Distinct Composition Research Articles

Fast spectroscopic and multisensor methods for analysis of glucosamine and hyaluronic acid in dietary supplements

There is a lack of fast and inexpensive analytical methods for quantification of key ingredients in dietary supplements. Here we explore the potential of near infrared (NIR) spectrometry, attenuated total reflection infrared (ATR-IR) spectrometry and potentiometric multisensor system (MSS) in quantitative determination of glucosamine and hyaluronic acid in commercial samples of dietary supplements. All three methods have demonstrated their applicability for this task when combined with chemometric data processing. Principal Component Analysis (PCA) revealed similarities across the three techniques, indicating the presence of distinct sample compositions. Partial least squares (PLS) models were constructed for glucosamine and hyaluronic acid quantification. The root mean square error of cross validation (RMSECV) for glucosamine quantification varied between 7.7 wt% and 8.9 wt%. NIR spectrometry has demonstrated the best accuracy for hyaluronic acid (RMSECV = 9.9 wt%), while ATR-IR and MSS yielded somewhat worse performance with RMSECV values of 12.1 and 11.3 wt%, respectively. The findings of this study indicated that NIR, ATR-IR and MSS exhibit reduced accuracy in comparison to complex and high-precision analytical techniques. However, they can be employed for the rapid, semi-quantitative evaluation of glucosamine and hyaluronic acid in dietary supplements, with the possibility of integration into routine quality control procedures.

Abstract C040: Spatial transcriptomics unveils disparities in tumor microenvironment dynamics between breast cancer responders and non-responders

Abstract Spatial transcriptomics is revolutionizing our understanding of cellular dynamics and interactions in the tumor microenvironment (TME). By mapping distinct cellular populations and their interactions, we can gain valuable insights into tumor behavior. To investigate these dynamics in breast cancer, we conducted Xenium In-situ spatial transcriptomics on twenty formalin-fixed paraffin-embedded (FFPE) samples taken from eight patients undergoing neoadjuvant chemotherapy. These samples have been taken pre-treatment, mid-treatment and post-treatment from four cases with pathological complete response (pCR), and four cases with residual disease (RD) at time of surgery. Our analyses have found distinct cellular composition changes between pCR and RD cases. Patients with RD demonstrated an increase in endothelial, perivascular-like (PVL) and epithelial cells from pre- to post-treatment. This was accompanied by a decrease in myeloid and malignant epithelial cells at mid-treatment. In contrast, patients with pCR demonstrated increases in cancer-associated fibroblasts (CAFs) and myeloid cells, with reductions in plasmablasts and cancer epithelial cells at mid-treatment. This suggests that an increase in CAF and myeloid cells observed between pre-treatment and mid-treatment samples may be predictive of response. We performed ligand-receptor (LR) analyses, which demonstrated diverse myeloid interactions in RD cases and diverse CAF interactions in pCR cases in pre-treatment samples. Mid-treatment samples exhibited a decrease in interactions for CAFs, myeloid and T cells in pCR and RD cases. The most frequently identified CAF LR interactions, as senders, were between TGFB1/TGFB3 and TGFBR1/TGFBR2, while the most frequently identified myeloid LR interactions were between PDCD1LG2 - PDCD1 (encoding PDL2 & PD1), CCL8 - ACKR1 (encoding Atypical Chemokine Receptor 1) and CCL2 - ACKR1. Our findings indicate that the dynamic changes in cellular composition and interactions within the TME differs between responders and non-responders. To further explore these differences, we plan to perform spatially constrained analyses to identify unique cellular niches that may serve as potential biomarkers for informing novel therapeutic strategies. Citation Format: Jeremy Mo, Hanyun Zhang, Kate Harvey, Alexander Swarbrick. Spatial transcriptomics unveils disparities in tumor microenvironment dynamics between breast cancer responders and non-responders [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr C040.

