Hypoxic niches attract and sequester tumor-associated macrophages and cytotoxic T cells and reprogram them for immunosuppression.

Glioblastoma (GBM), a highly lethal brain cancer, is notorious for immunosuppression, but the mechanisms remain unclear. Here, we documented a temporospatial patterning of tumor-associated myeloid cells (TAMs) corresponding to vascular changes during GBM progression. As tumor vessels transitioned from the initial dense regular network to later scant and engorged vasculature, TAMs shifted away from perivascular regions and trafficked to vascular-poor areas. This process was heavily influenced by the immunocompetence state of the host. Utilizing a sensitive fluorescent UnaG reporter to track tumor hypoxia, coupled with single-cell transcriptomics, we revealed that hypoxic niches attracted and sequestered TAMs and cytotoxic T lymphocytes (CTLs), where they were reprogrammed toward an immunosuppressive state. Mechanistically, we identified chemokine CCL8 and cytokine IL-1ß as two hypoxic-niche factors critical for TAM trafficking and co-evolution of hypoxic zones into pseudopalisading patterns. Therefore, perturbation of TAM patterning in hypoxic zones may improve tumor control.

Macrophages facilitate peripheral nerve regeneration by organizing regeneration tracks through Plexin-B2.

The regeneration of peripheral nerves is guided by regeneration tracks formed through an interplay of many cell types, but the underlying signaling pathways remain unclear. Here, we demonstrate that macrophages are mobilized ahead of Schwann cells in the nerve bridge after transection injury to participate in building regeneration tracks. This requires the function of guidance receptor Plexin-B2, which is robustly up-regulated in infiltrating macrophages in injured nerves. Conditional deletion of Plexin-B2 in myeloid lineage resulted in not only macrophage misalignment but also matrix disarray and Schwann cell disorganization, leading to misguided axons and delayed functional recovery. Plexin-B2 is not required for macrophage recruitment or activation but enables macrophages to steer clear of colliding axons, in particular the growth cones at the tip of regenerating axons, leading to parallel alignment postcollision. Together, our studies unveil a novel reparative function of macrophages and the importance of Plexin-B2-mediated collision-dependent contact avoidance between macrophages and regenerating axons in forming regeneration tracks during peripheral nerve regeneration.

Alveolar Macrophages-Mediated Translocation of Intratracheally Delivered Perfluorocarbon Nanoparticles to Achieve Lung Cancer 19F-MR Imaging.

Recent advances in intratracheal delivery strategies have sparked considerable biomedical interest in developing this promising approach for lung cancer diagnosis and treatment. However, there are very few relevant studies on the behavior and mechanism of imaging nanoparticles (NPs) after intratracheal delivery. Here, we found that nanosized perfluoro-15-crown-5-ether (PFCE NPs, ∼200 nm) exhibite significant 19F-MRI signal-to-noise ratio (SNR) enhancement than perfluorooctyl bromide (PFOB NPs) up to day 7 after intratracheal delivery. Alveolar macrophages (AMs) engulf PFCE NPs, become PFCE NPs-laden AMs, and then migrate into the tumor margin, resulting in increased tumor PFCE concentration and 19F-MRI signals. AMs-mediated translocation of PFCE NPs to lung draning lymph nodes (dLNs) decreases the background PFCE concentration. Our results shed light on the dynamic AMs-mediated translocation of intratracheally delivered PFC NPs for effective lung tumor visualization and reveal a pathway to develop and promote the clinical translation of an intratracheal delivery-based imaging strategy.

[Genetic analysis of a Chinese pedigree with an allele dropout at the HLA-B locus].

