Nociceptor neurons direct goblet cells via a CGRP-RAMP1 axis to drive mucus production and gut barrier protection.

Neuroepithelial crosstalk is critical for gut physiology. However, the mechanisms by which sensory neurons communicate with epithelial cells to mediate gut barrier protection at homeostasis and during inflammation are not well understood. Here, we find that Nav1.8+CGRP+ nociceptor neurons are juxtaposed with and signal to intestinal goblet cells to drive mucus secretion and gut protection. Nociceptor ablation led to decreased mucus thickness and dysbiosis, while chemogenetic nociceptor activation or capsaicin treatment induced mucus growth. Mouse and human goblet cells expressed Ramp1, receptor for the neuropeptide CGRP. Nociceptors signal via the CGRP-Ramp1 pathway to induce rapid goblet cell emptying and mucus secretion. Notably, commensal microbes activated nociceptors to control homeostatic CGRP release. In the absence of nociceptors or epithelial Ramp1, mice showed increased epithelial stress and susceptibility to colitis. Conversely, CGRP administration protected nociceptor-ablated mice against colitis. Our findings demonstrate a neuron-goblet cell axis that orchestrates gut mucosal barrier protection.

Potential roles of gut microbiome and metabolites in modulating ALS in mice.

Amyotrophic lateral sclerosis (ALS) is a complex neurodegenerative disorder, in which the clinical manifestations may be influenced by genetic and unknown environmental factors. Here we show that ALS-prone Sod1 transgenic (Sod1-Tg) mice have a pre-symptomatic, vivarium-dependent dysbiosis and altered metabolite configuration, coupled with an exacerbated disease under germ-free conditions or after treatment with broad-spectrum antibiotics. We correlate eleven distinct commensal bacteria at our vivarium with the severity of ALS in mice, and by their individual supplementation into antibiotic-treated Sod1-Tg mice we demonstrate that Akkermansia muciniphila (AM) ameliorates whereas Ruminococcus torques and Parabacteroides distasonis exacerbate the symptoms of ALS. Furthermore, Sod1-Tg mice that are administered AM are found to accumulate AM-associated nicotinamide in the central nervous system, and systemic supplementation of nicotinamide improves motor symptoms and gene expression patterns in the spinal cord of Sod1-Tg mice. In humans, we identify distinct microbiome and metabolite configurations-including reduced levels of nicotinamide systemically and in the cerebrospinal fluid-in a small preliminary study that compares patients with ALS with household controls. We suggest that environmentally driven microbiome-brain interactions may modulate ALS in mice, and we call for similar investigations in the human form of the disease.

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.

OBJECTIVE: To 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 wanted to elucidate whether 2'FL metabolic effects are linked with changes in intestinal mucus production and secretion, mucin glycosylation and degradation, as well as with the modulation of the gut microbiota, faecal proteome and endocannabinoid (eCB) system. RESULTS: 2'FL supplementation reduced HFD-induced obesity and glucose intolerance. These effects were accompanied by several changes in the intestinal mucus layer, including mucus production and composition, and gene expression of secreted and transmembrane mucins, glycosyltransferases and genes involved in mucus secretion. In addition, 2'FL increased bacterial glycosyl hydrolases involved in mucin glycan degradation. These changes were linked to a significant increase and predominance of bacterial genera Akkermansia and Bacteroides, different faecal proteome profile (with an upregulation of proteins involved in carbon, amino acids and fat metabolism and a downregulation of proteins involved in protein digestion and absorption) and, finally, to changes in the eCB system. We also investigated faecal proteomes from lean and obese humans and found similar changes observed comparing lean and obese mice. CONCLUSION: Our results show that the HMO 2'FL influences host metabolism by modulating the mucus layer, gut microbiota and eCB system and propose the mucus layer as a new potential target for the prevention of obesity and related disorders.

Appearance of hexahydrocannabinols as recreational drugs and implications for cannabis drug testing - focus on HHC, HHC-P, HHC-O and HHC-H.

