Sulfomucins in the human body

Squaramide-based receptors in anion supramolecular chemistry: insights into anion binding, sensing, transport and extraction

Over the last 15 years, squaramide-based receptors have attracted the attention of supramolecular chemists working in the field of anion recognition. Herein, we highlight examples of squaramide-based receptors that are able to bind, sense, extract and transport anions.

Anion-templated synthesis of a switchable fluorescent [2]catenane with sulfate sensing capability

Anion templation strategies have facilitated the synthesis of various catenane and rotaxane hosts capable of strong and selective binding of anions in competitive solvents. However, this approach has primarily relied on positively charged precursors, limiting the structural diversity and the range of potential applications of the anion-templated mechanically interlocked molecules. Here we demonstrate the synthesis of a rare electroneutral [2]catenane using a powerful, doubly charged sulfate template and a complementary diamidocarbazole-based hydrogen bonding precursor. Owing to the unique three-dimensional hydrogen bonding cavity and the embedded carbazole fluorophores, the resulting catenane receptor functions as a sensitive fluorescent turn-ON sensor for the highly hydrophilic sulfate, even in the presence of a large excess of water. Importantly, the [2]catenane exhibits enhanced binding affinity and selectivity for sulfate over its parent macrocycle and other acyclic diamidocarbazole-based receptors. We demonstrate also, for the first time, that the co-conformation of the catenane may be controlled by reversible acid/base induced protonation and deprotonation of the anionic template, SO42-. This approach pioneers a new strategy to induce molecular motion of interlocked components using switchable anionic templates.

Patients with oral lichen planus display lower levels of salivary acidic glycoproteins than individuals without oral mucosal disease

OBJECTIVES

Salivary proteins, acidic glycoproteins, and free calcium might take part in oral mucosal defence against inflammation in oral lichen planus (OLP). The study aimed to investigate whether the levels of sulfated and sialylated glycoproteins, total protein, and free calcium in saliva from patients with OLP differ from those of individuals without oral mucosal diseases.

MATERIAL AND METHODS

Patients diagnosed with OLP (n = 25) and two control groups without any oral mucosal disease; age- and gender-matched controls (n = 25, 65.6 ± 2.9 years), and younger controls (n = 25, 41.8 ± 2.5 years) were included. Subjective dry mouth (xerostomia) was assessed by asking a single-item question. Chew-stimulated whole saliva was collected to measure sulfated and sialylated glycoproteins by the Alcian Blue method. The total protein was determined spectrophotometrically, and the free calcium measured using an electrode.

RESULTS

The output of salivary sulfated and sialylated glycoproteins in the OLP group (21.8 ± 2.4 µg/min) was lower than in the age- and gender-matched controls (43.0 ± 2.9 µg/min, p = 0.0002), whereas the total protein and calcium output did not differ between the three groups (p > 0.05). The prevalence of xerostomia was significantly higher in the OLP group compared to both control groups (p = 0.038).

CONCLUSIONS

Patients with OLP showed a high prevalence of xerostomia and lower levels of salivary acidic type glycoproteins compared to the individuals without oral mucosa disease.

CLINICAL RELEVANCE

It is relevant to investigate the role of acidic glycoproteins in the pathogenesis of OLP.

Bis[squaramido]ferrocenes as electrochemical sulfate receptors

The bis[squaramido]ferrocene scaffold is introduced and shown to selectively bind and electrochemically report sulfate in competitive water/DMSO mixtures.

Fluorescence Recognition of Anions Using a Heteroditopic Receptor: Homogenous and Two-Phase Sensing

In contrast to monotopic receptor 3, the anthracene functionalized squaramide dual-host receptor 1 is capable of selectively extracting sulfate salts, as was evidenced unambiguously by DOSY, mass spectrometry, fluorescent and ion chromatography measurements. The receptors were investigated in terms of anion and ion pair binding using the UV-vis and 1H NMR titrations method in acetonitrile. The reference anion receptor 3, lacking a crown ether unit, was found to lose the enhancement in anion binding induced by the presence of cations. Besides the ability to bind anions in an enhanced manner exhibited by ion pair receptors 2 and 4, changing the 1-aminoanthracene substituent resulted in their exhibiting a lower anion affinity than receptor 1. By using receptor 1 and adjusting the water content in organic phase it was possible to selectively detect sulfates both by "turn-off" and "turn-on" fluorescence, and to do so homogenously and under interfacial conditions. Such properties of receptor 1 have allowed the development of a new type of sensor capable of recognizing and extracting potassium sulfate from the aqueous medium across a phase boundary, resulting in an appropriate fluorescent response in the organic solution.

Pathogenicity and virulence of Bordetella pertussis and its adaptation to its strictly human host

The highly contagious whooping cough agent Bordetella pertussis has evolved as a human-restricted pathogen from a progenitor which also gave rise to Bordetella parapertussis and Bordetella bronchiseptica. While the latter colonizes a broad range of mammals and is able to survive in the environment, B. pertussis has lost its ability to survive outside its host through massive genome decay. Instead, it has become a highly successful human pathogen by the acquisition of tightly regulated virulence factors and evolutionary adaptation of its metabolism to its particular niche. By the deployment of an arsenal of highly sophisticated virulence factors it overcomes many of the innate immune defenses. It also interferes with vaccine-induced adaptive immunity by various mechanisms. Here, we review data from invitro, human and animal models to illustrate the mechanisms of adaptation to the human respiratory tract and provide evidence of ongoing evolutionary adaptation as a highly successful human pathogen.

Tripodal, Squaramide-Based Ion Pair Receptor for Effective Extraction of Sulfate Salt

Combining three features-the high affinity of squaramides toward anions, cooperation in ion pair binding and preorganization of the binding domains in the tripodal platform-led to the effective receptor 2. The lack of at least one of these key elements in the structures of reference receptors 3 and 4 caused a lower affinity towards ion pairs. Receptor 2 was found to form an intramolecular network in wet chloroform, which changed into inorganic-organic associates after contact with ions and allowed salts to be extracted from an aqueous to an organic phase. The disparity in the binding mode of 2 with sulfates and with other monovalent anions led to the selective extraction of extremely hydrated sulfate anions in the presence of more lipophilic salts, thus overcoming the Hofmeister series.

Mobility shift-based electrophoresis coupled with fluorescent detection enables real-time enzyme analysis of carbohydrate sulfatase activity

Sulfated carbohydrate metabolism is a fundamental process, which occurs in all domains of life. Carbohydrate sulfatases are enzymes that remove sulfate groups from carbohydrates and are essential to the depolymerisation of complex polysaccharides. Despite their biological importance, carbohydrate sulfatases are poorly studied and challenges remain in accurately assessing the enzymatic activity, specificity and kinetic parameters. Most notably, the separation of desulfated products from sulfated substrates is currently a time-consuming process. In this paper, we describe the development of rapid capillary electrophoresis coupled to substrate fluorescence detection as a high-throughput and facile means of analysing carbohydrate sulfatase activity. The approach has utility for the determination of both kinetic and inhibition parameters and is based on existing microfluidic technology coupled to a new synthetic fluorescent 6S-GlcNAc carbohydrate substrate. Furthermore, we compare this technique, in terms of both time and resources, to high-performance anion exchange chromatography and NMR-based methods, which are the two current 'gold standards' for enzymatic carbohydrate sulfation analysis. Our study clearly demonstrates the advantages of mobility shift assays for the quantification of near real-time carbohydrate desulfation by purified sulfatases, and will support the search for small molecule inhibitors of these disease-associated enzymes.

