Hippocampal storage and recall of neocortical "What"-"Where" representations.

A key question for understanding the function of the hippocampus in memory is how information is recalled from the hippocampus to the neocortex. This was investigated in a neuronal network model of the hippocampal system in which "What" and "Where" neuronal firing rate vectors were applied to separate neocortical modules, which then activated entorhinal cortex "What" and "Where" modules, then the dentate gyrus, then CA3, then CA1, then the entorhinal cortex, and then the backprojections to the neocortex. A rate model showed that the whole system could be trained to recall "Where" in the neocortex from "What" applied as a retrieval cue to the neocortex, and could in principle be trained up towards the theoretical capacity determined largely by the number of synapses onto any one neuron divided by the sparseness of the representation. The trained synaptic weights were then imported into an integrate-and-fire simulation of the same architecture, which showed that the time from presenting a retrieval cue to a neocortex module to recall the whole memory in the neocortex is approximately 100 ms. This is sufficiently fast for the backprojection synapses to be trained onto the still active neocortical neurons during storage of the episodic memory, and this is needed for recall to operate correctly to the neocortex. These simulations also showed that the long loop neocortex-hippocampus-neocortex that operates continuously in time may contribute to complete recall in the neocortex; but that this positive feedback long loop makes the whole dynamical system inherently liable to a pathological increase in neuronal activity. Important factors that contributed to stability included increased inhibition in CA3 and CA1 to keep the firing rates low; and temporal adaptation of the neuronal firing and of active synapses, which are proposed to make an important contribution to stabilizing runaway excitation in cortical circuits in the brain.

Degradation of UV328 by ozone/peroxymonosulfate system: Performance and mechanisms.

2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol (UV328) is an emerging persistent organic pollutant ubiquitously found in environmental matrices. Though some advanced oxidation processes have been tested to degrade UV328 in waste streams, the degradation mechanisms are largely unknown. In this study, the degradation of UV328 by ozone (O3) and peroxymonosulfate (PMS) was systemically investigated. At neutral pH, 97.0% UV328 was removed in 5 min with 6.4 mg/min O3 and 2 mM PMS, and the degradation rate was positively correlated with the concentration of oxidants. Hydroxyl radical (•OH), sulfate radical (SO4•-) and singlet oxygen (1O2) participated in the degradation of UV328, in which 1O2 played a key role. Based on the identified transformation intermediates and density functional theory simulations, three degradation pathways of dehydrogenation, cycloaddition and hydroxylation were proposed. •OH and SO4•- radicals could attack UV328 through hydrogen atom abstraction channel. 1O2-mediated cycloaddition reaction is favorable, and •OH could react with UV328 via radical adduct formation pathway. Toxicity assessment indicated that O3/PMS treatment mitigated the ecological risks of UV328.

A comparative analysis of sivelestat sodium hydrate and ulinastatin combination therapy in the treatment of sepsis with acute respiratory distress syndrome.

OBJECTIVE: This comparative analysis aimed to investigate the efficacy of Sivelestat Sodium Hydrate (SSH) combined with Ulinastatin (UTI) in the treatment of sepsis with acute respiratory distress syndrome (ARDS). METHODS: A control group and an observation group were formed with eighty-four cases of patients with sepsis with ARDS, with 42 cases in each group. The control group was intravenously injected with UTI based on conventional treatment, and the observation group was injected with SSH based on the control group. Both groups were treated continuously for 7 days, and the treatment outcomes and efficacy of both groups were observed. The Murray Lung Injury Score (MLIS), Sequential Organ Failure Assessment (SOFA), and Acute Physiology and Chronic Health Evaluation II (APACHE II) were compared. Changes in respiratory function, inflammatory factors, and oxidative stress indicators were assessed. The occurrence of adverse drug reactions was recorded. RESULTS: The total effective rate in the observation group (95.24%) was higher than that in the control group (80.95%) (P < 0.05). The mechanical ventilation time, intensive care unit (ICU) hospitalization time, and duration of antimicrobial medication in the observation group were shorter and multiple organ dysfunction syndrome incidence was lower than those in the control group (P < 0.05). The mortality rate of patients in the observation group (35.71%) was lower than that in the control group (52.38%), but there was no statistically significant difference between the two groups (P > 0.05). MLIS, SOFA, and APACHE II scores in the observation group were lower than the control group (P < 0.05). After treatment, respiratory function, inflammation, and oxidative stress were improved in the observation group (P < 0.05). Adverse reactions were not significantly different between the two groups (P > 0.05). CONCLUSION: The combination of SSH plus UTI improves lung injury and pulmonary ventilation function, and reduces inflammation and oxidative stress in patients with sepsis and ARDS.

