Mucus Composition Research Articles

Surface Metabolite Amino Acids and Collagen Profiling in Refrigerated Tilapia Fish (Oreochromis niloticus): Implications for Identification and Quality Assessment

Nile tilapia (Oreochromis niloticus) by-products, including the scales, skin, and mucus, are rich sources of protein with a balanced amino acid profile and high collagen content. Cold storage at 4 ℃ is commonly used to maintain the freshness of tilapia fish in retail settings. This study aims to investigate the changes in surface metabolites and collagen content in tilapia fish during cold storage at 4 ℃. Fresh tilapia fish was stored at 4 ℃ for 7 days to monitor physicochemical and metabolite changes. Fish collagen content was extracted using acetic acid and pepsin, pH values were measured using a calibrated pH meter, protein content was determined via the Bradford method, and creatine and phenylalanine levels were assessed using High-Performance Liquid Chromatography (HPLC). Analysis was conducted on days 0, 3, and 7 of cold storage. Significant reductions (p<0.05) in collagen content from fish scales were observed on the 3rd day of storage, declining from 72.60 ± 12.40% to 30.17 ± 17.62%. pH levels of fish scales and mucus showed a slight alkaline shift, while the skin turned acidic due to bacterial and enzymatic activities. Protein content in the scales, skin, and mucus showed a substantial loss exceeding 50% after 7 days of cold storage. Changes in creatine and phenylalanine concentrations in the mucus further indicated a decline in tilapia fish freshness due to biochemical reactions post-mortem, compromising overall quality. In conclusion, the duration of cold storage significantly affects the composition of tilapia fish scales, skin, and mucus, with a 7-day storage period identified as a suitable freshness indicator in compliance with FDA guidelines permitting fresh fish to be stored at 4 °C for up to two days.

Human milk oligosaccharide 2’-fucosyllactose protects against high-fat diet-induced obesity by changing intestinal mucus production, composition and degradation linked to changes in gut microbiota and faecal proteome profiles in mice

ObjectiveTo decipher the mechanisms by which the major human milk oligosaccharide (HMO), 2’-fucosyllactose (2’FL), can affect body weight and fat mass gain on high-fat diet (HFD) feeding in mice. We...

Planarian Mucus: A Novel Source of Pleiotropic Cytotoxic and Cytostatic Agents against Cancer Cells.

Biological evolution has generated a vast array of natural compounds produced by organisms across all domains. Among these, secondary metabolites, selected to enhance an organism's competitiveness in its natural environment, make them a reservoir for discovering new compounds with cytotoxic activity, potentially useful as novel anticancer agents. Slime secretions, the first barrier between epithelial surfaces and the surrounding environment, frequently contain cytotoxic molecules to limit the growth of parasitic organisms. Planarians, freshwater Triclads, continuously secrete a viscous mucus with multiple physiological functions. The chemical composition of planarian mucus has been only partially elucidated, and there are no studies reporting its cytotoxic or cytostatic effects. In this study, we developed a protocol for collecting mucus from Dugesia japonica specimens and we demonstrated that it inhibits the growth of cancer cells by activating cytostatic and ROS-dependent cytotoxic mechanisms inducing lipid droplet accumulation and mitochondrial membrane reorganization. Although further research is needed to identify the specific chemicals responsible for the anticancer activity of planarian mucus, this work opens up numerous research avenues aimed at better understanding the mechanisms of action of this product for potential therapeutic applications.