Repulsive Backbone-Backbone Interactions Modulate Access to Specific and Unspecific Binding Sites on Surface-Bound Mucins

Mucin glycoproteins are the matrix-forming key components of mucus, the innate protective barrier protecting us from pathogenic attack. However, this barrier is constantly challenged by mucin-degrading enzymes, which tend to target anionic glycan chains such as sulfate groups and sialic acid residues. Here, we demonstrate that the efficiency of both unspecific and specific binding of small molecules to mucins is reduced when sulfate groups are enzymatically removed from mucins; this is unexpected because neither of the specific mucin-binding partners tested here targets these sulfate motifs on the mucin glycoprotein. Based on simulation results obtained from a numerical model of the mucin macromolecule, we propose that anionic motifs along the mucin chain establish intramolecular repulsion forces which maintain an elongated mucin conformation. In the absence of these repulsive forces, the mucin seems to adopt a more compacted structure, in which the accessibility of several binding sites is restricted. Our results contribute to a better understanding on how different glycans contribute to the broad spectrum of functions mucin glycoproteins have.

Cooperative Transport and Selective Extraction of Sulfates by a Squaramide-Based Ion Pair Receptor: A Case of Adaptable Selectivity

The use of a squaramide-based ion pair receptor offers a solution to the very challenging problem of extraction and transport of extremely hydrated sulfate salt. Herein we demonstrate for the first time that a neutral receptor is able not only to selectively extract but also to transport sulfates in the form of an alkali metal salt across membranes and to do so in a cooperative manner while overcoming the Hofmeister bias. This was made possible by an enhancement in anion binding promoted by cation assistance and by diversifying the stoichiometry of receptor complexes with sulfates and other ions. The existence of a peculiar 4:1 complex of receptor 2 with sulfates in solution was confirmed by UV-vis and 1H NMR titration experiments, DOSY and DLS measurements, and supported by solid-state X-ray measurements. By varying the separation technique and experimental conditions, it was possible to switch the depletion of the aqueous layer into extremely hydrophilic or less lipophilic salts, thus obtaining the desired selectivity.

Benzenebistriazole-strapped calix[4]pyrrole: a neutral anion receptor with CH and NH donor groups that exhibits high sulfate binding affinity and selectivity in aqueous solutions

A calix[4]pyrrole strapped by benzenebistriazole has been prepared as an artificial anion binding receptor. This neutral anion receptor shows high sulfate binding affinity and selectivity in an aqueous solution. In solid state, the receptor binds the sulfate anion in a chair-like 3D cavity via multiple N-H and C-H hydrogen bonds.

The Effect of Antioxidant Agents on Cisplatin-Induced Laryngeal Histological Alterations in Rats

The larynx-related adverse effects that depend on cisplatin decrease patient comfort and many antioxidants have been used to eliminate these side effects. We aimed to identify the laryngeal mucosal changes imposed by cisplatin and investigated whether antioxidants, and their healing effects on these changes, may help reduce laryngeal complications in patients resulting from adverse effects in the larynx. A rat model was designed to evaluate the effects of cisplatin on the larynx and the protective role of antioxidants. Single-dose cisplatin was given both intraperitoneally alone and additionally administered with p-coumaric acid, melatonin, resveratrol, vitamin D, and oleic acid over 5 days. Whole larynges were dissected and evaluated histologically, histochemically, and immunohistochemically. Varying degrees of mucosal changes cisplatin group, but neither erosion nor an ulcer was observed. Numerous variable histological effects of antioxidants were observed on cisplatin exposed laryngeal mucosa. The most obvious effects of cisplatin were edema. The results of the study showed that resveratrol was the most preventive antioxidant agent against cisplatin-dependent mucosal changes. The highest increase in the Ki67 index was in the oleic acid group. Vitamin D increased stromal cyclooxygenase-2 expression that may have an effect on increasing mucosal damage.

Host responses to Clostridium perfringens challenge in a chicken model of chronic stress

Background

This study utilized a chicken model of chronic physiological stress mediated by corticosterone (CORT) administration to ascertain how various host metrics are altered upon challenge with Clostridium perfringens. Necrotic enteritis (NE) is a disease of the small intestine of chickens incited by C. perfringens, which can result in elevated morbidity and mortality. The objective of the current study was to investigate how physiological stress alters host responses and predisposes birds to subclinical NE.

Results

Birds administered CORT exhibited higher densities of C. perfringens in their intestine, and this corresponded to altered production of intestinal mucus. Characterization of mucus showed that C. perfringens treatment altered the relative abundance of five glycans. Birds inoculated with C. perfringens did not exhibit evidence of acute morbidity. However, histopathologic changes were observed in the small intestine of infected birds. Birds administered CORT showed altered gene expression of tight junction proteins (i.e. CLDN3 and CLDN5) and toll-like receptors (i.e. TLR2 and TLR15) in the small intestine. Moreover, birds administered CORT exhibited increased expression of IL2 and G-CSF in the spleen, and IL1β, IL2, IL18, IFNγ, and IL6 in the thymus. Body weight gain was impaired only in birds that were administered CORT and challenged with C. perfringens.

Conclusion

CORT administration modulated a number of host functions, which corresponded to increased densities of C. perfringens in the small intestine and weight gain impairment in chickens. Importantly, results implicate physiological stress as an important predisposing factor to NE, which emphasizes the importance of managing stress to optimize chicken health.

Ion-pair induced supramolecular assembly formation for selective extraction and sensing of potassium sulfate

Selective extraction of sulfates in the form of alkali metal salts using charge-neutral molecular receptors is one of the holy grails of supramolecular chemistry. Herein we describe, for the first time, a squaramide-based ion pair receptor equipped with a crown ether site that is able to extract potassium sulfate from the aqueous to the organic phase (an analogous monotopic anion receptor lacking the crown ether unit lacks this ability). 1H NMR, UV-vis, DOSY-NMR, DLS, and MS experiments and the solid-state single crystal structure provided evidence of the formation of a supramolecular core-shell like assembly upon interaction of the receptor with potassium sulfate. The presence of monovalent potassium salts, in contrast, promoted the formation of simple 1 : 1 complexes. Unlike the 4 : 1 assembly, the 1 : 1 complexes are poorly soluble in organic media. This feature was utilized to overcome the Hofmeister bias and allow for selective extraction of extremely hydrophilic sulfates over lipophilic nitrate anions, which was unambiguously proved by quantitative AES and ion chromatography measurements. A simple modification of the receptor structure led to a "naked eye" optical sensor able to selectively detect sulfates under both SLE and LLE conditions.

