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Biomedical subjects

S M Goyal

Publications and source records attributed to S M Goyal.

At least 109 records · Page 6Linked to original sources
PubMed1980

Simple method for the concentration of influenza virus from allantoic fluid on microporous filters.

Membrane filter adsorption-elution is an efficient method for concentration and partial purification of several types of viruses from various aqueous solutions. For efficient virus adsorption to negatively charged filters, the sample is adjusted to pH 3.5 and trivalent salts are added before filtration. Since influenza virus is sensitive to extremes in pH, it cannot be concentrated by ordinary filters. Zeta Plus filters, which have a net positive charge of up to 5 or 6, were evaluated for the concentration of influenza virus from infectious allantoic fluids. Influenza virus efficiently adsorbed to Zeta Plus filters at pH 6, and addition of salts was not necessary. Adsorbed virus was eluted in a small volume of 2% bovine serum albumin plus 1 M NaCl at pH 10. By this procedure, viruses in 100 ml of allantoic fluid were concentrated to a final volume of 8 ml, with an average recovery efficiency of 71.0%.

Adsorption↗
PubMed1980

Movement of endotoxin through soil columns.

Land treatment of wastewater is an attractive alternative to conventional sewage treatment systems and is gaining widespread acceptance. Although land application systems prevent surface water pollution and augment the available water supplies, the potential dangers to human health should be evaluated. Since sewage may contain high amounts of bacterial endotoxin, the removal of endotoxin from sewage by percolation through soil was investigated. It was found that 90 to 99% of the endotoxin was removed after travel of sewage through 100 to 250 cm of loamy sand soil. When distilled water was allowed to infiltrate into the soil to simulate rainfall, the endotoxin was mobilized and moved in a concentrated band through the soil column. On testing samples from actual land treatment sites, as much as 480 ng of endotoxin per milliliter was found in some groundwater samples. The presence of endotoxin in potable water is known to be a potential problem under some circumstances, but the importance of endotoxin in water supplies has not been fully assessed. Therefore, the design, operation, and management of land application systems should take into account the fate of endotoxin in groundwater beneath the sites.

Endotoxins↗
PubMed1980

Relationships between environmental factors, bacterial indicators, and the occurrence of enteric viruses in estuarine sediments.

Current standards for evaluation of the public health safety of recreational and shellfish-harvesting waters are based upon bacteriological analysis, but do not include an evaluation of the number of viruses. The objective of this study was to determine the occurrence of enteric viruses in estuarine sediments and to find a relationship, if any, between the presence of viruses in seawater or sediment or both and various biological and physicochemical characteristics of the environment. Viruses were found in greater numbers in sediment than in overlying seawater on a volume basis. Several types of enteroviruses were isolated: coxsackievirus types A16, B1, and B5, echovirus type 1, and poliovirus type 2. On several occasions, viruses were isolated from sediments when overlying seawaters met bacteriological water quality standards for recreational use. Statistical analysis of the relationship between viruses in seawater or in sediment and other variables measured yielded only one significant association: the number of viruses in sediment was found to be positively correlated with the number of fecal coliforms in sediment. No other physical, chemical, or biological characteristic of seawater or sediment that was measured showed statistically significant association with viral numbers. No correlation was found between bacterial indicators and virus in the overlying waters. The data indicated that evaluation of the presence of bacteria and viruses in sediment may provide additional insight into long-term water quality conditions and that indicator bacteria in water are not reflective of the concentration of enteric viruses in marine waters.

Clostridium↗
PubMed1980

Capture of latex beads, bacteria, endotoxin, and viruses by charge-modified filters.

This report demonstrates how electropositive filters can be used to enhance the removal of microorganisms and other negatively charged particles from water. It was shown that electropositive depth filters were capable of adsorbing viruses and endotoxins many times smaller than the average pore size of the filter. Electronegative filters of similar porosity or electropositive filters that had been treated to destroy the positive charge were almost ineffective under similar conditions for the removal of viruses and small latex spheres. The results of this study indicate that electropositive filters are highly effective in the removal of a wide range of contaminants over a wide range of pH values and ionic conditions.

Endotoxins↗
PubMed1980

Simple method for concentration of bacteria from large volumes of tap water.

Membrane adsorption-elution techniques have made it possible to concentrate and detect small numbers of viruses in large volumes of water and wastewater, but no such methods are available for quantitative recovery of bacteria. A number of waterborne disease outbreaks of "unknown etiology" in the United States are suspected to have been caused by pathogens present in numbers too small to be detected by currently available methodology. The present study reports on the use of positively charged depth filters for the concentration and detection of bacteria in large volumes of tap water. In this method, dechlorinated tap water was passed, under positive pressure, through positively charged filter media (Zetaplus, 05S). More than 90% of seeded bacteria adsorbed to these filters at ambient pH levels. Adsorbed bacteria were eluted by passing a small volume of Trypticase soy broth in the direction opposite of the influent flow. By this method, Escherichia coli and Salmonella serovar B organisms in 20 liters of tap water were concentrated in a final volume of 50 ml, with an average recovery efficiency of greater than or equal to 30%.

