Perfluorooctanoic acid (PFOA) is a persistent contaminant with detrimental effects on the natural environment. This persistence leads to potential enrichment and osmotic transfer, which can affect normal circulation in the environment. PFOA poses significant threats to both the natural environment and human health. Therefore, the development of cost-effective, highly efficient, and environment-friendly PFOA adsorbents is a crucial endeavor. This paper presents the catalyst-free one-pot synthesis of fluorinated nitrogen-rich porous organic polymers (POP-3F) via a Schiff-base condensation reaction. The reaction between the nitrogen-rich compound 1,4-bis(2,4-diamino-1,3,5-triazine)benzene and p-trifluoromethylbenzaldehyde yielded POP-3F. The introduction of fluorine atoms into the nitrogen-rich porous organic polymer enhanced its hydrophobicity, thereby facilitating favorable fluoro-fluorine interactions with PFOA and, thus, improving the efficacy of the adsorbent. Scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), solid-state nuclear magnetic resonance (ssNMR) spectroscopy, X-ray photoelectron spectroscopy (XPS), nitrogen adsorption-desorption analysis, and thermogravimetric analysis (TGA) were used to confirm the successful synthesis and characterization of POP-3F. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was conducted in negative electrospray ionization (ESI) mode coupled with multi-reaction monitoring mode (MRM). The instrument was equipped with an Atlantis T3 column (100 mm×2.1 mm, 3 µm), and analysis was conducted using an external standard method. The influences of various factors on PFOA adsorption by POP-3F, including pH, salt concentration, and humic acid presence, were investigated. The highest PFOA removal rate (98.6%) was achieved at a pH of 2, indicating the applicability of POP-3F for the effective removal of PFOA from acidic industrial wastewater. The removal rate of PFOA was unaffected by increases in NaCl concentration. This phenomenon can be attributed to electrostatic interactions between the protonated secondary amines in POP-3F and deprotonated PFOA. Upon the addition of NaCl, a double electric layer is formed on the POP-3F surface, with Cl- ions in the outer layer and Na+ ions in the inner layer, which weakened these interactions. Humic acid is competitively adsorbed with PFOA. However, POP-3F demonstrated good removal rates even in the presence of high humic acid concentrations in water. Adsorption isotherm and kinetics experiments were conducted at the optimal pH to explore the relevant adsorption mechanism. The results showed a rapid initial adsorption rate, with 95.4% PFOA removal within 5 min. Optimal adsorption equilibrium was achieved within 6 h, and the removal rate decreased by only 0.3% after 24 h. This finding indicates that POP-3F exhibits sustained efficacy for PFOA removal. Langmuir fitting analysis revealed a theoretical maximum adsorption capacity of 191 mg/g for POP-3F; this value surpasses those of activated carbon materials and most other adsorbents, highlighting the superior PFOA-adsorption performance of POP-3F. Additionally, matrix effects minimally affected the removal of PFOA by POP-3F, with only a slight reduction (0.1%) observed in simulated natural water. The recyclability of POP-3F was assessed over five adsorption-desorption cycles. The removal efficenecy exhibited a minor decrease of only 0.67% after five cycles. These results demonstrate the recyclability of the proposed adsorbent, which translates into cost reduction through reusability. This characteristic renders POP-3F a promising candidate for the economical and efficient removal of PFOA from wastewater in practical applications.
