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Clinical Microbiology and Infection :... Sep 2021Diagnosing invasive or chronic fungal infections is a challenge, particularly in the immunocompromised host. Microscopy and culture remain the reference standard, but... (Review)
Review
BACKGROUND
Diagnosing invasive or chronic fungal infections is a challenge, particularly in the immunocompromised host. Microscopy and culture remain the reference standard, but are insensitive. The use of non-culture-based techniques is recommended in conjunction with conventional methods to improve the diagnostic yield.
OBJECTIVES
The aim was to provide an updated 2021 inventory of fungal antigen and serology tests for diagnosing invasive and chronic fungal infections, the key focus was set on Aspergillus, Candida and Cryptococcus species.
SOURCES
Pubmed search for publications with the key words fungal antigen tests, laboratory-based diagnosis of invasive pulmonary aspergillosis, chronic pulmonary aspergillosis, invasive candidiasis, invasive fungal infections and cryptococcal infections published from 2017 to 2020.
CONTENT
Antigen assays such as the galactomannan (GM) and β-d-glucan detection systems are frequently used, but these tests vary in sensitivity and specificity, depending on the patient population involved, specimens inspected, cut-offs defined, test strategy applied and inclusion or exclusion of possible fungal case definitions. Multiple different detection systems are available, with recently introduced new point-of-care tests such as the lateral flow device and the lateral flow assay. Despite a wide heterogeneity in populations evaluated, studies indicate a better diagnostic performance of bronchoalveolar lavage GM in comparison with serum GM, and a suboptimal specificity of GM bronchoalveolar lavages (cut-off ≥1) and serum β-d-glucan in non-neutropenic individuals. Point-of-care cryptococcal antigen tests show excellent performance.
IMPLICATIONS
There are fungal antigen detection tests available with excellent to reasonable clinical performance to diagnose invasive fungal infections. Only a few assays are useful to monitor therapeutic response. There are multiple marketed IgG antibody tests to detect Aspergillus fumigatus antibodies, the titres vary widely and the performance differs significantly. In general, diagnostic tests are vulnerable to being affected by the host, the microbe and laboratory setting.
Topics: Antigens, Fungal; Bronchoalveolar Lavage Fluid; Candidiasis, Invasive; Clinical Laboratory Techniques; Cryptococcosis; Glucans; Humans; Invasive Fungal Infections; Invasive Pulmonary Aspergillosis; Mannans; Sensitivity and Specificity
PubMed: 33601011
DOI: 10.1016/j.cmi.2021.02.005 -
Molecules (Basel, Switzerland) Apr 2019is a medicinal plant species of the genus Aloe with a long history of usage around the world. Acemannan, considered one of the main bioactive polysaccharides of ,... (Review)
Review
is a medicinal plant species of the genus Aloe with a long history of usage around the world. Acemannan, considered one of the main bioactive polysaccharides of , possesses immunoregulation, anti-cancer, anti-oxidation, wound healing and bone proliferation promotion, neuroprotection, and intestinal health promotion activities, among others. In this review, recent advancements in the extraction, purification, structural characteristics and biological activities of acemannan from were summarized. Among these advancements, the structural characteristics of purified polysaccharides were reviewed in detail. Meanwhile, the biological activities of acemannan from determined by , and clinical experiments are summarized, and possible mechanisms of these bioactivities were discussed. Moreover, the latest research progress on the use of acemannan in dentistry and wound healing was also summarized in details. The structure-activity relationships of acemannan and its medical applications were discussed. Finally, new perspectives for future research work on acemannan were proposed. In conclusion, this review summarizes the extraction, purification, structural characteristics, biological activities and pharmacological applications of acemannan and provides information for the industrial production and possible applications in dentistry and wound healing in the future.
Topics: Aloe; Animals; Humans; Mannans; Plants, Medicinal; Polysaccharides; Structure-Activity Relationship; Wound Healing
PubMed: 31010204
DOI: 10.3390/molecules24081554 -
International Journal of Molecular... Jun 2019In recent decades, various polysaccharides isolated from algae, mushrooms, yeast, and higher plants have attracted serious attention in the area of nutrition and... (Review)
Review
In recent decades, various polysaccharides isolated from algae, mushrooms, yeast, and higher plants have attracted serious attention in the area of nutrition and medicine. The reasons include their low toxicity, rare negative side effects, relatively low price, and broad spectrum of therapeutic actions. The two most and best-studied polysaccharides are mannan and glucan. This review focused on their biological properties.
