Coastal aquatic pollutants degradation using ZnCo2O4 nanorods.

Water pollution has caused problems in coastal areas, rivers, lakes, and other important water sources around the world as a result of inappropriate waste management. Meanwhile, these pollutants are harmful to humans and aquatic life. Textile dye effluent methyl orange (MO) was used in this work for dye degradation studies employing nanocomposites. As a result, the importance of synthesizing pure ZnO and Co3O4 nanoparticles with composites of ZnCo2O4 (zinc cobaltite) nanorods in three various proportions (90:10, 75:25, and 50:50) is emphasized in this study. Many advanced approaches were used to assess the various features of these materials, including size and shape. Fourier transform infrared (FT-IR) spectroscopy was used to determine the vibrational modes of the materials. The absorption measurements were then carried out using UV-vis spectroscopic techniques, and the photocatalytic breakdown of MO was done under visible light irradiation. The findings revealed that pure materials were inadequate for visible light activity, resulting in decreased degradation efficiencies. Spinel cobaltite structures have potential degradation efficiency under visible light, while ZnCo2O4 (50:50) catalyst has superior degradation efficiency of 59.8% over MO. The crystallite size, morphology, functional group, absorption wavelength, and band gap all play important roles in enhancing the material's photocatalytic activity under visible light. Meanwhile, ZnCo2O4 spinel structures are crucial for increasing charge carriers and reducing electron-hole recombination. As a result, zinc cobaltite minerals are widely used in industrial dye degradation applications.

Saroglitazar suppresses the hepatocellular carcinoma induced by intraperitoneal injection of diethylnitrosamine in C57BL/6 mice fed on choline deficient, l-amino acid- defined, high-fat diet.

BACKGROUND: Saroglitazar is a novel PPAR-α/γ agonist with predominant PPAR-α activity. In various preclinical models, saroglitazar has been shown to prevent & reverse symptoms of NASH. In view of these observations, and the fact that NASH is a progressive disease leading to HCC, we hypothesized that saroglitazar may prevent the development of HCC in rodents. METHODS: HCC was induced in C57BL/6 mice by a single intraperitoneal injection of 25 mg/kg diethylnitrosamine (DEN) at the age of 4 weeks and then feeding the animal a choline-deficient, L-amino acid- defined, high-fat diet (CDAHFD) for the entire study duration. Eight weeks after initiation of CDAHFD, saroglitazar (1 and 3 mg/kg) treatment was started and continued for another 27 weeks. RESULTS: Saroglitazar treatment significantly reduced the liver injury markers (serum ALT and AST), reversed hepatic steatosis and decreased the levels of pro-inflammatory cytokines like TNF-α in liver. It also resulted in a marked increase in serum adiponectin and osteopontin levels. All disease control animals showed hepatic tumors, which was absent in saroglitazar (3 mg/kg)- treatment group indicating 100% prevention of hepatic tumorigenesis. This is the first study demonstrating a potent PPARα agonist causing suppression of liver tumors in rodents, perhaps due to a strong anti-NASH activity of Saroglitazar that overrides its rodent-specific peroxisome proliferation activity. CONCLUSION: The data reveals potential of saroglitazar for chemoprevention of hepatocellular carcinoma in patients with NAFLD/NASH.

Fluorescent A2A and A3 adenosine receptor antagonists as flow cytometry probes.

Adenosine receptor (AR) ligands are being developed for metabolic, cardiovascular, neurological, and inflammatory diseases and cancer. The ease of drug discovery is contingent on the availability of pharmacological tools. Fluorescent antagonist ligands for the human A2A and A3ARs were synthesized using two validated pharmacophores, 1,3-dipropyl-8-phenylxanthine and triazolo[1,5-c]quinazolin-5-yl)amine, which were coupled to eight reporter fluorophores: AlexaFluor, JaneliaFluor (JF), cyanine, and near infrared (NIR) dyes. The conjugates were first screened using radioligand binding in HEK293 cells expressing one of the three AR subtypes. The highest affinities at A2AAR were Ki 144-316 nM for 10, 12, and 19, and at A3AR affinity of Ki 21.6 nM for 19. Specific binding of JF646 conjugate MRS7774 12 to the HEK293 cell surface A2AAR was imaged using confocal microscopy. Compound 19 MRS7535, a triazolo[1,5-c]quinazolin-5-yl)amine containing a Sulfo-Cy7 NIR dye, was suitable for A3AR characterization in whole cells by flow cytometry (Kd 11.8 nM), and its bitopic interaction mode with an A3AR homology model was predicted. Given its affinity and selectivity (11-fold vs. A2AAR, ~ 50-fold vs. A1AR and A2BAR) and a good specific-to-nonspecific binding ratio, 19 could be useful for live cell or potentially a diagnostic in vivo NIR imaging tool and/or therapy targeting the A3AR.