OBJECTIVE: To delineate a deletional mutation of the HLA-B gene in a Chinese pedigree. METHODS: A female patient with acute myeloid leukemia who had visited Liuzhou People's Hospital in April 2022 was selected as the study subject. Routine human leukocyte antigen (HLA) was determined by using PCR-sequence specific oligonucleotide polymorphism (PCR-SSOP) and PCR-sequence-based typing (PCR-SBT) methods. Next generation sequencing (NGS) was used to validate the candidate variant in the HLA-B gene. RESULTS: The PCR-SBT and SSOP results for the HLA-B locus were inconsistent for the patient and her daughter. The SSOP results of the two individuals were HLA-B*35:01, 40:02 and HLA-B*35:01, 40:01, respectively. However, the PCR-SBT results has indicated a mismatch with the nearest HLA-B*35:01 at exon 4. NGS results showed that the HLA-B*35:01 had a 9 bp deletion in the intron 5. The patient's husband was HLA-B*40:01, 58:01, which was normal. CONCLUSION: The variant in intron 5 of the HLA-B gene in this pedigree has mapped to a primer-binding region for the SBT reagent, which has affected the accuracy of PCR-SBT results.

Pulmonary Delivery of Theranostic Nanoclusters for Lung Cancer Ferroptosis with Enhanced Chemodynamic/Radiation Synergistic Therapy.

Inefficient tumor accumulation and penetration remain as the main challenges to therapy efficacy of lung cancer. Local delivery of smart nanoclusters can increase drug penetration and provide superior antitumor effects than systemic routes. Here, we report self-assembled pH-sensitive superparamagnetic iron oxide nanoclusters (SPIONCs) that enhance in situ ferroptosis and apoptosis with radiotherapy and chemodynamic therapy. After pulmonary delivery in orthotopic lung cancer, SPIONCs disintegrate into smaller nanoparticles and release more iron ions in an acidic microenvironment. Under single-dose X-ray irradiation, endogenous superoxide dismutase converts superoxide radicals produced by mitochondria to hydrogen peroxide, which in turn generates hydroxyl radicals by the Fenton reaction from iron ions accumulated inside the tumor. Finally, irradiation and iron ions enhance tumor lipid peroxidation and induce cell apoptosis and ferroptosis. Thus, rationally designed pulmonary delivered nanoclusters provide a promising strategy for noninvasive imaging of lung cancer and synergistic therapy.

Adaptive Admixture of HLA Class I Allotypes Enhanced Genetically Determined Strength of Natural Killer Cells in East Asians.

Human natural killer (NK) cells are essential for controlling infection, cancer, and fetal development. NK cell functions are modulated by interactions between polymorphic inhibitory killer cell immunoglobulin-like receptors (KIR) and polymorphic HLA-A, -B, and -C ligands expressed on tissue cells. All HLA-C alleles encode a KIR ligand and contribute to reproduction and immunity. In contrast, only some HLA-A and -B alleles encode KIR ligands and they focus on immunity. By high-resolution analysis of KIR and HLA-A, -B, and -C genes, we show that the Chinese Southern Han (CHS) are significantly enriched for interactions between inhibitory KIR and HLA-A and -B. This enrichment has had substantial input through population admixture with neighboring populations, who contributed HLA class I haplotypes expressing the KIR ligands B*46:01 and B*58:01, which subsequently rose to high frequency by natural selection. Consequently, over 80% of Southern Han HLA haplotypes encode more than one KIR ligand. Complementing the high number of KIR ligands, the CHS KIR locus combines a high frequency of genes expressing potent inhibitory KIR, with a low frequency of those expressing activating KIR. The Southern Han centromeric KIR region encodes strong, conserved, inhibitory HLA-C-specific receptors, and the telomeric region provides a high number and diversity of inhibitory HLA-A and -B-specific receptors. In all these characteristics, the CHS represent other East Asians, whose NK cell repertoires are thus enhanced in quantity, diversity, and effector strength, likely augmenting resistance to endemic viral infections.

Self-Targeting Carbon Quantum Dots for Peroxynitrite Detection and Imaging in Live Cells.

