scholarly journals Limited Hydrolysis of Polysialic Acid by Human Neuraminidase Enzymes

2021 ◽  
Author(s):  
Carmanah D. Hunter ◽  
Christopher Cairo
Keyword(s):  
Polysialic Acid ◽  
Chemical Properties ◽  
Sialic Acids ◽  
Degree Of Polymerization ◽  
Health And Disease ◽  
Substrate Tolerance ◽  
The Impact ◽  
Hydrolysis Of ◽  
Unique Chemical

Regulation of sialic acids by human neuraminidase (hNEU) enzymes is important to many biological processes. Defining hNEU substrate tolerance can help to elucidate the roles of these enzymes in regulating sialosides in human health and disease. Polysialic acid (polySia) is a polyanion of α(2→8) linked sialic acids with roles in nervous, reproductive, and immune systems and is dysregulated in some malignancies and mental disorders. The unique chemical properties of this polymer, which include an enhanced susceptibility to acid-catalyzed hydrolysis, have hampered its study. Herein we describe the first<i> </i>systematic study of hNEU isoenzyme activity towards polysialic acid <i>in vitro.</i> The experimental design allowed us to study the impact of several factors that may influence polysialic acid degradation including pH, polymer size, and the relative ionic strength of the surrounding media. We report that short chains of polysialic acid (degree of polymerization, DP 3-8) were substrates of NEU3 and NEU4 at acidic pH, but not at neutral pH. No hNEU-catalyzed hydrolysis of longer polymers (DP 10-20) was detected. These findings suggest a neuraminidase-independent mechanism for polysialic acid turnover such as internalization and degradation in endosomes and lysosomes.

scholarly journals Limited Hydrolysis of Polysialic Acid by Human Neuraminidase Enzymes

2021 ◽  
Author(s):  
Carmanah D. Hunter ◽  
Christopher Cairo
Keyword(s):  
Polysialic Acid ◽  
Chemical Properties ◽  
Sialic Acids ◽  
Degree Of Polymerization ◽  
Health And Disease ◽  
Substrate Tolerance ◽  
The Impact ◽  
Hydrolysis Of ◽  
Unique Chemical

Regulation of sialic acids by human neuraminidase (hNEU) enzymes is important to many biological processes. Defining hNEU substrate tolerance can help to elucidate the roles of these enzymes in regulating sialosides in human health and disease. Polysialic acid (polySia) is a polyanion of α(2→8) linked sialic acids with roles in nervous, reproductive, and immune systems and is dysregulated in some malignancies and mental disorders. The unique chemical properties of this polymer, which include an enhanced susceptibility to acid-catalyzed hydrolysis, have hampered its study. Herein we describe the first<i> </i>systematic study of hNEU isoenzyme activity towards polysialic acid <i>in vitro.</i> The experimental design allowed us to study the impact of several factors that may influence polysialic acid degradation including pH, polymer size, and the relative ionic strength of the surrounding media. We report that short chains of polysialic acid (degree of polymerization, DP 3-8) were substrates of NEU3 and NEU4 at acidic pH, but not at neutral pH. No hNEU-catalyzed hydrolysis of longer polymers (DP 10-20) was detected. These findings suggest a neuraminidase-independent mechanism for polysialic acid turnover such as internalization and degradation in endosomes and lysosomes.

scholarly journals A review on the bio-functional roles of phospholipids from marine resources

Food Research ◽  
2021 ◽  
Vol 5 (5) ◽  
pp. 1-16
Author(s):  
M. Haq ◽  
S. Suraiya
Keyword(s):  
Synergistic Effects ◽  
Chemical Properties ◽  
Functional Roles ◽  
Functional Activities ◽  
Marine Phospholipids ◽  
Liver Functions ◽  
Anti Inflammatory ◽  
Unique Chemical

