In this paper we present the inhibitory effect of a variety of structurally modulated/modified polyphenolic compounds on purified F1 or membrane bound F1FoEscherichia coli ATP synthase. Structural modulation of polyphenols with two phenolic rings inhibited ATP synthase essentially completely; one or three ringed polyphenols individually or fused together inhibited partially. We found that the position of hydroxyl and nitro groups plays critical role in the degree of binding and inhibition of ATPase activity. The extended ...

We examined the thymoquinone induced inhibition of purified F 1 or membrane bound F 1 F O E. coli ATP synthase. Both purified F 1 and membrane bound F 1 F O were completely inhibited by thymoquinone with no residual ATPase activity. The process of inhibition was fully reversible and identical in both membrane bound F 1 F o and purified F 1 preparations. Moreover, thymoquinone induced inhibition of ATP synthase expressing wild-type E. coli cell growth and non-inhibition of ATPase gene deleted null control cells demonstrates that ATP synthase is a molecular target for thymoquinone. This also links the beneficial dietary based antimicrobial and anticancer effects of thymoquinone to its inhibitory action on ATP synthase.

2,6-Dicarboxypyridine (DCP) and N,N-bis(2-picoly1)amine (DPA) ligands were synthesized and attached via ethylene groups to the 5'-ends of 12-base oligonucleotides. The base-sequence of the oligonucleotide probes were chosen to be 5'-T-C-G-CC -T-T-G-C-A-G-C-3', which is complementary to a 12-base sequence in pUC9 plasmid DNA. When hybridized to a denatured BamHI/PvuI restriction fragment of pUC9 in the presence of Fe2+, oxygen, and a reducing agent, these probes afforded specific cleavage at their complementary sequences in the 135-base-pair template. Analysis of the cleavage fragments by high-resolution polyacrylamide gel electrophoresis indicated that both probes cleaved DNA at a single stretch of bases near the position of the tethered ligand. The cleaving activity of DPA-12-mer was unusually high and extended over eight contiguous nucleotides. DCP-12-mer showed an unprecedented high cleavage specificity extending over two nucleotides only.

تم استخدام مخمر صناعي سعة 2 لتر لاختيار مقدرة الفطرة على تكوين هذه المادة في ظروف تشبه تلك المطبقة في الصناعة . وبدراسة تركيزات متعددة فن مادة البروجستيرون تتراوح ما بين 10جرام /لتر إلى 50جرام /لتر ، وجد أن أنسب التركيزات المختبرة هو تركيز 20 جرام من البروجستيرون لكل لترمن الوسط الغذائي ، حيث تم تحويل كل البووجستيرون المضاف إلى المشتقات المختلفة خلال 72 ساعة من بدء الاضافة . ووجد أن أعلى معدل لتكوين مادة 17 ألفا - هيدروكسي البروجستيرون كان بعد 48 ساعة من بدأ إضافة البروجستيرون . عند فصل المواد الناتجة من تحول البروجستيرون بواسطة الفطرة المستخدمة وذلك بواسطة أعمدة الفصل باستخدام مادة الالومينا وجد أن البروجستيرون يتحول إلى : 17 ألفا - هيدروكسي البروجستيرون ( 54 %) 11 ألفا - هيدروكسي البروجستيرون (29%) 11 ألفا ، 17 ألفا - ثنائي هيدروكسي البروجستيرون (2.5%)

A series of structurally related diphenol aldimines (DPAs) were synthesized. These aldimines involve different substitution patterns of their phenolic groups, for the purpose of optimizing their ability to inhibit ATP synthase. The inhibitory effects of these DPA compounds were evaluated using purified F 1 and membrane-bound F 1 F 0 E. coli ATP synthase. Structure-activity relationship studies of these diphenol compounds showed that maximum inhibition was achieved when both phenolic groups are either in the meta-positions (DPA-7, IC 50 = 2.0 μM), or in the ortho-positions (DPA-9, IC 50 = 5.0 μM). The lowest ATP synthase inhibition was found to be when the phenolic groups are both in the para-positions (DPA-2, IC 50 = 100.0 μM). Results also show that the inhibitory effects of these compounds on ATPase are completely reversible. Identical inhibition patterns of both the purified F1 and the membrane bound F 1 F 0 enzyme were observed. Study of E. coli cell growth showed that these diphenol aldimines effectively inhibit both ATP synthesis and cell growth.