Extreme weather poses huge challenges for animals that must adapt to wide variations in environmental temperature and, in many cases, it can lead to the local extirpation of populations or even the extinction of an entire species. Previous studies have found that one element of amphibian adaptation to environmental stress involves changes in mitochondrial gene expression at low temperatures. However, to date, comparative studies of gene expression in organisms living at extreme temperatures have focused mainly on nuclear genes. This study sequenced the complete mitochondrial genomes of five Asian hylid frog species: Dryophytes japonicus, D. immaculata, Hyla annectans, H. chinensis and H. zhaopingensis. It compared the phylogenetic relationships within the Hylidae family and explored the association between mitochondrial gene expression and evolutionary adaptations to cold stress. The present results showed that in D. immaculata, transcript levels of 12 out of 13 mitochondria genes were significantly reduced under cold exposure (p < 0.05); hence, we put forward the conjecture that D. immaculata adapts by entering a hibernation state at low temperature. In H. annectans, the transcripts of 10 genes (ND1, ND2, ND3, ND4, ND4L, ND5, ND6, COX1, COX2 and ATP8) were significantly reduced in response to cold exposure, and five mitochondrial genes in H. chinensis (ND1, ND2, ND3, ND4L and ATP6) also showed significantly reduced expression and transcript levels under cold conditions. By contrast, transcript levels of ND2 and ATP6 in H. zhaopingensis were significantly increased at low temperatures, possibly related to the narrow distribution of this species primarily at low latitudes. Indeed, H. zhaopingensis has little ability to adapt to low temperature (4 °C), or maybe to enter into hibernation, and it shows metabolic disorder in the cold. The present study demonstrates that the regulatory trend of mitochondrial gene expression in amphibians is correlated with their ability to adapt to variable climates in extreme environments. These results can predict which species are more likely to undergo extirpation or extinction with climate change and, thereby, provide new ideas for the study of species extinction in highly variable winter climates.
Anura , Genome, Mitochondrial , Phylogeny , Animals , Anura/genetics , Anura/physiology , Cold-Shock Response/genetics , Cold Temperature , Adaptation, Physiological/genetics , Gene Expression Regulation
Unusual climates can lead to extreme temperatures. Fejervarya kawamurai, one of the most prevalent anurans in the paddy fields of tropical and subtropical regions in Asia, is sensitive to climate change. The present study focuses primarily on a single question: how do the 13 mitochondrial protein-coding genes (PCGs) respond to extreme temperature change compared with 25 °C controls? Thirty-eight genes including an extra tRNA-Met gene were identified and sequenced from the mitochondrial genome of F. kawamurai. Evolutionary relationships were assessed within the Dicroglossidae and showed that Dicroglossinae is monophyletic and F. kawamurai is a sister group to the clade of (F. multistriata + F. limnocharis). Transcript levels of mitochondrial genes in liver were also evaluated to assess responses to 24 h exposure to low (2 °C and 4 °C) or high (40 °C) temperatures. Under 2 °C, seven genes showed significant changes in liver transcript levels, among which transcript levels of ATP8, ND1, ND2, ND3, ND4, and Cytb increased, respectively, and ND5 decreased. However, exposure to 4 °C for 24 h was very different in that the expressions of ten mitochondrial protein-coding genes, except ND1, ND3, and Cytb, were significantly downregulated. Among them, the transcript level of ND5 was most significantly downregulated, decreasing by 0.28-fold. Exposure to a hot environment at 40 °C for 24 h resulted in a marked difference in transcript responses with strong upregulation of eight genes, ranging from a 1.52-fold increase in ND4L to a 2.18-fold rise in Cytb transcript levels, although COI and ND5 were reduced to 0.56 and 0.67, respectively, compared with the controls. Overall, these results suggest that at 4 °C, F. kawamurai appears to have entered a hypometabolic state of hibernation, whereas its mitochondrial oxidative phosphorylation was affected at both 2 °C and 40 °C. The majority of mitochondrial PCGs exhibited substantial changes at all three temperatures, indicating that frogs such as F. kawamurai that inhabit tropical or subtropical regions are susceptible to ambient temperature changes and can quickly employ compensating adjustments to proteins involved in the mitochondrial electron transport chain.
