Theophylline as a quorum sensing and biofilm inhibitor in Pseudomonas aeruginosa and Chromobacterium violaceum

Quorum sensing (QS) is pivotal in coordinating virulence factors and biofilm formation in various pathogenic bacteria, making it a prime target for disrupting bacterial communication. Pseudomonas aeruginosa is a member of the "ESKAPE" group of bacterial pathogens known for their association with antimicrobial resistance and biofilm formation. The current antibiotic arsenal falls short of addressing biofilm-related infections effectively, highlighting the urgent need for novel therapeutic agents. In this study, we explored the anti-QS and anti-biofilm properties of theophylline against two significant pathogens, Chromobacterium violaceum and P. aeruginosa. The production of violacein, pyocyanin, rhamnolipid, and protease was carried out, along with the evaluation of biofilm formation through methods including crystal violet staining, triphenyl tetrazolium chloride assay, and fluorescence microscopy. Furthermore, computational analyses were conducted to predict the targets of theophylline in the QS pathways of P. aeruginosa and C. violaceum. Our study demonstrated that theophylline effectively inhibits QS activity and biofilm formation in C. violaceum and P. aeruginosa. In P. aeruginosa, theophylline inhibited the production of key virulence factors, including pyocyanin, rhamnolipid, protease, and biofilm formation. The computational analyses suggest that theophylline exhibits robust binding affinity to CviR in C. violaceum and RhlR in P. aeruginosa, key participants in the QS-mediated biofilm pathways. Furthermore, theophylline also displays promising interactions with LasR and QscR in P. aeruginosa. Our study highlights theophylline as a versatile anti-QS agent and offers a promising avenue for future research to develop novel therapeutic strategies against biofilm-associated infections.

Antibiofilm potential of gallic acid against Klebsiella pneumoniae and Enterobacter hormaechei: in-vitro and in-silico analysis

Biofilm refers to a community of microorganisms that adhere to a substrate and play a crucial role in microbial pathogenesis and developing infections associated with medical devices. Enterobacter hormaechei and Klebsiella pneumoniae are classified as significant nosocomial pathogens within the ESKAPE category and cause diverse infections. In addition to their reputation as prolific biofilm formers, these pathogens are increasingly becoming drug-resistant and pose a substantial threat to the healthcare setting. Due to the inherent resistance of biofilms to conventional therapies, novel strategies are imperative for effectively controlling E. hormaechei and K. pneumoniae biofilms. This study aimed to assess the anti-biofilm activity of gallic acid (GA) against E. hormaechei and K. pneumoniae. The results of biofilm quantification assays demonstrated that GA exhibited significant antibiofilm activity against E. hormaechei and K. pneumoniae at concentrations of 4 mg mL-1, 2 mg mL-1, 1 mg mL-1, and 0.5 mg mL-1. Similarly, GA exhibited a dose-dependent reduction in violacein production, a QS-regulated purple pigment, indicating its ability to suppress violacein production and disrupt QS mechanisms in Chromobacterium violaceum. Additionally, computational tools were utilized to identify the potential target involved in the biofilm formation pathway. The computational analysis further indicated the strong binding affinity of GA to essential biofilm regulators, MrkH and LuxS, suggesting its potential in targeting the c-di-GMP and quorum sensing (QS) pathways to hinder biofilm formation in K. pneumoniae. These compelling findings strongly advocate GA as a promising drug candidate against biofilm-associated infections caused by E. hormaechei and K. pneumoniae.

Insights on the structural characteristics and molecular dynamic studies of methyl vanillin Schiff base bio-compounds

