Plasmid pBR322 Research Articles

The Phytochemical constituents and biological activities of sungkai (Peronema canescens Jack) leaves hydroethanolic extracts

Peronema canescens, Jack commonly known as "sungkai," has been traditionally used as a herbal medicine for various health conditions. This study aimed to explore the bioactive compound of the P. canescens leaves hydroethanolic extract, along with assessing its antioxidant and antimutagenic properties. Liquid chromatography-mass spectrometry (LC-MS) was utilized for phytochemical analysis of the hydroethanolic extracts, while antioxidant activity was evaluated through the DPPH radical scavenging method. Quantification of total phenolic and flavonoid content was achieved via colorimetric analysis. Furthermore, the DNA protection activity was assessed using plasmid pBR322 subjected to free radical treatment. The primary bioactive compounds identified in the P. canescens hydroethanolic extracts belonged to the alkaloid and flavonoid groups. The antioxidant activity of P.canescens leaves hydroethanolic extracts showed an IC50 value of 0.02±0.00 µg/mL. Additionally, the total flavonoid and phenolic content were measured at 33,769±3,626 µg QE/mL and 638,924±6,683 µg GAE/mL, respectively. Notably, P.canescens exhibited significant potential in mitigating DNA damage. In conclusion, the P. canescens leaves hydroethanolic extracts demonstrate promising attributes as a herbal medicine, highlighting notable antioxidant and antimutagenic effects.

The Effect of Torbangun (Coleus amboinicus Lour) Leaf Extract on Antibiotic Resistant Bacteria Escherichia coli pBR322 and Toxicity Tests on Artemia salina Leach

Inappropriate antibiotic use can lead to antibiotic resistance, causing many problems in the treatment of Escherichia coli infection. One way to avoid resistance is to use the traditional medicine Coleus amboinicus Lour, also known as Torbangun in Indonesia. The purpose of this study was to determine the inhibitory ability of 70% ethanol extract of Torbngun leaf against Escherichia coli pBR322 has plasmid pBR322, which is resistant to antibiotics Ampicillin and Tetracycline based on activity and minimum inhibitory concentration. Extraction was carried out using the maceration method. The presence of inhibition zones indicated antibacterial activity. The appearance of the inhibition zone at the minimum concentration indicated the minimum inhibitory concentration. Following this, the cytotoxic activity was evaluated using the brine shrimp lethality test. Data analysis was performed using an unpaired t-test using GraphPad Prism® software. Antibacterial activity tests showed that a 15% torbangun leaf extract concentration had inhibitory power against Escherichia coli pBR322. The toxicity test of torbangun leaf extract against Artemia salina Leach shrimp larvae showed LD50 results at a concentration of 150 ppm.

DNA Hyperstructure.

This study presents a new procedure to condense DNA molecules and precipitate them onto a glass slide. The resulting DNA molecules undergo autonomous self-assembly, creating closed superstructures on the micrometer scale, which are called DNA hyperstructures. These structures can be observed using low-magnification (4×) light microscopy. Precisely controlling the alcohol/glacial acetic acid ratio and DNA concentration during precipitation enabled the regulation of structure compaction on the slide. The alcohol/glacial acetic acid ratio is inversely proportional to the DNA concentration to achieve optimal compaction on the slide. Confocal microscopy fluorescence analysis of DNA extracts stained with DAPI shows that nucleic acids self-assemble to form structures during precipitation on the slide. This methodology is relevant since it facilitates the precipitation and visualization of DNA, regardless of its origin or molecular weight. To confirm its versatility, results with DNA extracted from human peripheral blood, the Lambda virus, and plasmid pBR322 are presented. The study examined the morphological features of DNA hyperstructures in both healthy individuals and those diagnosed with different medical conditions or illnesses, revealing distinct patterns specific to each case. This innovative technology has potential for disease detection in peripheral blood samples, ranging from cancer and Alzheimer's disease to determining the gender of the gestational product at an early stage.

Crystal structure of a phenoxyl radical complex relevant to the metal site of the galactose oxidase enzyme: A facile one-pot synthesis, evidence for hydrogen atom transfer and DNA cleavage via self-activation.

