Trends in maternal and child health in China and its urban and rural areas from 1991 to 2020: a joinpoint regression model.

The long-term trends in maternal and child health (MCH) in China and the national-level factors that may be associated with these changes have been poorly explored. This study aimed to assess trends in MCH indicators nationally and separately in urban and rural areas and the impact of public policies over a 30‒year period. An ecological study was conducted using data on neonatal mortality rate (NMR), infant mortality rate (IMR), under-five mortality rate (U5MR), and maternal mortality ratio (MMR) nationally and separately in urban and rural areas in China from 1991 to 2020. Joinpoint regression models were used to estimate the annual percentage changes (APC), average annual percentage changes (AAPC) with 95% confidence intervals (CIs), and mortality differences between urban and rural areas. From 1991 to 2020, maternal and child mortalities in China gradually declined (national AAPC [95% CI]: NMRs - 7.7% [- 8.6%, - 6.8%], IMRs - 7.5% [- 8.4%, - 6.6%], U5MRs - 7.5% [- 8.5%, - 6.5%], MMRs - 5.0% [- 5.7%, - 4.4%]). However, the rate of decline nationally in child mortality slowed after 2005, and in maternal mortality after 2013. For all indicators, the decline in mortality was greater in rural areas than in urban areas. The AAPCs in rate differences between rural and urban areas were - 8.5% for NMRs, - 8.6% for IMRs, - 7.7% for U5MRs, and - 9.6% for MMRs. The AAPCs in rate ratios (rural vs. urban) were - 1.2 for NMRs, - 2.1 for IMRs, - 1.7 for U5MRs, and - 1.9 for MMRs. After 2010, urban‒rural disparity in MMR did not diminish and in NMR, IMR, and U5MR, it gradually narrowed but persisted. MCH indicators have declined at the national level as well as separately in urban and rural areas but may have reached a plateau. Urban‒rural disparities in MCH indicators have narrowed but still exist. Regular analyses of temporal trends in MCH are necessary to assess the effectiveness of measures for timely adjustments.

Early-Stage Oligomerization of Prion-like Polypeptides Reveals the Molecular Mechanism of Amyloid-Disrupting Capacity by Proline Residues.

Proline cis/trans isomerization governs protein local conformational changes via its local mechanical rigidity. The amyloid-disrupting capacity of proline is widely acknowledged; however, the molecular mechanism is still not clear. To understand how proline residues in polypeptide chains influence amyloid propensity, we study several truncated sequences of the TDP-43 C-terminal region (287-322) and their triple proline variants (308PPP310). We use coarse-grained molecular simulation to study the time evolution of the process of aggregation in the early stages in an effective high-concentration condition (∼25 mM). This ensures the long time scales for protein association at laboratory concentrations. We use several experimentally determined structure templates as initial structures of monomer conformations. We carry out oligomer size analysis and cluster analysis, along with several structural measures, to characterize the size distributions of oligomers and their morphological/structural properties. We show that average oligomer size is not a good indicator of amyloid propensity. Structural order and/or morphological properties are better alternatives. We show that proline variants can efficiently maintain the formation of large "ordered" oligomers of shorter truncated sequences, i.e., 307-322. This "order" maintenance is weakened when using longer truncated sequences (i.e., 287-322), leading to the formation of "disordered" oligomers. From an energy trade-off perspective, if the entropic effect is weak (short sequence length), the shape-complementarity of proline variants effectively guides the oligomerization process to form "ordered" oligomer intermediates. This leads to a distinct aggregation pathway that promotes amyloid formation (on-pathway). Strong entropic effects (long sequence length), however, would cause the formation of "disordered" oligomers. This in turn will suppress amyloid formation (off-pathway). The proline shape-complementary effects provide a guided morphological restraint to facilitate the pathways of amyloid formation. Our study supports the importance of structure-based kinetic heterogeneity of prion-like sequence fragments in driving different aggregation pathways. This work sheds light on the role of morphological and structural order of early-stage oligomeric species in regulating amyloid-disrupting capacity by prolines.

Corrigendum: Fibril Surface-Dependent Amyloid Precursors Revealed by Coarse-Grained Molecular Dynamics Simulation.

[This corrects the article DOI: 10.3389/fmolb.2021.719320.].