Dynamic Gain Decomposition Reveals Functional Effects of Dendrites, Ion Channels, and Input Statistics in Population Coding.

Modern, high-density neuronal recordings reveal at ever higher precision how information is represented by neural populations. Still, we lack the tools to understand these processes bottom-up, emerging from the biophysical properties of neurons, synapses, and network structure. The concept of the dynamic gain function, a spectrally resolved approximation of a population's coding capability, has the potential to link cell-level properties to network-level performance. However, the concept is not only useful but also very complex because the dynamic gain's shape is co-determined by axonal and somato-dendritic parameters and the population's operating regime. Previously, this complexity precluded an understanding of any individual parameter's impact. Here, we decomposed the dynamic gain function into three components corresponding to separate signal transformations. This allowed attribution of network-level encoding features to specific cell-level parameters. Applying the method to data from real neurons and biophysically plausible models, we found: (1) The encoding bandwidth of real neurons, approximately 400 Hz, is constrained by the voltage dependence of axonal currents during early action potential initiation. (2) State-of-the-art models only achieve encoding bandwidths around 100 Hz and are limited mainly by subthreshold processes instead. (3) Large dendrites and low-threshold potassium currents modulate the bandwidth by shaping the subthreshold stimulus-to-voltage transformation. Our decomposition provides physiological interpretations when the dynamic gain curve changes, for instance during spectrinopathies and neurodegeneration. By pinpointing shortcomings of current models, it also guides inference of neuron models best suited for large-scale network simulations.

Machine-Learning-Assisted Optimization of a Single-Atom Coordination Environment for Accelerated Fenton Catalysis.

Machine learning (ML) algorithms will be enablers in revolutionizing traditional methods of materials optimization. Here, we broaden the use of ML to assist the construction of Fenton-like single-atom catalysts (SACs) by developing a methodology including model building, training, and prediction. Our approach can efficiently extract synthesis parameters that exert a substantial influence on Fenton activity and accurately predict the phenol degradation rate k of SACs with a mean error of ±0.018 min-1. The extended synthesis window with accelerated learning enables the realization that the heating temperatures during SAC synthesis significantly influence the Fe-N coordination number, which ultimately dictates their performance. Through ML-guided optimization, a highly efficient SAC dominated by Fe-N5 sites with exceptional Fenton activity (k = 0.158 min-1) is identified. Our work provides an example for ML-assisted optimization of single-atom coordination environments and illuminates the feasibility of ML in accelerating the development of high-performance catalysts.

Treadmill Exercise Improves PINK1/Parkin-Mediated Mitophagy Activity Against Alzheimer's Disease Pathologies by Upregulated SIRT1-FOXO1/3 Axis in APP/PS1 Mice.

Although treadmill exercise is effective against Alzheimer's disease (AD), the molecular mechanisms underlying these effects are not fully understood. Recent literature has linked the accumulation of damaged mitochondria and defective mitophagy to AD progression. Here, we determined that abnormally activated PINK1/Parkin pathway-mediated mitophagy plays an important role in AD progression and pathogenesis in 6-month-old APP/PS1 mice. We used the lysosomal inhibitor chloroquine and demonstrated that a 12-week treadmill exercise program improved mitochondrial function, decreased accumulation of ß-amyloid plaques, and ameliorated loss of learning and memory ability by enhancing PINK1/Parkin-mediated mitophagy activity in the hippocampus of APP/PS1 mice. Moreover, using the SIRT1 inhibitor EX527, we found that 12 weeks of treadmill exercise rescued PINK1/Parkin-mediated mitophagy by activating the SIRT1-FOXO1/3 axis in the hippocampus of APP/PS1 mice. These findings reveal that activating PINK1/Parkin-mediated mitophagy is a promising strategy for AD treatment, and that the SIRT1-FOXO1/3 axis is a potential candidate for the development of mitophagy enhancers.