Marine phospholipids (PLs) rich in ω-3 polyunsaturated fatty acids (ω-3 PUFAs) have drawn keen interest recently among researchers and consumers and could be assumed as a “miracle drug”. Substantial amount of EPA and DHA, amazing and unique chemical properties and super bio-functional activities of marine PLs make it superior compared to terrestrial PLs, which lack long chain ω-3 PUFAs. Many comparative studies revealed that marine PLs showed higher health beneficial activities compared to PLs obtained from land sources. Marine PLs are not only beneficial in containing a high amount of ω-3 PUFAs but also in absorbing and assimilating ω-3 PUFAs in different tissues. Synergistic effects of PL compounds and ω-3 PUFAs in marine PLs showed super bio-functional performances like anti-atherosis and cardioprotective, anti-inflammatory, neuroprotective, immunological, and liver functions. A number of in vivo and in vitro studies on the administration of marine PLs extracted from fishes, mollusks, crustaceans, echinoderms reduced triacylglycerol (TAG) level and enhanced cardioprotective functions, demonstrated anti-inflammatory activity, reduced cell proliferation and tumor, increased cognitive functions and memory, and prevented hepatic damages. Therefore, this review paper provides detailed accounts on the present research status of critical biological and nutritional functions of marine ω-3 PUFAs rich phospholipids focusing on the origin, animal models, treatment, and roles.

scholarly journals H.p.l.c. of oligo(sialic acids). Application to the determination of the minimal chain length serving as exogenous acceptor in the enzymic synthesis of colominic acid

1991 ◽  
Vol 280 (3) ◽  
pp. 575-579 ◽  
Author(s):  
M A Ferrero ◽  
J M Luengo ◽  
A Reglero
Keyword(s):  
Chain Length ◽  
Complete Separation ◽  
Sialic Acids ◽  
Degree Of Polymerization ◽  
Direct Transfer ◽  
Maximal Rate ◽  
Colominic Acid ◽  
Membrane Bound

A rapid, sensitive and easy h.p.l.c. method was developed for the quantitative analysis of oligosialic acids. This procedure which permits the complete separation (in 23 min) of several sialyloligomers with a degree of polymerization of between 1 and 16, has been employed to establish the minimal chain length of oligomer accepted, as an exogenous acceptor, by Escherichia coli K-235 sialytransferase complex (ST) leading to the synthesis in vitro of colominic acid. We showed that this membrane-bound enzyme catalyses the direct transfer of Neu5Ac residues (one by one) from CMP-Neu5Ac to an exogenous acceptor molecule which contains at least three Neu5Ac residues. Free Neu5Ac or (Neu5Ac)2 were not recognized as substrates, whereas the maximal rate of polymer elongation was achieved when (Neu5Ac)5 was used as substrate.

scholarly journals Fermented Foods: Definitions and Characteristics, Impact on the Gut Microbiota and Effects on Gastrointestinal Health and Disease

Nutrients ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1806 ◽  
Author(s):  
Eirini Dimidi ◽  
Selina Rose Cox ◽  
Megan Rossi ◽  
Kevin Whelan
Keyword(s):  
Controlled Trial ◽  
Health Benefits ◽  
Biologically Active ◽  
Fermented Foods ◽  
Lactose Malabsorption ◽  
Gastrointestinal Health ◽  
Sourdough Bread ◽  
Health And Disease ◽  
The Impact

Fermented foods are defined as foods or beverages produced through controlled microbial growth, and the conversion of food components through enzymatic action. In recent years, fermented foods have undergone a surge in popularity, mainly due to their proposed health benefits. The aim of this review is to define and characterise common fermented foods (kefir, kombucha, sauerkraut, tempeh, natto, miso, kimchi, sourdough bread), their mechanisms of action (including impact on the microbiota), and the evidence for effects on gastrointestinal health and disease in humans. Putative mechanisms for the impact of fermented foods on health include the potential probiotic effect of their constituent microorganisms, the fermentation-derived production of bioactive peptides, biogenic amines, and conversion of phenolic compounds to biologically active compounds, as well as the reduction of anti-nutrients. Fermented foods that have been tested in at least one randomised controlled trial (RCT) for their gastrointestinal effects were kefir, sauerkraut, natto, and sourdough bread. Despite extensive in vitro studies, there are no RCTs investigating the impact of kombucha, miso, kimchi or tempeh in gastrointestinal health. The most widely investigated fermented food is kefir, with evidence from at least one RCT suggesting beneficial effects in both lactose malabsorption and Helicobacter pylori eradication. In summary, there is very limited clinical evidence for the effectiveness of most fermented foods in gastrointestinal health and disease. Given the convincing in vitro findings, clinical high-quality trials investigating the health benefits of fermented foods are warranted.

