scholarly journals Use of a Glycan Library Reveals a New Model for Enteric Virus Oligosaccharide Binding and Virion Stabilization

2019 ◽  
Vol 94 (6) ◽  
Author(s):  
Hua Lu ◽  
Mark A. Lehrman ◽  
Julie K. Pfeiffer
Keyword(s):  
Gastrointestinal Tract ◽  
Enteric Viruses ◽  
Enteric Virus ◽  
Oral Route ◽  
Environmental Stability ◽  
Fold Axis ◽  
Glycan Chain ◽  
Viral Surface ◽  
Insight Into ◽  
Long Chain

ABSTRACT Enteric viruses infect the gastrointestinal tract, and bacteria can promote replication and transmission of several enteric viruses. Viruses can be inactivated by exposure to heat or bleach, but poliovirus, coxsackievirus B3, and reovirus can be stabilized by bacteria or bacterial polysaccharides, limiting inactivation and aiding transmission. We previously demonstrated that certain N-acetylglucosamine (GlcNAc)-containing polysaccharides can stabilize poliovirus. However, the detailed virus-glycan binding specificity and glycan chain length requirements, and thus the mechanism of virion stabilization, have been unclear. A previous limitation was our lack of defined-length glycans to probe mechanisms and consequences of virus-glycan interactions. Here, we generated a panel of polysaccharides and oligosaccharides to determine the properties required for binding and stabilization of poliovirus. Poliovirus virions are nonenveloped icosahedral 30-nm particles with 60 copies of each of four capsid proteins, VP1 to VP4. VP1 surrounds the 5-fold axis, and our past work indicates that this region likely contains the glycan binding site. We found that relatively short GlcNAc oligosaccharides, such as a six-unit GlcNAc oligomer, can bind poliovirus but fail to enhance virion stability. Virion stabilization required binding of long GlcNAc polymers of greater than 20 units. Our data suggest a model where GlcNAc polymers of greater than 20 units bind and bridge adjacent 5-fold axes, thus aiding capsid rigidity and stability. This study provides a deeper understanding of enteric virus-bacterial glycan interactions, which are important for virion environmental stability and transmission. IMPORTANCE Enteric viruses are transmitted through the fecal-oral route, but how enteric viruses survive in the environment is unclear. Previously, we found that bacterial polysaccharides enhance poliovirus stability against heat or bleach inactivation, but the specific molecular requirements have been unknown. Here, we showed that certain short-chain oligosaccharides can bind to poliovirus but do not increase virion stability. Long-chain polysaccharides bind and may bridge adjacent sites on the viral surface, thus increasing capsid rigidity and stability. This work defines the unique interactions of poliovirus and glycans, which provides insight into virion environmental stability and transmission.

scholarly journals Use of a glycan library reveals a new model for enteric virus oligosaccharide binding and virion stabilization

2019 ◽  
Author(s):  
Hua Lu ◽  
Mark A. Lehrman ◽  
Julie K. Pfeiffer
Keyword(s):  
Gastrointestinal Tract ◽  
Binding Site ◽  
Enteric Viruses ◽  
Enteric Virus ◽  
Oral Route ◽  
Environmental Stability ◽  
Glycan Chain ◽  
Viral Surface ◽  
Insight Into ◽  
Long Chain

