Staining Properties of Selected Commercial Fluorescent Dyes Toward B- and Z-DNA

The properties of six commonly used, commercially available, fluorescent dyes were compared in staining right-handed B-DNA and left-handed Z-DNA. All showed different degree of fluorescence turn-on in the presence of B-DNA, but very little in the presence of Z-DNA. The optimal range of dye-DNA ratios of DNA was determined. While these dyes do not provide a turn-on type probe for Z-DNA, staining between B- and Z-DNA using dyes such as SYBR Green I was shown to be useful in tracking the kinetics of conformational changes between these two forms of DNA. Finally, SYBR Green I showed unique circular dichroism patterns in 4 M NaCl that change in the presence of double stranded DNA, both in the visible and UV range.

The new quinazoline derivative (N2-methyl-N4-[(thiophen-2-yl)methyl]quinazoline-2,4-diamine) vasodilates isolated mesenteric arteries through endothelium-independent mechanisms and has acute hypotensive effects in Wistar rats

During the screening of new N2,N4-disubstituted quinazoline 2,4-diamines as phosphodiesterase-5 inhibitors and pulmonary artery vasodilators, one N2-methyl-N4-[(thiophen-2-yl)methyl]quinazoline-2,4-diamine (compound 8) presented a greater selectivity for systemic than pulmonary vasculature. The present study aimed to characterize its vasorelaxant and hypotensive effects in Wistar rats. Vasorelaxant effects of compound 8 and underlying mechanisms were evaluated on isolated mesenteric arteries. Acute hypotensive effect was evaluated in anesthetized rats. Additionally, cell viability and cytochrome P450 (CYP) activities were studied in rat isolated hepatocytes. Nifedipine was used as a comparator. Compound 8 induced a strong vasorelaxant effect, similar to nifedipine. This was unaffected by endothelium removal but was decreased by inhibitors of guanylate cyclase (ODQ) and KCa channel (iberiotoxin). Compound 8 enhanced sodium nitroprusside-induced relaxation, but inhibited vasoconstriction evoked by α1-adrenergic receptor activation and extracellular Ca2+ influx via receptor-operated Ca2+ channels. Acute intravenous infusion of compound 8 (0.05 and 0.1 mg/kg) produced hypotension. It showed similar potency to nifedipine for lowering diastolic and mean arterial blood pressure, but less so for the effect on systolic blood pressure. Compound 8 had no effect on hepatocyte viability and CYP activities except at high concentration (10 μM) at which a weak inhibitory effect on CYP1A and 3A was observed. In conclusion, this study identified a N2-methyl-N4-[(thiophen-2-yl)methyl]quinazoline-2,4-diamine with a potent vasodilator effect on resistance vessels, leading to an acute hypotensive effect and a low risk of liver toxicity or drug-drug interactions. These vascular effects were mediated mainly through sGC/cGMP pathway, opening of KCa channels, and inhibition of calcium entry.

Platinum(IV) combo prodrugs containing cyclohexane-1R,2R-diamine, valproic acid, and perillic acid as a multiaction chemotherapeutic platform for colon cancer

The complex [PtCl2(cyclohexane-1R,2R-diamine)] has been combined in a Pt(IV) molecule with two different bioactive molecules (i.e., the histone deacetylase inhibitor 2-propylpentanoic acid or valproic acid, VPA, and the potential antimetastatic molecule 4-isopropenylcyclohexene-1-carboxylic acid or perillic acid, PA) in order to obtain a set of multiaction or multitarget antiproliferative agents. In addition to traditional thermal synthetic procedures, microwave-assisted heating was used to speed up their preparation. All Pt(IV) complexes showed antiproliferative activity on four human colon cancer cell lines (namely HCT116, HCT8, RKO and HT29) in the nanomolar range, considerably better than those of [PtCl2(cyclohexane-1R,2R-diamine)], VPA, PA, and the reference drug oxaliplatin. The synthesized complexes showed pro-apoptotic and pro-necrotic effects and the ability to induce cell cycle alterations. Moreover, the downregulation of histone deacetylase activity, leading to an increase in histone H3 and H4 levels, and the antimigratory activity, indicated by the reduction of the levels of matrix metalloproteinases MMP2 and MMP9, demonstrated the multiaction nature of the complexes, which showed biological properties similar to or better than those of VPA and PA, but at lower concentrations, probably due to the lipophilicity of the combo molecule that increases the intracellular concentration of the single components (i.e., [PtCl2(cyclohexane-1R,2R-diamine)], VPA and PA).

A Conformationally Restricted Gold(III) Complex Elicits Antiproliferative Activity in Cancer Cells

Diamine ligands are effective structural scaffolds for tuning the reactivity of transition-metal complexes for catalytic, materials, and phosphorescent applications and have been leveraged for biological use. In this work, we report the synthesis and characterization of a novel class of cyclometalated [C^N] Au(III) complexes bearing secondary diamines including a norbornane backbone, (2R,3S)-N2,N3-dibenzylbicyclo[2.2.1]heptane-2,3-diamine, or a cyclohexane backbone, (1R,2R)-N1,N2-dibenzylcyclohexane-1,2-diamine. X-ray crystallography confirms the square-planar geometry and chirality at nitrogen. The electronic character of the conformationally restricted norbornane backbone influences the electrochemical behavior with redox potentials of -0.8 to -1.1 V, atypical for Au(III) complexes. These compounds demonstrate promising anticancer activity, particularly, complex 1, which bears a benzylpyridine organogold framework, and supported by the bicyclic conformationally restricted diaminonorbornane, shows good potency in A2780 cells. We further show that a cellular response to 1 evokes reactive oxygen species (ROS) production and does not induce mitochondrial dysfunction. This class of complexes provides significant stability and reactivity for different applications in protein modification, catalysis, and therapeutics.

Structural, vibrational spectroscopy, molecular docking, DFT studies and antibacterial activity of (E)-N1-(3-chlorobenzylidene)benzene-1,4-diamine

In this work, (E)-N1-(3-chlorobenzylidene)benzene-1,4-diamine (CBD) compound was synthesized with good yield. The spectral studies were recorded by FT-IR, FT-Raman, NMR and UV-Vis to determine structural parameters. The geometrical parameters were optimized using DFT calculations at 6-311++G(d,p) basis set. The calculated structural parameters of the molecule were in line with the experimental data. The molecular orbitals of the compound were investigated through highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) analysis. The hyper conjugative interaction energy E(2) along with donor, acceptor electron densities (EDs) were determined by natural bond orbital (NBO) analysis. The molecular electrostatic potential (MEP), mulliken atomic charges, non-linear optical (NLO) properties and potential energy surface (PES) scan were also calculated. The 1H and 13C NMR chemical shifts calculated using Gauge invariant atomic orbital (GIAO) method were compared with the experimental NMR chemical shifts. Thermogravimetry (TG) and Differential Scanning Calorimetry (DSC) were carried out to characterise the thermal behaviour and stability of CBD molecule. In addition, PreADMET tool was also used to estimate ADME and Toxicity of CBD compound. The compound screened against four pathogens two gram positive and two gram negative had shown good anti-bacterial behaviour. The molecular docking studies executed against anti-bacterial target topoisomerase DNA gyrase enzyme (2XCT) emphasized good binding behaviour over the standard drug.Communicated by Ramaswamy H. Sarma.

Chiral 8-Amino-5,6,7,8-tetrahydroquinoline Derivatives in Metal Catalysts for the Asymmetric Transfer Hydrogenation of 1-Aryl Substituted-3,4-dihydroisoquinolines as Alkaloids Precursors

Chiral diamines based on an 8-amino-5,6,7,8-tetrahydroquinoline backbone, known as CAMPY (L1), or the 2-methyl substituted analogue Me-CAMPY (L2) were employed as novel ligands in Cp* metal complexes for the ATH of a series of substituted dihydroisoquinolines (DHIQs), known for being key intermediates in the synthesis of biologically active alkaloids. Different metal-based complexes were evaluated in this kind of reaction, rhodium catalysts, C3 and C4, proving most effective both in terms of reactivity and enantioselectivity. Although modest enantiomeric excess values were obtained (up to 69% ee in the case of substrate I), a satisfactory quantitative conversion was successfully fulfilled even in the case of the most demanding hindered substrates when La(OTf)₃ was used as beneficial additive, opening up the possibility for a rational design of novel chiral catalysts alternatives to the Noyori-Ikariya (arene)Ru(II)/TsDPEN catalyst.

