Metal Ions Zn Research Articles

Synthesis, spectral characterization, molecular modeling and antimicrobial activity of new potentially N2O2 Schiff base complexes

Metal complexes of a new potentially tetradentate symmetrical Schiff base ligand (H2L) with Cu(II), Ni(II), Co(II), VO(IV), Zn(II), Cd(II), Ce(III), Fe(III) and UO2(VI) metal ions have been synthesized and characterized based on their elemental analyses, spectral (IR, UV–Vis, 1H NMR and mass spectra), magnetic and molar conductance studies as well as thermal gravimetric analysis (TGA). The synthesized complexes have the general formula [MHxL(H2O)yXn]: x=0–1, y=0–4 and n=0–1; where: L=dianion of 6-hydroxy-5-[N-(2-{[(1E)-1-(6-hydroxy-2,4-dioxo-3,4-dihydro-2H-1,3-thiazin-5-yl)ethylidene]amino}ethyl) ethanimidoyl]-2H-1,3-thiazine-2,4(3H)-dione and X=nitrate or sulphate anion. The ligand behaves as diabasic tetradentate N2O2 sites, except in cases of Co(II), VO(IV) and UO2(VI) metal ions, it behaves as monobasic tetradentate Schiff base ligand. The metal complexes exhibited square planar, square-pyramidal and octahedral geometrical arrangements except for Ce(III) and UO2(VI) complexes, they are octa-coordinated. The Coats-Redfern equation was used to calculate the kinetic and thermodynamic parameters for the different thermal decomposition stages of some complexes. Structural parameters of the ligand and its metal complexes have been theoretically computed on the basis of semiemperical PM3 level, and the results were correlated with their experimental data. The antimicrobial activities of the ligand and its metal complexes were tested against some Gram-positive and Gram-negative bacteria; and fungus strain and the results were discussed.

Unique Photophysical Behavior of 2,2′-Bipyridine-3,3′-diol in DMSO–Water Binary Mixtures: Potential Application for Fluorescence Sensing of Zn2+ Based on the Inhibition of Excited-State Intramolecular Double Proton Transfer

In this work we have investigated the anomalous behavior of DMSO-water binary mixtures using 2,2'-bipyridine-3,3'-diol (BP(OH)2) as a microenvironment-sensitive excited-state-intramolecular-double-proton-transfer (ESIDPT) probe. Here we present results on the UV-vis absorption and fluorescence properties of BP(OH)2 in the binary solutions. DMSO-water binary mixtures at various compositions are an intriguing hydrogen bonded system, where DMSO acts to diminish the hydrogen bonding ability of water with the dissolved solutes. As a result, we observe unusual changes in the photophysical properties of BP(OH)2 with increasing DMSO content in complete correlation with the prior simulation and experimental results on the solvent structures and dynamics. The fluorescence quantum yield and fluorescence lifetime of BP(OH)2 depend strongly on the DMSO content and become maximum at very low mole fraction (∼0.12) of DMSO. The anomalous behavior at this particular region likely arises from the enhanced pair hydrophobicity of the medium as demonstrated by Bagchi and co-workers (Banerjee, S.; Roy, S.; Bagchi, B. J. Phys. Chem. B 2010, 114, 12875-12882). In addition we have also shown the utilization of BP(OH)2 as a potential Zn(2+)-selective fluorescent sensor in a 1:1 DMSO-water binary mixture useful for biological applications. We observed highly enhanced fluorescence emission of BP(OH)2 selectively for binding with the Zn(2+) metal ion. Moreover, the fluorescence emission maximum of BP(OH)2-Zn(2+) is significantly blue-shifted with a reduced Stokes shift due to the inhibition of the ESIDPT process of BP(OH)2 through strong coordination.