scholarly journals Evaluation of Preventive Fungicide Applications for Fairy Ring Control in Golf Putting Greens and In Vitro Sensitivity of Fairy Ring Species to Fungicides

Plant Disease ◽  
2012 ◽  
Vol 96 (7) ◽  
pp. 1001-1007 ◽  
Author(s):  
G. L. Miller ◽  
M. D. Soika ◽  
L. P. Tredway
Keyword(s):  
Soil Temperature ◽  
Field Experiments ◽  
Chemical Properties ◽  
Creeping Bentgrass ◽  
Fungicide Sensitivity ◽  
Putting Greens ◽  
Growth Assay ◽  
Ring Species ◽  
The Impact

Fairy ring species induce symptoms on putting greens mostly indirectly, by modifying the soil physical or chemical properties. Therefore, preventive rather than curative fungicide applications may be more effective in managing fairy ring. Two field experiments were conducted on a creeping bentgrass research green to evaluate fairy ring control from preventive fungicide applications. A 3-year study investigated the optimal rate and soil temperature-based timing of a preventive application of triadimefon and tebuconazole. A 2-year study evaluated the impact of irrigation timing and fungicide + surfactant tank mixtures on the efficacy of preventive applications of triadimefon and triticonazole. Fungicide-treated plots in both studies exhibited less fairy ring severity than untreated plots. Data suggest that a 5-day average soil temperature range of 13 to 16°C may be suitable for initiating preventive applications. Symptoms occurred earlier in plots treated with a surfactant tank mix than in those treated with fungicide alone. Irrigation timing had no effect on fungicide performance. The sensitivity of 16 isolates representing major fairy ring species to flutolanil, propiconazole, tebuconazole, triadimefon, and triticonazole was determined with a mycelial growth assay. No significant differences in fungicide sensitivity were detected among species. Isolates had significantly higher 50% effective concentration values for triadimefon than for the other fungicides tested.

scholarly journals Prebiotic Potential of Oligosaccharides Obtained by Acid Hydrolysis of α-(1→3)-Glucan from Laetiporus sulphureus: A Pilot Study

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5542
Author(s):  
Adrian Wiater ◽  
Adam Waśko ◽  
Paulina Adamczyk ◽  
Klaudia Gustaw ◽  
Małgorzata Pleszczyńska ◽  
...  
Keyword(s):  
Acid Hydrolysis ◽  
Well Being ◽  
Degree Of Polymerization ◽  
Intestinal Microbiome ◽  
Bacterial Strains ◽  
Laetiporus Sulphureus ◽  
Pure Cultures ◽  
Hydrolysis Of

Increasing knowledge of the role of the intestinal microbiome in human health and well-being has resulted in increased interest in prebiotics, mainly oligosaccharides of various origins. To date, there are no reports in the literature on the prebiotic properties of oligosaccharides produced by the hydrolysis of pure fungal α-(1→3)-glucan. The aim of this study was to prepare α-(1→3)-glucooligosaccharides (α-(1→3)-GOS) and to perform initial evaluation of their prebiotic potential. The oligosaccharides were obtained by acid hydrolysis of α-(1→3)-glucan isolated from the fruiting bodies of Laetiporus sulphureus and then, characterized by HPLC. Fermentation of α-(1→3)-GOS and reference prebiotics was compared in in vitro pure cultures of Lactobacillus, Bifidobacterium, and enteric bacterial strains. A mixture of α-(1→3)-GOS, notably with a degree of polymerization of 2 to 9, was obtained. The hydrolysate was utilized for growth by most of the Lactobacillus strains tested and showed a strong bifidogenic effect, but did not promote the growth of Escherichia coli and Enterococcus faecalis. α-(1→3)-GOS proved to be effective in the selective stimulation of beneficial bacteria and can be further tested to determine their prebiotic functionality.

scholarly journals The Puzzling Potential of Carbon Nanomaterials: General Properties, Application, and Toxicity