Accelerated synthesis of phthalimide derivatives: Intrinsic reactivity of diamines towards phthalic anhydride evaluated by paper spray ionization mass spectrometry

RATIONALE

Paper spray (PS) is a simple and innovative ambient ionization technique for mass spectrometry (MS) analysis. Under PS-MS conditions, chemical reactions, which usually occur slowly on a bulk scale, are accelerated. Moreover, the formation of products and transient species can be easily monitored. In this manuscript, reactions between phthalic anhydride and diamines were conducted and monitored using a PS-MS platform. The reaction products (phthalimides) have many pharmaceutical applications, but their traditional syntheses can take hours under reflux, requiring laborious purification steps.

METHODS

In situ reactions were performed by dropping methanolic solutions of phthalic anhydride and diamines on a triangular paper. The analyses were achieved by positioning the triangle tip in front of the mass spectrometer entrance, whereas a metal clip was attached to the triangle base. After adding methanol to the paper, a high voltage was applied across the metal clip, and the mass spectra were acquired.

RESULTS

The intrinsic reactivity of alkyl and aromatic diamines was evaluated. The carbon chain remarkably influenced the reactivity of aliphatic diamines. For aryl diamines, the ortho isomer was the most reactive. Moreover, for aryl amines with electron-withdrawing substituents, no reaction was noticed.

CONCLUSIONS

Taking advantage of the unique characteristics of PS-MS, it was possible to investigate the intrinsic reactivity of model alkyl (ethylene versus propylene) and aryl (o-phenylene versus m-phenylene and p-phenylene) diamines towards phthalic anhydride. Some crucial parameters that affect the intrinsic reactivity of organic molecules, such as isomerism, intramolecular interaction, and conformation, were easily explored.

Molecular Design, Preparation, and Characterization of Fluoro-Containing Polyimide Ultrafine Fibrous Membranes with High Whiteness, High Thermal Stability, and Good Hydrophobicity

Polymeric ultrafine fibrous membranes (UFMs) with high thermal stability and high whiteness are highly desired in modern optoelectronic applications. A series of fluoro-containing polyimide (FPI) UFMs with high whiteness, good thermal stability, and good hydrophobicity were prepared via a one-step electrospinning procedure from the organo-soluble FPI resins derived from a fluoro-containing dianhydride, 4,4′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA), and various diamines containing either pendant trifluoromethyl (–CF3) groups or alicyclic units in the side chains. The obtained FPI UFMs, including FPI-1 from 6FDA and 3,5-diaminobenzotrifluoride (TFMDA), FPI-2 from 6FDA and 2′-trifluoromethyl-3,4′-oxydianiline (3FODA), FPI-3 from 6FDA and 1,4-bis[(4-amino-2-trifluoromethyl)phenoxy]benzene (6FAPB), FPI-4 from 4,4′-bis[(4-amino-2-trifluoromethyl)phenoxy]biphenyl (6FBAB), and FPI-5 from 6FDA and 4’-tert-butyl-cyclohexyl-3,5-diaminobenzoate (DABC) showed whiteness indices (WI) higher than 87.00 and optical reflectance values higher than 80% at the wavelength of 457 nm (R457), respectively. The FPI-5 UFM, especially, showed the highest WI of 92.88. Meanwhile, the prepared PI UFMs exhibited good hydrophobic features with water contact angles (WCA) higher than 105°. At last, the PI UFMs exhibited good thermal stability with glass transition temperatures (Tg) higher than 255 °C, and the 5% weight-loss temperatures (T5%) higher than 510 °C in nitrogen.

Histological and histochemical characteristics of lacrimal glands in beluga whales (Delphinapterus leucas)

The objective of this study was to describe the histological and histochemical characteristics of the lacrimal glands of beluga whales. The study was carried out on the formalin-fixed ocular globes from 96 carcasses of beluga whales found stranded in the St. Lawrence estuary in Quebec, Canada. Hematoxylin and eosin (H&E) stained slides from the eyes of each whale were examined for lacrimal glands. Histological description was done with H&E and Masson Trichrome (MT) stains. Period Acid-Schiff (PAS), Alcian blue (AB) pH 1.0 and 2.5, and High Iron Diamine (HID) stains were used for histochemical characterization of glycoproteins. Thirteen ocular samples from animals ranging from neonate to 48 y included sections of lacrimal glands. The H&E stain revealed a tubuloalveolar gland architecture, separated into lobules by dense connective tissue. Each lobule contained a mixture of acini and tubules with ductules. Small and large acini were composed of low and tall columnar cells, respectively. Acinar cells contained basophilic cytoplasmic granules. The ductules were lined with a bi-layered cuboidal-to-squamous epithelium. The MT stain highlighted the connective tissue separating ductules and acini. Large acini were positive for PAS and some small acini had patchy uptake. Positive staining for AB pH 1.0 and 2.5 was mainly seen in tall columnar cells as compared to small acini that had faint to no stain uptake. High Iron Diamine stain revealed 90% staining of all acinar cells, with 10% exhibiting a mixed blue-black tinge. It was concluded that the lacrimal glands of beluga whales have similar histological and histochemical findings to those of artiodactyla and carnivora orders.

Synthesis of DNA Duplexes Containing Site-Specific Interstrand Cross-Links via Sequential Reductive Amination Reactions Involving Diamine Linkers and Abasic Sites on Complementary Oligodeoxynucleotides

Interstrand DNA cross-links are important in biology, medicinal chemistry, and materials science. Accordingly, methods for the targeted installation of interstrand cross-links in DNA duplexes may be useful in diverse fields. Here, a simple procedure is reported for the preparation of DNA duplexes containing site-specific, chemically defined interstrand cross-links. The approach involves sequential reductive amination reactions between diamine linkers and two abasic (apurinic/apyrimidinic, AP) sites on complementary oligodeoxynucleotides. Use of the symmetrical triamine, tris(2-aminoethyl)amine, in this reaction sequence enabled the preparation of a cross-linked DNA duplex bearing a derivatizable aminoethyl group.

Discovery and optimization of cyclohexane-1,4-diamines as allosteric MALT1 inhibitors

Inhibition of mucosa-associated lymphoid tissue lymphoma translocation protein-1 (MALT1) is a promising strategy to modulate NF-κB signaling, with the potential to treat B-cell lymphoma and autoimmune diseases. We describe the discovery and optimization of (1s,4s)-N,N'-diaryl cyclohexane-1,4-diamines, a novel series of allosteric MALT1 inhibitors, resulting in compound 8 with single digit micromolar cell potency. X-ray analysis confirms that this compound binds to an induced allosteric site in MALT1. Compound 8 is highly selective and has an excellent in vivo rat PK profile with low clearance and high oral bioavailability, making it a promising lead for further optimization.