First Report of Neofusicoccum parvum Causing Leaf Spot on coral trees (Viburnum odoratissimum) in China.

Coral trees (Viburnum odoratissimum), as a class of evergreen shrubs, are mainly planted in landscapes in numerous cities in China. During September 2020, the author investigated four major parks in Hefei (Bao Park, Hefei Botanical Garden, Luzhou Park and Peninsula Park) and the campus of Anhui Agricultural University (approximately 0.5 ha) (31°49'21.30″N, 117°13'18.25″E). The results showed that the incidence rate of leaf spot disease reached 60% among approximately 100,000 coral trees planted in these areas. Coral trees begin to show leaf spots in August. In early stages of coral trees infection, the symptoms appeared as small brown spots ranged in length from 2 to 3 millimeters on the leaves. After the disease patches expand and darken, the coral leaves eventually wither and fall, which seriously affects its viewing and admiring value. To identify the fungal pathogen, the five-point sampling method was used to take typical similar leaf samples from 5 regions, and 6 samples were taken from each site, so a total of 150 samples were obtained. Fragments of sample leaves were surface-sterilized with 1% NaClO, plated on potato dextrose agar, and incubated at 25 °C in the dark. A total of 275 strains were obtained from 150 samples. According to the morphological characteristics, 275 strains were purified and divided into four types. Four representative strains (MI1, K1, F1, D1) were selected from four types for further pathogenicity testing and identification. The pathogenicity test was conducted in triplicate by inoculating wounded leaves of 1-year-old potted V. odoratissimum with 20µL of a conidial suspension (106 conidia/mL). The control was inoculated with sterile water. The specimens were placed in a growth chamber while maintaining 90% relative humidity and 28℃. After five days, the characteristic lesions were observed only on inoculated MI1 spore suspension leaves. The same fungus was reisolated from the lesions, thus fulfilling Koch's postulates. The pathogenic fungi accounted for 60% of all strains. Fungal colonies were circular and had abundant white aerial mycelium, and colonies changed from white to pure black after maturity. Conidia were fusiform (16-17×5-6 µm), thin-walled, transparent, and without diaphragms. Molecular identification was performed by partially sequencing the internal transcribed spacer (ITS) gene, the translation elongation Factor 1-alpha(EF1-alpha) gene, and the ß-tubulin (TUB2) gene by using the primers ITS1/ITS4 (White et al. 1990), EF1-728F (Alves et al. 2008)/EF1-986R (Carbone & Kohn 1999), and Bt2a/Bt2b (Glass & Donaldson 1995), respectively. The obtained ITS sequence (MW767713) showed 99% identity with N. parvum CMW28429 (KU997429.1), the EF1-alpha sequence (MZ398261) showed 99% identity with N. parvum isolate A4 (FJ528597.1), and the TUB2 sequence (MZ398260) showed 99% identity with N. parvum isolate BO52 (KU554657.1). By combining the sequences of individual fragments of each fungus in the order ITS, EF1-alpha and TUB2, MEGA 6.0 was used to analyze the sequence of kinship by using the maximum likelihood method, and the repeat value of bootstraps was 1000. A polygenic phylogenetic tree analysis based on multilocus alignment (ITS, EF1-alpha and TUB2) was constructed with some strains of Botryosphaeriaceae species. The results of the phylogenetic tree showed that MI1 and N. parvum clustered into a branch. To our knowledge, this is the first report of N. parvum causing leaf spot on V. odoratissimum in China.

Fibril Surface-Dependent Amyloid Precursors Revealed by Coarse-Grained Molecular Dynamics Simulation.