Peroxynitrite (ONOO-), a highly reactive nitrogen species (RNS) generated mainly in mitochondria, has been identified to be associated with numerous pathophysiological processes, and thus accurate ONOO- imaging with superior sensitivity and selectivity is highly desirable. Herein, we prepared a new type of carbon quantum dots (CQDs) with mitochondria-targeting function without the aid of any targeting molecules via a simple one-step hydrothermal route. The as-prepared CQDs not only displayed relatively uniform size distribution, few surface defects, high photostability, and excellent biocompatibility but also exhibited good selective fluorescence turn-off response toward ONOO-, owing to the oxidation of amino groups on the surface of carbon dots. A great linear correlation between the quenching efficiency and ONOO- concentration in the range from 0.15 to 1.0 µM with a detection limit of 38.9 nM is shown. Moreover, the as-prepared CQDs acting as a functional optical probe through a self-targeting mechanism were successfully applied for in situ visualization of endogenous ONOO- generated in the mitochondria of live cells, providing great promise for elucidating the complex biological roles of ONOO- in related pathological processes.

Inhibition of lncRNA DCST1-AS1 suppresses proliferation, migration and invasion of cervical cancer cells by increasing miR-874-3p expression.

BACKGROUND: Cervical cancer seriously threatens both the health and life of women. We aimed to investigate whether RNA interference of long non-coding RNA (lncRNA) DCST1-AS1 could promote miR-874-3p expression to affect the proliferation, migration and invasion of cervical cancer cells. METHODS: DCST1-AS1 expression levels in cervical cancer cells and transfection effects were detected by quantitative reverse transcriptase-polymerase chain reaction analysis. Proliferation, invasion and migration of cells were separately shown by cell-counting kit-8, wound healing and transwell assays, and relative protein expression was determined by western blot analysis. Dual-luciferase reporter and RNA immunoprecipitation assays verified the interaction of DCST1-AS1 and miR-874-3p. RESULTS: DCST1-AS1 expression was increased in cervical cancer tissues and cells. The DCST1-AS1 expression in Hela and SiHa cells was the highest, and so the cells were selected for the next experiment. Inhibition of DCST1-AS1 suppressed the proliferation, invasion and migration of cervical cancer cells and decreased the expression of KI67, proliferating cell nuclear antigen, matrix metalloproteinase (MMP)-2 and MMP-9. miR-874-3p expression was increased when cells were transfected with miR-874-3p mimic or shRNA-DCST1-AS1-1, and DCST1-AS1 expression was down-regulated when cells were transfected with miR-874-3p mimic. DCST1-AS1 can directly target miR-874-3p. Furthermore, inhibition of miR-874-3p could effectively alleviate the effect of inhibition of DCST1-AS1 with respect to the proliferation, invasion and migration of cervical cancer cells. CONCLUSIONS: Inhibition of DCST1-AS1 suppressed the proliferation, migration and invasion of cervical cancer cells by increasing miR-874-3p expression, which could be alleviated by the inhibition of miR-874-3p.

[Identification of a novel HLA-DQB1*03 allele caused by variant of a single nucleotide].

OBJECTIVE: To delineate the characteristics of a novel HLA-DQB1 allele identified during routine HLA matching in a leukemia family. METHODS: The mother and brother of the patient were subjected to PCR sequence-specific oligonucleotide probe (SSOP), PCR sequence-based typ1ing (SBT), as well as next-generation sequencing (NGS). RESULTS: PCR-SBT revealed that the patient's mother and brother's HLA-DQB1 sequences did not fully match with any known allele combination. NGS revealed that the novel allele has differed from the closest matched DQB1*03:02 with a T>G substitution at position 233 in exon 2, which resulted in substitution of Valine at codon 46 by Glycine. Pedigree analysis confirmed that the novel HLA-DQB1 allele was inherited from his mother. CONCLUSION: A novel HLA-DQB1 allele has been identified through next generation sequencing and was officially named as HLA-DQB1*03:362 by the World Health Organization HLA Factor Nomenclature Committee.

[Analysis and verification of a HLA-DQB1*03:90N allele with a single base deletion].

