Elemental Analysis Research Articles

Assembly of Fe@Zn-Coordination Polymer Composite: Iron Doping Foster the Luminescent Detection for Tetracycline, Uric Acid and Cr2O72− and Crystal Violet Degradation Efficiency

Coordination polymers exhibit a diverse array of applications across various fields, and through the development of composite materials, their utility and versatility are further enhanced, broadening their impact on our world. In this work We synthesized the first coordination polymer (CP) based on Zn and doped with Fe composites (Fe@Zn-CP Composite), which exhibit enhanced photocatalytic activity triggered by visible light. Using mixed ligands orotic acid potassium salt, 1,3 di (4-pyridyl) propane (dpp), and FeSO4 in a simple method at ambient temperature, the Zn-CP [Zn8(Or)8(dpp)4(H2O)8] was resynthesized here to form the Fe@Zn-CP composites. Zn-CP and Fe@Zn-CP Composite were both characterized by powder X-ray diffraction, FT-IR spectra analysis, and SEM-EDX analysis and elemental mapping analysis. It has been observed that Fe@Zn-CP Composite is as multi-functional luminescence sensor for MnO4−, Cr2O72− and Tetracycline with high sensitivity. In-depth research has also been done on the recyclable nature, and photocatalytic efficiency of Zn-CP and Fe@Zn-CP Composite for the decomposition of organic dyes Crystal Violet and Rose Bengal (RB) in contaminated water under the sunlight irradiation.

Synthesis, Docking Study of Some Novel Chromeno[4',3'-b]Pyrano [6,5-d]Pyrimidine Derivatives Against COVID-19 Main Protease (Mpro) (6LU7, 6M03).

In this work, some new chromeno[4',3'-b]pyrano[6,5-d]pyrimidines,3-amino and 3-methyl-5-aryl-4-imino-5(H)-chromeno[4',3'-b]pyrano[6,5-d]pyrimidine-6-ones derivatives were synthesized. Chromenopyrimidines have attracted significant attention recently because of their activities, such as antiviral and cytotoxic activity. All synthesized compounds were characterized using IR, 1H-NMR, Mass Spectroscopy, and elemental analysis data. Molecular docking studies were carried out to determine the inhibitory action of studied ligands against the Main Protease (6LU7, 6m03) of coronavirus (COVID-19). Moreover, the Lipinski Rule parameters were calculated for the synthesized compounds. The result of the docking studies showed a significant inhibitory action against the Main protease (Mpro) of SARS-CoV-2, and the binding energy (ΔG) values of the ligands against the protein (6LU7, 6M03) are -7.8 to -9.9 Kcal/mole. It may conclude that some ligands were likely to be considered lead-like against the main protease of SARS-CoV-2.

Synthesis of 3-(substitutedthiocarbamide)-aniline derivatives from di-tert-butyl dicarbonate (BoC) protected 3-chloroaniline

Synthesis of substituted thiocarbamide derivatives is important in the fields of medicinal, agricultural, chemical, and pharmaceutical. Thiocarbamides are commonly utilized as starting materials for several organic synthetic processes and have been studied in search for easy and effective methods of chemical synthesis. In the existing research work, 3-chloroaniline was protected by a di-tert-butyl dicarbonate (BoC) protecting agent. Substituted thiocarbamide derivatives were synthesized using condensation of various substituted thioureas with amino group-protected 3-chloroaniline. The structures of all compounds of 3(substitutedthiocarbamido)-aniline were characterized by 1H-NMR, 13C-NMR, FT-IR, LCMS and CHNS elemental analysis.

