Cerium oxide and iron oxide nanoparticles abolish the antibacterial activity of ciprofloxacin against gram positive and gram negative biofilm bacteria

Metal oxide nanoparticles have been suggested as good candidates for the development of antibacterial agents. Cerium oxide (CeO₂) and iron oxide (Fe₂O₃) nanoparticles have been utilized in a number of biomedical applications. Here, the antibacterial activity of CeO₂ and Fe₂O₃ nanoparticles were evaluated on a panel of gram positive and gram negative bacteria in both the planktonic and biofilm cultures. Additionally, the effect of combining CeO₂ and Fe₂O₃ nanoparticles with the broad spectrum antibiotic ciprofloxacin on tested bacteria was investigated. Thus, minimum inhibitory concentrations (MICs) of CeO₂ and Fe₂O₃ nanoparticles that are required to inhibit bacterial planktonic growth and bacterial biofilm, were evaluated, and were compared to the MICs of the broad spectrum antibiotic ciprofloxacin alone or in the presence of CeO₂ and Fe₂O₃ nanoparticles. Results of this study show that both CeO₂ and Fe₂O₃ nanoparticles fail to inhibit bacterial growth and biofilm biomass for all the bacterial strains tested. Moreover, adding CeO₂ or Fe₂O₃ nanoparticles to the broad spectrum antibiotic ciprofloxacin almost abolished its antibacterial activity. Results of this study suggest that CeO₂ and Fe₂O₃ nanoparticles are not good candidates as antibacterial agents, and they could interfere with the activity of important antibiotics.     

Improved degradation of lignocellulosic biomass pretreated by Fenton-like reaction using Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> magnetic nanoparticles

The ability of Fe₃O₄ Fenton-like reaction to produce glucose from lignocellulosic biomass was investigated. Fe₃O₄ magnetite nanoparticles were chemically synthesized from iron salts (a mixture of 1 M FeCl₂ and 2M FeCl₃) using an ammonia solution (30% NH₄OH). The synthesized Fe₃O₄ nanoparticles were further characterized by X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy, scanning electron microscopy, and transmission electron microscopy. Reed stems and rice straw biomasses pretreated with optimized Fenton-like reagents (Fe₃O₄ and H₂O₂) increased glucose production by 177 and 87%, respectively, compared to the control without the catalysts.     

Synthesis and reactivities of binuclear iron(III) complexes with ligands composed of two tridentate chelating groups

Several new binuclear iron(III) complexes were prepared using the binucleating ligands in which two molecules of N,N-bis(2-benzimidazolymethyl)amine are linked by a polyatomic chain, such as-(CH₂)₄(L-4), -(CH₂)₆- (L-6), and -CH₂CH(OH)CH₂H(L-3), etc., and were characterized in terms of the magnetic measurements and cyclic voltammetry. The complexes, Fe₂(L-3′0(NO₃)₅ showed subnormal magnetic moments, 4.10 BM at 299 K and 2.22 BM at 87 K, respectively, suggesting the presence of an alkoxo-bridge structure. This complex showed much higher catalytic activity for the O₂ oxidation of N, N, N′,N′-tetramethyl-1-1,4-diaminobenzene than those of the relevant mononuclear complexes and other binuclear complexes studied here which have no alkoxo-bridge. The complex reacts with catechol and hydrogen peroxide to form 1:1 adducts.     

