Golgi export of the Kir2.1 channel is driven by a trafficking signal located within its tertiary structure.

Mechanisms that are responsible for sorting newly synthesized proteins for traffic to the cell surface from the Golgi are poorly understood. Here, we show that the potassium channel Kir2.1, mutations in which are associated with Andersen-Tawil syndrome, is selected as cargo into Golgi export carriers in an unusual signal-dependent manner. Unlike conventional trafficking signals, which are typically comprised of short linear peptide sequences, Golgi exit of Kir2.1 is dictated by residues that are embedded within the confluence of two separate domains. This signal patch forms a recognition site for interaction with the AP1 adaptor complex, thereby marking Kir2.1 for incorporation into clathrin-coated vesicles at the trans-Golgi. The identification of a trafficking signal in the tertiary structure of Kir2.1 reveals a quality control step that couples protein conformation to Golgi export and provides molecular insight into how mutations in Kir2.1 arrest the channels at the Golgi.

C-H Functionalization-Enabled 11-Step Semisynthesis of (-)-Veragranine A and Characterization of Synthetic Analogs in Osteoarthritis-related Pain Treatment.

We report an efficient semisynthesis of the cholestane steroidal alkaloid (-)-veragranine A with a 6/6/6/5/6/6 hexacyclic ring system, eight stereocenters, and a unique C12-C23 linkage. Our synthesis features a Schönecker-Baran C-H oxidation at C12, a Suzuki-Miyaura cross-coupling to form the C12-C23 bond, and a hydrogen atom transfer (HAT)-initiated Minisci C-H cyclization to forge the C20-C22 bond with desired stereochemistry at C20. These enabling transformations significantly enhanced the overall synthetic efficiency and delivered (-)-veragranine A in 11 steps and over 200 mg from cheap and readily available dehydroepiandrosterone. In addition, this approach allowed flexible syntheses of novel synthetic analogs for biological evaluations in sensory neurons in vitro and in an in vivo model of arthritic pain, from which two novel lead compounds were identified for further development.

Assessment of Fetal Exposure and Elimination of Perfluoroalkyl and Polyfluoroalkyl Substances: New Evidence from Paired Serum, Placenta, and Meconium Samples.

Multiple pieces of evidence have shown that prenatal exposure to perfluoroalkyl and polyfluoroalkyl substances (PFASs) is closely related to adverse birth outcomes for infants. However, difficult access to human samples limits our understanding of PFASs transport and metabolism across the human placental barrier, as well as the accurate assessment of fetal PFASs exposure. Herein, we assess fetal exposure to 28 PFASs based on paired serum, placenta, and meconium samples. Overall, 21 PFASs were identified first to be exposed to the fetus prenatally and to be metabolized and excreted by the fetus. In meconium samples, 25 PFASs were detected, with perfluorooctane sulfonate and perfluorohexane sulfonic acid being the dominant congeners, suggesting the metabolism and excretion of PFASs through meconium. Perfluoroalkyl sulfonic acids might be more easily eliminated through the meconium than perfluorinated carboxylic acids. Importantly, based on molecular docking, MRP1, OATP2B1, ASCT1, and P-gp were identified as crucial transporters in the dynamic placental transfer of PFASs between the mother and the fetus. ATSC5p and PubchemFP679 were recognized as critical structural features that affect the metabolism and secretion of PFASs through meconium. With increasing carbon chain length, both the transplacental transfer efficiency and meconium excretion efficiency of PFASs showed a structure-dependent manner. This study reports, for the first time, that meconium, which is a noninvasive and stable biological matrix, can be strong evidence of prenatal PFASs exposure.

A Critical Review on Transplacental Transfer of Per- and Polyfluoroalkyl Substances: Prenatal Exposure Levels, Characteristics, and Mechanisms.