Receptors for sulfate that function across a wide pH range in mixed aqueous-DMSO media

Water soluble squaramide macrocycles (MSQs) display high sulfate binding affinities in aqueous DMSO mixtures. The introduction of pyridine spacers into the macrocycles resulted in increased sulfate binding affinity in comparison to compounds with benzene spacers. [3]MSQ 6 was found to be a selective ligand for SO42- in highly competitive conditions and over a wide pH range (3.2-14).

Analysis of A4gnt Knockout Mice Reveals an Essential Role for Gastric Sulfomucins in Preventing Gastritis Cystica Profunda

Gastric adenocarcinoma cells secrete sulfomucins, but their role in gastric tumorigenesis remains unclear. To address that question, we generated A4gnt/Chst4 double-knockout (DKO) mice by crossing A4gnt knockout (KO) mice, which spontaneously develop gastric adenocarcinoma, with Chst4 KO mice, which are deficient in the sulfotransferase GlcNAc6ST-2. A4gnt/Chst4 DKO mice lack gastric sulfomucins but developed gastric adenocarcinoma. Unexpectedly, severe gastric erosion occurred in A4gnt/Chst4 DKO mice at as early as 3 weeks of age, and with aging these lesions were accompanied by gastritis cystica profunda (GCP). Cxcl1, Cxcl5, Ccl2, and Cxcr2 transcripts in gastric mucosa of 5-week-old A4gnt/Chst4 DKO mice exhibiting both hyperplasia and severe erosion were significantly upregulated relative to age-matched A4gnt KO mice, which showed hyperplasia alone. However, upregulation of these genes disappeared in 50-week-old A4gnt/Chst4 DKO mice exhibiting high-grade dysplasia/adenocarcinoma and GCP. Moreover, Cxcl1 and Cxcr2 were downregulated in A4gnt/Chst4 DKO mice relative to age-matched A4gnt KO mice exhibiting adenocarcinoma alone. These combined results indicate that the presence of sulfomucins prevents severe gastric erosion followed by GCP in A4gnt KO mice by transiently regulating a set of inflammation-related genes, Cxcl1, Cxcl5, Ccl2, and Cxcr2 at 5 weeks of age, although sulfomucins were not directly associated with gastric cancer development.

Metabolic functions of the human gut microbiota: the role of metalloenzymes

Covering: up to the end of 2017 The human body is composed of an equal number of human and microbial cells. While the microbial community inhabiting the human gastrointestinal tract plays an essential role in host health, these organisms have also been connected to various diseases. Yet, the gut microbial functions that modulate host biology are not well established. In this review, we describe metabolic functions of the human gut microbiota that involve metalloenzymes. These activities enable gut microbial colonization, mediate interactions with the host, and impact human health and disease. We highlight cases in which enzyme characterization has advanced our understanding of the gut microbiota and examples that illustrate the diverse ways in which metalloenzymes facilitate both essential and unique functions of this community. Finally, we analyze Human Microbiome Project sequencing datasets to assess the distribution of a prominent family of metalloenzymes in human-associated microbial communities, guiding future enzyme characterization efforts.

Fantastic voyage: the journey of intestinal microbiota-derived microvesicles through the body

As part of their life cycle, Gram-negative bacteria produce and release microvesicles (outer membrane vesicles, OMVs) consisting of spherical protrusions of the outer membrane that encapsulate periplasmic contents. OMVs produced by commensal bacteria in the gastrointestinal (GI) tract of animals are dispersed within the gut lumen with their cargo and enzymes being distributed across and throughout the GI tract. Their ultimate destination and fate is unclear although they can interact with and cross the intestinal epithelium using different entry pathways and access underlying immune cells in the lamina propria. OMVs have also been found in the bloodstream from which they can access various tissues and possibly the brain. The nanosize and non-replicative status of OMVs together with their resistance to enzyme degradation and low pH, alongside their ability to interact with the host, make them ideal candidates for delivering biologics to mucosal sites, such as the GI and the respiratory tract. In this mini-review, we discuss the fate of OMVs produced in the GI tract of animals with a focus on vesicles released by Bacteroides species and the use of OMVs as vaccine delivery vehicles and other potential applications.

Capillary Electrophoresis Analysis of Bovine Milk Oligosaccharides Permits an Assessment of the Influence of Diet and the Discovery of Nine Abundant Sulfated Analogues

Bovine milk oligosaccharides (BMOs), like their analogues in human milk, have important prebiotic functions. Environmental factors have previously been linked to variation in BMO structures, and thus to test the hypothesis that the bovine diet may lead to these changes in relative BMO abundances, a rapid capillary electrophoresis (CE)-based work flow was developed to profile the BMOs extracted from the milk of cows fed distinctly different diets. Over the first week of lactation, few significant differences were observed between the different diet groups, with the dominant changes being clearly linked to lactation period. CE analyses indicated the presence of ten unusually anionic BMOs, which were predicted to be phosphorylated and sulfated species. Nine unique sulfated BMOs were detected by high-resolution accurate mass spectrometry, none of which have been previously described in bovine milk. The biosynthesis of these was in direct competition with 3'-sialyllactose, the most abundant BMO in bovine milk.

Selective turn-on fluorescence sensing of sulfate in aqueous-organic mixtures by an uncharged bis(diamidocarbazole) receptor

A linear, uncharged, hydrogen bonding receptor A with two carbazole-based binding domains was synthesised and evaluated for its anion binding properties in DMSO/H₂O mixtures. ¹H NMR titrations revealed that, in DMSO/H₂O 0.5%, A forms both 1 : 1 and 1 : 2 complexes with SO₄^2-, H₂PO₄^-, PhCOO^- and Cl^-. In 1 : 1 complexes the receptor encloses the tetrahedral anions tightly, forming a helical structure, while Cl^- binds with a single carbazole unit only. In the presence of 10% of water the 1 : 2 complexes with SO₄^2- and PhCOO^- disappear, and the respective 1 : 1 binding constants decrease sufficiently to be quantified by UV-Vis titration. In this highly competitive medium, A binds sulfate with K_1:1 = 10^5.47 M^-1, i.e., it binds approx. 30, 360 and >1000 times more strongly than H₂PO₄^-, PhCOO^- and Cl^-, respectively. Furthermore, the association with sulfate is over 50 times stronger than that for a model diamidocarbazole 1 under identical conditions, suggesting a very strong chelating effect due to the diglycoyl linker. Increasing the amount of water to 25% (the solubility limit of A) lowers the 1 : 1 binding constant with SO₄^2- to 10^3.73 M^-1. Receptor A was shown to act as a selective turn-on fluorescent sensor for sulfate, able to sense sulfate in sulfate-rich mineral water.

An Ideal C3-Symmetric Sulfate Complex: Molecular Recognition of Oxoanions by m-Nitrophenyl- and Pentafluorophenyl-Functionalized Hexaurea Receptors

The anion-binding properties of two tripodal-based hexaureas appended with the m-nitrophenyl (1) and pentafluorophenyl (2) groups have been studied both experimentally and theoretically, showing strong affinities for sulfate over other inorganic oxoanions such as hydrogen sulfate, dihydrogen phosphate, bicarbonate, nitrate, and perchlorate. The structural analysis of the sulfate complex with 1 reveals that the receptor organizes all urea-binding sites toward the cavity at precise orientations around a tetrahedral sulfate anion to form an ideal C₃-symmetric sulfate complex that is stabilized by 12 hydrogen-bonding interactions. The receptor and the encapsulated sulfate are located on the threefold axis passing through the bridgehead nitrogen of 1 and the sulfur atom of the anionic guest. The high-level density functional theory calculations support the crystallographic results, demonstrating that the C₃-symmetric conformation of the sulfate complex is achieved due to the complementary NH···O between the receptor and sulfate.

