9-anthracene Carboxylic Acid Research Articles

Secretion of citrate from roots in response to aluminum and low phosphorus stresses in Stylosanthes

Excess aluminum (Al) ions and phosphorus (P) deficiency are the key factors that limit plant growth in acid soils. Secretion of organic acids (OA) from roots has been proposed as an Al-resistance mechanism. Nonetheless, the correlation between Al resistance and this mechanism has not been tested beyond a very small number of Al-resistant and Al-sensitive genotypes. To elucidate the mechanisms responsible for plant adaptability to acid soils, we studied the secretion of OA from roots of Stylosanthes in response to high-Al and low-P stresses using six different genotypes. Relative root inhibition by 50 µM Al ranged from 25–71% and differed significantly among six Stylosanthes genotypes. Al treatment induced the secretion of citrate from the roots of Stylosanthes seedling in a dose- and time-dependent manner. Moreover, the secretion rate was significantly higher in the Al-resistant genotype. On the other hand, inhibition of Al-induced citrate secretion by phenylisothiocyanate or 9-anthracenecarboxylic acid resulted in an increase in Al content in Stylosanthes root apices. P deficiency also induced citrate secretion from Stylosanthes seedling roots. Furthermore, citrate secretion was much more robust with exposure to both excess-Al and P-deficiency stresses than under either stress alone. Unlike Al-induced citrate secretion, which was rapid, low-P-induced secretion was a slow process, with significant increases in secretion only becoming evident after 6 d of treatment with free phosphate. The lag between treatment with Al and citrate secretion was approximately 4 h. These results suggest that the secretion of citrate is a mechanism for resistance to both excess-Al and low-P stresses in Stylosanthes.

DHPR Activation Is A Prerequisite For SR Ca2+ Release Induced By Increased Osmolarity In Isolated Rat Skeletal Muscle Fibres

Rat flexor digitorum brevis (FDB) fibres were superfused with isoosmotic Tyrode's solution before exposure to either hyperosmotic (405 mOsm) or hypoosmotic (254 mOsm) solutions, and the effects on cell volume, membrane potential (Em) and intracellular Ca2+ ([Ca2+]i) determined. Solutions were made hyperosmotic by addition of sugars or divalent cations, and hypoosmotic by reducing [NaCl]o. Under control conditions, FDB fibres typically exhibited a low resting Em of -60.1 ± 2.91, n=67. All hyperosmotic solutions induced a sustained decrease in cell volume, membrane depolarisation (by ∼14-18 mV, n=40) and SR Ca2+ release. However, sugar solutions caused a pronounced increase in global [Ca2+]i, while solutions made hyperosmotic by addition of divalent cations induced only LCR. Decreasing osmolarity caused an increase in cell volume and membrane hyperpolarisation (15.04 ± 1.85 mV, n=8), while [Ca2+]I was unaffected. However, on return to the isoosmotic solution, restoration of cell volume and Em was accompanied by LCR. With all protocols, SR Ca2+ release was markedly inhibited by the RyR1 inhibitor tetracaine or the dihydropyridine receptor (DHPR) inhibitor nifedipine. Inhibition of sarcolemmal Cl− channels with 9-anthracene carboxylic acid (9-AC) or the Na/K/2Cl (NKCC) co-transporter with furosemide, both induced a marked hyperpolarisation of Em to -79.2 ± 3.7 mV (n=8) and -89.2 ± 1.7 mV (n=17), respectively. In the presence of furosemide, the depolarisation associated with hyperosmotic shrinkage was reduced by 48.3 ± 2.3 % (n=7). These findings suggest that (i) tonic activation of the NKCC co-transporter and consequent effects on [Cl]i underlie the low resting Em in FDB fibres and (ii) the initiation of LCR that accompanies a decrease in cell is caused by membrane depolarisation, which may be linked to increased activity of the NKCC co-transporter.