Copper complexes [Cu(L1H)ClO4] (1) and [Cu(L2)NO3] (2), which are relevant to the metal site of the galactose oxidase enzyme, were synthesized and characterized by different spectroscopic methods. L1H2 and L2H2 [where L1H2 stands for 2,2'-((1E,1'E)(2,2'-(pyridine-2,6-diyl)bis(2-phenylhydrazin-2-yl-1-ylidene))bis(methanylylidene))diphenol and L2H2 stands for 6,6'-((1E,1'E)-(2,2'-(pyridine-2,6-diyl)bis(2-phenylhydrazin-2-yl-1-ylidene))bis(methanylylidene))bis(2,4-di-tert-butylphenol), H stands for dissociable proton] are pentadentate ligands. These ligands provide pyridyl N, two imine N, and two non-innocent phenoxyl and phenolato O donors, forming complex 1 as a non-radical complex, while complex 2 is a phenoxyl radical complex. The molecular structures of complexes 1 and 2 were authenticated by X-ray crystallography. Benzyl alcohol oxidation was investigated, and the conversion of 9,10-dihydroanthracene to anthracene was examined to scrutinize the H-atom abstraction reaction. Nuclease activity with complexes 1 and 2 was investigated by self-activated plasmid DNA (pBR322) cleavage. Non-innocent properties of the ligand-containing phenolato function were investigated by DFT calculations.

Coordination compounds of cobalt(II) with carboxylate non-steroidal anti-inflammatory drugs: structure and biological profile.

Fourteen cobalt(II) complexes with the non-steroidal anti-inflammatory drugs sodium meclofenamate, tolfenamic acid, mefenamic acid, naproxen, sodium diclofenac, and diflunisal were prepared in the presence or absence of a series of nitrogen-donors (namely imidazole, pyridine, 3-aminopyridine, neocuproine, 2,2'-bipyridine, 1,10-phenanthroline and 2,2'-bipyridylamine) as co-ligands and were characterised by spectroscopic and physicochemical techniques. Single-crystal X-ray crystallography was employed to determine the crystal structure of eight complexes. The biological profile of the complexes was investigated regarding their interaction with serum albumins and DNA, and their antioxidant potency. The interaction of the compounds with calf-thymus DNA takes place via intercalation. The ability of the complexes to cleave pBR322 plasmid DNA at the concentration of 500 μM is rather low. The complexes demonstrated tight and reversible binding to human and bovine serum albumins and the binding site of bovine serum albumin was also examined. In order to assess the antioxidant activity of the compounds, the in vitro scavenging activity towards free radicals, namely 1,1-diphenyl-picrylhydrazyl and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid), and their ability to reduce H2O2 were studied.

Synthesis, structural characterization, and DNA binding/cleavage studies of diorganotin(IV) carboxylates and their complexes with 1,10-phenanthroline: X-ray structures of [Me8Sn4(p-FC6H4CO2)4O2], [Bu2Sn(p-NO2C6H4CO2)2.phen], and DFT studies

