Survival and Transcriptomic Response of Clinically relevant pathogens on Surfaces in Relation to Probiotic and Traditional Cleaning Strategies

Prolonged survival of clinically relevant pathogens on inanimate surfaces represents a major concern in healthcare facilities. Contaminated surfaces can serve as reservoirs of potential pathogens and greatly hinder the prevention of healthcare-associated infections. Probiotic cleaning using environmental microorganisms to promote inter-species competition has been proposed as an alternative to traditional chemical-based cleaning using antimicrobials. Probiotic cleaning seeks to take advantage of ecological principles such as competitive exclusion and utilize benign microorganisms to inhibit viable pathogens on indoor surfaces. However, limited mechanistic study has yielded direct evidence that enables the scientific community to understand the stress response, or microbe-microbe interactions between healthcare-associated pathogens and probiotic bacteria. Therefore, to bridge this knowledge gap, we combined transcriptomics and traditional microbiology techniques to investigate the differential impact of chemical-based and probiotic surface cleaners on the survival of Acinetobacter baumannii and Klebsiella pneumoniae, two clinically important pathogens. Although probiotic Bacillus included in a commercialized All-Purpose Probiotic Cleaner persisted on surfaces for an extended period of time, surfaces contaminated with A. baumannii cleaned using chemical-based detergent with and without probiotic Bacillus showed no statistical difference in the viable colony forming units (CFUs) of A. baumannii. Similarly, for Klebsiella pneumoniae, there were negligible statistical differences in CFUs between probiotic and detergent cleaning scenarios. The transcriptome of A. baumannii with and without probiotic addition shared a high degree of similarity in overall gene expression, while the transcriptome of K. pneumoniae with and without probiotic addition differed in overall gene expression. Together, these results highlight the need to fully understand the underlying biological and ecological mechanisms for different pathogens and practical implications of probiotic indoor cleaning.

Effect of soya phosphatidylcholine and possible underlying mechanism on ischemia/reperfusion injury in isolated perfused rat heart: an experimental and computational study

This study was designed to assess the effect of soya phosphatidylcholine (SPC) against ischemia/reperfusion (I/R) injury and the possible underlying mechanism using experimental and computational studies. I/R injury was induced by global ischemia for 30 min followed by reperfusion for 120 min. The perfusion of the SPC was performed for 10 min before inducing global ischemia. In the mechanistic study, the involvement of specific cellular pathways was identified using various inhibitors such as ATP-dependent potassium channel (KATP) inhibitor (glibenclamide), protein kinase C (PKC) inhibitor (chelerythrine), non-selective nitric oxide synthase inhibitor (L-NAME), and endothelium remover (Triton X-100). The computational study of various ligands was performed on toll-like receptor 4 (TLR4) protein using AutoDock version 4.0. SPC (100 μM) significantly decreased the levels of cardiac damage markers and %infarction compared with the vehicle control (VC). Furthermore, cardiodynamics (indices of left ventricular contraction (dp/dtmax), indices of left ventricular relaxation (dp/dtmin), coronary flow, and antioxidant enzyme levels were significantly improved as compared with VC. This protective effect was attenuated by glibenclamide, chelerythrine, and Triton X-100, but it was not attenuated by L-NAME. The computational study showed a significant bonding affinity of SPC to the TLR4-MD2 complex. Thus, SPC reduced myocardial I/R injury in isolated perfused rat hearts, which might be governed by the KATP channel, PKC, endothelium response, and TLR4-MyD88 signaling pathway.

Isolation of Unusual N-Thiophenyl Ebselenamines and other Intermediates during the 77Se NMR Mechanistic Study of Azo-Bis-Ebselen: Their Antioxidant Behaviour against Oxidative Stress

Based on the traditional 77Se NMR spectroscopy investigation, a catalytic cycle for the formation of N-thiophenyl ebselenamine 12 involving diselenide 9, selenenyl sulfide 10 and ebselenamine 7a was reported by the reaction of azo-bis-ebselen 8 with PhSH and H2O2. The signals detected in the 77Se NMR spectrum corresponding to 7a, 10 and 12 were directly isolated from the NMR mixture. Mechanistic investigation for the formation of N-thiophenyl ebselenamine 12 was confirmed from an independent reaction of diselenide 9 and PhSSPh in the presence of H2O2. This was further supported by another diselenide 19 containing p-tolyl group with equimolar amount of H2O2 and PhSH in an independent experiment followed by the 77Se NMR spectroscopy, yielding similar observations. These results, which illustrated diselenide has been observed as the main precursor in the formation of all intermediates. The new novel selenium antioxidants quenched lipidperoxyl radicals much more efficiently than α-tocopherol and were regenerable by the aqueous ascorbic acid in a two-phase (chlorobenzene/water) azo-initiated peroxidation system. The notable benefit of the organoselenium biology, the novel ebselenamine analogues and their corresponding selenenyl sulfides were found to mimic the activity of the glutathione peroxidase enzymes better than ebselen in the coupled reductase assay.