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1508
Author(s):  
Danica Jović ◽  
Vesna Jaćević ◽  
Kamil Kuča ◽  
Ivana Borišev ◽  
Jasminka Mrdjanovic ◽  
...  
Keyword(s):  
Carbon Nanomaterials ◽  
Wide Spectrum ◽  
Chemical Properties ◽  
Carbon Nanomaterial ◽  
In Vivo Models ◽  
Physico Chemical ◽  
The Impact ◽  
Cell Signaling Pathways

Being a member of the nanofamily, carbon nanomaterials exhibit specific properties that mostly arise from their small size. They have proved to be very promising for application in the technical and biomedical field. A wide spectrum of use implies the inevitable presence of carbon nanomaterials in the environment, thus potentially endangering their whole nature. Although scientists worldwide have conducted research investigating the impact of these materials, it is evident that there are still significant gaps concerning the knowledge of their mechanisms, as well as the prolonged and chronic exposure and effects. This manuscript summarizes the most prominent representatives of carbon nanomaterial groups, giving a brief review of their general physico-chemical properties, the most common use, and toxicity profiles. Toxicity was presented through genotoxicity and the activation of the cell signaling pathways, both including in vitro and in vivo models, mechanisms, and the consequential outcomes. Moreover, the acute toxicity of fullerenol, as one of the most commonly investigated members, was briefly presented in the final part of this review. Thinking small can greatly help us improve our lives, but also obliges us to deeply and comprehensively investigate all the possible consequences that could arise from our pure-hearted scientific ambitions and work.

scholarly journals Utilization of a Model Cocoa Fermentation System and Roasting to Assess Differences Among Bioactive Compounds and Bioactivity of Cocoa Through Variable Processing Conditions (FS07-04-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Kathryn Racine ◽  
Brian Wiersema ◽  
Andrew Lee ◽  
Laura Griffin ◽  
Lauren Essenmacher ◽  
...  
Keyword(s):  
Degree Of Polymerization ◽  
Control Treatment ◽  
Cocoa Bean ◽  
Cocoa Beans ◽  
Cocoa Powder ◽  
Funding Sources ◽  
Food Research ◽  
The Impact

Abstract Objectives Cocoa beans (Theobroma cacao) are a highly concentrated source of dietary flavanols that undergo processing steps, to enhance sensory characteristics. Although it is widely accepted that preservation of native cocoa flavanols is critical for retaining bioactivity, it is possible that reactions occurring throughout cocoa processing may generate compounds with novel activities, potentially preserving or enhancing bioactivity. Our objective was to evaluate the impact of fermentation and roasting on levels of flavanols and bioactivity of cocoa. Methods Combinations of fermentation and roasting parameters were employed via a controlled laboratory fermentation model system and roasting operation. Cocoa powders were produced from unfermented cocoa beans using different treatments representing extremes of fermentation and roasting. Cocoa beans were fermented in a simulated pulp media for 168 h. Fermentation and roasting temperatures varied depending on treatment group. Further processing (winnowing, grinding, pressing) produced cocoa powders for each treatment. Extracts were made from the final beans and powders. Total polyphenols were quantified by the Folin-Ciocalteu assay. HILIC UPLC-MS/MS was employed to analyze flavanols based on their degree of polymerization (DP). Results Fermentation and roasting contributed to losses of native flavanols. Total polyphenol levels and individual flavanols (DP 1–10) were approximately 27–90% lower in hot fermented/hot roasted cocoa powder and approximately 11–54% lower in cool fermented/cool roasted cocoa powder when compared to the unfermented/unroasted (control) treatment. Hot roasting had the most significant impact on flavanol degradation. There was also a direct relationship between increasing flavanol concentration in cocoa powder and DP. Conclusions Compared to fermentation, roasting demonstrated a more significant impact on flavanol degradation and composition among cocoa bean treatments. Further research in vitro and in vivo is being performed currently to determine whether these process-induced flavanol losses correlate with reduced anti-obesity and anti-inflammatory activities. Funding Sources This work was supported by the Agriculture and Food Research Initiative (AFRI) of the US Department of Agriculture.