This study investigated the effects of hexahydrocannabinol (HHC) and other unclassified cannabinoids, which were recently introduced to the recreational drug market, on cannabis drug testing in urine and oral fluid samples. After the appearance of HHC in Sweden in 2022, the number of posts about HHC on an online drug discussion forum increased significantly in the spring of 2023, indicating increased interest and use. In parallel, the frequency of false positive screening tests for tetrahydrocannabinol (THC) in oral fluid, and for its carboxy metabolite (THC-COOH) in urine, rose from <2% to >10%. This suggested that HHC cross-reacted with the antibodies in the immunoassay screening, which was confirmed in spiking experiments with HHC, HHC-COOH, HHC acetate (HHC-O), hexahydrocannabihexol (HHC-H), hexahydrocannabiphorol (HHC-P), and THC-P. When HHC and HHC-P were classified as narcotics in Sweden on 11 July 2023, they disappeared from the online and street shops market and were replaced by other unregulated variants (e.g. HHC-O and THC-P). In urine samples submitted for routine cannabis drug testing, HHC-COOH concentrations up to 205 (mean 60, median 27) µg/L were observed. To conclude, cannabis drug testing cannot rely on results from immunoassay screening, as it cannot distinguish between different tetra- and hexahydrocannabinols, some being classified but others unregulated. The current trend for increased use of unregulated cannabinols will likely increase the proportion of positive cannabis screening results that need to be confirmed with mass spectrometric methods. However, the observed cross-reactivity also means a way to pick up use of new cannabinoids that otherwise risk going undetected.

Cyanotoxin Occurrence and Diversity in 98 Cyanobacterial Blooms from Swedish Lakes and the Baltic Sea.

The Drinking Water Directive (EU) 2020/2184 includes the parameter microcystin LR, a cyanotoxin, which drinking water producers need to analyze if the water source has potential for cyanobacterial blooms. In light of the increasing occurrences of cyanobacterial blooms worldwide and given that more than 50 percent of the drinking water in Sweden is produced from surface water, both fresh and brackish, the need for improved knowledge about cyanotoxin occurrence and cyanobacterial diversity has increased. In this study, a total of 98 cyanobacterial blooms were sampled in 2016-2017 and identified based on their toxin production and taxonomical compositions. The surface water samples from freshwater lakes throughout Sweden including brackish water from eight east coast locations along the Baltic Sea were analyzed for their toxin content with LC-MS/MS and taxonomic composition with 16S rRNA amplicon sequencing. Both the extracellular and the total toxin content were analyzed. Microcystin's prevalence was highest with presence in 82% of blooms, of which as a free toxin in 39% of blooms. Saxitoxins were found in 36% of blooms in which the congener decarbamoylsaxitoxin (dcSTX) was detected for the first time in Swedish surface waters at four sampling sites. Anatoxins were most rarely detected, followed by cylindrospermopsin, which were found in 6% and 10% of samples, respectively. As expected, nodularin was detected in samples collected from the Baltic Sea only. The cyanobacterial operational taxonomic units (OTUs) with the highest abundance and prevalence could be annotated to Aphanizomenon NIES-81 and the second most profuse cyanobacterial taxon to Microcystis PCC 7914. In addition, two correlations were found, one between Aphanizomenon NIES-81 and saxitoxins and another between Microcystis PCC 7914 and microcystins. This study is of value to drinking water management and scientists involved in recognizing and controlling toxic cyanobacteria blooms.

High-Efficiency Photoinduced Charge Separation in Fe(III)carbene Thin Films.

Symmetry-breaking charge separation in molecular materials has attracted increasing attention for optoelectronics based on single-material active layers. To this end, Fe(III) complexes with particularly electron-donating N-heterocyclic carbene ligands offer interesting properties with a 2LMCT excited state capable of oxidizing or reducing the complex in its ground state. In this Communication, we show that the corresponding symmetry-breaking charge separation occurs in amorphous films of pristine [Fe(III)L2]PF6 (L = [phenyl(tris(3-methylimidazol-2-ylidene))borate]-). Excitation of the solid material with visible light leads to ultrafast electron transfer quenching of the 2LMCT excited state, generating Fe(II) and Fe(IV) products with high efficiency. Sub-picosecond charge separation followed by recombination in about 1 ns could be monitored by transient absorption spectroscopy. Photoconductivity measurements of films deposited on microelectrode arrays demonstrated that photogenerated charge carriers can be collected at external contacts.