Transcriptome-based network analysis related to regulatory T cells infiltration identified RCN1 as a potential biomarker for prognosis in clear cell renal cell carcinoma.

Regulatory T cells (Tregs) play a critical role in shaping the immunosuppressive microenvironment within tumors. Investigating the role of Tregs in Clear cell renal cell carcinoma (ccRCC) is crucial for identifying prognostic markers and therapeutic targets for ccRCC. Weighted gene co-expression network analysis (WGCNA) was utilized to pinpoint modules related to Treg infiltration in TCGA-KIRC samples. Following this, consensus clustering was employed to derive two clusters associated with Treg infiltration in ccRCC. A prognostic model was then developed using the gene module associated with Treg infiltration. We then evaluated the ability of the prognostic model to predict ccRCC overall survival and demonstrated that RCN1 can be used as a target to predict ccRCC prognosis. We deduce that the two clusters associated with Treg infiltration exhibit distinct compositions of the immune microenvironment, pathway activations, prognosis, and drug sensitivities commonly utilized in ccRCC treatment. Furthermore, a 7-gene model risk score, developed based on ccRCC Treg infiltration, proved to be a reliable prognostic marker in both training and validation cohorts. Additionally, survival analysis indicated that RCN1 serves as a reliable prognostic factor for ccRCC. Single-cell sequencing analysis revealed that RCN1 is predominantly expressed in tumor cells. A pan-cancer analysis highlighted that RCN1 is linked with poor prognosis and the activation of inflammatory response pathways across various cancers. We developed a prognostic model associated with Treg infiltration, which facilitates the clinical categorization of ccRCC progression. Moreover, our findings underscore the significant potential of RCN1 as a ccRCC biomarker.

Abstract 4135951: Single Nuclei RNA Sequencing Reveals Distinct Cellular Composition of Pericoronary Adipose Tissue

Introduction: Adipose tissue is a metabolically active organ with local paracrine interactions on adjacent tissues. Pericoronary adipose tissue (PcAT) is an emerging cardiovascular disease (CVD) risk factor and likely has paracrine effects on coronary vasculature that may promote coronary artery disease (CAD) development. PcAT may be functionally and clinically distinct from epicardial adipose tissue (EAT) given its proximity to the coronary artery adventitia. The cellular composition of PcAT and EAT and whether they have unique inflammatory cell signatures and functional expression at a single cell level has not been explored. Hypothesis: PcAT will have diverse cellular composition with heightened inflammatory cell content compared to EAT. Methods: Visual dissection of paired EAT not adjacent to an epicardial coronary artery and PcAT in direct apposition to an epicardial artery (left anterior descending artery) was performed from a single human heart immediately after explant (prior to heart transplantation). Nuclei were isolated using the Chromium Nuclei Isolation Kit (10x Genomics) with RNAse inhibitor. Cells were counted with a Cellometer K2 and Chromium Next GEM Single Cell libraries were prepared, followed by reverse transcription, PCR and NovaSeq 6000 platform sequencing. Raw sequence reads from single nuclei RNA-seq (snRNA-seq) were processed and after QC filtering, cells were clustered using Seurat. Clusters were annotated using singleR. Results: In PcAT and EAT, >7000 cells were successfully extracted with 73755 and 48750 mean snRNA-seq reads per cell, respectively. snRNA-seq cellular composition analysis delineated a heightened inflammatory milieu and distinct cellular composition of human PcAT vs. EAT. A UMAP (Uniform Manifold Approximation and Projection) plot displays higher inflammatory cell infiltrate with a neutrophil predominance and lesser adipocyte composition in PcAT compared with EAT ( Figure 1) . Conclusions: We have generated snRNA-seq data from human PcAT and shown distinct cellular composition compared to EAT. Given the proximity of PcAT to coronary vasculature, these results are supportive of paracrine inflammatory effects and highlight adipose tissue biology in cardiovascular disease. Understanding this biology may identify novel therapeutic targets for CVD.