Spectroscopic properties of lanthanoid benzene carboxylates in the solid state: Part 1

Europium and terbium complexes of benzoic acid (HBA), 9-anthracene carboxylic acid (9-HACA), 1-naphthoic acid (1-HNA), 2-naphthoic acid (2-HNA), cinnamic acid (HCA), o-phenylbenzoic acid ( o-HPhBA), p-phenylbenzoic acid ( p-HPhBA), o-methylbenzoic acid ( o-HMeBA), m-methylbenzoic acid ( m-HMeBA), p-methylbenzoic acid ( p-HMeBA), p- tert-butylbenzoic acid ( p- tert HBuBA), phthalic acid (H 2Phth), isophthalic acid (H 2-IsoPhth) and terephthalic acid (H 2-TerePhth) were synthesised by aqueous metathesis reactions. The compositions were determined by microanalysis, DTA, and EDTA volumetric methods. Structural conclusions were drawn from powder XRD patterns and IR spectra. The optoelectronic properties were determined in the solid state, including reflectance, excitation, emission, and excitation efficiency, complemented by considering triplet state energies, which were derived from phosphorescence spectra of the corresponding gadolinium complexes. Besides the emission efficiencies, the splitting pattern of the 5D 0 → 7F J transitions of Eu 3+ were used to derive structural information and the intensities relative to the 5D 0 → 7F J were used to gain information about the mechanism, adding electronic allowed dipole character to the forbidden emissions.

Template assisted synthesis of silica-coated molecular crystal nanorods: From hydrophobic to hydrophilic nanorods

We report a method for the preparation of silica-coated molecular crystal nanorods. A sol–gel method was used to make silica nanotubes inside anodized alumina templates. The nanotubes were then loaded with 9-anthracene carboxylic acid (9-AC) and solvent annealed to produce silica-coated organic nanorods. The core–shell structure was confirmed using electron microscopy, and the highly crystalline organic core was characterized using powder X-ray diffraction and transmission electron microscopy. The silica-coated 9-AC rods had much improved dispersal properties in aqueous solution, and were also able to undergo reversible bending under UV illumination, as observed previously for uncoated 9-AC rods. This work demonstrates that it is possible to make surface-coated molecular crystal nanorods that retain their useful functionalities.

Secretion of malate and citrate from roots is related to high Al-resistance in Lespedeza bicolor

Lespedeza bicolor (Lespedeza bicolor Turcz. cv. Jiangxi) is a leguminous shrub that is well adapted to acid infertile soils. However, the mechanisms of aluminum resistance in this species have not been established. This study aimed to assess the possible resistance mechanisms of this plant to Al. An Al-sensitive species of Lespedeza, sericea lespedeza [Lespedeza cuneata (Dum.-Cours.) G. Don cv. Zhejiang], was used as a reference. The roots of L. bicolor secreted both malate and citrate after exposure to Al, but roots of L. cuneata did not. The secretion of organic acids from L. bicolor was specific to Al; neither 15-day P starvation nor 50 μM lanthanum induced the secretion of these organic acid anions. Secretion of organic acid anions in L. bicolor was detected after 3–6 h exposure to Al, and the amount increased significantly after 6 h exposure, suggesting that this plant shows a pattern II-type organic acid secretion. This is supported by the finding that the secretion was significantly inhibited by a protein-synthesis inhibitor, cycloheximide. Two kinds of anion-channel inhibitors had different effects on Al-induced secretion of organic acids: 9-anthracene carboxylic acid completely inhibited secretion, phenylglyoxal had no effect. Root elongation in L. bicolor was more severely inhibited by Al in the presence of 9-anthracene carboxylic acid. All these results indicated that the secretion of malate and citrate is a specialized response to Al stress in L. bicolor roots, which might be one of the Al-resistance mechanisms in this species.