Effect of metal ion (Zn2+, Bi3+, Cr3+, and Ni2+)-doped CdS/halloysite nanotubes (HNTs) photocatalyst for the degradation of tetracycline under visible light

CdS/halloysite nanotube (HNT) samples doped with several metal ions (Mn+-CdS/HNTs, where Mn+ = Zn2+, Bi3+, Cr3+, and Ni2+) were synthesized using a facile and effective hydrothermal method. The as-prepared photocatalysts were characterized by scanning electron microscopy, transmission electron microscopy, X-ray energy dispersive spectroscopy, X-ray diffraction, UV–vis diffuse reflectance spectra, inductively coupled plasma-atomic emission spectroscope, X-ray photoelectron spectroscopy, and Fourier transform infrared. The photocatalytic activity of the Mn+-CdS/HNTs photocatalyst was evaluated by the degradation of tetracycline under visible-light irradiation. The optimum Mn+-doping amount was investigated in detail. At last, the possible photodegradation mechanism for metal-ion-doping photocatalyst was further discussed.

Simultaneous detection of multiple DNA targets based on encoding metal ions

We present a novel strategy for simultaneous electrochemical detection of multiple DNA targets based on the use of different encoding metal ions as tags. The principle of this scheme is that metal ions bound to metallothionein (MT) molecules can be released down after hybridization with DNA targets and then be detected by stripping voltammetry. The novel detection probes, ssDNA/MT conjugates, covered with different metal ions were synthesized for the first time, then three encoding metal ions (Zn2+, Cd2+, and Pb2+) were used to differentiate the signals of three virus DNA due to their well-defined anodic stripping peaks at −1.13V (Zn), −0.78V (Cd), and −0.52V (Pb) at BiFE, respectively. The anodic peak currents increased linearly with the concentrations of DNA targets in the range from 0.1nM to 10nM with a detection limit of 33pM. In addition, the one-base mismatched target was effectively discriminated from the complementary target. The described results demonstrated that this method possesses high sensitivity and selectivity for multi-target DNA assay and has great potential in applications for detection of even more targets in biological assays, particularly immunoassays.

A role for synaptic zinc in ProSAP/Shank PSD scaffold malformation in autism spectrum disorders

The establishment and maintenance of synaptic contacts as well as synaptic plasticity are crucial factors for normal brain function. The functional properties of a synapse are largely dependent on the molecular setup of synaptic proteins. Multidomain proteins of the ProSAP/Shank family act as major organizing scaffolding elements of the postsynaptic density (PSD). Interestingly, ProSAP/Shank proteins at glutamatergic synapses have been linked to a variety of Autism Spectrum Disorders (ASDs) including Phelan McDermid Syndrome, and deregulation of ProSAP/Shank has been reported in Alzheimer's disease. Although the precise molecular mechanism of the dysfunction of these proteins remains unclear, an emerging model is that mutations or deletions impair neuronal circuitry by disrupting the formation, plasticity and maturation of glutamatergic synapses. Several PSD proteins associated with ASDs are part of a complex centered around ProSAP/Shank proteins and many ProSAP/Shank interaction partners play a role in signaling within dendritic spines. Interfering with any one of the members of this signaling complex might change the output and drive the system towards synaptic dysfunction. Based on recent data, it is possible that the concerted action of ProSAP/Shank and Zn2+ is essential for the structural integrity of the PSD. This interplay might regulate postsynaptic receptor composition, but also transsynaptic signaling. It might be possible that environmental factors like nutritional Zn2+ status or metal ion homeostasis in general intersect with this distinct pathway centered around ProSAP/Shank proteins and the deregulation of any of these two factors may lead to ASDs.

Fractional Derivatives for Description of Sorption Kinetics in the Plant Sorbent - Metal Ions System

Abstract It was examined if buckwheat hull has a potential to be used to adsorb heavy metal ions Zn(II), Cd(II), Co(II), Cu(II), Ni(II) from water. The research involved experiments aimed at the determination of sorption kinetics taking into consideration changes of concentration in a solution and sorbent over time. According to the literature data, kinetics is described with the use of pseudo first-order equations. Application of fractional derivatives for the description of sorption kinetics enables the development of the generalised sorption kinetics equation. Result analysis with this concept requires making a computational procedure using gamma functions and infinite series. Kinetics description using fractional derivatives will be equations with two parameters ie fraction of derivative α and the kinetics constant K dependent on the analysed sorbent-adsorbate system.

Functionalized Porphyrins as Red Fluorescent Probes for Metal Cations: Spectroscopic, MALDI-TOF Spectrometry, and Doped-Polymer Studies.