Biological activity of MgO nanoparticle synthesis by plasma-assisted reduction method

Abstract In the current report, MgO nanoparticles are synthesized by the plasma-assisted reduction method. This method is eco-friendly due to its safety, not use of toxic reducing agents, low cost, and rapid synthesis. Several techniques were employed to determine the crystalline size, particle size, morphology, elemental analysis, and optical properties of the MgO NPs. MgO nanoparticles had a semi-spherical particle structure with diameters ranging from 30.40 to 39.57 nm. The average crystalline size was measured to be 23.7 nm. An analysis using a UV–vis spectrophotometer reveals that the absorbance of MgO nanoparticles results in a significant peak at 354 nm, indicating an energy band gap of 3.2 eV. Subsequent detailed analysis was performed utilizing Rietveld refinement to accurately determine the crystallographic parameters. Additionally, electron density mapping was scrutinized to provide further insights into the atomic arrangement. The antibacterial and antibiofilm activity of MgO NPs was assessed against Klebsiella pneumoniae, Escherichia coli (gram-negative), and Staphylococcus aureus (gram-positive) bacteria at a dose concentration of 10 mg/L. The antibacterial activity (zone of inhibition) and inhibition biofilm rate of MgO NPs against S. aureus were more effective than those of K. peneumoniae and E. coli. Consequently, this investigation demonstrates that the MgO NPs exhibited strong antibacterial properties and exhibited significant potential for the inhibition of pathogenic bacteria.

Atomic Layer Deposition of Nickel Using Ni(dmamb)2 and ZnO Adhesion Layer Without Plasma

In this study, a novel deposition technique that utilizes diethylzinc (C4H10ZnO) with H2O to form a ZnO adhesion layer was proposed. This technique was followed by the deposition of vaporized nickel(II) 1-dimethylamino-2-methyl-2-butoxide (Ni(dmamb)2) and H2 gas to facilitate the deposit of uniform layers of nickel on the ZnO adhesion layer using atomic layer deposition. Deposition temperatures ranged from 220 to 300 °C. Thickness, composition, and crystallographic structure results were analyzed using spectroscopic ellipsometry, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD), respectively. An average growth rate of approximately 0.0105 angstroms per cycle at 260 °C was observed via ellipsometry. Uniform deposition of ZnO with less than 1% of Ni was displayed by utilizing the elemental analysis function via SEM, thereby providing high-quality images. XPS revealed ionizations consistent with nickel and ZnO through the kinetic and binding energies of each detected electron. XRD provided supplemental information regarding the validity of ZnO by exhibiting crystalline attributes, revealing the presence of its hexagonal wurtzite structure.

Enhancing silicon spectral emission in LIBS using Tesla coil discharge

Abstract Laser-induced breakdown spectroscopy (LIBS) is a powerful technique for elemental analysis, offering rapid analysis, minimal sample preparation, wide elemental coverage, and portability. To enhance the detection sensitivity of LIBS, increasing the spectral emission intensity is crucial. This paper explores the use of Tesla coil (TC) discharge as an alternative to spark discharge in silicon LIBS. The study examines the influence of TC discharge on both time-integrated and time-resolved spectra, with and without TC discharge; the corresponding electron temperature and density are obtained. The results show that TC discharge significantly amplifies the spectral intensity, improving signal sensitivity in LIBS analysis. Specifically, in the laser energy range from 7.4 to 24.0 mJ, TC discharge increased the average spectral line intensities of Si (II) 385.60 nm and Si (I) 390.55 nm by factors of 8.4 and 5.1, respectively. Additionally, the average electron temperature and density were enhanced by approximately 3.2% and 4.2%, respectively, under TC discharge. The advantages of TC discharge include higher energy deposition, extended discharge duration, reduced electrode erosion, and enhanced safety. This research contributes to advancing LIBS technology and expanding its applications in various fields.

Metal Complexes of Cobalt Chloride with Vinyl‐, Allyl‐ and Styrylbenzimidazole Ligands: Synthesis, Structure, and Properties

AbstractThree N‐substituted benzimidazole cobalt(II) complexes have been synthesized and fully characterized by elemental analysis, FT‐IR spectroscopy, and X‐ray crystallography. The crystal packing formation features were studied by AIM analysis, and the energy and nature of both weak noncovalent interactions in the crystal and metal–ligand coordination bonds were assessed. These N‐coordinated cobalt(II) complexes were screened for antimicrobial activities against Gram‐negative (Escherichia coli, Bacillus subtilis) and Gram‐positive (Enterococcus durans) bacteria. Minimal inhibitory concentrations (MIC = 6.2 mg/mL) were found for complex cobalt chloride with allylbenzimidazole ligands against E. durans and E. coli. Its antimicrobial activity is several times higher compared to the reference gentamicin. Molecular docking made it possible to consider the nature of binding of cobalt metal complexes with vinyl‐, allyl‐ and styrylbenzimidazole ligands to biological targets and estimate their energy. The binding energy meanings depend on protein and ligand type, and reaches 8 kcal/mol.