Overcoming Metastable CO2 Adsorption in a Bulky Diamine-Appended Metal-Organic Framework

Carbon capture at fossil fuel-fired power plants is a critical strategy to mitigate anthropogenic contributions to global warming, but widespread deployment of this technology is hindered by a lack of energy-efficient materials that can be optimized for CO2 capture from a specific flue gas. As a result of their tunable, step-shaped CO2 adsorption profiles, diamine-functionalized metal-organic frameworks (MOFs) of the form diamine-Mg2(dobpdc) (dobpdc4- = 4,4'-dioxidobiphenyl-3,3'-dicarboxylate) are among the most promising materials for carbon capture applications. Here, we present a detailed investigation of dmen-Mg2(dobpdc) (dmen = 1,2-diamino-2-methylpropane), one of only two MOFs with an adsorption step near the optimal pressure for CO2 capture from coal flue gas. While prior characterization suggested that this material only adsorbs CO2 to half capacity (0.5 CO2 per diamine) at 1 bar, we show that the half-capacity state is actually a metastable intermediate. Under appropriate conditions, the MOF adsorbs CO2 to full capacity, but conversion from the half-capacity structure happens on a very slow time scale, rendering it inaccessible in traditional adsorption measurements. Data from solid-state magic angle spinning nuclear magnetic resonance spectroscopy, coupled with van der Waals-corrected density functional theory, indicate that ammonium carbamate chains formed at half capacity and full capacity adopt opposing configurations, and the need to convert between these states likely dictates the sluggish post-half-capacity uptake. By use of the more symmetric parent framework Mg2(pc-dobpdc) (pc-dobpdc4- = 3,3'-dioxidobiphenyl-4,4'-dicarboxylate), the metastable trap can be avoided and the full CO2 capacity of dmen-Mg2(pc-dobpdc) accessed under conditions relevant for carbon capture from coal-fired power plants.

Photoinduced copper-catalysed asymmetric amidation via ligand cooperativity

The substitution of an alkyl electrophile by a nucleophile is a foundational reaction in organic chemistry that enables the efficient and convergent synthesis of organic molecules. Although there has been substantial recent progress in exploiting transition-metal catalysis to expand the scope of nucleophilic substitution reactions to include carbon nucleophiles1-4, there has been limited progress in corresponding reactions with nitrogen nucleophiles5-8. For many substitution reactions, the bond construction itself is not the only challenge, as there is a need to control stereochemistry at the same time. Here we describe a method for the enantioconvergent substitution of unactivated racemic alkyl electrophiles by a ubiquitous nitrogen-containing functional group, an amide. Our method uses a photoinduced catalyst system based on copper, an Earth-abundant metal. This process for asymmetric N-alkylation relies on three distinct ligands-a bisphosphine, a phenoxide and a chiral diamine. The ligands assemble in situ to form two distinct catalysts that act cooperatively: a copper/bisphosphine/phenoxide complex that serves as a photocatalyst, and a chiral copper/diamine complex that catalyses enantioselective C-N bond formation. Our study thus expands enantioselective N-substitution by alkyl electrophiles beyond activated electrophiles (those bearing at least one sp- or sp2-hybridized substituent on the carbon undergoing substitution)8-13 to include unactivated electrophiles.

Development of a SYBR Green-based real-time quantitative polymerase chain reaction assay to detect enzootic nasal tumor virus in goats

Enzootic nasal adenocarcinoma is a contagious respiratory disease in goats that is caused by the enzootic nasal tumor virus 2 (ENTV-2). In order to increase the number of available detection methods for ENTV-2, we developed a SYBR Green real-time polymerase chain reaction (SGrPCR) assay that targets the gag gene of ENTV-2. The low limit of detection of the assay was 3.68 × 10¹ copies/μL, a hundredfold more sensitive than conventional PCR. The melt curve showed a single sharp melt peak at 83°C, which indicated that there was no non-specific amplification or primer dimer formation. The intra-assay and inter-assay coefficients of variation were 1.58% and 1.82%, respectively. There was no cross-reactivity with closely related goat viruses (i.e., orf virus, peste des petits ruminants virus, goatpox virus, foot-and-mouth disease virus) and endogenous retroviruses. In conclusion, the SGrPCR assay is specific for the gag gene of ENTV-2 and provides a rapid and sensitive approach for detecting ENTV-2 in clinical samples.

Validation of SYBR green I based closed-tube loop-mediated isothermal amplification (LAMP) assay for diagnosis of knowlesi malaria

BACKGROUND

As an alternative to PCR methods, LAMP is increasingly being used in the field of molecular diagnostics. Under isothermal conditions at 65 °C, the entire procedure takes approximately 30 min to complete. In this study, we establish a sensitive and visualized LAMP method in a closed-tube system for the detection of Plasmodium knowlesi.

METHODS

A total of 71 malaria microscopy positive blood samples collected in blood spots were obtained from the Sarawak State Health Department. Using 18s rRNA as the target gene, nested PCR and SYBR green I LAMP assay were performed following the DNA extraction. The colour changes of LAMP end products were observed by naked eyes.

RESULTS

LAMP assay demonstrated a detection limit of 10 copies/µL in comparison with 100 copies/µL nested PCR. Of 71 P. knowlesi blood samples collected, LAMP detected 69 microscopy-positive samples. LAMP exhibited higher sensitivity than nested PCR assay. The SYBR green I LAMP assay was 97.1% sensitive (95% CI 90.2-99.7%) and 100% specific (95% CI 83.2-100%). Without opening the cap, incorporation of SYBR green I into the inner cap of the tube enabled the direct visualization of results upon completion of amplification. The positives instantaneously turned green while the negatives remained orange.

CONCLUSIONS

These results indicate that SYBR green I LAMP assay is a convenient diagnosis tool for the detection of P. knowlesi in remote settings.

Diffusivelike Motions in a Solvent-Free Protein-Polymer Hybrid

The interaction between proteins and hydration water stabilizes protein structure and promotes functional dynamics, with water translational motions enabling protein flexibility. Engineered solvent-free protein-polymer hybrids have been shown to preserve protein structure, function, and dynamics. Here, we used neutron scattering, protein and polymer perdeuteration, and molecular dynamics simulations to explore how a polymer dynamically replaces water. Even though relaxation rates and vibrational properties are strongly modified in polymer coated compared to hydrated proteins, liquidlike polymer dynamics appear to plasticize the conjugated protein in a qualitatively similar way as do hydration-water translational motions.

Simple In-liquid Staining of Microbial Cells for Flow Cytometry Quantification of the Microbial Population in Marine Subseafloor Sediments

Microbial cell counting provides essential information for the study of cell abundance profiles and biogeochemical interactions with the surrounding environments. However, it often requires labor-intensive and time-consuming processes, particularly for subseafloor sediment samples, in which non-cell particles are abundant. We developed a rapid and straightforward method for staining microbial intracellular DNA by SYBR Green I (SYBR-I) to enumerate cells by flow cytometry (FCM). We initially examined the efficiency of microbial cell staining at various dye/sediment ratios (volume ratio of SYBR-I/sediment [vSYBR/vSed]). Non-cell particles in sediment strongly and preferentially adsorbed SYBR-I dye, resulting in the unsuccessful staining of microbial cells when an insufficient ratio (<1.63 vSYBR/vSed) of SYBR-I dye was present per volume of sediment. SYBR-I dye at an abundance of 10 vSYBR/vSed successfully and stably stained microbial cells in green fluorescence, while the fluorescent color of non-cell particles red-shifted to yellow-orange with the overaccumulation of SYBR-I dye. A low vSYBR/vSed ratio was quickly recognized by a colorless supernatant after centrifugation. At the appropriate vSYBR/vSed ratio, FCM-measured cell concentrations in subseafloor sediments were consistently similar to microscopy counts (>106 cells cm-3). Samples with low cell abundance (<105 cells cm-3) still require cell separation. This modified staining allows us to efficiently process and perform the microbial cell counting of sediment samples to a depth of a few hundred meters below the seafloor with a higher throughput and capability to scale up than procedures employing microscopy-based observations.

