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Coral bleaching caused by climate change has resulted in large-scale coral reef decline worldwide. However, the knowledge of physiological response mechanisms of scleractinian corals under high-temperature stress is still challenging. Here, untargeted mass spectrometry-based metabolomics combining with Global Natural Product Social Molecular Networking (GNPS) was utilized to investigate the physiological response of the coral species Pavona decussata under thermal stress. A wide variety of metabolites (including lipids, fatty acids, amino acids, peptides, osmolytes) were identified as the potential biomarkers and subjected to metabolic pathway enrichment analysis. We discovered that, in the thermal-stressed P. decussata coral holobiont, (1) numerous metabolites in classes of lipids and amino acids significantly decreased, indicating an enhanced lipid hydrolysis and aminolysis that contributed to up-regulation in gluconeogenesis to meet energy demand for basic survival; (2) pantothenate and panthenol, two essential intermediates in tricarboxylic acid (TCA) cycle, were up-regulated, implying enhanced efficiency in energy production; (3) small peptides (e.g., Glu-Leu and Glu-Glu-Glu-Glu) and lyso-platelet-activating factor (lysoPAF) possibly implicated a strengthened coral immune response; (4) the down-regulation of betaine and trimethylamine N-oxide (TMAO), known as osmolyte compounds for maintaining holobiont homeostasis, might be the result of disruption of coral holobiont.

Short-chain fatty acids (SCFAs) are small molecules ubiquitous in nature. In mammalian guts, SCFAs are mostly produced by anaerobic intestinal microbiota through the fermentation of dietary fiber. Levels of microbe-derived SCFAs are closely relevant to human health status and indicative to gut microbiota dysbiosis. However, the quantification of SCFA using conventional chromatographic approaches is often time consuming, thus limiting high-throughput screening tests. Herein, we established a novel method to quantify SCFAs by coupling amidation derivatization of SCFAs with paper-loaded direct analysis in real time mass spectrometry (pDART-MS). Remarkably, SCFAs of a biological sample were quantitatively determined within a minute using the pDART-MS platform, which showed a limit of detection at the μM level. This platform was applied to quantify SCFAs in various biological samples, including feces from stressed rats, sera of patients with kidney disease, and fermentation products of metabolically engineered cyanobacteria. Significant differences in SCFA levels between different groups of biological practices were promptly revealed and evaluated. As there is a burgeoning demand for the analysis of SCFAs due to an increasing academic interest of gut microbiota and its metabolism, this newly developed platform will be of great potential in biological and clinical sciences as well as in industrial quality control.

Objectives Acinetobacter seifertii, a new member of the Acinetobacter baumannii group, has emerged as a cause of severe infections in humans. We investigated the clinical and molecular characteristics of A. seifertii. Patients and methods This retrospective study enrolled 80 adults with A. seifertii bloodstream infection (BSI) at four medical centres over an 8 year period. Species identification was confirmed by MALDI-TOF MS, rpoB sequencing and WGS. Molecular typing was performed by MLST. Clinical information, antimicrobial susceptibility and the mechanisms of carbapenem and colistin resistance were analysed. Transmissibility of the carbapenem-resistance determinants was examined by conjugation experiments. Results The main source of A. seifertii BSI was the respiratory tract (46.3%). The 28 day and in-hospital mortality rates of A. seifertii BSI were 18.8% and 30.0%, respectively. High APACHE II scores and immunosuppressant therapy were independent risk factors for 28 day mortality. The most common MLST type was ST553 (58.8%). Most A. seifertii isolates were susceptible to levofloxacin (86.2%), and only 37.5% were susceptible to colistin. Carbapenem resistance was observed in 16.3% of isolates, mostly caused by the plasmid-borne ISAba1-blaOXA-51-like genetic structure. A. seifertii could transfer various carbapenem-resistance determinants to A. baumannii, Acinetobacter nosocomialis and other A. seifertii isolates. Variations of pmrCAB and lpxCAD genes were not associated with colistin resistance of A. seifertii. Conclusions Levofloxacin and carbapenems, but not colistin, have the potential to be the drug of choice for A. seifertii infections. A. seifertii can transfer carbapenem-resistance determinants to other species of the A. baumannii group and warrants close monitoring.

