Extracellular Mucus Research Articles

Primary adenocarcinoma of the spermatic cord: a case report and review of the literature

BackgroundPrimary malignant neoplasms of the spermatic cord are extremely rare, with most reported cases being sarcomas or metastatic carcinomas. However, primary adenocarcinoma of the spermatic cord has not been previously reported.Case presentationA 34-year-old male with a solid mass in the right spermatic cord, was eventually diagnosed with primary adenocarcinoma. Histological examination revealed a moderately-to-poorly differentiated adenocarcinoma exhibiting glandular, cribriform, or nested growth patterns, characterized by medium to large-sized cells and focal extracellular mucus. Immunohistochemical analysis demonstrated positive staining for CK (AE1/AE3), CK8/18, CK19, MOC31 (EP-CAM), and Ber-EP4, while negative staining was observed for CK7, D2-40, WT-1, MC, PAX-8, NKX3.1, PSA, CEA, TTF-1, and NapsinA. Furthermore, a complete loss of INI-1 expression and consistent BRG1 expression were noted in all tumor cells. Next-generation sequencing revealed SMARCB1 deletion, low tumor mutation burden (TMB-L), and microsatellite stability (MSS).ConclusionWe reported the first case of primary adenocarcinoma of the spermatic cord with SMARCB1 (INI-1) deficiency. This case contributes to the expanding understanding of rare neoplasms and underscores the importance of further research into therapeutic strategies targeting SMARCB1-deficient tumors.

Genome sequence of Alteromonas macleodii strain OCN004 isolated from the extracellular mucus of an apparently healthy rice coral (Montipora capitata).

Alteromonas macleodii strain OCN004, a marine gammaproteobacterium in the Alteromonadaceae family, has primarily been studied as a non-pathogenic negative control bacterium during laboratory infection trials to test the virulence of bacterial coral pathogens. The draft genome sequence of A. macleodii strain OCN004 is presented here.

Pan-Genome Analyses of the Genus Cohnella and Proposal of the Novel Species Cohnella silvisoli sp. nov., Isolated from Forest Soil.

Two strains, designated NL03-T5T and NL03-T5-1, were isolated from a soil sample collected from the Nanling National Forests, Guangdong Province, PR China. The two strains were Gram-stain-positive, aerobic, rod-shaped and had lophotrichous flagellation. Strain NL03-T5T could secrete extracellular mucus whereas NL03-T5-1 could not. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the two strains belong to the genus Cohnella, were most closely related to Cohnella lupini LMG 27416T (95.9% and 96.1% similarities), and both showed 94.0% similarity with Cohnella arctica NRRL B-59459T, respectively. The two strains showed 99.8% 16S rRNA gene sequence similarity between them. The draft genome size of strain NL03-T5T was 7.44 Mbp with a DNA G+C content of 49.2 mol%. The average nucleotide identities (ANI) and the digital DNA-DNA hybridization (dDDH) values between NL03-T5T and NL03-T5-1 were 99.98% and 100%, indicating the two strains were of the same species. Additionally, the ANI and dDDH values between NL03-T5T and C. lupini LMG 27416T were 76.1% and 20.4%, respectively. The major cellular fatty acids of strain NL03-T5T included anteiso-C15:0 and iso-C16:0. The major polar lipids and predominant respiratory quinone were diphosphatidylglycerol (DPG) and menaquinone-7 (MK-7). Based on phylogenetic analysis, phenotypic and chemotaxonomic characterization, genomic DNA G+C content, and ANI and dDDH values, strains NL03-T5T and NL03-T5-1 represent novel species in the genus Cohnella, for which the name Cohnella silvisoli is proposed. The type strain is NL03-T5T (=GDMCC 1.2294T = JCM 34999T). Furthermore, comparative genomics revealed that the genus Cohnella had an open pan-genome. The pan-genome of 29 Cohnella strains contained 41,356 gene families, and the number of strain-specific genes ranged from 6 to 1649. The results may explain the good adaptability of the Cohnella strains to different habitats at the genetic level.