DNA-Binding Capabilities and Anticancer Activities of Ruthenium(II) Cymene Complexes with (Poly)cyclic Aromatic Diamine Ligands

Ruthenium(II) arene complexes of the general formula [RuCl(η⁶-p-cymene)(diamine)]PF₆ (diamine = 1,2-diaminobenzene (1), 2,3-diaminonaphthalene (2), 9,10-diaminophenanthrene (3), 2,3-diaminophenazine (4), and 1,2-diaminoanthraquinone (5) were synthesized. Chloro/aqua exchange was evaluated experimentally for complexes 1 and 2. The exchange process was investigated theoretically for all complexes, revealing relatively fast exchange with no significant influence from the polycyclic aromatic diamines. The calf thymus DNA (CT-DNA) binding of the complexes increased dramatically upon extending the aromatic component of the diamines, as evaluated by changes in absorption spectra upon titration with different concentrations of CT-DNA. An intercalation binding mode was established for the complexes using the increase in the relative viscosity of the CT-DNA following addition of complexes 1 and 2. Theoretical studies showed strong preference for replacement of water by guanine for all the complexes, and relatively strong Ru-N_guanine bonds. The plane of the aromatic systems can assume angles that support non-classical interactions with the DNA and covalent binding, leading to higher binding affinities. The ruthenium arenes illustrated in this study have promising anticancer activities, with the half maximal inhibitory concentration (IC₅₀) values comparable to or better than cisplatin against three cell lines.

Fluorescent Probe for Ag+ Detection Using SYBR GREEN I and C-C Mismatch

Among heavy metals silver ions (Ag⁺) severely impact water, the environment and have serious side effects on human health. This article proposes a facile and ultrasensitive fluorescent probe for the detection of Ag⁺ ions using SYBR Green I (SGI) and cytosine-rich (C-rich) silver-specific oligonucleotide (SSO). Maximum fluorescent intensities with the highest sensitivity were obtained using a 0.61 dye/SSO base ratio (DBR). The established sensing principle using the optimized parameters for bath temperature, SSO concentration, DBR, ionic strength, pH, reaction time, incubation duration and temperature effect achieved a sensitive limit of detection of 59.9 nM for silver ions (calculated through 3σ, n = 11) with a linear working range of 100–1000 nM and 0.997 R². The total time for one assay is below 10 min; The relative standard derivation for ten repeated measurements is 8.6%. No blatant interferences were observed in the selectivity test when fluorescent probe is evaluated by investigating the effects of 11 common interference factors in the aqueous matrix. In extreme cases, three false-negative factors were observed, including calcium hardness, magnesium hardness, and hypochlorite. The recovery ratios were within the range of 79~110% for three types of diluted water.

Visualizing, quantifying, and manipulating mitochondrial DNA in vivo

Mitochondrial DNA (mtDNA) encodes proteins and RNAs that support the functions of mitochondria and thereby numerous physiological processes. Mutations of mtDNA can cause mitochondrial diseases and are implicated in aging. The mtDNA within cells is organized into nucleoids within the mitochondrial matrix, but how mtDNA nucleoids are formed and regulated within cells remains incompletely resolved. Visualization of mtDNA within cells is a powerful means by which mechanistic insight can be gained. Manipulation of the amount and sequence of mtDNA within cells is important experimentally and for developing therapeutic interventions to treat mitochondrial disease. This review details recent developments and opportunities for improvements in the experimental tools and techniques that can be used to visualize, quantify, and manipulate the properties of mtDNA within cells.

Keggin-type Heteropolyacids-Catalyzed Selective Hydrothermal Oxidation of Microalgae for Low Nitrogen Biofuel Production

Hydrothermal liquefaction (HTL) of microalgae for biofuel production is suffering from low bio-oil yield and high heteroatomic compositions owing to their low efficiency and selectivity to hydrolysis of cellular compounds. Hereby we report Keggin-type (Mo-V-P) heteropolyacids (HPAs)-catalyzed HTL of microalgae for efficient low-nitrogen biocrude production. The increases of reaction temperature, reaction time, and vanadium substitution degrees of HPAs are favorable to biocrude yield initially, whereas a significant decrease of biocrude yield is observed owing to the enhanced oxidation of carbohydrates above the optimum reaction conditions. The maximum biocrude yield of HPAs-catalyzed HTL of microalgae is 29.95 % at reaction temperature of 300 °C, reaction time of 2 h, and 5 wt% of HPA-4, which is about 19.66 % higher than that of control with 71.17 % less N-containing compounds, including 1,3-propanediamine, 1-pentanamine, and 2, 2'-heptamethylene-di-2-imidazoline than that of control. This work reveals that HPAs with Brønsted acidity and reversible redox properties are capable of both enhancing biocrude production via catalyzing the hydrolysis of cellular compounds and reducing their nitrogen content through avoiding the Maillard reactions between the intermediates of hydrolysis of carbohydrates and proteins. HPAs-catalyzed HTL is an efficient strategy to produce low N-containing biofuels, possibly paving the way of their direct use in modern motors.

Antibacterial Functions and Proposed Modes of Action of Novel 1,2,3,4-Tetrahydro-β-carboline Derivatives that Possess an Attractive 1,3-Diaminopropan-2-ol Pattern against Rice Bacterial Blight, Kiwifruit Bacterial Canker, and Citrus Bacterial Canker

In recent years, naturally occurring tetrahydro-β-carboline (THC) alkaloids and their derivatives have been of biological interest. However, few studies and developments have reported the use of such structures in managing plant bacterial diseases. Herein, an array of novel THC derivatives containing an attractive 1,3-diaminopropan-2-ol pattern were prepared to evaluate the antiphytopathogen activity in vitro and in vivo and explore innovative antibacterial frameworks. Notably, target compounds exhibited excellent activities against three rebellious phytopathogens, namely, Pseudomonas syringae pv. actinidiae (Psa), Xanthomonas axonopodis pv. citri, and Xanthomonas oryzae pv. oryzae, at related optimal EC₅₀ values of 2.39 (II₉), 2.06 (I₂₃), and 1.69 (II₉) μg/mL, respectively. These effects were superior to those of the parent structure 1,2,3,4-THC and positive controls. In vivo assays showed that II₉ exhibited excellent control efficiencies of 51.89 and 65.45% at 200 μg/mL against rice bacterial blight and kiwifruit bacterial canker, respectively, and I₂₃ substantially relieved the citrus canker on the leaves. Antibacterial mechanisms indicated that these THC compounds could induce the increment of reactive oxygen species and subsequently endow the tested bacteria with distinct apoptotic behavior. In addition, II₉ could alleviate the hypersensitive response and pathogenicity of Psa. Overall, these simple THC derivatives can be further developed as versatile antibacterial agents.

Heteroarylureas with fused bicyclic diamine cores as inhibitors of fatty acid amide hydrolase

A series of mechanism-based heteroaryl urea fatty acid amide hydrolase (FAAH) inhibitors with fused bicyclic diamine cores is described. In contrast to compounds built around a piperazine core, most of the fused bicyclic diamine bearing analogs prepared exhibited greater potency against rFAAH than the human enzyme. Several compounds equipotent against both species were identified and profiled in vivo.

Palladium (II)-Salan Complexes as Catalysts for Suzuki-Miyaura C-C Cross-Coupling in Water and Air. Effect of the Various Bridging Units within the Diamine Moieties on the Catalytic Performance

Water-soluble salan ligands were synthesized by hydrogenation and subsequent sulfonation of salens (N,N'-bis(slicylidene)ethylenediamine and analogues) with various bridging units (linkers) connecting the nitrogen atoms. Pd (II) complexes were obtained in reactions of sulfosalans and [PdCl₄]^2-. Characterization of the ligands and complexes included extensive X-ray diffraction studies, too. The Pd (II) complexes proved highly active catalysts of the Suzuki-Miyaura reaction of aryl halides and arylboronic acid derivatives at 80 °C in water and air. A comparative study of the Pd (II)-sulfosalan catalysts showed that the catalytic activity largely increased with increasing linker length and with increasing steric congestion around the N donor atoms of the ligands; the highest specific activity was 40,000 (mol substrate) (mol catalyst × h)^-1. The substrate scope was explored with the use of the two most active catalysts, containing 1,4-butylene and 1,2-diphenylethylene linkers, respectively.