Neurotransmitters (NTs) are essential for intercellular communication and primarily include monoamine, amino acid, and cholinergic NTs. These molecules play important roles in the body's stress response, motor coordination, neuronal communication, and homeostatic functions. Previous studies have shown that abnormal changes in NT levels are associated with various neurological disorders. Therefore, the development of accurate analytical methods for NT detection will enhance the current understanding on complex neuropathophysiology by providing functional knowledge and techniques for early diagnosis, thereby facilitating the development of new therapeutic options for the related diseases. The solid phase microextraction (SPME) technique combines sample preparation, separation, and enrichment in a single step and is minimally invasive, low cost, solvent free, and high throughput. SPME has been successfully applied to the in vivo analysis of target analytes in animal, human, and plant tissues. The coating material plays a significant role in the development of in vivo SPME methods and must meet various analytical requirements, including a suitable geometry for the SPME device, high extraction capacity, excellent selectivity, and wide extraction coverage for the target analytes. Covalent organic frameworks (COFs) are porous crystalline polymers constructed from organic framework units through strong covalent bonds; these materials are characterized with a low density, large specific surface area, permanent porosity, excellent chemical/thermal stability, and easy functionalization.In this study, a sulfonic acid-functionalized COF material (COF-SO3H) with good crystallinity, excellent chemical/thermal stability, strong hydrophobicity, a uniform mesoporous structure, and narrow pore size distribution was prepared using 2,4,6-triformylphloroglucinol and 1,4-diamino-2-nitrobenzene as monomers. Then, the COF-SO3H was coated onto the surface of stainless-steel fibers and used for in vivo enrichment of NTs. The structural properties of COF-SO3H were characterized using various techniques, such as scanning electron microscopy (SEM), Fourier transform-infrared spectroscopy (FT-IR), and X-ray diffraction (XRD), all of which showed that COF-SO3H had a good crystalline structure and uniform mesopore distribution with a specific surface area of 46.17 m2/g. Compared with the SPME fibers of HLB, C18, MCX, amino, and PXC columns, the prepared COF-SO3H fibers showed better extraction efficiency for the target NTs. Next, the factors affecting SPME efficiency were optimized. The optimal desorption solvent was formic acid-methanol-water (0.5â¶49.5â¶50, v/v/v), and the optimal extraction and desorption times were 15 min. A method for the in vivo analysis of NTs in the brains of mice was established by combining the COF-SO3H fibers with ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) under optimal conditions. The NTs were separated on an Acquity UPLC BEH-C18 analytical column (100 mm×2.1 mm, 1.7 µm) with 0.1% formic acid aqueous solution (A) and acetonitrile (B) as the mobile phases. The flow rate was set to 0.2 mL/min, and the gradient elution procedure was as follows: 0-4 min, 5%B-6%B; 4-7 min, 6%B-5%B; 7-11 min, 5%B. Under optimal conditions, the method showed good linearity (r2>0.99). The limits of quantification (S/N≥5) were in the range of 0.003-0.005 µg/mL and 3-5 µg/mL for monoamine and amino acid NTs, respectively, with RSDs of less than 20%. The method showed good precision (0.80%-9.70%) and accuracy (2.08%-17.72%), with absolute matrix effects in the range of 82.22%-117.92%. These values reflect the good purification and enrichment abilities of the proposed fibers for the target analytes. Finally, the established SPME method was combined with UPLC-MS/MS and successfully applied to quantify target NTs in the brains of mice. The proposed strategy provides a practical method for the in vivo detection and quantitative analysis of NTs and expands the applications of functionalized COF materials for the analysis of various targets.
Metal-Organic Frameworks , Humans , Animals , Mice , Chromatography, Liquid , Solid Phase Microextraction , Spectroscopy, Fourier Transform Infrared , Tandem Mass Spectrometry , Amines , Amino Acids , Brain , Neurotransmitter Agents , Solid Phase Extraction , Chromatography, High Pressure Liquid
Storage of volatile active molecules, along with the prolongation of their specific functions, requires the use of regulatable carriers. Pyrazine derivatives are highly volatile compounds with a broad application owing to their flavoring, pharmaceutical, antimicrobial, antiseptic, and insecticidal properties. In this study, pyrazines were stored by coordinating them with cuprous iodide to easily generate a series of luminescent coordination polymer (CP)-based carriers. The CPs could respond to thermal-redox stimuli and manipulate pyrazine release by breaking the labile Cu-N bonds when triggered by the two stimuli. Moreover, the release process could be visualized by decreased luminescence caused by the gradual decomposition of CP structures. The loading efficiencies ranged from 31% to 38%, and the controlled release behaviors accord with the zero-order kinetics. This work is the first to prove that CPs could function as dual stimuli-mediated delivery systems, which hold the potential to control the release and strengthen the usability of functional molecules.