Large-scale metagenomic analysis of oral microbiomes reveals markers for autism spectrum disorders.

The link between the oral microbiome and neurodevelopmental disorders remains a compelling hypothesis, still requiring confirmation in large-scale datasets. Leveraging over 7000 whole-genome sequenced salivary samples from 2025 US families with children diagnosed with autism spectrum disorders (ASD), our cross-sectional study shows that the oral microbiome composition can discriminate ASD subjects from neurotypical siblings (NTs, AUC = 0.66), with 108 differentiating species (q < 0.005). The relative abundance of these species is highly correlated with cognitive impairment as measured by Full-Scale Intelligence Quotient (IQ). ASD children with IQ < 70 also exhibit lower microbiome strain sharing with parents (p < 10-6) with respect to NTs. A two-pronged functional enrichment analysis suggests the contribution of enzymes from the serotonin, GABA, and dopamine degradation pathways to the distinct microbial community compositions observed between ASD and NT samples. Although measures of restrictive eating diet and proxies of oral hygiene show relatively minor effects on the microbiome composition, the observed associations with ASD and IQ may still represent unaccounted-for underlying differences in lifestyleamong groups. While causal relationships could not be established, our study provides substantial support to the investigation of oral microbiome biomarkers in ASD.

ANGI-08. SPATIAL TRANSCRIPTOMIC COMPARISONS OF GLIOBLASTOMA TISSUE REVEAL UPREGULATION OF NEURODEVELOPMENTAL PATHWAYS AND SYNAPTIC GENES IN INFILTRATING TUMOR CELLS

Abstract Glioblastoma remains one of the deadliest brain malignancies. First-line therapy consists of maximal surgical tumor resection, chemotherapy, and radiotherapy. Malignant cells escape surgical resection by migrating into the surrounding healthy brain tissue, where they give rise to the recurrent tumor. Gene expression profiling allows glioblastoma tumor cores to be classified into mesenchymal, proneural, and classical subtypes, each with distinct genetic alterations and cellular compositions. In contrast, the adjacent brain parenchyma where infiltrating malignant cells escape surgical resection is less characterized in patients. Using single-cell and multicellular resolution spatial transcriptomics on tissues from both the tumor core and infiltrated brain tissue (n = 11), we compared the transcriptional profiles of malignant cells in these regions. Malignant cells near regions with microvascular proliferation showed increased expression of genes related to vascular homeostasis. Within tumor cores, proneural and mesenchymal subtypes exhibited distinct spatial gene expression patterns, although these differences were reduced in the infiltrated brain tissue, apart from gene expression due to chromosomal alterations specific to the proneural subtype. We identified two transcriptional patterns of brain infiltration, with the dominant pattern showing a transition from mesenchymal to proneural states. This transition was accompanied by increased expression of genes linked to neurodevelopmental pathways and glial cell differentiation. Additionally, one gene module upregulated in infiltrating malignant cells was predictive of poor patient survival and enriched for genes associated with differentiated neuronal cells. Together, our findings provide an updated view of the spatial landscape of glioblastomas and infiltrated brain tissue, furthering our understanding of the malignant cells that invade healthy brain. This insight offers new avenues for targeted therapy after surgical resection of the primary tumor.

Investigating the Timing of Carbonate Precipitations and Their Potential Impact on Fossil Preservation in the Hell Creek Formation