Chloride conductance in the transverse tubular system of rat skeletal muscle fibres: importance in excitation–contraction coupling and fatigue

Contraction in skeletal muscle fibres is governed by excitation of the transverse-tubular (t-) system, but the properties of the t-system and their importance in normal excitability are not well defined. Here we investigate the properties of the t-system chloride conductance using rat skinned muscle fibres in which the sarcolemma has been mechanically removed but the normal excitation-contraction coupling mechanism kept functional. When the t-system chloride conductance was eliminated, either by removal of all Cl(-) or by block of the chloride channels with 9-anthracene carboxylic acid (9-AC) or by treating muscles with phorbol 12,13-dibutyrate, there was a marked reduction in the threshold electric field intensity required to elicit a t-system action potential (AP) and twitch response. Calculations of the t-system chloride conductance indicated that it constitutes a large proportion of the total chloride conductance observed in intact fibres. Blocking the chloride conductance increased the size of the twitch response and was indicative that Cl(-) normally carries part of the repolarizing current across the t-system membrane on each AP. Block of the t-system chloride conductance also reduced tetanic force responses at higher frequency stimulation (100 Hz) and greatly reduced twitch responses in the period shortly after a brief tetanus, owing to rapid loss of t-system excitability during the AP train. Blocking activity of the Na(+)-K(+) pump in the t-system membrane caused loss of excitability owing to K(+) build-up in the sealed t-system, and this occurred approximately 3-4 times faster when the chloride conductance was blocked. These findings show that the t-system chloride conductance plays a vital role during normal activity by countering the effects of K(+) accumulation in the t-system and maintaining muscle excitability.

Utilization of Nanometre-order Diameter Columns inside Porous Anodic Alumina for Chromatography Chip System

Abstract Porous anodic alumina (PAA) membranes were used as a nanometre-order diameter column for chromatography chip with acetonitrile–water mobile phase using gradient elution. In a chromatogram, 9-anthracenemethanol (AM), 9-anthracenecarboxylic acid (AC), and dansyl–glycine (DG) showed different retention times, indicating that PAA membranes are applicable to stationary phase for chromatography chip.

Photopolymerization of Organic Molecular Crystal Nanorods

The dianthracene molecule 9-anthracenecarboxylic acid, methylene ester (9AC-ME) was synthesized and used to form molecular crystal nanorods using anodized aluminum oxide templates. A high-temperature solvent annealing process generated a crystal polymorph where neighboring monomers had overlapping anthracene moieties. Subsequent exposure to ultraviolet light caused the monomers to undergo a [4 + 4] photocycloaddition reaction, forming highly crystalline polymer nanorods of poly(9AC-ME). The polymer nanorods are flexible, resistant to breakage, and insoluble in organic solvents and strong acid/base solutions. Their molecular structure is characterized by powder X-ray diffraction, solid-state NMR, and UV−vis spectroscopy. Different diameter crystalline polymer nanorods could be fabricated using alumina templates of variable pore diameter.

Heavy atom effects on anthracene-rigid-rod excited states anchored to metal oxide nanoparticles

Two new organic rigid-rod linker compounds, dimethyl 5-(1-anthracenylethynyl)isophthalate and dimethyl 5-(4-(1-anthracenynyl)phenylethynyl)-isophthalate, were used to couple anthracene to the surface of TiO 2 (anatase) and ZrO 2 nanoparticle thin films. These anthracene-rigid-rod molecules have high extinction coefficients and absorbance spectra that are red-shifted relative to 9-anthracenecarboxylic acid (9-AC). The rigid-rod linkers afford high surface coverages, ∼10 −8 mol/cm 2, on the nanostructured films in acetonitrile. Excimer-like emission on ZrO 2 nanoparticles suggests that the rigid-rods do not spatially isolate the anthracene chromophores effectively. On TiO 2 fluorescence was observed for both anthracene-rigid-rods while it was not detected for 9-AC consistent with quantitative electron injection into the semiconductor. Organoiodides and thallium cations (Tl +) were found to be heavy atom quenchers of the anthracene fluorescence in acetonitrile with a concentration dependence that followed the Stern–Volmer model. Fluorescence on ZrO 2 was quenched less efficiently by the organoiodides while Tl + cations exhibited enhanced quenching that followed the Stern–Volmer model at low Tl + concentrations and saturated at higher concentrations, behavior attributed to surface adsorption.