Neurotransmitters (NTs) are basic signaling chemicals used for communication between cells. The most well-known catecholamines (CAs) are epinephrine, norepinephrine, and dopamine. CAs are an important class of monoamine NTs that contain catechins and amine groups. The accurate determination of CAs in biological samples can provide essential information on potential pathogenic mechanisms. However, biological samples generally contain only trace levels of CAs. Therefore, sample pretreatment is necessary to separate and enrich CAs before instrument analysis. Dispersive solid-phase extraction (DSPE) technology combines the principles of liquid-liquid extraction and solid-phase extraction and is a useful method for purifying and enriching the target analytes in complex matrices. This method has the advantages of low solvent consumption, environmental safety, and high sensitivity and efficiency. In addition, the adsorbents used in DSPE do not need to be packed into a column and can simply be completely dispersed in the sample solution; this excellent feature greatly improves the extraction efficiency and simplifies the extraction process. Therefore, the development of new DSPE materials with high efficiency and adsorption capacity using simple preparation procedures has received wide attention from the research community. Carbon nitrides (MXenes) are a class of two-dimensional layered materials that possess good hydrophilicity, a large number of functional groups (-O, -OH, and -F), large layer spacing, different elemental compositions, excellent biocompatibility, and environmental friendliness. However, these materials have a small specific surface area and poor adsorption selectivity, which limits their applications in SPE. The separation selectivity of MXenes can be significantly improved by functional modification. Polyimide (PI) is a crosslinking product that is mainly formed by the condensation polymerization of binary anhydride and diamine. It has a unique crosslinked network structure, as well as a large number of carboxyl groups, and shows excellent characteristics. Therefore, the synthesis of new PI-functionalized Ti3C2Tx (Ti3C2Tx/PI) composites by growing a PI layer on the surface of two-dimensional MXene nanosheets in situ may not only overcome the adsorptive limitations of MXenes but also effectively improve their specific surface area and porous structure, thereby enhancing their mass transfer capacity, adsorption capacity, and selectivity. In this study, a Ti3C2Tx/PI nanocomposite was fabricated and successfully applied as a DSPE sorbent to enrich and concentrate trace CAs in urine samples. The prepared nanocomposite was examined using various characterization methods, including scanning electron microscopy, Fourier transform-infrared spectroscopy, X-ray diffraction, and zeta potential analysis. The effects of the extraction parameters on the extraction efficiency of Ti3C2Tx/PI were also investigated in detail. The adsorption performance of Ti3C2Tx/PI can be described by pseudo-second-order kinetics and the Freundlich isotherm model. The adsorption process appeared to occur on the outer surface, as well as surface voids, of the nanocomposite. The adsorption mechanism of Ti3C2Tx/PI indicated a chemical adsorption process based on multiple electrostatic, π-π, and hydrogen-bonding interactions. The optimal adsorption conditions included an adsorbent dosage of 20 mg, sample pH of 8, adsorption and elution times of 10 and 15 min, respectively, and eluent composed of acetic acid-acetonitrile-water (5â¶47.5â¶47.5, v/v/v). A sensitive method for detecting CAs in urine was subsequently developed by coupling Ti3C2Tx/PI as a DSPE sorbent with HPLC-FLD analysis. The CAs were separated on an Agilent ZORBAX ODS analytical column (250 mm×4.6 mm, 5 µm). Methanol and an aqueous solution of 20 mmol/L acetic acid were used as the mobile phases for isocratic elution. Under optimal conditions, the proposed DSPE-HPLC-FLD method exhibited good linearity in the range of 1-250 ng/mL with correlation coefficients >0.99. The limits of detection (LODs) and limits of quantification (LOQs) were calculated based on signal-to-noise ratios of 3 and 10 and found to be in the range of 0.20-0.32 and 0.7-1.0 ng/mL, respectively. The recoveries of the method were in the range of 82.50%-96.85% with RSDs≤9.96%. Finally, the proposed method was successfully applied to the quantification of CAs in urine samples from smokers and nonsmokers, thereby indicating its applicability for determining trace CAs.