Because fossilized skeletal remains and enclosing sedimentary rocks experience similar diagenetic conditions (i.e., temperature, pressure, and pore fluid interaction,) enclosing sedimentary rocks may provide insight into bone diagenesis. A fossil assemblage, including in situ dinosaur fossils, was discovered in Makoshika State Park near Glendive, MT. Fossil-bearing sandstone is a crevasse splay deposit, and fossils show no sorting or preferred orientation. Bone-bearing sandstone exhibits evidence for intense diagenesis, suggesting a maximum temperature of ~90 °C. Concretion associated with fossils includes two distinctive matrices: dark- and light-colored matrices. Another concretion was found in channel sandstone near the base of the outcrop. These carbonate phases have distinctive isotopic compositions; δ13C values for dark-colored matrices, light-colored matrices, and spheroidal concretion are −7.5, 2.1, and −22.4‰ (VPDB), respectively, and their δ18O values are 16.4, 25.9, and 17.8‰ (VSMOW), respectively. In contrast, fossilized bone δ13C and δ18O values were −4.4‰ (VPDB) and 20.6‰ (VSMOW), respectively, suggesting fractionation with pore fluid was limited. Early carbonate precipitation evidenced by grain coating may have reduced interaction between pore fluids and fossils. Although concretion formation and permineralization do not appear to directly aid in fossil preservation, concretions preserve valuable evidence for diagenetic history.

Ethnic Rhinoplasty in the Brazilian Population: Current Concepts.

The large mixture of races in Brazil gives the nose its distinctive composition, which makes rhinoplasty difficult for these patients. Every patient should have their anatomy thoroughly examined on an individual basis, as there is no unique strategy that works for all situations. This is a narrative overview of the last 10 years' worth of literature that describes the ethnic traits of each nose, with a particular emphasis on the Brazilian nose, and talks about the major surgical approaches that can be applied in these situations. The low dorsum, broad nasal bones, thick skin, and bulbous tip are the primary features of the Brazilian nose. Many times, lateral osteotomies, root grafting, isotretinoin treatment for skin thickness, and neodomus formation are required. The Brazilian nose presents a surgical challenge that calls for the mastery of multiple procedures, not simply structured rhinoplasty. In certain cases, preservation rhinoplasty may even be used. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

A Comprehensive Review on the Total Synthesis of Antibacterial Furanomycin and Its Analogs

l-(+)-Furanomycin 1 is a miniature antibacterial natural product that contains an α-amino acid core. This non-proteinogenic α-amino acid was first isolated in 1967 by Katagiri and co-workers from the fermentation broth of Streptomyces threomyceticus L-803 (ATCC 15795). It is a substrate of isoleucyl aminoacyl-tRNA synthetase that replaces isoleucine in the protein translation process and exhibits antibacterial properties in vitro. It effectively acts as an antibacterial agent against M. tuberculosis, E. coli, B. subtilis, and some Shigella and Salmonella bacterial species at concentrations as low as the micromolar range. Consequently, synthetic chemists have garnered considerable interest from their specific structure–activity profile, distinctive chemical compositions, and distinct biological profile. This review comprehensively describes cutting-edge synthetic methodologies for synthesizing furanomycin and its analogs reported to date. Therefore, this review will offer an initial perspective on synthesizing furanomycin and its customized compounds.

Deep mantle plumes feeding periodic alignments of asthenospheric fingers beneath the central and southern Atlantic Ocean

High-resolution full waveform seismic tomography of the Earth's mantle beneath the south and central Atlantic Ocean brings into focus a series of asthenospheric low shear velocity channels, or "fingers" on both sides of the southern and central mid-Atlantic ridge (MAR), elongated in the direction of absolute plate motion with a spacing of [Formula: see text]1,800 to 2,000 km, and associated with bands of shallower residual seafloor depth anomalies that suggest channeled flow over thousands of kilometers. Each of the three most clearly resolved fingers on the African side of the MAR corresponds to a separate group of whole mantle plumes rooted in distinct patches at the core-mantle boundary, feeding hotspots, and volcanic lines with distinct isotopic signatures. Plumes of a given group appear to merge at the top of the lower mantle before separating again, suggesting interaction of deep mantle flow with a more vigorous mesoscale circulation in the upper mantle. The corresponding hotspots are generally offset from the location of the deep mantle plume roots. The distinct isotopic signatures of these hotspot groups are also detected in the mid-ocean ridge basalts at the location where the fingers meet the ridge. Meanwhile, at least some of the variability within each plume group could originate in the upper mantle and extended transition zone where plumes in a given group appear to merge and pond. This study also adds to mounting evidence that the African large low shear velocity province is not a uniform, unbroken pile of dense material rising high above the core-mantle boundary, but rather a collection of mantle plumes rooted in patches of distinct composition.

