Mutual impacts and interactions of antibiotic resistance genes, microcystin synthetase genes, graphene oxide, and Microcystis aeruginosa in synthetic wastewater

Abstract

The physiological impacts and interactions of ARGs abundance, microcystin synthetase genes expression, GO, and M. aeruginosa in synthetic wastewater were investigated. The results demonstrated that the absolute abundance of sul1, sul2, tetW, and tetM in synthetic wastewater dramatically increased to 365.2%, 427.1%, 375.2%, and 231.7%, respectively, when the GO concentration was 0.01 mg/L. Even more interesting is that the sum gene copy numbers of mcyA-J also increased to 243.2%. The appearance of GO made the significant correlation exist between ARGs abundance and mcyA-J expression. Furthermore, M. aeruginosa displayed better photosynthetic performance and more MCs production at 0.01 mg/L GO. There were 65 pairs of positive correlations between the intracellular differential metabolites of M. aeruginosa and the abundance of sul1, sul2, tetM, and tetW with various GO concentrations. The GO will impact the metabolites and metabolic pathway in M. aeruginosa. The metabolic changes impacted the ARGs, microcystin synthetase genes, and physiological characters in algal cells. Furthermore, there were complex correlations among sul1, sul2, tetM, tetW, mcyA-J, MCs, photosynthetic performance parameters, and ROS. The different concentration of GO will aggravate the hazards of M. aeruginosa by promoting the expression of mcyA-J, producing more MCs, simultaneously, it may cause the spread of ARGs.

Low Levels of Contaminants Stimulate Harmful Algal Organisms and Enrich Their Toxins

“…This screening revealed eight additional papers. Thus, a total of 39 papers are included in this review, most of which include multifactorial experiments, such as different contaminants, strains, or additional experimental treatments other than contaminants. − …”

“…This review revealed numerous studies showing that various chemicals often induce hormesis in HAB-forming and toxin-producing cyanobacteria (blue-green algae), in particular, in different strains of Microcystis wesenbergii , and M . aeruginosa . ,,− ,,,− ,− , However, hormetic responses were also revealed in the neurotoxin-producing Anabaena flos-aquae and the bloom-forming haptophyte Prymnesium parvum , which produces the phycotoxin prymnesi . Such hormetic responses were further identified in Synechocystis sp., which may also contribute to bloom formation .…”

“…Hormetic responses of HAB-forming and toxin-producing cyanobacteria are induced by many chemicals, such as arsenate, , environmental estrogens, chlorinated organophosphorus flame retardants (Cl-OPFRs), halogenated organic compounds, heavy metals, hydrogen peroxide (algaecide), and the principal compound of yellow dye luteolin and other allelopathic chemicals/algaecides. ,− They were also induced by various antibiotics, ,,− ,,− nanomaterials, polycyclic aromatic hydrocarbons, rare earths, , and several pesticides and disinfectants. ,,,− Hence, hormetic responses represent a universal phenomenon across chemically diverse contaminants. The studies providing such evidence commonly apply environmentally relevant concentrations, demonstrating that realistic concentrations widely enhance harmful algae and the production of microcystins.…”

Contaminants of emerging concern and aquatic organisms: the need to consider hormetic responses in effect evaluations

“…A further survey of the literature for the purpose of this study revealed ample evidence suggestive of hormesis for numerous aquatic organisms and various pollutants and emerging contaminants in dozens of publications, of which only a few selected examples are cited here (older examples can also be traced in the therein references). These examples include a plethora of species, such as of algae (microphytes) [38][39][40][41][42][43][44][45][46][47][48][49] , aquatic flowering plants [50] , organism-attached biofilms [51] , crustaceans [52][53][54][55][56][57] , cyanobacteria [49,[58][59][60][61] , fishes [62][63][64][65][66][67][68][69] , macrophytes [70][71][72][73][74][75] , marine polychaete [76] , mollusks (e.g., clams and mussels) [77,78] , periphyton [79] , phytoplankton [80] , sea anemones [81,82] , and snails [83] . Responses suggestive of hormesis were found for molecular (molecules...…”

“…Responses suggestive of hormesis were found for molecular (molecules involved in oxidative stress), cellular (e.g., growth and density), and whole-organism (e.g., growth and body mass) endpoints, as well as endpoints suggesting potential sub-NOAEL effects on organismic interactions, such as via altered feeding activity [83] . Such responses were induced by chemicals such as antibiotics/antifungals [38,39,42,45,50,51,67,70,71,75] , steroid hormones [41,83] , and other human drugs [63,69] , bisphenol A and its substitutes [66] , chemical leached from disposed light sticks [55] , electroplating processemitted particulate matter [40] , effluents from textile-dyeing wastewater treatment plants [46] , fullerene crystals (nC 60 ) [57] , metals and ionic liquids [62,77,81,82] , micro/nanoplastics and their leachates [43,44,47,53,60,64,80,84] , engineered nanomaterials [58,59,61,65] , pesticides [48,49,52,56,[72][73][74]79,84] , phthalic acid esters ...…”