Histochemistry and transcriptomics of mucins and peritrophic membrane (PM) proteins along the midgut of a beetle with incomplete PM and their complementary function

The midgut of Zabrotes subfasciatus (Coleoptera) and other insects may have regions lacking a peritrophic membrane (matrix, PM) and covered with a jelly-like material known as peritrophic gel. This work was undertaken to test the hypothesis that the peritrophic gel is a vertebrate-like mucus. By histochemistry we identified mucins along the whole midgut, which contrasts with the known occurrence of PM only at the posterior midgut. We also analyzed the expression of the genes coding for mucus-forming mucins (Mf-mucins), peritrophins, chitin synthases and chitin deacetylases along the midgut and carcass (insect without midgut) by RNA-seq. Mf-mucins were identified as proteins with high O-glycosylation and multiple tandem repeats of Pro/Thr/Ser residues. Peritrophins were separated into PM proteins, cuticular proteins analogous to peritrophins (CPAPs) and ubiquitous-chitin-binding domain-(CBD)-containing proteins (UCBPs). PM proteins have at least 3, CPAP one or 3, and UCBPs have a varied number of CBDs. PM proteins are more expressed at midgut, CPAP at the carcass, and UCBP at both. The results showed that most PM proteins are mainly expressed at the posterior midgut, together with midgut chitin synthase and chitin deacetylase, and in agreement with the presence of PM only at the posterior midgut by visual inspection. The excretion of most midgut chitinase is avoided, suggesting that the shortened PM is functional. Mf-mucins are expressed along the whole midgut, probably forming the extracellular mucus layer observed by histochemistry. Thus, the lack of PM at anterior and middle midgut causes the exposure of a mucus, which may correspond to the previously described peritrophic gel. The putative functional interplay of mucus and PM is discussed. The major role of mucus is proposed to be tissue protection and of PM to enhancing digestive efficiency by allowing enzyme recycling.

Interleukin 13-Induced Inflammation Increases DPP4 Abundance but Does Not Enhance Middle East Respiratory Syndrome Coronavirus Replication in Airway Epithelia.

Chronic pulmonary conditions such as asthma and chronic obstructive pulmonary disease increase the risk of morbidity and mortality during infection with the Middle East respiratory syndrome coronavirus (MERS-CoV). We hypothesized that individuals with such comorbidities are more susceptible to MERS-CoV infection due to increased expression of its receptor, dipeptidyl peptidase 4 (DPP4). We modeled chronic airway disease by treating primary human airway epithelia with the Th2 cytokine interleukin 13 (IL-13), examining how this affected DPP4 protein levels with MERS-CoV entry and replication. IL-13 exposure for 3 days led to greater DPP4 protein abundance, while a 21-day treatment raised DPP4 levels and caused goblet cell metaplasia. Surprisingly, despite this increase in receptor availability, MERS-CoV entry and replication were not significantly affected by IL-13 treatment. Our results suggest that greater DPP4 abundance is likely not the primary mechanism leading to increased MERS severity in the setting of Th2 inflammation. Transcriptional profiling analysis highlighted the complexity of IL-13-induced changes in airway epithelia, including altered expression of genes involved in innate immunity, antiviral responses, and maintenance of the extracellular mucus barrier. These data suggest that additional factors likely interact with DPP4 abundance to determine MERS-CoV infection outcomes.

Diversity of CysD domains in gel-forming mucins.