Ag 2(aca) 2] n and [Ag 4(aca) 4(NH 3) 2] (acaH = 9-anthracenecarboxylic acid): Synthesis, X-ray crystal structures, antimicrobial and anti-cancer activities

[Ag 2(9-aca) 2] n and [Ag 4(9-aca) 4(NH 3) 2] (9-acaH = 9-anthracenecarboxylic acid) have been prepared and structurally characterized. [Ag 2(9-aca) 2] n consists of polymeric ribbons of linked disilver(I) syn–syn bridged dicarboxylate units. [Ag 4(9-aca) 4(NH 3) 2] is tetrameric and centrosymmetric, with two syn–syn bridging carboxylates linked to the bimetallic Ag–Ag core and a further two syn–anti bridged carboxylate ligands in the equatorial plane, being coordinated to one Ag in the bimetallic core and to a second Ag, with the latter also bonded to an NH 3 ligand. In vitro studies show that both complexes are extremely cytotoxic against selected human fungal and bacterial pathogens, and each complex also greatly inhibits the growth of two mammalian cancer cell lines.

Synthesis, characterization, and molecular structures of di- and triorganotin(IV) complexes with 9-anthracenecarboxylic acid: The structural diversity in organotin 9-anthracenecarboxylates

The di- and triorganotin(IV) derivatives of anthracenecarboxylic acid, Ph 2MeSnOC(O)C 14H 9 ( 2), Me 3SnOC(O)C 14H 9 ( 3), Me 2Sn[OC(O)C 14H 9] 2 · CH 3OH ( 4) Ph 3SnOC(O)C 14H 9 · CH 3OH ( 5), Ph 2EtSnOC(O)C 14H 9 ( 6), Ph 2Sn[OC(O)(C 14H 9)] 2 ( 7) and PhMe 2SnOC(O)C 14H 9 ( 8) were synthesized by the reaction of Ph 2MeSnI, Me 3SnCl, Me 2SnCl 2, Ph 3SnCl, Ph 2EtSnI, Ph 2SnCl 2, and PhMe 2SnI with 9-anthracenecarboxylic acid, respectively, with the aid of potassium iso-propoxide. All complexes were characterized by elemental analysis, mass spectrometry, IR, 1H, 13C and 119Sn NMR spectroscopes. The molecular structures of complexes 2, 3 and 4 were determined by single crystal X-ray analysis. The X-ray structures reveal that complex 2 and 3 adopt a polymeric trans-C 3SnO 2 trigonal bipyamidal configuration with the oxygen atoms occupying axial positions. Complex 4 adopts a monomeric structure with two carboxylates coordinated to tin in a monodentate form from axial and equatorial positions, and with the coordination number raised to five as the methanol occupies the apical position of the trigonal bipyramid.

Reversible Photoinduced Shape Changes of Crystalline Organic Nanorods

Crystalline nanorods composed of 9-anthracene carboxylic acid (9-AC) are synthesized using nanoporous Al2O3 templates. When a segment of an isolated rod is exposed to UV-light, localized solid-state photodimerization of the 9-AC molecules induces micrometer-scale bending (see figure). The nanorod reverts back to its original shape after several minutes in the dark at room temperature. The reversible photoinduced shape change could be repeated multiple times.

Vapor pressures and thermodynamics of oxygen-containing polycyclic aromatic hydrocarbons measured using Knudsen effusion.