Analysis of Neuropeptides in the Intestinal Mucus of Patients with Ulcerative Colitis Using RNA Sequencing

Introduction: Inflammation in ulcerative colitis (UC) originates in the colorectal mucosa. Transcriptome sequencing analysis of the colorectal mucosa allows the identification of potential neuropeptides related to local neurotransmission. The intestinal mucus lining the surface of the mucosa may harbor biomarkers of mucosal inflammation; however, this has not been sufficiently investigated, given the difficulty in obtaining human samples. We previously reported the feasibility of obtaining mucin samples for proteomic analysis by brushing during colonoscopy. Herein, we aimed to investigate the composition of the intestinal mucus and detect neuropeptides characteristic of UC. Methods: Mucus and mucosal samples were collected from patients with UC from the colorectum in areas showing remission or active UC using a brush catheter and biopsy forceps during colonoscopy. RNA sequencing findings of mucus samples of active and remission areas were compared. RNA and protein expression levels of significantly upregulated neuropeptides were analyzed. Results: Of the neuropeptides associated with UC, somatostatin (SST) was significantly elevated in areas of remission, according to RNA sequencing results of mucus and expression levels in mucus RNA and proteins. Conversely, SST expression in the mucosa was increased in the inflamed areas. Flow cytometry revealed that the fluorescence intensity of SST-positive cells in the remission zone was higher in the mucus than in the mucosa. Conclusion: SST expression in the mucus is considered to be an important factor associated with UC activity.

Prediction on Air-Nasal Mucus Partition Coefficients of Odor Compounds.

The air-nasal mucus partition coefficient is a crucial property among all of the interaction mechanisms between odor molecules and olfactory receptors, since this property contributes to our sense of smell. Due to the complexity of the mucus composition, in vivo determination of the air-mucus partition coefficient is a technical challenge. A predictable model of the air-mucus partition coefficient can provide valuable insights into the chemical properties that govern olfactory perception and can help design desired odorants. In this study, we propose a novel model based on the deep-layer neural network (DNN) algorithm to predict the air-mucus partition coefficients for a range of odor compounds. The molecular surface charge density (σ-profile) calculated from the COnductor like Screening MOdel for Real Solvents (COSMO-RS) thermodynamic package was adapted as descriptors of structural features of odor molecules. The results revealed that the air-mucus partition coefficients are highly correlated to the σ-profile of the studied compounds. The information obtained from the study provided interpretable results, which not only help in identifying the molecular features that contribute to the air-mucus partition coefficient of odorants but also aid in the design of compounds with the desired odor properties.

Mucus carbohydrate composition correlates with scleractinian coral phylogeny

The mucus surface layer serves vital functions for scleractinian corals and consists mainly of carbohydrates. Its carbohydrate composition has been suggested to be influenced by environmental conditions (e.g., temperature, nutrients) and microbial pressures (e.g., microbial degradation, microbial coral symbionts), yet to what extend the coral mucus composition is determined by phylogeny remains to be tested. To investigate the variation of mucus carbohydrate compositions among coral species, we analyzed the composition of mucosal carbohydrate building blocks (i.e., monosaccharides) for five species of scleractinian corals, supplemented with previously reported data, to discern overall patterns using cluster analysis. Monosaccharide composition from a total of 23 species (belonging to 14 genera and 11 families) revealed significant differences between two phylogenetic clades that diverged early in the evolutionary history of scleractinian corals (i.e., complex and robust; p = 0.001, R2 = 0.20), mainly driven by the absence of arabinose in the robust clade. Despite considerable differences in environmental conditions and sample analysis protocols applied, coral phylogeny significantly correlated with monosaccharide composition (Mantel test: p < 0.001, R2 = 0.70). These results suggest that coral mucus carbohydrates display phylogenetic dependence and support their essential role in the functioning of corals.