CysD domains are disulfide-rich modules embedded within long O-glycosylated regions of mucin glycoproteins. CysD domains are thought to mediate intermolecular adhesion during the intracellular bioassembly of mucin polymers and perhaps also after secretion in extracellular mucus hydrogels. The human genome encodes 18 CysD domains distributed across three different mucins. To date, experimental structural information is available only for the first CysD domain (CysD1) of the intestinal mucin MUC2, which is one of the most divergent of the CysDs. To provide experimental data on a CysD that is representative of a larger branch of the fold family, we determined the crystal structure of the seventh CysD domain (CysD7) from MUC5AC, a mucin found in the respiratory tract and stomach. The MUC5AC CysD7 structure revealed a single calcium-binding site, contrasting with the two sites in MUC2 CysD1. The MUC5AC CysD7 structure also contained an additional α-helix absent from MUC2 CysD1, with potential functional implications for intermolecular interactions. Lastly, the experimental structure emphasized the flexibility of the loop analogous to the main adhesion loop of MUC2 CysD1, suggesting that both sequence divergence and physical plasticity in this region may contribute to the adaptation of mucin CysD domains.

The clinicopathological and immunohistochemical features of breast carcinomas with signet-ring-cell differentiation

BackgroundThis study investigated the clinicopathological features, immunophenotypic characteristics and differential diagnosis of primary breast carcinomas with signet ring cell differentiation, as well as differences in the traits of signet ring-like cell mucin.MethodsA total of five cases of primary breast cancer diagnosed with signet ring cell differentiation and treated at The First People’s Hospital of Jingmen from January 2016 to December 2021 were collected. HE, immunohistochemical staining, and AB-PAS staining were used for the analysis.ResultsAlthough we strictly selected all the primary breast cancer cases with signet ring cell differentiation, there were differences in the arrangement of the cells and the grading of nuclei. Our immunohistochemical results showed that the ER was consistently strongly positive, and the PR expression was not consistent, while all the cases of HER2 were negative. CK7 was negative in one case, and CK20 and CK5/6 were not expressed in all the cases. The mucin MUC1 was positive and showed two patterns. MUC2 was strongly positive in all the cases. All the cases were negative for CDX2, SATB2, PAX8, TTF-1, and Napsin A, while the positive expression of COX2, Villin, and WT-1 was not constant. One case expressed neuroendocrine markers. The expression level of Ki67 was between 10 and 30%. AB (pH 2.5)-PAS staining revealed that the intracellular mucus contained more cells with neutral mucus, while the extracellular mucus was mainly acidic.ConclusionWe found that histological morphology, cell morphology, and nuclear grading differentiate among different cases. The immunohistochemical characteristics of primary breast cancers diagnosed with signet ring cell differentiation are helpful for identification. The differences in the expression patterns of mucins may be related to unfavorable clinicopathological factors, but their usefulness as a prognostic marker remains to be further understood. The heterogeneity of cell mucus, the differentiation of tumor cells, and the phenotypic changes of tumors also need further study.

Goblet cell adenocarcinoma in the digestive system: a clinicopathological analysis of 22 cases

Objective: To investigate the clinical features, morphological characteristics, immunophenotype, and differential diagnosis of goblet cell adenocarcinoma (GCA) in the digestive system. Methods: The clinicopathological data, morphological characteristics, immunophenotypes of 22 cases of GCA in the digestive system diagnosed from January 2010 to January 2021 were collected. Meanwhile, 25 cases of neuroendocrine neoplasm (NEN) and 24 cases of adenocarcinoma were used as controls. Relevant literature was also reviewed. Results: There were 16 males and 6 females, aged from 36 to 79 years with an average of 56 years. The anatomical sites of the 22 GCA were mostly appendix (17 cases) and occasionally extra-appendix (5 cases), including 3 cases in stomach, 1 case in duodenum and 1 case in anal. All 17 cases of appendiceal GCA were pure GCA. Among the 5 cases of extra-appendiceal GCA, One case of gastric GCA was pure, two cases of gastric GCA with NEN or adenocarcinoma, duodenal GCA with NEN and adenocarcinoma, anal GCA with NEN.Low-grade GCAs were composed of goblet, Paneth and neuroendocrine cells, which were arranged in intestinal crypt tubular or cluster structures and distributed in the wall of digestive system. The tubular and cluster structures lacked adhesion. Goblet cells were columnar, located in the base, with clear cytoplasm, small nuclei, inconspicuous atypia, and uncommon mitoses. Extracellular mucus and signet-ring cells with nuclear variations could be seen in some cases. Nerve fiber bundle invasion and tumor thrombus in vessels were often present. High-grade GCAs lacked tubular and cluster structures, and their histological structures were more complex. Tumor cells expressed mixed neuroendocrine and glandular epithelial markers. Similar to the expression patterns of synaptophysin and chromogranin A, CD200 and INSM1 were also dot-like or patch-positive in GCA. Conclusions: GCA is an infrequent tumor of the digestive system and shows the bi-directional differentiation characteristics of neuroendocrine and glandular epithelium. Accurate diagnosis and staging are related to its prognosis.