Coordination of force-generating actin-based modules stabilizes and remodels membranes in vivo.

Membrane remodeling drives a broad spectrum of cellular functions, and it is regulated through mechanical forces exerted on the membrane by cytoplasmic complexes. Here, we investigate how actin filaments dynamically tune their structure to control the active transfer of membranes between cellular compartments with distinct compositions and biophysical properties. Using intravital subcellular microscopy in live rodents we show that a lattice composed of linear filaments stabilizes the granule membrane after fusion with the plasma membrane and a network of branched filaments linked to the membranes by Ezrin, a regulator of membrane tension, initiates and drives to completion the integration step. Our results highlight how the actin cytoskeleton tunes its structure to adapt to dynamic changes in the biophysical properties of membranes.

Phytochemical Diversity and Biological Effects of Juniperus Thurifera L., Essential Oil : A Comparative Study using In Vitro and In Silico Methods.

Juniperus thurifera L., a plant endemic to the Moroccan High Atlas Mountains, thrives in extreme climatic conditions, resulting in the production of valuable secondary metabolites. This study aims to elucidate the phytochemical diversity and biological activities of J. thurifera essential oil (JTEO) through a comparative analysis of samples from two distinct regions: Tensift-Al Haouz and Azilal, using both in vitro and in silico methods. Gas Chromatography-Mass Spectrometry (GC-MS) analysis revealed 21 components in the Tensift-Al Haouz JTEO (99.99 % of the oil) and 23 components in the Azilal JTEO (99.58 % of the oil), with oxygenated monoterpenes being the predominant compounds in both. The biological activities were assessed in vitro. Antioxidant properties, evaluated using DPPH, FRAP, and ABTS assays, showed significant activity in both oils. Antibacterial activity was tested against two strains of Gram-positive and two strains of Gram-negative bacteria, with both oils demonstrating notable bacterial growth inhibition. Enzymatic assays assessed the antidiabetic (α-amylase and α-glucosidase), dermo-protective (tyrosinase and elastase), and neuroprotective (AChE and BChE) activities. Both oils displayed substantial inhibitory effects across all tested activities, with variations attributed to their distinct chemical compositions. In silico analyses of six target enzymes confirmed significant binding affinities of the major compounds. Notably, 2,2'-Thiobis(6-tert-butyl-p-cresol) exhibited strong binding affinities with AChE, BChE, α-amylase, α-glucosidase, tyrosinase, and elastase, with binding energies ranging from -10.0 to -6.2 kcal/mol. These findings indicate that JTEO is a rich source of bioactive compounds with promising potential in pharmacological and cosmetic applications.

O estabelecimento da Tipografia Hennies Irmãos em São Paulo: um estudo de caso pela perspectiva historiográfica

This article reviews historiographical methods applied to typography in Brazil, as well as more recent literature on graphic memory and microhistory as part of historiography. Intending to elucidate the history of the Hennies Brothers Letterpress Printing Shop in São Paulo this research, whose methodology cross-references different data sources and reduces the scale of observation, focused on the shop’s foundational years and the social relations through which it became part of the São Paulo letterpress printing sphere. These relations reveal, through printed materials and documents, an intense contact with immigrant communities that settled in São Paulo, distinct corporate compositions, typographers skilled in several languages, international contacts with graphic material suppliers and type foundries. The resulting narrative, which addresses the early trajectory of the Hennies Brothers—between 1891 and 1899—, was used as a case study to demonstrate methodological procedures as possibilities for revealingdeeper aspects in historical research, contributing to a reflection on historiographical work in typography.