Anaerobic Degradation of Naphthalene and Pyrene by Sulfate-Reducing Cultures Enriched from Former Manufactured Gas Plant Soil.

Biodegradation of polycyclic aromatic hydrocarbons (PAHs) under completely anaerobic sulfate-reducing conditions is an energetically challenging process. To date, anaerobic degradations of only two-ringed naphthalene and three-ringed phenanthrene by sediment-free and enriched sulfate-reducing bacteria have been reported. In this study, sulfate-reducing enrichment cultures capable of degrading naphthalene and four-ringed PAH, pyrene, were enriched from a contaminated former gas plant site soil. Bacterial community composition analysis revealed that a naphthalene-degrading enrichment culture, MMNap, was dominated (84.90%) by a Gram-positive endospore-forming member of the genus Desulfotomaculum with minor contribution (8.60%) from a member of Clostridium. The pyrene-degrading enrichment, MMPyr, was dominated (97.40%) by a species of Desulfotomaculum. The sequences representing the Desulfotomaculum phylotypes shared 98.80% similarity to each other. After 150 days of incubation, MMNap degraded 195 µM naphthalene with simultaneous reduction of sulfate and accumulation of sulfide. Similarly, MMPyr degraded 114 µM pyrene during 180 days of incubation with nearly stochiometric sulfate consumption and sulfide accumulation. In both cases, the addition of sulfate reduction inhibitor, molybdate (20 mM), resulted in complete cessation of the substrate utilization and sulfate reduction that clearly indicated the major role of the sulfate-reducing Desulfotomaculum in biodegradation of the two PAHs. This study is the first report on anaerobic pyrene degradation by a matrix-free, strictly anaerobic, and sulfate-reducing enrichment culture.

Progressive yield of nickel cobaltite nanocubes for visible light utilization and degrading activities of methyl orange dye pollutant.

In this study, pure cobalt oxide (Co3O4) as well as nickel cobaltite (NiCo2O4) were investigated with their capacity of degradation efficiency for textile dyes like methyl orange (MO) employing visible light irradiation. Two variable concentrations of nickel cobaltite (NiCo2O4) with 75:25 and 50:50 wt ratios along with the pure metal oxides were synthesized by thermal decomposition method and analyzed by various sophisticated instruments. Initially, the structural characteristics described the fine crystalline nature of NiCo2O4 and also exhibits reduced size than the pure component material (Co3O4). Besides, NiCo2O4 catalysts represented nano cubic shaped particles, and also their coordinating functional groups were evaluated. Further, the absorption wavelength confirms the two band positions of NiCo2O4 which leads to promote visible light absorption, and degrading efficiency of about 47.5% for NiCo2O4 (75:25) sample compared with NiCo2O4 (50:50) which produced only 26.3% degradation. This higher efficiency of the former was due to high crystallinity and interfacial charge transfer of combined Ni2+, Ni3+, Co2+ and Co3+ redox couples. This consecutively produces effective OH radicals that brought the degradation effectively under visible light. The recycling capacity up to 5 repeated cycles has been studied with the NiCo2O4 (75:25) and therefore the catalyst can further be used in other dye degradation.

Nef inhibits HIV transcription and gene expression in astrocytes and HIV transmission from astrocytes to CD4+ T cells.