P209 Mucus composition and interactions with Pseudomonas aeruginosa in chronically infected cystic fibrosis and primary ciliary dyskinesia patients

P209 Mucus composition and interactions with Pseudomonas aeruginosa in chronically infected cystic fibrosis and primary ciliary dyskinesia patients

Mucus production, host-microbiome interactions, hormone sensitivity, and innate immune responses modeled in human cervix chips

Modulation of the cervix by steroid hormones and commensal microbiome play a central role in the health of the female reproductive tract. Here we describe organ-on-a-chip (Organ Chip) models that recreate the human cervical epithelial-stromal interface with a functional epithelial barrier and production of mucus with biochemical and hormone-responsive properties similar to living cervix. When Cervix Chips are populated with optimal healthy versus dysbiotic microbial communities (dominated by Lactobacillus crispatus and Gardnerella vaginalis, respectively), significant differences in tissue innate immune responses, barrier function, cell viability, proteome, and mucus composition are observed that are similar to those seen in vivo. Thus, human Cervix Organ Chips represent physiologically relevant in vitro models to study cervix physiology and host-microbiome interactions, and hence may be used as a preclinical testbed for development of therapeutic interventions to enhance women’s health.

The spatial distribution of CFTR-rich Ionocytes cells in the postnatal mouse airway development

Ionocytes are a new type of rare airway epithelial cells expressing Ascl3 and Foxi1 transcription factors, as well as 50% of Cftr-transcripts in mouse airways. However, their role and precise location remain mostly unexplored. This research aimed to shed light on ionocyte ontogeny and distribution within the mouse airway epithelium. Mice were bred in the C57Bl6/J background and maintained in the Specific Pathogen Free mouse facility of Centro de Estudios Científicos (CECs) with access to food and water ad libitum. We used 1,7, 10, 14,21 and 28-days-old wild-type mice, 6 and 8-week-old, and 1 year wild-type and 14-days-old 6 and 8-week-old CftrΔF508/ΔF508 animals. The tracheas were sliced in frontal sections, and the ionocytes were identified by immunofluorescence against the FOXI1 transcription factor. All values were expressed as mean ± S.E.M. All animal procedures were approved by the institutional IACUC (CECS-2022-03). We found that FOXI1+cells had a triangular shape with a basolateral process. Unexpectedly, we observed that FOXI1+cells appear postnatally close to the submucosal glands (SMG), and its number increases drastically between 6 and 8-week-old wild type mice. The quantity of FOXI1+cells cells in the adult trachea decreased towards the distal part (proximal=11.2±1.2 vs distal=4.0±0.9 FOXI1+cells/mm basal lamina, n=7, P=&lt;0,001, t-test), and we did not find significative differences between WT and CftrΔF508/ΔF508 adult mouse. FOXI1+cells were often observed in the epithelia around the collecting duct exit and in the collecting duct epithelium of the SMG. In conclusion, our study provides new insights into the localization and distribution of ionocytes in the mouse airway epithelium. Our results indicate that ionocytes may play a role in regulating mucus composition in upper airways. We suggest that age-dependent changes in cell quantity might reflect the need of increased CFTR function in adult stages. Further research is needed to fully understand the function of ionocytes in the airway and their potential role in respiratory diseases such as cystic fibrosis. Proyecto Postdoctoral 3220672 Proyecto FONDECYT 1221257. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Rab7-dependent regulation of goblet cell protein CLCA1 modulates gastrointestinal homeostasis

Inflammation in ulcerative colitis is typically restricted to the mucosal layer of distal gut. Disrupted mucus barrier, coupled with microbial dysbiosis, has been reported to occur prior to the onset of inflammation. Here, we show the involvement of vesicular trafficking protein Rab7 in regulating the colonic mucus system. We identified a lowered Rab7 expression in goblet cells of colon during human and murine colitis. In vivo Rab7 knocked down mice (Rab7KD) displayed a compromised mucus layer, increased microbial permeability, and depleted gut microbiota with enhanced susceptibility to dextran sodium-sulfate induced colitis. These abnormalities emerged owing to altered mucus composition, as revealed by mucus proteomics, with increased expression of mucin protease chloride channel accessory 1 (CLCA1). Mechanistically, Rab7 maintained optimal CLCA1 levels by controlling its lysosomal degradation, a process that was dysregulated during colitis. Overall, our work establishes a role for Rab7-dependent control of CLCA1 secretion required for maintaining mucosal homeostasis.