Matrix Corrected SIMS In Situ Oxygen Isotope Analyses of Marine Shell Aragonite for High Resolution Seawater Temperature Reconstructions

AbstractMarine shells incorporate oxygen isotope signatures during growth, creating valuable records of seawater temperature and marine oxygen isotopic compositions. Secondary ion mass spectrometry (SIMS) measures these compositions in situ at finer length‐scales than traditional stable isotope analyses. However, determining oxygen isotope ratios in aragonite, the most common shell mineral, is hampered by a lack of ideal reference materials, limiting the accuracy of SIMS‐based seawater temperature reconstructions. Here, we tested the capability of SIMS to produce seawater temperature reconstructions despite the matrix calibration challenges associated with aragonite. We cultured Anadara trapezia bivalves at four controlled seawater temperatures (13–28°C) and used strontium labeling to mark the start of the temperature‐controlled shell increment, allowing for more spatially precise SIMS analysis. An improved matrix calibration was developed to ensure more accurate bio‐aragonite analyses that addressed matrix differences between the pure abiotic reference materials and the bio‐aragonite samples with intricate mineral‐organic architectures and distinct minor and trace element compositions. We regressed SIMS‐IRMS biases of abiotic and biogenic aragonites that account for their systematic differences in major, minor, and trace elements, allowing for more accurate SIMS analyses of the temperature‐controlled shell increment. The thorough matrix calibration allowed us to provide a SIMS‐based seawater‐corrected oxygen isotope thermometer of T(°C) = 23.05 ± 0.36 − 4.48 · (δ18Oaragonite [‰ VPDB] − δ18Oseawater [‰ VSMOW] ± 0.25) and 103lnαaragonite‐seawater = (17.78 ± 0.88) · 103/T (K) − (29.44 ± 2.40) that agrees with existing aragonitic IRMS‐based thermometer relationships and improves the applicability of SIMS‐based paleo‐environmental reconstructions of marine bio‐aragonites.

Preliminary Assessment of Morphology and Elemental Composition of Fine Particulates in Selected Urban Areas of Java Island

Rapid urbanization and high population density in three major cities in Indonesia, Bandung, Jakarta, and Tangerang have led to significant air quality issues. Fine inhalable particles (PM2.5) with distinct morphologies and elemental compositions pose considerable health risks. This study evaluates the morphology and chemical composition of PM2.5 in these urban areas on Java Island. PM2.5 samples were collected for 24-hour periods using a Teflon filter with the Super Speciation-Air Sampling System (SuperSASS) following the EPA sampling schedule, from May to September 2022. The Teflon sample with the highest PM2.5 concentration, representative of both weekdays and weekends, was selected for morphological analysis using Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX) and elemental characterization using Energy-Dispersive X-ray Fluorescence (ED-XRF) Epsilon. SEM images revealed distinct morphological characteristics at each site. In Bandung, particles were irregularly shaped, agglomerated, and flaky, with sizes ranging from 1.1-1.6 µm on weekdays and 0.9-1.3 µm on weekends. Jakarta has particles with semi-crystalline, tabular, elongated, and puff-like morphology, with sizes predominantly from 0.5-0.8 µm on weekdays and 0.9-1.3 µm weekends. In Tangerang, particles were irregularly faceted and agglomerated, with sizes between 0.5-1.3 µm on weekdays and 0.9-1.4 µm on weekends. Teflon-derived minerals (C,F) were present across all sites. EDX spectra revealed Ca-rich particles in Bandung, while S-rich particles were observed in Jakarta and Tangerang. XRF analysis further proved the major and minor elements, reflecting local pollution sources. The combined use of SEM-EDX and XRF offers a comprehensive profile of PM2.5, highlighting specific pollution sources in each city.