CDK4/6 inhibitors (CDK4/6i) is well established as the current standard of care for hormone positive (HR(+)) metastatic breast cancer (mBC), in combination with endocrine therapy. CDK4/6i extend a chemotherapy-free, progression free survival (PFS) that preserves quality of life in patients. The most common side effect of CDK4/6i is myelosuppression, with neutropenia the most prevalent adverse effect, especially for palbociclib and ribociclib. In PALOMA-2 and MONALEESA-2, where neutropenia was prevalent (any grade neutropenia 79.5%, grade 3/4 neutropenia 66.5% in PALOMA-2, and any grade neutropenia: 74.3%, grade 3/4 55.3% in MONALEESA-2), although febrile neutropenia seldom occurred (1.8%). Several studies have proposed different genetic factors predisposing to CDK4/6 inhibitor induced neutropenia, including Duffy antigen polymorphisms, ABCB1 and ERCC1 polymorphisms (ABCB1_rs1128503, ABCB1_rs1045642, ERCC1_rs11615, ERCC1_rs3212986), CDK6 polymorphisms, and others. Subgroup studies from the PALOMA trials have suggested that Asian patients receiving palbociclib have higher rates of neutropenia, although the exact explanation is unknown. We conducted a retrospective analysis of 102 Taiwanese patients who received palbociclib for HR(+) mBC at the Taipei Veterans General Hospital for the clinical features, incidence and time course of neutropenia were analyzed. Significant neutropenia incidence was observed (> 95% of all grade neutropenia, 74.5% grade 3/4 neutropenia). In addition, in our clinical cohort, one of the patients was a long term peritoneal dialysis patient newly diagnosed of HR(+) mBC and started on Palbociclib, initially 125mg, later decreased dosage to 100mg after neutropenia occurrence. By Liquid chromatography–mass spectrometry (LC–MS), we quantified the levels of palbociclib in her serum and peritoneal fluid at various time points, while on different dosage use. To our knowledge, this is the first pharmacokinetics analysis on a peritoneal dialysis patient receiving CDK4/6i. To investigate a possible genetic association for the high prevalence of neutropenia, we queried the Taiwan biobank, a nationwide biospecimen repository with 129,586 healthy individual genome wide DNA sequencing data deposited. We investigated the prevalence of the 4 SNPs previously reported to be related to neutropenia in the PALOMA studies. By comparing the Taiwan biobank data to SNP databases from different ethnicities, we observed interesting findings on ethnicity differences of SNP distribution and higher prevalence of neutropenia SNPs. Collectively, in this study we report real world data, biobank genome wide analysis, and a novel report of pharmacokinetic study in a peritoneal dialysis patient, providing novel insights into the real world use of palbociclib and CDKi. Table 1. Median TTF of each subsequent therapy after PAL+ET Characteristics of the clinical cohort treated with palbociclib at TVGH Citation Format: Kuan-Jung Huang, Ting-Hao Kuo, Ta-Chung Chao, Chun-Yu Liu, Yi-Fang Tsai, Chi-Cheng Huang, Ling-Ming Tseng, Cheng-Chih Richard Hsu, Jiun-I Lai. High Incidence of Palbociclib Related Neutropenia in Asian Patients Associated with Genetic Polymorphisms [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-01-31.

Structural analysis of biomolecules is essential to natural product discovery, especially for precious biomaterials such as agarwood. However, one of the greatest challenges to the characterization of natural products is the profound cost in time and manpower to the structural elucidation of these highly diverse compounds. Here, we demonstrate a multi-modal mass spectrometric strategy, integrating matrix-assisted laser desorption ionization (MALDI) mass spectrometry imaging (MSI) and mass spectral molecular networking, to uncover agarwood natural products of Aquilaria sinensis trees. A simple workflow for preparing wood sections for MALDI-MSI analysis was demonstrated. Notably, tens of natural products in the agarwood region in wood stem section of A. sinensis were spatially revealed by MALDI-MSI. For the first time, such a great number of plant specialized metabolites is obtained by a single wood section MSI. Guided by the spatially resolved features, mass spectral molecular networking was subsequently applied for structural analysis of the agarwood natural products, in which three major classes of 2-(2-phenylethyl)chromones and their analogues were putatively characterized. These results suggest an efficient strategy to the dereplication of plant natural products.