Rab7-dependent regulation of goblet cell protein CLCA1 modulates gastrointestinal homeostasis.

Inflammation in ulcerative colitis is typically restricted to the mucosal layer of distal gut. Disrupted mucus barrier, coupled with microbial dysbiosis, has been reported to occur prior to the onset of inflammation. Here, we show the involvement of vesicular trafficking protein Rab7 in regulating the colonic mucus system. We identified a lowered Rab7 expression in goblet cells of colon during human and murine colitis. In vivo Rab7 knocked down mice (Rab7KD) displayed a compromised mucus layer, increased microbial permeability, and depleted gut microbiota with enhanced susceptibility to dextran sodium-sulfate induced colitis. These abnormalities emerged owing to altered mucus composition, as revealed by mucus proteomics, with increased expression of mucin protease chloride channel accessory 1 (CLCA1). Mechanistically, Rab7 maintained optimal CLCA1 levels by controlling its lysosomal degradation, a process that was dysregulated during colitis. Overall, our work establishes a role for Rab7-dependent control of CLCA1 secretion required for maintaining mucosal homeostasis.

Characterizing interregional differences in the rheological properties and composition of rat small intestinal mucus.

The mucus layer in the small intestine is generally regarded as a barrier to drug absorption. However, the mucus layer is a complex system, and presently, only a few studies have been conducted to elucidate its physicochemical properties. The current study hypothesizes that the mucus layer contains solubility-enhancing surfactants and thus might aid the oral absorption of poorly water-soluble drugs.Mucus was sampled from sections of the small intestine of fasted rats to analyze the rheological properties and determine the mucus pH and concentrations of proteins and endogenous surfactants, i.e., bile salts, polar lipids, and neutral lipids.The mucus layer in the two proximal sections of the small intestine exhibited different rheological properties such as higher zero-shear viscosity and lower loss tangent and higher protein concentrations compared to all subsequent sections of the small intestine. The pH of the mucus layer was stable at ~ 6.5 throughout most of the small intestine, but increased to 7.5 in the ileum.The bile salt concentrations increased from the duodenum (16.0 ± 2.2mM) until the mid jejunum (55.1 ± 9.5mM), whereas the concentrations of polar lipids and neutral lipids decreased from the duodenum (17.4 ± 2.2mM and 37.8 ± 1.6mM, respectively) until the ileum (4.8 ± 0.4mM and 10.7 ± 1.1mM, respectively).In conclusion, the mucus layer of the rat small intestine contains endogenous surfactants at levels that might benefit solubilization and absorption of orally administered poorly water-soluble drugs.

Aluminum exposure alters the pedal mucous secretions of the chocolate-band snail, Eobania vermiculata (Gastropoda: Helicidae).

Aluminum (Al) is used in everyday life and present in food drugs, packaging, industry, and agriculture. Although it is the most common metal in the Earth crust, a correlation has been demonstrated between its presence and various pathologies, even serious ones, especially of a neurological type. However, there is a histological gap regarding the role Al can have in contact with the covering and secreting epithelia. The alterations of the ventral and dorsal foot mucocytes and their secretions of the snail Eobania vermiculata caused by Al were investigated in situ by histochemical and lectin-histochemical techniques. Administration to different experimental groups took place for 3 and 9 days with 50 and 200 μM of AlCl3. Several types of mucocytes were detected with a prevalent secretion of acid glycans in the foot of E. vermiculata. Sulfated glycans prevail in the dorsal region, with one type showing only fucosylated residues and another also having galactosaminylated and glycosaminylated residues. Carboxylated glycans prevail in the ventral region, with presence of galactosaminylated, glycosaminylated, and fucosylated residuals in both cells. Snails treated presented a general decrease of mucin amount in the secreting cells and affected the mucus composition. These changes could alter the rheological and functional properties of the mucus with possible implications for the health of the treated animals. RESEARCH HIGHLIGHTS: Snails were fed with Al-contaminated lettuce at different concentrations. In the foot mucocytes produced mucus with prevailing acidic glycans. In the treated resulted a reduction in the amount of mucus and an alteration of glycan composition.