The NAG Sensor NagC Regulates LEE Gene Expression and Contributes to Gut Colonization by Escherichia coli O157:H7

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 are human pathogens responsible for bloody diarrhea and renal failures. EHEC employ a type 3 secretion system to attach directly to the human colonic epithelium. This structure is encoded by the locus of enterocyte effacement (LEE) whose expression is regulated in response to specific nutrients. In this study, we show that the mucin-derived sugars N-acetylglucosamine (NAG) and N-acetylneuraminic acid (NANA) inhibit EHEC adhesion to epithelial cells through down-regulation of LEE expression. The effect of NAG and NANA is dependent on NagC, a transcriptional repressor of the NAG catabolism in E. coli. We show that NagC is an activator of the LEE1 operon and a critical regulator for the colonization of mice intestine by EHEC. Finally, we demonstrate that NAG and NANA as well as the metabolic activity of Bacteroides thetaiotaomicron affect the in vivo fitness of EHEC in a NagC-dependent manner. This study highlights the role of NagC in coordinating metabolism and LEE expression in EHEC and in promoting EHEC colonization in vivo.

Macrocyclic squaramides: anion receptors with high sulfate binding affinity and selectivity in aqueous media

A number of macrocyclic squaramide-containing receptors (MSQs) have been designed and synthesised and their interaction with a range of inorganic anions was studied in solution by ¹H NMR spectroscopy and ESI-HRMS. The binding data revealed remarkable binding of sulfate in aqueous mixtures from 0.5 to 50% v/v H₂O/DMSO-d₆. The larger [3]-MSQs were found to better match the size and shape of the sulfate ion than the [2]-MSQs, providing high affinity and selectivity for sulfate while other tetrahedral divalent anions such as selenate, phosphate species and chromate have substantially lower binding affinities. In mixtures of anions mimicking the composition of either nuclear waste or plasma, the [3]-MSQs were still able to bind sulfate ions with high affinity.

Low crude protein diets modulate intestinal responses in weaned pigs challenged with Escherichia coli K88

Opapeju, F. O., Rodriguez-Lecompte, J. C., Rademacher, M., Krause, D. O. and Nyachoti, C. M. 2015. Low crude protein diets modulate intestinal responses in weaned pigs challenged with Escherichia coli K88. Can. J. Anim. Sci. 95: 71–78. Effects of dietary crude protein (CP) content on intestinal indicators of infection and diarrhea in pigs challenged with enterotoxigenic Escherichia coli (ETEC) K88 were investigated. Forty piglets [body weight (BW)=6.96±0.45, mean±SD], housed four per pen, were randomly allotted to two diets (five pens per diet): a 22.2% CP or a 17.3% CP supplemented with amino acids. Diets contained the same amount of standardized ileal digestible Lys, Met+Cys, Thr, Trp based on the ideal amino acid ratio. Isoleucine and Val were added to the 17.3% CP diet up to the level in the 22.2% CP diet. All other nutrients were as per National Research Council (1998) specification. Three piglets per pen were serially slaughtered on days 3, 5, and 7 after weaning for evaluation of intestinal hydrolases (data reported elsewhere). On day 8 post-weaning, the remaining pigs were inoculated with 6 mL of ETEC suspension (1010 CFU mL−1) and slaughtered 20 h later. Mucosal-associated ETEC was detected in higher counts (3.17±0.63 log10 CFU g−1 digesta) in 80% of pigs fed the 22.2% CP diet compared with 20% of those fed the 17.3% CP diet in which the counts were also lower (2.00±log10 CFU g−1 digesta). Pigs fed the 22.2% CP diet tended (P=0.09) to have fewer goblet cells with sialomucins in jejunal villi compared with those fed the 17.3% CP diet. The expression of toll-like receptors 4 and 5 was unaffected by diet but the expression of sodium-coupled glucose transporter 1 was higher (P=0.04) in the jejunum of pigs fed the 22.2% CP diet compared with those fed the 17.3% CP diet. The results suggest that feeding a low-CP diet decreases ETEC proliferation and attachment in the intestinal mucosa and this is accompanied by a reduced expression of sodium-coupled glucose transporter 1.

Genome analysis of Flaviramulus ichthyoenteri Th78(T) in the family Flavobacteriaceae: insights into its quorum quenching property and potential roles in fish intestine

Background

Intestinal microbes play significant roles in fish and can be possibly used as probiotics in aquaculture. In our previous study, Flaviramulus ichthyoenteri Th78^T, a novel species in the family Flavobacteriaceae, was isolated from fish intestine and showed strong quorum quenching (QQ) ability. To identify the QQ enzymes in Th78^T and explore the potential roles of Th78^T in fish intestine, we sequenced the genome of Th78^T and performed extensive genomic analysis.

Results

An N-acyl homoserine lactonase FiaL belonging to the metallo-β-lactamase superfamily was identified and the QQ activity of heterologously expressed FiaL was confirmed in vitro. FiaL has relatively little similarity to the known lactonases (25.2 ~ 27.9% identity in amino acid sequence). Various digestive enzymes including alginate lyases and lipases can be produced by Th78^T, and enzymes essential for production of B vitamins such as biotin, riboflavin and folate are predicted. Genes encoding sialic acid lyases, sialidases, sulfatases and fucosidases, which contribute to utilization of mucus, are present in the genome. In addition, genes related to response to different stresses and gliding motility were also identified. Comparative genome analysis shows that Th78^T has more specific genes involved in carbohydrate transport and metabolism compared to other two isolates in Flavobacteriaceae, both isolated from sediments.

Conclusions

The genome of Th78^T exhibits evident advantages for this bacterium to survive in the fish intestine, including production of QQ enzyme, utilization of various nutrients available in the intestine as well as the ability to produce digestive enzymes and vitamins, which also provides an application prospect of Th78^T to be used as a probiotic in aquaculture.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1275-0) contains supplementary material, which is available to authorized users.

Influences of the colonic microbiome on the mucous gel layer in ulcerative colitis

The colonic mucus gel layer (MGL) is a critical component of the innate immune system acting as a physical barrier to microbes, luminal insults, and toxins. Mucins are the major component of the MGL. Selected microbes have the potential to interact with, bind to, and metabolize mucins. The tolerance of the host to the presence of these microbes is critical to maintaining MGL homeostasis. In disease states such as ulcerative colitis (UC), both the mucosa associated microbes and the constituent MGL mucins have been shown to be altered. Evidence is accumulating that implicates the potential for mucin degrading bacteria to negatively impact the MGL and its stasis. These effects appear more pronounced in UC.   This review is focused on the host-microbiome interactions within the setting of the MGL. Special focus is given to the mucolytic potential of microbes and their interactions in the setting of the colitic colon.