Facile and greener hydrothermal honey-based synthesis of Fe3O 4/Au core/shell nanoparticles for drug delivery applications

In the present research, we report a greener, faster, and low-cost synthesis of gold-coated iron oxide nanoparticles (Fe₃O₄/Au-NPs) by different ratios (1:1, 2:1, and 3:1 molar ratio) of iron oxide and gold with natural honey (0.5% w/v) under hydrothermal conditions for 20 minutes. Honey was used as the reducing and stabilizing agent, respectively. The nanoparticles were characterized by X-ray diffraction (XRD), UV-visible spectroscopy, field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDXS), transmission electron microscopy (TEM), selected area electron diffraction (SAED), vibrating sample magnetometer (VSM), and fourier transformed infrared spectroscopy (FT-IR). The XRD analysis indicated the presence of Fe₃O₄/Au-NPs, while the TEM images showed the formation of Fe₃O₄/Au-NPs with diameter range between 3.49 nm and 4.11 nm. The VSM study demonstrated that the magnetic properties were decreased in the Fe₃O₄/Au-NPs compared with the Fe₃O₄-NPs. The cytotoxicity threshold of Fe₃O₄/Au-NPs in the WEHI164 cells was determined by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. It was demonstrated no significant toxicity in higher concentration up to 140.0 ppm which can become the main candidates for biological and biomedical applications, such as drug delivery.     

Comparative Study of Antibiofilm Activity of Copper Oxide and Iron Oxide Nanoparticles Against Multidrug Resistant Biofilm Forming Uropathogens

The effectiveness of the metal oxide nanoparticles viz. CuO and Fe₂O₃ as antibacterial agents against multidrug resistant biofilm forming bacteria was evaluated. CuO nanoparticles were also experimented for antibiofilm and time kill assay. The CuO displayed maximum antibacterial activity with zone of inhibition of (22 ± 1) mm against methicillin resistant Staphylococcus aureus (MRSA) followed by Escherichia coli (18 ± 1) mm. The Fe₂O₃ showed the zone of inhibition against MRSA of (14 ± 1) mm followed by E. coli (12 ± 1) mm. CuO proved to be more toxic than Fe₂O₃ nanoparticles showing significantly high antibacterial activity and found to possess dose dependent antibiofilm properties.     

The lactate-dependent enhancement of hydroxyl radical generation by the Fenton reaction

The effect of lactic acid (lactate) on Fenton based hydroxyl radical (^·OH) production was studied by spin trapping, ESR, and fluorescence methods using DMPO and coumarin-3-carboxylic acid (3-CCA) as the ^·OH traps respectively. The ^·OH adduct formation was inhibited by lactate up to 0.4mM (lactate/iron stoichiometry = 2) in both experiments, but markedly enhanced with increasing concentrations of lactate above this critical concentration. When the H₂O₂ dependence was examined, the DMPO-OH signal was increased linearly with H₂O₂ concentration up to 1 mM and then saturated in the absence of lactate. In the presence of lactate, however, the DMPO-OH signal was increased further with higher H₂O₂ concentration than 1 mM, and the saturation level was also increased dependent on lactate concentration. Spectroscopic studies revealed that lactate forms a stable colored complex with Fe³⁺ at lactate/Fe³⁺ stoichiometry of 2, and the complex formation was strictly related to the DMPO-OH formation. The complex formation did not promote the H₂O₂ mediated Fe³⁺ reduction. When the Fe³⁺-lactate (1:2) complex was reacted with H₂O₂, the initial rate of hydroxylated 3-CCA formation was linearly increased with H₂O₂ concentrations. All the data obtained in the present experiments suggested that the Fe³⁺-lactate (1:2) complex formed in the Fenton reaction system reacts directly with H₂O₂ to produce additional ^·OH in the Fenton reaction by other mechanisms than lactate or lactate/Fe³⁺ mediated promotion of Fe³⁺/Fe²⁺ redox cycling.     

Numbers of iron‐oxidizing bacteria and oxidation potential of sulfur and iron components in coal refuse amended with limestone and sewage sludge

Counts of acidophilic iron‐oxidizing bacteria, ratios of S₂O₃=—S/SO₄=—S and Fe⁺³/Fe⁺², and S₂O₃=—S oxidation potentials were examined over a two‐year period in coal refuse (acid gob) treated with limestone and/or sewage sludge. A non‐amended treatment was used as a control.