The sensing ability of benzoporphyrins 1-5 and porphyrin-2-ylpyridines 6-10 towards different metal ions Na+ , K+ , Ca2+ , Mg2+ , Pb2+ , Cu2+ , Ni2+ , Zn2+ , Cd2+ , Hg2+ , and Cr3+ was explored in solution by absorption and fluorescence spectroscopy. Strong changes in the ground and excited state were detected only in the case of the soft metal ions Zn2+ , Cd2+ , Hg2+ , and Cu2+ . A one metal per ligand molar ratio was obtained in all cases for compounds 1-5. In addition, a remarkable increase of the emission intensity for 1-5 was observed in the presence of Hg2+ . In this series the highest association constant was obtained for compound 1 (log Kass =(8.71±4.81)×10-3 ), which was able to quantify 32 ppb of Hg2+ . For compounds 6-10 containing an additional pyridine unit, a metal-to-ligand stoichiometry of 1:2 was determined. The gas-phase detection abilities of compounds 1-10 using MALDI-TOF-MS spectrometry confirmed that their sensorial ability and theoretical calculations are in accordance with the stoichiometry observed. Our preliminary studies show that some of the compounds supported in polymethylmethacrylate (PMMA) films can be used as promising metal-ion solid chemosensors; it was found that compound 1 in PMMA is able to distinguish between Zn2+ and Hg2+ in the solid phase.

Synthesis, characterization and crystal structure of some new Mn(II) and Zn(II) macroacyclic Schiff base complexes derived from two new asymmetrical (N5) branched amines and pyridine-2-carbaldehyde or O-vaniline and their antibacterial properties

Two new branched pentadentate amines (N5), 3,6-bis(2-pyridylmethyl)-5 methyl-3,6-diazaheptane diazahexane-1-amine (1) and 4,7-bis(2-pyridylmethyl)-6-methyl-4,7-diazaheptane-1-amine (2) have been prepared. These have been used for the synthesis for the eight new macroacyclic Schiff base complexes, by template [1 + 1] condensation of pyridine-2-carbaldehyde or O-vaniline and amines (1 and 2) in the presence of Mn(II) and Zn(II) metal ions in methanol. The isolated complexes were characterized by a combination of microanalysis, IR and Mass spectroscopy. The structure of MnL1(ClO4)2 indicates that in the solid state the Mn(II) ion adopts a slightly distorted octahedral geometry. The synthesized compounds have antibacterial activity against the three Gram-positive bacteria: Enterococcus faecalis, Bacillus cereus and Staphylococcus epidermidis and also against the three Gram-negative bacteria: Citrobacter freundii, Enterobacter aerogenes and Salmonella typhi. The structure of the complexes derived from pyridine-2-carbaldehyde and metal–ligand interactions in these complexes were also theoretically studied. It was indicated that the structure of complexes is similar to each other and metal–ligand interactions depend mainly on the nature of metal ion and is similar for this series of ligands.

Interaction between Histidine and Zn(II) Metal Ions over a Wide pH as Revealed by Solid-State NMR Spectroscopy and DFT Calculations

The interactions between histidine and metal species play essential roles in a wide range of important biological processes including enzymes catalysis and signal transduction. In this work, solid-state NMR techniques were employed to determine the interaction between histidine and Zn(II) from pH 3.5 to 14. 2D homo- and heteronuclear correlation NMR experiments were utilized to extract the (1)H, (13)C, and (15)N chemical shifts in various histidine-Zn(II) binding complexes. Several histidine-Zn(II) binding models were proposed on the basis of experimental results as well as DFT theoretical calculations. No direct interaction could be found between biprotonated histidine and Zn(II) at acidic pH. At pH 7.5, one zinc ion could be hexa-coordinated with two histidine molecules on C', Nα and deprotonated Nδ1 sites. As the pH increases to 11-14, both of the Nδ1 and Nε2 sites could be deprotonated as acceptors to be bound to either Zn(II) or water. All of these findings give a comprehensive set of benchmark values for NMR parameters and structural geometries in variable histidine-Zn(II) binding complexes over a wide pH range and might provide insights into the structure-property relationship of histidine-metal complexes in biological metalloproteins.