Adsorption↗
PubMed1979

Human enteroviruses in oysters and their overlying waters.

The presence of enteroviruses in oysters and oyster-harvesting waters of the Texas Gulf coast was monitored over a period of 10 months. Viruses were detected in water and oyster samples obtained from areas both open and closed to shellfish harvesting. Viruses were detected periodically in waters that met current bacteriological standards for shellfish harvesting. No significant statistical relationship was demonstrated between virus concentration in oysters and the bacteriological and physiochemical quality of water and shellfish. Viruses in water were, however, moderately correlated with total coliforms in water and oysters and with fecal coliforms in oysters. Total coliforms in water were realted to total coliforms in sediment were related only to total coliforms in sediment. Among the physiochemical characteristics of water, turbidity was related statistically to the organic matter content of water and to fecal coliforms in water. There was a marked effect of rainfall on the bacteriological quality of water. Of a total of 44 water samples, 26 yielded virus in concentrations from 4 to 167 plaque-forming units per 100-gallon (ca. 378.5-liter) sample. Of a total of 40 pools of 10 to 12 oysters each, virus was found in 14 pools at a concentration of 6 to 224 plaque-forming units per 100 g of oyster meat. On five occasions, virus was found in water samples when no virus could be detected in oysters harvested from the same sites. This study indicates that current bacteriological standards for determining the safety of shellfish and shellfish-growing waters do no reflect the occurrence of enteroviruses.

Animals↗
PubMed1979

Comparative adsorption of human enteroviruses, simian rotavirus, and selected bacteriophages to soils.

Virus adsorption to soils is considered to be the most important factor in removing viruses after land treatment of wastewater. Most of the studies on virus adsorption to soils have utilized poliovirus as the model system. In the present study, comparative adsorption of a number of different types and strains of human enteroviruses and bacteriophages to nine different soil types was studied. Under the experimental conditions of this study, greater than 90% of all viruses adsorbed to a sandy loam soil except echovirus types 1, 12, and 29 and a simian rotavirus (SA-11), which adsorbed to a considerably lower degree. A great deal of variability was observed between adsorption of different strains of echovirus type 1, indicating that viral adsorption to soils is highly strain dependent. Of the five phages studied, f2 and phi X174 adsorbed the least. In addition to being dependent on type and strain of virus, adsorption was found to be influenced also by type of soil. Thus, soils having a saturated pH of less than 5 were generally good adsorbers. From these results, it appears that no one enterovirus or coliphage can be used as the sole model for determining the adsorptive behavior of viruses to soils and that no single soil can be used as the model for determining viral adsorptive capacity of all soil types.

Adsorption↗
PubMed1979

Failure of indicator bacteria to reflect the occurrence of enteroviruses in marine waters.

The results of several studies conducted along the upper Texas Gulf coast, where a substantial amount of quantitative virological data were collected, are compared to bacteriological indicators and other environmental factors on a statistical basis. Variables common to all these studies were anlayzed by multivariate regression. Although multivariate analysis indicated that the number of viruses detected in water was related to rainfall, salinity, and total coliforms in the water, the amount of variation in the number of viruses accounted for by these factors was not large enough to make them good predictors. Enteroviruses were detected 43 per cent of the time in recreational waters considered acceptable as judged by coliform standards, and 44 per cent of the time when judged by fecal coliform standards. Enteroviruses were detected 35 per cent of the time in waters which met acceptable standards for shellfish-harvesting. Our failure to correlate the occurrence of enteroviruses in marine waters with indicator bacteria, and the frequent occurrence of enteroviruses in water which met current bacteriological standards, indicates that these standards do not reflect the occurrence of enteroviruses, and perhaps other human pathogenic viruses, in marine waters.

Animals↗
PubMed1978

Comparison between adsorption of poliovirus and rotavirus by aluminum hydroxide and activated sludge flocs.

Adsorption of poliovirus and rotavirus by aluminum hydroxide and activated sludge flocs was studied. Both aluminum hydroxide and activated sludge flocs adsorbed greater amounts of poliovirus than rotavirus. Aluminum hydroxide flocs reduced the titer of poliovirus in tap water by 3 log10, but they only reduced the titer of a simian rotovirus (SA-11) in tap water by 1 log10 or less and did not noticeably reduce the number of human rotavirus particles present in a dilute stool suspension. Activated sludge flocs reduced the titer of added poliovirus by 0.7 to 1.8 log10 and reduced the titer of SA-11 by 0.5 log10 or less. These studies indicate that a basic difference in the adsorptive behavior of enteroviruses and rotaviruses exists and that water and wastewater treatment processes that are highly effective in removal of enteroviruses may not be as effective in removing other viral groups such as rotaviruses.