HIV infects astrocytes in a restricted manner but leads to abundant expression of Nef, a major viral factor for HIV replication and disease progression. However, the roles of Nef in HIV gene expression and replication in astrocytes and viral transfer from astrocytes to CD4+ T cells remain largely unclear. In this study, we attempted to address these issues by transfecting human primary astrocytes with HIV molecular clones with intact Nef and without Nef (a nonsense Nef mutant) and comparing gene expression and replication in astrocytes and viral transfer from astrocytes to CD4+ T cells MT4. First, we found that lack of Nef expression led to increased extracellular virus production from astrocytes and intracellular viral protein and RNA expression in astrocytes. Using a HIV LTR-driven luciferase reporter gene assay, we showed that ectopic Nef expression alone inhibited the HIV LTR promoter activity in astrocytes. Consistent with the previously established function of Nef, we showed that the infectivity of HIV derived from astrocytes with Nef expression was significantly higher than that with no Nef expression. Next, we performed the co-culture assay to determine HIV transfer from astrocytes transfected to MT4. We showed that lack of Nef expression led to significant increase in HIV transfer from astrocytes to MT4 using two HIV clones. We also used Nef-null HIV complemented with Nef in trans in the co-culture assay and demonstrated that Nef expression led to significantly decreased HIV transfer from astrocytes to MT4. Taken together, these findings support a negative role of Nef in HIV replication and pathogenesis in astrocytes.

Impact of Nitrate and Ammonium Concentrations on Co-Culturing of Tetradesmus obliquus IS2 with Variovorax paradoxus IS1 as Revealed by Phenotypic Responses.

Mutual interactions in co-cultures of microalgae and bacteria are well known for establishing consortia and nutrient uptake in aquatic habitats, but the phenotypic changes in terms of morphological, physiological, and biochemical attributes that drive these interactions have not been clearly understood. In this novel study, we demonstrated the phenotypic response in a co-culture involving a microalga, Tetradesmus obliquus IS2, and a bacterium, Variovorax paradoxus IS1, grown with varying concentrations of two inorganic nitrogen sources. Modified Bold's basal medium was supplemented with five ratios (%) of NO3-N:NH4-N (100:0, 75:25, 50:50, 25:75, and 0:100), and by maintaining N:P Redfield ratio of 16:1. The observed morphological changes in microalga included an increase in granularity and a broad range of cell sizes under the influence of increased ammonium levels. Co-culturing in presence of NO3-N alone or combination with NH4-N up to equimolar concentrations resulted in complete nitrogen uptake, increased growth in both the microbial strains, and enhanced accumulation of carbohydrates, proteins, and lipids. Total chlorophyll content in microalga was also significantly higher when it was grown as a co-culture with NO3-N and NH4-N up to a ratio of 50:50. Significant upregulation in the synthesis of amino acids and sugars and downregulation of organic acids were evident with higher ammonium uptake in the co-culture, indicating the regulation of carbon and nitrogen assimilation pathways and energy synthesis. Our data suggest that the co-culture of strains IS1 and IS2 could be exploited for effluent treatment by considering the concentrations of inorganic sources, particularly ammonium, in the wastewaters.

Extracellular Polymeric Substances Drive Symbiotic Interactions in Bacterial‒Microalgal Consortia.

The importance of several factors that drive the symbiotic interactions between bacteria and microalgae in consortia has been well realised. However, the implication of extracellular polymeric substances (EPS) released by the partners remains unclear. Therefore, the present study focused on the influence of EPS in developing consortia of a bacterium, Variovorax paradoxus IS1, with a microalga, Tetradesmus obliquus IS2 or Coelastrella sp. IS3, all isolated from poultry slaughterhouse wastewater. The bacterium increased the specific growth rates of microalgal species significantly in the consortia by enhancing the uptake of nitrate (88‒99%) and phosphate (92‒95%) besides accumulating higher amounts of carbohydrates and proteins. The EPS obtained from exudates, collected from the bacterial or microalgal cultures, contained numerous phytohormones, vitamins, polysaccharides and amino acids that are likely involved in interspecies interactions. The addition of EPS obtained from V. paradoxus IS1 to the culture medium doubled the growth of both the microalgal strains. The EPS collected from T. obliquus IS2 significantly increased the growth of V. paradoxus IS1, but there was no apparent change in bacterial growth when it was cultured in the presence of EPS from Coelastrella sp. IS3. These observations indicate that the interaction between V. paradoxus IS1 and T. obliquus IS2 was mutualism, while commensalism was the interaction between the bacterial strain and Coelastrella sp. IS3. Our present findings thus, for the first time, unveil the EPS-induced symbiotic interactions among the partners involved in bacterial‒microalgal consortia.