Human intelectin-2 (ITLN2) is selectively expressed by secretory Paneth cells.

Intelectins (intestinal lectins) are highly conserved across chordate evolution and have been implicated in various human diseases, including Crohn's disease (CD). The human genome encodes two intelectin genes, intelectin-1 (ITLN1) and intelectin-2 (ITLN2). Other than its high sequence similarity with ITLN1, little is known about ITLN2. To address this void in knowledge, we report that ITLN2 exhibits discrete, yet notable differences from ITLN1 in primary structure, including a unique amino terminus, as well as changes in amino acid residues associated with the glycan-binding activity of ITLN1. We identified that ITLN2 is a highly abundant Paneth cell-specific product, which localizes to secretory granules, and is expressed as a multimeric protein in the small intestine. In surgical specimens of ileal CD, ITLN2 mRNA levels were reduced approximately five-fold compared to control specimens. The ileal expression of ITLN2 was unaffected by previously reported disease-associated variants in ITLN2 and CD-associated variants in neighboring ITLN1 as well as NOD2 and ATG16L1. ITLN2 mRNA expression was undetectable in control colon tissue; however, in both ulcerative colitis (UC) and colonic CD, metaplastic Paneth cells were found to express ITLN2. Together, the data reported establish the groundwork for understanding ITLN2 function(s) in the intestine, including its possible role in CD.

The IgGFc-binding protein FCGBP is secreted with all GDPH sequences cleaved but maintained by interfragment disulfide bonds.

Mucus forms an important protective barrier that minimizes bacterial contact with the colonic epithelium. Intestinal mucus is organized in a complex network with several specific proteins, including the mucin-2 (MUC2) and the abundant IgGFc-binding protein, FCGBP. FCGBP is expressed in all intestinal goblet cells and is secreted into the mucus. It is comprised of repeated von Willebrand D (vWD) domain assemblies, most of which have a GDPH amino acid sequence that can be autocatalytically cleaved, as previously observed in the mucins MUC2 and mucin-5AC. However, the functions of FCGBP in the mucus are not understood. We show that all vWD domains of FCGBP with a GDPH sequence are cleaved and that these cleavages occur early during biosynthesis in the endoplasmic reticulum. All cleaved fragments, however, remain connected via a disulfide bond within each vWD domain. This cleavage generates a C-terminal-reactive Asp-anhydride that could react with other molecules, such as MUC2, but this was not observed. Quantitative analyses by MS showed that FCGBP was mainly soluble in chaotropic solutions, whereas MUC2 was insoluble, and most of the secreted FCGBP was not covalently bound to MUC2. Although FCGBP has been suggested to bind immunoglobulin G, we were unable to reproduce this binding in vitro using purified proteins. In conclusion, while the function of FCGBP is still unknown, our results suggest that it does not contribute to covalent crosslinking in the mucus, nor incorporate immunoglobulin G into mucus, instead the single disulfide bond linking each fragment could mediate controlled dissociation.

A Fiber-Rich Diet and Radiation-Induced Injury in the Murine Intestinal Mucosa.

Dietary fiber is considered a strong intestinal protector, but we do not know whether dietary fiber protects against the long-lasting mucosal damage caused by ionizing radiation. To evaluate whether a fiber-rich diet can ameliorate the long-lasting pathophysiological hallmarks of the irradiated mucosa, C57BL/6J mice on a fiber-rich bioprocessed oat bran diet or a fiber-free diet received 32 Gray in four fractions to the distal colorectum using a linear accelerator and continued on the diets for one, six or 18 weeks. We quantified degenerating crypts, crypt fission, cell proliferation, crypt survival, macrophage density and bacterial infiltration. Crypt loss through crypt degeneration only occurred in the irradiated mice. Initially, it was most frequent in the fiber-deprived group but declined to levels similar to the fiber-consuming group by 18 weeks. The fiber-consuming group had a fast response to irradiation, with crypt fission for growth or healing peaking already at one week post-irradiation, while crypt fission in the fiber-deprived group peaked at six weeks. A fiber-rich diet allowed for a more intense crypt cell proliferation, but the recovery of crypts was eventually lost by 18 weeks. Bacterial infiltration was a late phenomenon, evident in the fiber-deprived animals and intensified manyfold after irradiation. Bacterial infiltration also coincided with a specific pro-inflammatory serum cytokine profile. In contrast, mice on a fiber-rich diet were completely protected from irradiation-induced bacterial infiltration and exhibited a similar serum cytokine profile as sham-irradiated mice on a fiber-rich diet. Our findings provide ample evidence that dietary fiber consumption modifies the onset, timing and intensity of radiation-induced pathophysiological processes in the intestinal mucosa. However, we need more knowledge, not least from clinical studies, before this finding can be introduced to a new and refined clinical practice.

