An adjuvant strategy enabled by modulation of the physical properties of microbial ligands expands antigen immunogenicity.

Activation of the innate immune system via pattern recognition receptors (PRRs) is key to generate lasting adaptive immunity. PRRs detect unique chemical patterns associated with invading microorganisms, but whether and how the physical properties of PRR ligands influence the development of the immune response remains unknown. Through the study of fungal mannans, we show that the physical form of PRR ligands dictates the immune response. Soluble mannans are immunosilent in the periphery but elicit a potent pro-inflammatory response in the draining lymph node (dLN). By modulating the physical form of mannans, we developed a formulation that targets both the periphery and the dLN. When combined with viral glycoprotein antigens, this mannan formulation broadens epitope recognition, elicits potent antigen-specific neutralizing antibodies, and confers protection against viral infections of the lung. Thus, the physical properties of microbial ligands determine the outcome of the immune response and can be harnessed for vaccine development.

The structure of a C. neoformans polysaccharide motif recognized by protective antibodies: A combined NMR and MD study.

Cryptococcus neoformans is a fungal pathogen responsible for cryptococcosis and cryptococcal meningitis. The C. neoformans' capsular polysaccharide and its shed exopolysaccharide function both as key virulence factors and to protect the fungal cell from phagocytosis. Currently, a glycoconjugate of these polysaccharides is being explored as a vaccine to protect against C. neoformans infection. In this study, NOE and J-coupling values from NMR experiments were consistent with a converged structure of the synthetic decasaccharide, GXM10-Ac3, calculated from MD simulations. GXM10-Ac3 was designed as an extension of glucuronoxylomannan (GXM) polysaccharide motif (M2) which is common in the clinically predominant serotype A strains and is recognized by protective forms of GXM-specific monoclonal antibodies. The M2 motif is a hexasaccharide with a three-residue α-mannan backbone, modified by ß-(1→2)-xyloses (Xyl) on the first two mannoses (Man) and a ß-(1→2)-glucuronic acid (GlcA) on the third Man. Combined NMR and MD analyses reveal that GXM10-Ac3 adopts an extended structure, with Xyl/GlcA branches alternating sides along the α-mannan backbone. O-acetyl esters also alternate sides and are grouped in pairs. MD analysis of a twelve M2-repeating unit polymer supports the notion that the GXM10-Ac3 structure is uniformly represented throughout the polysaccharide. This derived GXM model displays high flexibility while maintaining a structural identity, yielding insights to further explore intermolecular interactions between polysaccharides, interactions with anti-GXM mAbs, and the cryptococcal polysaccharide architecture.

Acetylation of homogalacturonan and rhamnogalacturonan-I is catalyzed by a suite of trichome birefringence-like proteins.

Plant cell wall polysaccharides, including xylan, mannan, xyloglucan, and pectins, are often acetylated and members of the domain of unknown function 231 (DUF231)/trichome birefringence-like (TBL) family have been shown to be O-acetyltransferases mediating the acetylation of xylan, mannan, and xyloglucan. However, little is known about the O-acetyltransferases responsible for pectin acetylation. In this report, we biochemically characterized a suite of Arabidopsis DUF231/TBL proteins for their roles in pectin acetylation. We generated 24 TBL recombinant proteins in mammalian cells and demonstrated that 10 of them were able to transfer acetyl groups from acetyl-CoA onto the pectins homogalacturonan (HG) or rhamnogalacturonan-I (RG-I), and thus were named pectin O-acetyltransferase 1 to 10 (POAT1 to 10). It was found that POAT2,4,9,10 specifically acetylated HG and POAT5,6 acetylated RG-I, whereas POAT1,3,7,8 could act on both HG and RG-I. The acetylation of HG and RG-I by POATs was further corroborated by hydrolysis with pectin acetylesterases and by nuclear magnetic resonance spectroscopy. In addition, mutations of the conserved GDS and DXXH motifs in POAT3 and POAT8 were shown to lead to a loss of their ability to acetylate HG and RG-I. Furthermore, simultaneous RNA interference downregulation of POAT1,3,6,7,8 resulted in reduced cell expansion, impaired plant growth, and decreased pectin acetylation. Together, our findings indicate that these POATs are pectin O-acetyltransferases involved in acetylation of the pectin polysaccharides HG and RG-I.

