Fragmentation Patterns Research Articles

Mechanism and controlling factors of mass transport complexes migration: A case study of the mass transport complexes in the taranaki deep water basin, New Zealand

Mass transport Complexes (MTCs) form significant sediment accumulations in continental slopes, hold key insights for natural hazard prediction and offshore oil exploration. This paper uses high-definition 3D seismic data to reconstruct the seismic geomorphology and sedimentary dynamics of MTCs, meticulously exploring the depositional systems of the Tanaraki Basin, New Zealand. It deciphers by kinematic notation, seismic faciess, quantifies megaclast morphological characteristics, in conjunction with the basal slope and channel structure development as the migration or kinematics of MTCs. Five seismic facies categories and dynamic traits—compression ridges, thrust faults, slides, grooves and slope terraces are distinguished in MTCs. Based on attributes maps and geomorphological interpretations, MTCs is segmented into four zones, showing combined effects of levée, basal slopes, and megaclast clusters on its migration. Lithological and topographical variations along these features modulate erosion properties and MTCs mobility, with base height shifts guiding local migration trajectories. The results of megaclast parameters in Zones 1 and 3 tune our understanding of stress patterns and directionality shifts, highlighting the complex dynamics at play. Notably, the differential motion triggered by levees instigates longitudinal shear zones. At critical migration disparities, MTCs fracture at these weak points, discharging pore pressure and filling fractures with fines, birthing “promontory” formations marked by low-amplitude fills. This work, therefore, establishes a groundbreaking migratory model that synthesizes the impacts of levees height, rock type variability, and megaclasts accumulation intensity, depicting a fragmented migration pattern. This study not only enriches our grasp of MTCs behavior in deep-water contexts but also furnishes a robust scientific foundation and predictive tool for gauging the hazards that MTCs may pose to underwater structures, thus carrying substantial theoretical and applied significance.

Advancing Protein Analysis: A Low-Pressure Drift Tube Orbitrap Mass Spectrometer for Ultraviolet Photodissociation-Based Structural Characterization.

Owing to its ability to generate extensive fragmentation of proteins, ultraviolet photodissociation (UVPD) mass spectrometry (MS) has emerged as a versatile ion activation technique for the structural characterization of native proteins and protein complexes. Interpreting these fragmentation patterns provides insight into the secondary and tertiary structures of protein ions. However, the inherent complexity and diversity of proteins often pose challenges in resolving their numerous conformations. To address this limitation, we combined UVPD-MS with drift tube ion mobility, offering potential to acquire conformationally selective MS/MS information. A low-pressure drift tube (LPDT) Orbitrap mass spectrometer equipped with 193 nm UVPD capabilities enables the analysis of protein conformers through the analysis of arrival time distributions (ATDs) of individual fragment ions. ATDs of fragment ions are compared for different backbone cleavage sites of the protein or different precursor charge states to give information about regions of potential folding or elongation. This integrated platform offers promise for advancing our understanding of protein structures in the gas phase.

Discovering oxidized polar lipids in microalgae lipidome using liquid chromatography mass spectrometry approaches

Microalgae are rich in polar lipids, such as glycolipids, phospholipids and betaine lipids esterified with omega-3 polyunsaturated fatty acids (PUFA), which are prone to oxidation. Under stress conditions, the redox balance in microalgae is altered, leading to an abnormal production of reactive oxygen species (ROS) that can affect surrounding lipids. While few oxidized polar lipids have been described to play important roles in mammals and possess interesting bioactive properties, their occurrence in microalgae is poorly described, hindering their exploitation as novel bioactive compounds. To enhance our understanding of these lipids, we conducted a targeted analysis of oxidized polar lipids in lipid extracts obtained from five microalgae species: Chlorella vulgaris, Chlorococcum amblystomatis, Scendesmus obliquus, Nanochloropsis oceanica and Phaeodactylum ticornutum, using reverse-phase liquid chromatography mass spectrometry (RP-LC-MS). A detailed analysis of the LC-MS data identified 150 oxidized polar lipid species across different classes of phospholipids, glycolipids and betaine lipids in the five microalgae species. These modified oxidized lipids featured oxygenated species with 1–3 additional oxygen atoms in the fatty acyl chains. The predominant oxidized fatty acids esterified to these lipids were omega-3 eicosapentaenoic acid (EPA, 20:5 n-3) and α-linonelic acid (ALA, 18:3 n-3). Notably, most oxidized lipid species were identified in diacylglyceryl-N,N,N-trimethylhomoserine (DGTS) in C. amblystomatis, S. obliquus and N. oceanica, monogalactosyldiacylglycerol (MGDG) in P. tricornutum, and phosphatidylethanolamine (PE) in C. vulgaris. Furthermore, distinct fragmentation patterns across lipid classes allowed the unequivocal identification of oxidized polar lipids. These findings reveal a diverse array of oxidized polar lipids in microalgae, predominantly enriched with oxidized omega-3 PUFA, highlighting microalgae as a natural source of oxidized polar lipids that may serve as a natural reservoir of bioactive omega-3 oxylipins.