Chemical Identification of Purified Molecule (3-Ethyl-6,7-dihydroxy-2- phenyl-chromen-4-one) Prepared from Alpinia officinarum with Anti- Cryptococcus neoformans Potential

Background: Plants contain a large number of molecules with various potentials, including antifungal impact. Cryptococcus neoformans (C. neoformans) is a yeast that causes Cryptococcosis infection in both immunocompromised and normal individuals worldwide. Objective: This study aimed to investigate the inhibitory impact of plant extracts on C. neofor-mans and perform purification of the most bioactive product for further chemical identifica-tion. Methods: The anti-C. neoformans potential of fourteen plants extracted by using various sol-vents, including water, methanol, and benzene, was tested. The most promising compound with anti-C. neoformans was purified. The minimal inhibitory level of the purified sub-frac-tion as compared to fluconazole as a standard drug was determined. The chemical identifica-tion of the purified product was carried out using FTIR, 1HNMR, elemental analysis, and Mass spectroscopy. Results: Alpinia officinarum (A. officinarum) methanolic extract has the highest antifungal impact on C. neoformans and showed an inhibition zone of 3.2±0.2 cm. The methanolic ex-tract was separated into 14 fractions, where the fifth fraction showed the highest activity. It was further separated into four sub-fractions that were tested to characterize the most promis-ing molecule with anti-C. neoformans impact, which was further chemically identified as 3-Ethyl-6,7-dihydroxy-2-phenyl-chromen-4-one. The purified product led to significant altera-tions in the ultra-structure of C. neoformans relative to the standard drug.

Ecology of Trifolium elazizense, an endemic alpine meadow species from Türkiye

This study presents some ecological characteristics of Trifolium elazizense, a local endemic alpine meadow plant species in the East Anatolian region of Türkiye. Elemental analyses were carried out in plants and soils. Soil-plant relationships were evaluated. The results obtained from all plant parts of Trifolium elazizense (root, stem and leaves) showed that the elemental concentrations of boron, calcium, copper, potassium, manganese, lead and zinc were within the limit values; cadmium, iron and magnesium were above the limit values. The general concentration of all elements in the soil samples is generally within acceptable limits.

Cu(II)-tyrosinase enzyme catalyst mediated synthesis of mosquito larvicidal active pyrazolidine-3,5-dione derivatives with molecular docking studies and their ichthyotoxicity analysis

The objective of this study was to develop pyrazolidine-3,5-dione derivatives with potential as environmentally friendly pesticides for pest control, specifically focusing on their efficacy as larvicidal agents. A novel one-pot synthesis of multicomponent pyrazolidine-3,5-dione derivatives (1a-m) was accomplished via the grindstone method using Cu(II)tyrosinase enzyme as a catalyst under mild reaction conditions, yielding 84%–96%. The synthesised derivatives (1a-m) were characterized using various spectroscopic methods (mass spectrometry, elemental analysis, FT-IR, and 1H and 13C NMR). NMR characterisation using DMSO-d6 as a solvent. The larvicidal and antifeedant activities of the synthesised compounds were screened and in silico computational studies were performed. The larvicidal activity against Culex quinquefasciatus and antifeedant activity against Oreochromis mossambicus were evaluated. Among the synthesised compounds, compound 1c demonstrated superior efficacy (LD50: 9.7 μg/mL) against C. quinquefasciatus compared to permethrin (LD50: 17.1 μg/mL). Regarding antifeedant activity, compounds 1a, 1e, 1f, 1j, and 1k exhibited 100% mortality at 100 μg/mL. Molecular docking analysis was performed to assess the binding capacity of a mosquito odorant-binding protein (3OGN) from Culex quinquefasciatus to compound 1c. The results revealed that compound 1c had a docking score of -10.4 kcal/mol, surpassing that of standard permethrin (-9.5 kcal/mol). Furthermore, DFT calculations were conducted to acquire theoretical data aligned with the experimental FT-IR results. According to experimental research, compound 1c demonstrates promising larvicidal activity against mosquito larvae of C. quinquefasciatus.