The present study is focused on the mode of DNA-interactions with diorganotin(IV) carboxylates and their 1,10-phenanthroline (phen) complexes, and revealed that the planarity and extended π system of phen may increase the probability of DNA intercalation. Diorganotin(IV) derivatives of p-fluoro-/p-hydroxy-/p-nitro benzoic acid, viz. Bu2Sn(p-XC6H4CO2)2: X = F (1), OH (2), NO2 (3), Oct2Sn(p-NO2C6H4CO2)2 (4), and Me8Sn4(p-FC6H4CO2)4O2 (5), and their complexes with phen viz. Bu2Sn(p-XC6H4CO2)2.phen: X = F (6), OH (7), NO2 (8), Oct2Sn(p-NO2C6H4CO2)2.phen (9), and Me2Sn(p-FC6H4CO2)2.phen (10) have been synthesized and characterized by using various techniques including single crystal X-ray diffraction studies, nuclear magnetic resonance (1H, 13C, and 119Sn NMR), electrospray ionization mass spectrometry (ESI-MS), infrared (FT-IR), and elemental analysis. Based on crystal data, complexes (5) and (8) have a P-1 space group with a triclinic crystal system. In the octahedral geometry of complex (5), Sn atom has a tetranuclear Sn4O2 core, whereas complex (8) has a pentagonal bipyramidal geometry around Sn atom. The LanL2Z basis set has been employed for optimized gas-phase geometries, and the calculated ∠C-Sn-C bond angles agree with those obtained from NMR/X-ray studies. UV-visible, fluorescence and circular dichroism (CD) titrations showed interaction with Calf Thymus DNA (CT-DNA), and Kb and KSV values in the order of 103–105 M−1 indicate intercalation within the base pairs or in minor groove. Further, gel electrophoreses studies indicate that all of the complexes have efficiently cleaved plasmid pBR322 DNA into three bands; supercoiled, nicked/circular along with linear structure. The intriguing biophysical results suggest that these complexes may have anticancer potential.

Assessing phytotoxicity and cyto-genotoxicity of two insecticides using a battery of in-vitro biological assays.

Intensive use of chemical pesticides in agriculture poses environmental risks and may have negative impacts on agricultural productivity. The potential phytotoxicity of two chemical pesticides, chlorpyrifos (CPS) and fensulfothion (FSN), were evaluated using Cicer arietinum and Allium cepa as model crops. Different concentrations (0-100 μgmL-1) of both CPS and FSN decreased germination and biological attributes of C. arietinum. High pesticide doses significantly (p≤0.05) caused membrane damage by producing thiobarbituric acid reactive substances (TBARS) and increasing proline (Pro) content. Pesticides elevated ROS levels and substantially increased the superoxide anions and H2O2 concentrations, thus aggravating cell injury. Plants exposed to high pesticide dosages displayed significantly higher antioxidant levels to combat pesticide-induced oxidative stress. Ascorbate peroxidase (APX), guaiacol peroxidase (GPX), catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) increased by 48%, 93%, 71%, 52% and 94%, respectively, in C. arietinum roots exposed to 100 µgFSNmL-1. Under CLSM, pesticide-exposed C. arietinum and 2',7'-dichlorodihydrofluorescein diacetate (2'7'-DCF) and 3,3'-diaminobenzidine stained roots exhibited increased ROS production in a concentration-dependent manner. Additionally, enhanced Rhodamine 123 (Rhd 123) and Evan's blue fluorescence in roots, as well as changes in mitochondrial membrane potential (ΔΨm) and cellular apoptosis, were both associated with high pesticide dose. Allium cepa chromosomal aberration (CAs) assay showed a clear reduction in mitotic index (MI) and numerous chromosomal anomalies in root meristematic cells. Additionally, a-dose-dependent increase in DNA damage in root meristematic cells of A. cepa and conversion of the super-coiled form of DNA to open circular in pBR322 plasmid revealed the genotoxic potential of pesticides. The application of CPS and FSN suggests phytotoxic and cyto-genotoxic effects that emphasize the importance of careful monitoring of current pesticide level in soil before application and addition at optimal levels to soil-plant system. It is appropriate to prepare both target-specific and slow-release agrochemical formulations for crop protection with concurrent safeguarding of agroecosystems.

Platinum(IV)-Gold(I) Agents with Promising Anticancer Activity: Selected Studies in 2D and 3D Triple-Negative Breast Cancer Models.

New heterometallic binuclear and trinuclear platinum(IV)-gold(I) compounds of the type [Pt(L)n Cl2 (OH){(OOC-4-C6 H4 -PPh2 )AuCl}x ] (L=NH3 , n=2; x=1, 2; L=diaminocyclohexane, DACH, n=1; x=2) are described. These compounds are cytotoxic and selective against a small panel of renal, bladder, ovarian, and breast cancer cell lines. We selected a trinuclear PtAu2 compound containing the PtIV core based on oxaliplatin, to further investigate its cell-death pathway, cell and organelle uptake and anticancer effects against the triple-negative breast cancer (TNBC) MDA-MB-231 cell line. This compound induces apoptosis and accumulates mainly in the nucleus and mitochondria. It also exerts remarkable antimigratory and antiangiogenic properties, and has a potent cytotoxic effect against TNBC 3D spheroids. Trinuclear compounds do not seem to display relevant interactions with calf thymus (CT) DNA and plasmid (pBR322) even in the presence of reducing agents, but inhibit pro-angiogenic enzyme thioredoxin reductase (TrxR) in TNBC cells.