No significant difference in population counts of acidophilic iron‐oxidizing bacteria were observed between treatments in either year of the study. S₂O₃=—S/SO₄=—S and Fe⁺³/Fe⁺² ratios indicated active sulfur and iron oxidation suggesting that limestone and/or sewage sludge may be ineffective in suppressing pyrite oxidation. Under optimal conditions, S₂O₃=—S oxidation potentials (in vitro) showed a logarithmic increase in SO₄=—S formation for all four treatments over time. The final pH of the treatments following twenty days of perfusion ranged from 3.06 to 3.59.     

Syntheses, structures and magnetic properties of tetra- and heptanuclear iron(III) clusters incorporating phosphonate ligands

Two iron(III) complexes, [Fe₄OCl(O₂CMe)₃(O₃PC₆H₉)₃(py)₅] (1) and [Fe₇O₂(O₂CPh)₉(O₃PC₆H₉)₄(py)₆] (2), have been prepared through solution reactions of [Fe₃O(O₂CR)₆(H₂O)₃]Cl (R = Me, Ph) with cyclohexenephosphonic acid. Both compounds contain triangular oxo-centered [Fe₃(μ₃-O)]⁷⁺ units. In complex 1, the fourth iron atom is capped on this triangular unit through O-P-O bridges, forming a tetranuclear cluster with a tetrahedral arrangement of iron atoms. In complex 2, two equivalent [Fe₃(μ₃-O)]⁷⁺ units are connected by the fourth iron atom through four phosphonate ligands, forming a heptanuclear cluster. Variable temperature susceptibility measurements were performed for 1 and 2. Both exhibit dominant antiferromagnetic interactions between the Fe(III) centers.     

Effects of aluminum,iron, oxygen and nitrate additions on phosphorus release from the sediment of a Danish softwater lake

The effects of oxygen, aluminum, iron and nitrate additions on phosphate release from the sediment were evaluated in the softwater Lake Vedsted, Denmark, by a 34-day experiment with undisturbed sediment cores. Six treatments were applied: (1) Control - O₂ (0–20% saturation), (2) O₂ (100% saturation) (3) Al³⁺ – O₂, (4) Fe³⁺ + O₂, (5) Fe³⁺ – O₂, and (6) NO₃ ^– – O₂. Al₂(SO₄)₃*18 H₂O and FeCl₃*4H₂O were added in amounts that theoretically should immobilize the exchangeable P-pool in the top 5 cm of the sediment, while sodium nitrate concentrations were increased to 5 mg N l^–1. The four treatments with metals or NO₃ ^– reduced the P efflux from the sediment significantly as compared to the suboxic control treatment. Mean accumulated P-release rates for suboxic treatments with Al³⁺, Fe³⁺, and NO₃ ^– were: –0.27 mmol m^–2 (st. dev = 0.02 mmol m^–2, N = 5), 0.58 mmol m^–2 (st. dev = 0.30 mmol m^–2, N = 5) and 1.40 mmol m^–2 (st. dev = 0.14 mmol m^–2, N = 5), respectively. The oxic treatment with Fe³⁺ had a P efflux of 0.36 mmol m^–2 (st. dev = 0.08 mmol m^–2, N = 5). The two highest P-release rates were observed in the control treatment and the treatment with O₂ (14.50 mmol m^–2 (st. dev = 3.90 mmol m^–2, N = 5) and 2.31 mmol m^–2 (st. dev = 0.80 mmol m^–2, N = 5), respectively). In order to identify changes in the P and Fe binding sites in the sediment as caused by the treatments, a sequential P extraction procedure was applied on the sediment before and after the efflux experiment. Addition of O₂, Fe³⁺ and NO₃ ^– to the sediment increased the amounts of oxidized Fe³⁺ and P_BD. Al³⁺ addition resulted in a lower fraction of P_BD but a correspondingly higher fraction of Al-bound P. Addition of Al³⁺ decreased the Fe-efflux from the suboxic sediment as well as the amount of oxidized Fe³⁺ in the sediment. This questions the use of Al compounds that contain sulfate because of the possible formation of FeS, which will restrict upward migration of Fe²⁺ and the formation of new Fe-oxides in the surface sediment. Instead, we suggest the use of AlCl₃ for lake restoration purposes.     