Prenatal exposure to perfluoroalkyl and polyfluoroalkyl substances (PFASs) has aroused public concerns as it can pose multiple health threats to pregnant women and cause adverse birth outcomes for fetuses. In previous studies, the prenatal exposure levels and transplacental transfer efficiencies (TTE) of PFASs have been reported and discussed. Specifically, the binding affinities between PFASs and some transporters were determined, demonstrating that the TTE values of PFASs are highly dependent on their binding behaviors. To summarize primary findings of previous studies and propose potential guidance for future research, this article provides a systematic overview on levels and characteristics of prenatal exposure to PFASs worldwide, summarizes relationships between TTE values and structures of PFASs, and discusses possible transplacental transfer mechanisms, especially for the combination between PFASs and transporters. Given the critical roles of transporters in the transplacental transfer of PFASs, we conducted molecular docking to further clarify the binding behaviors between PFASs and the selected transporters. We proposed that the machine learning can be a superior method to predict and reveal behaviors and mechanisms of the transplacental transfer of PFASs. In total, this is the first review providing a comprehensive overview on the prenatal exposure levels and transplacental transfer mechanisms of PFASs.

Levels, distributions, and sources of legacy and novel per- and perfluoroalkyl substances (PFAS) in the topsoil of Tianjin, China.

Soil is a major sink for per- and perfluoroalkyl substances (PFAS), wherein PFAS may be transferred through the food chain to predators at upper trophic levels, which poses a threat to human health. Herein, the concentrations and distributions of legacy and novel PFAS in topsoil samples from different functional areas in Tianjin were comprehensively investigated. Seventeen PFAS congeners were identified, with concentrations ranging from 0.21 ng/g to 5.35 ng/g, with a mean concentration of 1.25 ng/g. The main PFAS in the topsoil was perfluorooctanoic acid (PFOA). 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA; C8) were the major sources (43.4%), followed by food packaging as well as coating materials (25.5%). In addition, Spearman correlation analysis and the structural equation model showed that population density significantly impacted the PFAS distribution in the topsoil of Tianjin.

One-Carbon Insertion and Polarity Inversion Enabled a Pyrrole Strategy to the Total Syntheses of Pyridine-Containing Lycopodium Alkaloids: Complanadine A and Lycodine.

Complanadine A and lycodine are representative members of the Lycopodium alkaloids with a characteristic pyridine-containing tetracyclic skeleton. Complanadine A has demonstrated promising neurotrophic activity and potential for persistent pain management. Herein we report a pyrrole strategy enabled by one-carbon insertion and polarity inversion for concise total syntheses of complanadine A and lycodine. The use of a pyrrole as the pyridine precursor allowed the rapid construction of their tetracyclic skeleton via a one-pot Staudinger reduction, amine-ketone condensation, and Mannich-type cyclization. The pyrrole group was then converted to the desired pyridine by the Ciamician-Dennstedt rearrangement via a one-carbon insertion process, which also simultaneously introduced a chloride at C3 for the next C-H arylation. Other key steps include a direct anti-Markovnikov hydroazidation, a Mukaiyama-Michael addition, and a Paal-Knorr pyrrole synthesis. Lycodine and complanadine A were prepared in 8 and 11 steps, respectively, from a readily available known compound.

Challenges in the Highly Selective [3 + 1]-Cycloaddition of an Enoldiazoacetamide to Form a Donor-Acceptor Cis-Cyclobutenecarboxamide.

A substituted donor-acceptor cyclobutenecarboxamide is synthesized with modest enantiocontrol through a chiral copper(I) complex catalyzed [3 + 1]-cycloaddition reaction of α-acyl diphenylsulfur ylides with 3-siloxy-2-diazo-3-butenamides. With a methyl substituent on the 4-position of the 3-butenamide, the cis-vicinal-3,4-disubstituted cyclobutenecarboxamide is formed with >20:1 diastereocontrol. Donor-acceptor 3-methyl-2-siloxycyclopropenecarboxamide is rapidly formed from the reactant enoldiazoamide and undergoes catalytic ring opening to give only the Z-γ-substituted metallo-enolcarbene. Elimination from 3-siloxy-2-diazo-3-pentenamide to form the conjugated 3-siloxy-2,4-pentadienamide is competitive but minimized at low temperature.