Mononuclear and multinuclear O^N^O‐donor Zn(II) complexes as robust catalysts for the production and depolymerization of poly(lactide)

Mononuclear and multinuclear O^N^O‐donor Zn(II) complexes are herein reported as catalysts in the ring‐opening polymerization (ROP) of rac‐lactide (rac‐LA) and depolymerization of poly(lactide) (PLA). Reactions of imino‐phenol proligand 2[((2‐hydroxyethyl)imino)methyl]phenol (L1H2) with ZnCl2 and ZnEt2 afforded the dinuclear and tetranuclear complexes [Zn2(L1H)2Cl2] (Zn1) and [Zn4(L1)4] (Zn2), respectively. Separately, treatments of proligands 2‐[1‐((2‐hydroxyethyl)imino)ethyl]phenol (L2H2) and [((2‐methoxyethyl)imino)methyl]phenol (L3H) with ZnCl2 gave the respective mononuclear complexes [Zn(L2H2)2Cl2] (Zn3) and [Zn(L3H)2Cl2] (Zn4), while the reactions of L3H with ZnEt2 afforded the bis(chelated) mononuclear complex [Zn(L3)2] (Zn5). The complexes were characterized using NMR and IR spectroscopy, elemental analysis and single crystal X‐ray crystallography. All the Zn(II) complexes showed high catalytic activities in the ROP of rac‐LA (kapp of up to 4.18 × 10‐4 s‐1) to give moderate molecular weight PLA (39 960 g mol‑1) with relatively narrow dispersities (Đ = 1.4‐2.1). The complexes produced mainly atactic PLAs with Pr values of 0.51‐0.58. More significantly, complexes Zn1, Zn2 and Zn5 were also active in the depolymerization of commercial PLA in methanol (kapp of up to 2.67 × 10‐4 s‐1) to produce alkyl lactates. The ROP and depolymerization behavior were largely controlled by the structure and nuclearity of the complexes.

Synthesis, Structure, and Light Absorption of Octanoyl Amino Acids

Amino acid lanthanide complexes are a promising class of environmentally friendly and non-toxic optical organic materials that find extensive applications in biomedicine, molecular probes, and optical devices. In this study, three amino acid lanthanide complexes, octanoyl glycine gadolinium (Gd(oct-ala)3×H2O), octanoyl serine gadolinium (Gd(oct-ser)3×H2O), and octanoyl phenylalanine gadolinium (Gd(oct-phe)3×H2O), were synthesized by reacting octanoyl amino acid ligands with gadolinium chloride. The coordination structure of the gadolinium complexes was determined by elemental analysis and infrared spectroscopy. XRD and polarized light microscopy confirmed the amorphous structure of the complexes. DSC and TG-DTA were used to investigate the thermodynamic stability of the gadolinium complexes, and their solubility and UV-visible light absorption properties were also evaluated. Our results demonstrate that all three gadolinium complexes exhibit excellent UV-visible light absorption performance, with the Gd(oct-phe)3×H2O containing a phenyl ring showing the highest light absorption efficiency.

Exploring and evaluating the relationship between Saccharomyces cerevisiae biofilm maturation on carbon felt anodes and microbial fuel cell performance