VRPharmer: bringing virtual reality into pharmacophore-based virtual screening with interactive exploration and realistic visualization.

SUMMARY: Current pharmacophore-based virtual screening (VS) software has limited interactive capabilities and less intuitive screening processes. In this study, a novel tool named VRPharmer is proposed to perform the entire VS workflow in VR environments. VRPharmer enables users to interactively perceive computation processes and immersively observe molecular structures. Besides a typical screening mode (OPT mode), VRPharmer provides a unique interactive screening mode (SCORE mode) for freely exploring the optimal binding poses. Pharmacophore models are editable to study the impact of each feature and further refine the screening results. Moreover, molecular rendering algorithms are improved for precise representations. AVAILABILITY AND IMPLEMENTATION: VRPharmer is open-source software under the MIT license. The released version is available at https://github.com/VRPharmer/VRPharmer. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Ultrafast population coding and axo-somatic compartmentalization.

Populations of cortical neurons respond to common input within a millisecond. Morphological features and active ion channel properties were suggested to contribute to this astonishing processing speed. Here we report an exhaustive study of ultrafast population coding for varying axon initial segment (AIS) location, soma size, and axonal current properties. In particular, we studied their impact on two experimentally observed features 1) precise action potential timing, manifested in a wide-bandwidth dynamic gain, and 2) high-frequency boost under slowly fluctuating correlated input. While the density of axonal channels and their distance from the soma had a very small impact on bandwidth, it could be moderately improved by increasing soma size. When the voltage sensitivity of axonal currents was increased we observed ultrafast coding and high-frequency boost. We conclude that these computationally relevant features are strongly dependent on axonal ion channels' voltage sensitivity, but not their number or exact location. We point out that ion channel properties, unlike dendrite size, can undergo rapid physiological modification, suggesting that the temporal accuracy of neuronal population encoding could be dynamically regulated. Our results are in line with recent experimental findings in AIS pathologies and establish a framework to study structure-function relations in AIS molecular design.

Treadmill Exercise Ameliorates Adult Hippocampal Neurogenesis Possibly by Adjusting the APP Proteolytic Pathway in APP/PS1 Transgenic Mice.

Alzheimer's disease (AD) is a neurodegenerative disorder known to cause cognitive impairment among the elderly worldwide. Although physical exercise-induced adult hippocampal neurogenesis (AHN) improves cognition, understanding its underlying molecular mechanisms requires further investigation using AD mouse models. In this present work, we subjected amyloid precursor protein (APP)/PS1 mice to a 12-week aerobic treadmill exercise to investigate AHN and its potential mechanisms. We divided 3-month-old littermates wild-type and APP/PS1 transgenic male mice into four groups, and the exercise groups performed 12-week treadmill exercise. Next, we evaluated the influence of treadmill exercise on learning and memory capacity, AHN, and APP proteolytic pathway-related factors. As per our results, the treadmill exercise was able to improve the hippocampal microenvironment in APP/PS1 mice probably by regulating various neurotrophic factors and secretases resulting in APP cleavage through a non-amyloidogenic pathway, which seems to further promote new cell proliferation, survival, and differentiation, enhancing hippocampal neurogenesis. All of these effects ameliorate learning and memory capacity. This study provides a theoretical and experimental basis for understanding AHN in an AD mouse model, which is beneficial for preventing and treating AD.

Anlotinib combined with gefitinib can significantly improve the proliferation of epidermal growth factor receptor-mutant advanced non-small cell lung cancer in vitro and in vivo.