Study of the magnetic properties of the mixed oxide Fe2O3-Fe2(MoO4)3 in the temperature range 2-300 K with different compositions

Powdered Fe₂O₃-Fe₂(MoO₄)₃ with different amounts of iron and molybdate precursors was prepared by a solvothermal route, followed by a supercritical drying and oxidation at 500 °C. The possibility to arrange Fe or Mo precursors in excess into a methanol solution makes one accessible to the preparation of iron(III) molybdate samples with different composition. The structural parameters and relationship between different phases in the composition are obtained from Rietveld profile refinement. Our intention was to modify the magnetic properties of Fe₂(MoO₄)₃ by adding the crystalline phase of Fe₂O₃, which carries a Fe-O magnetic component. A possible contribution to the magnetization and the magnetic susceptibility by this magnetic component is analyzed in the temperature range 2-300 K. The observed higher magnetic susceptibilities are compared to those reported.     

纳米铁氧化物对Pelotomaculum schinkii培养系丙酸厌氧降解产甲烷的影响

微生物能利用导电材料进行电子传递,提高种间电子传递效率。铁基纳米导电物质可以加速土壤及厌氧消化系统中微生物间的种间电子传递,促进有机废弃物的产甲烷过程。前期获得了厌氧丙酸富集培养系,互营丙酸氧化菌（Pelotomaculum schinkii）在培养系中占优势,本研究考察了10~4 000 mg/L 纳米铁氧化物对丙酸降解产甲烷过程的作用及微生物的影响。结果表明,低浓度的铁基纳米材料对丙酸降解有一定的促进作用,而高浓度会抑制产甲烷：10~1 000 mg/L纳米Fe₃O₄对产甲烷无明显影响,1 500~4 000 mg/L最大产甲烷速率抑制了26%~80%,延滞期增加了174%~222%;10~200 mg/L纳米Fe₂O₃使最大产甲烷速率提高了21%~29%,1 500~4 000 mg/L最大产甲烷速率抑制了48%~58%,延滞期增加了29%~85%。微生物群落解析结果表明,与对照相比,10~1 000 mg/L纳米Fe₂O₃使P. schinkii相对丰度略有增加,而4 000 mg/L纳米₃O₄/Fe₂O₃使P. schinkii的相对丰度下降了70.7%和55.9%,说明高浓度纳米铁氧化物会抑制P. schinkii的活性,导致丙酸降解及产甲烷速率降低。     

Synthesis of an iron(II)-braced proline-II tripod protein

Summary This paper describes the engineering of braced tripod proteins for use as molecular frameworks. Specifically, a 30-residue tripod-shaped protein with three proline-II helical legs braced by an iron(II)tris(bipyridine) complex was modularly designed, chemically synthesized, and biophysically characterized. Three copies of a 10-residue leg peptide were covalently linked through sulfide bonds to an N-terminal apex (1,3,5-tris(methylene)benzene) and by amide bonds to the brace (Fe^II (Mbc)₃: Mbc is 4′-methyl-2,2′-bipyridine-4-carbonyl). The leg peptide (H-Cys-Pro₅-Pra(Mbc)-Pro₃-NH₂: Pra iscis-4-amino-l-proline) was assembled by the solid-phase method using Boc-Pra(Mbc)-OH, which was synthesized in 75% overall yield by coupling Mbc-OH to the 4-amino group of Boc-Pra-OCH₃ and saponifying the methyl ester group. The iron(II)-braced tripod was assembled by S-alkylation of three copies of the leg peptide with 1,3,5-tris(bromomethyl)benzene followed by ligation of Fe²⁺ to the resulting unbraced tripod. The CD spectrum of the iron(II)-braced tripod showed a positive MLCT band at 570 nm and a negative π-π^* band at 312 nm, so its Fe^II(Mbc)₃ brace was predominantly in the Δ configuration. In a mostly acetonitrile solution at 25°C, the leg peptide and the unbraced tripod isomerized from the proline-II helical form into the proline-I helical form but the iron(II)-braced tripod remained in the proline-II helical form.     