Microbial fuel cells (MFCs) hold great promise as sustainable bioenergy sources, with their performance intricately linked to the formation and characteristics of biofilms. This study delves into the bio-electrochemical perspective of biofilms in MFCs, aiming to elucidate their pivotal role in MFC functionality. The investigation focused on a yeast-based MFC operated through 48 h per cycle, with cycle 5 marking the maturation stage of biofilm formation. During this phase, voltage stability was observed, with a stationary phase voltage of 38.9±2.6 mV. Notably, cycle 5 exhibited a significant boost in power density, reaching 8.82 mW m-2, accom­panied by the lowest internal resistance of 100 Ω. Furthermore, the electron transfer rate constant from cycle 5 is 1.14±0.02 s-1, 57 times higher than the initial, underscoring biofilm's catalytic potential. Additionally, cyclic voltammetry unveiled non-linear relationships between redox reaction peak current and scan rate, with a consistent DEp of ~219 mV at 100 mV s-1. Importantly, elemental analysis disclosed incorporating diverse elements (Na, Al, Si, P, S, Cl, K, Ca, Cr, and Fe) into the carbon felt, signifying their association with biofilm development. These findings offer critical insights into optimizing MFC performance through biofilm modulation, advancing sustainable bioenergy technologies.

Crystal Structure, Photophysical Properties and Antibacterial Activity of a Cd(II) Complex with Trans-2,3,4-Trimethoxycinnamic Acid and 4,4′-Bipyridine Ligands

A new coordination polymer {[Cd(C12H13O5)2(4,4′-bpy)(H2O)2]}n (Cd-Tmca-bpy) was constructed with trans-2,3,4-Trimethoxycinnamic acid (HTmca) and 4,4′-Bipyridine (4,4′-bpy) ligands. This complex was structurally characterized on the basis of elemental analysis, infrared (IR) spectroscopy, powder X-ray diffraction and thermogravimetric analyses. X-ray crystallography revealed that the complex was monoclinic, space group C2/c. The Cd(II) ion in the complex was six coordinated, adopting an octahedron geometry. The neighboring Cd(II) ions linked linear ligand 4,4′-bpy molecules to form an infinite 1D chain. The 1D chain was further interlinked by O–H···O and C–H···O hydrogen bonds, resulting in a 3-D supramolecular framework. Meanwhile, the photoluminescence spectrum of the Cd(II) complex at room temperature exhibited an emission maximum at 475 nm. Using the time-dependent density functional theory (TD-DFT) method, the electronic absorption spectra of the Cd(II) complex was predicted. A good agreement was achieved between the predicted spectra and the experimental data. Bioactivity studies showed that the complex exhibited significant inhibition halos against Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus).

Microwave and ultrasound-assisted green protocols for 5-methylthiazole induced Betti bases: molecular docking, in-silico pharmacokinetics, and anticancer activity studies

ABSTRACT Herein, we describe an efficient one-pot three-component microwave and ultrasound-endorsed approaches for synthesizing distinct 5-methylthiazole induced Betti bases (5-methyl-thiazol-2-ylamino-aryl-benzylnapthols) employing silica sulfuric acid (SSA, silica-OSO3H) as an active heterogeneous acid catalyst. The title compounds produced in good yields (86–95%) from naphthalen-2-ol, 5-methylthiazol-2-amine, and assorted aryl aldehydes; and structurally characterized by spectral and elemental analyses. A comprehensive comparative study of conventional, ultrasonic, and microwave-irradiated synthetic routes has been achieved by optimizing various reaction parameters. These new protocols provide several advantages, including the use of an inexpensive, non-toxic, and reusable catalyst. Additionally, they benefit from mild reaction conditions, short reaction times, and simple workup and purification procedures, thereby increasing their practicality. Furthermore, the synthesized compounds were evaluated for their anticancer potency against A-549 (lung cancer) and A-498 (kidney cancer) cell lines, with scaffold IVa demonstrating excellent (GI50 < 10 µg/mL) inhibitory activity against A-549. Additionally, molecular docking was performed to investigate potential binding interactions between ligands and proteins. Scaffold IVa exhibited the best docking with cancerous target proteins 1M17 (−8.9 kcal/mol) and 1M14 (−7.2 kcal/mol), thereby supporting our bio-activity studies.