BACKGROUND: The effect of anlotinib combined with epidermal growth factor receptor TKIs (EGFR-TKIs) in patients with advanced non-small cell lung cancer (NSCLC) with acquired resistance to EGFR-TKIs and the possible molecular mechanisms are still unclear. METHODS: From April 2018 to June 2020, 20 patients with advanced NSCLC who had developed potential acquired drug resistance after receiving gefitinib or icotinib were enrolled. Anlotinib (12 mg orally, once a day) was added to the targeted drug at the original dose. Patients underwent computed tomography every 8 weeks, and the curative effect and related side effects were observed. Furthermore, in vitro experiments were performed to study the effect of anlotinib alone or in combination with gefitinib on the proliferation and clone-forming ability of NSCLC cells (A549 cells: EGFR wild-type; H1975 cells: with L858R and T790M mutations). Immunohistochemistry was used to detect the expression of related proteins (Ki-67, CD31, EGFR, P-EGFR, VEGFR2, and p-VEGFR2). RESULTS: After the administration of anlotinib, 8 patients were in a stable condition and continued to receive treatment, and the best efficacy disease control rate (DCR) was 100%. The median follow-up time was 6.6 months (4.08-8.28 months). The median progression-free survival was 15.7 months (10.19-18.87 months). The levels of the tumor marker (carcinoembryonic antigen) were found to be significantly decreased in seven patients. The main adverse reactions reported after anlotinib administration were hypertension, hand-foot-skin reaction, diarrhea, fatigue, oral ulcers, and anorexia.In the in vitro experiment, anlotinib combined with gefitinib significantly inhibited the proliferation and cloning ability of lung cancer cells. In the nude mouse model, this combination treatment significantly inhibited the growth of lung cancer cells. Immunohistochemical results showed that anlotinib combined with gefitinib significantly inhibited the expression of Ki-67, CD31, EGFR, P-EGFR, VEGFR2, and p-VEGFR2 in tumor tissues. CONCLUSIONS: Anlotinib combined with gefitinib inhibited the proliferation of EGFR-TKI-resistant NSCLC cells in vitro and tumor angiogenesis in vivo. It also significantly improved the treatment efficacy for some patients, delaying disease progression and improving survival, with only mild side effects. This drug combination is therefore a promising treatment for patients with EGFR-TKI-resistant and potentially secondary drug-resistant advanced NSCLC.

Organic/inorganic double solutions for magnesium-air batteries.

In order to limit the anode corrosion and improve the battery activity, magnesium-air batteries with organic/inorganic double solutions (0.5 M Mg(ClO4)2-N,N-dimethylformamide (DMF)/0.6 M NaCl-H2O, 0.5 M Mg(ClO4)2-acetonitrile (AN)/0.6 M NaCl-H2O) were prepared. The discharge performance, discharge morphology, and corrosion performance of magnesium anode were researched. Results obtained show that organic electrolytes separate the anode from the aqueous electrolyte, thus improving the anode utilization rate. Due to the NaCl electrolyte used in the air cathode side, batteries show higher discharge voltages. As an example, a better discharge performance has been observed in Mg(ClO4)2-DMF/NaCl-H2O double electrolytes at 1 mA cm-2 discharge. This is attributed to there being no obvious absorption of corrosion products on the anode surface. The results of the discharge morphology and electrochemical impedance spectroscopy agree well with the discharge performance. The magnesium anode discharge mechanism is different for different solutions.

Carbamate C-N Hydrolase Gene ameH Responsible for the Detoxification Step of Methomyl Degradation in Aminobacter aminovorans Strain MDW-2.

