The Antiviral Action of Polyhexamethylene Guanidine Derivatives

Although the PHMG （polyhexamethylene guanidine） and other oligomer guanidines are known as highly efficient biocides against a broad spectrum of microorganisms and eukaryotic cells, the cell protection by PHMG derivatives has been established firstly in this study. The antiviral protection was also exhibited after 15 min pretreatment of different cell cultures with low-concentration of PHMG salts. Monolayers of the continuous bovine tracheal cells culture （TCC） and primary culture of chicken embryo fibroblasts （FCE） were treated with aqueous solutions of PHMG chloride salts or PHMG succinate. The molecules of PHMG polycation adhered to the plasma membrane of the cells tested as they were treated with PHMG for 15-30 min. The viral material was added to the cell cultures after the wash-out carried out twice to rid of unbound PHMG. The viruses of Equine herpesvirus type 1, Rhinotracheitis infectious bovine and Equine infectious anemia virus were used. The protective effect from the cytopathic action of herpes and retroviruses was exhibited after 15 min pretreatment of cell monolayer with PHMG chloride at the TCC concentrations of 10^-3 - 10^-2% and FCE concentrations of 10^-5 - 10^-4%. The unique antiviral properties of PHMG salts represented in our research had never been shown before.

Linkages of volatile fatty acids and polyhexamethylene guanidine stress during sludge fermentation:Metagenomic insights of microbial metabolic traits and adaptation

The massive use of polyhexamethylene guanidine(PHMG),as a typical bactericidal agent,raised environmental concerns to the public.This work comprehensively revealed the hormesis effects of PHMG occurred in waste activated sludge(WAS)on the generation of volatile fatty acids(VFAs)during anaerobic fermentation.The low level of PHMG(100 mg/g TSS)significantly promoted the VFAs generation(1283 mg COD/L,compared with 337 mg COD/L in the control)via synchronously facilitating the solubilization,hydrolysis,and acidification steps but inhibiting methanogenesis.Metagenomic analysis showed that the functional anaerobe(i.e.,Bacteroides,Macellibacteroide and Parabacteroide)and corresponding genetic expressions responsible for extracellular hydrolysis(i.e.,clp P),membrane transport(i.e.,ffh and gsp F),intracellular substrates metabolism(i.e.,ald and paa F)and VFAs biosynthesis(i.e.,ACACA and FASN)were enhanced in the optimal presence of PHMG.Moreover,the anaerobic species could respond and adapt to low PHMG stimuli via quorum sensing(i.e.,cqs A,rpf C and rpf G),and thus maintain the high microbial metabolic activities.However,they were unable to tolerate the toxicity of excessive PHMG,resulting in the extremely low VFAs production.This work enlightened the effects of emerging pollutants on WAS fermentation at the genetic levels,and provided guidance on the WAS treatment and resource recovery.