Temperature dependent self-assembly of lanthanide coordination polymers based on a benzimidazolium dicarboxylate linker: synthesis, structure and luminescence properties

Five new coordination polymers, namely [Ln(L)(NO3)2]n (Ln = La (1), Pr (2) and Sm (3)), [Eu(L)(NO3)2·1.5H2O]n (4) and [Tb(L)(OAc)2(H2O)·3H2O]n (5) (HOAc = CH3COOH), were synthesised by reaction of lanthanide nitrates with 1,3-bis(4-carboxybenzyl)benzimidazolium chloride (H2L+Cl−) under solvothermal conditions. All the coordination polymers were characterised by powder X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, elemental analysis and single crystal X-ray diffraction. Complexes 1–5 exhibit two different 2-D structures due to the variation in reaction temperature. Complexes 1–4 are isostructural and crystallised in the monoclinic system, C2/c space group, showing a two-dimensional layer with Ln chains linked by L− ligands. Complex 5 crystallised in the P21/n space group, featuring a 2-D layer different from 1–4 with Tb dimers linked by L− ligands through carboxylates. Further, the luminescence properties of complexes 3–5 were investigated. In addition, the fluorescence lifetime and quantum efficiency of complex 4 were measured.

Studying the Characteristics of Tank Oil Sludge

Oil sludge is one of the main pollutants generated by the oil industry. Due to serious pollution and increasing oil production, problems arise every year in the effective treatment of oil sludge. The current study examines the composition and physicochemical characteristics of oil sludge, as well as traditional and new methods for processing oil sludge. With the tightening of environmental protection requirements, oil sludge quality reduction, recycling, and harmless treatment technologies will become necessary in the future. The primary task was to determine the composition of tank oil sludge, separate it from mechanical impurities, and study the influence of ultrasonic treatment and subsequent atmospheric distillation on the extract. The separation of the concentrate and the composition of the tank oil sludge, using an extracted mixture of hexane and benzene, are considered. The use of modern SEM methods, elemental analysis, NMR analysis, IR, ultrasound, and GC–mass spectrometry made it possible to characterize the organic part of reservoir oil sludge and its distillation products. First, 300 g of tank oil sludge was preheated and mixed with 300 mL of solvent (hexane:benzene = 1:1). After mixing with the solvent, the result mixture was filtered. Then, it was placed in an ultrasonic bath and exposed to ultrasound at a frequency of 100 kHz for 30 min. After processing, it was extracted in a Soxhlet apparatus at a temperature of 65 °C to isolate the extract. The resulting extract was analyzed on a gas chromatograph with mass detection. The composition of the extract was as follows (in %): hexane—83.99; total hydrocarbon isomers—7.12; n-hydrocarbons—2.52; benzene—6.37%. At a temperature of 85 °C, the benzene yield was 65.85%. It has been established that the fractions obtained through the distillation of oil sludge at temperatures of 65–85 °C have improved dissolving capacity. It has also been shown that the use of these fractions promotes an increase in the content of hydrocarbon isomers by 12–13% in the extract composition.

Polynitro-1,2,4-triazole Energetic Materials with N-Amino Functionalization.

Trinitromethyl and N-amino groups were innovatively incorporated into the framework of 1,2,4-triazole, resulting in 1-amino-5-nitro-3-(trinitromethyl)-1,2,4-triazole (2). Ammonium and hydrazinium salts of 1-amino-5-nitro-3-(dinitromethyl)-1,2,4-triazole were synthesized by acidification, extraction, and neutralization with bases from the potassium salt. All of the newly prepared energetic compounds were comprehensively characterized by using infrared spectroscopy, elemental analysis, nuclear magnetic resonance spectroscopy, and single crystal X-ray diffraction. Compound 2 exhibits favorable properties such as positive oxygen balance (OBCO2 = 5.8%), high density (1.88 g cm-1), good detonation performances (vD = 8937 m s-1, P = 35.5 GPa), and appropriate friction sensitivity (FS = 144 N). The potassium salt 3 demonstrates good thermal decomposition temperature (181 °C) and high density (1.98 g cm-1), while the ammonium salt and hydrazinium salt also display good thermal decomposition temperatures of 183 and 176 °C, respectively. Among these compounds, the ammonium salt exhibits the lowest mechanical sensitivities (FS = 144 N, IS = 6 J).