Two 12-base oligonucleotides were synthesized and mod&d by attaching metal-binding ligands (2,6-p~~m~ic~boxylate and 2,~-~pi~lyl~ne) to their Sends . When hybridized to a 135base singb stranded DNA, in the presence of Fe a+, q2, and a reducing agent, these oligonucleotides cleaved the complementary DNA chain with unique and high base-sequence specificities. Sequence-specific cleavage of DNA by synthetic probes has been the subject of intensive studies for mom than a decade.14 Sequence-sp~i~~ty in the cleavage of single stranded RNA can be achieved by attaching DNA cleaving groups (e.g., metal complexes) to oligonucleotide probes that have sequences complementary to that of the target DNA.s-a Although such modified oligonucleotide probes have shown high DNA binding specificities, they cleave DNA at several bases around the tethered metal complex due to intermediicy of diffusible free radicals. In an attempt to design probes that can cleave DNA via nondiffusible intermediates, and as a part of our investigadon of the effect of structural variations of the metal complexes on the specificity of DNA cleavage, we report here the synthesis of two modified oligonucleotides Q and 5) and the study of their activities towatd DNA cleavage. The iton complex of? showed an unusually high DNA cleaving activity over a range of proximate bases while that of 1 showed a remarkably high site selectivity. The synthesis of 1 was achieved via compound 2 which was prepared from dimethyl 4-hydroxy-2,6-py~din~ic~~xylate upon reaction with te~y~p~nyl (TIP) derivative of 2-b~rn~~~o1, foliowed by deprotection (Scheme 1). Compotmd 2 was synthesized frvtn 4, which was obtained by reductive amination of 2-pyridinecarboxaldehyde with 2-aminoethanol in the presence of sodium cyanobo~hy~de. The phosphoramidite derivatives (1 and 6) were obtained upon reacting 2 and 4 with methyl N,Ndiisopropylchlorophosphoramidite, respectively. The analytical data for all compounds are consistent with the assigned structures9 1367

ZnCl 2 supported on silica gel has shown to be an effective catalyst for transesterification of the organophosphate insecticide, paraoxon, in the presence of 2-phenylethanol. The kinetics of the reaction in acetonitrile was studied. Formation of the product diethyl 2-phenylethyl phosphate was confirmed by 31 P NMR.

In this paper, a nanometer-sized gold electrode with an effective radius around several tens of nanometers has been modified with a monolayer of alkanethiols. There are pinholes in the monolayer, and the pinholes can be used as very small electrode. Our evaluation shows that it is possible to have only one pinhole on the monolayer covered electrode. The single pinhole electrode has been used to study the electrochemical behaviors of fast and slow electrochemical reactions. Our results show that the electrochemical response of a slow electrochemical reaction is not a Butler-Volmer response if the electrode is small enough.

Simple and novel nuclease models have been synthesized. These involve metal-binding ligand 1,4,7,10tetraazlcyclododecane (cyclen) tethered to an acridine ring (a DNA-binding group) by amide linkers of various lengths. Binding of these probes to DNA was studied by monitoring changes in their UV-visible spectra affected by the presence of DNA. Titration of these compounds with increasing amounts of pBR322 DNA caused hypochromic effects and shifted the acridine absorption at 360 nm to a longer wavelength. Under biologically relevant conditions (37°C and pH 7.4), specific transition metal complexes of these compounds are found to be highly effective catalysts toward the hydrolysis of plasmid DNA. This is demonstrated by their ability to convert the super-coiled DNA (form I) to open-circular DNA (form II). Structure-activity correlation studies show that hydrolytic activity depends on both the structure of ligand (L 1 N L 2 N L 3) and the nature of metal ion cofactor (Co 3+ N Zn 2+ N Cr 2+ N Ni 2+ N Cu 2+ N Fe 3+).