A new crystalline form of Schiff base, N-cyclohexyl-1-(3,4-dimethoxyphenyl)methanimine (CHADMB) was obtained from methanolic solution of cylohexylamine and (methylvanillin) 3,4dimethoxybenzaldehyde. Single crystal X-ray diffraction study reveals that the compound crystallized in monoclinic crystal system with P21/c space group having four molecules per unit cell (Z = 4). Hirshfeld surface (HS) analysis and 2D fingerprint plots reveals that weak non-covalent interactions are responsible for crystal packing. The UV-Vis spectroscopy study reveals that the optical band gap of the compound is 4.25 eV. The dielectric properties were studied as a function of frequency at room temperature and the results show that these properties can be exploited for optoelectronic applications. Thermal stability of the compound is revealed by thermogravimetric and differential thermogravimetric analysis. The in vitro antimicrobial activity against Gram negative (E. coli and P. aeruginosa and Gram positive (S. aureus ) bacterial strains and two fungal strains (C. albicans and A. niger) were studied by agar well diffusion method. It is found that the Schiff base is inhibiting the growth of the tested species to varying degrees. Molecular docking studies indicate that alkyl-pi and pi-pi weak interactions enhance the binding affinity of Schiff base-protein complexes. Molecular dynamics study reveals interaction of CHADMB complexed with bacterial protein, EC showed maximum stability which is in agreement with experimental result.Communicated by Ramaswamy H. Sarma.

Ethyl Gallate: Promising Cytoprotective against HIV-1-Induced Cytopathy and Antiretroviral-Induced Cytotoxicity

Introduction

HIV-1 infection in cell culture is typically characterized by certain cytopathic effects such as vacuolization of cells and development of syncytia, which further lead to cell death. In addition, the majority of drugs during HIV treatment exhibit serious adverse effects in patients, apart from their beneficial role. During the screening of cytoprotective agents to protect the cells from HIV-1-associated cell death and also drug-associated toxicity, antioxidants from a natural source are assumed to be a choice. A well-known antioxidant, ethyl gallate (EG), was selected for cytoprotection studies which have already been proven as an anti-HIV agent.

Objective

The main objective of the study was to explore the cytoprotective potential of EG against HIV-1-induced cytopathic effect and antiretroviral drug toxicity.

Methods

DPPH free radical scavenging assay was performed with EG to find the effective concentration for antioxidant activity. HIV-1infection-associated cytopathic effects and further rescue by EG were studied in MT-2 lymphocytes by the microscopic method and XTT cytopathic assays. The cellular toxicity of different antiretroviral drugs in different cell lines and the consequent cytoprotective effectiveness of EG were investigated using an MTT cell viability assay.

Results

Like ascorbic acid, EG exhibited promising antioxidant activity. HIV-1 infection of MT2 cells induces cell death often referred to as the cytopathic effect. In addition, the usage of antiretroviral drugs also causes severe adverse effects like cytotoxicity. In this context, EG was tested for its cytoprotective properties against HIV-1-induced cytopathic effect and drug-mediated cellular toxicity. EG reclaimed back the MT2 cells from HIV-1-induced cell death. Antiretroviral drugs, such as ritonavir, efavirinz, AZT, and nevirapine, were tested for their toxicity and induced more cell death at higher concentrations in different tissue models such as the liver (THLE-3), lung (AEpiCM), colorectal (HT-29), and brain (U87 MG). Pretreated cells with EG were rescued from the toxic doses of ART.

Conclusion

EG was found to be exhibited cytoprotection not only from HIV-1-linked cell death but also from the chemotoxicity of antiretroviral drugs. Evidently, EG could be a cytoprotective supplement in the management of AIDS along with its enormous antioxidant benefits.

The Study of Filamentous Fungi in Potable Water and Its Biofilm Formation in Water Pipeline System

Water is essential for life and it is an inorganic constituent of living matter. Water pipeline systems are sighted as problematic in aquatic habitats in which multiple pathogens are occupied including fungi. They have rigid cell walls containing glucans and chitin. The bodies of fungi comprise filaments called hyphae. These hyphae are split into a mat of interwoven single cells made of mycelium. Fungi can pollute the drinking water system and are responsible for biofilm formation. Biofilms are complex polymers containing many times their dry weight in water. Moisture is essential for biofilm formation. The occurrence of biofilms affects the quality of drinking water. Hence, the present study is aimed at recovering the fungi from drinking water samples and their biofilm formation in the water pipeline system. Drinking water samples such as mineral water, tap water, and RO-purified water are collected from different places. Fungi such as Aspergillus, Penicillium and Mucor were recovered from these samples and most species belong to Aspergillus and Penicillium. Further, the biofilm formation of fungi from cast iron in the pipeline system was detected using fluorescence microscopy and fluorescent in situ hybridization analysis.