Mucus Structure, Viscoelastic Properties, and Composition in Chronic Respiratory Diseases.

The respiratory mucus, a viscoelastic gel, effectuates a primary line of the airway defense when operated by the mucociliary clearance. In chronic respiratory diseases (CRDs), such as asthma, chronic obstructive pulmonary disease (COPD), and cystic fibrosis (CF), the mucus is overproduced and its solid content augments, changing its structure and viscoelastic properties and determining a derangement of essential defense mechanisms against opportunistic microbial (virus and bacteria) pathogens. This ensues in damaging of the airways, leading to a vicious cycle of obstruction and infection responsible for the harsh clinical evolution of these CRDs. Here, we review the essential features of normal and pathological mucus (i.e., sputum in CF, COPD, and asthma), i.e., mucin content, structure (mesh size), micro/macro-rheology, pH, and osmotic pressure, ending with the awareness that sputum biomarkers (mucins, inflammatory proteins and peptides, and metabolites) might serve to indicate acute exacerbation and response to therapies. There are some indications that old and novel treatments may change the structure, viscoelastic properties, and biomarker content of sputum; however, a wealth of work is still needed to embrace these measures as correlates of disease severity in association with (or even as substitutes of) pulmonary functional tests.

SLE serum induces altered goblet cell differentiation and leakiness in human intestinal organoids

Human intestinal epithelial cells are the interface between luminal content and basally residing immune cells. They form a tight monolayer that constantly secretes mucus creating a multilayered protective barrier. Alterations in this barrier can lead to increased permeability which is common in systemic lupus erythematosus (SLE) patients. However, it remains unexplored how the barrier is affected. Here, we present an in vitro model specifically designed to examine the effects of SLE on epithelial cells. We utilize human colon organoids that are stimulated with serum from SLE patients. Combining transcriptomic with functional analyses revealed that SLE serum induced an expression profile marked by a reduction of goblet cell markers and changed mucus composition. In addition, organoids exhibited imbalanced cellular composition along with enhanced permeability, altered mitochondrial function, and an interferon gene signature. Similarly, transcriptomic analysis of SLE colon biopsies revealed a downregulation of secretory markers. Our work uncovers a crucial connection between SLE and intestinal homeostasis that might be promoted in vivo through the blood, offering insights into the causal connection of barrier dysfunction and autoimmune diseases.

The role of adenocarcinoma subtypes and immunohistochemistry in predicting lymph node metastasis in early invasive lung adenocarcinoma