Catecholamines , Titanium , Chromatography, Liquid , Norepinephrine , Acetic Acid
A palladium-catalyzed disilylation reaction applicable for a variety of non-, α-, or ß-substituted and α,ß-disubstituted ortho-halophenylethylenes has been developed. This reaction proceeds with high yields and very low catalyst loadings. The two C-Si bonds of the disilylated products could be well-differentiated chemoselectively in the reaction with various electrophiles.
Achieving the controlled release of functional substances is indispensable in many aspects of life. Especially for the aroma molecules, their effective delivery of flavor and fragrance is challenging. Here, selected pyridines, as highly volatile odorants, were individually coordinated with copper(I) iodide (CuII) via a straightforward one-pot synthesis method, rapidly forming pure or even crystalline CuII cluster-based profragrances at room temperature. The obtained profragrances enabled the stable and high loading of volatile fragrances under ambient conditions and guaranteed their long-lasting release during heating. Furthermore, the intrinsic emission luminescence of these solid-state profragrances decayed along with the aroma release, which can serve as an additional indicator for monitoring the delivery process. This research sets a precedent for using CuII clusters as dual-purpose release agents and greatly expands their potential applications.
The amine submetabolome, including amino acids (AAs) and biogenic amines (BAs), is a class of small molecular compounds exhibiting important physiological activities. Here, a new pyrylium salt named 6,7-dimethoxy-3-methyl isochromenylium tetrafluoroborate ([d0]-DMMIC) with stable isotope-labeled reagents ([d3]-/[d6]-DMMIC) was designed and synthesized for amino compounds. [d0]-/[d3]-/[d6]-DMMIC-derivatized had a charged tag and formed a set of molecular ions with an increase of 3.02 m/z and the characteristic fragment ions of m/z 204.1:207.1:210.1. When DMMIC coupled with liquid chromatography-mass spectrometry (LC-MS), a systematic methodology evaluation for quantitation proved to have good linearity (R2 between 0.9904 and 0.9998), precision (interday: 2.2-21.9%; intraday: 1.0-19.7%), and accuracy (recovery: 71.8-108.8%) through the test AAs. Finally, the methods based on DMMIC and LC-MS demonstrated the advantaged application by the nontargeted screening of BAs in a common medicinal herb Senecio scandens and an analysis of metabolic differences among the amine submetabolomes between the carcinoma and paracarcinoma tissues of esophageal squamous cell carcinoma (ESCC). A total of 20 BA candidates were discovered in S. scandens as well as the finding of 13 amine metabolites might be the highest-potential differential metabolites in ESCC. The results showed the ability of DMMIC coupled with LC-MS to analyze the amine submetabolome in herbs and clinical tissues.
Esophageal Neoplasms , Esophageal Squamous Cell Carcinoma , Humans , Chromatography, Liquid/methods , Tandem Mass Spectrometry/methods , Amino Acids/chemistry , Biogenic Amines , Sodium Chloride , Carbon Isotopes/chemistry
A palladium-catalyzed intermolecular cross-coupling of unreactive C(sp3)-H bonds and azole C(sp2)-H bonds with bromide as a traceless directing group is described. The judicious selection of the bulky and electron-rich phosphine ligand is the key for the success of this cascade process. The protocol features a broad substrate scope, excellent regioselectivity, and good functional group tolerance.
Bromides , Palladium , Azoles , Catalysis , Ligands , Palladium/chemistry
1,4-Palladium migration has emerged as a reliable method for directed C-H functionalization. In contrast to coupling with carbon nucleophiles, limited examples with heteroatom nucleophiles have been reported. Herein we report a palladium-catalyzed intermolecular C(sp3)-H phosphorylation reaction via 1,4-palladium migration, which is often difficult because of the strong coordination of phosphorus reagents to palladium catalysts. Phosphorylation of C(sp3)-H bonds is accomplished in good reaction yields with excellent regioselectivity. The judicious selection of the phosphine ligand proved to be the key to the success of this cascade process.
Carbon , Palladium , Carbon/chemistry , Catalysis , Ligands , Palladium/chemistry , Phosphorylation
Three new recorded species of genus Homidia were collected from Xizang Autonomous Region, China, in the present paper. Among them, a new species, Homidiabreviseta Pan, sp. nov., is included in the present paper. This new species can be identified by having a single uninterrupted dark band on central thoracic segment III; 14 macrochaetae on abdominal segment I and seven on the posterior central abdominal segment IV (half segment); and very short bothriotricha on abdominal segments II-IV. It can be easily discriminated from similar species of Homidia by its colour pattern, chaetotaxy of the labium, and abdominal segments I and IV. The chaetotaxy of the first and second instar larvae of this new species and a key to four species of genus Homidia from Xizang are also provided.