Cellular lipidome is highly regulated through lipogenesis, rendering diverse double-bond positional isomers (C=C isomer) of a given unsaturated lipid species. In recent years, there are increasing reports indicating the physiological roles of C=C isomer compositions associated with diseases, while the biochemistry has not been fully understood due to the challenge in characterizing lipid isomers inherent to conventional mass spectrometry-based lipidomics. To address this challenge, we reported a universal, user-friendly, derivatization-based strategy, MELDI (mCPBA Epoxidation for Lipid Double-bond Identification), which enables both large-scale identification and spatial mapping of biological C=C isomers using commercial mass spectrometers without any instrument modification. With the developed liquid-chromatography mass spectrometry (LC-MS) lipidomics workflow, we elucidated more than 100 isomers among mono- and poly-unsaturated fatty acids and glycerophospholipids in both human serum, where novel isomers of low abundance were unambiguously quantified for the first time. The capability of MELDI-LC-MS in lipidome analysis was further demonstrated using the differentiated 3T3-L1 adipocytes, providing an insight into the cellular lipid reprogramming upon stearoyl-coenzyme A desaturase 1 (SCD1) inhibition. Finally, we highlighted the versatility of MELDI coupled with mass spectrometry imaging to spatially resolve cancer-associated alteration of lipid isomers in a metastatic mouse tissue section. Our results suggested that MELDI will contribute to current lipidomics pipelines with a deeper level of structural information, allowing us to investigate underlying lipid biochemistry.

Phenolic compounds are a large class of plant secondary metabolites with various health-promoting effects, and are known for their structural diversity. Therefore, high efficiency characterization of phenolic profiles is of key importance in identifying their potential bioactivity. In the present study, Global Natural Products Social (GNPS) Molecular Networking was applied to trace the phenolic compounds in plants, which allowed the characterization of 9 procyanidins and 11 flavonoid glycosides (di-, tri-, or tetra-saccharides of kaempferol, quercetin, isorhamnetin and myricetin) in litchi pulp extracts. Six compounds were reported for the first time in litchi pulp. In addition, quercetin-3-O-rutinoside-(1 → 2)-O-rhamnoside, the most abundant flavonoid glycoside in litchi pulp, was proved to have considerable α-glucosidase inhibitory activity, illustrating the anti-diabetic potential of phenolic-rich litchi pulp extracts.

Nanospray desorption electrospray ionization mass spectrometry is an ambient ionization technique that is capable of mapping proteins in tissue sections. However, high-abundant molecules or isobaric interference in biological samples hampers its broad applications in probing low-abundant proteins. To address this challenge, herein we demonstrated an integrated module that coupled pneumatic-assisted nanospray desorption electrospray ionization mass spectrometry with high-field asymmetric ion mobility spectrometry. Using this module to analyze mouse brain sections, the protein coverage was significantly increased. This improvement allowed the mapping of low-abundant proteins in tissue sections with a 5 μm spatial resolution enabled by computationally assisted fusion with optical microscopic images. Moreover, the module was successfully applied to characterize melanoma in skin tissues based on the enhanced protein profiles. The results suggested that this integrating module will be potentially applied to discover novel proteins in cancers.

Ambient ionization mass spectrometry (AIMS) has grown into a group of emerging analytical techniques that allow rapid, real-time, high-throughput, in situ, and in vivo analysis in many scientific fields including biomedicine, pharmaceuticals, and forensic sciences. While dozens of AIMS techniques have been introduced over the past two decades, their broad commercial and industrial use is still restricted by multiple challenges. In this Perspective, we discuss the most relevant technical challenges facing AIMS, i.e., reproducibility, quantitative ability, molecular coverage, sensitivity, and data complexity, and scientists' recent attempts to overcome these hurdles. Furthermore, we present future directions of AIMS from our perspective, including the necessity that efforts should be made to unravel blind biomolecules in routine analysis, the construction of a data depository for AIMS users, the full automation of pipelines for prospect integration in a robotic laboratory, the movement toward on-site tests, and the expansion of outreach to motivate government officials in policymaking. We anticipate that, with progress in these critical but immature areas, AIMS technology will keep evolving to become a more robust and user-friendly set of technologies and, consequently, be translated into everyday life practice.