Adsorption↗
PubMed1978

Concentration of enteroviruses from large volumes of tap water, treated sewage, and seawater.

Methods are described for the efficient concentration of an enterovirus from large volumes of tap water, sewage, and seawater. Virus in acidified water (pH 3.5) in the presence of aluminum chloride was adsorbed to a 10-inch (ca. 25.4 cm) fiberglass depth cartridge and a 10-inch pleated epoxy-fiberglass filter in a series at flow rates of up to 37.8 liters (10 gallons) per min. Adsorbed viruses were eluted from the filters with glycine buffer (pH 10.5 to 11.5), and the eluate was reconcentrated by using a combination of aluminum flocculation followed by hydroextraction. With this procedure, poliovirus in large volumes of tap water, seawater, and sewage could be concentrated with an average efficiency of 52, 53, and 50%, respectively. It was demonstrated that this method is capable of detecting surface solid-associated viruses originating from sewage treatment plants. No difference in virus recovery between laboratory batch studies and a set-up with acid-salt injection was found. This unified scheme for the concentration of viruses has many advantages over previously described systems. These include: high operating flow rates, low weight and small size, effectiveness with a variety of waters with widely varying qualities, and filters with a high resistance to clogging.

Enterovirus↗
PubMed1978

Concentration of poliovirus from tap water onto membrane filters with aluminum chloride at ambient pH levels.

A method is described for the concentration of an enterovirus from large volumes of tap water by addition of small amounts of aluminum chloride to enhance virus removal by membrane filters. Tap water treated with 2 X 10(-5) M aluminum chloride showed a slight decrease in pH (less than 0.5), a slight increase in turbidity, and enhanced removal of poliovirus by membrane filters. Virus was quantitatively recovered by treating the filters with a basic buffer, and this eluate was reconcentrated to a small volume by adsorption to aluminum hydroxide flocs. Using these procedures, virus from 1,000 liters of water was reduced to a final eluate of 20 to 80 ml with a mean recovery of 70%.

Adsorption↗
PubMed1978

A simple method for concentration of enteroviruses and rotaviruses from cell culture harvests using membrane filters.

Organic compounds in cell culture harvests known as membrane-coating components (MCC) prevent virus adsorption to membrane filters. Blending cell culture harvests with fluorocarbon removed the MCC and permitted adsorption of virus in acidified harvests to epoxy-fiberglass filters. Subsequent elution with high pH buffer resulted in recovery of greater than 90% of the virus with concentrations of up to 100-fold.

Enterovirus↗
PubMed1977

Concentration of enteroviruses from estuarine water.

Pleated cartridge filters readily adsorb viruses in estuarine water at low pH containing aluminum chloride. Adsorbed viruses are efficiently recovered by treating filters with glycine buffer at high pH. By using these procedures, it was possible to recover approximately 70% of the poliovirus added to 400 liters of estuarine water in 3 liters of filter eluate. Reconcentration of virus in the filter eluate in small volumes that are convenient for viral assays was more difficult. Reconcentration methods described previously for eluates from filters that process tap water or treated wastewater were inadequate when applied to eluates from filters used to process estuarine water containing large amounts of organic compounds. Two methods were found to permit efficient concentration of virus in filter eluates in small volumes. In both methods, virus in 3 liters of filter eluate was adsorbed to aluminum hydroxide flocs and then recovered in approximately 150 ml of buffered fetal calf serum. Additional reductions in volume were achieved by ultrafiltration or hydroextraction. By using these procedures 60 to 80% of the virus in 3 liters of filter eluate could be recovered in a final volume of 10 to 40 ml.

Adsorption↗
PubMed1977

Occurrence and distribution of bacterial indicators and pathogens in canal communities along the Texas coast.

Increased construction of residential canal communities along the southern coastline of the United States has led to a concern about their impact on water quality. Pollution of such dead-end canals is potentially hazardous because of their heavy usage for recreational activities. Coliforms, fecal coliforms, and salmonellae in the surface water and bottom sediments of six selected residential coastal canals were monitored over a period of 17 months. No statistically significant relationship was observed between the organism concentrations and temperature, pH, turbidity, and suspended solids content of water. An inverse relationship between the concentration of indicator organism and salinity of water was found, however, to occur at a 99.9% level of significance. All of the microorganisms studied were found to be present in greater numbers in sediments than in the overlying water, often by a factor of several logs. Heavy rainfall resulted in large increases in the number of organisms in both water and sediment samples. Our results indicate that bottom sediments in the shallow canal systems can act as reservoirs of enteric bacteria, which may be resuspended in response to various environmental factors and recreational activities.

Escherichia coli↗