Effects of various iron supply on oxidative stress development and ferritin formation in the common ice plants

Mesembryanthemum crystallinum L. plants were grown from seeds in perlite. At the age of 4 weeks (juvenile plants) or 6 weeks (adult plants), they were transferred on nutrient media with different Fe³⁺ content brought in as Fe₂(SO₄)₃—EDTA complex (pH 6.0): control, iron deficit, and iron “excess”. Adult plants grown in media differing in iron content were subjected to salinity (300 mM NaCl) during the last 8 days of growth. Biochemical analyses were performed after plant fixation in liquid nitrogen; simultaneously, the samples for electron microscopy were taken. Different content of available Fe³⁺ in medium, especially under salinity conditions, changed sharply the content of chlorophyll and proline, the rate of lipid peroxidation, the level of H₂O₂, the activities of antioxidant enzymes in the leaves and roots, the number and sizes of plastoglobules, and ferritin formation in plastids. Joint action of salinity and iron deficit enhanced oxidative stress development, whereas iron excess hampered oxidative reaction development, reduced the rate of lipid peroxidation, and increased the chlorophyll content. At iron excess, plastoglobule lysis in plastids did not occur, their number and sizes increased, and ferritin deposits appeared, whereas the latter were absent at iron deficit.     

Interactions of free copper (II) ions alone or in complex with iron (III) ions with erythrocytes of marine fish Dicentrarchus labrax

As a consequence of human activity, various toxicants - especially metal ions - enter aquatic ecosystems and many fish are exposed to considerable levels. As the free ion and in some complexes, there is no doubt that copper promotes damage to cellular molecules and structures through radical formation. Therefore, we have investigated the influence of copper uptake by the red blood of the sea bass (Dicentrarchus labrax), and its oxidative action and effects on cells in the presence of complexed and uncomplexed Fe³⁺ ions.Erythrocytes were exposed to various concentrations of CuSO₄, Fe(NO₃)₃, and K₃Fe(CN)₆ for up to 5 h, and the effects of copper ions alone and in the combination with iron determined. The results show that inside the cells cupric ion interacts with hemoglobin, causing methemoglobin formation by direct electron transfer from heme Fe²⁺ to Cu²⁺. Potassium ferricyanide as a source of complexed iron decreases Met-Hb formation induced by copper ions unlike Fe(NO₃)₃. We also found that incubation of fish erythrocytes with copper increased hemolysis of cells. But complexed and uncomplexed iron protected the effect of copper. CuSO₄ increased the level of lipid peroxidation and a protective effect on complexed iron was observed. Incubation of erythrocytes with copper ions resulted in the loss of a considerable part of thiol content at 10 and 20 μM. This effect was decreased by potassium ferricyanide and Fe(NO₃)₃ only after 1 and 3 h of incubation. The level of nuclear DNA damage assayed by comet assay showed that 20 μM CuSO₄ as well as 20 μM Fe(NO₃)₃ and 10 mM K₃Fe(CN)₆ induce single- and double-strand breaks. The lower changes were observed after the exposure of cells to K₃Fe(CN)₆. The data suggest that complexed iron can act protectively against copper ions in contrast to Fe(NO₃)₃.     