Advancements on sustainable microbial fuel cells and their future prospects: A review.

A microbial fuel cell (MFC) is a sustainable device that produces electricity. The main components of MFC are electrodes (anode & cathode) and separators. The MFC's performance is ascertained by measuring its power density. Its components and other parameters, such as cell design and configuration, operation parameters (pH, salinity, and temperature), substrate characteristics, and microbes present in the substrate, all influence its performance. MFC can be scaled up and commercialized using low-cost materials without affecting its performance. Hence the choice of materials plays a significant role. In the past, precious and non-precious metals were mostly used. These were replaced by a variety of low-cost carbonaceous and non-carbonaceous materials. Nano materials, activated compounds, composite materials, have also found their way as components of MFC materials. This review describes the recently reported modified electrodes (anode and cathode), their improvisation, their merits, pollutant removal efficiency, and associated power density.

Halides and oxyhalides-based photocatalysts for abatement of organic water contaminants - An overview.

Recently, halides (silver halides, AgX; perosvkite halides, ABX3) and oxyhalides (bismuth oxyhalides, BiOX) based nanomaterials are noticeable photocatalysts in the degradation of organic water pollutants. Therefore, we review the recent reports to explore improvement strategies adopted in AgX, ABX3 and BiOX (X = Cl, Br and I)-based photocatalysts in water pollution remediation. Herein, the photocatalytic degradation performances of each type of these photocatalysts were discussed. Strategies such as tailoring the morphology, crystallographic facet exposure, surface area, band structure, and creation of surface defects to improve photocatalytic activities of pure halides and BiOCl photocatalysts are emphasized. Other strategies like metal ion and/or non-metal doping and construction of composites, adopted in these photocatalysts were also reviewed. Furthermore, the way of production of active radicals by these photocatalysts under ultraviolet/visible light source is highlighted. The deciding factors such as structure of pollutant, light sources and other parameters on the photocatalytic performances of these materials were also explored. Based on this literature survey, the need of further research on AgX, ABX3 and BiOX-based photocatalysts were suggested. This review might be beneficial for researchers who are working in halides and oxyhalides-based photocatalysis for water treatment.

Electrochemical detection of hydrogen peroxide using micro and nanoporous CeO2 catalysts.

In this research work, focus has been made on a glassy carbon electrode (GCE) modified commercial micro and synthesized nano-CeO2 for the detection of hydrogen peroxide (H2O2). Firstly, CeO2 nanoleaves were prepared by solvothermal route. Both commercially available micro CeO2 and synthesized nano-CeO2 structures were analyzed by different characterization techniques. The Raman spectra of synthesized nano CeO2 has more oxygen vacancies than micro CeO2. SEM images revealed that the synthesized CeO2 acquired leaf-like morphology. The catalyst nano CeO2 offered mesoporosity from nitrogen adsorption-desorption isotherms with massive sites of activation for increasing efficiency. Experiments on determining H2O2 using micro CeO2 or nano-CeO2/GCE was conducted using cyclic voltammetry (CV) and amperometry. Enhanced H2O2 reduction peak current with lower potential was observed in nano-CeO2/GCE. The influence of scan rate and H2O2 concentration on the performance of nano-CeO2/GCE were also studied. The obtained results have indicated that nano-CeO2/GCE showed improved electrochemical sensing behavior towards the reduction of H2O2 than micro-CeO2/GCE and bare GCE. A linear relationship was obtained over 0.001 µM-0.125 µM concentration of H2O2, with good sensitivity 141.96 µA µM-1 and low detection limit of 0.4 nM. Hence, the present nano-CeO2 system will have a great potential with solvothermal synthesis approach in the development of electrochemical sensors.

Long-term Outcomes of Percutaneous Coronary Intervention in Patients with Prior Coronary Artery Bypass Grafting.