Immobilization of β-Galactosidase From Aspergillus oryzae on Electrospun Gelatin Nanofiber Mats for the Production of Galactooligosaccharides

Two simple and easily reproducible methods for the immobilization of β-galactosidase (β-gal) from Aspergillus oryzae on electrospun gelatin nanofiber mats (GFM) were developed. The process was optimized regarding the electrospinning solvent system and the subsequent cross-linking of GFM in order to increase their stability in water. β-Gal was covalently immobilized on activated gelatin nanofiber mats with hexamethylenediamine (HMDA) as a bifunctional linker and secondly via entrapment into the gelatin nanofibers during the electrospinning process (suspension electrospinning). Optimal immobilization parameters for covalent immobilization were determined to be at pH 7.5, 40 °C, β-gal concentration of 1 mg/mL and immobilization time of 24.5 h. For suspension electrospinning, the optimal immobilization parameters were identified at pH 4.5 and β-gal concentration of 0.027 wt.% in the electrospinning solution. The pH and temperature optima of immobilized β-gal shifted from 30 °C, pH 4.5 (free enzyme) to pH 3.5, 50 °C (covalent immobilization) and pH 3.5, 40 °C (suspension electrospinning). Striking differences in the Michaelis constant (KM) of immobilized β-gal compared with free enzyme were observed with a reduction of KM up to 50% for immobilized enzyme. The maximum velocity (vmax) of immobilization by suspension electrospinning was almost 20 times higher than that of covalent immobilization. The maximum GOS yield for free β-gal was found to be 27.7% and 31% for immobilized β-gal.

Stereodivergent Synthesis of Camphor-Derived Diamines and Their Application as Thiourea Organocatalysts

A series of 18 regio- and stereo-chemically diverse chiral non-racemic 1,2-, 1,3-, and 1,4-diamines have been synthesized from commercial (1S)-(+)-ketopinic acid and (1S)-(+)-10-camphorsulfonic acid. The structures of the diamines are all based on the d-(+)-camphor scaffold and feature isomeric diversity in terms of regioisomeric attachment of the primary and the tertiary amine function and the exo/endo-isomerism. Diamines were transformed into the corresponding noncovalent bifunctional thiourea organocatalysts, which have been evaluated for catalytic activity in the conjugative addition of 1,3-dicarbonyl nucleophiles (dimethyl malonate, acetylacetone, and dibenzoylmethane) to trans-β-nitrostyrene. The highest enantioselectivity was achieved in the reaction with acetylacetone as nucleophile using endo-1,3-diamine derived catalyst 52 (91.5:8.5 er). All new organocatalysts 48-63 have been fully characterized. The structures and the absolute configurations of eight intermediates and thiourea derivative 52 were also determined by X-ray diffraction.

Multiplex real-time SYBR Green I PCR assays for simultaneous detection of 15 common enteric pathogens in stool samples

Diarrheal diseases account for more than 50% of foodborne diseases worldwide, the majority of which occur in infants and young children. The traditional bacterial detection method is complex and time-consuming; therefore, it is necessary to establish a rapid and convenient detection method that can detect multiple pathogens simultaneously. In this study, we developed a set of five multiplex real-time SYBR Green I PCR assays to simultaneously detect 15 common enteric pathogens based on the Homo-Tag Assisted Non-Dimer system. These assays effectively reduced primer-dimer formation and improved the stability, uniformity, and amplification efficiency of multiplex PCR. The detection limit of the multiplex SYBR Green I PCR system was approximately 10⁴-10⁶ CFU/mL for stool specimens. Furthermore, we vitrified heat-unstable components on the cap of a reaction tube, showing that Taq DNA polymerase, dNTPs, primers, and SYBR Green I remained stable at 25 °C. In summary, we developed multiplex SYBR Green I PCR assays that can simultaneously detect 15 enteric pathogens. This method is comprehensive, rapid, inexpensive, accurate, and simple and displays high specificity.

Development of a duplex SYBR GreenⅠ based real-time PCR assay for detection of porcine epidemic diarrhea virus and porcine bocavirus3/4/5

The duplex real-time PCR assay based on SYBR Green І was developed for detection of porcine epidemic diarrhea virus (PEDV) and porcine bocavirus (PBoV) 3/4/5 genotypes simultaneously. Two pairs of specific primers were designed targeting the N gene sequence of PEDV and VP1 gene sequence of PBoV3/4/5. PEDV and PBoV3/4/5 could be distinguished by their different melting temperatures (Tm) in one sample. The Tm value of PEDV was 83.5 °C, and the Tm value of PBoV3/4/5 was 78.5 °C, while other swine pathogens showed no specific melting peaks. The detection limits of this assay were 10 copies/μL for both PEDV and PBoV3/4/5. A total of sixty-three intestinal tissue samples were collected from piglets suffering from diarrhea, and the viral nucleic acids detected and identified by the real-time PCR assay and conventional PCR assay. The duplex real-time PCR detection results showed that the prevalence of PEDV and PBoV3/4/5 was 85.7% and 46%, respectively, and the co-infection rate of the two viruses was 28.6%. These results indicated that this duplex real-time PCR assay was a sensitive, specific and reproducible method for differentiating PEDV and PBoV3/4/5 or their co-infection.

A light-triggerable formulation to control the stability of pro-angiogenic transcription factor hypoxia inducible factor-1α (HIF-1α)

The control of vascular remodeling mediated by transcription factor HIF-1α is critical in the treatment of several diseases including cancer, retinopathies, chronic wounds, and ischemic heart disease, among others. Gene silencing using a small interfering RNA (siRNA) is a promising therapeutic strategy to regulate HIF-1α; however, the delivery systems developed so far have limited endothelial targeting and efficiency. Herein, we have synthesized a light-triggerable polymeric nanoparticle (NP) library composed of 110 formulations which showed variable morphology, charge and disassembly rates after UV exposure. More than 35% of the formulations of the library were more efficient in gene knockdown than the siRNA delivered by a commercial transfection agent (lipofectamine RNAiMAX). The most efficient siRNA delivery formulations were tested against different cell types to identify one with preferential targeting to endothelial cells. Using a two-step methodology, we have identified a formulation that shows exquisite targeting to endothelial cells and is able to deliver more efficiently the siRNA that modulates HIF-1α than commercial transfection agents. Overall, the strategy reported here increases the specificity for tissue regulation and the efficiency for the intracellular delivery of siRNAs.

Charge Retention/Charge Depletion in ESI-MS: Theoretical Rationale

Gas phase modification in ESI-MS can significantly alter the charge state distribution of small peptides and proteins. The preceding paper presented a systematic experimental study on this topic using Substance P and proposed a charge retention/charge depletion mechanism, explaining different gas- and liquid-phase modifications [Thinius et al. J. Am. Soc. Mass Spec. 2020, 10.1021/jasms.9b00044]. In this work, we aim to support this rational by theoretical investigations on the proton transfer processes from (multiply) charged analytes toward solvent clusters. As model systems we use small (di)amines as analytes and methanol (MeOH) and acetonitrile (ACN) as gas phase modifiers. The calculations are supported by a set of experiments using (di)amines, to bridge the gap between the present model system and Substance P used in the preceding study. Upon calculation of the thermochemical stability as well as the proton transfer pathways, we find that both ACN and MeOH form stable adduct clusters at the protonation site. MeOH can form large clusters through a chain of H-bridges, eventually lowering the barriers for proton transfer to an extent that charge transfer from the analyte to the MeOH cluster becomes feasible. ACN, however, cannot form H-bridged structures due to its aprotic nature. Hence, the charge is retained at the original protonation site, i.e., the analyte. The investigation confirms the proposed charge retention/charge depletion model. Thus, adding aprotic solvent vapors to the gas phase of an ESI source more likely yields higher charge states than using protic compounds.