Kinetic study of formation/dissociation of Cu(II) and Zn(II) complexes of cyclen macrocyclic ligand with pendant thiol group

The kinetic properties of macrocyclic ligand 2-[1,4,7,10–tetraazacyclododecane-1-yl]-ethanethiol (L1, DOSH) were studied with Cu(II) and Zn(II) metal ions, using conventional molecular absorption spectroscopy in pH regions 2.5–4.7 and 4.3–6.0 for Cu(II) and Zn(II), respectively. The obtained partial rate constants, measured at 25°C and ionic strength I=0.1M (KCl), are slightly lower than for parent cyclen (1,4,7,10-tetraazacyclododecane) macrocyclic ligand supporting the hypothesis that the thiol pendant arm is not directly involved in the formation of these metal complexes. The study of the dissociation of the copper(II)-L1 complex in the presence of perchloric acid and at higher temperatures (75–95°C) showed that this complex is more kinetically inert than the copper(II) complex with cyclen, indicating that the presence of the thiol pendant arm plays a key role as protecting group of copper(II) ion. On contrary, the dissociation of zinc(II) complex in presence of copper(II) ion measured at laboratory temperature (25°C) and in 0.1M-solution of hydrochloric acid is going via the metal-exchange reaction mechanism. Altogether, these findings show that L1 ligand presents favorable kinetic properties for further conjugation with biomolecules, aiming at their use in medicinal chemistry.

Use of electroplating sludge for ceramic brick manufacture

The migration of heavy metal ions (Zn2+, Cu2+, Cr3+, Cr6+, Ni2+, Fe2+ and Fe3+) from ceramic brick containing sludge from electroplating is investigated. The laws of migration of chemical elements under the action of different factors (temperature and time of exposure, pH of model medium) in relation to the batch and chemical composition of the bodies as well as the structure and phase composition of the materials are established. The optimal content of sludge in the bodies for obtaining ceramic brick, completely satisfying the regulatory requirements regarding the migration of chemical elements, is determined.

English

  The thiaminase enzymes were partially purified and characterized from Tilapia zillii fillet (flesh) and liver using ammonium sulphate precipitation. The enzyme showed specific activities of 5.20 and 1.17 umol/min/mg of protein respectively for T. zillii fillet and liver. The enzymes exhibited a maximal activity at pH 5.0 and 7.0 for the liver and fillet, respectively. The Michealis constant for thiamine as substrate for both tissues was of 0.4 mM but 0.5 mM and 22 mM were obtained for aniline as substrate in the liver and fillet respectively. The optimum temperature of T. zillii thiaminases were 50 and 85°C for fillet and liver, respectively. Amino acids of fillet did not show significant effect on the enzyme activity but in the liver, the amino acids showed great inhibition with lysine showing complete inhibition of the enzyme. The thiaminase activities of fillet and liver were inhibited by divalent metal ions (Zn2+, Sn2+, Mg2+ and Hg2+) but the enzyme from the liver was completely inhibited by Mg2+. The inhibitors (2-Mercaptoethanol, ethylenediaminetetraacetic acid (EDTA), reduced glutathione (GSH), citrate and ascorbic acid) also showed different inhibitory effects on the enzymes from both tissues. EDTA and ascorbic acid did not inhibit the fillet thiaminase enzyme.   Key words: Tilapia zillii, liver, fillet, thiaminase, characterization, kinetic properties.

Biosorption of Cr(VI) and Zn(II) ions from aqueous solution onto the solid biodiesel waste residue: mechanistic, kinetic and thermodynamic studies

In this present study, the biosorption of Cr(VI) and Zn(II) ions from synthetic aqueous solution on defatted J atropha oil cake (DJOC) was investigated. The effect of various process parameters such as the initial pH, adsorbent dosage, initial metal ion concentration and contact time has been studied in batch-stirred experiments. Maximum removal of Cr(VI) and Zn(II) ions in aqueous solution was observed at pH 2.0 and pH. 5.0, respectively. The removal efficiency of Cr(VI) and Zn(II) ions from the aqueous solution was found to be 72.56 and 79.81%, respectively, for initial metal ion concentration of 500 mg/L at 6 g/L dosage concentration. The biosorbent was characterized by Fourier transform infrared, scanning electron microscopy and zero point charge. Equilibrium data were fitted to the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models and the best fit is found to be with the Freundlich isotherm for both Cr(VI) and Zn(II) metal ions. The kinetic data obtained at different metal ion concentration have been analysed using the pseudo-first-order, pseudo-second-order and intraparticle diffusion models and were found to follow the pseudo-second-order kinetic model. The values of mass transfer diffusion coefficients (De) were determined by Boyd model and compared with literature values. Various thermodynamic parameters, such as ΔG°, ΔH° and ΔS°, were analysed using the equilibrium constant values (Ke) obtained from experimental data at different temperatures. The results showed that biosorption of Cr(VI) and Zn(II) ions onto the DJOC system is more spontaneous and exothermic in nature. The results indicate that DJOC was shown to be a promising adsorbent for the removal of Cr(VI) and Zn(II) ions from aqueous solution.