OBJECTIVE: To verify a HLA-DQB1*03:90N allele and method to improve the accuracy of HLA typing. METHODS: A total of 2265 hematopoietic stem cell donors from Shenzhen Branch of China Marrow Donor Program in 2018 were initially detected by a PCR sequence-specific oligonucleotide probe (SSOP) method. Among these, a rare HLA-DQB1 allele was identified by sequence-based tying (SBT) and Ion Torrent S5 next generation sequencing (NGS). RESULTS: The SSOP typing result suggested the HLA-DQB1 to be a rare allele, while an insertion and a deletion was suspected in its exon 2 by SBT, which were confirmed by NGS as DQB1*03:90N and DQB1*06:01, respectively. CONCLUSION: Rare alleles suspected by the SSOP method should be verified by other methods to ensure the accuracy of HLA genotyping. Rare alleles formed by deletions can be detected by NGS with accuracy.

BMP/SMAD Pathway Promotes Neurogenesis of Midbrain Dopaminergic Neurons In Vivo and in Human Induced Pluripotent and Neural Stem Cells.

The embryonic formation of midbrain dopaminergic (mDA) neurons in vivo provides critical guidelines for the in vitro differentiation of mDA neurons from stem cells, which are currently being developed for Parkinson's disease cell replacement therapy. Bone morphogenetic protein (BMP)/SMAD inhibition is routinely used during early steps of stem cell differentiation protocols, including for the generation of mDA neurons. However, the function of the BMP/SMAD pathway for in vivo specification of mammalian mDA neurons is virtually unknown. Here, we report that BMP5/7-deficient mice (Bmp5-/-; Bmp7-/-) lack mDA neurons due to reduced neurogenesis in the mDA progenitor domain. As molecular mechanisms accounting for these alterations in Bmp5-/-; Bmp7-/- mutants, we have identified expression changes of the BMP/SMAD target genes MSX1/2 (msh homeobox 1/2) and SHH (sonic hedgehog). Conditionally inactivating SMAD1 in neural stem cells of mice in vivo (Smad1Nes) hampered the differentiation of progenitor cells into mDA neurons by preventing cell cycle exit, especially of TH+SOX6+ (tyrosine hydroxylase, SRY-box 6) and TH+GIRK2+ (potassium voltage-gated channel subfamily-J member-6) substantia nigra neurons. BMP5/7 robustly increased the in vitro differentiation of human induced pluripotent stem cells and induced neural stem cells to mDA neurons by up to threefold. In conclusion, we have identified BMP/SMAD signaling as a novel critical pathway orchestrating essential steps of mammalian mDA neurogenesis in vivo that balances progenitor proliferation and differentiation. Moreover, we demonstrate the potential of BMPs to improve the generation of stem-cell-derived mDA neurons in vitro, highlighting the importance of sequential BMP/SMAD inhibition and activation in this process.SIGNIFICANCE STATEMENT We identify bone morphogenetic protein (BMP)/SMAD signaling as a novel essential pathway regulating the development of mammalian midbrain dopaminergic (mDA) neurons in vivo and provide insights into the molecular mechanisms of this process. BMP5/7 regulate MSX1/2 (msh homeobox 1/2) and SHH (sonic hedgehog) expression to direct mDA neurogenesis. Moreover, the BMP signaling component SMAD1 controls the differentiation of mDA progenitors, particularly to substantia nigra neurons, by directing their cell cycle exit. Importantly, BMP5/7 increase robustly the differentiation of human induced pluripotent and induced neural stem cells to mDA neurons. BMP/SMAD are routinely inhibited in initial stages of stem cell differentiation protocols currently being developed for Parkinson's disease cell replacement therapies. Therefore, our findings on opposing roles of the BMP/SMAD pathway during in vitro mDA neurogenesis might improve these procedures significantly.

Reconstruction of a skull base defect after endoscopic endonasal resection of a pituitary adenoma: Sphenoid mucosal flaps.