Metal complexes containing vitamin B6-based scaffold as potential DNA/BSA-binding agents inducing apoptosis in hepatocarcinoma (HepG2) cells.

A ligand (HL) was synthesized from the pyridoxal hydrochloride (vitamin B6 form) and 1-(2-Aminoethyl)piperidine in one single step. The metal complexes [Zn(L)(Bpy)]NO3 (1), [Cu(L)(Bpy)]NO3 (2), and [Co(L)(Bpy)]NO3 (3) were prepared by tethering HL and 2,2'-bipyridine. The synthesized HL and metal complexes 1-3 were thoroughly characterized using spectroscopic techniques such as 1H NMR, 13C NMR, FTIR, EI-MS, molar conductance, and magnetic moment, in addition to CHN elemental analysis. The geometry of complexes was square pyramidal around the metal ions {Zn(II), Cu(II), and Co(II)}. The interaction of ligand and metal complexes with DNA and BSA macromolecules was accomplished by UV-Vis absorption and fluorescence spectroscopy in vitro. The hyperchromism in band at 303-325 with no shift supports the groove binding with some partial intercalation in grooves. Similarly, in BSA-binding studies, complex 2 shows greater binding potential in the hydrophobic core probably near the Trp-212 in the subdomain IIA. Furthermore, complex 2 shows excellent cytotoxicity on HepG2 cancer cells with IC50 = 25.0 ± 0.45µM. The detailed analysis by cell-cycle studies shows cell arrest at the G2/M phase. The type of cell death was authenticated by an annexin V-FTIC dual staining experiment that reveals maximum death by apoptosis together with non-specific necrosis.

Changes in growth, lanthanide binding, and gene expression in Pseudomonas alloputida KT2440 in response to light and heavy lanthanides.

Pseudomonas alloputida KT2440 is a ubiquitous, soil-dwelling bacterium that metabolizes recalcitrant and volatile carbon sources. The latter is utilized by two redundant, Ca- and lanthanide (Ln)-dependent, pyrroloquinoline quinone-dependent alcohol dehydrogenases (PQQ ADH), PedE and PedH, whose expression is regulated by Ln availability. P. alloputida KT2440 is the best-studied non-methylotroph in the context of Ln-utilization. Combined with microfluidic cultivation and single-cell elemental analysis, we studied the impact of light and heavy Ln on transcriptome-wide gene expression when growing P. alloputida KT2440 with 2-phenylethanol as the carbon and energy source. Light Ln (La, Ce, and Nd) and a mixture of light and heavy Ln (La, Ce, Nd, Dy, Ho, Er, and Yb) had a positive effect on growth, whereas supplementation with heavy Ln (Dy, Ho, Er, and Yb) exerted fitness costs. These were likely a consequence of mismetallation and non-utilizable Ln interfering with Ln sensing and signaling. The measured amounts of cell-associated Ln varied between elements. Gene expression analysis suggested that the Ln sensing and signaling machinery, the two-component system PedS2R2 and PedH, responds differently to (non-)utilizable Ln. We expanded our understanding of the lanthanide (Ln) switch in P. alloputida KT2440, demonstrating that it adjusts the levels of pedE and pedH transcripts based on the availability of Ln. We propose that the usability of Ln influences the bacterium's response to different Ln elements.IMPORTANCEThe Ln switch, the inverse regulation of Ca- and Ln-dependent PQQ ADH in response to Ln availability in organisms featuring both, is central to our understanding of Ln utilization. Although the preference of bacteria for light Ln is well known, the effect of different Ln, light and heavy, on growth and gene expression has rarely been studied. We provide evidence for a fine-tuning mechanism of Ca- and Ln-dependent PQQ ADH in P. alloputida KT2440 on the transcriptome level. The response to (non-)utilizable Ln differs depending on the element. Ln commonly co-occur in nature. Our findings underline that Ln-utilizing microbes must be able to discriminate between Ln to use them effectively. Considering the prevalence of Ln-dependent proteins in many microbial taxa, more work addressing Ln sensing and signaling is needed. Ln availability likely necessitates different adaptations regarding Ln utilization.