and pI values. After binding property study of the ß2m-MIP, a method of ß2m determination in serum was established in which ß2m was on-line extracted by MIP and analyzed by HPLC process. The recoveries for spiked serum was ≥83% with RSD <1.1%, indicating that the method has good accuracy and precisions. The LOD and LOQ were 0.058 and 0.195mgL-1 respectively, which meet the requirements of the ß2m analysis. The successful application of the ß2m-MIP demonstrated that ß2m has reversible binding on the MIP with a kinetics that can meet the requirements of the HPLC analysis. It also indicated that the ß2m-MIP has good mechanical strength and reusability that can be applied reliably in the practical analysis. As a synthetic antibody, ß2m-MIP is advantageous compared to the biological molecules.

Isolation of a facultative anaerobic exoelectrogenic strain LZ-1 and probing electron transfer mechanism in situ by linking UV/Vis spectroscopy and electrochemistry.

A new facultative anaerobic exoelectrogenic strain LZ-1, belonging to Citrobacter freundii, has been isolated. This strain can produce current densities of 843.9 and 865.6µAcm-2 using citrate or acetate as carbon source in a three-electrode configuration. The electricity generation performance was also analyzed in a dual-chamber MFC system, reaching a maximum power density of 1233mWm-2. In addition to acetate and citrate, other carbon sources such as pyruvate, formate, acetate, citrate and fumarate could also be utilized to produce current by strain LZ-1. Data supports the presence of electroactive c-type cytochromes in C. freundii sp. when grown on ITO electrodes, by linking spectroscopy and electrochemistry in situ. Since facultative strains possess many desirable properties compared to anaerobic strains, strain LZ-1 represents a promising exoelectrogenic species in engineering of biological catalysts for microbial electrochemistry.

Expression of the moss PpLEA4-20 gene in rice enhances membrane protection and client proteins stability.

Green vegetative tissues of the moss Physcomitrella patens possess a powerful ability to tolerate severe drought stress. Proteomics analysis have revealed that a large number of late embryogenesis abundant (LEA) proteins were key players in the drought tolerance of the photosynthetic tissues. PpLEA4-20, a member of the moss LEA protein family, was selected for further function study using an ectopic expression method in rice. Through molecular identification via PCR, southern blotting and TAIL-PCR, we demonstrated that the PpLEA4-20 gene was transformed and inserted into a non-encoded region in chromosome 4 of rice and expressed stably in transgenic rice. Unexpectedly, PpLEA4-20 protein emerged as two high-expressed spots on 2-D gels generated from transgenic rice, suggesting that PpLEA4-20 proteins are complete compatible and might be modified in rice. Both growth and physiological analysis showed that seedlings of transgenic PpLEA4-20 rice displayed altered phenotypes and tolerance to salt. In addition, electrolyte leakage was reduced in transgenic PpLEA4-20 compared to wild type under stress conditions. Anti-aggregation analysis found that the PpLEA4-20 protein expressed in rice remained soluble at high temperature and in addition to some native proteins from transgenic PpLEA4-20 rice. Based on Nano LC MS/MS analysis, we identified several proteins from transgenic PpLEA4-20 rice of increased heat-stability. Our results provide evidence for a role of PpLEA4-20 in salt tolerance and stabilization of client proteins.

Direct detection of rutin-degrading isozymes with polyacrylamide gel electrophoresis.

Rutin-degrading enzymes (RDEs) specifically hydrolyze the glycosidic linkages of rutin, producing quercetin and rutinose. Here we report a reliable and sensitive polyacrylamide gel electrophoresis and staining method for the detection of RDE isozymes, which is based on the aqueous solubility difference between rutin and quercetin, as well as the ultraviolet absorbance of quercetin. With this novel method, we achieved a detection limit of 12 ng with 107 U of RDE activity, enabling us to detect at least five RDE isozymes in tartary buckwheat seeds.