Piperazin incorporated Schiff Base derivatives: Assessment of in vitro biological activities, metabolic enzyme inhibition properties, and molecular docking calculations.

The cytotoxic activities of the compounds were determined by the 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) method in human breast cancer (MCF-7), human cervical cancer (HeLa), and mouse fibroblast (L929) cell lines. The compounds MAAS-5 and four modified the supercoiled tertiary structure of pBR322 plasmid DNA. MAAS-5 showed the highest cytotoxic activity in HeLa, MCF-7, and L929 cells with IC50 values of 16.76 ± 3.22, 28.83 ± 5.61, and 2.18 ± 1.22 µM, respectively. MAAS-3 was found to have almost the lowest cytotoxic activities with the IC50 values of 93.17 ± 9.28, 181.07 ± 11.54, and 16.86 ± 6.42 µM in HeLa, MCF-7, and L929 cells respectively at 24 h. Moreover, the antiepileptic potentials of these compounds were investigated in this study. To this end, the effect of newly synthesized Schiff base derivatives on the enzyme activities of carbonic anhydrase I and II isozymes (human carbonic anhydrase [hCA] I and hCA II) was evaluated spectrophotometrically. The target compounds demonstrated high inhibitory activities compared with standard inhibitors with Ki values in the range of 4.54 ± 0.86-15.46 ± 8.65 nM for hCA I (Ki value for standard inhibitor = 12.08 ± 2.00 nM), 1.09 ± 0.32-29.94 ± 0.82 nM for hCA II (Ki value for standard inhibitor = 18.22 ± 4.90 nM). Finally, the activities of the compounds were compared with the Gaussian programme in the B3lyp, HF, M062X base sets with 6-31++G (d,p) levels. In addition, the activities of five compounds against various breast cancer proteins and hCA I and II were compared with molecular docking calculations. Also, absorption, distribution, metabolism, excretion, and toxicity analysis was performed to investigate the possibility of using five compounds as drug candidates.

Synthesis of novel Cu(II) complexes with N2O2 ligands: Characterization, theoretical calculations, antimicrobial, antioxidant, DNA binding, and in vitro anticancer activity studies

The aim was to investigate the in vitro antimicrobial, antioxidant, cytotoxic activities and pBR322 Plasmid DNA interaction potentials of newly synthesized Schiff bases and their copper complexes. Cytotoxic activities of these compounds were determined by MTT methods in human breast cancer (MCF-7), human cervical cancer (HeLa) and mouse fibroblast (L929) cell lines. The determination of changes in oxidant and antioxidant load of the cell after application of these compounds were investigated with the aid of Rel Assay Diagnostics kits. It was found that the some of the compounds had moderate antimicrobial activity, and oxidative stress index. According to plasmid DNA interaction studies, synthesized complexes modified the tertiary structure of pBR322 plasmid DNA. The compound Bis-Napht showed the highest cytotoxic activity in HeLa, MCF-7 and L929 cells at an IC50 dose of 3 ± 1 µM, 5 ± 1 µM and 3 ± 1 µM respectively. Compound Bis-Sal was determined to have lower cytotoxic activity in L-929 cells at an IC50 dose of 106 ± 9 µM at 24 h compared to other compounds. Ligand compounds and their metal complexes were optimized on the B3LYP, HF, and M06-2x methods with the 6–31++g(d,p) basis set. Afterwards, their activities were compared against crystal structure of the BRCT repeat region from the breast cancer associated protein, (BRCA1) (PDB ID: 1JNX) and crystal Structure of CDK2 receptor of cervical cancer cell proteins (PDB ID: 4BGH). To examine the interactions occurring in more detail, Protein-Ligand Interaction Profiler analysis was performed and all chemical interactions that occurred were determined.