Multidimensional Fragmentomics Enables Early and Accurate Detection of Colorectal Cancer.

Colorectal cancer is frequently diagnosed in advanced stages, highlighting the need for developing approaches for early detection. Liquid biopsy using cell-free DNA (cfDNA) fragmentomics is a promising approach, but the clinical application is hindered by complexity and cost. This study aimed to develop an integrated model using cfDNA fragmentomics for accurate, cost-effective early-stage colorectal cancer detection. Plasma cfDNA was extracted and sequenced from a training cohort of 360 participants, including 176 patients with colorectal cancer and 184 healthy controls. An ensemble stacked model comprising five machine learning models was employed to distinguish patients with colorectal cancer from healthy controls using five cfDNA fragmentomic features. The model was validated in an independent cohort of 236 participants (117 patients with colorectal cancer and 119 controls) and a prospective cohort of 242 participants (129 patients with colorectal cancer and 113 controls). The ensemble stacked model showed remarkable discriminatory power between patients with colorectal cancer and controls, outperforming all base models and achieving a high area under the receiver operating characteristic curve of 0.986 in the validation cohort. It reached 94.88% sensitivity and 98% specificity for detecting colorectal cancer in the validation cohort, with sensitivity increasing as the cancer progressed. The model also demonstrated consistently high accuracy in within-run and between-run tests and across various conditions in healthy individuals. In the prospective cohort, it achieved 91.47% sensitivity and 95.58% specificity. This integrated model capitalizes on the multiplex nature of cfDNA fragmentomics to achieve high sensitivity and robustness, offering significant promise for early colorectal cancer detection and broad patient benefit. Significance: The development of a minimally invasive, efficient approach for early colorectal cancer detection using advanced machine learning to analyze cfDNA fragment patterns could expedite diagnosis and improve treatment outcomes for patients. See related commentary by Rolfo and Russo, p. 3128.

Distinct cellular uptake patterns of two anticancer unsymmetrical bisacridines and their metabolic transformation in tumor cells

Unsymmetrical bisacridines (UAs) represent a novel class of anticancer agents. Their high cytotoxicity towards multiple human cancer cell lines and inhibition of human tumor xenograft growth in nude mice signal their potential for cancer treatment. Therefore, the mechanism of their strong biological activity is broadly investigated. Here, we explore the efflux and metabolism of UAs, as both strongly contribute to the development of drug resistance in cancer cells. We tested two highly cytotoxic UAs, C-2028 and C-2045, as well as their glucuronic acid and glutathione conjugates in human cancer cell lines (HepG2 and LS174T). As a point of reference for cell-based systems, we examined the rate of UA metabolic conversion in cell-free systems. A multiple reaction monitoring (MRM)-mass spectrometry (MS) method was developed in the present study for analysis of UAs and their metabolic conversion in complex biological matrices. Individual analytes were identified by several features: their retention time, mass-to-charge ratio and unique fragmentation pattern. The rate of UA uptake and metabolic transformation was monitored for 24 h in cell extracts and cell culture medium. Both UAs were rapidly internalized by cells. However, C-2028 was gradually accumulated, while C-2045 was eventually released from cells during treatment. UAs demonstrated limited metabolic conversion in cells. The glucuronic acid conjugate was excreted, whereas the glutathione conjugate was deposited in cancer cells. Our results obtained from cell-free and cell-based systems, using a uniform MRM-MS method, will provide valuable insight into the mechanism of UA biological activity in diverse biological models.

MRNA Fragmentation Pattern Detected by SHAPE.