The function of chitosan/agarose biopolymer on Fe2O3 nanoparticles and evaluation of their effects on MCF-7 breast cancer cell line and expression of BCL2 and BAX genes

In recent decades, magnetic nanoparticles modified with biocompatible polymers have been recognized as a suitable tool for treating breast cancer. The aim of this research was to evaluate the function of chitosan/agarose-functionalized Fe₂O₃ nanoparticles on the MCF-7 breast cancer cell line and the expression of BCL2 and BAX genes. Free Fe₂O₃ nanoparticles were prepared by hydrothermal method. FTIR, XRD, SEM, DLS, VSM, and zeta potential analyses determined the size and morphological characteristics of the synthesized nanoparticles. The effect of Fe₂O₃ free nanoparticles and formulated Fe₂O₃ nanoparticles on induction of apoptosis was studied by double-dye Annexin V-FITC and PI. Also, the gene expression results using the PCR method displayed that Fe₂O₃ formulated nanoparticles induced BAX apoptosis by increasing the anti-apoptotic gene expression and decreasing the expression of pro-apoptotic gene BCL2, so the cell progresses to planned cell death. In addition, the results showed that the BAX/BCL2 ratio decreased significantly after treatment of MCF-7 cells with free Fe₂O₃ nanoparticles, and the BAX/BCL2 ratio for Fe₂O₃ formulated nanoparticles increased significantly. Also, to evaluate cell migration, the scratch test was performed, which showed a decrease in motility of MCF-7 cancer cells treated with Fe₂O₃ nanoparticles formulated with chitosan/agarose at concentrations of 10, 50, 100, and 200 μg/ml.     

Synthesis, characterization, X-ray molecular structure and catalase-like activity of a non-heme iron complex: Dichloro[N-propanoate-N,N-bis-(2-pyridylmethyl)amine]iron(III)

In this work we present the synthesis and characterization of the complex dichloro[N-propanoate-N,N-bis-(2-pyridylmethyl)amine]iron(III) [Fe^III(PBMPA)Cl₂]. The ligand LiPBMPA was synthesized through the Michael reaction of BMPA with methylacrylate, followed by alkaline hydrolysis. The complex [Fe^III(PBMPA)Cl₂] has been synthesized by the reaction of the ligand with FeCl₃ · H₂O and was mainly characterized by cyclic voltammetry, conductivimetry, and electronic, infrared and Mössbauer spectroscopies, and by X-ray structural analysis, which showed an iron center coordinated by one carboxylate oxygen in a monodentate way, one tertiary amine, two pyridine groups and two chloride ions. It has been proposed that in water the chloride ligands are shifted by the solvent molecules and the species [Fe^III(PBMPA)(H₂O)₂]Cl₂ is predominant. The catalase-like activity of the complex was tested in water, and it proved to be active in the hydrogen peroxide dismutation. Kinetics studies were conducted following the initial rates method. The reaction is first order in relation to both the complex and the hydrogen peroxide. Based on the presence of a lag phase that depends on the initial complex concentration, we propose that the active species that shows in situ catalase-like activity, is a binuclear complex.     

Penicillin V production by Penicillium chrysogenum in the presence of Fe3+ and in low-iron culture medium

Late-exponential-phasePenicillium chrysogenum mycelia grown in a complex medium possessed an intracellular iron concentration of 650 μmol/L (2.2±0.6 μmol per g mycelial dry mass). This iron reserve was sufficient to ensure growth and antibiotic production after transferring mycelia into a defined low-iron minimal medium. Although the addition of Fe³⁺ to the Fe-limited cultures increased significantly the intracellular iron levels the surplus iron did not influence the production of penicillin V. Supplements of purified majorP. chrysogenum siderophores (coprogen and ferrichrome) into the fermentation media did not affect the β-lactam production and intracellular iron level. Neither 150 nor 300 μmol/L extracellular Fe³⁺ concentrations disturbed the glutathione metabolism of the fungus, and increased the oxidative stress caused by 700 mmol/L H₂O₂. Nevertheless, when iron was applied in the Fe^II oxidation state the oxidative cell injuries caused by the peroxide were significantly enhanced.     