Three-Component Reaction of Diamines with Triethyl Orthoformate and Diethyl Phosphite and Anti-Proliferative and Antiosteoporotic Activities of the Products

A three-component reaction between diamines (diaminobenzenes, diaminocyclohexanes, and piperazines), triethyl orthoformate, and diethyl phosphite was studied in some detail. In the case of 1,3- and 1,4-diamines and piperazines, products of the substitution of two amino moieties—the corresponding tetraphosphonic acids—were obtained. In the cases of 1,2-diaminobenzene, 1,2-diaminocyclohexanes and 1,2-diaminocyclohexenes, only one amino group reacted. This is most likely the result of the formation of hydrogen bonding between the phosphonate oxygen and a hydrogen of the adjacent amino group, which caused a decrease in the reactivity of the amino group. Most of the obtained compounds inhibited the proliferation of RAW 264.7 macrophages, PC-3 human prostate cancer cells, and MCF-7 human breast cancer cells, with 1, trans-7, and 16 showing broad nonspecific activity, which makes these compounds especially interesting in the context of anti-osteolytic treatment and the blocking of interactions and mutual activation of osteoclasts and tumor metastatic cells. These compounds exhibit similar activity to zoledronic acid and higher activity than incadronic acid, which were used as controls. However, studies of sheep with induced osteoporosis carried out with compound trans-7 did not support this assumption.

Carbon quantum dot-AgOH colloid fluorescent probe for selective detection of biothiols based on the inner filter effect

Here, we present a selective and sensitive fluorescent probe for the detection and distinction of biothiols, such as glutathione (GSH) and cysteine (Cys). The adsorbance of Cys onto the surface of AgOH colloid could result in enhanced absorbance from 250 to 400 nm in the UV-vis absorption spectrum, while the addition of GSH could dissolve the AgOH colloid resulting in no change in the UV-vis absorption spectrum. Utilizing these different phenomena, two fluorescent probes were established based on the inner filter effect (IFE). The first probe, the "CDs-AgOH colloid" fluorescent probe, was used to quantitatively analyze Cys over a linear concentration range from 33 to 317 μM and a detection limit of 7.2 μM. The second probe, the "CDs-AgOH colloid-Cys" fluorescent probe, was used to quantitatively analyze GSH, with a detection limit down to 3.6 μM, and a linear range of detection of approximately 16.7 to 100 μM. The fluorescent probes were successfully applied for the detection of GSH in a fetal bovine serum (FBS) sample. Based on these results, IFE is considered to be an effective way to distinguish GSH and Cys.

Regioselective and Stereodivergent Synthesis of Enantiomerically Pure Vic-Diamines from Chiral β-Amino Alcohols with 2-Pyridyl and 6-(2,2'-Bipyridyl) Moieties

In this report, we describe the synthetic elaboration of the easily available enantiomerically pure β-amino alcohols. Attempted direct substitution of the hydroxyl group by azido-functionality in the Mitsunobu reaction with hydrazoic acid was inefficient or led to a diastereomeric mixture. These outcomes resulted from the participation of aziridines. Intentionally performed internal Mitsunobu reaction of β-amino alcohols gave eight chiral aziridines in 45-82% yield. The structural and configuration identity of products was confirmed by NMR data compared to the DFT calculated GIAO values. For 1,2,3-trisubstituted aziridines slow configurational inversion at the endocyclic nitrogen atom was observed by NMR at room temperature. Moreover, when aziridine was titrated with Zn(OAc)₂ under NMR control, only one of two N-epimers directly participated in complexation. The aziridines underwent ring opening with HN₃ to form the corresponding azido amines as single regio- and diastereomers in 90-97% yield. Different results were obtained for 1,2-disubstituted and 1,2,3-trisubstituted aziridines. For the later aziridines ring closure and ring opening occurred at different carbon stereocenters, thus yielding products with two inverted configurations, compared to the starting amino alcohol. The 1,2-disubstituted aziridines produced azido amines of the same configuration as the starting β-amino alcohols. To obtain a complete series of diastereomeric vic-diamines, we converted the amino alcohols into cyclic sulfamidates, which reacted with sodium azide in S_N2 reaction (25-58% overall yield). The azides obtained either way underwent the Staudinger reduction, giving a series of six new chiral vic-diamines of defined stereochemistries.

Staining Nucleic Acids

This introduction describes the features and uses of ethidium bromide, methylene blue, and SYBR dyes for staining nucleic acids.

One-step microwave synthesis of N,S co-doped carbon dots from 1,6-hexanediamine dihydrochloride for cell imaging and ion detection

As a new member of the fluorescent carbon nanomaterial family, carbon dots (CDs) not only have outstanding photoluminescence properties and small size characteristics, but also contain favourable low cytotoxicity and biocompatibility, which could be the best choice to detect of ions to replace quantum dots for ions detection. Here, the N,S co-doped carbon dots (N/S-CDs) was synthesized by one-step microwave using 1,6-hexanediamine dihydrochloride and dimethyl sulfoxide as precursors, and their morphology and structure were characterized by TEM, XRD, XPS and FTIR. The optimal emission wavelength of the CDs was 512 nm with green fluorescence, and was red-shifted gradually as the excitation wavelength aggrandized. The synthesized CDs owned a well quantum yield of 24 %. It was further applied for the detection of MnO₄^- and Cr₂O₇^2- with an excellent detection limit of 0.34 μM and 0.23μM, respectively. Cr₂O₇^2- did not influence the N/S-CDs PL response of MnO₄^- in the presence of excessive Pb²⁺. Moreover, the obtained N/S-CDs demonstrated preeminent biocompatibility and could be resoundingly applied for cellular imaging.

The Synthesis and Functional Study of Multicolor Nitrogen-Doped Carbon Dots for Live Cell Nuclear Imaging

The nitrogen-doped carbon dots (N-CQDs) were synthesized by citric acid as a raw material and propylene diamine as a passivation agent. Structure, optical properties and biocompatibility of N-CQDs were analyzed. It was found that the N-CQDs possessed concentration-dependent, multicolor photoluminescence and low toxicity. As demonstrated in the imaging of bioluminescence, by adjusting the concentration of N-CQDs, the cell imaging effect can be adjusted. The internalized N-CQDs were concentrated in the nucleus. A novel tool for studying the nuclear changes during the cell cycle was developed.

The Application of Reversible Intramolecular Sulfonamide Ligation to Modulate Reactivity in Organometallic Ruthenium(II) Diamine Complexes

Metallation of biomacromolecular species forms the basis for the anticancer activity of many metallodrugs. A major limitation of these compounds is that their reactivity is indiscriminate and can, in principle, occur in healthy tissue as well as cancerous tissue, potentially leading to side effects in vivo. Here we present pH-dependent intramolecular coordination of an arene-tethered sulfonamide functionality in organometallic ruthenium(II) ethylenediamine complexes as a route to controlling the coordination environment about the central metal atom. Through variation of the sulfonamide R group and the length of the tether linking it to the arene ligand the acidity of the sulfonamide NH group, and hence the pH-region over which regulation of metal coordination occurs, can be modulated. Intramolecular sulfonamide ligation controlled the reactivity of complex 4 within the physiologically relevant pH-region, rendering it more reactive towards 5ʹ-GMP in mildly acidic pH-conditions typical of tumour tissue compared to the mildly alkaline pH-conditions typical of healthy tissue. However, the activation of 4 by ring-opening of the chelate was found to be a slow process relative to the timescale of typical cell culture assays and members of this series of complexes were found not to be cytotoxic towards the HT-29 cell line. These complexes provide the basis for the development of analogues of increased potency where intramolecular sulfonamide ligation regulates reactivity and therefore cytotoxicity in a pH-dependent, and potentially, tissue-dependent manner.