This report describes a bilateral sphenoid sinus mucosal flap for the repair of a sellar floor defect and CSF leak following endoscopic endonasal skull base surgery. The key advantage of this technique is enabling the sphenoid mucosal flaps to remain vascularized, which reduces postoperative complications including CSF leakage, recurrent sinusitis, meningitis, encephalitis and pneumocephalus. The use of this technique is a viable and possibly favorable alternative to free grafts in the reconstruction of small to medium sized sellar defects with low flow or absent CSF leaks base surgery.

Mechanism and Origins of the Chemo- and Regioselectivities in Nickel-Catalyzed Intermolecular Cycloadditions of Benzocyclobutenones with 1,3-Dienes.

The nickel-catalyzed intermolecular cycloadditions of benzocyclobutenones with 1,3-dienes developed by Martin and co-workers are featured with the exclusive proximal C-C bond cleavage and a high chemoselectivity of the [4+4] over the [4+2] cycloaddition. In this report, the detailed reaction mechanism and the origins of the selectivities were investigated by means of density functional theory calculations. The results show that the reaction is initiated by a C-C oxidative addition of the benzocyclobutenone to form the five-membered nickelacycles. A subsequent exo 1,4-insertion/C-C reductive elimination and an endo 1,4-insertion/C-C reductive elimination lead to the [4+4] and [4+2] cycloaddition products, respectively. The 1,4-insertion of the 1,3-diene into the Ni-C bond was calculated to be the rate- and selectivity-determining step of the reaction. The calculations reproduced quite well the experimentally observed exclusive proximal C-C bond cleavage and the high chemoselectivity of the [4+4] over the [4+2] cycloaddition. In particular, it was found that the steric repulsion between the phosphine ligand and the α-substituent of the benzocyclobutenone has a dramatic impact on the 1,4-insertion, which enables the experimentally observed selectivities.

Using Benchmarking To Strengthen the Assessment of Persistence.

Chemical persistence is a key property for assessing chemical risk and chemical hazard. Current methods for evaluating persistence are based on laboratory tests. The relationship between the laboratory based estimates and persistence in the environment is often unclear, in which case the current methods for evaluating persistence can be questioned. Chemical benchmarking opens new possibilities to measure persistence in the field. In this paper we explore how the benchmarking approach can be applied in both the laboratory and the field to deepen our understanding of chemical persistence in the environment and create a firmer scientific basis for laboratory to field extrapolation of persistence test results.

[Association of genetic polymorphisms of KIR-HLA system with chronic myeloid leukemia among ethnic Hans from southern China].

OBJECTIVE: To explore the association of KIR-HLA gene polymorphism with chronic myeloid leukemia (CML) among ethnic Hans from southern China. METHODS: A total of 172 adult CML patients and 480 unrelated healthy controls were screened for the presence of KIR with sequence-specific primers-PCR (PCR-SSP) and sequence-based typing (SBT) of HLA-A, -B and -C loci. Polymorphisms of the KIR-HLA system were analyzed at 4 levels, and the frequencies of KIR framework genes and KIR profiles, classⅠHLA ligands, matched KIR+HLA pairs and KIR-HLA compound profile were compared between the two groups. P values were calculated using SPSS 13.0 software. RESULTS: For the CML group, the frequencies of HLA-C2 ligand, 2DL1+HLA-C2 pair and HLA-B Bw4-80I were significantly lower than those of the control group, suggesting a protective effect against CML (HLA-C2: OR=0.386, 95%CI:0.240-0.620, P<0.01; 2DL1+HLA-C2: OR=0.316, 95%CI:0.191-0.525, P<0.01; HLA-B Bw4-80I: OR=0.576, 95%CI:0.384-0.862, P<0.01). The frequencies of KIR2DL1 ligand (HLA-C2) and KIR3DL1 ligand (HLA-B Bw4-80I) in the CML group were significantly lower than that of the control group, suggesting that the HLA-C2 and HLA-B Bw4-80I expression is probably decreased in the CML patient group, which led to reduced inhibitory signal and enhanced activating signal of KIR2DL1+ and/or KIR3DL1+ NK cells. Notably, the frequency of KIR-HLA compound profiles ID2 (KIR AA1-HLA-C1/C1-Bw6/Bw6-A3/11) in CML patients significantly increased in the CML patient group compared with the control group, suggesting that the KIR-HLA compound profiles ID2 may be a risk factor for CML (OR=2.163, 95%CI 1.198-3.906, P<0.01). CONCLUSION: Above analysis has identified certain protective and risk factors for CML from the KIR-HLA system, which may provide a clue for the pathogenesis of leukemia and development of individualized immune therapy.