Calcium-activated chloride channel regulator 1 (CLCA1) forms non-covalent oligomers in colonic mucus and has mucin 2-processing properties.

Calcium-activated chloride channel regulator 1 (CLCA1) is one of the major nonmucin proteins found in intestinal mucus. It is part of a larger family of CLCA proteins that share highly conserved features and domain architectures. The CLCA domain arrangement is similar to proteins belonging to the ADAM (a disintegrin and metalloproteinase) family, known to process extracellular matrix proteins. Therefore, CLCA1 is an interesting candidate in the search for proteases that process intestinal mucus. Here, we investigated CLCA1's biochemical properties both in vitro and in mucus from mouse and human colon biopsy samples. Using immunoblotting with CLCA1-specific antibodies and recombinant proteins, we observed that the CLCA1 C-terminal self-cleavage product forms a disulfide-linked dimer that noncovalently interacts with the N-terminal part of CLCA1, which further interacts to form oligomers. We also characterized a second, more catalytically active, N-terminal product of CLCA1, encompassing the catalytic domain together with its von Willebrand domain type A (VWA). This fragment was unstable but could be identified in freshly prepared mucus. Furthermore, we found that CLCA1 can cleave the N-terminal part of the mucus structural component MUC2. We propose that CLCA1 regulates the structural arrangement of the mucus and thereby takes part in the regulation of mucus processing.

Structural weakening of the colonic mucus barrier is an early event in ulcerative colitis pathogenesis.

OBJECTIVE: The colonic inner mucus layer protects us from pathogens and commensal-induced inflammation, and has been shown to be defective in active UC. The aim of this study was to determine the underlying compositional alterations, their molecular background and potential contribution to UC pathogenesis. DESIGN: In this single-centre case-control study, sigmoid colon biopsies were obtained from patients with UC with ongoing inflammation (n=36) or in remission (n=28), and from 47 patients without colonic disease. Mucus samples were collected from biopsies ex vivo, and their protein composition analysed by nanoliquid chromatography-tandem mass spectrometry. Mucus penetrability and goblet cell responses to microbial stimulus were assessed in a subset of patients. RESULTS: The core mucus proteome was found to consist of a small set of 29 secreted/transmembrane proteins. In active UC, major structural mucus components including the mucin MUC2 (p<0.0001) were reduced, also in non-inflamed segments. Active UC was associated with decreased numbers of sentinel goblet cells and attenuation of the goblet cell secretory response to microbial challenge. Abnormal penetrability of the inner mucus layer was observed in a subset of patients with UC (12/40; 30%). Proteomic alterations in penetrable mucus samples included a reduction of the SLC26A3 apical membrane anion exchanger, which supplies bicarbonate required for colonic mucin barrier formation. CONCLUSION: Core mucus structural components were reduced in active UC. These alterations were associated with attenuation of the goblet cell secretory response to microbial challenge, but occurred independent of local inflammation. Thus, mucus abnormalities are likely to contribute to UC pathogenesis.

Release of astroglial vimentin by extracellular vesicles: Modulation of binding and internalization of C3 transferase in astrocytes and neurons.