Rationally designed magnetic poly(catechol-hexanediamine) particles for bacteria removal and on-demand biofilm eradication

In this study, we proposed a green, facile and low-cost approach for the fabrication of multifunctional particles with robust bacteria removal capability and on-demand biofilm eradication activity. Based on mussel-inspired coating of catechol and hexanediamine on Fe₃O₄ in aqueous solution, magnetic poly(catechol-hexanediamine) particles (Fe₃O₄@HDA) were prepared successfully in 1 h, at room temperature. Microbiological experiments demonstrated the Fe₃O₄@HDA particles could capture bacteria in water efficiently. Meanwhile, with an integration of magnetic response property and near-infrared-triggered photothermal bactericidal activity, the Fe₃O₄@HDA particles showed a high potential for biofilm targeting and in-situ eradication. We believe that the rationally designed magnetic poly(catechol-hexanediamine) particles could extend the applications of smart antimicrobial agents to industrial fields such as water disinfection and biofouling clean-up.

Albumin Broadens the Antibacterial Capabilities of Nonantibiotic Small Molecule-Capped Gold Nanoparticles

Nonantibiotic small molecule-modified gold nanoparticles (Au NPs) show great potential as an alternative for commercial antibiotics, yet their narrow antibacterial spectrum hinders the wide application in clinics. We observe that Au NPs cofunctionalized with both bovine serum albumin (BSA) and 4,6-diamino-2-pyrimidinethiol (DAPT) can generate conjugates (Au_DAPT_BSA) with progressive antimicrobial activities, including decreased minimal inhibitory concentration against Gram-negative bacteria and extended antibacterial spectrum against Gram-positive bacteria compared with DAPT-capped Au NPs (Au_DAPT). Au_DAPT_BSA induces no drug resistance and can significantly decrease the number of bacteria in the biofilms formed by Pseudomonas aeruginosa and Staphylococcus aureus. In addition, Au_DAPT_BSA exhibit in vivo healing efficiency for mice with subcutaneous abscesses caused by clinically isolated, multidrug resistant Escherichia coli or S. aureus without inducing detectable toxicity to the mammalian cells/animals. Our findings provide a new strategy for strengthening nanomaterial-based bactericides such as Au NPs, especially against drug-resistant bacterial infections.

OH degraded 2-Methylisoborneol during the removal of algae-laden water in a drinking water treatment system: Comparison with ClO2

The growth of algae in water and the taste and odour compounds produced by algal metabolism present a threat to water quality, public health and aquatic ecosystems and cannot be effectively removed by conventional water treatment processes. In this paper, a hydroxyl radical (OH)-based drinking water treatment system (DWTS) with a capacity of 480 m³ per day was built in the Xinglin water plant, Xiamen, China. With pretreatment at 0.88 mg L^-1, sand filtration, and disinfection at 0.31 mg L^-1 during the conveyance of algae-laden water within only 9.8 s, OH removed all five kinds of algae, with a total content of 35,180 cells mL^-1, while ClO₂ treatment left live and dead algae at 7150 cells mL^-1, which would be transported into the pipe networks for the drinking water supply. Meanwhile, OH degraded 2-Methylisoborneol (2-MIB) from 175 to 4.4 ng L^-1, which was below the Chinese standard of 10 ng L^-1, while ClO₂ degraded 2-MIB only to 155 ng L^-1. Based on analyses of the mass spectra database, OH could mineralize 2-MIB by opening the ring structures of 2,2-dimethyl-1,3-cyclopentanedione and 2-methyl-cyclohexenecarboxaldehyde to produce small-molecule compounds. After OH pretreatment and OH disinfection, all water quality and disinfection by-product indexes met the Chinese Sanitary Standards for Drinking Water. Therefore, OH advanced oxidation produced using strong ionization discharge could be practically applied for the degradation of 2-MIB during the treatment of algae-laden water in the OH DWTS.

Exploring the activity of polyamine analogues on polyamine and spermine oxidase: methoctramine, a potent and selective inhibitor of polyamine oxidase

Fourteen polyamine analogues, asymmetric or symmetric substituted spermine (1-9) or methoctramine (10-14) analogues, were evaluated as potential inhibitors or substrates of two enzymes of the polyamine catabolic pathway, spermine oxidase (SMOX) and acetylpolyamine oxidase (PAOX). Compound 2 turned out to be the best substrate for PAOX, having the highest affinity and catalytic efficiency with respect to its physiological substrates. Methoctramine (10), a well-known muscarinic M2 receptor antagonist, emerged as the most potent competitive PAOX inhibitor known so far (Ki = 10 nM), endowed with very good selectivity compared with SMOX (Ki=1.2 μM vs SMOX). The efficacy of methoctramine in inhibiting PAOX activity was confirmed in the HT22 cell line. Methoctramine is a very promising tool in the design of drugs targeting the polyamine catabolism pathway, both to understand the physio-pathological role of PAOX vs SMOX and for pharmacological applications, being the polyamine pathway involved in various pathologies.

Novel Convenient Approach to the Solid-Phase Synthesis of Oligonucleotide Conjugates

A novel and convenient approach for the solid-phase 5'-functionalization of oligonucleotides is proposed in this article. The approach is based on the activation of free 5'-hydroxyl of polymer support-bound protected oligonucleotides by N,N'-disuccinimidyl carbonate followed by interaction with amino-containing ligands. Novel amino-containing derivatives of closo-dodecaborate, estrone, cholesterol, and α-tocopherol were specially prepared. A wide range of oligonucleotide conjugates bearing closo-dodecaborate, short peptide, pyrene, lipophilic residues (cholesterol, α-tocopherol, folate, estrone), aliphatic diamines, and propargylamine were synthesized and characterized to demonstrate the versatility of the approach. The developed method is suitable for the conjugate synthesis of oligonucleotides of different types (ribo-, deoxyribo-, 2'-O-methylribo-, and others).

Reaction-Based, Fluorescent Film Deposition from Dopamine and a Diamine-Tethered, Bis-Resorcinol Coupler

The reaction-based deposition on various surfaces of an all-organic fluorescent coating is reported here, involving autoxidation of 2 mM dopamine in carbonate buffer at pH 9.0, in the presence of a 1 mM diamine–resorcinol coupler (Bis–Res) prepared from 2,4-dihydroxybenzaldehyde and hexamethylenediamine (HMDA). Spectral analysis of the films coupled with an LC-MS investigation of the yellow fluorescent mixture was compatible with the formation and deposition of HMDA-linked methanobenzofuroazocinone fluorophores. Both the emission properties and hydrophobicity of the film were abated in a reversible manner following exposure to acid vapors. These results provide an entry to efficient and practical fluorescent coating methodologies based on in situ generation and the deposition of wet adhesive, as well as fluorescent materials combining a strongly emitting fluorophore with the film-forming properties of long chain diamines.

In vitro testing of a first-in-class tri-alkylnorspermidine-biaryl antibiotic in an anti-biofilm silicone coating

Biofilm-related infection is among the worst complication to prosthetic joint replacement procedures; once established on the implant surface, biofilms show strong recalcitrance to clinical antibiotic therapy, frequently requiring costly revision procedures and prolonged systemic antibiotics for their removal. A well-designed active release coating might assist host immunity in clearing bacterial contaminants within the narrow perioperative window and ultimately prevent microbial colonization of the joint prosthesis. A first-in-class compound (CZ-01127) was tested as the active release agent in a silicone (Si) coating using an in vitro dynamic flow model of surgical site contamination and compared with analogous coatings containing clinical gold-standard antibiotics vancomycin and gentamicin; the CZ-01127 coating outperformed both vancomycin and gentamicin coatings and was the only to decrease the methicillin-resistant Staphylococcus aureus (MRSA) inocula below detectable limits for the first 3 days. The antimicrobial activity of CZ-01127, and for comparison vancomycin and gentamicin, were characterized against both planktonic and biofilm MRSA using the minimum inhibitory concentration (MIC) assay, serial passages, and serial dilution tests against established biofilms grown with a CBR 90 CDC biofilm reactor. Despite a similar MIC (1 µg/ml) and behavior in a 25-day serial passage analysis, CZ-01127 displayed much greater bactericidal activity against established biofilms and was the only to decrease biofilm colony forming units (CFUs) below detectable limits at the highest concentration tested (500 µg/ml). Coating release profiles were characterized using ATR-FTIR and displayed burst release kinetics within the decisive period of the perioperative window suggesting the silicon carrier is broadly useful for screening antibiotic compound for local delivery applications. STATEMENT OF SIGNIFICANCE: With an aging population, an increasing number of people are undergoing total joint replacement procedures in which diseased joint tissues are replaced with permanent metallic implants. Some of these procedures are burdened by costly and debilitating infections. A promising approach to prevent infections is the use of an antimicrobial coating on the surface of the implant which releases antibiotics into the surgical site to prevent infection. In this study, we tested a new antibiotic compound formulated in a silicone coating. Data showed that this compound was more effective at killing pathogenic methicillin resistant Staphylococcus aureus (MRSA) bacteria than two clinical gold-standard antibiotics-vancomycin and gentamicin-and could be a promising agent for antimicrobial coating technologies.