[Genetic polymorphisms of KIR2DS4 gene among ethnic Hans from southern China].

OBJECTIVE: To study genetic polymorphisms of the KIR2DS4 gene among ethnic Hans from southern China. METHODS: Genomic DNA was isolated from 306 unrelated individuals and amplified with KIR2DS4-specific PCR primers. KIR2DS4-positive samples were genotyped for the entire coding sequence by sequencing-based typing (SBT). Assignment of allelic genotypes was accomplished by using Assign 3.5 software. For samples with inconclusive SBT results, RT-PCR products covering the entire coding sequence of the KIR2DS4 gene were subjected to cloning and haplotype sequencing. RESULTS: Among all tested samples, 297 were demonstrated to have carried the KIR2DS4 framework gene. For KIR2DS4-positive samples subjected to SBT for the entire coding sequences, no background was observed with the obtained sequences. Three of the seven identified alleles were of novel types, which were officially named by the KIR subcommittee of the World Health Organization Nomenclature Committee for Factors of HLA System. The observed frequencies for the 7 alleles were KIR2DS4*00101 (78.8%), *003 (10.5%), *004 (16.0%), *010 (23.2%), *017 (0.3%), *00105 (0.3%) and *018 (0.7%), respectively. Allele KIR2DS4*007 was not found. The overall frequency for normal cell-surface expression KIR2DS4 alleles including 2DS4*00101, *017 and *00105 was 79.4%, and that for non cell-surface expression alleles including 2DS4*003, *004, *010 and *018 was 50.4%. The ratio between the two was 1.6:1. CONCLUSION: The present study has elucidated the allelic diversity of KIR2DS4 among ethnic Hans from southern China, which may provide valuable data for transplantation as well as studies on KIR-associated disease and evolution.

[Study of polymorphisms of HLA class â (-A, -B, -C) and class â ¡ (DRB1, DQA1, DQB1, DPA1, DPB1) genes among ethnic Hans from Southern China].

OBJECTIVE: To study the genetic polymorphisms of human leukocyte antigen (HLA)- A, B, C, DRB1, DQA1, DQB1, DPA1and DPB1among ethnic Hans from southern China. METHODS: 481 randomly selected individuals were genotyped using a polymerase chain reaction (PCR) sequence-based typing (SBT) method for the above genes. Their allele frequencies were determined by direct counting. RESULTS: In total, 28 HLA-A, 57 HLA-B, 28 HLA-C, 40 HLA-DRB1, 18 HLA-DQA1, 17 HLA-DQB1, 6 HLA-DPA1and 21 HLA-DPB1alleles were identified. Among these, common alleles (with allelic frequencies > 0.05) included A*1101, A*2402, A*0207, A*3303, A*0201, B*40:01, B*46:01, B*58:01, B*13:01, B*15:02, C*01:02, C*07:02, C*03:04, C*03:02, C*08:01, C*03:03, C*04:01, DRB1*09:01, DRB1*15:01, DRB1*12:02, DRB1*08:03, DRB1*03:01, DRB1*04:05, DRB1*11:01, DQA1*01:02, DQA1*03:02, DQA1*03:03, DQA1*06:01, DQA1*01:03, DQA1*05:05, DQA1*01:04, DQA1*03:01, DQA1*05:01, DQB1*03:01, DQB1*03:03, DQB1*06:01, DQB1*05:02, DQB1*03:02, DQB1*02:01, DQB1*03:02, DQB1*06:02, DPA1*02:02, DPA1*01:03, DPA1*02:01, DPB1*05:01, DPB1*02:01, DPB1*13:01, DPB1*04:01and DPB1*02:02.For each of the locus, the overall frequencies of common alleles were 75.57%, 52.81%, 78.28%, 62.16%, 86.70%, 77.23%, 95.32% and 81.59%, respectively. CONCLUSION: The allelic frequencies of the 8 selected HLA loci among ethnic Hans from southern China may served as a reference for anthropology, legal medicine, transplantation and disease association studies.