Clostridium botulinum C3 transferase (C3bot) ADP-ribosylates rho proteins to change cellular functions in a variety of cell types including astrocytes and neurons. The intermediate filament protein vimentin as well as transmembrane integrins are involved in internalization of C3bot into cells. The exact contribution, however, of these proteins to binding of C3bot to the cell surface and subsequent cellular uptake remains to be unraveled. By comparing primary astrocyte cultures derived from wild-type with Vim-/- mice, we demonstrate that astrocytes lacking vimentin exhibited a delayed ADP-ribosylation of rhoA concurrent with a blunted morphological response. This functional impairment was rescued by the extracellular excess of recombinant vimentin. Binding assays using C3bot harboring a mutated integrin-binding RGD motif (C3bot-G89I) revealed the involvement of integrins in astrocyte binding of C3bot. Axonotrophic effects of C3bot are vimentin dependent and postulate an underlying mechanism entertaining a molecular cross-talk between astrocytes and neurons. We present functional evidence for astrocytic release of vimentin by exosomes using an in vitro scratch wound model. Exosomal vimentin+ particles released from wild-type astrocytes promote the interaction of C3bot with neuronal membranes. This effect vanished when culturing Vim-/- astrocytes. Specificity of these findings was confirmed by recombinant vimentin propagating enhanced binding of C3bot to synaptosomes from rat spinal cord and mouse brain. We hypothesize that vimentin+ exosomes released by reactive astrocytes provide a novel molecular mechanism constituting axonotrophic (neuroprotective) and plasticity augmenting effects of C3bot after spinal cord injury.

Cesium Bismuth Iodide Solar Cells from Systematic Molar Ratio Variation of CsI and BiI3.

Metal halide compounds with photovoltaic properties prepared from solution have received increased attention for utilization in solar cells. In this work, low-toxicity cesium bismuth iodides are synthesized from solution, and their photovoltaic and optical properties as well as electronic and crystal structures are investigated. The X-ray diffraction patterns reveal that a CsI/BiI3 precursor ratio of 1.5:1 can convert pure rhombohedral BiI3 to pure hexagonal Cs3Bi2I9, but any ratio intermediate of this stoichiometry and pure BiI3 yields a mixture containing the two crystalline phases Cs3Bi2I9 and BiI3, with their relative fraction depending on the CsI/BiI3 ratio. Solar cells from the series of compounds are characterized, showing the highest efficiency for the compounds with a mixture of the two structures. The energies of the valence band edge were estimated using hard and soft X-ray photoelectron spectroscopy for more bulk and surface electronic properties, respectively. On the basis of these measurements, together with UV-vis-near-IR spectrophotometry, measuring the band gap, and Kelvin probe measurements for estimating the work function, an approximate energy diagram has been compiled clarifying the relationship between the positions of the valence and conduction band edges and the Fermi level.

Difference in Outcome Following Surgery for Native Aortic and Mitral Valve Infective Endocarditis.

BACKGROUND: We investigated differences in clinical presentation, microbiology, and short- and long-term results according to the affected valve in patients who underwent surgery for left-sided native valve infective endocarditis (IE). METHODS: This was a single-center retrospective study of 117 patients with isolated mitral valve IE (group M) and 140 patients with isolated aortic valve IE (group A) who underwent surgery between 1998 and 2015. RESULTS: The mean age of patients in group M was 62 ± 14 years, whereas in group A the patients were 56 ± 14 years old (p = 0.001). There were 61 females (52% of patients) in group M and 31 females (22% of patients) in group A (p < 0.001). Abscesses were more common in group A than in group B. Staphylococcus aureus was more frequent in group M (47%, n = 55) than in group A (21%, n = 30; p < 0.001). The length of time from symptom onset to surgery was longer in group A than in group M, but the time from diagnosis to surgery was shorter in group A than in group M. Ninety-day mortality was similar in group M and group A in patients operated within 48 hours after diagnosis, but in patients who were operated more than 48 hours after diagnosis the 90-day mortality was 15% in group M and 3% in group A (p = 0.006). CONCLUSION: There were considerable differences in preoperative characteristics, microbiology, timing of surgery, and outcomes between patients who underwent surgery for isolated aortic valve IE and those who were operated for isolated mitral valve IE.