Physical and Antibacterial Properties of Sodium Alginate-Sodium Carboxymethylcellulose Films Containing Lactococcus lactis.

Edible films have gradually become a research focus for food packaging materials due to a variety of benefits, including environmental friendliness, good barrier properties, and good carrying capacity. In this experimental study, we used sodium alginate as a film-forming substrate, sodium carboxymethylcellulose as a modifier, and glycerol as a plasticizer, then Lactococcus lactis was added to film solutions to form bacteriostatic films via the tape casting method. With the addition of Lactococcus lactis, the films did not significantly change thickness, while the transparency decreased and a significant increase in red and yellow hues was observed. Meanwhile, the dispersion of bacterial cells in film solutions destroyed intermolecular interactions in the solutions during film formation and increased the volume of voids in the Lactococcus lactis-containing films, thereby slightly decreasing the tensile strength of the films, but significantly increasing water vapor permeability. Moreover, the films with added Lactococcus lactis showed significant bacteriostatic activity against Staphylococcus aureus at 4 °C. In a seven-day bacteriostatic test, the films with Lactococcus lactis added at a level of 1.5 g/100 g resulted in a decrease in the viable cell count of Staphylococcus aureus by at least four logarithmic units. This study of Lactococcus lactis-containing films has provided a new method and strategy for antibacterial preservation of foods.

Development of a highly specific HER2 monoclonal antibody for immunohistochemistry using protein microarray chips.

HER2 is an orphan receptor tyrosine kinase of the EGFR families and is considered to be a key tumor driver gene [1]. Breast cancer and gastric cancer with HER2 amplification can be effectively treated by its neutralizing antibody, Herceptin. In clinic, Immunohistochemistry (IHC) was used as the primary screening method to diagnose HER2 amplification [2]. However, recent evidence suggested that the frequently used rabbit HER2 antibody 4B5 cross reacted with another family member HER4 [3]. IHC staining with 4B5 also indicated that there was strong non-specific cytoplasmic and nuclear signals in normal gastric mucosal cells and some gastric cancer samples. Using a protein lysate array which covers 85% of the human proteome, we have confirmed that the 4B5 bound to HER4 and a nuclear protein ZSCAN18 besides HER2. The non-specific binding accounts for the unexpected cytoplasmic and nuclear staining of 4B5 of normal gastric epithelium. Finally, we have developed a novel mouse HER2 monoclonal antibody UMAB36 with similar sensitivity to 4B5 but only reacted to HER2 across the 17,000 proteins on the protein chip. In 129 breast cancer and 158 gastric cancer samples, UMAB36 showed 100% sensitivity and specificity comparing to the HER2 FISH reference results with no unspecific staining in the gastric mucosa layer. Therefore, UMAB36 could provide as an alternative highly specific IHC reagent for testing HER2 amplification in gastric cancer populations.

Effect of Dietary Acidolysis-Oxidized Konjac Glucomannan Supplementation on Serum Immune Parameters and Intestinal Immune-Related Gene Expression of Schizothorax prenanti.

The present study was conducted to investigate the effects of dietary acidolysis-oxidized konjac glucomannan (A-OKGM) (0%, 0.4%, 0.8%, and 1.6%) supplementation on the immunity and expression of immune-related genes in Schizothorax prenanti. After feeding for eight weeks, the serum and guts were used for measurement of biochemical parameters, and immune-related gene expression in the gut were also analyzed by real-time quantitative polymerase chain reaction (RT-qPCR). C-reactive protein and IgM levels were significantly higher in the A-OKGM fed groups than in the control group, regardless of the dosage. The 0.4% and 1.6% A-OKGM groups showed significant up-regulation of tumor necrosis factor α (TNFα) in the anterior gut. The 0.8% and 1.6% A-OKGM groups also showed significantly enhanced TNFα expression in the mid- and distal guts. Interleukin-1ß (IL-1ß) expression in the anterior gut of fish fed with 0.4% and 1.6% A-OKGM diets was significantly enhanced. The 0.8% and 1.6% A-OKGM diets resulted in significantly increased the expression of IL-1ß in the distal gut. Similarly, the interleukin-6 (IL-6) messenger RNA (mRNA) levels in the 0.4% and 1.6% diet groups were significantly higher in the anterior gut. The 0.8% and 1.6% A-OKGM diet groups showed significant induction of IL-6 gene expression in the distal gut. A-OKGM modified from KGM can act as an immunostimulant to enhance the immunity of S. prenanti.

