An in-depth study of the continuous cell line designated BGM is described herein, and recommendations are made for standardizing cell culture and viral assay procedures. Based on data gathered from a survey of 58 laboratories using this cell line, a research plan was developed that included the study of growth media, sera, NaHCO3 levels, culture bottles, cell concentration, overlay media, agar, virus infection conditions, and cell-dissociating agents. Additionally, a comparative virus isolation study with BGM cells and nine other cell types was conducted with 37 sewage samples collected from nine different geographic areas. The results of the study indicated that the BGM cell line is superior for virus isolation when compared with the other cell types and that certain media and additives tend to increase BGM cell sensitivity to a specific group of viruses. A standardized procedure for cultivation of BGM cells is described which provides a more effective enterovirus assay system.
SynopsisThe thermal degradation in vacuum of a number of fluorine-containing polymers has been studied by using a weight loss technique. The relative thermal stabilities of the different polymers have been determined and where possible the overall activation energy and frequency factors for their breakdown. The methods of assessment of the weight loss results are discussed. The most stable of the polymers are those which are fully fluorinated.
A reduction in virus recovery efficiencies stemming from a change in the commercial processing of powdered beef extract was reversed by the addition of Celite analytical filter aid. Supplementing beef extract with this silicate is recommended as a modification to the organic flocculation procedure for second-step concentration in monitoring for waterborne viruses. Considerable differences in virus recovery were found among lots of beef extract and Celite preparations; this indicates that the performance of each lot of these substances should be checked before use.
Sewage treatment plant effluents were surveyed for viral contributions to gastroenteritis outbreaks in Puerto Rico. Of the 15 sewage treatment plants studied, all discharged their effluents upstream from water treatment plant intakes. No base-line data on the degree of viral challenge to these sewage treatment plants or the subsequent reduction of viruses before discharge existed. Enterovirus counts were generally much higher than those found in the continental United States. At four plants, viruses in the incoming sewage exceeded 100,000 PFU/liter, and one of these, a trickling filter plant, was discharging 24,000 PFU/liter to receiving waters. Virus identification showed that more than 80% of the enterovirus isolates were coxsackievirus B5. These overwhelming viral numbers pointed to defects in the sewage treatment processes. Without reasonable barriers to protect receiving waters, several of the downstream communities were using raw waters that posed extraordinary demands on the ability of their water treatment plants to supply virologically safe drinking water.
Six laboratories actively involved in water virology research participated in a methods evaluation study, conducted under the auspices of the American Society for Testing and Materials Committee on Viruses in the Aquatic Environment, Task Force on Drinking Water. Each participant was asked to examine the Viradel (virus adsorption-elution) method with cartridge-type Filterite filters for virus adsorption and organic flocculation and aluminum hydroxide-hydroextraction for reconcentration. Virus was adsorbed to filter media at pH 3.5 and eluted with either glycine buffer (pH 10.5) or beef extract-glycine (pHG 9.0). Considerable variation was noted in the quantity of virus recovered from four 100-liter samples of dechlorinated tapwater seeded with low (350 to 860 PFU) and high (1,837 to 4,689 PFU) doses of poliovirus type 1. To have a more uniform standard of comparison, all the test samples were reassayed in one laboratory, where titers were also determined for the virus seed. Test results of the Viradel-organic flocculation method indicated that the average percentage of virus recovery for low-input experiments was 66%, with a range of 8 to 20% in two laboratories, 49 to 63% in three laboratories, and 198% in one laboratory. For the high-input experiments, two laboratories reported recoveries of 6 to 12%, and four laboratories reported recoveries of 26 to 46%. For the Viradel aluminum hydroxide-hydroextraction procedure, two laboratories recovered 9 to 11%, whereas four obtained 17 to 34% for low-input experiments. For the high-input tests, two laboratories reported a recovery of 3 to 5%, and four recovered 11 to 18% of the seeded virus.(ABSTRACT TRUNCATED AT 250 WORDS)
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.