Gram-positive bacteria are held at a distance in the colon mucus by the lectin-like protein ZG16.

The distal colon functions as a bioreactor and harbors an enormous amount of bacteria in a mutualistic relationship with the host. The microbiota have to be kept at a safe distance to prevent inflammation, something that is achieved by a dense inner mucus layer that lines the epithelial cells. The large polymeric nets made up by the heavily O-glycosylated MUC2 mucin forms this physical barrier. Proteomic analyses of mucus have identified the lectin-like protein ZG16 (zymogen granulae protein 16) as an abundant mucus component. To elucidate the function of ZG16, we generated recombinant ZG16 and studied Zg16-/- mice. ZG16 bound to and aggregated Gram-positive bacteria via binding to the bacterial cell wall peptidoglycan. Zg16-/- mice have a distal colon mucus layer with normal thickness, but with bacteria closer to the epithelium. Using distal colon explants mounted in a horizontal perfusion chamber we demonstrated that treatment of bacteria with recombinant ZG16 hindered bacterial penetration into the mucus. The inner colon mucus of Zg16-/- animals had a higher load of Gram-positive bacteria and showed bacteria with higher motility in the mucus close to the host epithelium compared with cohoused littermate Zg16+/+ The more penetrable Zg16-/- mucus allowed Gram-positive bacteria to translocate to systemic tissues. Viable bacteria were found in spleen and were associated with increased abdominal fat pad mass in Zg16-/- animals. The function of ZG16 reveals a mechanism for keeping bacteria further away from the host colon epithelium.

Genome sequencing and conservation genomics in the Scandinavian wolverine population.

Genetic approaches have proved valuable to the study and conservation of endangered populations, especially for monitoring programs, and there is potential for further developments in this direction by extending analyses to the genomic level. We assembled the genome of the wolverine (Gulo gulo), a mustelid that in Scandinavia has recently recovered from a significant population decline, and obtained a 2.42 Gb draft sequence representing >85% of the genome and including >21,000 protein-coding genes. We then performed whole-genome resequencing of 10 Scandinavian wolverines for population genomic and demographic analyses. Genetic diversity was among the lowest detected in a red-listed population (mean genome-wide nucleotide diversity of 0.05%). Results of the demographic analyses indicated a long-term decline of the effective population size (Ne ) from 10,000 well before the last glaciation to <500 after this period. Current Ne appeared even lower. The genome-wide FIS level was 0.089 (possibly signaling inbreeding), but this effect was not observed when analyzing a set of highly variable SNP markers, illustrating that such markers can give a biased picture of the overall character of genetic diversity. We found significant population structure, which has implications for population connectivity and conservation. We used an integrated microfluidic circuit chip technology to develop an SNP-array consisting of 96 highly informative markers that, together with a multiplex pre-amplification step, was successfully applied to low-quality DNA from scat samples. Our findings will inform management, conservation, and genetic monitoring of wolverines and serve as a genomic roadmap that can be applied to other endangered species. The approach used here can be generally utilized in other systems, but we acknowledge the trade-off between investing in genomic resources and direct conservation actions.

Correction: Ultrafast dye regeneration in a core-shell NiO-dye-TiO2 mesoporous film.

Correction for 'Ultrafast dye regeneration in a core-shell NiO-dye-TiO2 mesoporous film' by Lei Tian et al., Phys. Chem. Chem. Phys., 2018, 20, 36-40.

A glassy carbon electrode modified with TiO2(200)-rGO hybrid nanosheets for aptamer based impedimetric determination of the prostate specific antigen.