This study aimed to explore the oxidation and transformation of the cephalosporins cefotaxime (CTX), cephalexin (CFX), cephradine (CFD), cephapirin (CFP) and cefazolin (CFZ) by δ-MnO2. The results showed that the MnO2 oxidation rate was promoted by environmental factors such as higher MnO2 loading, lower initial cephalosporin concentration and lower solution pH. The inhibitory effect occurred in the presence of dissolved organic matter and dissolved cations (inhibitory capacity: Mn2+ > Ca2+ > Mg2+ > Fe3+). Total organic carbon analysis indicated that the transformation byproducts of the cephalosporins are less reactive and persistent under MnO2 oxidation. Twelve transformation byproducts (9 CFP byproducts and 3 CTX byproducts) were identified, and two oxidative transformation pathways were proposed: one occurred in the cephem for CFP, and the other occurred at the substituent at the amine position for CTX. The effect of solar light on the oxidation of the five cephalosporin antibiotics by δ-MnO2 was also investigated, and the results indicated that the initial dissolution rate of δ-MnO2 under sunlight was approximately eight times faster than that in the dark in the presence of CFP.

Cefotaxime (CTX), cephalexin (CFX), cephradine (CFD), cephapirin (CFP), and cefazolin (CFZ) were selected as target cephalosporin antibiotics to study their oxidative transformation by δ-MnO2. Although they all have the same core structure (7-aminodesacetoxycephalosporanic acid), very different MnO2 oxidation rates were observed at pH 4 (the initial reaction rate constant kinit ranged from 0.014 to 2.6 h–1). An extensive investigation of the substructure compounds and byproduct analysis revealed that the oxidation mainly occurred at the following two sites on the core structure: (1) the sulfur atom in the cephem ring and (2) the carbon–carbon double bond (C═C) and its proximal carboxylic acid group. In the case of (2), when there is an acetyloxymethyl group at the C-3 position of the core structure, the formation of the keto-sulfone byproducts was inhibited. The overall results indicated that a substituent at the C-3 position could stabilize the core structure, which would result in a decrease in the oxid...

Demonstrated herein is an unprecedented porous template-assisted reaction at the solid–liquid interface involving bond formation, which is typically collision-driven and occurs in the solution and gas phases. The template is a TMA (trimesic acid) monolayer with two-dimensional pores that host fullerenes, which otherwise exhibit an insignificant affinity to an undecorated graphite substrate. The confinement of C84 units in the TMA pores formulates a proximity that is ideal for bond formation. The oligomerization of C84 is triggered by an electric pulse via a scanning tunneling microscope tip. The spacing between C84 moieties becomes 1.4 nm, which is larger than the edge-to-edge diameter of 1.1–1.2 nm of C84 due to the formation of intermolecular single bonds. In addition, the characteristic mass-to-charge ratios of dimers and trimers are observed by mass spectrometry. The experimental findings shed light on the active role of spatially tailored templates in facilitating the chemical activity of guest molec...

As human beings live longer, age-related diseases such as osteoporosis will become more prevalent. Intolerant side effects and poor responses to current treatments are observed. Therefore, novel effective therapeutic agents are greatly needed. Here, pyrazole derivatives were designed and synthesized, and their osteoclastogenesis inhibitory effects both in vitro and in vivo were evaluated. The most promising compound 13 with a 2-(dimethylamino)ethyl group inhibited markedly in vitro osteoclastogenesis as well as the bone resorption activity of osteoclasts. Compound 13 affected osteoclast's early proliferation and differentiation more than later fusion and maturation stages. In ovariectomized (OVX) mice, compound 13 can inhibit the loss of trabecular bone volume, trabecular bone number, and trabecular thickness. Moreover, compound 13 can antagonize OVX-induced reduction of serum bone resorption marker and then compensatory increase of the bone formation marker. To sum up, compound 13 has high potential to be developed into a novel therapeutic agent for treating osteoporosis in the future.