A new method to form a single gold nanoparticle (Au NP) is been introduced. In our method, a single Au NP is spontaneously formed on the surface of a nanometer-sized platinum (Pt) electrode under open circuit potential. The single NP has been characterized by using Scanning Electron Microscopy and electrochemical methods. Electrochemical studies reveal that the small Au particle has extraordinary stability compared to that of a bulk Au phase. The extra stability of the Au NP is attributed to the formation of alloy with the Pt substrate.

A polyamine-zinc(ii) complex with an alcohol pendant promotes the hydrolysis of diethyl(4-nitropheny1)phosphate via transfer of the diethylphosphate group to its alkoxy pendant. In recent years there has been considerable interest in the metal ion-promoted hydrolysis of phosphate esters as model systems for phosphatase enzymes. 1-6 Most of the enzymes responsible for the metabolism of phosphate compounds require divalent metal ions such as Zn2+, Mg2+ or Mn2+ for activation.7 For instance, alkaline phosphatase is known to contain at least one ZnII ion at the active site during the catalytic cycle of the enzyme.* It is believed that the substrate is initially attacked by the deprotonated serine at the active site to yield a transient phosphoseryl intermediate, which is then attacked by the adjacent ZnII-bound hydroxide to complete the hydrolysis.' However, the precise roles of the ZnII and the serine OH group in the mechanism of the enzyme catalysis are not very clear and need to be displayed in reactive model systems where the route is well defined. To elucidate possible participation of neighbouring alcohol groups of metal complexes in the catalysis of phosphate ester hydrolysis, we designed a novel model system involving a ZnII complex bearing an alcohol pendant. LI-ZnII was found to be more than lo4 fold more effective in promoting the release of 4-nitrophenol from diethyl(4-nitropheny1)phosphate than L2-ZnII which lacks such an alcohol pendant. This strong rate enhancement by LI-ZnII indicates that the adjacent alcohol group could be involved directly in the reaction. Interestingly, L1-ZnU was also found to promote the transfer of the phosphate group from the substrate to the alcohol group of the ligand. Ligand LI was prepared by the successive treatment of 2,6-bis(bromomethyl)pyridine with 1 equiv. of N-methyl-2-aminoethanol and 1 equiv. of diethylamine in anhydrous acetonitrile.$ L2 was prepared from pyridine-2,6-dicarboxaldehyde according to literature procedures, 10 Both ligands were further purified as their crystalline 3HBr salts. The ZnII complexes were prepared by stirring an aqueous methanolic solution of the ligande3HBr and 1 equiv. of Zn(C10&.6H20, after adjusting the pH to 9 with aq. 1 mol dm-3 NaOH. Evaporation of solvents and recrystallization from aqueous methanol provided the Znll complexes in analytically pure form. Elemental analyses showed that both complexes are in the dimeric form. A pH titration of an aqueous solution of L1.3HBr in the presence of an equimolar amount of ZnII showed complex formation at pH 6-9, with simultaneous deprotonation of the pendant alcohol OH when 4 equiv. of the base were added. It is of interest to note that both the alcoholic OH of L1-Znrl and the water of LI-Zn" at the fourth coordination sites of the metal deprotonate readily at 25 "C with pK, values of 8.6 and 8.7, respectively. At 25 "C and pH 6-9, the dimerization constants of LI-ZnII and L2-ZnI* are 0.8 and 1.1 dm3 mol-1, respectively. These small dimerisation constants mean that in aqueous solution the metal complexes exist mainly in monomeric form. Such results are consistent with the characteristics of other polyamine-ZnII complexes.llJ2 The lower dimerization con

Traditional chemistry laboratory courses have a manual consisting of “step-by-step”
experiments; instructions are given to complete experiments, requiring minimal
information/concepts processing to be successful. This experience leaves students unprepared for
the real-world, where critical thinking skills are needed to conduct research. This study focused
on building analytical techniques, conceptual knowledge, and critical thinking skills used to
solve research problems. A new quantitative chemistry laboratory manual was developed to
transition students from traditional to inquiry-based experiments, requiring analytical method
development. Data showed students having less difficulty using the new manual (0.8281 average
difficulty) on method development exam questions and experiments, compared to the traditional
manual (0.600 average difficulty). T-test showed significant difference between item difficulty,
p = 0.029. Using null hypotheses, the new laboratory manual led to an increase in students’
conceptual knowledge and research skills. They were able to use their knowledge and skills to
successfully solve real-world related problems.