Extraction of mucilage polysaccharides from chia seed by hydrophobic deep eutectic solvents-based three-phase partitioning system: A phase behavior-driven approach

By incorporating the hydrophobic deep eutectic solvents (DESs) into the three-phase partitioning (TPP) technique, a TPP-based method was developed to extract the chia seed polysaccharide (CSP) from chia seed. Through a single-factor experiment and response-surface model, the optimal condition for the TPP extraction was determined as DES composed of dodecanoic acid and octanoic acid in a 1:1 M ratio, (NH4)2SO4 concentration of 32.86 %, crude extract–DES ratio of 0.93 (v/v), aqueous phase pH of 4.38, extraction temperature of 35 °C, and extraction time of 10 min. The polysaccharide yield of the constructed TPP method is 8.65 %, which is higher than the conventional water extraction method (yield is 6.96 %). Molecular dynamics simulations reveal the phase behavior of proteins and polysaccharides in the TPP system, showing that noncovalent interactions play a crucial role in the TPP system. The CSP obtained by the TPP method exhibits distinctive composition, structural, physicochemical, and functional properties, leading to improved thermal stability, rheological behavior, and antioxidant performance. Compared with the traditional extraction method, efficient extraction of CSP can be achieved flexibly using the proposed TPP approach, resulting in high yield and quality of CSP, which provides a new path for the large-scale utilization of chia seed.

Dysbiosis and interactions of the salivary bacteriome in obese individuals: A human cross-sectional study.

The prevalence of obesity is continually rising worldwide, posing a risk for the development of various serious diseases. The pathogenesis of obesity is complex and recent research suggests a link between obesity and the oral microbiome, though the specific mechanisms remain unclear. We collected saliva samples from 9 non-obese and 13 obese participants and conducted 16S rRNA sequencing to analyze the differences in oral microbiota between obese and non-obese individuals in terms of microbial abundance, functionality, and interaction networks. Obese participants exhibited a distinct composition of salivary microbiota compared to non-obese participants, with a greater number of ASVs detected and higher α diversity indices. Specifically, Haemophilus, Aggregatibacter, and Actinobacillus were significantly enriched, while Actinomyces showed significant depletion. Functional prediction analysis indicated that biofilm formation pathways were significantly more abundant in the obese group. Random forest regression model analysis identified Bergeyella as the most contributive genus, and interaction network analysis suggested that Bergeyella may function as a bridge node, linking the obese group-enriched genera to the broader microbial community and facilitating the exchange of information and resources. Our study suggests that obesity may be closely associated with salivary microbiota dysbiosis and functional changes. Further research is needed to elucidate the causal relationship and underlying molecular mechanisms between obesity and oral microbiota dysbiosis, or to determine if they mutually influence each other.

The Pax transcription factor EGL-38 links EGFR signaling to assembly of a cell-type specific apical extracellular matrix in the Caenorhabditis elegans vulva

The surface of epithelial tissues is covered by an apical extracellular matrix (aECM). The aECMs of different tissues have distinct compositions to serve distinct functions, yet how a particular cell type assembles the proper aECM is not well understood. We used the cell-type specific matrix of the C. elegans vulva to investigate the connection between cell identity and matrix assembly. The vulva is an epithelial tube composed of seven cell types descending from EGFR/Ras-dependent (1˚) and Notch-dependent (2˚) lineages. Vulva aECM contains multiple Zona Pellucida domain (ZP) proteins, which are a common component of aECMs across life. ZP proteins LET-653 and CUTL-18 assemble on 1˚ cell surfaces, while NOAH-1 assembles on a subset of 2˚ surfaces. All three ZP genes are broadly transcribed, indicating that cell-type specific ZP assembly must be determined by features of the destination cell surface. The paired box (Pax) transcription factor EGL-38 promotes assembly of 1˚ matrix and prevents inappropriate assembly of 2˚ matrix, suggesting that EGL-38 promotes expression of one or more ZP matrix organizers. Our results connect the known signaling pathways and various downstream effectors to EGL-38/Pax expression and the ZP matrix component of vulva cell fate execution. We propose that dedicated transcriptional networks may contribute to cell-appropriate assembly of aECM in many epithelial organs.