Coordination Polymers Built with a Linear Bis-Imidazole and Different Dicarboxylates: Unusual Entanglement and Emission Properties

The linear linker bis(4-imidazol-1-ylphenyl)diazene (L) has been used to construct eight new coordination polymers with Zn(II), Cd(II) and Co(II) metal ions and different carboxylate donor ligands, viz., 1,1′-ferrocenedicarboxylic acid (H2Fc), 2′,5′-dimethylterphenyl-4,4″-dicarboxylic acid (H2MDA), diphenic acid (H2DPA), biphenyl-4,4′-dicarboxylic acid (H2BIPH), 4,4′-oxybis (benzoic acid) (H2BIOXY), l-(−)-malic acid (H3LMA) and 2,2′-dibromo-6,6′-dinitrobiphenyl-4,4′-dicarboxylic acid (H2DBDPA). Compounds formed solvothermally are {[Cd(L)(Fc)(H2O)]·(H2O)2}n (1), {[Cd(L)(MDA)]·DMF·CH3OH}n (2), {[Zn(L)(MDA)]·3H2O}n (3), {[Cd(L)(DPA)]}n (4), {[Cd2(L)2(BIPH)2(H2O)2]·H2O}n (5), {[Cd2(L)2(BIOXY)2]·H2O·CH3OH}n (6), {[Zn3(L)5(LMA)2]·2.5H2O}n (7) and {[Co(L)(DBDPA)]·H2O}n (8). All the complexes have been characterized by single crystal X-ray diffraction, IR spectroscopy, thermogravimetry, elemental analysis and powder X-ray diffraction (PXRD). Interestingly, all complexes topologically exhibit 4-connected net excep...

Zinc regulates the activity of kinase-phosphatase pair (BasPrkC/BasPrpC) in Bacillus anthracis

Bacillus anthracis Ser/Thr protein kinase PrkC (BasPrkC) is important for virulence of the bacterium within the host. Homologs of PrkC and its cognate phosphatase PrpC (BasPrpC) are the most conserved mediators of signaling events in diverse bacteria. BasPrkC homolog in Bacillus subtilis regulates critical processes like spore germination and BasPrpC modulates the activity of BasPrkC by dephosphorylation. So far, biochemical and genetic studies have provided important insights into the roles of BasPrkC and BasPrpC; however, regulation of their activities is not known. We studied the regulation of BasPrkC/BasPrpC pair and observed that Zn(2+) metal ions can alter their activities. Zn(2+) promotes BasPrkC kinase activity while inhibits the BasPrpC phosphatase activity. Concentration of Zn(2+) in growing B. anthracis cells was found to vary with growth phase. Zn(2+) was found to be lowest in log phase cells while it was highest in spores. This variation in Zn(2+) concentration is significant for understanding the antagonistic activities of BasPrkC/BasPrpC pair. Our results also show that BasPrkC activity is modulated by temperature changes and kinase inhibitors. Additionally, we identified Elongation Factor Tu (BasEf-Tu) as a substrate of BasPrkC/BasPrpC pair and assessed the impact of their regulation on BasEf-Tu phosphorylation. Based on these results, we propose Zn(2+) as an important regulator of BasPrkC/BasPrpC mediated phosphorylation cascades. Thus, this study reveals additional means by which BasPrkC can be activated leading to autophosphorylation and substrate phosphorylation.

