Selective Luminescent Chemosensing of Chloride Based on a Cyclometalated Platinum(II) Complex in Water: Crystal Structures, Spectroscopic Studies, Extraction, and Bioimaging.

Selective anion sensing by luminescent chemosensors capable of operating in aqueous conditions is a central field of modern supramolecular chemistry that impacts analytical and biological chemistry. A cationic cyclometalated [Pt(N^C^N)NCCH3]OTf complex, 1 [N^C^N = 1,3-bis(1-(p-tolyl)-benzimidazol-2'-yl)benzene, OTf = triflate], was prepared, structurally described by single-crystal X-ray diffraction and studied in-depth as a luminescent chemosensor for anions in aqueous phase and solid state. A series of related neutral [Pt(N^C^N)X] complexes (X = Cl, 2; CN, 3 and I, 4) were formed readily upon treatment of 1 with the respective NaX salt in aqueous media and were described structurally by X-ray diffraction. Complex 1 is hydrostable with phosphorescent green emission originated by intraligand transitions, and [dyz(Pt) → π*(N^C^N)] charge transfer transitions, as evidenced by TD-DFT calculations and lifetime. Additions of halides, pseudohalides, oxyanions, and dicarboxylates to a neutral aqueous solution of 1 modified its green emission intensity with a pronounced affinity (K = 1.5 × 105 M-1) and turn-on signal toward Cl- within the micromolar concentration range. Pt complex 1 is two orders of magnitude more selective for Cl- than the other halides, CN- and basic oxyanions. Such Cl- affinity for a metal-based chemosensor in aqueous media is still rare. On the basis of X-ray crystallographic analysis and multiple spectroscopic tools (NMR, UV-vis, luminescence, MS, lifetimes) the origin of this selectivity hinges on the cooperative three-point recognition involving one coordination bond (Pt-Cl) and two convergent short C-H···Cl- contacts. This strong affinity and efficient optical response can be utilized in quantitative Cl- sensing in real samples and solid-liquid extractions. Additionally, chloro-Pt complex, 2 may be relevant to bioimaging as a marker for cell nuclei, as revealed by its emission within living cells and intracellular distribution by confocal microscopic studies. These results demonstrate the usefulness of the new water-stable luminescent Pt-N^C^N complexes as effective analytical tools in anion sensing and extraction agents.

Prevalence, main serovars and anti-microbial resistance profiles of non-typhoidal Salmonella in poultry samples from the Americas: A systematic review and meta-analysis.

Poultry and poultry-derived products such as meat and eggs are among the main sources of non-typhoidal Salmonella (NTS) transmission to humans. Therefore, we performed a systematic review and used random-effects meta-analyses to (1) estimate the prevalence of NTS in poultry samples from birds, products and subproducts and environmental samples, (2) examine the diversity and frequency of their serovars and (3) estimate the prevalence and profiles of anti-microbial resistance (AMR) in NTS isolates reported in studies from the Americas. We included 157 studies from 15 countries comprising 261,408 poultry samples and estimated an overall pooled prevalence of 17.9% (95% Confidence Interval: 10.8-26.3) in birds, 21.8% (17.7-26.1) in products and subproducts and 29.5% (24.2-35.1) in environmental samples. At the national level, the prevalence of NTS was heterogeneous across countries with the highest values in Mexico, the United States and Canada. In total, 131 serovars were identified from 13,388 isolates; Heidelberg, Kentucky, Enteritidis and Typhimurium were the most prevalent in the overall top 10 ranking (range 6.5%-20.8%). At the national level, Enteritidis and Typhimurium were identified in most of the countries, though with national differences in their ranks. The prevalence of AMR increased from 24.1% for 1 antibiotic to 36.2% for 2-3 antibiotics and 49.6% for ≥ 4 antibiotics. Kentucky, Heidelberg, Typhimurium and Enteritidis were the serovars with the highest prevalence of AMR. Besides, tetracycline, ampicillin, streptomycin, ceftiofur and amoxicillin-clavulanic acid were the most frequent antibiotics to which NTS showed resistance. In conclusion, NTS was distributed through the avian production chain with high and heterogeneous values of prevalence in poultry samples. Besides, there were distinctive patterns of serovars distribution across countries and an alarming prevalence of AMR among zoonotic serovars.

Prevalence of Salmonella enterica serovar Albany in captive zoo wild animals in the Culiacán Zoo in Mexico.

Salmonellosis is an important zoonotic disease but little is known about the role that free-living animals play as carriers of this pathogen. Moreover, the primary route of infection in the wild needs to be elucidated. The aim of this study was to determine the source and the route of transmission of Salmonella enterica serovar Albany (S. Albany) infection in captive zoo wild animals in the Culiacán Zoo. A total of 267 samples were analyzed including 220 fecal samples from zoo animals, 15 fecal samples from rodents, 5 pooled samples each of two insects (Musca domestica and Periplaneta americana), and 22 samples of animal feed. We detected S. Albany in 28 (10.5%) of the samples analyzed, including in samples from raw chicken meat. Characterization of isolates was performed by serotyping and pulsed-field gel electrophoresis. All isolates shared a single pulsed-field gel electrophoresis profile, indicating a possible common origin. These data suggest that the infected meat consumed by the wild felines was the primary source of infection in this zoo. It is likely that the pathogen was shed in the feces and disseminated by insects and rats to other locations in the zoo.

Up-regulation of HLA class-I antigen expression and antigen-specific CTL response in cervical cancer cells by the demethylating agent hydralazine and the histone deacetylase inhibitor valproic acid.

BACKGROUND: DNA hypermethylation and histone deacetylation are epigenetic events that contribute to the absence or downregulated expression of different components of the tumor recognition complex. These events affect the processing and presentation of antigenic peptides to CTLs by HLA class-I molecules. In this work evaluated the effect of the DNA hypomethylating agent hydralazine and the histone deacetylase inhibitor valproic acid, on the expression of HLA class-I molecules and on the antigen-specific immune recognition of cervical cancer cells. METHODS: Cell lines C33A (HPV-), CaSki (HPV-16+) and MS751 (HPV-18+) were treated with hydralazine and valproic acid to assess the expression of HLA class-I molecules by flow cytometry and RT-PCR. Promoter methylation of HLA class-I -A, -B and C, was also evaluated by Methylation-Specific PCR. Primary cervical tumors of four HLA-A*0201 allele patients were typed for HPV and their CTL's stimulated in vitro with the T2 cell line previously loaded with 50 microM of the HPV peptides. Cytotoxicity of stimulated CTL's was assayed against Caski and MS751 cells pre-treated with hydralazine and valproic acid. RESULTS: Valproic acid and hydralazine/valproic acid up-regulated the constitutive HLA class-I expression as evaluated by flow cytometry and RT-PCR despite constitutive promoter demethylation at these loci. Hydralazine and valproic acid in combination but no IFN-gamma hyperacetylated histone H4 as evaluated by ChiP assay. The antigenic immune recognition of CaSki and MS751 cells by CTLs specific to HPV-16/18 E6 and E7-derived epitopes, was increased by VA and H/VA and the combination of H/VA/IFN-gamma. CONCLUSION: These results support the potential use of hydralazine and valproic acid as an adjuvant for immune intervention in cervical cancer patients whenever clinical protocols based on tumor antigen recognition is desirable, like in those cases where the application of E6 and E7 based therapeutic vaccines is used.