AbstractEnteric viruses infect the gastrointestinal tract and bacteria can promote replication and transmission of several enteric viruses. Viruses can be inactivated by exposure to heat or bleach, but poliovirus, coxsackievirus B3, and reovirus can be stabilized by bacteria or bacterial polysaccharides, limiting inactivation and aiding transmission. We previously demonstrated that certain N-acetylglucosamine (GlcNAc)-containing polysaccharides can stabilize poliovirus. However, the detailed virus-glycan binding specificity and glycan chain length requirements, and thus the mechanism of virion stabilization, has been unclear. A previous limitation was our lack of defined-length glycans to probe mechanisms and consequences of virus-glycan interactions. Here, we generated a panel of polysaccharides and oligosaccharides to determine the properties required for binding and stabilization of poliovirus. Poliovirus virions are non-enveloped icosahedral 30 nm particles with 60 copies of each of four capsid proteins, VP1-4. VP1 surrounds the fivefold axis and our past work indicates that this region likely contains the glycan binding site. We found that relatively short GlcNAc oligosaccharides, such as a six unit GlcNAc oligomer, can bind poliovirus but fail to enhance virion stability. Virion stabilization required binding of long GlcNAc polymers of greater than 20 units. Our data suggest a model where GlcNAc polymers greater than 20 units bind and bridge adjacent fivefold axes, thus aiding capsid rigidity and stability. This study provides a deeper understanding of enteric virus-bacterial glycan interactions, which is important for virion environmental stability and transmission.ImportanceEnteric viruses are transmitted through the fecal-oral route, but how enteric viruses survive in the environment is unclear. Previously, we found that bacterial polysaccharides enhance poliovirus stability against heat or bleach inactivation, but the specific molecular requirements have been unknown. Here we showed that certain short chain oligosaccharides can bind to poliovirus but do not increase virion stability. Long chain polysaccharides bind and may bridge adjacent sites on the viral surface, thus increasing capsid rigidity and stability. This work defines the unique interactions of poliovirus and glycans, which provides insight into virion environmental stability and transmission.

scholarly journals The Antibiotic Neomycin Enhances Coxsackievirus Plaque Formation

mSphere ◽  
2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Mikal A. Woods Acevedo ◽  
Andrea K. Erickson ◽  
Julie K. Pfeiffer
Keyword(s):  
Gastrointestinal Tract ◽  
Cultured Cells ◽  
Enteric Viruses ◽  
Aminoglycoside Antibiotic ◽  
Enteric Virus ◽  
Plaque Formation ◽  
Sulfated Polysaccharides ◽  
Intestinal Microbes ◽  
Viral Attachment ◽  
Positively Charged

ABSTRACTCoxsackievirus typically infects humans via the gastrointestinal tract, which has a large number of microorganisms collectively referred to as the microbiota. To study how the intestinal microbiota influences enteric virus infection, several groups have used an antibiotic regimen in mice to deplete bacteria. These studies have shown that bacteria promote infection with several enteric viruses. However, very little is known about whether antibiotics influence viruses in a microbiota-independent manner. In this study, we sought to determine the effects of antibiotics on coxsackievirus B3 (CVB3) using anin vitrocell culture model in the absence of bacteria. We determined that an aminoglycoside antibiotic, neomycin, enhanced the plaque size of CVB3 strain Nancy. Neomycin treatment did not alter viral attachment, translation, or replication. However, we found that the positive charge of neomycin and other positively charged compounds enhanced viral diffusion by overcoming the negative inhibitory effect of sulfated polysaccharides present in agar overlays. Neomycin and the positively charged compound protamine also enhanced plaque formation of reovirus. Overall, these data provide further evidence that antibiotics can play noncanonical roles in viral infections and that this should be considered when studying enteric virus-microbiota interactions.IMPORTANCECoxsackieviruses primarily infect the gastrointestinal tract of humans, but they can disseminate systemically and cause severe disease. Using antibiotic treatment regimens to deplete intestinal microbes in mice, several groups have shown the bacteria promote infection with a variety of enteric viruses. However, it is possible that antibiotics have microbiota-independent effects on viruses. Here we show that an aminoglycoside antibiotic, neomycin, can influence quantification of coxsackievirus in cultured cells in the absence of bacteria.

scholarly journals The Antibiotic Neomycin Enhances Coxsackievirus Plaque Formation

2018 ◽  
Author(s):  
Mikal A. Woods Acevedo ◽  
Julie K. Pfeiffer
Keyword(s):  
Gastrointestinal Tract ◽  
Cultured Cells ◽  
Severe Disease ◽  
Enteric Viruses ◽  
Aminoglycoside Antibiotic ◽  
Enteric Virus ◽  
Sulfated Polysaccharides ◽  
Independent Manner ◽  
Intestinal Microbes ◽  
Viral Attachment