Exploring the Potential of Spirulina (Arthrospira platensis) Aqueous Extract in Preventing Glycation of Hemoglobin and pBR322 Plasmid

Background Spirulina ( Arthrospira platensis), a cyanobacterium, is being consumed worldwide owing to its high nutritional value and therapeutic potential. Objectives This study aims to determine the phytochemical content, antioxidant capacity, and antiglycation property of A. platensis PCC 7345 aqueous extract against glucose, fructose, and ribose-mediated glycation of hemoglobin. Materials and Methods The antioxidant property of the extract was determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and a nitric oxide scavenging assay. Protein glycation and its subsequent prevention were interpreted by observing a reduction in browning, fructosamine, glycated hemoglobin (HbA1c) level, protein carbonyl content, advanced glycation end products (AGEs) formation, and protein aggregation using spectrophotometry and spectrofluorometry. The prevention of strand nicking/breaks in the pBR322 plasmid was analyzed using electrophoresis, and the change in integrated density was calculated using ImageJ software. Results The extract showed very good antioxidant potential, which is evident and could be estimated from the inhibition concentration (IC50) values that were 45.97, 31.09, and 52.29 µg/mL in the DPPH, ABTS, and nitric oxide scavenging assays, respectively. A. platensis aqueous extract was found to be the most effective in preventing glucose-mediated glycation and protein aggregation, wherein 100 µg/mL of the extract could effectively cause ~50% inhibition in the formation of early and AGEs and prevented the formation of protein aggregates. The highest antiglycating potential of the extract was observed in glucose-mediated glycation, followed by fructose and ribose. The formation of four fluorescent AGEs, such as argpyrimidine, vesper lysine A, pentosidine, and crossline, was reduced. The extract could prevent 97% of DNA nicking in pBR322. Conclusion The aqueous extract of A. platensis has a potent ability to prevent glycation and its secondary complications.

In Vitro Modulation of Genotoxicity and Oxidative Stress by Polyphenol-Rich Fraction of Chinese Ladder Brake (Pteris vittata L.).

Pteris vittata L. is a terrestrial genus growing in moist, shady forests and on hillsides. The plant has considerable ethnomedicinal importance. Investigations have been carried out on chemical profiling and antioxidant compounds from some genera of pteridophytes but studies on the biological properties of P. vittata are lacking. Therefore, the present study investigates antioxidant, antigenotoxic, and antiproliferative potential of the aqueous fraction of P. vittata (PWE). A battery of assays were carried out to assess the antioxidant potential of the PWE. SOS chromotest and DNA nicking assay were used to evaluate the antigenotoxicity of the fraction. The cytotoxic effect of PWE was analyzed using MTT and Neutral Single Cell Gel Electrophoresis comet assay. EC50 of 90.188µg/ml, 80.13µg/ml, 142.836µg/ml, and 12.274µg/ml was obtained in DPPH, superoxide anion scavenging, reducing power and lipid peroxidation assays, respectively. PWE was potent in inhibiting Fenton's reagent-induced nicking of pBR322 plasmid. The fraction significantly inhibited hydrogen peroxide (H2O2) and 4-nitroquinoline-N-oxide (4NQO) induced mutagenicity and a reduction in induction factor was found with increased PWE concentration. GI50 of 147.16µg/ml was obtained in MTT assay in human MCF-7 breast cancer cell line. PWE induced apoptosis as confirmed from confocal microscopy studies. The protective effects can be attributed to the presence of the phytochemicals in PWE. These results will be helpful in the development of functional food characteristics, as well as unravel the benefits of pteridophytes as promoters of health.

Quantification of damage to plasmid DNA from 35MeV electrons, 228MeV protons and 300 kVp X-rays in varying hydroxyl radical scavenging environments.