The success of messenger RNA (mRNA) vaccines in controlling COVID-19 has warranted further developments in new technology. Currently, their quality control process largely relies on low-resolution electrophoresis for detecting chain breaks. Here, we present an approach using multi-primer reverse transcription sequencing (MPRT-seq) to identify degradation fragments in mRNA products. Using this in-house-made mRNA containing two antigens and untranslated regions (UTRs), we analyzed the mRNA completeness and degradation pattern at a nucleotide resolution. We then analyzed the sensitive base sequence and its correlation with the secondary structure. Our MPRT-seq mapping shows that certain sequences on the 5' of bulge-stem-loop structures can result in preferential chain breaks. Our results agree with commonly used capillary electrophoresis (CE) integrity analysis but at a much higher resolution, and can improve mRNA stability by providing information to remove sensitive structures or sequences in the mRNA sequence design.

Chromatographic fingerprinting of epiphytic fungal strains isolated from Withania somnifera and biological evaluation of isolated okaramine H.

Medicinal plants are "goldmines" of natural products, and continue to provide key scaffolds for drug development. They have immense therapeutic potential, encapsulating a plethora of metabolites within them, which have yet to be explored. Withania somnifera (L.) Dunal is one such medicinal plant known since time immemorial for its therapeutic activity in the Ayurveda system of medicine. Studies have revealed Nature's marvel of these medicinal plants harbouring endophytic and epiphytic microorganisms from phyllosphere to rhizosphere. Chromatographic fingerprinting was carried out using HPTLC and HPLC on five epiphytic strains isolated from the leaves, stem and fruits of Withania somnifera. Out of five filamentous fungi, one fungus identified as Aspergillus aculeatus S20 was well explored. An indole alkaloid, okaramine H, was isolated using systematic chromatographic investigation at a retention time of 26.278 min showing λmax at 206, 236, 284 and 370 nm. Confirmation was achieved using NMR and mass spectrometry (MS) as analytical techniques. Structure elucidation was done by studying the fragmentation pattern using MS/MS and an accurate mass was determined using HR-ESI-QTOF-MS showing m/z of 521.2546 [M + H]+. The percentage purity of isolated okaramine H was found to be >90. Well known for its insecticidal activity, okaramine H was explored for its antileishmanial activity against the Leishmania donovani parasite for the first time. Under in vitro conditions, the compound showed an inhibitory effect on Leishmania donovani promastigotes with an IC50 of 147 μg mL-1.

Establishment and validation of circulating cell-free DNA signatures for nasopharyngeal carcinoma detection

Early detection of nasopharyngeal carcinoma (NPC) poses a significant challenge. The absence of highly sensitive and specific diagnostic biomarkers for nasopharyngeal carcinoma contributes to the unfavourable prognosis of NPC patients. Here, we aimed to establish a non-invasive approach for detecting NPC using circulating cell-free DNA (cfDNA). We investigated the potential of next-generation sequencing (NGS) of peripheral blood cells as a diagnostic tool for NPC. We collected data on genome-wide nucleosome footprint (NF), 5'-end motifs, fragmentation patterns, CNV information, and EBV content from 553 Chinese subjects, including 234 NPC patients and 319 healthy individuals. Through case-control analysis, we developed a diagnostic model for NPC, and validated its detection capability. Our findings revealed that the frequencies of NF, fragmentation, and motifs were significantly higher in NPC patients compared to healthy controls. We developed an NPC score based on these parameters that accurately distinguished NPC from non-NPC cases according to the American Joint Committee on Cancer staging system from non-NPC (validation set: area under curve (AUC)=99.9% (95% CI: 99.8%-100%), se: 98.15%, sp: 100%). This model showed superior performance over plasma EBV DNA. Additionally, the NPC score effectively differentiated between NPC patients and healthy controls, even after clinical treatment. Furthermore, the NPC score was found to be independent of potential confounders such as age, sex, or TNM stage. We have developed and verified a non-invasive approach with substantial potential for clinical application in detecting NPC. A full list of funding bodies that contributed to this study can be found in Funding section.