BACKGROUND Patients with a prior coronary artery bypass graft (CABG) may have a need for repeat revascularization, which is typically attempted first via percutaneous coronary intervention (PCI) of either a bypass graft or native vessel. Long-term outcomes of native vessel compared to graft PCI after CABG have not yet been explored in a large institution study. METHODS Patients with history of prior CABG who underwent PCI at our institution during 2010-2018 were included. Baseline characteristics and long-term outcomes of up to 5 years were compared between native vessel and bypass graft PCI groups. Cox regression was used to adjust for significant covariates in estimation of risk and calculation of hazard ratios. RESULTS During the study, 4,251 patients with a prior CABG underwent PCI. Native vessel PCI represented 67.1% (n=2,851) of the cohort. After adjusting for significant covariates, bypass graft PCI compared to native vessel PCI had a higher risk of overall mortality (HR 1.15; 95% CI, 1.04-1.29; p<0.05), all-cause readmission (HR 1.16; 95% CI, 1.1-1.3; p<0.05), readmission for PCI (HR 1.25; 95% CI, 1.13-1.38; p<0.05), readmission for heart failure (HR 1.16; 95% CI, 1.06-1.26; p<0.05), and composite of myocardial infarction and revascularization (HR 1.23; 95% CI, 1.12-1.35; p<0.05). CONCLUSIONS Among patients with prior CABG, bypass graft PCI compared to native vessel PCI was associated with higher risk of adverse long-term outcomes.

Pathophysiological Role and Medicinal Chemistry of A2A Adenosine Receptor Antagonists in Alzheimer's Disease.

The A2A adenosine receptor is a protein belonging to a family of four GPCR adenosine receptors. It is involved in the regulation of several pathophysiological conditions in both the central nervous system and periphery. In the brain, its localization at pre- and postsynaptic level in striatum, cortex, hippocampus and its effects on glutamate release, microglia and astrocyte activation account for a crucial role in neurodegenerative diseases, including Alzheimer's disease (AD). This ailment is considered the main form of dementia and is expected to exponentially increase in coming years. The pathological tracts of AD include amyloid peptide-ß extracellular accumulation and tau hyperphosphorylation, causing neuronal cell death, cognitive deficit, and memory loss. Interestingly, in vitro and in vivo studies have demonstrated that A2A adenosine receptor antagonists may counteract each of these clinical signs, representing an important new strategy to fight a disease for which unfortunately only symptomatic drugs are available. This review offers a brief overview of the biological effects mediated by A2A adenosine receptors in AD animal and human studies and reports the state of the art of A2A adenosine receptor antagonists currently in clinical trials. As an original approach, it focuses on the crucial role of pharmacokinetics and ability to pass the blood-brain barrier in the discovery of new agents for treating CNS disorders. Considering that A2A receptor antagonist istradefylline is already commercially available for Parkinson's disease treatment, if the proof of concept of these ligands in AD is confirmed and reinforced, it will be easier to offer a new hope for AD patients.

Robust Stability Analysis of Delayed Stochastic Neural Networks via Wirtinger-Based Integral Inequality.

We discuss stability analysis for uncertain stochastic neural networks (SNNs) with time delay in this letter. By constructing a suitable Lyapunov-Krasovskii functional (LKF) and utilizing Wirtinger inequalities for estimating the integral inequalities, the delay-dependent stochastic stability conditions are derived in terms of linear matrix inequalities (LMIs). We discuss the parameter uncertainties in terms of norm-bounded conditions in the given interval with constant delay. The derived conditions ensure that the global, asymptotic stability of the states for the proposed SNNs. We verify the effectiveness and applicability of the proposed criteria with numerical examples.

Relationship between predicting bleeding complication in patients undergoing stent implantation and subsequent dual antiplatelet therapy (PRECISE-DAPT) score and mortality among patients with atrial fibrillation undergoing percutaneous coronary intervention.