Biomimetic Total Synthesis of (±)-Homodimericin†A.

A biomimetic total synthesis of racemic homodimericin A was achieved in seven steps, including two cascade reactions. Aqueous buffer solutions are found to help both the oxidative dimerization cascade and the intramolecular Diels-Alder cascade. This synthetic sequence validates key steps in the biogenetic proposal of homodimericin A.

Application of Volumetric Modulated Arc Therapy and Simultaneous Integrated Boost Techniques to Prepare "Safe Margin" in the Rabbit VX2 Limb Tumor Model.

BACKGROUND: In this study, we aimed to establish the rabbit VX2 limb tumor model, and then prepare a "necrotic zone" as a safe margin by volumetric modulated arc therapy and simultaneous integrated boost (VMAT-SIB) technique applied in the areas where the tumor is located adjacent to the bone (GTVboost area). MATERIAL AND METHODS: Rabbits in the control group (n=10) were not treated, while those in the test group (n=10) were treated with the SIB schedule delivering a dose of 40Gy, 35Gy, 30Gy, and 25Gy to the GTVboost, GTV (gross tumor volume), CTV (clinical target volume), and PTV (planning target volume) in 10 fractions. Magnetic resonance diffusion-weighted imaging (MRDWI), 3-dimensional power Doppler angiography (3D-PDA), and histological changes were observed after radiotherapy. RESULTS: After radiotherapy, the two groups showed a significant difference in the GTVboost area. In the test group, the tumor necrosis showed a significantly low signal in DWI and high signal in apparent diffusion coefficient (ADC) maps. The 3D-PDA observation showed that tumor vascular structures decreased significantly. Histological analysis demonstrated that a necrotic zone could be generated in the GTVboost area, and microscopic examination observed cell necrosis and fibroplasia. CONCLUSIONS: This studies demonstrated the feasibility of using VMAT-SIB technique in the rabbit VX2 limb tumor model. The formation of a necrotic zone can be effectively defined as safe margin in the GTVboost area. showing potential clinical applicability.

Advances in protein-based microcapsules and their applications: A review.

Due to their excellent emulsification, biocompatibility, and biological activity, proteins are widely used as microcapsule wall materials for encapsulating drugs, natural bioactive substances, essential oils, probiotics, etc. In this review, we summarize the protein-based microcapsules, discussing the types of proteins utilized in microcapsule wall materials, the preparation process, and the main factors that influence their properties. Additionally, we conclude with examples of the vital role of protein-based microcapsules in advancing the food industry from primary processing to deep processing and their potential applications in the biomedical, chemical, and textile industries. However, the low stability and controllability of protein wall materials lead to degraded performance and quality of microcapsules. Protein complexes with polysaccharides or modifications to proteins are often used to improve the thermal instability, pH sensitivity, encapsulation efficiency and antioxidant capacity of microcapsules. In addition, factors such as wall material composition, wall material ratio, the ratio of core to wall material, pH, and preparation method all play critical roles in the preparation and performance of microcapsules. The application area and scope of protein-based microcapsules can be further expanded by optimizing the preparation process and studying the microcapsule release mechanism and control strategy.

N-heterocyclic carbene (NHC)-catalyzed/Lewis acid mediated conjugate umpolung of alkynyl aldehydes for the synthesis of butenolides: a formal [3+2] annulation.

Reverse to success! A new formal [3+2] annulation reaction combining alkynyl aldehydes and ß,γ-unsaturated α-ketoesters has been disclosed by using a NHC-catalyzed/Lewis acid mediated strategy. This cooperative catalysis strategy first allows the "allenolate" intermediate as a nucleophilic synthon at the ß-position to react with activated electrophilic reagents by an addition reaction as the key C-C bond-forming step.

