RESUMO
Microplastics pollution in marine environments is concerning. Microplastics persist and accumulate in various sections of the ocean where they present opportunity for micropollutant accumulation and microbial colonisation. Even though biofilm formation on plastics was first reported in the 1970's, it is only in recent years were plastic associated biofilms have gained research attention. Plastic surfaces pose a problem as they are a niche ready for colonisation by diverse biofilm assemblages, composed of specific bacterial communities and putative pathogens prone to acquiring ARGs and resistance in the biofilm. However, the nature of antibiotic resistance on aquatic plastic debris is not yet fully understood and remains a concern. Given the inevitable increase of plastic production and waste generation, microplastics released into the environment may prove to be problematic. This review explores microplastic waste in the ocean and possible concerns that may arise from the presence of microplastics in conjunction with favourable conditions for the development and dispersal of antibiotic resistance in the ocean and food web.
Assuntos
Microplásticos , Poluentes Químicos da Água , Bactérias/genética , Monitoramento Ambiental , Poluição Ambiental , Oceanos e Mares , Plásticos , Poluentes Químicos da Água/análiseRESUMO
The genetically modified (GM) maize event MON810 has been inserted with a processed version of the transgene, cry1Ab, derived from the soil bacterium Bacillus thuringiensis (Bt) to express proteins with insecticidal properties. Such proteins may introduce new allergens and also act as adjuvants that promote allergic responses. While focus has been on safe consumption and hence the oral exposure to GM food and feed, little is known regarding inhalation of pollen and desiccated airborne plant material from GM crops. The aim of this study was to investigate whether plant material from the Cry1Ab-expressing maize variety MON810, or trypsin-activated Cry1Ab (trypCry1Ab) protein produced in recombinant bacteria, may act as adjuvants against the allergen ovalbumin (OVA) in a mouse model of airway allergy. A clear proallergic adjuvant effect of the mucosal adjuvant cholera toxin (CT) was demonstrated, determined as increased specific IgE, eosinophils and Th2 cytokines in MLN cell supernates, while no elevation in OVA-specific antibodies or cytokine release from MLN cells after stimulation with OVA were observed in mice receiving Cry1Ab-containing plant materials or the trypCry1Ab protein. Our data suggest that Cry1Ab proteins had no detectable systemic adjuvant effect in mice after airway exposure. Further experiments with purified plant proteins, as well as long-term exposures needs be conducted to further evaluate exposures experienced in real-life situations.
Assuntos
Adjuvantes Imunológicos/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/farmacologia , Endotoxinas/genética , Endotoxinas/farmacologia , Proteínas Hemolisinas/genética , Proteínas Hemolisinas/farmacologia , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Recombinantes de Fusão/farmacologia , Adjuvantes Imunológicos/genética , Alérgenos/imunologia , Animais , Anticorpos/sangue , Bacillus thuringiensis/genética , Toxinas de Bacillus thuringiensis , Líquido da Lavagem Broncoalveolar/citologia , Toxina da Cólera/imunologia , Citocinas/metabolismo , Eosinófilos/imunologia , Feminino , Imunoglobulina E/biossíntese , Imunoglobulina E/imunologia , Inseticidas/farmacologia , Contagem de Linfócitos , Linfócitos/imunologia , Macrófagos/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Mutagênese Insercional/genética , Neutrófilos/imunologia , Ovalbumina/imunologia , Proteínas de Plantas/genética , Distribuição Aleatória , Proteínas Recombinantes de Fusão/genética , Células Th2/imunologia , Tripsina/metabolismo , Zea mays/genética , Zea mays/metabolismoRESUMO
OBJECTIVES: To determine the genetic composition of the first VanA-type plasmid (pIP816) reported, which was isolated from a clinical Enterococcus faecium (BM4147) strain in France in 1986, and to reveal the genetic units responsible for the dissemination of the vanA gene cluster by comparisons with current, published and additionally generated vanA-spanning plasmid sequences obtained from a heterogeneous E. faecium strain collection (n = 28). METHODS: Plasmid sequences were produced by shotgun sequencing using ABI dye chemistry and primer walking, and were subsequently annotated. Comparative sequence analysis of the vanA region was done with published plasmids, with a partial vanA plasmid (pVEF4) reported here and to >140 kb of sequence obtained from a collection of vanA-harbouring plasmid fragments. RESULTS: Bioinformatic analyses revealed that pIP816 from 1986 and contemporary vanA plasmids shared a conserved genetic fragment of 25 kb, spanning the 10.85 kb vanA cluster encoded by Tn1546, and that the larger unit is present in both clinical and animal complexes of E. faecium. A new group II intron in pVEF4 was characterized. CONCLUSIONS: Comparative DNA analyses suggest that Tn1546 disseminates in and between clonal complexes of E. faecium as part of a larger genetic unit, possibly as a composite transposon flanked by IS1216 elements.