The effect of habitat fragmentation on Malay tapir abundances in Thailand’s protected areas

Habitat loss and fragmentation in tropical regions are major threats to the persistence of endangered Malay tapir (Tapirus indicus). The Malay tapir distribution is largely constrained to fragmented habitats inside protected areas. However, it is unclear how the spatial patterns of habitat fragmentation affect its relative abundance. Here, we investigated the effects of habitat fragmentation on Malay tapir relative abundance in Thailand. We first quantified the spatial patterns of habitat fragmentation within nine of Thailand’s protected areas. Second, we assessed the relationship of fragmentation metrics and relative abundance of Malay tapirs. Third, we identified the relative importance of the fragmentation metrics in explaining relative abundance. We found that tapir abundance remained unexpectedly high in the Southern forest complex despite the fact that tapir habitats were significantly more fragmented there than in the protected area in the western forest complex (p < 0.05). Additionally, we found a significantly negative relation with clumpiness index (R2 = 0.51, p < 0.05). This suggests that other factors may also be influencing their populations, so that the Southern protected areas provide preferred habitat with higher relative proportions of moist evergreen forest, large habitat patch size, precipitation, and elevation. It highlights the importance of interconnected habitat for tapirs, and the benefit of conservation efforts in small, less recognized protected areas.

Biotransformation of Sumatriptan by Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa and Salmonella enterica subsp. enterica.

This study aimed at the biotransformation of sumatriptan by Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa and Salmonella enterica subsp. enterica and the identification of the drug metabolites by liquid chromatography-mass spectrometry. The drug was incubated with the organisms in tryptic soya broth at 37 °C. The broth was filtered and subjected to liquid chromatography-mass spectrometry. The metabolites identified by the use of mass spectral (+ve ion mode) fragmentation patterns were (3-methylphenyl)methanethiol (Bacillus subtilis), 1-(4-amino-3-ethylphenyl)-N-methylmethanesulfonamide (Salmonella enterica subsp. enterica) and 1-{4-amino-3-[(1E)-3-(dimethylamino)prop-1-en-1-yl]phenyl}methanesulfinamide (Salmonella enterica subsp. enterica, Bacillus subtilis, Pseudomonas aeruginosa, Staphylococcus aureus). These metabolites exhibit high gastrointestinal absorption, no blood-brain barrier permeability (except (3-methylphenyl)methanethiol), a bioavailability score of 0.55 and no inhibitory effect on CYP2C19, CYP2C9, CYP2D6, CYP3A4 or cytochrome P450 1A2 (except (3-methylphenyl)methanethiol), as determined by SwissADME software ver. 2024. The metabolites appear to be more toxic than the parent drug, as suggested by their calculated median lethal dose values. All four organisms under investigation transformed sumatriptan to different chemical substances that were more toxic than the parent drug.

Study of phenanthrenes from their unique mass spectrometric behavior through quantum chemical calculations to liquid chromatographic quantitation

Phenanthrenes and their derivatives have biological relevance owing to their antimicrobial, antioxidant, and cytotoxic effects on cancer cells. They can be efficiently analyzed through ultrahigh-performance liquid chromatography coupled to tandem high-resolution mass spectrometry (UHPLC–MS/HRMS). Herein, we first studied the unique fragmentation behavior of phenanthrenes based on direct infusion MS/HRMS analysis. As a newly described phenomenon, “organ pipe distribution”, we found a structural connection linking their unique fragmentation pattern to serial H radical losses. The bonds responsible for this behavior were identified through quantum chemical calculations using a stepwise approach. Furthermore, the chromatographic aspect of this study was enhanced by developing, validating, and applying a new unscheduled targeted UHPLC–MS/HRMS method for quantifying phenanthrenes in Juncus compressus herb. Targeted compounds were efficiently separated within 4 min upon utilizing the Accucore C30 column, and the unscheduled targeted analytical approach afforded five new isomers. Compounds 1 (effususol), 3 (dehydroeffusol), and 6 (7-hydroxy-1-methyl-2-methoxy-5-vinyl-9,10-dihydrophenanthrene) had their linearity limits determined within 10–5000 nM, and Compounds 2 (effusol), 4 (juncusol), 5 (effususin A), and 7 (compressin A) within 25–5000 nM. The coefficients of variation for precision ranged from 1.4 % to 15.2 %. The obtained matrix effects and accuracy values were also within acceptable ranges. Compounds 2 (effusol) and 3 (dehydroeffusol) were present in both methanolic and dichloromethanolic extracts of Plants 1 and 3 at the highest concentrations. Furthermore, the relationship between phenanthrene fingerprints, obtained through ANOVA statistical analysis of quantitative data, and the geographical location of herbs was also established.

Exploring methandienone metabolites generated via homogenized camel liver: Advancements for anti-doping applications through High Resolution-Liquid Chromatography Mass Spectrometry analysis.