BACKGROUND: The predicting bleeding complication in patients undergoing stent implantation and subsequent dual antiplatelet therapy, PRECISE-DAPT (P-DAPT) score has been validated in large cohorts as an effective tool in predicting bleeding complication after dual antiplatelet therapy (DAPT) as well as in predicting in-hospital mortality. The implication of using this score to predict outcomes, including mortality in patients with atrial fibrillation (AF) undergoing PCI is unknown. OBJECTIVE: Role of P-DAPT score to study clinical outcomes, including mortality, hospitalization, and major bleeding, particularly among patients with AF. METHODS: This is a retrospective observational study of 18,850 consecutive patients who underwent percutaneous coronary intervention (PCI) across a large multihospital healthcare system from 2010 to 2019. Patients were stratified into four groups depending on the presence or absence of AF and P-DAPT score, with score ≥ 25 defined as high risk. The primary outcome was all-cause mortality. The secondary outcomes evaluated were hospitalization and major bleeding. RESULTS: In the unadjusted analyses, a P-DAPT score ≥ 25, in both AF and non-AF population, was associated with increased mortality, hospitalization, and bleeding. After adjusting for baseline covariates, no significant differences in major bleeding risk were found across the four groups. However, a P-DAPT score of ≥25 in AF patients was associated with a higher risk for hospitalizations related to cardiovascular causes (HR: 2.15 95% CI 2.00-2.3, p < .0001). Among AF patients, P-DAPT score ≥ 25 was found to be strongly associated with mortality (HR 3.5; 95% CI 2.95-4.25, p < .0001) as compared with AF patients with score < 25 (HR 1.18, 95% CI 0.88-1.54, p = .26). CONCLUSION: In this large cohort of patients undergoing PCI, the P-DAPT score can help to identify patients at high risk for long-term mortality, particularly among those with atrial fibrillation.

Pharmacological characterization of DPTN and other selective A3 adenosine receptor antagonists.

The A3 adenosine receptor (AR) is emerging as an attractive drug target. Antagonists are proposed for the potential treatment of glaucoma and asthma. However, currently available A3AR antagonists are potent in human and some large animals, but weak or inactive in mouse and rat. In this study, we re-synthesized a previously reported A3AR antagonist, DPTN, and evaluated its affinity and selectivity at human, mouse, and rat ARs. We showed that DPTN, indeed, is a potent A3AR antagonist for all three species tested, albeit a little less selective for mouse and rat A3AR in comparison to the human A3AR. DPTN's Ki values at respective A1, A2A, A2B, and A3 receptors were (nM) 162, 121, 230, and 1.65 (human); 411, 830, 189, and 9.61 (mouse); and 333, 1147, 163, and 8.53 (rat). Its antagonist activity at both human and mouse A3ARs was confirmed in a cyclic AMP functional assay. Considering controversial use of currently commercially available A3AR antagonists in rats and mice, we also re-examined other commonly used and selective A3AR antagonists under the same experimental conditions. The Ki values of MRS1523 were shown to be 43.9, 349, and 216 nM at human, mouse, and rat A3ARs, respectively. MRS1191 and MRS1334 showed incomplete inhibition of [125I]I-AB-MECA binding to mouse and rat A3ARs, while potent human A3AR antagonists, MRS1220, MRE3008F20, PSB10, PSB-11, and VUF5574 were largely inactive. Thus, we demonstrated that DPTN and MRS1523 are among the only validated A3AR antagonists that can be possibly used (at an appropriate concentration) in mouse or rat to confirm an A3AR-related mechanism or function.

Recent progress in green and biopolymer based photocatalysts for the abatement of aquatic pollutants.

Enormous research studies on the abatement of anthropogenic aquatic pollutants including organic dyes, pesticides, cosmetics, antibiotics and inorganic species by using varieties of semiconductor photocatalysts have been reported in recent decades. Besides, many of these photocatalysts suffer in real applications owing to their high production cost and low stability. In many cases, the photocatalysts themselves are being considered as secondary pollutants. To eliminate these drawbacks, the green synthesized photocatalysts and the use of biopolymers as photocatalyst supports are considered in recent years. In this context, recent developments in green synthesized metals, metal oxides, other metal compounds, and carbon based photocatalysts in water purification are critically reviewed. Furthermore, the pivotal role of biopolymers including chitin, chitosan, cellulose, natural gum, hydroxyapatite, alginate in photocatalytic removal of aquatic pollutants is comprehensively reviewed. The presence of functional groups, electron trapping ability, biocompatibility, natural occurrence, and low production cost are the major reasons for using biopolymers in photocatalysis. Finally, the summary and conclusion are presented along with existing challenges in this research area.

Dynamics of coupled modified Rössler oscillators: The role of nonisochronicity parameter.