Legionella community dynamics in a drinking water distribution system: Impact of residual chlorine depletion

This study investigated the occurrence of Legionella spp. in a chlorinated drinking water distribution system (DWDS), focusing on their community compositions and association with physicochemical water quality. Water samples were collected throughout the DWDS, covering from the treated water reservoir to distal ends. Although Legionella spp. genes were not detected at the reservoir, their abundance dramatically increased along the distribution network, reaching up to 4.4 log copies/L at distal sites. The Legionella communities were further characterized by high-throughput amplicon sequencing targeting the genus-specific 16S rRNA gene. The results revealed a diverse Legionella community, including amplicon sequence variants with high similarity (> 99 %) to potentially pathogenic species such as L. drozanskii and L. pneumophila, albeit at low levels. Moreover, Legionella community diversity increased significantly along the distribution system, leading to distinct community compositions at distal sites. Importantly, decay of residual chlorine concentration was identified as a key factor both in increasing the Legionella gene levels and shaping the community structure. Overall, this study underscores the importance of preventing pipe corrosion and maintaining adequate disinfectant residuals to minimize Legionella regrowth in DWDS.

Divergence and convergence in epiphytic and endophytic phyllosphere bacterial communities of rice landraces.

Phyllosphere-associated microbes can significantly alter host plant fitness, with distinct functions provided by bacteria inhabiting the epiphytic (external surface) vs endophytic niches (internal leaf tissue). Hence, it is important to understand the assembly and stability of these phyllosphere communities, especially in field conditions. Broadly, epiphytic communities should encounter more environmental fluctuations and frequent immigration, whereas endophytic microbiota should face stronger host selection. As a result, we expect greater variability in epiphytic than endophytic communities. We analyzed the structure and stability of leaf phyllosphere microbiota of four traditionally cultivated rice landraces and one commercial variety from northeast India grown in the field for 3 consecutive years, supplemented with opportunistic sampling of eight other landraces. Epiphytic and endophytic bacterial communities shared dominant core genera such as Methylobacterium and Sphingomonas. Consistent with an overall strong environmental effect, both communities varied more across sampling years than across host landraces. Seeds sampled from a focal landrace did not support vertical transmission of phyllosphere bacteria, suggesting that both types of communities are assembled anew each generation. Despite these points of convergence, epiphytic communities had distinct composition and significantly higher microbial load and were more rich, diverse, modular, and unstable than endophytic communities. Finally, focused sampling of one landrace across developmental stages showed that the divergence between the two types of communities arose primarily at the flowering stage. Thus, our results show both convergent and divergent patterns of community assembly and composition in distinct phyllosphere niches in rice, identifying key bacterial genera and host developmental stages that may aid agricultural interventions to increase rice yield.IMPORTANCEPhyllosphere (leaf-associated) microbes significantly impact plant fitness, making it crucial to understand how these communities are assembled and maintained. While many studies have analyzed epiphytic (surface) phyllosphere communities, we have a relatively poor understanding of endophytic communities which colonize the very distinct niche formed inside leaf tissues. We found that across several rice landraces, both communities are largely colonized by the same core genera, indicating divergence at the species level across the two leaf niches and highlighting the need to understand the mechanisms underlying this divergence. Surprisingly, both epiphytic and endophytic communities were only weakly shaped by the host landrace, with a much greater role for environmental factors that likely vary over time. Thus, microbiome-based agricultural interventions for increasing productivity could perhaps be generalized across rice varieties but would need to account for the temporal instability of the microbiota. Our results thus highlight the importance of data sets such as ours-with extensive sampling across landraces and years-for understanding phyllosphere microbiota and their applications in the field.