Using protein microarray technology to screen anti-ERCC1 monoclonal antibodies for specificity and applications in pathology.

BACKGROUND: An antibody with cross-reactivity can create unexpected side effects or false diagnostic reports if used for clinical purposes. ERCC1 is being explored as a predictive diagnostic biomarker for cisplatin-based chemotherapy. High ERCC1 expression is linked to drug resistance on cisplatin-based chemotherapy. 8F1 is one of the most commonly used monoclonal antibodies for evaluating ERCC1 expression levels in lung cancer patient tissues, but it has been noted that this antibody cross-reacts with an unknown protein. RESULTS: By using a high density protein microarray chip technology, we discovered that 8F1 not only reacts with its authentic target, ERCC1, but also cross-reacts with an unrelated nuclear membrane protein, PCYT1A. The cross-reactivity is due to a common epitope presented on these two unrelated proteins. Similar to the subcellular localization of ERCC1, IHC tests demonstrated that PCYT1A is localized mainly on nuclear membrane. In this study, we also discovered that the PCYT1A gene expression level is significantly higher than the ERCC1 gene expression level in a certain population of lung cancer patient tissue samples. To develop the best monoclonal antibody for ERCC1 IHC analysis, 18 monoclonal antibodies were generated and 6 of them were screened against our protein microarray chip. Two clones showed high mono-specificity on the protein microarray chip test and both worked for the IHC application. CONCLUSION: In summary, the 8F1 clone is not suitable for ERCC1 IHC assay due to its cross-reactivity with PCYT1A protein. Two newly generated monoclonal antibodies, 4F9 and 2E12, demonstrated ultra-specificity against ERCC1 protein and superior performance for IHC analyses.

A hybrid-strategy-improved butterfly optimization algorithm applied to the node coverage problem of wireless sensor networks.

To increase the node coverage of wireless sensor networks (WSN) more effectively, in this paper, we propose a hybrid-strategy-improved butterfly optimization algorithm (H-BOA). First, we introduce Kent chaotic map to initialize the population to ensure a more uniform search space. Second, a new inertial weight modified from the Sigmoid function is introduced to balance the global and local search capacities. Third, we comprehensively use elite-fusion and elite-oriented local mutation strategies to raise the population diversity. Then, we introduce a perturbation based on the standard normal distribution to reduce the possibility of the algorithm falling into premature. Finally, the simulated annealing process is introduced to evaluate the solution's quality and improve the algorithm's ability, which is helpful to jump out of the local optimal value. Through numerous experiments of the international benchmark functions, the results show the performance of H-BOA has been significantly raised. We apply it to the WSN nodes coverage problem. The results show that H-BOA improves the WSN maximum coverage and it is far more than other optimization algorithms.

Assessment of perfluorohexane sulfonic acid (PFHxS)-related compounds degradation potential: Computational and experimental approaches.

Perfluorohexane sulfonic acid (PFHxS) and PFHxS-related compounds are listed in Annex A of the Stockholm Convention without specific exemptions. Substances that potentially degrade to PFHxS are considered as their related compounds. Unfortunately, the degradation behavior of PFHxS precursors, an important basis for the corresponding chemical regulation, remains unclear. Herein, based on the hypothesis that bond dissociation enthalpy (BDE) is the determining factor for the degradation of PFHxS precursors, the BDE of PFHxS-related precursors to produceC6F13SO2-groups was calculated. In addition, quantitative structure-activity relationship models based on partial least squares, partial least squares discrimination analysis, and support vector machine algorithms were developed to predict the BDE of 48 PFHxS precursors and distinguish the precursors with different degradation potential. Subsequent photodegradation experiments demonstrated that the order of degradation rates was consistent with that predicted by theoretical models. Importantly, perfluorohexanoic acid (PFHxA) and perfluorobutanoic acid, and not PFHxS, were detected as the degradation products of potential PFHxS precursors. Sulfonamides, phenyl unit, and other radicals in the non-nucleus part of PFHxS precursors were identified as the critical molecular segments that affect their degradation potential. Ultimately, by comparing BDE values, it was theoretically speculated that PFHxS related compounds exhibit a greater potential to generate PFHxA than PFHxS. Results in this study indicated for the first time that not all the compounds containing C6F13SO2- groups were guaranteed to degrade into PFHxS under natural conditions.