Methomyl {bis[1-methylthioacetaldehyde-O-(N-methylcarbamoyl)oximino]sulfide} is a highly toxic oxime carbamate insecticide. Several methomyl-degrading microorganisms have been reported so far, but the role of specific enzymes and genes in this process is still unexplored. In this study, a protein annotated as a carbamate C-N hydrolase was identified in the methomyl-degrading strain Aminobacter aminovorans MDW-2, and the encoding gene was termed ameH A comparative analysis between the mass fingerprints of AmeH and deduced proteins of the strain MDW-2 genome revealed AmeH to be a key enzyme of the detoxification step of methomyl degradation. The results also demonstrated that AmeH was a functional homodimer with a subunit molecular mass of approximately 34 kDa and shared the highest identity (27%) with the putative formamidase from Schizosaccharomyces pombe ATCC 24843. AmeH displayed maximal enzymatic activity at 50°C and pH 8.5. Km and kcat of AmeH for methomyl were 87.5 µM and 345.2 s-1, respectively, and catalytic efficiency (kcat/Km ) was 3.9 µM-1 s-1 Phylogenetic analysis revealed AmeH to be a member of the FmdA_AmdA superfamily. Additionally, five key amino acid residues (162, 164, 191, 193, and 207) of AmeH were identified by amino acid variations.IMPORTANCE Based on the structural characteristic, carbamate insecticides can be classified into oxime carbamates (methomyl, aldicarb, oxamyl, etc.) and N-methyl carbamates (carbaryl, carbofuran, isoprocarb, etc.). So far, research on the degradation of carbamate pesticides has mainly focused on the detoxification step and hydrolysis of their carbamate bond. Several genes, such as cehA, mcbA, cahA, and mcd, and their encoding enzymes have also been reported to be involved in the detoxification step. However, none of these enzymes can hydrolyze methomyl. In this study, a carbamate C-N hydrolase gene, ameH, responsible for the detoxification step of methomyl in strain MDW-2 was cloned and the key amino acid sites of AmeH were investigated. These findings provide insight into the microbial degradation mechanism of methomyl.

Clinicopathological and prognostic significance of platelet-lymphocyte ratio (PLR) in gastric cancer: an updated meta-analysis.

BACKGROUND: Pre-treatment PLR (platelet-lymphocyte ratio) was reported to be associated with the prognosis in gastric cancer (GC), but the results remain inconclusive. This meta-analysis aimed to investigate the prognostic potential of the pre-treatment PLR in gastric cancer. METHODS: We performed a systematic literature search in PubMed, Embase, and the Cochrane Library to identify eligible publications. The hazard ratio (HR)/odds ratio (OR) and its 95% confidence (CI) of survival outcomes and clinicopathological parameters were calculated. RESULTS: A total of 49 studies (51 cohorts), collecting data from 28,929 GC patients, were included in the final analysis. The pooled results demonstrated that the elevated pre-treatment PLR was significantly associated with poor overall survival (OS) (HR 1.37, 95% CI 1.26-1.49, p < 0.001; I2 = 79.90%, Ph < 0.001) and disease-free survival (DFS) (HR 1.52, 95% CI 1.22-1.90, p < 0.001, I2 = 88.6%, Ph < 0.001). Furthermore, the patients with the elevated PLR had a higher risk of lymph node metastasis (OR = 1.17, 95% CI 1.02-1.33, p = 0.023), serosal invasion (T3+T4) (OR = 1.34, 95% CI 1.10-1.64, p = 0.003), and increased advanced stage (III+IV) (OR = 1.20, 95% CI 1.06-1.37, p = 0.004). CONCLUSIONS: An elevated pre-treatment PLR was a prognostic factor for poor OS and DFS and associated with poor clinicopathological parameters in GC patients.

The Prognostic Significance Of Pretreatment Albumin/alkaline Phosphatase Ratio In Patients With Stage IB-IIA Cervical Cancer.

