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Host Defenses Against Prototypical Intracellular Protozoans, the Leishmania
Published in Peter D. Walzer, Robert M. Genta, Parasitic Infections in the Compromised Host, 2020
Richard D. Pearson, Mary E. Wilson
Independently, it was observed that macrophages possess one or more receptors for marmose-terminal glycoconjugates, termed mannose/fucose receptors, that mediate the attachment and ingestion of yeast zymosan (77,78). Macromolecular ligands of these receptors inhibit attachment of L. donovani promastigotes to murine peritoneal and human macrophages (66,79-81). The use of mannan, a mannose polymer derived from yeast cell walls, or the neoglycoprotein mannose-bovine albumin, inhibited the attachment and ingestion of L. donovani promastigotes by macrophages by approximately 40-60%. The monosaccharide mannose, which is a poor inhibitor of the mannose/fucose receptor, had little effect on promastigote attachment. These data suggest that macrophage mannose/fucose receptors play an important role in parasite attachment.
Candidiasis
Published in Rebecca A. Cox, Immunology of the Fungal Diseases, 2020
Judith E. Domer, Emily W. Carrow
Many of the subcellular components of C. albicans investigated have been polysaccharides containing varying proportions of glucose and mannose, presumably in the form of glucan and mannan, in addition to small amounts of protein. Several groups,311,321,326,327 however, have turned their attention to mannan, a polymer essentially devoid of glucose, and its potential for immunomodulation. Aside from the potential interaction of mannan with phagocytic cells,326,327 mannan, as extracted by traditional techniques, appears to be heterogeneous and has within the mixture components which may be suppressive or enhancing of non-Candida antibody responses.321 Interestingly, the unfractionated mannan functions well as an antigen to detect DTH in mice immunized with viable C. albicans, and like cell-wall glycoprotein described above,320 it will suppress the development of that hypersensitivity if administered intravenously prior to sensitization.330 The components responsible for suppression or enhancement of the antibody responses to non-Candida immunogens, i.e., sheep erythrocytes and Type III pneumococcal polysaccharide, could be separated on the basis of size or charge using column chromatography.321 The mechanisms involved in the regulatory phenomena have not been elucidated.
Microbiological Diagnosis of Fungal Infections
Published in Nancy Khardori, Bench to Bedside, 2018
Gagandeep Singh, Immaculata Xess
The detection of mannan and anti-mannan antibody has been used in immunocompromised patient with hematological malignancy and those who have undergone abdominal surgery. The sensitivity and specificity is poor when used alone. However, the combined usage increases the sensitivity to 85%. More studies are required to ascertain the utility of this assay (Verduyn Lunel et al. 2009, Ellis et al. 2009).
Amphoteric Mannan as an Immune Response Modifier. New Model Immunobiologically Active Candida albicans Mannan-Based Formula
Published in Immunological Investigations, 2023
Ema Paulovičová, Lucia Paulovičová, Alžbeta Čížová, Jana Mečárová, Romana Vrzoňová, Pavol Farkaš, Slavomír Bystrický
The yeast strain Candida albicans CCY 29-3-100 (serotype A) 207/II-8 Hasenclever deposited in 1963 in the CCY Culture Collection of Yeasts, Institute of Chemistry, Center for Glycomics, Slovak Academy of Sciences, Bratislava, Slovakia, was used to isolate and purify cellular mannan from fresh biomass. Mannan was isolated as a mannan–copper complex (Jones and Stoodley 1965) from the yeast cell wall of C. albicans, serotype A. Mannan (M; 10–1000 kDa, PDI ≈ 3.3) was ultrasonically degraded (MUS; ≈ 35 kDa, PDI = 1.6) by a method described elsewhere (Čížová et al. 2015). The detailed procedure of isolation, degradation, and the characterization of mannan is given in the Supplementary data. The prepared mannan was free of proteins or chitoligomers since no nitrogen was detected by elemental analysis (Table S2, Supplementary data). The glucose content in the isolated mannan was less than 1.7 mass % as confirmed by monosaccharide composition analysis (Table S2, Supplementary data). Contamination with lipids was further excluded by FTIR and NMR spectroscopies confirming the structure and purity of the isolated mannans (Fig. S1 and S2, Supplementary data).
High iron-mediated increased oral fungal burden, oral-to-gut transmission, and changes to pathogenicity of Candida albicans in oropharyngeal candidiasis
Published in Journal of Oral Microbiology, 2022
Aparna Tripathi, Anubhav Nahar, Rishabh Sharma, Trevor Kanaskie, Nezar Al-Hebshi, Sumant Puri
The non-uniform effect of iron on the cell wall of oral isolates of C. albicans can have multiple potential causes. As the outermost layer, mannans face direct exposure of environmental stresses and are greatly influenced by various kinds of oral challenges, such as diverse bacterial microbiota and dietary supplements in the host [36]. Such challenges can cause intrinsic variations in the mannan levels in the cell wall of clinical isolates, prior to those being exposed to high and low iron in vitro (Figure 3(a)), thereby causing a variable effect of iron on the mannan content in these isolates. Further, changes in the cell wall mannan can affect the activity of the cell wall associated proteins that participate in cell wall morphogenesis, such as chitinases (hydrolyses chitin), β‐1,3-glucanases (hydrolyses β‐1,3-glucan), and cell wall remodeling enzymes (e.g. β‐1,3-glucan transferase BGL2) [37]. These in turn can explain the inter-strain variation in chitin and β‐1,3-glucan levels among the oral isolates (Figure 3(b,c)).
Dietary manipulation of the gut microbiome in inflammatory bowel disease patients: Pilot study
Published in Gut Microbes, 2022
Barbara Olendzki, Vanni Bucci, Caitlin Cawley, Rene Maserati, Margaret McManus, Effie Olednzki, Camilla Madziar, David Chiang, Doyle V. Ward, Randall Pellish, Christine Foley, Shakti Bhattarai, Beth A. McCormick, Ana Maldonado-Contreras
We next evaluated the functional capacity of the microbiome during the intervention. At baseline, we found that the metagenomic capacity varied greatly by participant, with most samples clustering by participant (data not shown). However, we observe that during the intervention the microbiome exhibited an increased genetic capacity for 1) biosynthesis of several key amino acids (i.e., histidine, lysine, threonine, methionine, serine, glycine, isoleucine, and arginine); 2) degradation of mannan (a dietary fiber); and 3) β-oxidation for fatty acid degradation (Figure 4). Roseburia sp. and Faecalibacterium sp. – both favored during the IBD-AID intervention are main degraders of dietary mannan ultimately producing SCFA.52,53 Mannans are found in the endospermic tissue of nuts (homopolymeric mannan), barley, oats (β-glucans or mannoproteins), coffee beans, coconut palm, tomato, and legume seeds (galactomannan).54 Similarly, increased microbiome gene capacity for oxidation of fatty acids during the intervention also suggests increased availability of SCFAs. Thus, we further investigated the impact of IBD-AID on the pool of microbial genes involved in SCFA production during the intervention.