Recombinant Full-Length TDP-43 Oligomers Retain Their Ability to Bind RNAs, Are Not Toxic, and Do Not Seed TDP-43 Aggregation in Vitro

TAR DNA-binding protein with 43 kD (TDP-43) is a partially disordered protein that misfolds and accumulates in the brains of patients affected by several neurodegenerative diseases. TDP-43 oligomers have been reported to form due to aberrant misfolding or self-assembly of TDP-43 monomers. However, very little is known about the molecular and structural basis of TDP-43 oligomerization and the toxic properties of TDP-43 oligomers due to several reasons, including the lack of conditions available for isolating native TDP-43 oligomers or producing pure TDP-43 oligomers in sufficient quantities for biophysical, cellular, and in vivo studies. To address these challenges, we developed new protocols to generate different stable forms of unmodified and small-molecule-induced TDP-43 oligomers. Our results showed that co-incubation of TDP-43 with small molecules, such as epigallocatechin gallate (EGCG), dopamine, and 4-hydroxynonenal (4-HNE), increased the production yield of TDP-43 stable oligomers, which could be purified by size-exclusion chromatography. Interestingly, despite significant differences in the morphology and size distribution of the TDP-43 oligomer preparations revealed by transmission electron microscopy (TEM) and dynamic light scattering (DLS), they all retained the ability to bind to nucleotide DNA. Besides, circular dichroism (CD) analysis of these oligomers did not show much difference in the secondary structure composition. Surprisingly, none of these oligomer preparations could seed the aggregation of TDP-43 core peptide 279–360. Finally, we showed that all four types of TDP-43 oligomers exert very mild cytotoxicity to primary neurons. Collectively, our results suggest that functional TDP-43 oligomers can be selectively stabilized by small-molecule compounds. This strategy may offer a new approach to halt TDP-43 aggregation in various proteinopathies

Additional file 2 of Monpa, memory, and change: an ethnobotanical study of plant use in Mêdog County, South-east Tibet, China

Additional file 2. The Tibetan alphabet (Vowels)

Additional file 1 of Monpa, memory, and change: an ethnobotanical study of plant use in Mêdog County, South-east Tibet, China

Additional file 1. The Tibetan alphabet (Consonants)

Blends of Linear and Long-Chain Branched Poly(l‑lactide)s with High Melt Strength and Fast Crystallization Rate

The long-chain branched polylactides (LCB-PLAs) prepared by coupling the hydroxyl-terminated two-arm (linear) and triarm PLA prepolymers of identical arm length with hexamethylenediacianate (HDI) were used to improve the melt rheological and crystallization properties of linear polylactide resin, PLA 4032D from NatureWorks. The blends containing LCB-PLA displayed higher zero shear viscosities, more significant shear shinning, more melt elasticity, and much longer relaxation times together with significant strain hardening in elongational deformation. <i>T</i>_g, <i>T</i>_m and crystallinity (<i>X</i>_c) of linear PLA remained virtually unaffected, but the crystallization rate increased obviously, since the branch points of LCB-PLAs could play a role of nucleating agent. High melt strength, fast crystallization, and favorable miscibility improved the foaming ability of the linear/LCB-PLA blends, substantially

Rheology and Crystallization of Long-Chain Branched Poly(l‑lactide)s with Controlled Branch Length

A series of long-chain branched poly­(l-lactide)­s (LCB-PLAs) with controlled branch length were prepared by a simple and efficient method through a combination of ring-opening polymerization (ROP) of l-lactide and a coupling reaction between the terminal OH groups of the PLA prepolymers and the NCO groups of HDI. The influences of reaction conditions on the synthesis of the LCB-PLAs were investigated, and the structures of the resultant LCB-PLAs were characterized by ¹H NMR spectroscopy and SEC-MALLS. By adjusting the degree of polymerization and the composition of the prepolymers, LCB-PLAs with different branch densities and molecular weights between branch points were obtained. The effect of macromolecular chain branching on the rheology and crystallization of PLA was also investigated. The LCB structure contributed to the enhancement of the zero-shear viscosity, complex viscosity, storage modulus, melt strength, and strain hardening under elongational flow. Thermal behavior indicated that the branch structure resulted in a short nucleation induction period and more rapid crystallization, which can be a guarantee of high-strength foams

Evaluation of short chain chlorinated paraffins in human milk and their intake by infants in Hebei Province, China

Short-chain chlorinated paraffins (SCCPs) have drawn increasing interest worldwide since they were included in the list of controlled persistent organic pollutants in Annex A of the Stockholm Convention in 2017, and the potential health risk they pose to humans must be evaluated. In this study, 86 human milk samples were collected from 55 healthy Chinese mothers living in the Shijiazhuang region of Northern China in 2014–2015. Advanced online gel permeation chromatography–gas-chromatography-coupled mass spectrometry with negative-ion chemical ionisation was used to quantify the SCCPs in the samples. The estimated mean level of SCCPs was 2.51 μg g−1 lipid weight (range 0.21–16.12). The SCCP concentration correlated positively with the mother’s bodyweight at the end of pregnancy (P −1 day−1 at 1 month, 7.1 μg kg−1 day−1 at 3 months, and 2.5 μg kg−1 day−1 at 6 months after birth. This study provides initial data on the levels of SCCPs in human milk in a chlorinated-paraffin-manufacturing area in China, and indicates a high health risk for infants.</p