BACKGROUND: Pretreatment albumin/alkaline phosphatase ratio (AAPR) has been discussed about its prognostic value in several malignancies, whereas its role in cervical cancer remains unclear. In this study, we attempt to explore the prognostic significance of the AAPR in stage IB-IIA cervical cancer patients who underwent a radical hysterectomy. PATIENTS AND METHODS: A total of 230 cervical cancer patients were enrolled in this retrospective study. The threshold value of AAPR was determined by receiver operating characteristic (ROC) curve. Kaplan-Meier survival analysis and multivariate analysis were performed to identify independent prognostic predictors of disease-free survival (DFS) and overall survival (OS). RESULTS: The optimal cut-off value of the preoperative AAPR was 0.68. Patients with AAPR<0.68 showed obviously inferior OS and DFS than those with AAPR>0.68 according to Kaplan-Meier curves (DFS: P = 0.011; OS: P = 0.017). In multivariate analysis, the preoperative AAPR showed to be an independent predictive factor for disease-free survival (DFS: P = 0.015) and overall survival (OS: P = 0.019). Moreover, subgroup analysis revealed that the lower AAPR was correlated with worse prognosis in patients with histologic grade I-II; but in those with histologic grade III, there was no significant difference between the two groups. CONCLUSION: Preoperative AAPR was a potentially valuable prognostic index in stage IB-IIA cervical cancer patients. Further prospective studies are required to validate its prognostic value.

Analysis on genetic diversity of 51 Grape germplasm resources / Análise da diversidade genética da videira 51

ABSTRACT: The objective of this study is to research the genetic diversity of the ' Zuijinxiang ' grape and its mutant breeding F1 plants, we screened the excellent mutant plants with potential breeding value. 50 mutated single plants obtained from 137Cs-γ irradiated 'Zuijinxiang' grape seeds were used as research objects, and SCoT molecular marker technology was used for genetic diversity and variation analysis, and clustering research was carried out. The results showed that: (1) 36 SCoT primers produced abundant polymorphisms, and the amplification results showed obvious bright bands, and the amplification efficiency and polymorphism rate were 100%. (2) A total of 221 bands were amplified by 36 primers, of which 175 were rich in polymorphism, the average polymorphic percentage was 80.3%, and the average genetic similarity coefficient was 0.916. (3) The number of observed alleles (Na) ranged from 4 to 8, with an average of 6.1389; the number of effective alleles (Ne) ranged from 1.2772 to 5.6322 with an average of 3.5968; the desired heterozygosity (He) The range is from 0.2192 to 0.8344, the average is 0.6965; the observed heterozygosity (Ho) ranges from 0.1656 to 0.7808 with an average of 0.3035; the Nei's gene diversity index (H) ranges from 0.2170 to 0.8224 with an average of 0.6863; Shannon-Wiener The index (I) ranges from 0.5186 to 1.8597 with an average of 1.4517. (4) UPGMA clustering of 51 materials showed that the test materials could be divided into three groups when the genetic distance was 0.856. The experiment shows that the genetic diversity of the 'Zuijinxiang' radiation variation germplasm resources is rich. In addition, SCoT molecular marker technology can distinguish the materials with close genetic distance, and can be used for early identification techniques of grape mutant materials. This study provides a theoretical basis for the development of excellent mutant germplasm of 'Zuijinxiang' grapes.

RESUMO: O objetivo deste estudo é investigar a diversidade genética da uva 'Zuijinxiang' e de suas plantas F1 reprodutoras mutantes. Foram selecionadas as melhores plantas mutantes com potencial e valor genético. Utilizaram-se como objeto de pesquisa 50 plantas individuais mutantes obtidas de sementes de uva irradiadas com 137Cs-γ 'Zuijinxiang', e a tecnologia de marcadores moleculares SCoT para análise de diversidade genética e variação, e foi realizada uma pesquisa de agrupamento. Os resultados mostraram que: (1) 36 iniciadores de SCoT produziram polimorfismos abundantes, e os resultados de amplificação mostraram bandas claras óbvias, e a eficiência de amplificação e taxa de polimorfismo foram de 100%. (2) Um total de 221 bandas foi amplificado por 36 iniciadores, dos quais 175 eram ricos em polimorfismo, a porcentagem polimórfica média foi de 80,3% e o coeficiente médio de similaridade genética foi de 0,916. (3) O número de alelos observados (Na) variou de 4 a 8, com uma média de 6,1389; o número de alelos efetivos (Ne) variou de 1,2772 a 5,6322 com uma média de 3,5968; a heterozigosidade desejada (He), o intervalo é de 0,2192 a 0,8344, a média é de 0,6965; a heterozigosidade observada (Ho) varia de 0,1656 a 0,7808 com uma média de 0,3035; o índice de diversidade genética (H) de Nei varia de 0,2170 a 0,8224 com uma média de 0,6863; Shannon-Wiener o índice (I) varia de 0,5186 a 1,8597 com uma média de 1,4517. (4) O agrupamento de 51 materiais da UPGMA mostrou que os materiais de teste poderiam ser divididos em três grupos quando a distância genética era de 0,856. O experimento mostra que a diversidade genética dos recursos de germoplasma de variação de radiação "Zuijinxiang" é rica. Além disso, a tecnologia de marcadores moleculares da SCoT pode distinguir os materiais com uma distância genética próxima, e pode ser usada para técnicas de identificação precoce de materiais mutantes da uva. Este estudo fornece uma base teórica para o desenvolvimento de germoplasma mutante excelente de uvas "Zuijinxiang".