Rana johnsi (Smith 2009) firstly considered as the member of genus Pseudorana, has been moved into the genus Rana. In this study, we sequenced the complete mitochondrial (mt) genome of R. johnsi using the Sanger method. The circular mt genome was 17,873 bp in length and contains 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, two ribosome RNA genes, and one control region. The overall nucleotide composition in majority-strand was 28% A, 29% T, 29% C, and 14% G. We discussed the phylogenetic relationship of R. johnsi in genus Rana using ML and BI analyses based on 13 PCGs. Excluding the clade of subgenus Lithobates, Rana draytonii was the basal clade to all other Rana species, which included R. johnsi as the basal clade. The monophyly of genus Rana was supported, whereas Pseudorana was failed to support.
Endogenous guanidino compounds (GCs), nitrogen-containing metabolites, have very important physiological activities and participate in biochemical processes. Therefore, accurately characterizing the distribution of endogenous GCs and monitoring their concentration variations are of great significance. In this work, a new derivatization reagent, 4,4'-bis[3-(dimethylamino)propyl]benzyl (BDMAPB), with isotope-coded reagents was designed and synthesized for doubly charged labeling of GCs. BDMAPB-derivatized GCs not only promote the MS signal but also form multicharged quasimolecular ions and abundant fragment ions. With this reagent, an isotope-coded doubly charged labeling (ICDCL) strategy was developed for endogenous GCs with high-resolution liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF MS). The core of this methodology is a 4-fold multiplexed set of [d0]-/[d4]-/[d8]-/[d12]-BDMAPB that yields isotope-coded derivatized GCs. Following a methodological assessment, good linear responses in the range of 25 nM to 1 µM with correlation coefficients over 0.99 were achieved. The limit of detection and the limit of quantitation were below 5 and 25 nM, respectively. The intra- and interday precisions were less than 18%, and the accuracy was in the range of 77.3-122.0%. The percentage recovery in tissues was in the range of 85.1-113.7%. The results indicate that the developed method facilitates long-term testing and ensures accuracy and reliability. Finally, the method was applied for the simultaneous analysis of endogenous GCs in four types of lung tissues (solid adenocarcinoma, solid squamous-cell carcinoma, ground-glass carcinoma, and paracancerous tissues) for absolute quantification, nontargeted screening, and metabolic difference analysis. It is strongly believed that ICDCL combined with isotope-coded BDMAPB will benefit the analysis and study of endogenous GCs.
Lung Neoplasms , Humans , Isotopes , Lung , Reproducibility of Results
Telomerase and micro-RNAs (miRNAs) are simultaneously upregulated in a variety of tumor cells and have emerged as promising tumor markers. However, sensitive detection of telomerase and miRNAs in situ remains a great challenge due to their low expression levels. Here, we designed a Boolean logic "AND" signal amplification strategy based on functionalized ordered mesoporous nanoparticles (FOMNs) to achieve ultrasensitive detection of telomerase and miR-21 in living tumor cells. Briefly, the strategy uses telomerase as an input to enable the release of DNA3-ROX-BHQ hairpins by making the wrapping DNA1 form a DNA-a hairpin with the joint participation of dNTPs. Subsequently, DNA2-Ag, DNA3-ROX-BHQ, and the second input miR-21 participated in hybridization chain reaction to amplify fluorescence and Raman signals. Experimental results showed the intensity of output dual signals relevant to the expression levels of telomerase and miR-21. The Ag nanoparticles (AgNPs) not only enhanced the fluorescence signals but also allowed to obtain more sensitive Raman signals. Therefore, even if expression of tumor markers is at a low level, the FOMN-based dual-signal logic operation strategy can still achieve sensitive detection of telomerase and miR-21 in situ. Furthermore, FOMNs can detect miR-21 expression levels in a short time. Consequently, this strategy has a potential clinical application value in detection of tumor markers and the assessment of tumor treatment efficacy.