The pBR322 plasmid DNA was irradiated with 35MeV electrons, 228MeV protons and 300 kVp X-rays to quantify DNA damage and make comparisons of DNA damage between radiation modalities. Plasmid was irradiated in a medium containing hydroxyl radical scavengers in varying concentrations. This altered the amount of indirect hydroxyl-mediated DNA damage, to create an environment that is more closely associated with a biological cell. We show that increasing hydroxyl scavenger concentration significantly reduced post-irradiation DNA damage to pBR322 plasmid DNA consistently and equally with three radiation modalities. At low scavenging capacities, irradiation with both 35MeV electrons and 228MeV protons resulted in increased DNA damage per dose compared with 300 kVp X-rays. We quantify both single-strand break (SSB) and double-strand break (DSB) induction between the modalities as a ratio of yields relative to X-rays, referred to as relative biological effectiveness (RBE). RBESSB values of 1.16 ± 0.15 and 1.18 ± 0.08 were calculated for protons and electrons, respectively, in a low hydroxyl scavenging environment containing 1mM Tris-HCl for SSB induction. In higher hydroxyl scavenging capacity environments (above 1.1 × 106s-1), no significant differences in DNA damage induction were found between radiation modalities when using SSB induction as a measure of RBE. Considering DSB induction, significant differences were only found between X-rays and 35MeV electrons, with an RBEDSB of 1.72 ± 0.91 for 35MeV electrons, indicating that electrons result in significantly more SSBs and DSBs per unit of dose than 300 kVp X-rays.

PH-Sensitive Gold Nanorods for Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) Delivery and DNA-Binding Studies.

A facile experimental protocol for the synthesis of poly(ethylene glycol)-modified (PEGylated) gold nanorods (AuNRs@PEG) is presented as well as an effective drug loading procedure using the non-steroidal anti-inflammatory drug (NSAID) naproxen (NAP). The interaction of AuNRs@PEG and drug-loaded AuNRs (AuNRs@PEG@NAP) with calf-thymus DNA was studied at a diverse temperature revealing different interaction modes; AuNRs@PEG may interact via groove-binding and AuNRs@PEG@NAP may intercalate to DNA-bases. The cleavage activity of the gold nanoparticles for supercoiled circular pBR322 plasmid DNA was studied by gel electrophoresis while their affinity for human and bovine serum albumins was also evaluated. Drug-release studies revealed a pH-sensitive behavior with a release up to a maximum of 24% and 33% NAP within the first 180 min at pH = 4.2 and 6.8, respectively. The cytotoxicity of AuNRs@PEG and AuNRs@PEG@NAP was evaluated against MCF-7 and MDA-MB-231 breast cancer cell lines. The development of AuNRs as an efficient non-steroidal anti-inflammatory drugs (NSAIDs) delivery system for chemotherapy is still in its infancy. The present work can shed light and inspire other research groups to work in this direction.

Structural insights into interactions of new polymeric (μ–oxo) bridged Cu(II) complexes of taurine with yeast tRNA by spectroscopic and computational approaches and its application towards chemoresistant cancer lines

RNA-targeted drugs are considered as safe treatment option for the cure of many chronic diseases preventing off-targeted delivery and acute toxic manifestations. FDA has approved many such RNA therapies in different phases of clinical trials, validating their use for the treatment of various chronic diseases. We report herein, new water-soluble (μ–oxo) bridged polymeric Cu(II) complexes of taurine (2–aminoethane sulfonic acid) complexes 1 and 2. The therapeutic potency of 1 and 2 was ascertained by studying biophysical interactions with tRNA/ct-DNA. The experimental results demonstrated that the complexes interacted avidly to nucleic acids through intercalation mode depicting a specific preference for tRNA in comparison to ct–DNA and, moreover 2 showed higher binding propensity than 1. The electrophoretic behaviour of the complexes with plasmid pBR322 DNA and tRNA were examined by gel mobility assay that revealed a concentration-dependent activity with complex 2 performing more efficient cleavage as compared to complex 1. Cytotoxicity results on cancer cell strains displayed higher cytotoxicity than complex 1 against treated cancer cells. The synthesized copper(II) taurine complexes have met the basic criteria of anticancer drug design as they are structurally well-characterized, exhibiting good solubility in water, lipophilic in nature with superior intercalating propensity towards tRNA and cytotoxic in nature.