Cloning and expression of the carbaryl hydrolase gene mcbA and the identification of a key amino acid necessary for carbaryl hydrolysis.

Carbamate hydrolase is the initial and key enzyme for degradation of carbamate pesticides. In the present study, we report the isolation of a carbaryl-degrading strain Pseudomonas sp. XWY-1, the cloning of its carbaryl hydrolase gene (mcbA) and the characterization of McbA. Strain XWY-1 was able to utilize carbaryl as a sole carbon source and degrade it using 1-naphthol as an intermediate. Transposon mutagenesis identified a mutant of XWY-1M that was unable to hydrolyze carbaryl. The transposon-disrupted gene mcbA was cloned by self-formed adaptor PCR, then expressed in Escherichia coli BL21(DE3) and purified. McbA was able to hydrolyze carbamate pesticides including carbaryl, isoprocarb, fenobucarb, carbofuran efficiently, while it hydrolyzed aldicarb, and propoxur poorly. The optimal pH of McbA was 7.0 and the optimal temperature was 40°C. The apparent Km and kcat values of McbA for carbaryl were 77.67±12.31µM and 2.12±0.10s-1, respectively. Three amino acid residues (His467, His477 and His504) in the predicted polymerase/histidinol phosphatase-like domain were shown to be closely related to the activity of McbA, with His504 being the most important, as a replacement of His504 led to the complete loss of activity. This is the first study to identify key amino acids in McbA.

Identification of the key amino acid sites of the carbendazim hydrolase (MheI) from a novel carbendazim-degrading strain Mycobacterium sp. SD-4.

A novel carbendazim (methyl-1H-benzimidazol-2-ylcarbamate, or MBC) degrading strain SD-4 was isolated and identified preliminarily as Mycobacterium sp. according to its phenotypic features and phylogenetic analysis. This strain could utilize MBC as the sole carbon and nitrogen sources for growth and degrade 50mgL-1 MBC at the average degradation rate of 0.63mgL-1h-1. Strain SD-4 degraded MBC through the typical pathway, in which MBC was first hydrolyzed by MheI to 2-aminobenzimidazole (2-AB) and then converted to 2-hydroxybenzimidazole (2-HB). The MBC hydrolase encoding gene mheI was cloned from strain SD-4 and successfully expressed in Escherichia coli by codon optimization. The sulfhydryl-blocking assay revealed that the activity of MheI was closely related to cysteine, and the site-directed mutation experiment showed that Cys16 and Cys222 played important roles during the hydrolysis of MBC by MheI. Therefore they affected its activity directly and were defined as the key amino acid sites.

Sphingobacterium chuzhouense sp. nov., isolated from farmland soil.