Solvothermal syntheses, crystal structures, thermal and photoluminescent properties of four coordination polymers constructed from mercapto-thiadiazole ligand

By combining one kind of N-/S-containing rigid ligand with metal ions Zn(II), Co(II), Ni(II) and Pb(II), we have solvothermally synthesized four mercapto-thiadiazole based coordination polymers: [Zn(3-ptt)2]n (1), [Co(3-ptt)2]n (2), [Ni(3-ptt)2]n (3) and [Pb(3-ptt)2] (4) (3-pttH=2-(3-pyridine)-1H-1,3,4-thiadiazole-5-thioketone). As a result of various coordination modes of the versatile 3-ptt, four complexes exhibit structural diversity. 1 and 2 exhibit similar novel twofold interpenetrating 3D supramolecular framework with 66-dia topology embodying two types of left- and right-handed single-helical chains, 3 displays an attractive interconnected 1D chain structure and 4 presents a mononuclear structure. We also investigated their thermogravimetric (TG) and luminescent properties. Complexes 1 and 4 show different luminescence properties in solid state at room temperature and may be suitable as a candidate for potentially photoactive material.

SCREENING AND CHARACTERIZATION OF L-GLUTAMINASE PRODUCED BY BACTERIA ISOLATED FROM SANGIHE TALAUD SEA

L-glutaminase (L-glutamine amidohydrolase, EC 3.5.1.2) is a very important enzyme due to its role as flavor enhancer and antileukemic agent. Salt-tolerant L-glutaminase produced bymarine bacteria is favorable in food industries. This study describes the screening of L- glutaminase producing marine bacteria from Sangihe-Talaud Sea, North Sulawesi, Indonesia.Screening of L-glutaminase was performed using a liquid medium and identification of selected isolate was performed using molecular-based 16S rDNA. Results showed that there were 7 isolates produced positive results of L-glutaminase, and one of them (II.1 isolate) produced the highest activity, i.e 147.99 U/L, equivalent to the specific activity of 62.32 U/mg. The isolate then selected for further study. Bacterial identification based on 16S rRNA sequencing has revealed that the isolate was 96% similar to Pseudomonas aeruginosa strain CG-T8. Characterization of extracellular L-glutaminase from the II.1 isolate showed that the enzyme worked optimally at temperature of 37-45 °C and pH 7. The enzyme was stable when NaCl solution was added up to 8% and began to decrease on addition of NaCl solution of 16% and 20% with relative activity of 79% and 74%, respectively. The effect of metal ions, e.g Mn2+, Mg2+, and Co2+ in the form of chloride salt, were able to increase enzyme activity, whereas the addition of other metal ions (Zn2+, Fe3+, and Ca2+) decreased the activity. The molecular weights of L-glutaminase was estimated around42 kDa and 145 kDa.

Abstract 5306: Tissue-specific prostate specific antigen (PSA).