Topics: Animals; Antineoplastic Agents; Fungal Polysaccharides; Glucans; Humans; Hypolipidemic Agents; Immunologic Factors; Macrophages; Mannans
PubMed: 31261851
DOI: 10.3390/ijms20133189 -
The New Phytologist May 2022Hemicellulosic polysaccharides built of β-1,4-linked mannose units have been found throughout the plant kingdom and have numerous industrial applications. Here, I... (Review)
Review
Hemicellulosic polysaccharides built of β-1,4-linked mannose units have been found throughout the plant kingdom and have numerous industrial applications. Here, I review recent advances in the biosynthesis and modification of plant β-mannans. These matrix polymers can associate with cellulose bundles to impact the mechanical properties of plant fibers or biocomposites. In certain algae, mannan microfibrils even replace cellulose as the dominant structural component of the cell wall. Conversely, patterned galactoglucomannan found in Arabidopsis thaliana seed mucilage significantly modulates cell wall architecture and abiotic stress tolerance despite its relatively low content. I also discuss the subcellular requirements for β-mannan biosynthesis, the increasing number of carbohydrate-active enzymes involved in this process, and the players that continue to be puzzling. I discuss how cellulose synthase-like enzymes elongate (gluco)mannans in orthogonal hosts and highlight the discoveries of plant enzymes that add specific galactosyl or acetyl decorations. Hydrolytic enzymes such as endo-β-1,4-mannanases have recently been involved in a wide range of biological contexts including seed germination, wood formation, heavy metal tolerance, and defense responses. Synthetic biology tools now provide faster tracks to modulate the increasingly-relevant mannan structures for improved plant traits and bioproducts.
Topics: Arabidopsis; Cell Wall; Cellulose; Mannans; Plants; Polysaccharides
PubMed: 35285041
DOI: 10.1111/nph.18091 -
Journal of Nutritional Science 2020Apart from its role as a digestive and absorptive organ, the gastrointestinal (GI) tract is a vital immune organ that encompasses roughly 70 % of the total immune cells... (Review)
Review
Apart from its role as a digestive and absorptive organ, the gastrointestinal (GI) tract is a vital immune organ that encompasses roughly 70 % of the total immune cells of the body. As such, the physical, chemical and nutrient composition of the diet influences overall GI function, effectively as an immune organ. With the improvement in feed technology, agro-industrial co-products that are high in fibre have been widely used as a feed ingredient in the diets of pigs and poultry. Arabinoxylan (AX) and mannan are the most abundant hemicellulosic polysaccharides present in cereal grain and co-product ingredients used in the livestock industry. When monogastric animals consume diets containing high amounts of AX and mannans, stimulation of GI immune cells may occur. This involves the activation of several cellular and molecular pathways of the immune system and requires a considerable amount of energy and nutrients to be expended by the animal, which may ultimately influence overall health and growth performance of animals. Therefore, a better understanding of the role of AX and mannan in immune modulation will be helpful in modulating untoward GI immune responses, thereby minimising nutrient and energy expenditure toward this effort. This review will summarise pertinent research on the role of oligosaccharides and polysaccharides containing AX and mannans in immune modulation in order to preserve gut integrity.
Topics: Animal Feed; Animal Nutritional Physiological Phenomena; Animals; Diet; Dietary Fiber; Digestion; Edible Grain; Gastrointestinal Tract; Mannans; Molecular Weight; Oligosaccharides; Polysaccharides; Solubility; Viscosity; Xylans
PubMed: 32595966
DOI: 10.1017/jns.2020.14 -
Communications Biology May 2022Common infections and polysaccharides, from bacteria and yeasts, could trigger psoriasis and psoriatic arthritis (PsA), and possibly rheumatoid arthritis (RA). The...
Common infections and polysaccharides, from bacteria and yeasts, could trigger psoriasis and psoriatic arthritis (PsA), and possibly rheumatoid arthritis (RA). The objective of this study was to investigate the effects of β-glucan polysaccharides in the effector phase of arthritis and as regulators of psoriasis and PsA-like symptoms in mice. Collagen antibody induced arthritis was studied as a model of RA and mannan-induced psoriasis (MIP) was used as model for psoriasis and PsA, using mice with a mutation of Ncf1 on the B10.Q genetic background, making them highly disease susceptible. The mice were exposed to three common variants: 1,6-β-glucan, 1,3-β-glucan and 1,3-1,6-β-glucan. These β-glucans down-regulated disease in mice if administered simultaneously, before or after mannan. Interestingly, the protection was macrophage mannose receptor (MMR/CD206) dependent with a more pronounced protection long-term than short-term. The number of resident peritoneal macrophages decreased after in vivo challenge with β-glucan and mannan compared to mannan alone, whereas the numbers of infiltrating cells correspondingly increased, further indicating macrophages as key for β-glucan mediated regulation. At the doses tested, β-glucans could not induce arthritis, psoriasis or PsA in wild-type mice. However, β-glucans could ameliorate the PsA-like symptoms representing a new unforeseen possibility to explore for future clinical treatment.
