RESUMEN
Sequence variability in surface-antigenic sites of pathogenic proteins is an important obstacle in vaccine development. Over 200 distinct genomic sequences have been identified for human papillomavirus (HPV), of which more than 18 are associated with cervical cancer. Here, based on the high structural similarity of L1 surface loops within a group of phylogenetically close HPV types, we design a triple-type chimera of HPV33/58/52 using loop swapping. The chimeric VLPs elicit neutralization titers comparable with a mix of the three wild-type VLPs both in mice and non-human primates. This engineered region of the chimeric protein recapitulates the conformational contours of the antigenic surfaces of the parental-type proteins, offering a basis for this high immunity. Our stratagem is equally successful in developing other triplet-type chimeras (HPV16/35/31, HPV56/66/53, HPV39/68/70, HPV18/45/59), paving the way for the development of an improved HPV prophylactic vaccine against all carcinogenic HPV strains. This technique may also be extrapolated to other microbes.
Asunto(s)
Diseño de Fármacos , Papillomaviridae/inmunología , Infecciones por Papillomavirus/prevención & control , Vacunas contra Papillomavirus/inmunología , Neoplasias del Cuello Uterino/prevención & control , Animales , Anticuerpos Antivirales/genética , Anticuerpos Antivirales/inmunología , Proteínas de la Cápside/genética , Proteínas de la Cápside/inmunología , Evaluación Preclínica de Medicamentos , Epítopos/genética , Epítopos/inmunología , Femenino , Ingeniería Genética/métodos , Inmunogenicidad Vacunal , Macaca fascicularis , Masculino , Ratones , Ratones Endogámicos BALB C , Modelos Animales , Pruebas de Neutralización , Proteínas Oncogénicas Virales/genética , Proteínas Oncogénicas Virales/inmunología , Papillomaviridae/genética , Infecciones por Papillomavirus/inmunología , Infecciones por Papillomavirus/virología , Vacunas contra Papillomavirus/genética , Filogenia , Organismos Libres de Patógenos Específicos , Neoplasias del Cuello Uterino/inmunología , Neoplasias del Cuello Uterino/virologíaRESUMEN
Nanomaterial pollution and the spread of antibiotic resistance genes (ARGs) are global public health and environmental concerns. Whether nanomaterials could aid the transfer of ARGs released from dead bacteria into live bacteria to cause spread of ARGs is still unknown. Here, we demonstrated that nano-Al2O3 could significantly promote plasmid-mediated ARGs transformation into Gram-negative Escherichia coli strains and into Gram-positive Staphylococcus aureus; however, bulk Al2O3 did not have this effect. Under suitable conditions, 7.4 × 10(6) transformants of E. coli and 2.9 × 10(5) transformants of S. aureus were obtained from 100 ng of a pBR322-based plasmid when bacteria were treated with nano-Al2O3. Nanoparticles concentrations, plasmid concentrations, bacterial concentrations, interaction time between the nanomaterial and bacterial cells and the vortexing time affected the transformation efficiency. We also explored the mechanisms underlying this phenomenon. Using fluorescence in situ hybridization and scanning electron microscopy, we found that nano-Al2O3 damaged the cell membrane to produce pores, through which plasmid could enter bacterial cells. Results from reactive oxygen species (ROS) assays, genome-wide expression microarray profiling and quantitative real-time polymerase chain reactions suggested that intracellular ROS damaged the cell membrane, and that an SOS response promoted plasmid transformation. Our results indicated the environmental and health risk resulting from nanomaterials helping sensitive bacteria to obtain antibiotic resistance.
Asunto(s)
Óxido de Aluminio/toxicidad , Farmacorresistencia Bacteriana/genética , Escherichia coli/efectos de los fármacos , Genes Bacterianos , Nanoestructuras/toxicidad , Staphylococcus aureus/efectos de los fármacos , Óxido de Aluminio/química , Escherichia coli/genética , Transferencia de Gen Horizontal , Hibridación Fluorescente in Situ , Nanoestructuras/química , Plásmidos/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Staphylococcus aureus/genéticaRESUMEN
A rapid, sensitive and accurate method has been developed for the determination of seventeen 2, 3, 7, 8-substituted congeners of polychlorinated dibenzo-p-dioxins and dibenzo-furans (PCDD/Fs) in sediment using isotope dilution high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS). Dibenzo-p-dioxins and dibenzo-furans were extracted from samples by accelerated solvent extraction (ASE) and then purified by fluid management systems (FMS) with silica column, alumina column and carbon column. Confirmation and quantitative analysis at pg/g level of PCDD/Fs were performed by HRGC/HRMS using voltage selective ion record (VSIR) mode. Recoveries of fifteen isotopically labeled compound solutions (LCS) and the precision and recovery standards (PAR) were found to be in the range of 49.8% -85.3% and 93.2% - 113.8%, respectively. The detection limits of the method for both 2, 3, 7, 8-tetrachloro-dibenzo-furan (TCDF) and 2, 3, 7, 8-tetrachloro-dibenzo-p-dioxin (TCDD) were determined to be 0.1 pg/g. This method not only meets the requirements of international standards, but also shortens analysis time from 2 weeks to 2 days.