Exploration of the DNA Photocleavage Activity of O-Halo-phenyl Carbamoyl Amidoximes: Studies of the UVA-Induced Effects on a Major Crop Pest, the Whitefly Bemisia tabaci

The DNA photocleavage effect of halogenated O-carbamoyl derivatives of 4-MeO-benzamidoxime under UVB and UVA irradiation was studied in order to identify the nature, position, and number of halogens on the carbamoyl moiety that ensure photoactivity. F, Cl, and Br-phenyl carbamate esters (PCME) exhibited activity with the p-Cl-phenyl derivative to show excellent photocleavage against pBR322 plasmid DNA. m-Cl-PCME has diminished activity, whereas the presence of two halogen atoms reduced DNA photocleavage. The substitution on the benzamidoxime scaffold was irrelevant to the activity. The mechanism of action indicated function in the absence of oxygen, probably via radicals derived from the N-O bond homolysis of the carbamates and in air via hydroxyl radicals and partially singlet oxygen. The UVA-vis area of absorption of the nitro-benzamidoxime p-Cl-PCMEs allowed for the investigation of their potential efficacy as photopesticides under UVA irradiation against the whitefly Bemisia tabaci, a major pest of numerous crops. The m-nitro derivative exhibited a moderate specificity against the adult population. Nymphs were not affected. The compound was inactive in the dark. This result may allow for the development of lead compounds for the control of agricultural insect pests that can cause significant economic damage in crop production.

Evaluation of Silybum marianum seed extract and vitamin B6 derivatives on methylglyoxal and sugar-induced oxidative DNA damage

AbstractReducing sugars are known to generate reactive oxygen species (ROS), mainly by means of the glycation reaction. The hydroxyl radical, a prominent entity of ROS, is known to alter cellular DNA and induces damage to DNA, and plays a role in diseases such as diabetes mellitus. In this study, the oxidative damage of DNA induced by the lysine/Fe3+/MG reaction was investigated. Silybum marianum seeds extract (SlyE), standard silymarin (Sly), and vitamin B6 derivatives, pyridoxal-5-phosphate (PLP), pyridoxamine (PM), and pyridoxine (P) in reversing glycation-induced damage in DNA were evaluated. In addition, different sugars and sugar phosphates were incubated with plasmid pBR 322 DNA to control and compare their harmful effects. Our results revealed that SlyE protected lysine/Fe3+/MG induced oxidative DNA damage more effectively than Sly. Vitamins, on the other hand, prevented this DNA damage in the order of PLP>P>PM. The DNA altering and damaging intensity of sugars and sugar phosphates tested increased considerably in the following order: Ribose-5-phosphate > fructose-6-phosphate > ribose > fructose > fructose-1,6 biphosphate > glucose-6 phosphate > glucose. The results show that the lysine/Fe3+/MG glycation reaction can cause oxidative damage of DNA through a mechanism involving hydroxyl radicals. It also provides evidence that ribose-5-phosphate and fructose and its phosphate metabolites can alter DNA more rapidly in vitro than glucose and its phosphate metabolites.

Adsorption of antibiotic, heavy metal and antibiotic plasmid by a wet-state silicon-rich biochar/ferrihydrite composite to inhibit antibiotic resistance gene proliferation/transformation