Mechanistic Study on Gold(I)-Catalyzed Unsaturated Spiroketalization Reaction

The mechanism of metal-catalyzed spiroketalization of propargyl acetonide is explored by employing DFT with the B3LYP/6-31+G(d) method. Acetonide is used as a regioselective regulator in the formation of monounsaturated spiroketal. The energies of transition states, intermediates, reactants and products are calculated to provide new insight into the mechanism of the reaction. The energetic features, validation of the observed trends in regioselectivity are conferred in terms of electronic indices via FMO analysis. The presence of acetonide facilitates a stepwise spiroketalization as it masks the competing nucleophile, and thus hydroxyl group present, exclusively acts as a nucleophile. The vinyl gold intermediate 3 is formed from 2 via activation barrier TS1. This is the first ring formation, which is 6-exo-dig cyclization. The intermediate 3 is converted into allenyl ether 4, which isomerizes to the intermediate oxocarbenium ion 5 via activation barrier TS2. The intermediate 5 cyclizes to 6 via TS3. This is the second ring formation. The intermediate 6 on protodeauration turns into 6,6-monounsaturated spiroketal 7. It is concluded that acetonide as a protecting group serves the purpose, and thus a wide range of spiroketals can be prepared, regioselectivity.

Mouse Mesenchymal Stem Cell-derived Exosomal Mir-466f-3p Reverses Emt Process Through Inhibiting Akt/gsk3β Pathway via C-met in Radiation-induced Lung Injury

Background: Radiation-induced lung fibrosis (RILF) is a common complication of thoracic radiotherapy. Alveolar epithelial cells play a crucial role in lung fibrosis via epithelial-mesenchymal transition (EMT). Exosomes derived from mesenchymal stem cells own the beneficial properties to repair and regeneration of damaged tissues, however the underlying mechanisms remain poorly understood. Methods: Mouse mesenchymal stem cells-derived exosomes (mMSCs-Exo) were isolated by differential centrifugation, and their protective effects were assessed in vivo and in vitro , respectively. EMT-associated proteins were measured via western blot assay and/or immunofluorescence staining. The miRNA expression was measured by microarray assay and qPCR. Furthermore, bioinformatics prediction with KEGG analysis, luciferase assay, and rescue experiments were performed to explore the molecular mechanism underlying miR-466f-3p. Results: mMSCs-Exos were efficiently isolated ranging from 90-150 nm with high expression of exosomal markers (CD63, TSG101, and CD9). mMSCs-Exos administration efficiently relieved radiation-induced lung injury with less collagen deposition and lower levels of IL-1β and IL-6. Meanwhile, in vitro results showed mMSCs-Exos treatment obviously reversed EMT process induced by radiation. Among enriched miRNA cargo in exosomes, miR-466f-3p was primarily responsible for the protective effects via inhibition of AKT/GSK3β pathway. Our mechanistic study further demonstrated that c-MET was the direct target of miR-466f-3p, whose restoration partially abrogated mMSCs-Exo-mediated inhibition in both EMT process and AKT/GSK3β signaling activity induced by radiation. Conclusions: Our findings indicated that exosomal miR-466f-3p derived from mMSCs may possess anti-fibrotic properties and prevent radiation-induced EMT through inhibition of AKT/GSK3β via c-MET, providing a promising therapeutic modality for radiation-induced lung fibrosis.

In Vitro Anticancer Screening and Preliminary Mechanistic Study of A-Ring Substituted Anthraquinone Derivatives

Anthraquinone derivatives exhibit various biological activities, e.g., antifungal, antibacterial and in vitro antiviral activities. They are naturally produced in many fungal and plant families such as Rhamnaceae or Fabaceae. Furthermore, they were found to have anticancer activity, exemplified by mitoxantrone and pixantrone, and many are well known redox-active compounds. In this study, various nature inspired synthetic anthraquinone derivatives were tested against colon, prostate, liver and cervical cancer cell lines. Most of the compounds exhibit anticancer effects against all cell lines, therefore the compounds were further studied to determine their IC50-values. Of these compounds, 1,4-bis(benzyloxy)-2,3-bis(hydroxymethyl)anthracene-9,10-dione (4) exhibited the highest cytotoxicity against PC3 cells and was chosen for a deeper look into its mechanism of action. Based on flow cytometry, the compound was proven to induce apoptosis through the activation of caspases and to demolish the ROS/RNS and NO equilibrium in the PC3 cell line. It trapped cells in the G2/M phase. Western blotting was performed for several proteins related to the effects observed. Compound 4 enhanced the production of PARP and caspase-3. Moreover, it activated the conversion of LC3A/B-I to LC3A/B-II showing that also autophagy plays a role in its mechanism of action, and it caused the phosphorylation of p70 s6 kinase.