453. THE EFFECTIVITY OF NEOADJUVANT CHEMORADIOTHERAPY IN ESOPHAGEAL ADENOCARCINOMA WITH PRESENCE OF EXTRACELLULAR MUCINE, SIGNET-RING CELLS OR POORLY COHESIVE CELLS

Abstract Five-year overall survival of patients with locally advanced esophageal adenocarcinoma treated with neoadjuvant chemoradiotherapy (nCRT) followed by surgery is 40%. Better understanding of histopathological factors that influence treatment response is necessary to identify patients with expected poor prognosis. Aim of the study was to assess whether pre- and post-treatment presence of excessive (≥1%) extracellular mucus accumulation, signet-ring cells (SRC) and/or poorly cohesive cells were associated with poor response to nCRT, independent of tumor differentiation grade. This was a retrospective cohort study. Patients included were diagnosed with an adenocarcinoma of the esophagus or GEJ, who underwent CROSS and were planned to undergo esophagectomy between 2001–2019 at two university hospitals. Percentages of the factors extracellular mucus, SRC and poorly cohesive cells were scored by experienced pathologists in pre-treatment biopsies and resection specimen slides relative to the primary tumor area. Multivariable logistic regression models and Cox proportional-hazards models were used to evaluate the histopathological factors in relation to tumor regression grade (TRG) 1–2 (<10% tumor) vs TRG 3–4 (>10% tumor), overall survival (OS) and disease-free survival (DFS). Some 325 patients were included (median age 65 years, 280/325 (86%) male). In pre-treatment biopsies, ≥1% extracellular mucus was present in 66/325 (20%); ≥1% SRC 43/325 (13%); ≥1% poorly cohesive cells 126/325 (39%). In patients undergoing esophagectomy, 150/284 (53%) had TRG 3–4. Median OS in all patients was 44 months (95%CI: 36–62). Factors in pre-treatment biopsies were not associated with outcomes independent of differentiation grade. Only patients with ≥1% SRC in the resection specimen had poorer OS (Fig 1): HR for death 1.71, 95%CI: 1.06–2.76, adjusted for age, sex, pre-treatment pathological tumor and nodal stage (pre-pT/pre-pN), ypN and tumor differentiation grade. Extracellular mucus accumulation, SRC and/or poorly cohesive cells in pre-treatment biopsies in patients with esophageal adenocarcinoma treated with nCRT are not associated with response to nCRT, OS or DFS. Their presence should not be a reason to refrain from CROSS nCRT. However, persistence of SRC in the resection specimen after nCRT is an indicator of poor prognosis.

Inosine and D-Mannose Secreted by Drug-Resistant Klebsiella pneumoniae Affect Viability of Lung Epithelial Cells.