The galactose metabolism genes UGE1 and UGM1 are novel virulence factors of the maize anthracnose fungus Colletotrichum graminicola.

Fungal cell walls represent the frontline contact with the host and play a prime role in pathogenesis. While the roles of the cell wall polymers like chitin and branched ß-glucan are well understood in vegetative and pathogenic development, that of the most prominent galactose-containing polymers galactosaminogalactan and fungal-type galactomannan is unknown in plant pathogenic fungi. Mining the genome of the maize pathogen Colletotrichum graminicola identified the single-copy key galactose metabolism genes UGE1 and UGM1, encoding a UDP-glucose-4-epimerase and UDP-galactopyranose mutase, respectively. UGE1 is thought to be required for biosynthesis of both polymers, whereas UGM1 is specifically required for fungal-type galactomannan formation. Promoter:eGFP fusion strains revealed that both genes are expressed in vegetative and in pathogenic hyphae at all stages of pathogenesis. Targeted deletion of UGE1 and UGM1, and fluorescence-labeling of galactosaminogalactan and fungal-type galactomannan confirmed that Δuge1 mutants were unable to synthesize either of these polymers, and Δugm1 mutants did not exhibit fungal-type galactomannan. Appressoria of Δuge1, but not of Δugm1 mutants, were defective in adhesion, highlighting a function of galactosaminogalactan in the establishment of these infection cells on hydrophobic surfaces. Both Δuge1 and Δugm1 mutants showed cell wall defects in older vegetative hyphae and severely reduced appressorial penetration competence. On intact leaves of Zea mays, both mutants showed strongly reduced disease symptom severity, indicating that UGE1 and UGM1 represent novel virulence factors of C. graminicola.

Galactomannan utilization by Cellvibrio japonicus relies on a single essential α-galactosidase encoded by the aga27A gene.

Plant mannans are a component of lignocellulose that can have diverse compositions in terms of its backbone and side-chain substitutions. Consequently, the degradation of mannan substrates requires a cadre of enzymes for complete reduction to substituent monosaccharides that can include mannose, galactose, and/or glucose. One bacterium that possesses this suite of enzymes is the Gram-negative saprophyte Cellvibrio japonicus, which has 10 predicted mannanases from the Glycoside Hydrolase (GH) families 5, 26, and 27. Here we describe a systems biology approach to identify and characterize the essential mannan-degrading components in this bacterium. The transcriptomic analysis uncovered significant changes in gene expression for most mannanases, as well as many genes that encode carbohydrate active enzymes (CAZymes) when mannan was actively being degraded. A comprehensive mutational analysis characterized 54 CAZyme-encoding genes in the context of mannan utilization. Growth analysis of the mutant strains found that the man26C, aga27A, and man5D genes, which encode a mannobiohydrolase, α-galactosidase, and mannosidase, respectively, were important for the deconstruction of galactomannan, with Aga27A being essential. Our updated model of mannan degradation in C. japonicus proposes that the removal of galactose sidechains from substituted mannans constitutes a crucial step for the complete degradation of this hemicellulose.

An essential role for mannan degradation in both cell growth and secondary cell wall formation.

Coordination of secondary cell wall deposition and cell expansion during plant growth is required for cell development, particularly in vascular tissues. Yet the fundamental coordination process has received little attention. We observed that the Arabidopsis endo-1,4-mannanase gene, AtMAN6, is involved in the formation of cell walls in vascular tissues. In the inflorescence stem, the man6 mutant had smaller vessel cells with thicker secondary cell walls and shorter fiber cells. Elongation growth was reduced in the root, and secondary cell wall deposition in vessel cells occurred early. Overexpression of AtMAN6 resulted in the inverse phenotypes of the man6 mutant. AtMAN6 was discovered on the plasma membrane and was specifically expressed in vessel cells during its early development. The AtMAN6 protein degraded galactoglucomannan to produce oligosaccharides, which caused secondary cell wall deposition in vessel and fiber cells to be suppressed. Transcriptome analysis revealed that the expression of genes involved in the regulation of secondary cell wall synthesis was changed in both man6 mutant and AtMAN6 overexpression plants. AtMAN6's C-terminal cysteine repeat motif (CCRM) was found to facilitate homodimerization and is required for its activity. According to the findings, the oligosaccharides produced by AtMAN6 hydrolysis may act as a signal to mediate this coordination between cell growth and secondary cell wall deposition.

