RESUMEN

Pesticides are chemical substances used to control, prevent, or destroy agricultural, domestic, and livestock pests. These compounds produce adverse changes in health, and they have been associated with the development of multiple chronic diseases. This study aimed to present a detailed review of the effect of pesticides on the oral cavity and the oral microbiome. In the oral cavity, pesticides alter and/or modify tissues and the microbiome, thereby triggering imbalance in the ecosystem, generating an inflammatory response, and activating hydrolytic enzymes. In particular, the imbalance in the oral microbiome creates a dysbiosis that modifies the number, composition, and/or functions of the constituent microorganisms and the local response of the host. Pesticide exposure alters epithelial cells, and oral microbiota, and disrupts the homeostasis of the oral environment. The presence of pesticides in the oral cavity predisposes the appearance of pathologies such as caries, periodontal diseases, oral cancer, and odontogenic infections. In this study, we analyzed the effect of organochlorines, organophosphates, pyrethroids, carbamates, bipyridyls, and triazineson oral cavity health and ecosystems.

Asunto(s)

Microbiota , Plaguicidas , Piretrinas , Carbamatos , Boca , Organofosfatos , Plaguicidas/toxicidad

RESUMEN

Bottom-up chemical synthesis to construct intricate molecules has been a profound challenge. An effective approach is to utilize organic ligands and metal ions, but the formation of a single product among other possible candidates has proven difficult for dissymmetric structures. We now report the synthesis of single isomeric complexes with dissymmetric structures using the mismatch in the coordination valences of macrocyclic homooligomers and metal ions. A series of amide-cyclodextrin derivatives possessing multiple 2,2'-bipyridyl (bpy) groups forms mononuclear complexes whose specific three bpy groups are linked in the fac-Λ configuration. The intermolecular coordination of the ß-cyclodextrin metal complex produces a dissymmetric cyclodextrin trimer as a single isomer, whose initially equivalent 21 (=7×3) bipyridylamide-pyranose units are placed in different environments. Furthermore, we realize chiral recognition of amino acid anions utilizing the distinctive amide groups arranged on the unsymmetrically fixed scaffold.

RESUMEN

Bacteria must be able to cope with harsh environments to survive. In Gram-negative bacteria like Pseudomonas species, resistance-nodulation-division (RND) transporters contribute to this task by pumping toxic compounds out of cells. Previously, we found that the RND system TtgABC of Pseudomonas putida KT2440 confers resistance to toxic metal chelators of the bipyridyl group. Here, we report that the incubation of a ttgB mutant in medium containing 2,2'-bipyridyl generated revertant strains able to grow in the presence of this compound. This trait was related to alterations in the pp_2827 locus (homolog of mexS in Pseudomonas aeruginosa). The deletion and complementation of pp_2827 confirmed the importance of the locus for the revertant phenotype. Furthermore, alteration in the pp_2827 locus stimulated expression of the mexEF-oprN operon encoding an RND efflux pump. Deletion and complementation of mexF confirmed that the latter system can compensate the growth defect of the ttgB mutant in the presence of 2,2'-bipyridyl. To our knowledge, this is the first report on a role of pp_2827 (mexS) in the regulation of mexEF-oprN in P. putida KT2440. The results expand the information about the significance of MexEF-OprN in the stress response of P. putida KT2440 and the mechanisms for coping with bipyridyl toxicity.

RESUMEN

2,2'-Bipyridyls have been utilized as indispensable ligands in metal-catalyzed reactions. The most streamlined approach for the synthesis of 2,2'-bipyridyls is the dehydrogenative dimerization of unfunctionalized pyridine. Herein, we report on the palladium-catalyzed dehydrogenative synthesis of 2,2'-bipyridyl derivatives. The Pd catalysis effectively works with an AgI salt as the oxidant in the presence of pivalic acid. A variety of pyridines regioselectively react at the C2-positions. This dimerization method is applicable for challenging substrates such as sterically hindered 3-substituted pyridines, where the pyridines regioselectively react at the C2-position. This reaction enables the concise synthesis of twisted 3,3'-disubstituted-2,2'-bipyridyls as an underdeveloped class of ligands.

RESUMEN

A new bipyridyl derivative 1 bearing rhodamine B as visible fluorophore was designed, synthesized and characterized as a fluorescent and colorimetric sensor for metal ions. Interaction with Cu(2+), Zn(2+), Cd(2+), Hg(+), and Hg(2+) ions was followed by UV/Vis and emission spectroscopy. Upon addition of these metal ions, different colorimetric and fluorescent responses were observed. "Off-on-off" (Cu(2+), Zn(2+), and Hg(2+)) and "off-on" (Hg(+) and Cd(2+)) systems were obtained. Probe 1 was explored to mimic XOR and OR logic operations for the simultaneous detection of Hg(+)-Cu(2+) and Hg(+)-Zn(2+) pairs, respectively. DFT calculations were also performed to gain insight into the lowest-energy gas-phase conformation of free receptor 1 as well as the atomistic details of the coordination modes of the various metal ions.