The antibiotic resistance rates of Klebsiella pneumoniae have been steadily increasing in recent years. Nevertheless, the metabolic features of the drug-resistant Klebsiella pneumoniae and its associated benefits for bacterial pathogenicity are far from expounded. This study aims to unravel the unique physiological and metabolic properties specific to drug-resistant K. pneumoniae. Using scanning electron microscopy (SEM), we observed a thicker extracellular mucus layer around a drug-resistant K. pneumonia strain (Kp-R) than a drug-sensitive K. pneumonia strain (Kp-S). Kp-R also produced more capsular polysaccharide (CPS) and biofilm, and appeared to have a significant competitive advantage when co-cultured with Kp-S. Moreover, Kp-R was easier to adhere to and invade A549 epithelial cells than Kp-S but caused less cell-viability damage according to cell counting kit-8 (CCK-8) tests. Immunofluorescence revealed that both Kp-R and Kp-S infection destroyed the tight junctions and F-actin of epithelial cells, while the damage caused by Kp-S was more severe than Kp-R. We detected the extracellular metabolites secreted by the two strains with UHPLC-Q-TOF MS to explore the critical secretion products. We identified 16 predominant compounds that were differentially expressed. Among them, inosine increased the viability of epithelial cells in a dose-dependent manner, and an A2AR antagonist can abolish such enhancement. D-mannose, which was secreted less in Kp-R, inhibited the viability of A549 cells in the range of low doses. These findings provide potential targets and research strategies for preventing and treating drug-resistant K. pneumoniae infections.

A Model of Potassium‐Assisted Olfactory Sensory Neuron Response to Odorant

Odorants interact with specialized G‐protein coupled receptors lining the cilia of the olfactory sensory neuron initiating an intracellular cascade of signal transduction events resulting in cAMP‐gated ion channel opening and generation of ion currents. These ion currents polarize the cilia membrane resulting in the voltage transition across the olfactory epithelium, which can be recorded as an electroolfactogram (EOG). The observed dose‐dependent change of the EOG amplitude after stimulation of olfactory epithelium with the mixture of odorant and electron donors and acceptors indicates a potential involvement of electrons in the initial events of signal transduction. Our model of signal transduction consists of a dimer of the G‐protein coupled olfactory receptors positioned vertically in the phospholipid bilayer between olfactory extracellular mucus layer and the intracellular cytoplasm, within the cilia of the olfactory sensory neuron. In this model, two identical receptors of the dimer form an odorant activated potassium ion channel. Prior to odorant binding at the receptor, the ion channel gate is closed. Each receptor has a single biding site for the odorant molecule on the extracellular end located within the mucus layer, and a binding site for the heterotrimeric G‐protein complex within the cytoplasm. The brief binding of odorant molecules to the mucosal part of the receptors causes the ion channel to open and pass intracellular potassium ions to the extracellular mucus layer. The potassium‐coupled electrons polarize the cytoplasmic portion of the receptors and facilitate activation of the bound G‐protein complex thereby influencing the subsequent signal cascade.

Shaping nanoparticle diffusion through biological barriers to drug delivery

Nanoparticle drug delivery systems encounter many biological barriers, such as the extracellular matrix and mucus gels, that they must bypass to gain access to target cells. A design parameter that has recently gained attention is nanoparticle shape, as it has been shown elongated rod–shaped nanoparticles achieve higher diffusion rates through biological gels. However, the optimal dimensions of rod-shaped nanoparticles to enhance this effect has yet to be established. To systematically approach this, rod-shaped nanoparticles were synthesized by mechanically stretching 100 ​nm, 200 ​nm, and 500 ​nm spherical nanoparticles. Transmission electron microscopy confirmed this procedure yields a significant fraction of elongated rods and remaining spheres could be removed by centrifugation. Fluorescent microscopy and multiple particle tracking analysis was then used to characterize rod-shaped and spherical nanoparticle diffusion in MaxGel®, a model extracellular matrix hydrogel. When dispersed in MaxGel, we found rod-shaped nanoparticles exhibited the greatest enhancement in diffusion rate when their length far exceeds the average hydrogel network size. These results further establish the importance of shape as a design criterion to improve nanoparticle-based drug delivery systems.

Mucus, Microbiomes and Pulmonary Disease.