Topics: Animals; Arthritis; Glucans; Humans; Inflammation; Male; Mannans; Mice; Polysaccharides; Prostate-Specific Antigen; Psoriasis; beta-Glucans
PubMed: 35551269
DOI: 10.1038/s42003-022-03376-y -
Applied and Environmental Microbiology Feb 2022Multiple studies have found that streptococci have a synergistic relationship with species, but the details of these interactions are still being discovered. species...
Multiple studies have found that streptococci have a synergistic relationship with species, but the details of these interactions are still being discovered. species are covered by mannan, a polymer of mannose, which could serve as a carbon source for certain microbes. We hypothesized that streptococci that possess mannan-degrading glycosyl hydrolases would be able to enzymatically cleave mannose residues, which could serve as a primary carbohydrate source to support growth. We analyzed 90 streptococcus genomes to predict the capability of streptococci to transport and utilize mannose and to degrade diverse mannose linkages found on mannan. The genome analysis revealed mannose transporters and downstream pathways in most streptococci, but only <50% of streptococci harbored the glycosyl hydrolases required for mannan degradation. To confirm the ability of streptococci to use mannose or mannan, we grew 6 representative streptococci in a chemically defined medium lacking glucose supplemented with mannose, yeast extract, or purified mannan isolated from and strains. Although all tested Streptococcus strains could use mannose, Streptococcus salivarius and Streptococcus agalactiae, which did not possess mannan-degrading glycosyl hydrolases, could not use yeast extract or mannan to enhance their growth. In contrast, we found that Streptococcus mitis, Streptococcus parasanguinis, Streptococcus sanguinis, and Streptococcus pyogenes possessed the necessary glycosyl hydrolases to use yeast extract and isolated mannan, which promoted robust growth. Our data indicate that several streptococci are capable of degrading fungal mannans and harvesting mannose for energy. This work highlights a previously undescribed aspect of streptococcal interactions. Our work identifies that certain streptococci possess the enzymes required to degrade mannan, and through this mechanism, they can release mannose residues from the cell wall of fungal species and use them as a nutrient source. We speculate that streptococci that can degrade fungal mannan may have a competitive advantage for colonization. This finding has broad implications for human health, as streptococci and are found at multiple body sites.
Topics: Candida; Cell Wall; Humans; Mannans; Mannose; Streptococcus
PubMed: 34936835
DOI: 10.1128/aem.02237-21 -
Scientific Reports Oct 2021The objective of this present study was to investigate the potentiality of prebiotics (mannan oligosaccharides-MOS and fructo-oligosaccharides-FOS) in replacement of...
The objective of this present study was to investigate the potentiality of prebiotics (mannan oligosaccharides-MOS and fructo-oligosaccharides-FOS) in replacement of antibiotic growth promoter and their relationship with physico-chemical indices, antioxidant and oxidative stability and carcass traits of broiler chickens meat. Accordingly, 240 day-old broiler chicks of uniform body weight divided in 6 treatment groups with 5 replicate each (5 × 6 = 30) having 8 birds in each replicate. Six corn based dietary treatments were formulated viz. T (control diet), T (T + Bacitracin methylene di-salicylate @ 0.002%), T (T + 0.1% MOS), T (T + 0.2% MOS), T (T + 0.1% FOS), and T (T + 0.2% FOS). Significant (p < 0.05) increase in cut up part yields (%) and reduction in cholesterol and fat content in T (0.2% MOS) group. The water holding capacity (WHC) and extract release volume (ERV) were increase (p < 0.05) in 0.1 or 0.2% MOS supplemented group. DPPH (1, 1-diphenyl-2-picrylhydrazy) was higher (p < 0.05) and lipid oxidation (free fatty acid and thio-barbituric acid reactive substances) was lower (p < 0.05) in T group. The standard plate count (SPC), staphylococcus and coliform counts were decreased (p < 0.05) in T or T group. Thus, it can be concluded that mannan oligosaccharides (MOS) may be incorporated at 0.2% level in diet for improved physico-chemical indices, antioxidant and oxidative stability and carcass characteristics of broiler chickens meat and it may be suitable replacer of antibiotic growth promoter.