AbstractCoxsackievirus typically infects humans via the gastrointestinal tract, which has a large number of microorganisms collectively referred to as the microbiota. To study how the intestinal microbiota influence enteric virus infection, several groups have used an antibiotic regimen in mice to deplete bacteria. These studies have shown that bacteria promote infection with several enteric viruses. However, very little is known about whether antibiotics influence viruses in a microbiota-independent manner. Here, we sought to determine the effects of antibiotics on coxsackievirus B3 (CVB3) using anin vitrocell culture model in the absence of bacteria. We determined that an aminoglycoside antibiotic, neomycin, enhanced plaque size of CVB3-Nancy strain. Neomycin treatment did not alter viral attachment, translation, or replication. However, we found that the positive charge of neomycin and other positively charged compounds enhanced viral diffusion by overcoming the negative inhibitory effect of sulfated polysaccharides present in agar overlays. Overall, these data lend further evidence that antibiotics can play non-canonical roles in viral infections and that this should be considered when studying enteric virus-microbiota interactions.ImportanceCoxsackieviruses primarily infect the gastrointestinal tract of humans, but they can disseminate systemically and cause severe disease. Using antibiotic treatment regimens to deplete intestinal microbes in mice, several groups have shown the bacteria promote infection with a variety of enteric viruses. However, it is possible that antibiotics have microbiota-independent effects on viruses. Here, we show that an aminoglycoside antibiotic, neomycin, can influence quantification of coxsackievirus in cultured cells in absence of bacteria.

Enteric viruses in drinking water supplies

2002 ◽  
Vol 2 (3) ◽  
pp. 17-22
Author(s):  
A.P. Wyn-Jones ◽  
J. Watkins ◽  
C. Francis ◽  
M. Laverick ◽  
J. Sellwood
Keyword(s):  
Drinking Water ◽  
Heavy Rainfall ◽  
Liquid Culture ◽  
Plaque Assay ◽  
Enteric Viruses ◽  
Enteric Virus ◽  
The Other ◽  
Raw Water ◽  
Rt Pcr ◽  
Water Supplies

Two rural spring drinking water supplies were studied for their enteric virus levels. In one, serving about 30 dwellings, the water was chlorinated before distribution; in the other, which served a dairy and six dwellings the water was not treated. Samples of treated (40 l) and untreated (20 l) water were taken under normal and heavy rainfall conditions over a six weeks period and concentrated by adsorption/elution and organic flocculation. Infectious enterovirus in concentrates was detected in liquid culture and enumerated by plaque assay, both in BGM cells, and concentrates were also analysed by RT-PCR. Viruses were found in both raw water supplies. Rural supplies need to be analysed for viruses as well as bacterial and protozoan pathogens if the full microbial hazard is to be determined.

scholarly journals Assessing the Occurrence of Waterborne Viruses in Reuse Systems: Analytical Limits and Needs

Pathogens ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 107 ◽  
Author(s):  
Charles P. Gerba ◽  
Walter Q. Betancourt
Keyword(s):  
Cell Culture ◽  
Virus Detection ◽  
Enteric Viruses ◽  
Enteric Virus ◽  
Culture Cell ◽  
Virus Infectivity ◽  
Recycled Water ◽  
Chemical Additives ◽  
Potable Reuse ◽  
Passage Number

Detection of waterborne enteric viruses is an essential tool in assessing the risk of waterborne transmission. Cell culture is considered a gold standard for detection of these viruses. However, it is important to recognize the uncertainty and limitations of enteric virus detection in cell culture. Cell culture cannot support replication of all virus types and strains, and numerous factors control the efficacy of specific virus detection assays, including chemical additives, cell culture passage number, and sequential passage of a sample in cell culture. These factors can result in a 2- to 100-fold underestimation of virus infectivity. Molecular methods reduce the time for detection of viruses and are useful for detection of those that do not produce cytopathogenic effects. The usefulness of polymerase chain reaction (PCR) to access virus infectivity has been demonstrated for only a limited number of enteric viruses and is limited by an understanding of the mechanism of virus inactivation. All of these issues are important to consider when assessing waterborne infectious viruses and expected goals on virus reductions needed for recycled water. The use of safety factors to account for this may be useful to ensure that the risks in drinking water and recycled water for potable reuse are minimized.