Anabolic steroids, also known as anabolic-androgenic steroids (AAS), encompass steroidal androgens such as testosterone, as well as synthetic counterparts with similar structures and effects. The misuse of AAS has increased over the years, leading to ethical and welfare concerns in sports. The World Anti-Doping Agency (WADA) and the International Federation for Equestrian Sports (FEI) have banned AAS in relevant sports. Methandienone is one of the most identified anabolic androgenic steroids in sports drug testing, Therefore, reliable detection methods are crucial for effective doping control and maintaining the integrity of the sports. This study explores the use of homogenized camel liver for detecting methandienone metabolites in camels. The biotransformation pathways of methandienone in homogenized camel liver tissues are analyzed using Liquid Chromatography-High Resolution Mass Spectrometry (LC-HRMS) to identify and characterize the phase I and phase II metabolites. Chromatographic separation was achieved using a Thermo-Hypersil C18 column. The study has identified 11 methandienone metabolites (M1-M11), this includes 10 phase I and one phase II metabolite. A glucuronic acid conjugate of methandienone was observed in this study, but no sulfonic acid conjugations were found. The metabolites and their possible chemical structures, along with their fragmentation patterns are confirmed using MSMS (MS2) experiments in data-independent acquisition (DIA) mode. These findings serve as a vital tool for the rapid detection of methandienone, combating its illicit use in camel racing. Comprehensive screenings covering both the parent drug and its metabolites are recommended to improve detection accuracy and ensure regulatory compliance in sports doping. Future research should explore methandienone's metabolite profile in administered camel samples.

Bridging the Diagnostic Gap for Hypermobile Ehlers-Danlos Syndrome and Hypermobility Spectrum Disorders: Evidence of a Common Extracellular Matrix Fragmentation Pattern in Patient Plasma as a PotentialBiomarker.

Diagnosing hypermobile Ehlers-Danlos syndrome (hEDS) and hypermobility spectrum disorders (HSD), common overlapping multisystemic conditions featuring symptomatic joint hypermobility, is challenging due to lack of established causes and diagnostic tools. Currently, the 2017 diagnostic criteria for hEDS are used, with non-qualifying cases classified as HSD, although the distinction remains debated. We previously showed extracellular matrix (ECM) disorganization in both hEDS and HSD dermal fibroblasts involving fibronectin (FN), type I collagen (COLLI), and tenascin (TN), with matrix metalloproteinase-generated fragments in conditioned media. Here, we investigated these fragments in patient plasma using Western blotting across diverse cohorts, including patients with hEDS, HSD, classical EDS (cEDS), vascular EDS (vEDS), rheumatoid arthritis (RA), psoriatic arthritis (PsA), and osteoarthritis (OA), and healthy donors, uncovering distinctive patterns. Notably, hEDS/HSD displayed a shared FN and COLLI fragment signature, supporting their classification as a single disorder and prompting reconsideration of the hEDS criteria. Our results hold the promise for the first blood test for diagnosing hEDS/HSD, present insights into the pathomechanisms, and open the door for therapeutic trials focused on restoring ECM homeostasis using an objective marker. Additionally, our findings offer potential biomarkers also for OA, RA, and PsA, advancing diagnostic and therapeutic strategies in these prevalent joint diseases.

Field evidence and indicators of rockfall fragmentation and implications for mobility

Rockfall fragmentation can play an important role in hazard studies and the design of protective measures. However, the current lack of modeling tools that incorporate rock fragmentation mechanics is a limitation to enhancing studies and design. This research investigates the fragmentation patterns of rockfalls and analyzes the resulting distribution of fragment sizes within corresponding rockfall deposits. We focus on small rock fragments, which provide insights into the dynamics of the rockfall event and can be used as input for numerical modeling. We analyzed multiple rockfall events from locations worldwide, each exhibiting different degrees of fragmentation. Using image analysis techniques, we mapped all visible blocks, determined their volumes, and measured the distances they travelled from the initial point of impact. A key finding is the identification of three indicators of fragmentation. First, in cases where fragmentation was largely absent, we observed a trend of increasing block size with distance from the impact point or source area, which aligns with previously published findings. However, for energetic rockfall events characterized by intense fragmentation, we observed that small fragments exhibited longer travel distances compared to larger fragments. This distinction allowed us to differentiate blocks primarily resulting from the disaggregation process from those primarily resulting from dynamic fragmentation, with implications for rockfall mobility. Second, although the size distribution of rockfall deposits exhibits a power-law scaling for volumes larger than a minimum size threshold corresponding to a rollover of the distribution, in some case studies a deviation from power-law scaling is observed, indicating a process of larger block comminution due to fragmentation. Third, we found that rockfalls with fragmentation experience reduced mobility, indicated by higher reach angles, and higher lateral dispersion showing a wider distribution of trajectories. We interpret these findings as being directly related to the energy-consuming nature of fragmentation, which prevents farther deposition of fragmented rock blocks.