A Feasible Multimodal Photoacoustic Imaging Approach for Evaluating the Clinical Symptoms of Inflammatory Arthritis

Numerous traditional medical imaging methods, including computed tomography with X-rays, positron emission tomography (PET), and magnetic resonance imaging (MRI), are utilized frequently in medical settings to screen for illnesses, diagnose patients, and track the effectiveness of treatments. When examining bone protrusions, CT is preferred over MRI for scanning connective tissue. Although the picture quality of PET is inferior to that of CT and MR, it is outstanding for detecting the molecular markers and metabolic functions of illnesses. To give high-resolution structural pictures and improved ailment sensitivity and specificity within another image, multimodal data and substantial therapeutic influence on advanced diagnostics and therapeutics have been used. The goal was to evaluate the clinical significance of multimodal photoacoustic/ultrasound (PA/US) articular imaging scoring, a cutting-edge image technique that may show the microvessels and oxygen levels of rheumatoid arthritis-related inflamed joints (RA). The PA/US imaging technology analyzed seven tiny joints. The PA and power Doppler (PD) impulses were semiquantified using a 0-3 grading scale, and the averages of the PA and PD scores for the seven joints are computed. Three PA+SO2 types were found determined by the relative oxygen levels (SO2) measurements of the affected joints. Researchers evaluated the relationships between the disease activity ratings and the PA/US imaging ratings. The PA scores and medical ratings that reflect the extent of the pain have strong relationships with each other, as do the PA+SO2 combinations. PA may be clinically useful in assessing RA. Thus, the research evaluated the clinical symptoms of inflammatory arthritis using a multimodal photoacoustic image process.

Efficient photocatalytic degradation of industrial contaminants by Piper longum mediated ZnO nanoparticles

Piper longum extract as a reducing agent in green synthesis method is used to synthesize ZnO nanoparticles (ZnO-NPs). The impact of the reductant on the structural, optical and surface morphological properties of ZnO-NPs can be analyzed. Piper longum extract has delicately tuned the band gap of ZnO-NPs. Increase in energy band gap indicates an increase in the number of capping molecules in the prepared ZnO nanoparticles. The carbohydrates and proteins not only play a fundamental role in ZnO capping, which is important for its stability, determination and biocompatibility. Thus obtained nanosized ZnO particles are confirmed by the surface morphological studies. Because of various surface interface properties might have different physical-chemical, desorption-adsorption abilities in the direction towards microbes, create different antibacterial performances. S.aureus has maximum inhibition zone of 23 mm and Escherichia coli has minimum inhibition zone of 7 mm. To assess the photocatalytic activity of the prepared ZnO-NPs under UV light irradiation, methyl orange, malachite green and methylene blue dyes were utilized as model contaminants. The degradation efficiency of MG, MB and MO dyes solution is found that 96%, 69% and 48% of degradation efficiency respectively under ultraviolet light irradiation. The properties of synthetic nanopowders suggest that they have important potential for a variety of biochemical and environmental applications.

Microwave assisted hydrothermally synthesized cobalt doped zinc ferrites nanoparticles for the degradation of organic dyes and antimicrobial applications