MicroRNAs/analysis , Nanoparticles/chemistry , Telomerase/analysis , Cell Line , Fluorescence , Humans , Particle Size , Porosity , Surface Properties , Telomerase/metabolism
A nickel-catalyzed asymmetric Suzuki-Miyaura cross-coupling of racemic 3-bromo-phthalides and arylboronic acids was realized for the synthesis of diverse chiral 3-aryl-phthalides in moderate to excellent reaction yields. The reaction proceeded in a stereoconvergent manner and high enantioselectivities were observed for most examined examples. A number of functional groups like aldehyde, ester and bromide were well tolerated. Heteroaromatic boronic acids were also competent coupling partners in this reaction.
A third species of the genus Sinhomidia is described from South China: S. uniseta sp. nov. This new species can be distinguished from the two other species of the genus by the following characters: colour pattern, single labial chaeta M, chaetotaxy on terga and ventral tube, unguis with three inner teeth, and 15 clypeal ciliated chaetae. Also, the chaetotaxy of the first instar of Sinhomidia is described for the first time in the present paper, and confirms the close relationship between Sinhomidia and Homidia. A key to species of Sinhomidia is provided.
Salmonella enterica serovar Typhimurium, a Gram-negative bacterium, can cause infectious diseases ranging from gastroenteritis to systemic dissemination and infection. However, the molecular mechanisms underlying this bacterial dissemination have yet to be elucidated. A study indicated that using the lipopolysaccharide (LPS) core as a ligand, S Typhimurium was able to bind human dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (hCD209a), an HIV receptor that promotes viral dissemination by hijacking antigen-presenting cells (APCs). In this study, we showed that S Typhimurium interacted with CD209s, leading to the invasion of APCs and potentially the dissemination to regional lymph nodes, spleen, and liver in mice. Shielding of the exposed LPS core through the expression of O-antigen reduces dissemination and infection. Thus, we propose that similar to HIV, S Typhimurium may also utilize APCs via interactions with CD209s as a way to disseminate to the lymph nodes, spleen, and liver to initiate host infection.
Cell Adhesion Molecules/physiology , Lectins, C-Type/physiology , Receptors, Cell Surface/physiology , Salmonella typhimurium/pathogenicity , Animals , Antigen-Presenting Cells/microbiology , Female , Host-Pathogen Interactions , Humans , Lipopolysaccharides/physiology , Mannans/pharmacology , Mice , Mice, Inbred C57BL , O Antigens/physiology , Peyer's Patches/physiology , Phagocytosis , RAW 264.7 Cells
Benzo [a]pyrene (BaP) is a model compound for the study of polycyclic aromatic hydrocarbon (PAH) carcinogenesis. Upon metabolism, BaP is metabolized to the ultimate metabolite, BaP trans-7,8-diol-anti-9,10-epoxide (BPDE), that reacts with cellular DNA to form BPDE-dG adducts responsible for BaP-induced mutagenicity, carcinogenicity, and teratogenicity. In this study, we employed our developed LC-MS/MS method to detect and quantity BPDE-dG adducts present in 42 normal human umbilical cord blood samples and 42 birth defect cases. We determined that there is no significant difference in the level of BPDE-dG formation between the normal and birth defect groups. This represents the first time to use an LC-MS/MS method to quantify BPDE-dG in human umbilical blood samples. The results indicated that under experimental conditions, BPDE-dG adducts were detected in all the human umbilical cord blood samples from the normal and birth defect groups.
DNA Adducts/blood , Fetal Blood/chemistry , 7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide/chemistry , Chromatography, Liquid , DNA Adducts/chemistry , Female , Humans , Molecular Conformation , Pregnancy , Tandem Mass Spectrometry
The asymmetric rhodium-catalyzed alkenylation of enones and imines with arylboronic acids has been developed. A highly controllable aryl to vinyl 1,4-rhodium migration is the key step. Stereodefined vinyl moieties were installed in excellent enantioselectivies for most examined examples. DFT calculations reveal that the driving force of this rhodium migration is a kinetically favored process.