Role of sulphate in development

Sulphate contributes to numerous processes in mammalian physiology, particularly during development. Sulphotransferases mediate the sulphate conjugation (sulphonation) of numerous compounds, including steroids, glycosaminoglycans, proteins, neurotransmitters and xenobiotics, transforming their biological activities. Importantly, the ratio of sulphonated to unconjugated molecules plays a significant physiological role in many of the molecular events that regulate mammalian growth and development. In humans, the fetus is unable to generate its own sulphate and therefore relies on sulphate being supplied from maternal circulation via the placenta. To meet the gestational needs of the growing fetus, maternal blood sulphate concentrations double from mid-gestation. Maternal hyposulphataemia has been linked to fetal sulphate deficiency and late gestational fetal loss in mice. Disorders of sulphonation have also been linked to a number of developmental disorders in humans, including skeletal dysplasias and premature adrenarche. While recognised as an important nutrient in mammalian physiology, sulphate is largely unappreciated in clinical settings. In part, this may be due to technical challenges in measuring sulphate with standard pathology equipment and hence the limited findings of perturbed sulphate homoeostasis affecting human health. This review article is aimed at highlighting the importance of sulphate in mammalian development, with basic science research being translated through animal models and linkage to human disorders.

Mucin-type O-glycans and their roles in intestinal homeostasis

Mucin-type O-glycans are the primary constituents of mucins that are expressed on various mucosal sites of the body, especially the bacteria-laden intestinal tract. Mucins are the main components of mucus, which is secreted by goblet cells and forms a protective homeostatic barrier between the resident microbiota and the underlying immune cells in the colon. However, the specific role of mucin-type O-glycans in mucus barrier function has been uncertain. Recent studies utilizing mice deficient in key glycosyltransferases involved in O-glycan biosynthesis on intestinal mucins have underscored the importance of mucin-type O-glycosylation in mucus barrier function. This review will highlight recent advances in our understanding of mucin-type O-glycan function in the mucus barrier and how they promote mutualism with our resident microbiota.

Mucin-Related Molecular Responses of Bronchial Epithelial Cells in Rats Infected with the Nematode Nippostrongylus brasiliensis

Although mucins are essential for the protection of internal epithelial surfaces, molecular responses involving mucin production and secretion in response to various infectious agents in the airway have not been fully elucidated. The present study analysed airway goblet cell mucins in rats infected with the nematode Nippostrongylus brasiliensis, which migrates to the lungs shortly after infection. Goblet cell hyperplasia occurred in the bronchial epithelium 3-10 days after infection. The high iron diamine-alcian blue staining combined with neuraminidase treatment showed that sialomucin is the major mucin in hyperplastic goblet cells. Immunohistochemical studies demonstrated that goblet cell mucins were immunoreactive with both the major airway mucin core peptide, Muc5AC, and the major intestinal mucin core peptide Muc2. Reverse transcription real-time PCR studies demonstrated upregulation of gene transcription levels of Muc5AC, Muc2, the sialyltransferase St3gal4, and the resistin-like molecule beta (Retnlb) in the lungs. These results showed that nematode infection induces airway epithelial responses characterised by the production of sialomucin with Muc5AC and Muc2 core peptides. These mucins, as well as Retnlb, might have important roles in the protection of mucosa from migrating nematodes in the airway.

Structural basis for promiscuity and specificity during Candida glabrata invasion of host epithelia

The human pathogenic yeast Candida glabrata harbors more than 20 surface-exposed, epithelial adhesins (Epas) for host cell adhesion. The Epa family recognizes host glycans and discriminates between target tissues by their adhesin (A) domains, but a detailed structural basis for ligand-binding specificity of Epa proteins has been lacking so far. In this study, we provide high-resolution crystal structures of the Epa1A domain in complex with different carbohydrate ligands that reveal how host cell mucin-type O-glycans are recognized and allow a structure-guided classification of the Epa family into specific subtypes. Further detailed structural and functional characterization of subtype-switched Epa1 variants shows that specificity is governed by two inner loops, CBL1 and CBL2, involved in calcium binding as well as by three outer loops, L1, L2, and L3. In summary, our study provides the structural basis for promiscuity and specificity of Epa adhesins, which might further contribute to developing anti-adhesive antimycotics and combating Candida colonization.

Inflammatory cues modulate the expression of secretory product genes, Golgi sulfotransferases and sulfomucin production in LS174T cells

The signals that mediate goblet cell expression of specific mucin chemotypes are poorly defined. Animal and in vitro studies show that acidomucin chemotypes may be altered by inflammation and changes in intestinal microbiota. To examine factors that may elicit this response, human adenocarcinoma-derived LS174T cells, which have a goblet cell-like phenotype and produce both sulfo- and sialomucins, were used to examine the effects of selected microbial and host factors on expression of goblet cell secretory product genes, sulfotransferases and sulfomucin production. Expression of genes encoding mucin 2 (MUC2), resistin-like molecule β (RETNLB), and trefoil factor 3 (TFF3) and Golgi sulfotransferases, carbohydrate (N-acetylglucosamine 6-O) sulfotransferase 5 (CHST5) and galactose-3-O-sulfotransferase 2 (GAL3ST2), was measured by quantitative reverse transcriptase-polymerase chain reaction following treatment with bacterial flagellin, tumor necrosis factor α (TNF-α) or the mucogenic cytokine interleukin-13 (IL-13). Expression of the toll-like receptor 5 (TLR5) gene was also analysed. Sulfomucin expression was examined via high-iron diamide/alcian blue (HID/AB) histochemistry and immunofluorescent staining for the Sulfo Le(a) antigen, which is synthesized in part by GAL3ST2. Flagellin, IL-13 and TNF-α all significantly increased GAL3ST2, MUC2, TFF3 and TLR5 expression, while only IL-13 increased RETNLB and CHST5 expression. Based on HID/AB histochemistry, mucin sulfation was significantly increased in response to both flagellin and IL-13 but not TNF-α. Only treatment with flagellin increased the expression of the Sulfo Le(a) antigen. Collectively, these results indicate that bacterial flagellin, IL-13 and TNF-α differentially modulate the expression of goblet cell secretory product genes, sulfotransferases and sulfomucin production.