A novel photocatalyst based cobalt doped zinc ferrites nanoparticles (Co-ZnFe₂O₄ NPs) was prepared to actively concentrate degradation of organic dyes in water. The aim this study is to investigate the effect of substitution of Co²⁺ for Zn²⁺ in zinc ferrites nanoparticles and is characterized with UV-visible spectroscopy, XRD, TEM, SEM, Photoluminescence and Vibrating sample magnetometer technique. When the calcinations temperature increases from 150 °C to 450 °C the amorphous ferrites begins to vanish and the characteristic reflections of cubic spinal Co-ZnFe₂O₄ phase are only observed at 450 °C. The band gap energy (E_g) of sample calcined at 250 °C is calculated at 5.2 eV and that of 450 °C is 4.5 eV. The observed value of band gap energy decreased with increasing calcinations temperature in the samples. The increase in PL peak intensity is due to collective emissions and light-scattering. The doping material, cobalt substitution at spinel zinc ferrites surface, and hence gradually decrease the amorphous effect, increase the saturation magnetization and decrease the coercivity while increasing the temperature. The compounds calcined at 250 °C and 450 °C were investigated for their in vitro antimicrobial activity against Staphylococcus aureus. A sample with 450 °C calcination temperature leads to higher efficiencies in the inhibition of growth of bacteria and degradation of organic dyes. Hence, this study provides a novel photocatalyst of Co-ZnFe₂O₄ NPs in the tile to degrade and analyze the environmentally ignored organic compounds.

Improved photocatalytic activity for degradation of textile dyeing waste water and thiazine dyes using PbWO4 nanoparticles synthesized by co-precipitation method

The coloured dyes released from the textile industrial effluents into water resources cause non-aesthetic pollution and aquatic life toxicity. Thus textile waste water treatment has been studied globally for many years. Photocatalytic properties of lead tungstate (PbWO₄) nanoparticles (NPs) were analyzed for thiazine dyes and textile waste water under ultraviolet light conditions. XRD result showed the tetragonal scheelite structure of PbWO₄ NPs. The crystallinity of the sample was confirmed from the SAED and XRD pattern. The existence of stretch vibration of Pb-O and O-W-O confirmed from FTIR results. EDAX displays optical absorption signals of Pb, W and O, and confirm the formation of PbWO₄. Optical studies reveal that the band gap of the obtained nanoparticles increases with respect to their bulk counterparts that may be attributed to reduction in particle size. TEM images of PbWO₄ powder consists of hexagonal particles and relatively uniform and smooth surface rod shaped prism-like structures. The photocatalytic activity of the prepared nanoparticles was analyzed through the degradation of textile waste water under UV light irradiation. The photocatalytic reaction rate constant was found to be 0.014/min. The small sized PbWO₄ particles can adsorb more OH groups and oxidatively degrade the pollutants in the textile waste water.

A tool to identify potential primary care presentations in the hospital emergency department

Background

Access to primary care has an impact on health outcomes and is a significant public health issue. Limited access to primary care has seen non-urgent presentations to hospital emergency departments continue to rise globally. A lack of a universal workable definition of what a primary care presentation is has impeded national and international estimations of the true burden. Our aim was to develop a standardised code frame to identify potential primary care patients in the emergency department to allow accurate data estimations to be made, and help inform future interventions.

Methods

An audit of medical records was conducted in two major hospitals in Sydney, Australia. A code frame was developed, tested and applied retrospectively to five years of data.

Results

Of 601,168 presentations to the emergency department, 171,906 (29%) were deemed to be potential primary care presentations. The code frame had a sensitivity of 99.9% and a specificity of 49.0%.

Conclusions

This standardised code frame enables accurate retrospective local and national data estimations of the impact of primary care presentations in the emergency department, which was previously not available. The code frame could be used prospectively to evaluate interventions such as diverting patients to primary care settings, and to identify populations for specifically targeted interventions. The conservative nature of the code frame ensures that only those that can safely receive care in a primary care setting are identified as potential primary care.

Key messages

This robust tool will enable more accurate data estimations of primary care appropriate presentations in the emergency department, which can assist planning and policy efforts. It can be easily adapted to incorporate triage codes in international settings and provides a useful tool for comparing international trends.

Purification of Matrixins from Marine Cephalopod

Matrixins play a major role in tissue regeneration and also in various patho-physiological processes. Discovery of matrix metallo proteins (MMPs) and their detailed structural and functional analysis would lead to the development of numerous potent synthetic inhibitors of matrixins to treat certain diseases. In the present investigation, a marine cephalopod- Octopus sp. collected from Cochin, in the south western Indian Ocean was used as animal model for purification of matrixins. The measurements, count, indices and other morphometric characters were noted down before assessing the presence of matrixins in the crude extract of Octopus samples. Purification of matrixins was carried out employing gel filtration chromatography and the purified matrixins was confirmed by gelatin zymogram. The purity of the protein was checked by both native and SDS-PAGE. The studies have provided clear indications of production of MMPs or matrixins with gelatinolytic activity in Octopus sp.