Pheno- and Genotypic Epidemiological Characterization of Vancomycin-Resistant Enterococcus faecium Isolates from Intensive Care Unit Patients in Central Türkiye.

Vancomycin-resistant Enterococcus faecium (VRE) has been detected in Türkiye. Only limited information is available on its dissemination in the central regions of the country. This study describes the first epidemiological characterization of VRE clinical isolates detected in patients in a hospital in the province of Aksaray. In this one-year study conducted between 2021 and 2022, stool samples from intensive care unit patients were screened for VRE using the phenotypic E-test method, and the antibiotic sensitivity test was analyzed by using the VITEK® 2 system. A molecular assay for confirmation of species level was carried out by 16S rRNA gene-based sequencing and testing for antibiotic resistance (vanA or vanB) and virulence factor-encoding genes (esp, asa1, and hyl). Further, genotypic characterization was determined by macro-restriction fragment pattern analysis (MRFPA) of genomic DNA digested with SmaI restriction enzyme. Of the total 350 Enterococcus positive patients from different hospital intensive care units, 22 (6.3%) were positive for VRE using the phenotypic E-test method. All isolates showed resistance to ampicillin, ciprofloxacin, vancomycin, and teicoplanin and positive amplification for the vanA gene. However, none of the isolates was positive for the vanB gene. The most prevalent virulence gene was esp. The results indicate that the isolates are persistent in the hospital environment and subsequently transmitted to hospitalized patients, thus representing challenges to an outbreak and infection control. These study results would also help formulate more effective strategies to reduce the transmission and propagation of VRE contamination in various hospital settings.

Study on Selenium Assimilation and Transformation in Radish Sprouts Cultivated Using Maillard Reaction Products.

The organic selenium (Se), particularly in the form of selenoamino acids, in non-edible sections or by-products of Se-enriched plants, has the potential to generate Maillard reaction products (MRPs) during thermal treatment or fermentation. To elucidate the recycling process of organic selenium in foods and improve the utilization rate of Se, the biotransformation of organic selenium was studied by the cultivation of edible radish sprouts with Se-MPRs. Maillard reactions were simulated using selenoamino acids (SeAAs; selenomethionine and methylselenocysteine) and reducing sugars (glucose and fructose) for preparing Se-MRPs. The structures of the possible dehydrated Se-MRPs were analyzed using a HPLC-ESI-MS/MS system based on their fragmentation patterns and Se isotopic characteristics. Se absorption by the radish sprouts cultivated using Se-MRPs was estimated by the corresponding Se in the SeAAs and the total Se contents. The capabilities of SeAA transformation and total Se assimilation by the sprouts were related to the substrate composition during the Se-Maillard reaction. A particular Se-MRP (selenomethionine + fructose) increased SeAAs transformation by 33.8% compared to selenomethionine. However, glucose and fructose seemed to inhibit the transformation of the Se-MRPs to SeAAs by 10.0 to 59.1% compared to purified Se-MRPs. These results provide key references for the efficient utilization of organic Se in the cultivation of Se-enriched sprouts.

Spatial Modeling of Insect Pollination Services in Fragmented Landscapes.

Pollination mapping and modeling have opened new avenues for comprehending the intricate interactions between pollinators, their habitats, and the plants they pollinate. While the Lonsdorf model has been extensively employed in pollination mapping within previous studies, its conceptualization of bee movement in agricultural landscapes presents notable limitations. Consequently, a gap exists in exploring the effects of forest fragmentation on pollination once these constraints are addressed. In this study, our objective is to model pollination dynamics in fragmented forest landscapes using a modified version of the Lonsdorf model, which operates as a distance-based model. Initially, we generated several simulated agricultural landscapes, incorporating forested and agricultural habitats with varying forest proportions ranging from 10% to 50%, along with a range of fragmentation degrees from low to high. Subsequently, employing the modified Lonsdorf model, we evaluated the nesting suitability and consequent pollination supply capacity across these diverse scenarios. We found that as the degree of forest fragmentation increases, resulting in smaller and more isolated patches with less aggregation, the pollination services within landscapes tend to become enhanced. In conclusion, our research suggests that landscapes exhibiting fragmented forest patch patterns generally display greater nesting suitability due to increased floral resources in their vicinity. These findings highlight the importance of employing varied models for pollination mapping, as modifications to the Lonsdorf model yield distinct outcomes compared to studies using the original version.