Synthesis of steroidal 1,2- and 1,3-diamines as ligands for transition metal ion complexation

Two series of cholestane-based diamines (1,2 and 1,3) were synthesized using simple and efficient procedures. The convenient substrates for these syntheses were cholesteryl mesylate and tosylate, which were converted to appropriate amines via easily obtained azides. The final diamines were prepared using a substitution reaction with bromoacetonitrile (in the case of 1,2-diamines) or condensation with acrylonitrile (in the case of 1,3-diamines), followed by the reduction of intermediate aminonitriles. Furthermore, the other two amines were synthesized from 16-dehydropregnenolone acetate using aza-Michael addition as a key step. Some of the diamines were subjected to complexation reactions with K₂PtCl₄ to form steroidal analogs of cisplatin. The synthetic methods tested in this work will allow us to prepare other cisplatin derivatives based on steroids showing anticancer properties themselves.

Chemistries for Making Additive Nanolithography in OrmoComp Permissive for Cell Adhesion and Growth

Two-photon lithography allows writing of arbitrary nanoarchitectures in photopolymers. This design flexibility opens almost limitless possibilities for biological studies, but the acrylate-based polymers frequently used do not allow for adhesion and growth of some types of cells. Indeed, we found that lithographically defined structures made from OrmoComp do not support E18 murine cortical neurons. We reacted OrmoComp structures with several diamines, thereby rendering the surfaces directly permissive for neuron attachment and growth by presenting a surface coating similar to the traditional cell biology coating achieved with poly-d-lysine (PDL) and laminin. However, in contrast to PDL-laminin coatings that cover the entire surface, the amine-terminated OrmoComp structures are orthogonally modified in deference to the surrounding glass or plastic substrate, adding yet another design element for advanced biological studies.

Ultrasonic synthesis of Oct. trans-Br2Cu(N ∩ N)2 Jahn-Teller distortion complex: XRD-properties, solvatochromism, thermal, kinetic and DNA-binding evaluations

Under mode of ultrasonic vibration, the neutral octahedral mononuclear [trans-CuBr₂(N ∩ N)₂]·3H₂O complex with N ∩ N = 2,2-dimethylpropane-1,3-diamine was obtained. The structure of the desired complex was characterized by UV-Vis. spectroscopy, FT-IR, EDX, MS, SEM, TG/DTA and CHN-analysis. The octahedral-structure of the desired Cu(II) complex was proven via XRD single-crystal diffraction and its molecular interactions were computed by Hirschfeld surface analysis. Alcohol (as solvent) and short ultrasonic vibration dose period played a critical role in sonochemistry synthesis of octahedral neutral trans-CuBr₂(N ∩ N)₂ complex instead of trigonal bi-pyramidal monocation [CuBr(N ∩ N)₂]Br one. Due to the Jahn-Teller effect, the complex exhibited a trans bonds elongation along Br-Cu-Br axis originating a distorted-octahedral Cu(II), as revealed by the XRD measurements (Br-Cu = 3.04 Å). Therefore, the Solvatochromic behavior of the complex was successfully performed since the trans di-bromide ions are loosely coordinated to Cu(II) center, the change in complex solutions colors by using different solvents which can be detected even by naked-eye supported atypical Jahn-Teller elongation effect formation. TG/DTA and Flynn Wall Ozawa (FWO) isoconversional kinetic methods were applied for the complex to figure out the thermal behavior, kinetic of the ligands de-structured and estimate its Ea/α relation. The complex binding mode to the CT-DNA was examined by UV-vis. spectroscopic, melting curve, CV and viscosity tests. The complex exhibited very strong DNA binding via an intercalation mode of coordination with K_b = 6.5 × 10⁵ value.

Ultrasound-assisted synthesis of two novel [CuBr(diamine)2·H2O]Br complexes: Solvatochromism, crystal structure, physicochemical, Hirshfeld surface thermal, DNA/binding, antitumor and antibacterial activities

Two new hydrated monocationic Cu(II) complexes with 1,3-propylenediamine and 1,2-ethylenediamine of general formula [CuBr(N-N)₂·H₂O]Br were prepared. The complexes were identified by means of several spectroscopic tools (Uv-visible, IR and MS), thermally (TG/DTA) and CHN-elemental analysis. The three dimensional structure for complex A and B was provide by X-ray diffraction studies and showed the Cu(II) ion as 4 + 1 + 1 coordinated, four nitrogen atoms of the diamine ligands, one bromide ion and one H₂O semi-coordinated to the Cu(II) center, a typical trans effect is clearly observed in the two complexes. The molecular crystal structures are linked via several H-bonds like N_H…Br and N_H…O. Additionally, intra-molecular H-bonds of kind C_H…Br is observed; these interactions lead to crystal structure three dimensional architecture packing. Hirshfeld surfaces (HSA) analysis was served to figure out the inter-contacts and fingerprints atoms percentage. DNA-binding, antitumor and antibacterial effectiveness of the desired complexes were evaluated.

Synthesis, Characterization, and Antimicrobial Properties of Peptides Mimicking Copolymers of Maleic Anhydride and 4-Methyl-1-pentene

Synthetic amphiphilic copolymers with strong antimicrobial properties mimicking natural antimicrobial peptides were obtained via synthesis of an alternating copolymer of maleic anhydride and 4-methyl-1-pentene. The obtained copolymer was modified by grafting with 3-(dimethylamino)-1-propylamine (DMAPA) and imidized in a one-pot synthesis. The obtained copolymer was modified further to yield polycationic copolymers by means of quaternization with methyl iodide and dodecyl iodide, as well as by being sequentially quaternized with both of them. The antimicrobial properties of obtained copolymers were tested against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis, and Staphylococcus aureus. Both tested quaternized copolymers were more active against the Gram-negative E. coli than against the Gram-positive S. aureus. The copolymer modified with both iodides was best when tested against E. coli and, comparing all three copolymers, also exhibited the best effect against S. aureus. Moreover, it shows (limited) selectivity to differentiate between mammalian cells and bacterial cell walls. Comparing the minimum inhibitory concentration (MIC) of Nisin against the Gram-positive bacteria on the molar basis instead on the weight basis, the difference between the effect of Nisin and the copolymer is significantly lower.

Discovery of antitumor ursolic acid long-chain diamine derivatives as potent inhibitors of NF-κB

A series of inhibitors of NF-κB based on ursolic acid (UA) derivatives containing long-chain diamine moieties were designed and synthesized as well as evaluated the antitumor effects. These compounds exhibited significant inhibitory activity to the NF-κB with IC50 values at micromolar concentrations in A549 lung cancer cell line. Among them, compound 8c exerted potent activity against the test tumor cell lines including multidrug resistant human cancer lines, with the IC50 values ranged from 5.22 to 8.95 μM. Moreover, compound 8c successfully suppressed the migration of A549 cells. Related mechanism study indicated compound 8c caused cell cycle arrest at G1 phase and triggered apoptosis in A549 cells through blockage of NF-κB signalling pathway. Molecular docking study revealed that key interactions between 8c and the active site of NF-κB in which the bulky and strongly electrophilic group of long-chain diamine moieties were important for improving activity.