A novel Gram-staining-negative bacterium, designated DH-5T, was isolated from a farmland soil in Chuzhou, Anhui province, China. Cells of strain DH-5T were aerobic, non-motile, non-spore-forming and rod-shaped. The organism grew at 20-37 °C, pH 6.0-9.0 and with 0-5 % NaCl (w/v). The DNA G+C content was 42.8 mol%. The major fatty acids (>5 %) were iso-C15 : 0, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), iso-C17 : 0 3-OH and C16 : 0. The respiratory quinone was MK-7, and the major polar lipids were phosphatidylethanolamine and phosphoglycolipid. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain DH-5T was a member of the genus Sphingobacterium and shared the highest similarity with Sphingobacterium gobiense H7T (96.0 %), followed by Sphingobacterium arenae H-12T (94.5 %). Strain DH-5T exhibited low DNA-DNA relatedness with S. gobiense H7T (35.1±1.4 %) and S. arenae H-12T (21.4±1.0 %). On the basis of phenotypic, genotypic and phylogenetic evidence, DH-5T is considered to represent a novel species of the genus Sphingobacterium, for which the name Sphingobacterium chuzhouense sp. nov. is proposed. The type strain is DH-5T (=ACCC 19856T=KCTC 42746T).

Luteimonas soli sp. nov., isolated from farmland soil.

A yellow-pigmented bacterial strain, designated Y2T, was isolated from farmland soil in Bengbu, Anhui province, China. Cells of strain Y2T were Gram-stain-negative, strictly aerobic, non-motile and rod-shaped. Strain Y2T grew optimally at pH 7.0, 30 °C and in the presence of 2 % (w/v) NaCl. The DNA G+C content was 68.9 mol%. The major fatty acids (>5 %) were iso-C15 : 0, iso-C17 : 0, summed feature 9 (C16 : 0 10-methyl and/or iso-C17 : 1ω9c), iso-C11 : 0 3-OH and iso-C11 : 0. The major respiratory quinone was ubiquinone-8 (Q-8), and the major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. Phylogenetic analysis of the 16S rRNA gene sequences showed that strain Y2T was most closely related to Luteimonas mephitis B1953/27.1T (99.1 % 16S rRNA gene sequence similarity), followed by Luteimonas lutimaris G3T (98.6 %), Luteimonas abyssi XH031T (96.2 %) and Luteimonas aquatica RIB1-20T (96.0 %). Strain Y2T exhibited low DNA-DNA relatedness with Luteimonas mephitis B1953/27.1T (43.6 ± 0.5 %) and Luteimonas lutimaris G3T (43.9 ± 2.1 %). On the basis of phenotypic, genotypic and phylogenetic evidence, strain Y2T represents a novel species of the genus Luteimonas, for which the name Luteimonas soli sp. nov. is proposed. The type strain is Y2T ( = ACCC 19799T = KCTC 42441T).

Diagnostic tools for evaluating the impact of Focal Axonal Swellings arising in neurodegenerative diseases and/or traumatic brain injury.

BACKGROUND: Focal Axonal Swellings arise in several leading neurodegenerative diseases of the central nervous system and are hallmark features of concussions and traumatic brain injuries. Recent theories mapped how the shape of each swelling affects the propagation of spike trains and consequently the information encoded in them. Spikes can be selectively deleted, have their speed affected, or blocked depending upon the severity of the swelling. NEW METHOD: Our computational toolbox extracts meaningful geometrical parameters from sequential images of injured axon segments. The algorithm provides a principled approach for dealing with imaging distortions caused by experimental artifacts in order to extract the cross-section of an axon by detecting local symmetries, turning points and turning regions. RESULTS: Our characterization of the Focal Axonal Swelling allows for an assessment of its impact on spike propagation, leading to a color coding of the axon that highlights problematic regions for information propagation. COMPARISON WITH EXISTING METHODS: Many theoretical works reported distortions in spike propagation related to axonal enlargements. Such estimates, however, were not incorporated to a toolbox that could classify axonal swellings directly from experimental images. CONCLUSIONS: Our MATLAB toolbox thus highlights potential trouble spots of axonal morphology, and similar to car traffic maps, identify blocked or impaired routes for information flow. This computational framework is a promising starting point for diagnosing and assessing the impact of axonal swellings implicated in concussions, Alzheimer's and Parkinson's disease, Multiple Sclerosis and other neurological pathologies.