scholarly journals Enteric Viruses and Inflammatory Bowel Disease

Viruses ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 104
Author(s):  
Georges Tarris ◽  
Alexis de Rougemont ◽  
Maëva Charkaoui ◽  
Christophe Michiels ◽  
Laurent Martin ◽  
...  
Keyword(s):  
Association Studies ◽  
Enteric Viruses ◽  
Enteric Virus ◽  
Viral Gastroenteritis ◽  
Blood Group Antigens ◽  
Genome Wide Association Studies ◽  
Virus Infections ◽  
T Helper ◽  
Inflammatory Bowel

Inflammatory bowel diseases (IBD), including ulcerative colitis (UC) and Crohn’s disease (CD), is a multifactorial disease in which dietary, genetic, immunological, and microbial factors are at play. The role of enteric viruses in IBD remains only partially explored. To date, epidemiological studies have not fully described the role of enteric viruses in inflammatory flare-ups, especially that of human noroviruses and rotaviruses, which are the main causative agents of viral gastroenteritis. Genome-wide association studies have demonstrated the association between IBD, polymorphisms of the FUT2 and FUT3 genes (which drive the synthesis of histo-blood group antigens), and ligands for norovirus and rotavirus in the intestine. The role of autophagy in defensin-deficient Paneth cells and the perturbations of cytokine secretion in T-helper 1 and T-helper 17 inflammatory pathways following enteric virus infections have been demonstrated as well. Enteric virus interactions with commensal bacteria could play a significant role in the modulation of enteric virus infections in IBD. Based on the currently incomplete knowledge of the complex phenomena underlying IBD pathogenesis, future studies using multi-sampling and data integration combined with new techniques such as human intestinal enteroids could help to decipher the role of enteric viruses in IBD.

DETERMINATION OF THE OPTIMAL CONCENTRATIONS OF PECTIN AND CALCIUM CHLORIDE FOR THE SYNTHESIS OF CHITOSAN-PECTIN MICROPARTICLES

2021 ◽  
Author(s):  
Alla Krasnoshtanova ◽  
Anastasiya Bezyeva
Keyword(s):  
Drug Delivery ◽  
Gastrointestinal Tract ◽  
Calcium Chloride ◽  
Active Substance ◽  
Drug Delivery Systems ◽  
Oral Drug Delivery ◽  
Oral Route ◽  
Delivery Systems ◽  
Oral Drug ◽  
Oral Drug Delivery Systems

"The oral route of drug inclusion is the most convenient for the patient. In addition to ease of use, this method of drug inclusion has such advantages as non-invasiveness of inclusion, absence of complications during injection; comparative safety for the organism due to the passage of the active substance and auxiliary compounds through the gastrointestinal tract; the possibility of introducing larger doses of the drug at one time. However, despite the obvious advantages, the oral route of inclusion has a number of significant disadvantages that significantly limit its use for a number of drugs. Among them are: relatively slow therapeutic action of the drug with this route of inclusion; the aggressive effect of a number of drugs (for example, antibiotics) on the gastrointestinal tract; low bioavailability of a number of substances (especially high molecular weight hydrophilic compounds), caused by poor permeability of the intestinal epithelium for hydrophilic and large molecules, as well as enzymatic and chemical degradation of the active substance in the gastrointestinal tract. There are various approaches used in the development of oral drug delivery systems. In particular, for the targeted delivery of drugs, it is proposed to use nano- and microcapsules with mucoadhesive properties. Among the polymers used for the synthesis of these microparticles, it is preferable to use pH-dependent, gelable biopolymers that change their structure depending on the acidity of the environment. Microcapsules obtained from compounds with the above properties are capable of protecting the active substance (or from the active substance) in the stomach environment and ensuring its release in the intestine. These properties are possessed by such polysaccharides as alginate, pectin, carrageenan, xylan, etc. The listed biopolymers are non-toxic, biocompatible, and biodegradable, which makes microparticles containing these polysaccharides promising as oral drug delivery systems. To impart mucoadhesive properties to nanoparticles, complexes of the listed polymers with chitosan are used. In this research, pectin, a polysaccharide formed mainly by residues of galacturonic acid, was used as a structural polymer. The concentrations of substances in the initial solutions were selected that were optimal for the synthesis of microcapsules. The main parameters for evaluating the resulting microparticles were the size of the capsules (less than 1 μm for oral inclusion), the zeta-potential, showing the tendency of the microparticles to stick together, and the completeness of the binding of the microparticles to chitosan. It was found that the optimal solutions for the synthesis of microparticles are: 15.7 ml of a solution of pectin 0.093% by weight, 3.3 ml of a solution of chitosan 0.07% by weight and 1.0 ml of a solution of CaCl2 20 mM. The diameter of the microparticles obtained by this method was 700-800 nm, and the value of their zetta-potential, equal to - (34 ± 3) mV, does not cross the particle adhesion threshold. It was also found that the synthesis of microparticles at these concentrations of calcium chloride provides the most complete binding of chitosan to their surface, which increases the mucoadhesive properties of microparticles."