Polycyclic aromatic hydrocarbons (PAHs) and their oxygenated derivatives (OPAHs) are ubiquitous environmental pollutants resulting from the incomplete combustion of coal and fossil fuels. Their vapor pressures are key thermodynamic data essential for modeling fate and transport within the environment. The present study involved nine PAHs containing oxygen heteroatoms, including aldehyde, carboxyl, and nitro groups, specifically 2-nitrofluorene, 9-fluorenecarboxylic acid, 2-fluorenecarboxaldehyde, 2-anthracenecarboxylic acid, 9-anthracenecarboxylic acid, 9-anthraldehyde, 1-nitropyrene, 1-pyrenecarboxaldehyde, and 1-bromo-2-naphthoic acid. The vapor pressures of these compounds, with molecular weights ranging from 194 to 251 g/mol, were measured using the isothermal Knudsen effusion technique in the temperature range of 329 to 421 K. The corresponding enthalpies of sublimation, calculated via the Clausius-Clapeyron equation, are compared to parent, nonoxygenated PAH compound data to determine the effect of the addition of these oxygen-containing heteroatoms. As expected, the addition of -CHO, -COOH, and -NO(2) groups onto these PAHs increases the enthalpy of sublimation and decreases the vapor pressure as compared to the parent PAH; the position of substitution also plays a significant role in determining the vapor pressure of these OPAHs.

Antiferromagnetic tetranuclear manganese complex: Wheel or dicubane?

[Mn 4(anca) 4(Htea) 2(dbm) 2] · 2.5Et 2O ( 1) (dbm − is the mono-anion of dibenzoylmethane, anca − is the anion of 9-anthracenecarboxylic acid and Htea is the dianion of triethanolamine) has been characterized through X-ray crystallographic and magnetic susceptibility techniques. Complex 1 is comprised of an alkoxy-bridged [ Mn 2 III Mn 2 II O 4 ] wheel-shaped core with an across-wheel Mn II⋯O distance of ∼2.7 Å. Variable-temperature dc magnetic susceptibility data were collected between 300 K and 1.8 K with an applied dc field of 0.1 T. Complex 1 exhibits a gradual decrease in magnetic susceptibility with decreasing temperature which is indicative of antiferromagnetic exchange interactions. Least squares fitting employing the Kambe approach with one J-value yielded an S = 1 ground state and fitting parameters of g = 1.8 and J = −2.1 cm −1. A fit with the Kambe approach assuming two different J-values, where one represents an across-wheel Mn II⋯Mn II interaction, did not improve on the fit. Analysis was also carried out on the variable temperature dc susceptibility and magnetization versus field data (5, 4, 3, 2 and 1 T in the 1.8–4.0 K range) using a full matrix diagonalization approach Preliminary calculations have yielded fitting parameters of g = 2.2, J = −2.8 cm −1 and D = −9.2 cm −1. In this case the 900 × 900 matrix included terms for the single-ion zero-field interactions, HDVV and antisymmetric exchange interactions as well as Zeeman interactions for the [ Mn 2 III Mn 2 II ] complex.

Ionic involvement and kinase activity on the mechanism of nongenomic action of thyroid hormones on 45Ca 2+ uptake in cerebral cortex from young rats