Amyloid peptides are known to self-assemble into larger aggregates that are linked to the pathogenesis of many neurodegenerative disorders. In contrast to primary nucleation, recent experimental and theoretical studies have shown that many toxic oligomeric species are generated through secondary processes on a pre-existing fibrillar surface. Nucleation, for example, can also occur along the surface of a pre-existing fibril-secondary nucleation-as opposed to the primary one. However, explicit pathways are still not clear. In this study, we use molecular dynamics simulation to explore the free energy landscape of a free Abeta monomer binding to an existing fibrillar surface. We specifically look into several potential Abeta structural precursors that might precede some secondary events, including elongation and secondary nucleation. We find that the overall process of surface-dependent events can be described at least by the following three stages: 1. Free diffusion 2. Downhill guiding 3. Dock and lock. And we show that the outcome of adding a new monomer onto a pre-existing fibril is pathway-dependent, which leads to different secondary processes. To understand structural details, we have identified several monomeric amyloid precursors over the fibrillar surfaces and characterize their heterogeneity using a probability contact map analysis. Using the frustration analysis (a bioinformatics tool), we show that surface heterogeneity correlates with the energy frustration of specific local residues that form binding sites on the fibrillar structure. We further investigate the helical twisting of protofilaments of different sizes and observe a length dependence on the filament twisting. This work presents a comprehensive survey over the properties of fibril growth using a combination of several openMM-based platforms, including the GPU-enabled openAWSEM package for coarse-grained modeling, MDTraj for trajectory analysis, and pyEMMA for free energy calculation. This combined approach makes long-timescale simulation for aggregation systems as well as all-in-one analysis feasible. We show that this protocol allows us to explore fibril stability, surface binding affinity/heterogeneity, as well as fibrillar twisting. All these properties are important for understanding the molecular mechanism of surface-catalyzed secondary processes of fibril growth.

Pantoea hericii sp. nov., Isolated from the Fruiting Bodies of Hericium erinaceus.

Three Gram-negative, facultatively anaerobic bacterial isolates were obtained from the fruiting bodies of the edible mushroom Hericium erinaceus showing symptoms of soft rot disease in Beijing, China. Sequences of partial 16S rRNA gene placed these isolates in the genus Pantoea. Multilocus sequence analysis based on the partial sequences of atpD, gyrB, infB and rpoB revealed P. eucalypti and P. anthophila as their closest phylogenetic relatives and indicated that these isolates constituted a possible novel species. DNA-DNA hybridization studies confirmed the classification of these isolates as a novel species and phenotypic tests allowed for differentiation from the closest phylogenetic neighbours. The name Pantoea hericii sp. nov. [Type strain LMG 28847(T) = CGMCC 1.15224(T) = JZB 2120024(T)] is proposed.

Pantoea pleuroti sp. nov., Isolated from the Fruiting Bodies of Pleurotus eryngii.

Four Gram-negative-staining, facultatively anaerobic bacterial isolates were obtained from the fruiting bodies of the edible mushroom Pleurotus eryngii showing symptoms of bacterial blight disease in Beijing, China. Nearly complete 16S rRNA gene sequencing placed these isolates in the genus Pantoea. Multilocus sequence analysis based on the partial sequences of atpD, gyrB, infB and rpoB revealed Pantoea agglomerans as their closest phylogenetic relatives. DNA-DNA hybridization and phenotypic tests confirmed the classification of the new isolates as a novel species. The name Pantoea pleuroti sp. nov. [type strain KCTC 42084(T) = CGMCC 1.12894(T) = JZB 2120015(T)] is proposed.

Development of SCAR markers to determine the mating types of Lepista nuda protoplast monokaryons.

Lepista nuda (Bull. ex Fr.) Cooke belongs to Tricholomataceae and is an edible fungus with both economic and medical value. Mycelia were isolated from the fruiting bodies of L. nuda and were used to prepare the protoplast monokaryons. One hundred and fifteen monokaryons were obtained and their mating types were determined using somatic incompatibility tests. Protoplast monokaryons segregated into either the A1B1 or the A2B2 mating types. Inter-simple sequence repeats and sequence-related amplified polymorphism fingerprinting were used to analyse the mating types of these protoplast monokaryons and 16 sequence-characterised amplified region primers were developed to efficiently differentiate between the monokaryon mating types. Multiplex PCR analyses were also established. The data presented here outline a method for the precise and rapid identification of protoplast monokaryon mating types, which has the promise to shorten the period required for conventional crossbreeding.

Facile synthesis of Nafion-stabilized iridium nanoparticles and their direct use for fuel cells and water electrolyzers.

Using a quite small but suitable amount of Nafion as stabilizer, iridium colloids with well controlled particle size were synthesized and directly used for fuel cells or water electrolyzers without further removal or addition of Nafion, meanwhile, a strategy for fabrication of supported catalyst with high utilization was also proposed.