Decreasing bioaccessible antibiotics, heavy metals, and antibiotic resistance genes (ARGs) in soil by adsorption is an attractive, but unrealized, approach for ARG risk reduction. This approach has the potential to reduce the (co)selection pressure from antibiotics and heavy metals on bacteria and ARG horizontal gene transformation to pathogens. Here, a wet-state silicon-rich biochar/ferrihydrite composite (SiC–Fe(W)) synthesized by loading ferrihydrite onto rice straw-derived biochar was examined for i) adsorption of oxytetracycline and Cu2+ to reduce (co)selection pressure and ii) adsorption of extracellular antibiotic resistance plasmid pBR322 (containing tetA and blaTEM-1) to inhibit ARG transformation. SiC–Fe(W) gained the adsorption priority of biochar (for Cu2+) and wet-state ferrihydrite (for oxytetracycline and pBR322) and showed adsorptive enhancement (for Cu2+ and oxytetracycline) from a more wrinkled and exposed surface from biochar silica-dispersed ferrihydrite and a more negatively charged biochar, and the adsorption capacity for SiC–Fe(W) was 17–135 times that of soil. Correspondingly, 10 g/kg SiC–Fe(W) amendment increased the soil adsorption coefficient Kd by 31%–1417% and reduced the selection pressure from dissolved oxytetracycline, co-selection pressure from dissolved Cu2+, and transformation frequency of pBR322 (assessed with Escherichia coli). The development of Fe–O–Si bonds on silicon-rich biochar in alkaline enhanced ferrihydrite stability and adsorption capacity (for oxytetracycline), presenting a new potential strategy of biochar/ferrihydrite composite synthesis for adsorptive inhibition of ARG proliferation and transformation in ARG pollution control.

Crystal structure, fluorescence, magnetic properties and DNA interaction of four novel binuclear LnⅢ2 compounds with Schiff ligand

Four new Ln2 compounds, [Ln2(H2L−)2(acac)2(CH3O)2] (Ln = Sm(1), Tb(2), Ho(3) and Er(4), H3L = 2‑hydroxy-N’-[(1E)-(8-hydroxyquinolin-2-yl)methylidene]benzohydrazide), were synthesized by using a multidentate Schiff ligand and lanthanide β-diketone salts via solvent evaporation methods. The X-ray structural analysis reveal that the four Ln2 compounds are dinuclear compounds and each Ln(Ⅲ) ion is eight-coordinated. The two central Ln(Ⅲ) ions are bridged by two μ2O atoms from 8-hydroxyquinoline Schiff base ligands, leading to a parallelogram Ln2O2 core. The magnetism investigation shows that compound 2 display slow magnetic relaxation behavior under zero dc field (ΔE/kB = 19.77 K and τ0 = 1.35 × 10−6 s). Subsequent studies strongly suggested that the four Ln2 compounds binded to Calf thymus DNA (CT-DNA) through intercalative mode and have pBR322 plasmid DNA cleavage ability. This work will provide more insights for the design and investigation of lanthanide-based SMMs, and has certain reference value to study the interaction between compound and DNA.

Induction of DNA strand breaks and oxidative base damages in plasmid DNA by ultra-high dose rate proton irradiation

Purpose Radiation cancer therapy with ultra-high dose rate (UHDR) exposure, so-called FLASH radiotherapy, appears to reduce normal tissue damage without compromising tumor response to therapy. The aim of this study was to clarify whether a 59.5 MeV proton beam at an UHDR of 48.6 Gy/s could effectively reduce the DNA damage of pBR322 plasmid DNA in solution compared to the conventional dose rate (CONV) of 0.057 Gy/s. Materials and Methods A simple system, consisting of pBR322 plasmid DNA in 1× Tris-EDTA buffer, was initially employed for proton beam exposure. We then used formamidopyrimidine-DNA glycosylase (Fpg) enzymes. which convert oxidative base damages of oxidized purines to DNA strand breaks, to quantify DNA single strand breaks (SSBs) and double strand breaks (DSBs) by agarose gel electrophoresis. Results Our findings showed that the SSB induction rate (SSB per plasmid DNA/Gy) at UHDR and the induction of Fpg enzyme sensitive sites (ESS) were significantly reduced in UHDR compared to CONV. However, there was no significant difference in DSB induction and non-DSB cluster damages. Conclusions UHDR of a 59.5 MeV proton beam could reduce non-clustered, non-DSB damages, such as SSB and sparsely distributed ESS. However, this effect may not be significant in reducing lethal DNA damage that becomes apparent only in acute radiation effects of mammalian cells and in vivo studies.