TiO2(200)-rGO hybrid nanosheets were synthesized starting from TiO2, rGO and NaOH solid powders via a scalable hydrothermal process. The weight ratio of TiO2-GO was found to be crucial on the crystal growth and biosensor properties of the final hybrid nanosheets. They were characterized by means of SEM, FESEM-EDX, XRD, XPS, Raman and FTIR spectroscopies in order to verify the formation of very thin TiO2 anatase nanosheets with an orientation of the anatase crystal structure towards the (200) plane. The free active sites of TiO2 structure and the large surface of the 2D graphene structure strongly facilitate charge transport confirmed by BET-BJH analyses. Compared to pure AuNPs, rGO and TiO2, the hybrid nanosheet modified electrode represents the most sensitive aptasensing platform for the determination of PSA. The detection was based on that the variation of electron transfer resistance (Rct) at the modified electrode surface in a solution containing 3.0 mmol L-1 [Fe(CN)6]3-/4- as a redox probe and 0.1 mol L-1 KCl as supporting electrolyte. The detection limit of the sensor is 1 pg mL-1, and the sensor can be operated up to 30 days. It was applied to the analysis of PSA levels in spiked serum samples obtained from patients with prostate cancer. Data compare well with those obtained by an immunoradiometric assay. Graphical abstract Scalable reduced graphene oxide (rGO)-TiO2(200) mesoporous hybrid nanosheets with large surface area and new crystal growth of anatase (A) are introduced as efficient, durable, selective with low detection limit aptamer based prostate specific antigen biosensor.

The mucus and mucins of the goblet cells and enterocytes provide the first defense line of the gastrointestinal tract and interact with the immune system.

The gastrointestinal tract is covered by mucus that has different properties in the stomach, small intestine, and colon. The large highly glycosylated gel-forming mucins MUC2 and MUC5AC are the major components of the mucus in the intestine and stomach, respectively. In the small intestine, mucus limits the number of bacteria that can reach the epithelium and the Peyer's patches. In the large intestine, the inner mucus layer separates the commensal bacteria from the host epithelium. The outer colonic mucus layer is the natural habitat for the commensal bacteria. The intestinal goblet cells secrete not only the MUC2 mucin but also a number of typical mucus components: CLCA1, FCGBP, AGR2, ZG16, and TFF3. The goblet cells have recently been shown to have a novel gate-keeping role for the presentation of oral antigens to the immune system. Goblet cells deliver small intestinal luminal material to the lamina propria dendritic cells of the tolerogenic CD103(+) type. In addition to the gel-forming mucins, the transmembrane mucins MUC3, MUC12, and MUC17 form the enterocyte glycocalyx that can reach about a micrometer out from the brush border. The MUC17 mucin can shuttle from a surface to an intracellular vesicle localization, suggesting that enterocytes might control and report epithelial microbial challenge. There is communication not only from the epithelial cells to the immune system but also in the opposite direction. One example of this is IL10 that can affect and improve the properties of the inner colonic mucus layer. The mucus and epithelial cells of the gastrointestinal tract are the primary gate keepers and controllers of bacterial interactions with the host immune system, but our understanding of this relationship is still in its infancy.

Searching the Evolutionary Origin of Epithelial Mucus Protein Components-Mucins and FCGBP.

The gel-forming mucins are large glycosylated proteins that are essential components of the mucus layers covering epithelial cells. Using novel methods of identifying mucins based on profile hidden Markov models, we have found a large number of such proteins in Metazoa, aiding in their classification and allowing evolutionary studies. Most vertebrates have 5-6 gel-forming mucin genes and the genomic arrangement of these genes is well conserved throughout vertebrates. An exception is the frog Xenopus tropicalis with an expanded repertoire of at least 26 mucins of this type. Furthermore, we found that the ovomucin protein, originally identified in chicken, is characteristic of reptiles, birds, and amphibians. Muc6 is absent in teleost fish, but we now show that it is present in animals such as ghost sharks, demonstrating an early origin in vertebrate evolution. Public RNA-Seq data were analyzed with respect to mucins in zebrafish, frog, and chicken, thus allowing comparison in regard of tissue and developmental specificity. Analyses of invertebrate proteins reveal that gel-forming-mucin type of proteins is widely distributed also in this group. Their presence in Cnidaria, Porifera, and in Ctenophora (comb jellies) shows that these proteins were present early in metazoan evolution. Finally, we examined the evolution of the FCGBP protein, abundant in mucus and related to gel-forming mucins in terms of structure and localization. We demonstrate that FCGBP, ubiquitous in vertebrates, has a conserved N-terminal domain. Interestingly, this domain is also present as an N-terminal sequence in a number of bacterial proteins.