Alpha-amylase inhibition kinetics by caulerpenyne

Many algae have important secretions which are generally used for defensive purposes. These secretions take attentions of a lot of researchers who are wondering if these metabolites can be used for medical researches or not. Among these metabolites, caulerpenyne (CYN) which is the main metabolite of Caulerpa species, have had an important place in Caulerpa researches since the results related to its determined properties such as cytotoxic, antiviral, antiproliferative and apoptotic effects have been proven by many scientific reports. In the present study, the inhibitory effect of CYN isolated from C. prolifera on alpha-amylase was investigated. The inhibition experiments were done with CYN by spectrophotometric determination method. In order to evaluate the type of inhibition Lineweaver–Burk plot was produced. The results obtained from enzyme kinetic studies exhibited an un-competitive type of inhibition, which is characterized by the difference of Vmax and KM from those of the free enzyme, of alpha-amylase in the presence of CYN. The present study showed that Caulerpa species can be a potential target for producing diabetic drugs in the light of the results obtained for CYN

Synthesis, acid properties and catalysis by niobium oxide nanostructured materials

Several forms of niobium oxide were prepared, including nanostructured mesoporous materials, and their acidity properties were comprehensively investigated and compared with commercially available materials. The composites were characterized by a variety of techniques, including XRD, TEM, N-2 adsorption and Hammett acid indicator studies. The acidity of the niobium oxide derivatives was also investigated by the ability of the materials to successfully promote the halochromic ring-opening of an oxazine-coumarin probe that was specifically designed for use in fluorescence imaging studies. The ring-opening reaction was easily monitored using UV-visible, fluorescence and NMR spectroscopy. Single molecule microscopy was employed to gain a more in-depth understanding of the niobium oxide acid catalysis pathway. Using this technique, the rate of niobium oxide mediated protonation was estimated to be 1.8 x 10(-13) mol m(-2) s(-1). Single molecule analysis was also used to obtain a detailed map of Bronsted acid sites on the niobium oxide surface. The active sites, located by multiple blinking events, do not seem to be localized on any area of the material, but rather randomly distributed throughout the solid state surface. As the reaction proceeds, the sites with the highest acidity and accessibility are gradually consumed, making the next tier of acid sites available for reaction. The phenomenon was more closely characterized by using time lapsed reactivity maps.The authors wish to thank the Natural Sciences and Engineering Research Council (NSERC) and the Canada Research Chairs program. The University of Ottawa International Office provided grants to study niobium. M. L. Marin thanks the financial support of the Generalitat Valenciana (BEST/2012/233). Thanks are due to the Government of Canada and NSERC for a Banting Postdoctoral Fellowship to S. Impellizzeri and a Vanier Sholarship to C. Fasciani. S. Simoncelli acknowledges a DFAIT fellowship from ELAP (Emerging Leaders in the Americas Program) to support her visit to Canada.Marín García, ML.; Hallett-Tapley, GL.; Impellizzeri, S.; Fasciani, C.; Simoncelli, S.; Netto-Ferreira, JC.; Scaiano, JC. (2014). Synthesis, acid properties and catalysis by niobium oxide nanostructured materials. Catalysis Science and Technology. 4(9):3044-3052. https://doi.org/10.1039/c4cy00238eS304430524

A novel application of queueing theory on the Caulerpenyne secreted by invasive Caulerpa taxifolia (Vahl) C.Agardh (Ulvophyceae, Caulerpales): a preliminary study

Aquarium originated marine green alga Caulerpa taxifolia was introduced into the Mediterranean Sea accidentally in 1984. This invasion has been negatively affecting the sub-littoral ecosystem of the Mediterranean. One of the important reasons for its success in the Mediterranean is its secondary toxic metabolite called caulerpenyne (CPN). Furthermore, CPN has anti-proliferative and apoptotic activities, therefore, CPN can be considered as a potential native source in cancer therapy. For that reason, modeling this metabolite might be of importance. Increase and decrease of the CPN level before reaching the critical level can be expressed by means of a queueing system in which the number of ‘customers' increases and decreases. In fact, production of CPN shows fluctuations for many environmental reasons, which allow us to apply queueing theory. In the present study, the expected time to reach the maximum caulerpenyne level was analyzed and evaluated using queueing theory

Mechanistic insights into the Nb2O5 and niobium phosphate catalyzed in situ condensation of a fluorescent halochromic assembly