γ-Fe2O3 nanoparticle in NaY-zeolite matrix: Preparation, characterization, and heterogeneous catalytic epoxidation of olefins

Nano-sized crystals of maghemite iron oxide (γ-Fe₂O₃) were synthesized onto the surface of NaY-zeolite crystals by immobilizing a polynuclear iron complex [Fe₄O₂(O₂CCH₃)₇(bpy)₂](ClO₄) (bpy = 2,2′-bipyridine) and subsequent calcination of the material in oxygen. Superparamagnetic γ-Fe₂O₃ particles with sizes ∼5 nm were formed on the surface of the zeolite matrix. The nano-composite, γ-Fe₂O₃@NaY has been subsequently subjected for thorough characterization with several spectroscopic techniques as well as magnetic and transmission electron microscopic measurements. This confirms the formation of maghemite nanoparticles on a NaY-zeolite surface. γ-Fe₂O₃@NaY shows a remarkable catalytic efficiency in epoxidation reactions with various olefins using tert-BuOOH as oxidant. Notably, styrene shows a remarkable high conversion (90%) as well as epoxide selectivity (95%) while trans-stilbene is completely converted to its oxide with tert-BuOOH over a γ-Fe₂O₃@NaY catalyst.     

Aryl fluorosulfate analogues as potent antimicrobial agents: SAR,cytotoxicity and docking studies

A series of aryl fluorosulfate analogues (1–37) were synthesized and tested for in vitro antibacterial and antifungal studies, and validated by docking studies. The compounds 9, 12, 14, 19, 25, 26, 35, 36 and 37 exhibited superior antibacterial potency against tested bacterial strains, while compounds 2, 4, 5, 15, 35, 36 and 37 were found to have better antifungal activity against tested fungal strains, compared to standard antibiotic gentamicin and ketoconazole respectively. Among all the synthesized 37 analogs, compounds 25, 26, 35, 36 and 37 displayed excellent anti-biofilm property against Staphylococcus aureus. The structure–activity relationship (SAR) revealed that the antimicrobial activity depends upon the presence of –OSO₂F group and slender effect of different substituent’s on the phenyl rings. The electron donating (OCH₃) groups in analogs increase the antibacterial activity, and interestingly the electron withdrawing (Cl, NO₂, F and Br) groups increase the antifungal activity (except compound 35, 36 and 37). The mechanism of potent compounds showed membrane damage on bacteria confirmed by SEM. Compounds 35, 36 and 37 exhibited highest glide g-scores in molecular docking studies and validated the biocidal property.     

Transport of Intranasally Instilled Fine Fe2O3 Particles into the Brain: Micro-distribution, Chemical States, and Histopathological Observation

It has been demonstrated that inhaled fine (d < 2.5 μm) and ultrafine (d < 100 nm) particles produce more severe toxicity than coarse particles. Some recent data support the concept that the central nervous system (CNS) may be a target for the inhaled fine particulates. This work describes initial observation of the transport of intranasally instilled fine ferric oxide (Fe₂O₃) particles in animal brain. The iron micro-distribution and chemical state in the mice olfactory bulb and brain stem on day 14 after intranasal instillation of fine Fe₂O₃ particle (280 ± 80 nm) suspension at a single dose of 40 mg/kg body weight were analyzed by synchrotron radiation x-ray fluorescence and x-ray absorption near-edge structure (XANES). The micro-distribution map of iron in the olfactory bulb and brain stem shows an obvious increase of Fe contents in the olfactory nerve and the trigeminus of brain stem, suggesting that Fe₂O₃ particles were possibly transported via uptake by sensory nerve endings of the olfactory nerve and trigeminus. The XANES results indicate that the ratios of Fe (III)/Fe (II) were increased in the olfactory bulb and brain stem. The further histopathological observation showed that the neuron fatty degeneration occurred in the CA3 area of hippocampus. Such results imply an adverse impact of inhalation of fine Fe₂O₃ particles on CNS.