Abstract We attempted to isolate and characterize PSA from prostate tissue. The aim was to isolate tissue-specific PSA and its initial characterization. This included: (i) determination of PSA molecular forms (free and complexed PSA), (ii) enzymatic activity, and its inhibition by metal ions, (iii) and their relative anti-angiogenic activity. Prostate, tumor and non-tumor, tissue was acquired under IRB approved protocol. PSA was isolated from prostate non-tumor (NT-PSA) and tumor tissue (T-PSA) and characterized using various chromatographic techniques including ligands such as Thiophilic gel, Concanavalin-A agarose, Protein-A agarose, and other lectins. The average NT-PSA concentration was 25±6.3ng PSA/μg of DNA (p=0.0001) and the average T-PSA concentration was 13±5.7ng PSA/μg of DNA (p=0.0001). On an average, tumor PSA (EA=29.64±11.34 p=0.0001)) had twice as much enzymatic activity as compared to non-tumor PSA (EA=13.29±3.300 p=0.001). The inhibition of enzymatic activity of PSA by metal ion (Zn2+)showed that seminal plasma-PSA (SP-PSA) and NT-PSA were inhibited to the same degree [85.3% and 87.0% respectively (p<0.05)]. However, the level of EA of T-PSA was significantly lower (52.4%) as compared to T-PSA. In regards to its molecular complexes, a higher ratio of free to complex-PSA (ACT and A2M) was obtained from non-tumor prostate tissue-PSA (1.51 p=0.0001) as compared to tumor prostate tissue-PSA (1.15 p=0.0001). Initial studies on the effect of SP-PSA on in vitro angiogenesis revealed a dose-dependent inhibitory effect (1μM, 5μM, 10μM concentrations) on the formation of tubular structures in HUVEC-Matrigel assay. The inhibitory effect of T-PSA & NT-PSA was examined and compared to the effect obtained from SP-PSA. Concentrations of 0.1μM, 1μM and 5μM gave similar levels of inhibition for SP-PSA, NT-PSA, and T-PSA (NT-PSA p-values for 1μM and 5μM: p=0.0057, p=0.0006, respectively; T-PSA p-values for 1μM and 5μM: p=0.0038, p=0.0002, respectively). At 0.1 μM concentration, both T-PSA and NT-PSA were not statistically different from control (p=0.3561 and p=0.2532, respectively). A 10μM concentration of both SP-PSA and NT-PSA displayed similar results (p=0.0001). When comparing the effects between NT-PSA and T-PSA, only 0.1μM concentration produced statistically significant results (p=0.0149; 1μM and 5μM: p=0.2301 and p=0.0752, respectively). We found that both NT-PSA and T-PSA also produced significant dose-dependent inhibition (1μM and 5μM NT-PSA and T-PSA (% inhibition): 76.21, 72.58, and 55.07, 54.98, respectively (p<0.05)). A larger sample size is needed to further assess the differences between the two groups. Our results provide some insight into the role of PSA in pathobiology of prostate cancer. PSA levels in prostate cancer tissue are lower as disease progresses suggesting that PSA has a role in prostate pathology. Citation Format: Srikant S. Chakravarthi, Kailash C. Chadha, Gary J. Smith. Tissue-specific prostate specific antigen (PSA). [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5306. doi:10.1158/1538-7445.AM2013-5306

Pengaruh Ion-ion Logam terhadap Aktivitas Pektinase dari Aspergillus niger pada Penjernihan Sari Buah Jambu

Pectinase can be used on various fruit juices clarification; however, the activities can be affected by their metal ions content. The purpose of this study was to determine the type of metal ions inhibition i.e. Zn 2+ ; Mg 2+ and Ca 2+ on the pectinase activity of Aspergillus niger , and its potential application in guava juice clarification. Activity assays performed at pH 5, temperature 50°C during 55minutes and each ion concentration were 2-10 mM. Galacturonic acid concentration, as the product of pectin substrate hydrolysis, used as the basis for determining its activity and analyzed by visible spectrophotometry. The results showed that the ions concentration of Zn 2+ and Mg 2+ more than 4 mM were inhibitor for pectinase activity while Ca 2+ ion concentration was 6mM. K I values for the metal ions Zn 2+ ; Mg 2+ and Ca 2+ at concentrations of 6mM were 176.99; 326.09 and 280.37 mM respectively. Pectinase from Aspergillus niger were able to reduce 18% of pectin of guava juice.

Amino acid absorption by lobster (Homarus americanus) intestine using dual‐label radioisotopic tracer techniques

Amino acids are transported from the lumen of an intestine to the blood across epithelial mucosal and serosal membranes by specific amino acid carrier proteins found within the membrane as well as a transport process involving bis complex formation between the amino acids and metal ions resulting in a dipeptide‐like substrate. In this study the absorption of 3H‐L‐leucine and 35S‐L‐methionine across lobster intestine were simultaneously followed in the presence and absence of Zn metal ions using dual‐label radioisotopic tracer techniques allowing the analysis of independent amino acid fluxes in single experiments. The radiolabelled amino acids were perfused through in vitro lobster intestines and rates of isotope appearance were periodically monitored to estimate trans‐intestinal fluxes of each amino acid. In the presence of luminal Zn, both 3H‐L‐leucine and 35S‐L‐methionine fluxes across the tissue were significantly stimulated. There was no significant evidence that the amino acids competed with each other for carrier transport in the absence of Zn, suggesting separate amino acid transport systems for these substrates. On‐going experiments will determine if bis‐complexes of these amino acids, involving Zn, enhance amino acid flux rates to the serosa, and if there are competitive interactions between the complexes. Agriculture and Food Research Initiative Competitive USDA Grant no. 2010–65206‐20617.