Topics: Animal Feed; Animal Husbandry; Animal Nutritional Physiological Phenomena; Animals; Antioxidants; Chickens; Diet; Dietary Supplements; Lipid Metabolism; Mannans; Meat; Oligosaccharides; Oxidation-Reduction; Oxidative Stress; Prebiotics
PubMed: 34663866
DOI: 10.1038/s41598-021-99620-2 -
Clinical and Experimental Immunology Mar 2023Psoriasis is a genetically determined, environmentally triggered, immune system-mediated autoimmune disease. Different animal models are needed to investigate the...
Psoriasis is a genetically determined, environmentally triggered, immune system-mediated autoimmune disease. Different animal models are needed to investigate the complex pathological mechanisms underlying this disease. Therefore, we established mannan-induced psoriasis model and compared with the most commonly used imiquimod-induced psoriasis in terms of disease, induction of innate immune cells, expression of cytokines, and the effect of dexamethasone treatment. Mannan significantly induced more severe psoriasis with better disease relapsing feature than imiquimod (IMQ). As determined by immunohistochemistry, IMQ induced significantly more infiltration of CD11c+ and F4/80+ cells than mannan in the skin. However, cytometric analysis showed a significant increase in the percentage of Gr-1+ neutrophils in the spleen and lymph nodes as well as F4/80+ macrophages in the spleen after mannan exposure. Variation in the percentage of significantly increased Vγ4 T cells was also found to be dependent on the lymphoid organs tested. However, there is a clear difference between these models in terms of expression of certain cytokine genes: IL-22, IL-23, IL-17E, and IL-17F were expressed more predominantly in mannan-induced inflammation, while IL-6 and IL-17A expressions were significantly higher in IMQ model. Interestingly, dexamethasone treatment strongly reduced epidermal thickness and histological scores induced by mannan than IMQ. Despite inducing psoriasis-like inflammation, certain differences and similarities were observed in the immune responses induced by mannan and IMQ. However, mannan-induced psoriasis model is relatively more simple, economical and less harmful to mice with an increased possibility to develop a chronic psoriasis model by exposing mice to mannan.
Topics: Mice; Animals; Imiquimod; Mannans; Disease Models, Animal; Psoriasis; Skin; Inflammation; Dexamethasone; Mice, Inbred BALB C
PubMed: 36645209
DOI: 10.1093/cei/uxad004 -
Poultry Science Mar 2014A germ-free (GF) chicken model was used to test 2 hypotheses: 1. microbial colonization of the gastrointestinal tract (GIT) influences mucin gene expression and mucin...
A germ-free (GF) chicken model was used to test 2 hypotheses: 1. microbial colonization of the gastrointestinal tract (GIT) influences mucin gene expression and mucin types; and 2. mannan oligosaccharide (MOS) supplementation affects GIT cells directly, without bacteria mediation, compared with bacterial-mediated effect (i.e., indirectly). Gnotobiotic isolators were used: 1) GF, 2) with a single bacteria population, and 3) conventionalized by exposure to cecal bacterial contents. Each was divided to 2 diet groups: with or without MOS (2 kg/t) for 1 wk. Results show that the absence of bacteria in the GIT caused a reduction in neutral and acidic goblet cell (GC) number and density, an increase in sulfated mucin, absence of sialylated GC, and reduced mucin 2 mRNA expression in the small intestine of GF compared with conventional birds. These results indicate a reduced development of mucin production and secretion in the absence of GIT bacteria implying a less mature small intestine mucosa, supporting our first hypothesis. Results from the single bacteria population group were not conclusive and did not support any of the hypotheses. Supplementation of MOS, regardless of microbial presence, caused a reduction in neutral GC number and density but increased neutral GC area. The MOS caused different effects on acidic mucins in conventional and GF birds, causing a reduction in sialylated GC number (conventional) and a reduction in sulfated GC density (GF), all supporting a direct effect of MOS in GF animals, in addition to an indirect effect via gut microflora.
Topics: Animal Feed; Animals; Avian Proteins; Cecum; Chickens; Colony Count, Microbial; Diet; Dietary Supplements; Gastrointestinal Tract; Germ-Free Life; Mannans; Microbiota; Mucins; Oligosaccharides; Real-Time Polymerase Chain Reaction
PubMed: 24604857
DOI: 10.3382/ps.2013-03362