A randomized, double-blind, placebo-controlled trial with mannan-conjugated birch pollen allergoids.

BACKGROUND: There is still great need to develop new strategies to improve the efficacy of allergen immunotherapies with optimal safety standards for patients. A new promising approach is to couple allergoids to mannan. The objective of this phase IIa/IIb study was to identify the optimal dose of mannan-conjugated birch pollen allergoids for the short-course treatment of birch pollen-induced allergic rhinoconjunctivitis. METHODS: For this prospective, randomized, double-blind, placebo-controlled, dose-finding study, 246 birch pollen-allergic adults received 0.5 mL placebo or 1000, 3000 or 10,000 mTU/mL of mannan-conjugated birch pollen allergoids at five pre-seasonal visits. Efficacy was assessed by comparing allergic rhinoconjunctivitis symptoms and use of anti-allergic medication during the peak of the birch pollen season 2020. Immunologic, tolerability and safety effects were also analysed. RESULTS: The highest dose of mannan-conjugated birch pollen allergoids reduced the combined symptom and medication score during the peak birch pollen season by a median of 24.7% compared to placebo. The production of Bet v 1 specific IgG4 significantly increased in a dose-dependent manner (3.6- and 4.5-fold) in the 3000 and 10,000 mTU/mL groups. The Bet v 1 specific IgE/IgG4 ratio was also strongly reduced (up to -70%). No fatalities nor serious adverse events were reported, and no adrenaline was used. In total, four systemic reactions occurred (two grade I and two grade II). CONCLUSION: All doses of mannan-conjugated birch pollen allergoids can be considered as safe. Since the application of 10,000 mTU/mL resulted in the highest efficacy, this dose qualifies for further investigation.

Purified Free Mannan Promotes Tolerogenic Responses in Peanut-Stimulated Human Dendritic Cells.

INTRODUCTION: IgE-mediated peanut allergy is an important public health problem of increasing prevalence leading to anaphylactic reactions both in children and adults. Allergen-specific oral immunotherapy (OIT) is the single treatment with the potential capacity to modify the course of the disease, but it still faces some drawbacks in terms of efficacy, safety, patients' adherence, and cost. Alternative strategies, including the use of novel adjuvants, to overcome such limitations are highly demanded. The main aim of this study was to search for potential novel adjuvants for peanut OIT by assessing the capacity of free purified mannan and different toll-like receptor ligands (TLR-Ls) to immunomodulate the responses of human monocyte-derived dendritic cells (hmoDCs) to peanut allergens. METHODS: Monocytes were isolated from PBMCs of healthy donors and differentiated into hmoDCs. Flow cytometry, ELISA, coculture, and suppression assay were performed to assess the effects of TLR-Ls, mannan, and crude peanut extract (CPE) in hmoDCs. RESULTS: Purified free mannan increased the expression levels of HLA-DR, CD86, CD83, and PD-L1 and induced a higher IL-10/IL-6 cytokine ratio in hmoDCs compared to the stimulation with different TLR-Ls. Mannan significantly increased the expression of HLA-DR, the maturation marker CD83, the tolerogenic marker PD-L1, as well as the production of IL-10, IL-6, and TNF-α in CPE-stimulated hmoDCs. Supporting these tolerogenic properties, mannan also significantly increased the frequency of FOXP3+ regulatory T cells generated by CPE-treated hmoDCs with functional suppressive capacity. CONCLUSIONS: We uncover that purified free mannan induces tolerogenic responses in human DCs stimulated with peanut allergens, suggesting mannan as a suitable potential novel adjuvant to be exploited in the context of OIT for peanut allergy.

Time-resolved fluoroimmunoassay for Aspergillus detection based on anti-galactomannan monoclonal antibody from stable cell line.