Constitutive ERK1/2 activation contributes to production of double minute chromosomes in tumour cells.

Double minute chromosomes (DMs) are extrachromosomal cytogenetic structures found in tumour cells. As hallmarks of gene amplification, DMs often carry oncogenes and drug-resistance genes and play important roles in malignant tumour progression and drug resistance. The mitogen-activated protein kinase (MAPK) signalling pathway is frequently dysregulated in human malignant tumours, which induces genomic instability, but it remains unclear whether a close relationship exists between MAPK signalling and DMs. In the present study, we focused on three major components of MAPK signalling, ERK1/2, JNK1/2/3 and p38, to investigate the relationship between MAPK and DM production in tumour cells. We found that the constitutive phosphorylation of ERK1/2, but not JNK1/2/3 and p38, was closely associated with DMs in tumour cells. Inhibition of ERK1/2 activation in DM-containing and ERK1/2 constitutively phosphorylated tumour cells was able to markedly decrease the number of DMs, as well as the degree of amplification and expression of DM-carried genes. The mechanism was found to be an increasing tendency of DM DNA to break, become enveloped into micronuclei (MNs) and excluded from the tumour cells during the S/G2 phases of the cell cycle, events that accompanied the reversion of malignant behaviour. Our study reveals a linkage between ERK1/2 activation and DM stability in tumour cells.

Rapid screening and identification of lycodine-type alkaloids in Lycopodiaceae and Huperziaceae plants by ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry.

Lycodine-type alkaloids have gained significant interest owing to their unique skeletal characteristics and acetylcholinesterase activity. This study established a rapid and reliable method using ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q/TOF-MS/MS) for comprehensive characterization of lycodine-type alkaloids for the first time. The lycodine-type alkaloids were detected successfully from Lycopodiastrum casuarinoides, Huperzia serrata and Phlegmarirus carinatus in seven plants of the Lycopodiaceae and Huperziaceae families, based on the established characteristic MS fragmentation of five known alkaloids. Furthermore, a total of 13 lycodine-type alkaloids were identified, of which three pairs of isomers were structurally characterized and differentiated. This study further improves mass analysis of lycodine-type alkaloids and demonstrates the superiority of UPLC with a high-resolution mass spectrometer for the rapid and sensitive structural elucidation of other trace active compounds. Copyright © 2016 John Wiley & Sons, Ltd.

Temporal Variation of Chemical Persistence in a Swedish Lake Assessed by Benchmarking.

Chemical benchmarking was used to investigate the temporal variation of the persistence of chemical contaminants in a Swedish lake. The chemicals studied included 12 pharmaceuticals, an artificial sweetener, and an X-ray contrast agent. Measurements were conducted in late spring, late autumn, and winter. The transformation half-life in the lake could be quantified for 7 of the chemicals. It ranged from several days to hundreds of days. For 5 of the chemicals (bezafibrate, climbazole, diclofenac, furosemide, and hydrochlorothiazide), the measured persistence was lower in late spring than in late autumn. This may have been caused by lower temperatures and/or less irradiation during late autumn. The seasonality in chemical persistence contributed to changes in chemical concentrations in the lake during the year. The impact of seasonality of persistence was compared with the impact of other important variables determining concentrations in the lake: chemical inputs and water flow/dilution. The strongest seasonal variability in chemical concentration in lake water was observed for hydrochlorothiazide (over a factor of 10), and this was attributable to the seasonality in its persistence.