BackgroundIdentifying lymph node metastasis areas during surgery for early invasive lung adenocarcinoma remains challenging. The aim of this study was to develop a nomogram mathematical model before the end of surgery for predicting lymph node metastasis in patients with early invasive lung adenocarcinoma.MethodsIn this study, we included patients with invasive lung adenocarcinoma measuring ≤ 2 cm who underwent pulmonary resection with definite pathology at Qilu Hospital of Shandong University from January 2020 to January 2022. Preoperative biomarker results, clinical features, and computed tomography characteristics were collected. The enrolled patients were randomized into a training cohort and a validation cohort in a 7:3 ratio. The training cohort was used to construct the predictive model, while the validation cohort was used to test the model independently. Univariate and multivariate logistic regression analyses were performed to identify independent risk factors. The prediction model and nomogram were established based on the independent risk factors. Recipient operating characteristic (ROC) curves were used to assess the discrimination ability of the model. Calibration capability was assessed using the Hosmer–Lemeshow test and calibration curves. The clinical utility of the nomogram was assessed using decision curve analysis (DCA).ResultsThe overall incidence of lymph node metastasis was 13.23% (61/461). Six indicators were finally determined to be independently associated with lymph node metastasis. These six indicators were: age (P < 0.001), serum amyloid (SA) (P = 0.008); carcinoma antigen 125 (CA125) (P = 0. 042); mucus composition (P = 0.003); novel aspartic proteinase of the pepsin family A (Napsin A) (P = 0.007); and cytokeratin 5/6 (CK5/6) (P = 0.042). The area under the ROC curve (AUC) was 0.843 (95% CI: 0.779–0.908) in the training cohort and 0.838 (95% CI: 0.748–0.927) in the validation cohort. the P-value of the Hosmer–Lemeshow test was 0.0613 in the training cohort and 0.8628 in the validation cohort. the bias of the training cohort corrected C-index was 0.8444 and the bias-corrected C-index for the validation cohort was 0.8375. demonstrating that the prediction model has good discriminative power and good calibration.ConclusionsThe column line graphs created showed excellent discrimination and calibration to predict lymph node status in patients with ≤ 2 cm invasive lung adenocarcinoma. In addition, the predictive model has predictive potential before the end of surgery and can inform clinical decision making.

P178 Changes in composition and structure of ileal mucus in Crohn’s disease patients compared to healthy controls

Abstract Background Crohn’s disease (CD) is a chronic transmural disease that can affect any part of the gastrointestinal tract. Typically, the terminal ileum is impacted. The pathogenesis of this disease results from a complicated interaction of multiple factors, with the intestinal barrier playing a critical role. The intestinal barrier in the ileum is comprised of epithelial cells that are coated with a mucus layer. This barrier is permeable to nutrient absorption and microbiota. Detailed analyses of human ileal mucus are currently absent. Our study aimed to comprehend the function of mucus and the biophysical and biochemical stimuli that exist in the mucus layer during ileal inflammation, in contrast to the healthy state. Methods We enrolled 28 patients diagnosed with Crohn’s disease (CD) and 27 healthy individuals as part of our study. Mucus and biopsies from the terminal ileum were collected during a colonoscopy. The extent of clinical, endoscopic and histologic inflammation in the terminal ileum at the time of collection was evaluated using the Harvey-Bradshaw Index, Simple Endoscopic Score, and modified Naini and Cortina score. The disease trajectory and dietary behaviors of all patients and healthy controls were documented. Samples were processed following protocols for various analyses, including rheology, proteomics and scanning electron microscopy (SEM). Results Our study presents the first data on the rheology and viscoelastic properties, of human ileal mucus. Interestingly, we discovered notable variations in the viscoelastic properties of mucus in CD patients compared to healthy individuals. Furthermore, the mucus mesh size and structure differed in CD patients in comparison to healthy controls. The SEM pictures also displayed these quantitative changes. We further assessed clinical characteristics, encompassing duration of disease, and observed certain variations, although their significance is not yet statistically established. A distinct profile was detected in CD patients compared to healthy controls using proteomic analysis. The ileal mucus of CD patients demonstrated elevated levels of ITGB2 and S100 proteins, which are involved in inflammatory pathways. Moreover, a correlation was found with histologic inflammation at the time of the collection. Conclusion In our study, significant changes in mucus composition and structure were found in the terminal ileum of CD patients, compared to healthy controls. This preliminary analysis provides a basis for further investigations to establish correlations between mucus composition and viscoelastic properties, and the subsequent effects on the underlying epithelial barrier.