In vitro ruminal digestibility of oat hay and cellulolytic activity in the presence of increasing concentrations of short-chain acids and glycerol

2004 ◽  
Vol 142 (1) ◽  
pp. 89-96 ◽  
Author(s):  
R. A. PAGGI ◽  
J. P. FAY ◽  
C. FAVERIN
Keyword(s):  
Acetic Acid ◽  
Ionic Strength ◽  
Conformational Changes ◽  
Rumen Fluid ◽  
Short Chain ◽  
Cellulolytic Activity ◽  
The Impact ◽  
Lactic Acids ◽  
Hydrolysis Of

The effects of acetic, propionic, butyric and lactic acids (short-chain acids), and of glycerol, on the in vitro dry matter digestibility (IVDMD) of oat hay, and on cellulolysis by a protein extract of rumen fluid were studied. The objective was to gain information on the impact of increasing the concentrations of those compounds in the medium on degradative activities carried out by rumen microorganisms. Short-chain acids were assayed as sodium salts and, for all compounds, the concentrations were 50, 100, 200 and 300 mM. The volatile fatty acids (VFA: acetic, propionic and butyric acids) were tested separately or in two mixtures A and B that contained different proportions of each VFA. The IVDMD was assayed according to a modified Tilley & Terry (1963) technique while cellulolysis was assessed by the hydrolysis of carboxymethylcellulose (CMC) in 1-h incubations at 39 °C. Parallel incubations with NaCl were utilized as controls for ionic strength and osmolarity changes in the incubation medium. Increases of 100–300 mM of short-chain acids decreased IVDMD between 7 and 39%. The inhibitions produced by increases of 200 and 300 mM of acetic acid were smaller than those caused by the same concentrations of either butyric or lactic acids. Increases of 100, 200 and 300 mM of glycerol reduced by 8–15% the IVDMD, and the inhibitions produced by increments of 200 and 300 mM of this compound were smaller than the ones elicited by the short-chain acids, with the exception of 200 mM of acetic acid that did not differ. The IVDMD was inhibited by NaCl only when concentrations were increased by 200 (12%) and 300 mM (26%). The degradation of CMC was reduced by 7–20% by 200 and 300 mM increases of the short-chain acids or glycerol, the exception being lactic acid that had no effect. One hundred mM increases of acetic and butyric acids inhibited the CMC degradation by 7 and 9%, respectively, whereas only butyric acid was inhibitory (7%) at 50 mM. Greater concentration increases of both VFA mixtures A and B than of the individual VFA were necessary to inhibit the hydrolysis of CMC. Cellulolytic activity was decreased 6 and 9% by increases of 200 and 300 mM of NaCl, respectively, and these drops of activity were smaller than those obtained with increases in any of the other compounds. Since osmolarity and/or ionic strength changes in the medium cannot completely account for the observed inhibitions of IVDMD and cellulolysis, it is suggested that glycerol and the anions of short-chain acids produce changes in the reaction media polarity that contribute to the inhibitory effects observed. Alterations in the media could also bring about conformational changes in the degradative enzymes leading to reduced rates of reaction and subsequent decreases in IVDMD and cellulolysis. Since most of the effects were observed with concentration increases that were larger than the physiological concentrations in the rumen, it is suggested that the compounds tested have little impact in vivo on the ruminal degradative activities that were evaluated.

The impact of hydrophilic emulsifiers on the physico-chemical properties, microstructure, water distribution and in vitro digestibility of proteins in fried snacks based on fish meat

2019 ◽  
Vol 10 (10) ◽  
pp. 6927-6935 ◽  
Author(s):  
Asad Nawaz ◽  
Zhouyi Xiong ◽  
Hanguo Xiong ◽  
Sana Irshad ◽  
Lei Chen ◽  
...  
Keyword(s):  
Protein Interaction ◽  
Water Distribution ◽  
Chemical Properties ◽  
In Vitro Digestibility ◽  
Fish Meat ◽  
Physico Chemical ◽  
The Impact

Hydrophillic emulsifiers strengthened the starch–protein interaction which resulted in improved physio-chemical properties of friend snacks based on fish meat.

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