The respiratory tract harbors a stable and diverse microbial population within an extracellular mucus layer. Mucus provides a formidable defense against infection and maintaining healthy mucus is essential to normal pulmonary physiology, promoting immune tolerance and facilitating a healthy, commensal lung microbiome that can be altered in association with chronic respiratory disease. How one maintains a specialized (healthy) microbiome that resists significant fluctuation remains unknown, although smoking, diet, antimicrobial therapy, and infection have all been observed to influence microbial lung homeostasis. In this review, we outline the specific role of polymerizing mucin, a key functional component of the mucus layer that changes during pulmonary disease. We discuss strategies by which mucin feed and spatial orientation directly influence microbial behavior and highlight how a compromised mucus layer gives rise to inflammation and microbial dysbiosis. This emerging field of respiratory research provides fresh opportunities to examine mucus, and its function as predictors of infection risk or disease progression and severity across a range of chronic pulmonary disease states and consider new perspectives in the development of mucolytic treatments.

Tuning Selective Transport of Biomolecules through Site-Mutated Nucleoporin-like Protein (NLP) Hydrogels.

Natural selective filtering systems (e.g., the extracellular matrix, nuclear pores, and mucus) separate molecules selectively and efficiently, and the detailed understanding of transport mechanisms exploited in these systems provides important bioinspired design principles for selective filters. In particular, nucleoporins consist of consensus repeat sequences that are readily utilized for engineering repeat proteins. Here, the consensus repeat sequence of Nsp1, a yeast nucleoporin, is polymerized to form a nucleoporin-like protein (NLP) and mutated to understand the effect of sequence on selective transport. The hydrophilic spacers of the NLPs were redesigned considering net charge, charge distribution, and polarity. Mutations were made near to and far from the FSFG interacting domain to explore the role of highly conserved residues as a function of spatial proximity. A nuclear transport receptor-cargo complex, nuclear transport factor 2-green fluorescent protein (NTF2-GFP), was used as a model for changes in transport. For mutations of the charged spacer, some mutations of highly conserved charged residues were possible without knocking out selective transport of the NTF2, but the formation of regions of clustered negative charge has an unfavorable effect on nuclear transporter permeation. Thus, positive net charge and alternating positive and negative charge within the hydrophilic spacer are advantageous for recognition and selective transport. In the polarity panel, mutations that increased the interaction between NTF2-GFP and the gel led to decreased permeation of the NTF2-GFP due to blocking of the interface and inability of the NTF2-GFP to transport into the gel. Therefore, these results provide a strategy for tuning selective permeability of biomolecules using the artificially designed consensus repeat-based hydrogels.

Obstructive lung diseases and allergic bronchopulmonary aspergillosis.

Allergic bronchopulmonary aspergillosis (ABPA) is a disease frequently complicating asthma and cystic fibrosis. ABPA is increasingly recognized in other obstructive lung diseases (OLDs), including chronic obstructive pulmonary disease (COPD) and noncystic fibrosis bronchiectasis. Herein, we summarize the recent developments in ABPA complicating OLDs. Recent research has described the clinical features and natural history of ABPA complicating asthma in children and the elderly. We have gained insights into the pathophysiology of ABPA, especially the role of eosinophil extracellular trap cell death and mucus plugs. The utility of recombinant fungal antigens in the diagnosis of ABPA has been established. Newer, more sensitive criteria for the diagnosis of ABPA have been proposed. Although ABPA is uncommon in COPD and noncystic fibrosis bronchiectasis, aspergillus sensitization is more common and is associated with a higher exacerbation rate. Several advances have occurred in the diagnosis and treatment of ABPA in recent years. However, there is an unmet need for research into the genetic predisposition, pathophysiology, and treatment of ABPA. Apart from asthma and cystic fibrosis, patients with other OLDs also require evaluation for Aspergillus sensitization and ABPA.

Neutrophil Extracellular Traps Increase Airway Mucus Viscoelasticity and Slow Mucus Particle Transit.