On the relationship between sialomucin and sulfomucin expression and hydrogenotrophic microbes in the human colonic mucosa

The colonic mucus layer is comprised primarily of acidomucins, which provide viscous properties and can be broadly classified into sialomucins or sulfomucins based on the presence of terminating sialic acid or sulfate groups. Differences in acidomucin chemotypes have been observed in diseases such as colorectal cancer and inflammatory bowel disease, and variation in sialo- and sulfomucin content may influence microbial colonization. For example, sulfate derived from sulfomucin degradation may promote the colonization of sulfate-reducing bacteria (SRB), which through sulfate respiration generate the genotoxic gas hydrogen sulfide. Here, paired biopsies from right colon, left colon, and rectum of 20 subjects undergoing routine screening colonoscopies were collected to enable parallel histochemical and microbiological studies. Goblet cell sialo- and sulfomucins in each biopsy were distinguished histochemically and quantified. Quantitative PCR and multivariate analyses were used to examine the abundance of hydrogenotrophic microbial groups and SRB genera relative to acidomucin profiles. Regional variation was observed in sialomucins and sulfomucins with the greatest abundance of each found in the rectum. Mucin composition did not appear to influence the abundance of SRB or other hydrogenotrophic microbiota but correlated with the composition of different SRB genera. A higher sulfomucin proportion correlated with higher quantities of Desulfobacter, Desulfobulbus and Desulfotomaculum, relative to the predominant Desulfovibrio genus. Thus, acidomucin composition may influence bacterial sulfate respiration in the human colon, which may in turn impact mucosal homeostasis. These results stress the need to consider mucus characteristics in the context of studies of the microbiome that target intestinal diseases.

Pathogenesis of and unifying hypothesis for idiopathic pouchitis

Ileal pouch-anal anastomosis is the procedure of choice in the surgical management of refractory ulcerative colitis. Pouchitis affects up to 60% of patients following ileal pouch-anal anastomosis for ulcerative colitis. It overlaps significantly with ulcerative colitis such that improvements in our understanding of one will impact considerably on the other. The symptoms are distressing and impinge significantly on patients' quality of life. Despite 30 years of scientific and clinical investigation, the pathogenesis of pouchitis is unknown; however, recent advances in molecular and cell biology make a synergistic hypothesis possible. This hypothesis links interaction between epithelial metaplasia, changes in luminal bacteria (in particular sulfate-reducing bacteria), and altered mucosal immunity. Specifically, colonic metaplasia supports colonization by sulfate-reducing bacteria that produce hydrogen sulfide. This causes mucosal depletion and subsequent inflammation. Although in most cases antibiotics lead to bacterial clearance and symptom resolution, immunogenetic subpopulations can develop a chronic refractory variant of pouchitis. The aims of this paper are to discuss proposed pathogenic mechanisms and to describe a novel mechanism that combines many hypotheses and explains several aspects of pouchitis. The implications for the management of both pouchitis and ulcerative colitis are discussed.

Dietary supplementation of resveratrol suppresses colonic tumour incidence in 1,2-dimethylhydrazine-treated rats by modulating biotransforming enzymes and aberrant crypt foci development

Diet-induced changes in the activities of bacterial enzymes are known to play a role in colon cancer development. Resveratrol has been implicated as a protective agent in carcinogenesis. In the present study, the effect of resveratrol on the activities of faecal and colonic biotransforming enzymes such as beta-glucuronidase, beta-glucosidase, beta-galactosidase, mucinase, nitroreductase and faecal sulfatase activity was assessed. The total number of aberrant crypt foci and their distribution in the proximal, medial and distal colon were observed in 1,2-dimethylhydrazine (DMH)-induced rats (group 3) and other treatment groups (groups 4-6). DMH (0.02 g/kg body weight) was given subcutaneously once a week for 15 consecutive weeks, and the experiment was terminated at 30 weeks. DMH-treated rats showed elevated levels of cancer-associated bacterial enzyme activities, whereas on resveratrol supplementation in three different regimens, rats showed lowered activities. Resveratrol supplementation throughout the experimental period (group 6) exerted a more pronounced effect (P < 0.01) by modulating the development of aberrant crypt foci and the activities of bacterial enzymes than did the other treatment regimens (groups 4 and 5). Thus, the present results demonstrate the inhibitory effect of resveratrol on DMH-induced colon carcinogenesis in rats.

Stomach-specific calpain, nCL-2, localizes in mucus cells and proteolyzes the beta-subunit of coatomer complex, beta-COP

Calpain is a Ca2+-regulated cytosolic protease. Mammals have 14 calpain genes, half of which are predominantly expressed in specific organ(s); the rest are expressed ubiquitously. A defect in calpains causes lethality/pathogenicity, indicating their physiological indispensability. nCL-2/calpain-8a was identified as a stomach-specific calpain, whose physiological functions are unclear. To elucidate these, we characterized nCL-2 in detail. Unexpectedly, nCL-2 was localized strictly to the surface mucus cells in the gastric epithelium and the mucus-secreting goblet cells in the duodenum. Yeast two-hybrid screening identified several nCL-2-interacting molecules. Of these, the beta-subunit of coatomer complex (beta-COP) occurs in the stomach pit cells and is proteolyzed by nCL-2 in vitro. Furthermore, beta-COP and nCL-2 co-expressed in COS7 cells co-localized in the Golgi, and Ca2+-ionophore stimulation caused the proteolysis of beta-COP near the linker region, resulting in the dissociation of beta-COP from the Golgi. These results strongly suggest novel functions for nCL-2 that involve the membrane trafficking of mucus cells via interactions with coat protein.

Two domains within the Mycoplasma hyopneumoniae cilium adhesin bind heparin

Mycoplasma hyopneumoniae is the causative agent of porcine enzootic pneumonia, a chronic and economically significant respiratory disease that affects swine production worldwide. M. hyopneumoniae adheres to and adversely affects the function of ciliated epithelial cells of the respiratory tract, and the cilium adhesin (Mhp183, P97) is intricately but not exclusively involved in this process. Although binding of pathogenic bacteria to glycosaminoglycans is a recognized step in pathogenesis, knowledge of glycosaminoglycan-binding proteins in M. hyopneumoniae is lacking. However, heparin and other sulfated polysaccharides are known to block the binding of M. hyopneumoniae to purified swine respiratory cilia. In this study, four regions within the cilium adhesin were examined for the ability to bind heparin. Cilium adhesin fragments comprising 653 amino acids of the N terminus and 301 amino acids of the C terminus (containing two repeat regions, R1 and R2) were cloned and expressed. These fragments bound heparin in a dose-dependent and saturable manner with physiologically significant binding affinities of 0.27 +/- 0.02 microM and 1.89 +/- 0.33 microM, respectively. Heparin binding of both fragments was strongly inhibited by the sulfated polysaccharides fucoidan and mucin but not by chondroitin sulfate B. When the C-terminal repeat regions R1 and R2 were cloned separately and expressed, heparin-binding activity was lost, suggesting that both regions are required for heparin binding. The ability of the cilium adhesin to bind heparin indicates that this molecule plays a multifunctional role in the adherence of M. hyopneumoniae to host respiratory surfaces and therefore has important implications with respect to the pathogenesis of this organism.