Thyroid hormones (TH) play important roles in brain development. Although most of the nongenomic actions of TH are known to be calcium-dependent, the effects of 3,5,3′-triiodo- l-thyronine (T 3) or thyroxine (T 4) on calcium influx in cerebral cortex of rats are not clear. In this study we investigate some mechanisms involved in the effect of T 3 and T 4 on Ca 2+ uptake in slices of cerebral cortex from 10-day-old male rats. Results indicated 10 −6 M T 3 or 10 −7 M T 4 was able to increase 45Ca 2+ uptake after 30 s of hormone exposure. The involvement of L- and T-type voltage-dependent Ca 2+ channels (VDCC) on the effect of TH on 45Ca 2+ uptake was evidenced by using nifedipine and flunarizine, L- and T-type channel blockers, respectively. Otherwise, chloride currents were not involved in the hormone actions, as demonstrated by using 9-anthracene carboxylic acid, a Cl −-channel blocker. In addition, results demonstrated a PKC-dependent mechanism for both T 3 and T 4, as evidenced by stearoylcarnitine chloride, a specific PKC inhibitor. Furthermore, we verified that the T 3 action was also mediated by PKA activity, as demonstrated coincubating T 3 and KT 5720 (PKA inhibitor), and reinforced by using theophylline, a phosphodiesterase inhibitor. In contrast, concerning the effect of T 4, results suggest a partial involvement of PKA activity, and demonstrated that high cAMP levels were not able to support the effect of T 4, suggesting the participation of G inhibitory protein-coupled receptor in the action of this hormone on 45Ca 2+ uptake. In conclusion, our results evidence a nongenomic action of TH promoting Ca 2+ influx by ionic channels involving mechanisms dependent on kinase activities. It is possible that the modulation of Ca 2+ channels by kinase activities represent an important membrane action of TH signaling mechanism in the central nervous system during development.

Electron-Transfer Reagent Anion Formation via Electrospray Ionization and Collision-Induced Dissociation

A strategy is described and demonstrated for the formation of reagent anions via electrospray ionization (ESI) for electron-transfer dissociation (ETD). To circumvent difficulties associated with formation of high mass-to-charge ratio (m/z) reagent anions, it is desirable to form ETD reagents via means other than those that require reagent molecule vaporization. ESI is a candidate method, but anions that are generally generated efficiently by ESI tend to react with multiply protonated polypeptides via proton transfer. The strategy described herein involves the use of a precursor reagent molecule that ionizes efficiently via electrospray ionization and that can subsequently be converted to an ETD reagent via gas-phase dissociation. The approach is demonstrated with arenecarboxylic acids that yield strong signals associated with the deprotonated molecule and that subsequently undergo collision-induced dissociation (CID) by loss of CO(2). In the present work, triply protonated KGAILKGAILR served as a test substrate for the CID product ions to give rise to ETD. Several precursor molecules were shown to be capable of generating ETD reagents via ESI followed by CID. These included 9-anthracenecarboxylic acid, 2-fluoro-5-iodobenzoic acid, and 2-(fluoranthene-8-carbonyl)benzoic acid. The latter molecule has the most attractive set of characteristics as a precursor for a relatively high m/z ratio ETD reagent.

Characterization of a novel voltage-dependent outwardly rectifying anion current in Caenorhabditis elegans oocytes

An inwardly rectifying swelling- and meiotic cell cycle-regulated anion current carried by the ClC channel splice variant CLH-3b dominates the whole cell conductance of the Caenorhabditis elegans oocyte. Oocytes also express a novel outwardly rectifying anion current termed I(Cl,OR). We recently identified a worm strain carrying a null allele of the clh-3 gene and utilized oocytes from these animals to characterize I(Cl,OR) biophysical properties. The I(Cl,OR) channel is strongly voltage dependent. Outward rectification is due to voltage-dependent current activation at depolarized voltages and rapid inactivation at voltages more hyperpolarized than approximately +20 mV. Apparent channel open probability is zero at voltages less than +20 mV. The channel has a 4:1 selectivity for Cl(-) over Na(+) and an anion selectivity sequence of SCN(-) > I(-) > Br(-) > Cl(-) > F(-). I(Cl,OR) is relatively insensitive to most conventional anion channel inhibitors including DIDS, 4,4'-dinitrostilbene-2,2'-disulfonic acid, 9-anthracenecarboxylic acid, and 5-nitro-2-(3-phenylpropylamino)benzoic acid. However, the current is rapidly inhibited by niflumic acid, metal cations including Gd(3+), Cd(2+), and Zn(2+), and bath acidification. The combined biophysical properties of I(Cl,OR) are distinct from those of other anion currents that have been described. During oocyte meiotic maturation, I(Cl,OR) activity is rapidly downregulated, suggesting that the channel may play a role in oocyte Cl(-) homeostasis, development, cell cycle control, and/or ovulation.