Data_Sheet_1_Detection of Neutralizing Antibodies to Tembusu Virus: Implications for Infection and Immunity.DOCX

Neutralizing antibodies are the key mediators of protective immune response to flaviviruses after both infection and vaccination. Plaque reduction neutralization test (PRNT) is considered the “gold standard” for measurement of the immunity. To date, little is known regarding neutralizing antibody response to Tembusu virus (TMUV), a novel flavivirus emerging in ducks in 2010. Here, we developed a PRNT for detection of TMUV neutralizing antibodies. Following optimization and validation, the PRNT was applied to test serum samples from different flocks of ducks. Using sera prepared in experimental conditions, the levels of 50% end point titer (neutralizing dose, ND50) generated from positive sera (5,012–79,433) were significantly higher than those from mock-infected sera (10 to 126), indicating that the test can be used in the detection of TMUV-specific neutralizing antibodies. Dose-dependent efficacy test of a cell-derived 180th passage of a plaque-purified virus of the PS TMUV isolate (PS180) in combined with immunization-challenge experiments revealed that ND50 titer of ~1,258 is the minimum capable of providing adequate protection against challenge with virulent TMUV. In the investigation of serum samples collected from three flocks infected by TMUV and four flocks vaccinated with a licensed attenuated vaccine (the 120th passage virus), ND50 titers peaked at 1 week after both disease onset (7,943–125,893) and vaccination (3,612–79,432), and high levels of ND50 titer were detected in sera collected at 15 weeks after disease onset (5,012–63,095) and 17 weeks after vaccination (3,981–25,119). Together these findings demonstrated that spontaneous and experimental infections by TMUV and vaccination with the licensed TMUV attenuated vaccine elicit high, long-lasting neutralizing antibodies. The highest ND50 titer of neutralizing antibodies elicited by PS180 was determined to be 3,162, suggesting that attenuation of TMUV by more passages has a dramatic impact on the neutralizing antibody response of the virus.</p

Cytokine release in 16HBE cells exposed to various concentrations of PM2.5.

<p>16HBE cells were exposed to PM2.5 for 5 hours and 24 hours, whereafter the culture supernatants were collected and assessed for (A) IL-6, (B) IL-8 and (C) TNF-α. The data are mean ± SD of independent experiments (n = 3). (*) indicates significant difference (p < 0.05) when compared to control cells (exposed to 0 μg/cm² PM2.5 over the same period), (**) represents significant difference (p < 0.01) compared to control.</p

Gene Responses in the Central Nervous System of Zebrafish Embryos Exposed to the Neurotoxicant Methyl Mercury

Methyl mercury (MeHg) is a neurotoxicant with adverse effects on the development of the nervous system from fish to man. Despite a detailed understanding of the molecular mechanisms by which MeHg affects cellular homeostasis, it is still not clear how MeHg causes developmental neurotoxicity. We performed here a genome-wide transcriptional analysis of MeHg-exposed zebrafish embryos and combined this with a whole-mount in situ expression analysis of 88 MeHg-affected genes. The majority of the analyzed genes showed tissue- and region-restricted responses in various organs and tissues. The genes were linked to gene ontology terms like oxidative stress, transport and cell protection. Areas even within the central nervous system (CNS) are affected differently resulting in distinct cellular stress responses. Our study revealed an unexpected heterogeneity in gene responses to MeHg exposure in different tissues and neuronal subregions, even though the known molecular action of MeHg would predict a similar burden of exposed cells. The overall structure of the developing brain of MeHg-exposed embryos appeared normal, suggesting that the mechanism leading to differentiation of the CNS is not overtly affected by exposure to MeHg. We propose that MeHg disturbs the function of the CNS by disturbing the cellular homeostasis. As these cellular stress responses comprise genes that are also involved in normal neuronal activity and learning, MeHg may affect the developing CNS in a subtle manner that manifests itself in behavioral deficits

Gene Responses in the Central Nervous System of Zebrafish Embryos Exposed to the Neurotoxicant Methyl Mercury

Methyl mercury (MeHg) is a neurotoxicant with adverse effects on the development of the nervous system from fish to man. Despite a detailed understanding of the molecular mechanisms by which MeHg affects cellular homeostasis, it is still not clear how MeHg causes developmental neurotoxicity. We performed here a genome-wide transcriptional analysis of MeHg-exposed zebrafish embryos and combined this with a whole-mount in situ expression analysis of 88 MeHg-affected genes. The majority of the analyzed genes showed tissue- and region-restricted responses in various organs and tissues. The genes were linked to gene ontology terms like oxidative stress, transport and cell protection. Areas even within the central nervous system (CNS) are affected differently resulting in distinct cellular stress responses. Our study revealed an unexpected heterogeneity in gene responses to MeHg exposure in different tissues and neuronal subregions, even though the known molecular action of MeHg would predict a similar burden of exposed cells. The overall structure of the developing brain of MeHg-exposed embryos appeared normal, suggesting that the mechanism leading to differentiation of the CNS is not overtly affected by exposure to MeHg. We propose that MeHg disturbs the function of the CNS by disturbing the cellular homeostasis. As these cellular stress responses comprise genes that are also involved in normal neuronal activity and learning, MeHg may affect the developing CNS in a subtle manner that manifests itself in behavioral deficits