A novel mechanism for desulfation of mucin: identification and cloning of a mucin-desulfating glycosidase (sulfoglycosidase) from Prevotella strain RS2

A novel enzyme which may be important in mucin degradation has been discovered in the mucin-utilizing anaerobe Prevotella strain RS2. This enzyme cleaves terminal 2-acetamido-2-deoxy-beta-D-glucopyranoside 6-sulfate (6-SO3-GlcNAc) residues from sulfomucin and from the model substrate 4-nitrophenyl 2-acetamido-2-deoxy-beta-D-glucopyranoside 6-sodium sulfate. The existence of this mucin-desulfating glycosidase (sulfoglycosidase) suggests an alternative mechanism by which this bacterium may desulfate sulfomucins, by glycosidic removal of a sulfated sugar from mucin oligosaccharide chains. Previously, mucin desulfation was thought to take place by the action of a specific desulfating enzyme, which then allowed glycosidases to remove desulfated sugar. Sulfate removal from sulfomucins is thought to be a rate-limiting step in mucin degradation by bacteria in the regions of the digestive tract with a significant bacterial flora. The sulfoglycosidase was induced by growth of the Prevotella strain on mucin and was purified 284-fold from periplasmic extracts. Tryptic digestion and sequencing of peptides from the 100-kDa protein enabled the sulfoglycosidase gene to be cloned and sequenced. Active recombinant enzyme was made in an Escherichia coli expression system. The sulfoglycosidase shows sequence similarity to hexosaminidases. The only other enzyme that has been shown to remove 6-SO3-GlcNAc from glycoside substrates is the human lysosomal enzyme beta-N-acetylhexosaminidase A, point mutations in which cause the inheritable, lysosomal storage disorder Tay-Sachs disease. The human enzyme removes GlcNAc from glycoside substrates also, in contrast to the Prevotella enzyme, which acts on a nonsulfated substrate at a rate that is only 1% of the rate observed with a sulfated substrate.

Sulfatases: Structure, Mechanism, Biological Activity, Inhibition, and Synthetic Utility

Sulfatases, which cleave sulfate esters in biological systems, play a key role in regulating the sulfation states that determine the function of many physiological molecules. Sulfatase substrates range from small cytosolic steroids, such as estrogen sulfate, to complex cell-surface carbohydrates, such as the glycosaminoglycans. The transformation of these molecules has been linked with important cellular functions, including hormone regulation, cellular degradation, and modulation of signaling pathways. Sulfatases have also been implicated in the onset of various pathophysiological conditions, including hormone-dependent cancers, lysosomal storage disorders, developmental abnormalities, and bacterial pathogenesis. These findings have increased interest in sulfatases and in targeting them for therapeutic endeavors. Although numerous sulfatases have been identified, the wide scope of their biological activity is only beginning to emerge. Herein, accounts of the diversity and growing biological relevance of sulfatases are provided along with an overview of the current understanding of sulfatase structure, mechanism, and inhibition.

Interleukin 10-deficient mice exhibit defective colonic Muc2 synthesis before and after induction of colitis by commensal bacteria

Germ-free (GF) interleukin 10-deficient (IL-10) mice develop chronic colitis after colonization by normal enteric bacteria. Muc2 is the major structural component of the protective colonic mucus. Our aim was to determine whether primary or induced aberrations in Muc2 synthesis occur in GF IL-10 mice that develop colitis after bacterial colonization. GF IL-10 and wild-type mice were colonized with commensal bacteria for various intervals up to 6 weeks. Colitis was quantified by histologic score and IL-12 secretion. Muc2 synthesis, total level of Muc2, and Muc2 sulfation were measured quantitatively. GF IL-10 mice showed 10-fold lower Muc2 synthesis and Muc2 levels compared with GF wild-type mice, but Muc2 sulfation was not different. When bacteria were introduced, IL-10 mice developed colitis, whereas wild-type mice remained healthy. Muc2 synthesis was unchanged in wild-type mice, but IL-10 mice showed a peak increase in Muc2 synthesis 1 week after bacterial introduction, returning to baseline levels after 2 weeks. Total Muc2 levels decreased 2-fold in wild-type mice but remained at stable low levels in IL-10 mice. Upon introducing bacteria, Muc2 sulfation increased 2-fold in wild-type mice, whereas in IL-10 mice Muc2 sulfation decreased 10-fold. In conclusion, a primary defect in colonic Muc2 synthesis is present in IL-10 mice, whereas bacterial colonization and colitis in these mice led to reduced Muc2 sulfation. These quantitative and structural aberrations in Muc2 in IL-10 mice likely reduce the ability of their mucosa to cope with nonpathogenic commensal bacteria and may contribute to their susceptibility to develop colitis.

Detection of sulfated glycoproteins in intestinal metaplasia: a comparison of traditional mucin staining with immunohistochemistry for the sulfo-Lewis(a) carbohydrate epitope

BACKGROUND

Premalignant Barrett's oesophagus (BO) and gastric intestinal metaplasia (IM) show phenotypic variability. Incompletely differentiated sulfomucin rich gastric IM (type III) may have increased malignant potential. The types of sulfated oligosaccharide structures present in IM, BO, and colon have not been fully characterised.

AIMS

To compare sulfo-Lewis(a) epitope tissue distribution with high iron diamine (HID) positive sulfomucin in metaplastic, dysplastic, and neoplastic tissues from oesophagus and stomach.

METHODS

Sections containing gastric IM or BO (some associated with dysplasia or adenocarcinoma) were stained by the HID/alcian blue (AB) method and immunohistochemically (antibody 91.9H) to detect sulfo-Lewis(a). Based on HID/AB staining, IM was subtyped into type I (complete) or types II and III (incomplete).

RESULTS

In total, 125 sections from 38 subjects were studied. Normal squamous oesophagus, normal gastric epithelium, and type I IM were negative for sulfomucin and sulfo-Lewis(a). In type II IM, occasional goblet cells were HID and sulfo-Lewis(a) positive, but sialomucin secreting (AB positive) columnar cells were sulfo-Lewis(a) negative. Type III IM was always sulfo-Lewis(a) positive. Sulfomucin staining in dysplasia and cancer was variable, but HID positive areas were always sulfo-Lewis(a) positive.

CONCLUSIONS

Sulfo-Le(a), which is expressed on colonic mucin, is invariably present on sulfomucins in gastric IM and BO. Its presence in incomplete variants of IM and its absence from type I IM emphasises the phenotypic differences between complete and incomplete forms of metaplasia. 91.9H immunostaining is useful in IM subtyping. Characterising the molecular basis of sulfo-Lewis(a) expression may help understand the process of aberrant differentiation.

High levels of sulfated mucins in bronchoalveolar lavage fluid of ICU patients with ventilator-associated pneumonia

OBJECTIVE

To compare the levels of sulfated mucins in bronchoalveolar lavage fluid (BALF) in ICU patients with ventilator-associated pneumonia (VAP) with those in non-infectious controls, i.e., ventilated ICU patients without VAP, and nonventilated patients.

DESIGN AND SETTING

Prospective study in a mixed intensive care unit and outpatient clinic of a university hospital.

PATIENTS

The study included 56 ventilated ICU patients with VAP, 21 ventilated ICU patients without VAP, and 26 nonventilated outpatients with no pulmonary infection.

MEASUREMENTS AND RESULTS

Total cell count and differential cell count of BALF samples were determined, and sulfated mucin levels were measured. For this we used the monoclonal antibody F2 against the sulfated Lewis C structure (SO(3)-3Galbeta1-3GlcNAc). Sulfated mucin levels were significantly increased in ICU patients with VAP than in those without VAP and nonventilated patients. No statistical difference was found between the two groups of ICU patients regarding APACHE II score and the duration of mechanical ventilation prior to the bronchoalveolar lavage.