Mucus obstruction is a key feature of many inflammatory airway diseases. Neutrophil extracellular traps (NETs) are released upon neutrophil stimulation and consist of extracellular chromatin networks studded with cytotoxic proteins. When released in the airways, these NETs can become part of the airway mucus. We hypothesized that the extracellular DNA and/or oxidative stress (e.g., by the release of reactive oxygen species and myeloperoxidase during NETs formation in the airways) would increase mucus viscoelasticity. We collected human airway mucus from endotracheal tubes of healthy patients admitted for elective surgery and coincubated these samples with NETs from phorbol 12-myristate 13-acetate-stimulated neutrophils. Unstimulated neutrophils served as controls, and blocking experiments were performed with dornase alfa for extracellular DNA and the free radical scavenger dimethylthiourea for oxidation. Compared with controls, the coincubation of mucus with NETs resulted in 1) significantly increased mucus viscoelasticity (macrorheology) and 2) significantly decreased mesh pore size of the mucus and decreased movement of muco-inert nanoparticles through the mucus (microrheology), but 3) NETs did not cause visible changes in the microstructure of the mucus by scanning EM. Incubation with either dornase alfa or dimethylthiourea attenuated the observed changes in macrorheology and microrheology. This suggests that the release of NETs may contribute to airway mucus obstruction by increasing mucus viscoelasticity and that this effect is not solely due to the release of DNA but may in part be due to oxidative stress.

Improved chemosensitivity following mucolytic therapy in patient-derived models of mucinous appendix cancer

Abundant intraperitoneal (IP) accumulation of extracellular mucus in patients with appendiceal mucinous carcinoma peritonei (MCP) causes compressive organ dysfunction and prevents delivery of chemotherapeutic drugs to cancer cells. We hypothesized that reducing extracellular mucus would decrease tumor-related symptoms and improve chemotherapeutic effect in patient-derived models of MCP. Mucolysis was achieved using a combination of bromelain (BRO) and N-acetylcysteine (NAC). Ex vivo experiments of mucolysis and chemotherapeutic drug delivery/effect were conducted with MCP and non-MCP tissue explants. In vivo experiments were performed in mouse and rat patient-derived xenograft (PDX) models of early and late (advanced) MCP. MCP tumor explants were less chemosensitive than non-MCP explants. Chronic IP administration of BRO + NAC in a mouse PDX model of early MCP and a rat PDX model of late (advanced) MCP converted solid mucinous tumors into mucinous ascites (mucolysis) that could be drained via a percutaneous catheter (rat model only), significantly reduced solid mucinous tumor growth and improved the efficacy of chemotherapeutic drugs. Combination of BRO + NAC efficiently lyses extracellular mucus in clinically relevant models of MCP. Conversion of solid mucinous tumors into mucinous ascites decreases tumor bulk and allows for minimally invasive drainage of liquified tumors. Lysis of extracellular mucus removes the protective mucinous coating surrounding cancer cells and improves chemotherapeutic drug delivery/efficacy in cancer cells. Our data provide a preclinical rationale for the clinical evaluation of BRO + NAC as a therapeutic strategy for MCP.

In-vitro antibacterial effect of tea polyphenols combined with common antibiotics on multidrug-resistant Klebsiella pneumoniae.