UPLC-Q-TOF-MS/MS analysis of ophiobolins sesterterpenoids and bioactive analogs from Bipolaris eleusines

In order to elucidate the mass fragmentation patterns and unveil more undescribed ophiobolin analogs, the mass fragmentation patterns of ophiobolins were analyzed based on UPLC-Q-TOF-MS/MS experiments. Different kinds of rearrangements (including McLafferty rearrangement) were the main cleavage patterns. Twenty-six (9–31) analogs were then tentatively characterized based on their mass analysis, and three undescribed ophiobolins (6–8) and a known analogue (5) were isolated in target. Compound 5 possesses a rare polycyclic carbon skeleton only recently reported, and compound 6 contains an undescribed lactone ring system fused with A/B ring at C-3/C-21, whereas compounds 7 and 8 have a peroxyl group in the side chain, which is the first reported in all ophiobolins. Compounds 5 and 7 displayed significant cytotoxicity against MCF-7 cancer cells.

Phylogeography of a herbal Pinellia ternata reveals repeated range expansions and inter/postglacial recolonization routes on the fragmented distribution pattern in China.

Most plant phylogeographic studies in China have focused on the importance of genetic divergence and where should the shelter be located. Little attention has been paid to range expansion and recolonization routes in this region. In this study, two cpDNA fragments (psbK-psbI and trnL-F), two pairs of nuclear gene sequences (ITS and ETS), and nine pairs of SSR molecular markers were used, combined with Bayesian Skyline Plot method, gene barrier analysis, and species distribution models to explore the phylogeographical pattern, potential expansion routes and population dynamic history of Pinellia ternata from 22 population. The results showed that phylogeograhical pattern and genetic structure for P. ternata are effected by environmental heterogeneity and climate fluctuation, and it can be divided into two groups (Southwest group, Central and Eastern group) and thus there are at least two glacial refugia in China. Three expanding routes within groups were explored to contribute to the phylogeogrephic pattern of P. ternata based on the geographical distribution and network analysis of haplotypes. In a word, our study reveals repeated range expansions and inter/postglacial recolonization routes on the fragmented distribution pattern in China and resolves the refugia distributing in China and has also certain reference value for the protection of the medicinal plant P. ternata.

Structural characterization of nitazene analogs using electron ionization-mass spectrometry (EI-MS)

Nitazene analogs are among the most recent and potent additions to the novel synthetic opioid (NSO) market, and new analogs continue to emerge. Seized drug analysis commonly utilizes gas chromatography-electron ionization-mass spectrometry (GC-EI-MS), so it is therefore imperative to understand how nitazene analogs behave under EI-MS conditions, and how substitution at various sites on the molecule may impact the resulting EI mass spectra. This study characterizes the EI fragmentation behavior of 20 representative nitazene analogs that contain differing substitutions and proposes rational mechanisms to explain the observed behavior.A general EI fragmentation pathway for nitazene analogs was proposed, with the most common nitazene fragment ions being observed at m/z 86, m/z 107, m/z 58, and m/z 77. Characteristic ions were determined for different substitution groups, enabling the identification of diethyl, desethyl, pyrrolidine, and piperidine substitutions at the amine moiety, and different alkoxy chain lengths at the aromatic ring of the benzyl group. Mechanisms for the formation of these characteristic ions were proposed with the aid of isotopically labeled standards and high-resolution mass spectrometry measurements. To help with the interpretation of EI mass spectra for nitazene analogs, decision trees were developed that encompass the characteristic fragment ions observed for substitutions to the amine moiety and benzyl group, with additional criteria provided for substitutions to the benzimidazole moiety. This study summarizes the fragmentation patterns and characteristic fragment ions in the EI mass spectra of 20 representative nitazene analogs, which will aid the seized drug community in identifying novel nitazene analogs.