Correlating pulmonary embolism severity with short term mortality to risk stratify for outpatient management

AIMS

We ascertain less than 7-day mortality data in suspected pulmonary embolism (PE) in order to risk stratify patients suitable for outpatient imaging.

METHODS

Retrospective identification of patients presenting to two emergency departments over a two-year period, with a radiologically confirmed PE. PESI and sPESI scores correlated with death at 1, 3, 7, 30 and 90 days.

RESULTS

There was significant correlation between all PESI risk classes and death at 3, 7, 30 and 90 days (p<0.01), but not day 1. No deaths occurred within 1 and 3 days in low risk PESI groups or within 90 days in the low risk sPESI.

CONCLUSION

PESI/sPESI could be reliably utilized to risk stratify patients being considered for outpatient investigation of PE.

Europium-Doped Hydroxyapatite Nanorods: Influence of Silver Doping

In this work, we report the influence of silver nanoparticles of different size on the optical behavior of the europium-doped hydroxyapatite nanorods. The presence of ionic, plasmonically visible and silent (ultra-small) silver nanoparticles on the surface of europium-doped apatite and its influence on its luminescent behavior were discussed. It was found that ionic silver exhibited a concentration-dependent enhancement in emission at the excitation of europium. For plasmonically visible and silent silver nanoparticles, the emission observed was due to the contribution of the ligand passivating the europium-doped hydroxyapatite nanoparticle surface. These nanoparticles due to its luminescent and biocompatible nature can be used for bioimaging applications.

Curcumin-galactomannoside complex inhibits pathogenesis in Ox-LDL-challenged human peripheral blood mononuclear cells

Oxidised low-density lipoprotein (ox-LDL) is a pro-atherogenic molecule, which induces inflammatory response and contributes to the pathogenesis of vascular dysfunction to atherosclerosis. The aim of the present study was to explore the anti-inflammatory effect of a novel bioavailable formulation of curcumin as 'curcumagalactomannosides' (CGM) against ox-LDL-induced inflammatory responses in human peripheral blood mononuclear cells (hPBMCs). Curcumagalactomannosides was made from natural curcumin using the soluble dietary fibre (galactomannans) derived from fenugreek seeds (Trigonella foenumgracum) and the hPBMCs were isolated from healthy human volunteers. The cells were cultured in collagen-coated plates at 37 °C and grouped as Group I (Control), Group II (ox-LDL treated) and Group III (ox-LDL + CGM treated). Further analysis of inflammatory markers, reactive oxygen species and mRNA expression levels indicated significantly increased expressions of iNOS, TNF-α, IL-6 and VCAM-1 in ox-LDL-treated group along with the nuclear translocation of NF-κB. Other inflammatory markers such as LOX, PGE2, total COX and lipid peroxidation level were also found to be significantly (p < 0.05) increased upon ox-LDL treatment. The treatment with CGM on the other hand was found to down-regulate and reverse the ox-LDL-induced alterations indicating its potential anti-inflammatory effect on hPBMCs via. NF-κB signalling pathway.

An overview of Zn-catalyzed enantioselective aldol type C–C bond formation

Enantioselective zinc-catalyzed aldol reactions provide an efficient route for the construction of a wide range of carbon–carbon bond-formation, which are described here.

Effect of age and myocardial infarction on serum and heart lactic dehydrogenase

The effect of isoproterenol (ISO) on the activity of lactic dehydrogenase (LDH) in the serum and heart was investigated in rats belonging to four different age groups. Serum LDH activity increased in all the ages as a result of ISO injection, however, the magnitude and response varied with age. Younger animals were able to recover from the toxicity of ISO much quicker compared to the older ones. An elevation in the LDH enzyme activity in the serum correlated with a decrease in the activity of cardiac muscle LDH in all the age groups of isoproterenol-treated rats.