Mechanical abrasion stimulation: Altered epidermal mucus composition and microbial community in grass carp (Ctenopharyngodon idella)

In modern high-density farming, seasonal change, fishing, transportation, and other conditions easily cause mechanical abrasion of fish skin. This leads to alterations in the material balance of the epidermal mucus composition of fish, preventing normal immune function. Subsequently, the risk of disease increases. In this study, grass carp (Ctenopharyngodon idella) was used as an object to investigate immune-related enzyme activities, structural characteristics, and physiological changes of its epidermal mucous cells caused by mechanical abrasion. Furthermore, we explored the changes in body surface mucus composition and microbial community diversity and structure. Our results showed that mechanical abrasion stimulation, significantly changed the activities of immune-related enzymes, such as lysozyme (LZM), alkaline phosphatase (AKP), and acid phosphatase (ACP) were within 24 h (P < 0.05). Their levels gradually recovered after 48 h. In contrast, no significant change was observed in superoxide dismutase (SOD) levels. The number of mucous cells increased, especially those of type I and type II mucous cells in the dorsal skin, which were significantly increased (P < 0.05). Meanwhile, the stimulation changed the metabolites composition of the fish epidermal mucus in the short term, upregulating 12-OPDA, indole, quinic acid and GSH, which are beneficial to antibacterial and anti-inflammatory, and downregulating L-saccharopine, L-2-aminoadipic acid, spermine, GSSG and ribose 5-phosphate, which disrupt protein synthesis, energy production and DNA synthesis. Additionally, these metabolite changes further affect the composition of microorganism communities, rising the abundance of certain disease-associated microorganisms, such as Acidovorax, Rhizobiaceae, Aurantimicrobium, and Leifsonia, which increases the risk of disease in fish. The findings of the present study provide a deeper understanding of the role of mucus as a component of the immune system in fish and provide a scientific basis for effective grass carp culture management and disease control.

Analysis, classification and identification of gastropod locomotive mucus by Fourier transform infrared spectroscopy

ABSTRACT Mucus is a defining feature of many gastropod phenotypes. Its material properties are a product of selection acting on the relationship between mucus composition, structure and performance; however, to date, there are very few studies addressing this. Here, we introduce attenuated total reflection Fourier transform infrared (FTIR) spectroscopy as an accessible analytical technique to record, identify and classify gastropod locomotive mucus, as deposited, with practically no intervention. Advancing the field beyond previous spectroscopic studies, we also probe mucus response to a temperature increase, determining its propensity to remain hydrated (i.e. resist denaturation) and serving as the basis for building cladograms based on spectral similarities. Specifically, the relative content of proteins, their secondary structures, protein-carbohydrate interactions, and thermal stability were investigated and shown to have significant variation between species. Collating and comparing over 648 spectra across 12 species and 7 superfamilies, we report that it is even possible to classify gastropods based solely on their secreted pedal mucus. This was further compared to previously published phylogenetic data and taxonomies enabling a 100% hit rate of genus assignment, implying that mucus FTIR may also be a powerful tool for field-based biodiversity studies.

Benzodiazepine Delorazepam Induces Locomotory Hyperactivity and Alterations in Pedal Mucus Texture in the Freshwater Gastropod Planorbarius corneus

Benzodiazepines, psychotropic drugs, are ubiquitous in the aquatic environment due to over-consumption and inefficient removal by sewage treatment plants. Bioaccumulation with consequent behavioral and physiological effects has been reported in many aquatic species. However, the responses are species-specific and still poorly understood. To improve the knowledge, we exposed the freshwater snail Planorbarius corneus to 1, 5, or 10 µg/L of delorazepam, the most widely consumed benzodiazepine in Italy. Conventional behavioral tests were used to assess the effects on locomotor and feeding behavior. Histological and biochemical analyses were also performed to detect possible changes in the structure and composition of the foot mucus and glands. The results show a paradoxical response with reduced feeding activity and locomotor hyperactivity. Pedal mucus was altered in texture but not in composition, becoming particularly rich in fibrous collagen-like material, and a significant change in the protein composition was highlighted in the foot. In conclusion, exposure to delorazepam induces disinhibited behavior in Planorbarius corneus, potentially increasing the risk of predation, and an increase in mucus protein production, which, together with reduced feeding activity, would severely compromise energy resources.