Invasive Aspergillosis is a high-risk illness with a high death rate in immunocompromised people due to a lack of early detection and timely treatment. Based on immunology study, we achieved an efficient production of anti-galactomannan antibody by Chinese hamster ovary (CHO) cells and applied it to time-resolved fluoroimmunoassay for Aspergillus galactomannan detection. We first introduced dual promoter expression vector into CHO host cells, and then applied a two-step screening strategy to screen the stable cell line by methionine sulfoximine pressurization. After amplification and fermentation, antibody yield reached 4500 mg/L. Then we conjugated the antibodies with fluorescent microspheres to establish a double antibody sandwich time-resolved fluoroimmunoassay, which was compared with the commercial Platelia™ Aspergillus Ag by clinical serum samples. The preformed assay could obtain the results in less than 25 min, with a limit of detection for galactomannan of approximately 1 ng/mL. Clinical results of the two methods showed that the overall percent agreement was 97.7% (95% CI: 96.6%-98.4%) and Cohen's kappa coefficient was 0.94. Overall, the assay is highly consistent with commercial detection, providing a more sensitive and effective method for the rapid diagnosis of invasive aspergillosis.

Design of Stretchable and Conductive Self-Adhesive Hydrogels as Flexible Sensors by Guar-Gum-Enabled Dynamic Interactions.

The limited elasticity and inadequate bonding of hydrogels made from guar gum (GG) significantly hinder their widespread implementation in personalized wearable flexible electronics. In this study, we devise GG-based self-adhesive hydrogels by creating an interpenetrating network of GG cross-linked with acrylic, 4-vinylphenylboronic acid, and Ca2+. With the leverage of the dynamic interactions (hydrogen bonds, borate ester bonds, and coordination bonds) between -OH in GG and monomers, the hydrogel exhibits a high stretchability of 700%, superior mechanical stress of 110 kPa, and robust adherence to several substrates. The adhesion strength of 54 kPa on porcine skin is obtained. Furthermore, the self-adhesive hydrogel possesses stable conductivity, an elevated gauge factor (GF), and commendable durability. It can be affixed to the human body as a strain sensor to obtain precise monitoring of human movement behavior. Our research offers possibilities for the development of GG-based hydrogels and applications in wearable electronics and medical monitoring.

Self-Healing Guar Gum-Based Nanocomposite Hydrogel Promotes Infected Wound Healing through Photothermal Antibacterial Therapy.

Preventing bacterial infections is a crucial aspect of wound healing. There is an urgent need for multifunctional biomaterials without antibiotics to promote wound healing. In this study, we fabricated a guar gum (GG)-based nanocomposite hydrogel, termed GBTF, which exhibited photothermal antibacterial therapy for infected wound healing. The GBTF hydrogel formed a cross-linked network through dynamic borate/diol interactions between GG and borax, thereby exhibiting simultaneously self-healing, adaptable, and injectable properties. Additionally, tannic acid (TA)/Fe3+ nanocomplexes (NCs) were incorporated into the hydrogel to confer photothermal antibacterial properties. Under the irradiation of an 808 nm near-infrared laser, the TA/Fe3+ NCs in the hydrogel could rapidly generate heat, leading to the disruption of bacterial cell membranes and subsequent bacterial eradication. Furthermore, the hydrogels exhibited good cytocompatibility and hemocompatibility, making them a precandidate for preclinical and clinical applications. Finally, they could significantly promote bacteria-infected wound healing by reducing bacterial viability, accelerating collagen deposition, and promoting epithelial remodeling. Therefore, the multifunctional GBTF hydrogel, which was composed entirely of natural substances including guar gum, borax, and polyphenol/ferric ion NCs, showed great potential for regenerating infected skin wounds in clinical applications.

Ag Nanoparticle Incorporated Guar Gum-Sodium Alginate-I-Carrageenan Tribiopolymer Blended Cloth Waste Lint Extracted Cellulose Nanocrystal Antimicrobial Composite Film.