This study was designed to optimize three microwave-assisted extraction (MAE) parameters (ethanol concentration, microwave power, and extraction time) of total phenolics, total flavonoids, and antioxidant activity of avocado seeds using response surface methodology (RSM). The predicted quadratic models were highly significant (p<0.001) for the responses studied. The extraction of total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity was significantly (p<0.05) influenced by both microwave power and extraction time. The optimal conditions for simultaneous extraction of phenolic compounds and antioxidant activity were ethanol concentration of 58.3% (v/v), microwave power of 400 W, and extraction time of 4.8 min. Under these conditions, the experimental results agreed with the predicted values. MAE revealed clear advantages over the conventional solvent extraction (CSE) in terms of high extraction efficiency and antioxidant activity within the short...

Sesame is a nutritional agricultural product with medicinal properties. Accurate determination of micronutrients is important for the improvement of sesame quality and nutrition assessments. Our previous study showed that 10 antioxidants-d-homoproline, vitamin B 2 , coniferyl aldehyde, hesperidin, phloretin, N-acetyl-l-leucine, l-hyoscyamine, ferulic acid, 5-methoxypsoralen, and 8-methoxypsoralen-in sesame were potential characteristic nutrients in sesame. Herein, simultaneous detection of 10 different types of antioxidants was developed by using ultrasound-assisted extraction coupled with liquid chromatography-tandem mass spectrometry (UAE-LC-MS/MS) with the help of response surface methodology. The significant variables and levels were screened and optimized by combining the single factor experiment, Plackett-Burman test, and Box-Behnken design. The optimal conditions for extraction of target antioxidants in sesame were methanol solution of 75.0%, liquid-to-material ratio of 20:1 (mL/g), extraction temperature of 50 • C, extraction power of 410.0 W, extraction time of 65 min. The total yield of targets was 21.74 µg/g under the optimized conditions. The mobile phase used was 0.1% formic acid in acetonitrile and 0.1% formic acid in water, and the column was a Thermo Syncronis C18 reverse phase column (100 mm × 2.1 mm, 3 µm). All targets required only one injection and could be quickly separated and assayed within 7 min. The limits of detection and limits of quantification for these 10 nutritional compounds ranged from 0.01 to 0.11 µg/kg and from 0.04 to 0.34 µg/kg, respectively. The validation results indicated that the method had reasonable linearity (R 2 ≥ 0.9990), good recoveries (71.1%-118.3%), satisfactory intra-day precision (≤9.6%) and inter-day precision (≤12.9%), and negligible matrix effects (≤13.8%). This simultaneous quantification method was accurate, fast, and robust for the assessment of sesame nutrition.

Aims: Alpha (α)-amylase inhibitors from plants are preferable for type 2 diabetes treatment because of their relative potency and safety. This study examined, in vitro, the inhibitory effect of Anthocleista nobilis leaf extract on starch hydrolysis catalyzed by α -amylase (extracted from moated sorghum).  Place and Duration of Study: Department of Biochemistry (School of Biological Sciences) and Department of Chemistry, School of Physical Sciences, University of Cape Coast, Ghana, between June 2021 and August 2021. Methodology: Leaves of A. nobilis were air-dried, pulverized, and macerated in 70% aqueous ethanol for 72 hrs. The filtrate was concentrated and reconstituted in 0.02M Sodium phosphate buffer (pH 6.9) for further analysis including Phytoconstituents screening. In vitro analysis of α -amylase activity as well as inhibitory effect of A. nobilis extract on α -amylase was performed. The Lineweaver-Burk plot was employed in the inhibition analysis to determine the inhibition t...

h i g h l i g h t s First diazonium (perfluoroalkyl) benzenesulfonimide monomer. A new kind of nanoscale material to improve the interface between electrolyte and electrode. Detailed characterizations of all intermediates and the final monomer. Catalytic reduction nitroaromatics without affect perflourovinyl ether group.