[EN] Solid niobium oxides (Nb2O5 center dot nH(2)O) and niobium phosphate were used as heterogeneous acid catalysts to promote the condensation between a switchable oxazine and a fluorescent coumarin in an aprotic solvent. The catalysts were found to promote the generation of an active methylene from the enamine-based portion of the oxazine, which was followed by a nucleophilic attack on the aldehyde functionality of the coumarin reagent. In the resulting system, the emission of the conjugated fluorophore can be observed at 670 nm and, thus, the processes occurring at the catalyst surface can be monitored in real time by total internal reflection fluorescence microscopy (TIRFM).The authors wish to thank the Natural Sciences and Engineering Research Council (NSERC) and the Canada Research Chairs program. The University of Ottawa International Office provided grants to study niobium. Thanks are due to the Government of Canada and NSERC for a Banting Postdoctoral Fellowship to S. Impellizzeri and a Vanier Scholarship to C. Fasciani. S. Simoncelli acknowledges a DFAIT fellowship from ELAP (Emerging Leaders in the Americas Program) to support her visit to Canada. M. L. Marin thanks the financial support of the Generalitat Valenciana (BEST/2012/233) and the Distinguished Visiting Professor program of the University of Ottawa. We thank Dr. Jose-Carlos Netto-Ferreira of INMETRO (Rio de Janeiro, Brazil) for providing chemicals from CBMM.Impellizzeri, S.; Simoncelli, S.; Fasciani, C.; Marín García, ML.; Hallett-Tapley, GL.; Hodgson, GK.; Scaiano, JC. (2015). Mechanistic insights into the Nb2O5 and niobium phosphate catalyzed in situ condensation of a fluorescent halochromic assembly. Catalysis Science and Technology. 5(1):169-175. https://doi.org/10.1039/C4CY00703DS1691755

FTIR study of the adsorption of ammonia and pyridine on V2O5/MgO catalysts

The adsorption of ammonia and pyridine on the surface of the V2O5/MgO catalysts has been studied for the determination of the Bronsted and Lewis acid sites. The data showed that the catalysts have medium Lewis acidity, but are also weak Bronsted acids, having active hydroxy groups able to interact with pyridine by H-bonding and by protonation. Pyridine is a suitable basic probe for the quantification of the catalysts. 32% V2O5/MgO catalyst is the most acidic catalyst

Possible interactions between antioxidant enzymes and free sialic acids in saliva : a preliminary study on elite judoists

Measurement of antioxidant enzyme activities is of great importance in the evaluation of oxidative stress in human metabolism. Sialic acids are also vital bio-markers for some diseases such as acute myocardial infarction and diabetes. In the present study, antioxidant enzyme activities (SOD, CAT, GSH-Px) and free sialic acid (FSA) levels in saliva were determined before and after training in the elite Turkish judoists (ETJ). According to the results, antioxidant enzyme activities in post-exercise values were significantly (p < 0.05) higher than those of pre-exercise values. A major finding of this study was that FSA levels also increased significantly (p < 0.05). Superoxide radical anion might have been effectively dismutated to hydrogen peroxide by elevated SOD activity. Accordingly, it suggests that CAT, having a higher increasing rate, was more efficient than GSH-Px in decomposition of hydrogen peroxide. In conclusion, the increase in antioxidant enzyme activities might have caused the elevation of FSA levels after training. Over-excreted sialic acids to saliva might have an important role in the removal of hydrogen peroxide. Since the increase in FSA levels in saliva has been found to be in well accordance with antioxidant enzymes, FSA may be concluded as an alternative oxidative stress marker in athletes

A Low Cost Immobilization Agent From an Invasive Marine Alga: Caulerpa racemosa var. cylindracea Biomass In Bovine Serum Albumin Immobilization

Objectives: Caulerpa racemosa var. cylindracea is a marine green alga which has been widely invading sublittoral ecosystem of the Mediterranean Sea since 1991. Inasmuch as there is no eradication method related to this species so far, use of the dried biomass of C. racemosa for immobilization of bovine serum albumin was studied in the present study

A study of equilibrium and FTIR, SEM/EDS analysis of trimethoprim adsorption onto K10

The sorption behavior of K10, a type of montmorillonite for trimethoprim (TMP) drug, was studied by using batch technique under different pH and temperature. The interaction between K10 and TMP was investigated using SEM, and FTIR. It was observed that adsorption was increased between pH 2.5 and 6.3. By performing kinetic experiments, the pseudo-second-order kinetic model provides the best fit for TMP adsorption onto K10 montmorillonite. The sorption of TMP reached the equilibrium state after 6 h sorption time and has been described by using Langmuir, Freundlich and Dubinin-Radushkevich equations to obtain adsorption capacity values. The results indicate that the relative adsorption capacity values (K-f) are decreasing with the increase of temperature in the range of 298318 K. The sorption energy values obtained from DR isotherm show that sorption of TMP onto K10 can be explained by ion exchange mechanism at 298, 308 and 318 K. The thermodynamic studies were conducted to find the thermodynamic parameters Delta H degrees, Delta S degrees and Delta G degrees. It was determined that adsorption process is spontaneous and exothermic in nature. (c) 2006 Elsevier B.V. All rights reserved