CONCLUSIONS

The increased levels of sulfated mucins in ICU patients with VAP are associated with infection and not with ventilation. The increase in sulfated mucins may favor the persistence of those micro-organisms that possess mucin sulfatase activity, which enable them to survive within the mucus, especially Pseudomonas aeruginosa.

Aquaporin-9 is expressed in a mucus-secreting goblet cell subset in the small intestine

We analyzed the expression of aquaporins (AQPs) in the small intestine to elucidate their functions, and found that AQP9, which had not previously been detected there, is present in duodenum, jejunum, and ileum. AQP9 is expressed in colon as well, but not in stomach. Also, its expression in these intestinal sections is limited to the basolateral membranes of a goblet cell subset. Our finding that AQP9 is present specifically in goblet cells as mucus-secreting cells suggests its involvement in the synthesis and/or secretion of a certain kind of mucus which may protect the intestinal surface and smooth the flow of intestinal contents.

Gastrointestinal and microbial responses to sulfate-supplemented drinking water in mice

There is increasing evidence that hydrogen sulfide (H2S), produced by intestinal sulfate-reducing bacteria (SRB), may be involved in the etiopathogenesis of chronic diseases such as ulcerative colitis and colorectal cancer. The activity of SRB, and thus H2S production, is likely determined by the availability of sulfur-containing compounds in the intestine. However, little is known about the impact of dietary or inorganic sulfate on intestinal sulfate and SRB-derived H2S concentrations. In this study, the effects of short-term (7 day) and long-term (1 year) inorganic sulfate supplementation of the drinking water on gastrointestinal (GI) sulfate and H2S concentrations (and thus activity of resident SRBs), and the density of large intestinal sulfomucin-containing goblet cells, were examined in C3H/HeJBir mice. Additionally, a PCR-denaturing gradient gel electrophoresis (DGGE)-based molecular ecology technique was used to examine the impact of sulfate-amended drinking water on microbial community structure throughout the GI tract. Average H2S concentrations ranged from 0.1 mM (stomach) to 1 mM (cecum). A sulfate reduction assay demonstrated in situ production of H2S throughout the GI tract, confirming the presence of SRB. However, H2S generation and concentrations were greatest in the cecum and colon. Sulfate supplementation of drinking water did not significantly increase intestinal sulfate or H2S concentrations, suggesting that inorganic sulfate is not an important modulator of intestinal H2S concentrations, although it altered the bacterial profiles of the stomach and distal colon of 1-year-old mice. This change in colonic bacterial profiles may reflect a corresponding increase in the density of sulfomucin-containing goblet cells in sulfate-supplemented compared with control mice.

Innate secretory immunity in response to laboratory stressors that evoke distinct patterns of cardiac autonomic activity

OBJECTIVE

Most infections begin at mucosal surfaces. These surfaces are covered by the secretory proteins of the exocrine glands (eg, the salivary, respiratory, and gastrointestinal glands), which provide a first line of innate defense. The release of these secretory proteins is under neuroendocrine control and thus, in theory, sensitive to modulation by psychosocial stress. This was empirically tested by measuring the salivary secretion of cystatin S, lactoferrin, alpha-amylase, the mucins MUC5B and MUC7, and total salivary protein in response to stressors known to evoke distinct patterns of cardiac autonomic activity.

METHODS

Thirty-two undergraduate volunteers were each subjected to two laboratory stressors and a control condition. Stressors were an active coping memory test and a passive coping video presentation showing surgical procedures. In the control condition participants viewed a didactic video presentation.

RESULTS

The stressors evoked the expected distinct patterns of cardiac autonomic activity. The memory test produced a strong increase in sympathetic activity (evidenced by a shortened preejection period), and a decrease in cardiac parasympathetic activity (evidenced by a decrease in heart rate variability). This active coping response was associated with an enhanced secretion ( microg/min, controlling for salivary flow rate) of MUC7, lactoferrin, alpha-amylase, and total salivary protein. Conversely, the surgical video produced an increase in cardiac vagal tone and a modest increase in sympathetic activity. This passive coping response was associated with an enhanced secretion of all proteins studied. These secretory responses were generally larger than the secretory responses during the active coping memory test. Correlation analyses indicated that for both stressors autonomic and cardiovascular reactivity was positively associated with an enhanced and prolonged secretory activity.

CONCLUSIONS

Stress-induced modulation of innate secretory immunity may be a contributing factor in the observed relationship between stress and susceptibility to infectious diseases. We further propose a more differentiated approach to acute stress by distinguishing among stressors with distinct autonomic nervous system effects.

Glycosidase and proteinase activity of anaerobic gram-negative bacteria isolated from women with bacterial vaginosis

BACKGROUND

It is known that glycosidases and proteases are produced by the anaerobic gram-negative bacteria associated with bacterial vaginosis (BV). We hypothesized that these enzymes enzymatically degrade mucins, thereby destroying the mucus gel that otherwise helps protect against sexually transmitted pathogens, including HIV.

GOAL

The goal was to determine glycosidase and protease production by vaginal bacteria associated with BV and to compare these with symptoms and signs of abnormal discharge and to test vaginal fluid viscosity.

STUDY DESIGN

The anaerobic gram-negative rods recovered from the vaginas of 153 women with normal flora, intermediate flora, or BV were tested for production of sialidase, fucosidase, galactosidase, glucosaminidase, and glycine and arginine aminopeptidases.

RESULTS

Women with BV had higher frequencies and concentrations of bacteria producing mucin-degrading enzymes than did women with intermediate and normal flora (P < 0.001). Women with higher concentrations of bacteria producing mucin-degrading enzymes were more likely to have a thin discharge associated with BV (P < 0.001). The viscosity of diluted vaginal fluid samples from women with BV was significantly lower than those from women with normal flora (P = 0.001).

CONCLUSION

These data support the hypothesis that BV organisms degrade the protective mucus gel.

Acidomucin goblet cell expansion induced by parenteral nutrition in the small intestine of piglets

Total parenteral nutrition (TPN) impairs small intestine development and is associated with barrier failure, inflammation, and acidomucin goblet cell expansion in neonatal piglets. We examined the relationship between intestinal goblet cell expansion and molecular and cellular indices of inflammation in neonatal piglets receiving TPN, 80% parenteral + 20% enteral nutrition (PEN), or 100% enteral nutrition (control) for 3 or 7 days. Epithelial permeability, T cell numbers, TNF-alpha and IFN-gamma mRNA expression, and epithelial proliferation and apoptosis were compared with goblet cell numbers over time. Epithelial permeability was similar to control in the TPN and PEN jejunum at day 3 but increased in the TPN jejunum by day 7. By day 3, intestinal T cell numbers were increased in TPN but not in PEN piglets. However, goblet cell expansion was established by day 3 in both the TPN and PEN ileum. Neither TNF-alpha nor IFN-gamma mRNA expression in the TPN and PEN ileum correlated with goblet cell expansion. Thus goblet cell expansion occurred independently of overt inflammation but in association with parenteral feeding. These data support the hypothesis that goblet cell expansion represents an initial defense triggered by reduced epithelial renewal to prevent intestinal barrier failure.