A biopolymer-based formulation for robust and active food packaging material was developed. This material consisted of a blend of three biopolymers (guar gum-sodium alginate-i-carrageenan) reinforced by cellulose nanocrystals (CNC) alongside the integration of silver nanoparticles (AgNPs) with varying sizes. The CNC utilized in this process was derived from cloth waste lint (CWL) generated from a household cloth dryer machine. This CNC synthesis underwent a series of solvent treatments to yield the CNC used in the composite. CNC and AgNPs were incorporated into the tribiopolymeric blend matrix to construct a nanocomposite film that showed excellent tensile strength (∼90 MPa). The nanocomposite film also exhibited antimicrobial activity against Escherichia coli ATCC 25922 and Bacillus cereus MTCC 1272. In this report, it was demonstrated that the zone of inhibition against E. coli and B. cereus depends on the variation of size and amount of AgNPs inside the polymeric matrix. The practical applicability of such a film was also demonstrated by applying it to sliced bread and the enhancement of the shelf life of the raped bread was compared with a control. Thus, the guar gum-sodium alginate-i-carrageenan tribiopolymer blend with a cloth waste lint extracted cellulose nanocrystal composite film is antimicrobial, hence, an excellent candidate as an active packaging film.

Evaluation of the JF5-based Aspergillus galactomannoprotein lateral flow device for diagnosing invasive aspergillosis in cancer patients.

PURPOSE: Cancer patients are at heightened risk for invasive aspergillosis (IA), a condition associated with elevated mortality risk. The JF5-based Aspergillus Galactomannoprotein Lateral Flow Device (AspLFD) offers rapid point-of-care testing (POCT) for IA. This study evaluated the diagnostic performance of AspLFD in cancer populations. METHODS: This retrospective study examined cancer patient bronchoalveolar lavage fluid (BALF) and serum samples collected between September 2021 and January 2023. Both AspLFD and galactomannan (GM) assays were conducted, and the results were analysed by two independent researchers. RESULTS: This study included 242 samples from 218 cancer patients, with 58 BALF and 184 serum samples. The overall agreement between AspLFD and GM assay results was 92.1%, with a kappa value of 0.552. AspLFD diagnosed proven/probable IA with a sensitivity and specificity of 91.7% and 95.3%, respectively, whereas GM exhibited sensitivity and specificity values of 83.3% and 93.7%, respectively. There were no statistical differences in the sensitivity and specificity between the two methods (P > 0.05). For serum analyses, AspLFD and GM exhibited similar sensitivity (66.7% vs. 66.7%, P > 0.05) and specificity (98.6% vs. 96.6%, P > 0.05) values. However, the sensitivity of the AspLFD was superior to the GM assay (100% vs. 88.9%) in BALF analyses but the difference was not statistically significant (P > 0.05), with no difference in specificity (83.7% vs. 83.7%, P > 0.05). In the solid-tumour cohort, both the AspLFD and GM assay exhibited high sensitivity (100% for both) and specificity (94.2% vs. 92.8%, P > 0.05). CONCLUSION: The AspLFD demonstrated good performance in diagnosing IA in cancer patients, especially those with solid tumours. The AspLFD is thus an alternative POCT, particularly when GM evaluations are not readily available.

Performance of the Aspergillus galactomannan lateral flow assay with a digital reader for the diagnosis of invasive aspergillosis: a multicenter study.

PURPOSE: The objective of this multicenter study was to compare the diagnostic performance of lateral flow assay (LFA) and enzyme-linked immunosorbent assay (ELISA) to detect the Dynamiker Aspergillus Galactomannan levels in serum and bronchoalveolar lavage fluid (BALF) samples for I. METHODS: We registered 310 clinically suspected Aspergillus infection patients from December 2021 to February 2023 and classified them into subgroups as the "IA group" and "non-IA group" based on the latest EORTC/MSG guidelines. The immunoassays were analyzed by LFA and ELISA respectively. RESULTS: Galactomannan was examined using LFA, and serum and BALF samples demonstrated sensitivities of 82.57% and 89.47%, specificities of 90.76% and 92.00%, PPVs of 89.11% and 96.23%, and NPVs of 85.04% and 79.31%, respectively. Galactomannan was observed using two assays in serum and BALF samples and showed PPAs of 95.11% and 93.33%, NPAs of 89.19% and 96.30%, and TPAs of 92.47% and 94.25%, respectively. The ROC curve demonstrated that LFA had optimum diagnostic value when the index value (I value) = 0.5, the sensitivity was 84.94%, and the specificity was 90.97%. CONCLUSION: Compared to the ELISA method, the LFA has shown excellent performance for the diagnosis of IA in serum and BALF sample and can be used as an assay for the early diagnosis of patients with IA. The dynamic change in galactomannan levels may be useful for assessing treatment response.