An overview of Natural Superdisintegrants

2021 ◽  
pp. 113-124
Author(s):  
Shushank Sharma
Keyword(s):  
Gastrointestinal Tract ◽  
Aqueous Media ◽  
Chemical Properties ◽  
Cost Effective ◽  
Oral Route ◽  
Drug Formulation ◽  
Release Time ◽  
Disintegration Time ◽  
Physico Chemical ◽  
Set Up

The oral route is the most convenient route of administration for various drugs. It is viewed as the most convenient, most secure, and economical route for patients. Fast disintegrating tablets are popular these days as they disintegrate in the mouth within a few seconds without the use of water. The burdens of regularly used medications in pediatric and geriatric patients have been overwhelmed by quick-dissolving tablets. Natural superdisintegrants have been used for fast-dissolving tablets because they are biodegradable, chemically inert, non-harmful, more affordable, and generally accessible. Natural polymer improves the properties of the tablet as it is commonly used as diluents and binders. Natural super disintegrants decrease the release time and give healthful results to the patients. Most polymers are obtained from nature, they are cost-effective, non-toxic, and non-irritants. Disintegration is the most important step for releasing the drug from the tablet matrix to decrease the disintegration time. In this, drug and polymers come in contact with water, it swells, hydrate, and react chemically to release the drug in the mouth and gastrointestinal tract. Superdisintegrants are those substances that encourage the quick breaking down with a lesser amount contrasted with disintegrants. The quick disintegrants tablets are set up by utilizing suitable polymers which rely on the Physico-chemical properties of drugs and excipients, for example, drug and polymer compatibility, hardness and thickness of tablet, nature of drug and excipients, PH of drug and release parameters of drug formulation. Superdisintegrants are the vehicles added to tablet formulation to advance the breaking of tablets and capsules into small microparticles in aqueous media resulting in to increase in the surface area and promote quick drug release. The disintegrants have a significant capacity to oppose the efficacy of tablet binders and compression forces to form the tablet. Commonly there are three methods to incorporate disintegrants into the tablet: A. Inner addition, B. External expansion, C. Internal, and external addition. Most of the regularly based tablets are those expected to be swallow, disintegrate and release medicaments in the gastrointestinal tract but over a while tablets are manufactured to deliver medicaments in the mouth and gastrointestinal tract within few seconds of swallowing. It has been demonstrated that characteristic polymers are more effective than synthetic polymers. Some research is going to develop safe and effective medication with super disintegrating agents that can be dissolved rapidly to treat the disease.

ENTEROVIRUSES

PEDIATRICS ◽  
1958 ◽  
Vol 21 (6) ◽  
pp. 873-874
Author(s):  
HEINZ F. EICHENWALD
Keyword(s):  
Tissue Culture ◽  
Gastrointestinal Tract ◽  
Intestinal Tract ◽  
Enteric Viruses ◽  
Human Gastrointestinal Tract ◽  
New Family

A NUMBER of years ago, investigations utilizing monkeys resulted in the recovery of three types of poliomyelitis viruses from the human gastrointestinal tract. More recently, the use of infant mice led to the discovery of an entirely new family of enteric viruses, the Coxsackie agents, which, on the basis of histopathologic reactions in mice, are divisable into two subgroups: A, with 19 serologically distinct members; and B, with 5. A further advance in methodology, the use of simplified methods of tissue culture, resulted in the isolation of a third family of viruses from the intestinal tract, named, by general agreement, the enteric cytopathogenic human orphan (ECHO) group.

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