To investigate the bactericidal effect of tea polyphenols on multidrug resistant Klebsiella pneumoniae and its antibacterial efficacy in combination with common antibiotics, and to explore its mechanism. The VITEK 2 Compact automatic microbial identification system was used to identify 20 strains of Klebsiella pneumoniae isolated from clinical isolates. The KB method was used to detect sensitivity of common drugs such as imipenem, piperacillin, piperacillin/tazobactam and cefepime, cefotaxime and ceftazidime; agar dilution method was used for detection of minimum inhibitory concentration (MIC) of tea polyphenols; the variation of the diameter of the antibacterial ring after different concentrations (0.25 MIC, 0.5 MIC) of tea polyphenols in combination with commonly used antibacterial drugs was detected to judge the feasibility of the inhibition of the multidrug-resistant Klebsiella pneumoniae by the combination of tea polyphenols and commonly used antibacterial drugs. Congo red and crystal violent staining was used to detect the impact on bacterial biofilm formation and extracellular mucus-like substance (slime). The K-B values of 20 strains of Klebsiella pneumoniae against common antibiotics were 6-14 mm; the MIC of tea polyphenols against 20 strains of multi-drug resistant Klebsiella pneumoniae was 1024 ug/mL; 0.5 MIC tea polyphenols can increase the diameter of the bacteriostatic ring of imipenem, piperacillin, piperacillin/tazobactam, cefepime, cefotaxime and ceftazidime by 3-28 mm. Tea polyphenols at sub-inhibitory concentrations significantly inhibited the production of Klebsiella pneumoniae biofilm and extracellular mucus (slime). Tea polyphenols could be used in combination with commonly used antibiotics (imipenem, piperacillin, piperacillin/tazobactam, cefepime, cefotaxime and ceftazidime) against multidrug-resistant Klebsiella pneumoniae. It has a synergistic bactericidal effect and affects the formation of bacterial outer membrane and the production of extracellular slime-like substances (slime).

Mucins and the Microbiome.

Generating the barriers that protect our inner surfaces from bacteria and other challenges requires large glycoproteins called mucins. These come in two types, gel-forming and transmembrane, all characterized by large, highly O-glycosylated mucin domains that are diversely decorated by Golgi glycosyltransferases to become extended rodlike structures. The general functions of mucins on internal epithelial surfaces are to wash away microorganisms and, even more importantly, to build protective barriers. The latter function is most evident in the large intestine, where the inner mucus layer separates the numerous commensal bacteria from the epithelial cells. The host's conversion of MUC2 to the outer mucus layer allows bacteria to degrade the mucin glycans and recover the energy content that is then shared with the host. The molecular nature of the mucins is complex, and how they construct the extracellular complex glycocalyx and mucus is poorly understood and a future biochemical challenge.

Laboratory investigations of the role of biofilms on stream‐bed surfaces in debris‐flow runout

AbstractDebris‐flow runout is a fascinating process to understand due to its implications for downstream alluvial fans. Based on the propagation‐deposition behaviors of the Dongyuege (DYG) debris flow, in Yunnan, the effect of biofilms on channel surfaces on debris‐flow runout is investigated in laboratory flumes with two different internal surfaces: surfaces are lined with granite slabs (Model I) and gravel (Model II), respectively.Our results show that biofilms can significantly reduce frictional resistance to flows. They increase flow velocities, slow down the deceleration of the snouts, prolong runout distances, and subsequently extend the areas covered with resulting deposits, thus greatly assisting the propagation of experimental debris flows. Slippery biofilms consisting mainly of diatoms and their extracellular mucus (ECM) reduce the contact friction between the flume‐beds and the overlying fluids, and greatly promote the propagation of tested flows.Well‐developed biofilms are found on the underwater channel surfaces of the DYG Creek. Acting as lubricating layers, they likely played a key role in the DYG debris‐flow runout. Most of the debris transported during the DYG event was deposited on overbanks, and the sediment that caused the disaster was transported to the populated fan region through the stream‐bed clad in the thick biofilms. Owing to their impacts on the development and width of the temporary debris dam breach, the stream‐bed covered with biofilms became a direct contributor to the debris‐flow hazard.Because of the ubiquitous presence of biofilms on mountain stream‐bed surfaces, the development of perennial streamflows can be viewed as an indicator of gully susceptibility to debris flows threatening creek fans. The underwater areas of pre‐event channel cross‐sections should be regarded as slip or low‐friction boundaries, and the parts above stream‐levels can be viewed as no‐slip boundaries. © 2019 John Wiley & Sons, Ltd.