Impact of posaconazole prophylaxis and antifungal treatment on BAL GM performance in hematology malignancy patients with febrile neutropenia: a real life experience.

BACKGROUND: Diagnostic accuracy of galactomannan measurements is highly variable depending on the study population, diagnostic procedures, and treatment procedures. We aimed to evaluate the effect of posaconazole prophylaxis and empiric antifungal treatment upon diagnostic accuracy of GM measurements in bronchoalveolar lavage (BAL), bronchial lavage (BL), and serum in hematological malignancy population. METHODS: Patients hospitalized in a single tertiary care center with hematologic malignancies undergoing fiberoptic bronchoscopy (FOB) with a preliminary diagnosis of IPA were retrospectively included. RESULTS: In all the study population (n = 327), AUC for BAL, BL, and serum GM were as follows: 0.731 [0.666-0.790], 0.869 [0.816-0.912], and 0.610 [0.540-0.676] with BL samples having the best diagnostic value. GM measurements in patients under posaconazole prophylaxis (n = 114) showed similar diagnostic performance. While specificity was similar between patients with and without posaconazole prophylaxis, sensitivity of GM measurements was lower in patients with prophylaxis. Analyses with patient classified according to antifungal treatment at the time of FOB procedure (n = 166) showed a decreased diagnostic accuracy in serum GM and BAL GM measurements related with the duration of treatment. However, BAL, BL, and serum GM measurements presented similar sensitivity and specificity in higher cut-off values in longer durations of antifungal treatment. CONCLUSION: Our study shows that posaconazole prophylaxis and active short-term (3 days) antifungal treatment do not significantly affect overall diagnostic performance of GM measurements in bronchoalveolar lavage and bronchial lavage samples. However, using different cut-off values for patients receiving active treatment might be suggested to increase sensitivity.

Evaluation of the mannan antigen assay in neonates with or without Candida albicans colonization.

Mannan antigen (MA) in neonates as a marker of invasive candidemia is not well studied, although 4% of all neonatal intensive care unit admissions are attributed to Candida spp. infections. The aim of this case-control study was to evaluate the performance of MA (Platelia™ Candida AgPluskit, Bio-Rad) in neonates who had rectal Candida colonization or in non-colonized controls. We cultured 340 rectal swabs of neonates and MA was negative in 24/25 C. albicans colonized (96% specificity) and in 30/30 non-colonized neonates (100% specificity). The results indicate a high specificity of the assay, which could be useful in neonates with possible candidemia.

The present study aimed to evaluate the use of mannan antigen (MA) assay in a neonatal unit and compared between C. albicans colonized and non-colonized infants. According to our results, MA found to have high specificity in both groups.

Physical impediment to sodium houttuyfonate conversely reinforces ß-glucan exposure stimulated innate immune response to Candida albicans.

Candida albicans is a dimorphic opportunistic pathogen in immunocompromised individuals. We have previously demonstrated that sodium houttuyfonate (SH), a derivative of medicinal herb Houttuynia cordata Thunb, was effective for antifungal purposes. However, the physical impediment of SH by C. albicans ß-glucan may weaken the antifungal activity of SH. In this study, the interactions of SH with cell wall (CW), extracellular matrix (EM), CW ß-glucan, and a commercial ß-glucan zymosan A (ZY) were inspected by XTT assay and total plate count in a standard reference C. albicans SC5314 as well as two clinical fluconazole-resistant strains Z4935 and Z5172. After treatment with SH, the content and exposure of CW ß-glucan, chitin, and mannan were detected, the fungal clearance by phagocytosis of RAW264.7 and THP-1 was examined, and the gene expressions and levels of cytokines TNF-ɑ and IL-10 were also monitored. The results showed that SH could be physically impeded by ß-glucan in CW, EM, and ZY. This impediment subsequently triggered the exposure of CW ß-glucan and chitin with mannan masked in a time-dependent manner. SH-induced ß-glucan exposure could significantly enhance the phagocytosis and inhibit the growth of C. albicans. Meanwhile, the SH-pretreated fungal cells could greatly stimulate the cytokine gene expressions and levels of TNF-ɑ and IL-10 in the macrophages. In sum, the strategy that the instant physical impediment of C. albicans CW to SH, which can induce the exposure of CW ß-glucan may be universal for C. albicans in response to physical deterrent by antifungal drugs.