The amplitude-dependent frequency of the oscillations, termed nonisochronicity, is one of the essential characteristics of nonlinear oscillators. In this paper, the dynamics of the Rössler oscillator in the presence of nonisochronicity is examined. In particular, we explore the appearance of a new fixed point and the emergence of a coexisting limit-cycle and quasiperiodic attractors. We also describe the sequence of bifurcations leading to synchronized, desynchronized attractors and oscillation death states in the coupled Rössler oscillators as a function of the strength of nonisochronicity and coupling parameters. Furthermore, we characterize the multistability of the coexisting attractors by plotting the basins of attraction. Our results open up the possibilities of understanding the emergence of coexisting attractors and into a qualitative change of the collective states in coupled nonlinear oscillators in the presence of nonisochronicity.

ERK inhibition effectively overcomes acquired resistance of epidermal growth factor receptor-mutant non-small cell lung cancer cells to osimertinib.

BACKGROUND: Osimertinib (AZD9291), a third-generation, mutation-selective epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (EGFR-TKI), is an approved drug for patients who have non-small cell lung cancer (NSCLC) with activating EGFR mutations or those harboring a resistant T790M mutation. Unfortunately, all patients eventually relapse and develop resistance to osimertinib. The current study addressed whether ERK inhibition exerts effects similar to those produced by MEK inhibition in overcoming acquired resistance to osimertinib. METHODS: Drug effects on cell and tumor growth were assessed by measuring cell number alterations and colony formation in vitro and with xenografts in nude mice in vivo. Apoptosis was assessed with annexin V/flow cytometry and protein cleavage. Protein alterations in cells were detected with Western blot analysis. Gene overexpression and knockout were achieved with lentiviral infection and CRISPR/Cas9, respectively. RESULTS: The combination of osimertinib with an ERK inhibitor synergistically decreased the survival of osimertinib-resistant cell lines with enhanced induction of apoptosis and effectively inhibited the growth of osimertinib-resistant xenografts in nude mice. Moreover, the combination of an MEK or ERK inhibitor with a first-generation (eg, erlotinib) or second-generation (eg, afatinib) EGFR-TKI also very effectively inhibited the growth of osimertinib-resistant cells in vitro and of tumors in vivo, although these cell lines were cross-resistant to first-generation or second-generation EGFR-TKIs. CONCLUSIONS: The current findings emphasize the importance of targeting MEK/ERK signaling in maintaining the long-term benefit of osimertinib through overcoming acquired resistance to osimertinib, warranting further investigation of this therapeutic strategy to improve the therapeutic efficacy of osimertinib in the clinic.

Substrate Flexibility of the Flavin-Dependent Dihydropyrrole Oxidases PigB and HapB Involved in Antibiotic Prodigiosin Biosynthesis.

In the biosynthesis of the tripyrrolic pigment prodigiosin, PigB is a predicted flavin-dependent oxidase responsible for the formation of 2-methyl-3-amylpyrrole (MAP) from a dihydropyrrole. To prove which dihydropyrrole is the true intermediate, both possibilities, 5-methyl-4-pentyl-3,4-dihydro-2H-pyrrole (5 a, resulting from transamination of the aldehyde of 3-acetyloctanal) and 2-methyl-3-pentyl-3,4-dihydro-2H-pyrrole (6, resulting from transamination of the ketone), were synthesised. Only 5 a restored pigment production in a strain of Serratia sp. ATCC 39006 blocked earlier in MAP biosynthesis. PigB is membrane-associated and inactive when its transmembrane domain was deleted, but HapB, its homologue in Hahella chejuensis, lacks the transmembrane domain and is active in solution. Two colourimetric assays for PigB and HapB were developed, and the HapB-catalysed reaction was kinetically characterised. Ten analogues of 5 a were synthesised, varying in the C2 and C3 side chains, and tested as substrates of HapB in vitro and for restoration of pigment production in Serratia ΔpigD in vivo. All lengths of side chain tested at C3 were accepted, but only short side chains at C2 were accepted. The knowledge that 5 a is an intermediate in prodigiosin biosynthesis and the ease of synthesis of analogues of 5 a makes a range of prodigiosin analogues readily available by mutasynthesis.