Vacuum Ultraviolet Postionization of Aromatic Groups Covalently Bound to Peptides

Experiments demonstrate that peptides with ionization potentials (IPs) above 7.87 eV can be single-photon-ionized in the gas phase with a molecular fluorine laser following prior chemical derivatization with one of several aromatic tags acting as chromophores. 4-(Dimethylamino)benzoic acid, 1-naphthylacetic acid, and 9-anthracenecarboxylic acid (denoted Benz, Naph and Anth, respectively) behave as chromophores, allowing single-photon ionization for vacuum ultraviolet (VUV) laser light by lowering the IP of the tagged peptide. Anth-tagged peptides that are laser-desorbed from a substrate and subsequently postionized produce mass spectra dominated by the intact radical cation, although protonated ions and fragmented species are also observed. Electronic structure calculations on Anth-tagged peptides indicate that in addition to lowering the ionization potential, the presence of the aromatic tag increases charge localization on and delocalization across the ring structure, which presumably stabilizes the radical cation. Measurements on several tagged peptides confirm this calculation and show that the stabilizing effect of the tag increases with the size of the conjugated system in the order Benz < Naph < Anth. The tagged hexapeptide Anth-GAPKSC exhibits the parent ion, whereas the Benz- and Naph-tagged peptides do not. These results are supported by the experimental comparison of Anth-tagged vs untagged tryptophan, further suggesting that VUV postionization of tagged high-IP species is a promising method for expanding the capabilities of mass spectrometric analyses of molecular species.

Induction of cytochrome P450 by Nrf2 activators: Implication for aldehyde metabolism

Acrolein is an environmental pollutant and product of lipid peroxidation in vivo. Acrolein mediates the activation of Nrf2, so we sought to determine whether Nrf2 regulates clearance of acrolein by inducing specific hepatic P450s. The routes of metabolism of acrolein and α,β-unsaturated aldehydes include carboxylic acid and alcohol formation. C57BL/6 mice were fed either 5 mg/kg of acrolein by gavage for 72 h or AIN76 diet containing 0.45 % BHA, a Nrf2 activator, for 7 days. Mouse liver was frozen at −80 ° and after extraction, the RNA was reverse transcribed to cDNA. Cyp2c29 mRNA levels were analyzed by QRT-PCR. Liver microsomal protein fractions were prepared from control or BHA-fed mouse liver. Our results indicate that hepatic Cyp2c29 mRNA levels were induced 5-fold in BHA-treated mice and 2-fold in acrolein-treated mice. Likewise, there was a two-fold higher activity for 9-anthracene aldehyde oxidation to 9-anthracene carboxylic acid and reduction to 9-anthracene methanol with BHA-treated mouse liver microsomes, reactions catalyzed by Cyp2c29 expressed in E. coli. These reactions were inhibited 90% by 0.5 mM miconazole, a general P450 inhibitor, but only slightly inhibited by troleandomycin, a Cyp3a11-specific inhibitor or cyanamide, an aldehyde dehydrogenase inhibitor. Cyp3A11 mRNA levels remained unchanged upon BHA feeding. This suggests that the aldehyde oxidation and reduction activity present in murine hepatic microsomes is predominantly mediated by Cyp2c29. Supported by USPHS P01 ES11860.

Synthesis of novel gem-difluorinatedcyclopropane hybrids: Applications for DNA cleavage agents switched by photo irradiation

A strong DNA cleavage property switched by photo irradiation was found for 9-anthracenecarboxylic acid substituted gem-difluorocyclopropane derivatives; in particular, a clear contrast in the activity was observed between the enantiomers of ( S, S)- and ( R, R)-3-aminomethyl-2,2-difluorocyclopropylmethyl 9-anthracenecarboxylate.