The potential mechanism of concentrated mannan-oligosaccharide promoting goldfish's (Carassius auratus Linnaeus) resistance to Ichthyophthirius multifiliis invasion.

Because of the low host specificity, Ichthyophthirius multifiliis (Ich) can widely cause white spot disease in aquatic animals, which is extremely difficult to treat. Prior research has demonstrated a considerable impact of concentrated mannan-oligosaccharide (cMOS) on the prevention of white spot disease in goldfish, but the specific mechanism is still unknown. In this study, transcriptome sequencing, histological analysis, immunofluorescence analysis, phagocytosis activity assay and qRT-PCR assay were used to systematically reveal the potential mechanism of cMOS in supporting the resistance of goldfish (Carrasius auratus) to Ich invasion. According to the transcriptome analysis, the gill tissue of goldfish receiving the cMOS diet showed greater expression of mannose-receptor (MRC) related genes, higher phagocytosis activity, up-regulated expression of phagocytosis-related genes and inflammatory-related genes compared with the control, indicating that cMOS can have an effect on phagocytosis and non-specific immunity of goldfish. After the Ich challenge, transcriptome analysis revealed that cMOS fed goldfish displayed a higher level of phagocytic response, whereas non-cMOS fed goldfish displayed a greater inflammatory reaction. Besides, after Ich infection, cMOS-fed goldfish displayed greater phagocytosis activity, a stronger MRC positive signal, higher expression of genes associated with phagocytosis (ABCB2, C3, MRC), and lower expression of genes associated with inflammation (IL-1ß, IL-17, IL-8, TNF-α, NFKB). In conclusion, our experimental results suggest that cMOS may support phagocytosis by binding to MRC on the macrophage cell membrane and change the non-specific immunity of goldfish by stimulating cytokine expression. The results of this study provide new insights for the mechanism of cMOS on parasitic infection, and also suggest phagocytosis-related pathways may be potential targets for prevention of Ich infection.

Synthesis of galactomannan fragments to help NMR assignment of polysaccharides extracted from lichens.

The synthesis of six model trisaccharides representative of galactomannans produced by lichens was performed through stereoselective glycosylation. These standards include linear and branched galactomannans bearing either galactofuranosyl or galactopyranosyl entities. The complete assignment of 1H and 13C signals for both forms of synthetically reduced oligosaccharides was performed. The resulting NMR data were used to quickly demonstrate the structural characteristics of minor polysaccharides within different extracts of three representative lichens.

Vaginal prevention of Candida albicans: synergistic effect of lactobacilli and mannan oligosaccharides (MOS).

Vulvovaginal candidiasis (VVC) affects approximately 30-50% of women at least once during their lifetime, causing uncomfortable symptoms and limitations in their daily quality of life. Antifungal therapy is not very effective, does not prevent recurrencies and usually causes side effects. Therefore, alternative therapies are urgently needed. The goal of this work was to investigate the potential benefits of using mannan oligosaccharides (MOS) extracts together with a Lactobacillus sp. pool, composed by the most significant species present in the vaginal environment, to prevent infections by Candida albicans. Microbial growth of isolated strains of the main vaginal lactobacilli and Candida strains was assessed in the presence of MOS, to screen their impact upon growth. A pool of the lactobacilli was then tested against C. albicans in competition and prophylaxis studies; bacterial and yeast cell numbers were quantified in specific time points, and the above-mentioned studies were assessed in simulated vaginal fluid (SVF). Finally, adhesion to vaginal epithelial cells (HeLa) was also evaluated, once again resorting to simultaneous exposure (competition) or prophylaxis assays, aiming to measure the effect of MOS presence in pathogen adherence. Results demonstrated that MOS extracts have potential to prevent vaginal candidiasis in synergy with vaginal lactobacilli, with improved results than those obtained when using lactobacilli alone. KEY POINTS: Potential benefits of MOS extracts with vaginal lactobacilli to prevent C. albicans infections. MOS impacts on growth of vaginal lactobacilli pool and C. albicans in SVF. MOS extracts in synergy with L. crispatus inhibit C. albicans adhesion in HeLa cells.