Manipulating high-temperature superconductivity by oxygen doping in Bi2Sr2CaCu2O8+δ thin flakes.

Harnessing the fascinating properties of correlated oxides requires precise control of their carrier density. Compared to other methods, oxygen doping provides an effective and more direct way to tune the electronic properties of correlated oxides. Although several approaches, such as thermal annealing and oxygen migration, have been introduced to change the oxygen content, a continuous and reversible solution that can be integrated with modern electronic technology is much in demand. Here, we report a novel ionic field-effect transistor using solid Gd-doped CeO2 as the gate dielectric, which shows a remarkable carrier-density-tuning ability via electric-field-controlled oxygen concentration at room temperature. In Bi2Sr2CaCu2O8+δ (Bi-2212) thin flakes, we achieve a reversible superconductor-insulator transition by driving oxygen ions in and out of the samples with electric fields, and map out the phase diagram all the way from the insulating regime to the over-doped superconducting regime by continuously changing the oxygen doping level. Scaling analysis indicates that the reversible superconductor-insulator transition for the Bi-2212 thin flakes follows the theoretical description of a two-dimensional quantum phase transition. Our work provides a route for realizing electric-field control of phase transition in correlated oxides. Moreover, the configuration of this type of transistor makes heterostructure/interface engineering possible, thus having the potential to serve as the next-generation all-solid-state field-effect transistor.

N-heterocyclic carbene-catalyzed cascade epoxide-opening and lactonization reaction for the synthesis of dihydropyrone derivatives.

N-Heterocyclic carbene was employed as an efficient organic catalyst to catalyze a cascade epoxide-opening and lactonization reaction. This organocatalytic process could transform various readily accessible γ-epoxy-α,ß-enals into dihydropyrone derivatives in good to excellent yields.

The occurrence of PFAS in human placenta and their binding abilities to human serum albumin and organic anion transporter 4.

Both legacy and emerging per- and polyfluoroalkyl substances (PFAS) have been found to be threats to human health. In particular, fetuses are sensitive to xenobiotics and the placenta functions as a significant barrier for environmental pollutants. The placental transfer of PFAS is closely related to their interactions with proteins. In this study, 54 human placental samples were collected to investigate the occurrence of legacy and emerging PFAS in human placenta, including perfluorinated carboxylates (PFCAs), perfluorinated sulfonates (PFSAs), chlorinated polyfluoroalkyl ether sulfonic acids (Cl-PFESAs), and fluorotelomer sulfonates (FTSAs). Among the legacy PFAS, perfluorooctanesulfonate (PFOS), perfluorooctanoic acid (PFOA), and perfluorononanoic acid (PFNA) were detected in all samples, with PFOS and PFOA being the two predominant (mean: 0.457 and 0.242 ng/g wet weight, respectively). Among the emerging PFAS, 6:2 Cl-PFESA was detected in all samples with the mean value of 0.104 ng/g wet weight, while the detect frequency (DF) of 8:2 Cl-PFESAs was only 24%. The concentration and DF of the four FTSA congeners were low in the placentas. Molecular docking calculation results showed that the binding affinities of PFAS to the human serum albumin (HSA) were increased with chain length in each category except for the PFCAs, of which the perfluoroundecanoic acid (PFUnDA) was the turning point of binding affinity to HSA. For PFSAs, their binding affinities to organic anion transporter 4 (OAT4) were increased with the chain length except for the sodium perfluoro-1-heptanesulfonate (PFHpS) and sodium perfluoro-1-nonanesulfonate (PFNS). The calculation results demonstrated that the placental transfer of PFAS is closely related to chain length. The findings in the study can help better understand the occurrence of the PFAS in the human placenta and the placental transfer mechanisms of PFAS in human beings.