RESUMEN
Organophosphate esters (OPEs), extensively used as flame retardants, are widely detected in various regions and environments. The potential toxicity of OPEs has caused great concern in recent years. Based on the global distillation model, the Tien Shan glaciers, such as Urumqi Glacier No. 1, could be as a potential "sink" for OPEs. However, little is known about the concentration, distribution, potential sources, and ecological risks of OPEs in Tien Shan glaciers. In this study, fresh snow samples were collected at various altitudes on the Urumqi Glacier No. 1, eastern Tien Shan, China. The total concentrations of ten OPEs (Σ10OPEs) ranged from 116 to 152 ng/L. The most abundant OPE was tris-(2-chloroisopropyl) phosphate (TCIPP), contributing to 74 % of the total OPEs. Σ10OPEs, tri-n-butyl phosphate (TnBP), and TCIPP concentrations showed positive correlations with altitude, indicating the effect of cold condensation on OPEs deposition. Based on air mass back-trajectory analysis and principal component analysis, we found that emissions from both traffic and household products in indoor environment were the important sources, and OPEs on the Urumqi Glacier No. 1 might mainly originate from Europe. Our assessment also showed triphenyl phosphate (TPhP) posed a low ecological risk in snow. This is the first systematic study of OPEs on the Tien Shan glaciers.
RESUMEN
Acute toxicity and immunoprotection of Actinobacillus pleuropneumoniae (APP) ApxI toxin recombinant proteins (include crude inclusion bodies and refolded recombinant protein) were evaluated in mice, and compared with the natural ApxI extracted from culture supernatant of APP serotype 10. In the acute toxicity experiment, the three proteins were intraperitoneally injected into Kunming mice in a dose of 200microg per mouse. The body and organ weight, heamatological and biochemical indexes were examined at 24h, 7 days and 14 days post administration. There was no death after the intraperitoneal administration of the three proteins, and no significant change was found in the body weight, organ indexes, heamatological and biochemical indexes. To study their immunoprotection, the three proteins were emulsified with Freund's adjuvant respectively and vaccinated the mice twice with a 2-week of interval. Two weeks after the second vaccination, the mice were challenged intraperitoneally with a lethal dose of APP serotype 10 (1.09 x 10(8) cfu), and serums were examined by an ApxI-specific ELISA. The results revealed that the recombinant protein had a good immunogenicity and could induce protection immune reaction.
Asunto(s)
Actinobacillus pleuropneumoniae/inmunología , Proteínas Bacterianas/inmunología , Vacunas Bacterianas/inmunología , Proteínas Hemolisinas/inmunología , Proteínas Recombinantes/inmunología , Infecciones por Actinobacillus/prevención & control , Actinobacillus pleuropneumoniae/genética , Actinobacillus pleuropneumoniae/metabolismo , Animales , Proteínas Bacterianas/genética , Vacunas Bacterianas/genética , Clonación Molecular , Escherichia coli/genética , Escherichia coli/metabolismo , Femenino , Proteínas Hemolisinas/genética , Inmunización , Masculino , Ratones , Distribución Aleatoria , Proteínas Recombinantes/genética , Pruebas de Toxicidad AgudaRESUMEN
Apx IV, a forth RTX toxin indentified in Actionbacillus pleuropneumoniae recently, is expressed by all A. pleuropneumoniae regardless the serotypes and inducible only in vivo toxin, so it is the optimal to develop species-specific and differentiated diagnostic assay. Here the 2445bp DNA fragment of apxIVA gene of A. pleuroneumoniae was amplified and fused in-frame to the downstream of the T7 promoter and 6 His Tag of the prokaryotic expression vector pET-28b. The construct was transformed into E. coli BL21(DE3). After induction by 1.0 mol/L IPTG, a recombinant protein about 90 kD in size, designed as ApxIVAN, was detected, which was present as inclusion bodies and reacted specifically with swine antisera to the APP-serotype-1 by dot-blot. An indirect ELISA (ApxIVA-ELISA) was developed using purified recombinant ApxIVAN from the inclusion bodies as described previously, which had excellent specificity to A. pleuroneunoniae. Using the ApxIVA-ELISA, the ApxIV antibodies were not detected in the inactivated APP bacterins vaccinated pigs, but were detected in A. pleuropneumoniae serotype 1, 2 and 7 infected pigs and mice. These results suggested that ApxIVA-ELISA can be used not only to detect all serotypes of APP, but also to differentiate the naturally infected and inactivated vaccine immunized pigs.
