Effects of Aqueous Film-Forming Foams (AFFFs) on Trichloroethene (TCE) Dechlorination by a Dehalococcoides mccartyi-Containing Microbial Community

The application of aqueous film-forming foams (AFFFs) to extinguish chlorinated solvent-fueled fires has led to the co-contamination of poly- and perfluoroalkyl substances (PFASs) and trichloroethene (TCE) in groundwater and soil. Although reductive dechlorination of TCE by Dehalococcoides mccartyi is a frequently used remediation strategy, the effects of AFFF and PFASs on TCE dechlorination are not well-understood. Various AFFF formulations, PFASs, and ethylene glycols were amended to the growth medium of a D. mccartyi-containing enrichment culture to determine the impact on dechlorination, fermentation, and methanogenesis. The community was capable of fermenting organics (e.g., diethylene glycol butyl ether) in all AFFF formulations to hydrogen and acetate, but the product concentrations varied significantly according to formulation. TCE was dechlorinated in the presence of an AFFF formulation manufactured by 3M but was not dechlorinated in the presence of formulations from two other manufacturers. Experiments amended with AFFF-derived PFASs and perfluoroalkyl acids (PFAAs) indicated that dechlorination could be inhibited by PFASs but that the inhibition depends on surfactant concentration and structure. This study revealed that the fermentable components of AFFF can stimulate TCE dechlorination, while some of the fluorinated compounds in certain AFFF formulations can inhibit dechlorination

Comparative analysis of the immunogenicity of monovalent and multivalent rotavirus immunogens

<div><p>The strategies for developing rotavirus (RV) vaccines have always been controversial. At present, both the monovalent RV vaccine and the multivalent RV vaccine have displayed excellent safety and efficacy against RV infection and shown cross-reactive immunity, which laid the question whether the multivalent RV vaccine could be replaced by the monovalent RV vaccine. In this study, we focused on comparing the immunogenicity (serum neutralization activity and protection against homotypic and heterotypic RVs’ challenge) of individual standard RV strains (monovalent RV immunogens) and different combinations of them (multivalent RV immunogens). In result, RV immunogens showed general immunogenicity and heterotypic reaction but the multivalent RV immunogens exhibited greater serum neutralization activity and stronger heterotypic reaction than the monovalent RV immunogens (P<0.05). As to the protection, the multivalent RV immunogens also revealed more rapid and stronger protection against homotypic and heterotypic RVs’ challenge than the monovalent RV immunogens. The results demonstrated that both the monovalent and multivalent RV immunogens exhibited high immunogenicity, but the monovalent RV immunogens could not provide enough neutralization antibodies to protect MA104 cells against the infection with heterotypic RV strains and timely protection against homotypic and heterotypic RVs, so the multivalent RV vaccine could not be replaced by the monovalent RV vaccine.</p></div

Neutralization test results of every group.

<p>The neutralization titers of each serum sample in every group were detected by neutralization tests against all the three RV immunogens Wa (G1P[8] genotype), SA11 (G3P[1] genotype) and Gottfried (G4P[6] genotype) after every dose. Data were expressed as GM*GSE^±tα/2,ν. GM stood for Geometric Mean. GSE stood for Geometric Standard Error. In this study, α = 0.05 and ν = n-1 = 8–1 = 7, so the corresponding t value was able to be found according to the tables for statistical distributions (t-distribution). The heights of columns were based on the GM of each test and the error bar stood for the 95% confidence interval.</p

Synergistic effect in bivalent RV immunogens.

<p>The heterotypic reactions induced by bivalent RV immunogens were stronger than those induced by monovalent RV immunogens which were the components of bivalent RV immunogens (P<0.05). And the heterotypic reactions induced by bivalent RV immunogens were even at the same level as the homotypic reactions induced by the homotypic monovalent RV immunogens (P>0.05).</p

Groups, sample sizes, infection routes and infection doses in animal experiments.

<p>Groups, sample sizes, infection routes and infection doses in animal experiments.</p

Comparative analysis of heterotypic reactions between monovalent and bivalent RV immunogens.

<p>The heterotypic reactions were evaluated by comparing the neutralization titers against heterotypic RV strains that were not contained in monovalent and bivalent RV immunogens 15 days after 2nd and 3rd dose.</p

Infectious titers of different genotypes RV immunogens.

<p>Infectious titers of different genotypes RV immunogens.</p

Percentage of RV fecal shedding in suckling mice after RV strains challenge.

<p>Suckling mice have required passive immunity from their mother mice. Fecal samples were collected from suckling mice, processed and RV-antigen detected by ELISA test after RV strains challenge. Virus infection rates were expressed as percentage of RV shedding.</p

Comparative analysis of homotypic reactions between monovalent, bivalent and trivalent RV immunogens.

<p>The homotypic reactions were evaluated by comparing the neutralization titers against homootypic RV strains that were contained in monovalent, bivalent and trivalent RV immunogens 15 days after 2nd and 3rd dose.</p