POSTER - Babeș-Bolyai · PDF filePOSTER Table of Contents ... Anitta Puscas1, Mihai Inceu1,...

POSTER Table of Contents POSTER ........................................................................... 0

Ceramic materials functionalized with calix[n]arenes .... 2 Properties of mortars prepared with recycled glass aggregate ....................................................................... 4 Physical and chemical aspects regarding acrylamide formation in the Maillard reaction ................................. 6 Study of honeys adulteration using a new HPTLC validated method ........................................................... 8 Cisplatin effects on physiologically-relevant reactivities of proteins ................................................................... 10 Culture optimization, purification and characterization of phytopathogenic fungus Sclerotinia sclerotiorum laccase .................................................................................... 12 Fingerprinting and antioxidant activity evaluation of twenty-seven Romanian red wines ............................... 14 The Sphericity of the Diverse Ten-Vertex Polyhedra Found in Bare Post-Transition Metal Clusters: Germanium Clusters with Interstitial Magnesium Atoms as Model Systems ........................................................ 16 Use of a non-heme iron peroxidase in hemoglobin and hemerythrin-based blood substitutes ............................ 18 Direct synthesis of ordered mesoporous Fe-SBA-15 materials by “pH-adjusting method” for catalytic Fenton-like oxidations ............................................................. 20 PEGylation of a mutant hemerythrin ............................ 23 for use in blood substitutes .......................................... 23 The influence of variety, vintage year and winery on antioxidant characteristics of some Romanian white wines ........................................................................... 25

9th International Conference “Students for Students” 10-13 May 2012

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Hemoglobin-based copolymers with potential as blood substitutes: increased molecular weight, reduced prooxidant reactivity .................................................... 27 Anthocyanins from Cornelian Cherries (Cornus mas L.). Optimization of the extraction methods ....................... 29 Maillard Reactions and Its Role in Cereal Products ..... 30


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Ceramic materials functionalized with calix[n]arenes

Ranete R., Paic S.

Facultatea de Chimie si Inginerie Chimica, Universitatea Babes-

Bolyai, 11, Arany Janos Street, RO-400028, Cluj-Napoca

The ability of calixarenes to bind through multiple connectivity points, together with the fact that they can selectively host certain metallic ions in their cavity, make them interesting candidates for the functionalization of several types of surfaces. We are interested in obtaining new ceramic based inorganic materials, in which the calixarenes can act as a calibrating system in tuning the dimension of pores on the surface of the material. To this purpose, the absorption of several calyx[n]arenes on porous ceramic masses was attempted, in order to determine their effect on the pore dimensions and other properties of the surface. The derivatives considered are functionalized calix[6] and [8]arenes, bearing –OH, -OMe or –Br groups., like the ones presented in Scheme 1.


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OH OCH3

Br

OCH3

nn n

n = 6, 8 n = 8

Scheme 1

The ceramic microstructure and covering of the ceramic surface by the functionalized calix[n]arenes will be discussed. The authors wish to thank lect. dr. Gabriela Nemes and assoc. conf. dr. Maria Gorea for supervising this work. Financial support from CNCSIS-UEFISCSU(project no. PNII-ID_PCCE_129/2008) is acknowledged.


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Properties of mortars prepared with recycled glass aggregate

Hornea L. Facultatea de Chimie si Inginerie Chimica, Universitatea Babes-

Bolyai, 11, Arany Janos Street, RO-400028, Cluj-Napoca

Due to an increase in industrialization, quantities of waste glass have been on the rise in recent years. A large amount of abandoned cathode ray tube glass causes problems such as waste of natural resources and environmental pollution. A solution is to use such waste as an aggregate in concrete and mortars. This study investigates the properties of mortars, where cathode ray tube glass taken from computer and television monitors (CRT glass), reduced below 4 mm, is used in place of traditional sand aggregates (in proportions of 10%, 20%, 40%, 80% and 100%). The chemical composition shows a 62,04% SiO2, 19,88%BaO, 7,5% Na2O, 7,25% K2O, 1,82% Al2O3, 0,68% CaO and 0,09% Fe2O3 content in oxides. Six mixture recipes were prepared for obtaining mortar prisms (0.16x0.04x0.04 m). The compressive and splitting tensile strength, shrinkage, thermal conductivity, and resistance to sulfate attack of the samples were determined. Results show that compressive strength and tensile splitting strength decrease with an increase in recycled glass aggregate content. The optical microscopy images show a slight attack of acid solution after 28 days.


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The author wish to thank Conf. Maria Gorea for supervising this work.


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Physical and chemical aspects regarding acrylamide formation in the Maillard

reaction

Cãtãlina Teodora STÎNGÃ1 Romicã CREŢU²

1Universitatea “Dunărea de Jos” din Galaţi, Facultatea de Ştiinţa şi Ingineria Alimentelor, Str. Domnească, nr.47

,800008 Galaţi, ROMANIA, e-mail address: [email protected]

2Universitatea “Dunărea de Jos” din Galaţi, Facultatea de Ştiinţe

Acrylamide (or acrylic amide) is a chemical compound with the chemical formula C3H5NO. Its IUPAC name is prop-2-enamide. Acrylamide is a substance produced naturally in foods as a result of high temperatures (eg, baking, grilling and frying). Acrylamide production is favoured in some natural colloidal systems rich in carbohydrates which are treated at high temperatures (above 120 ° C) in the production process or during processing (higher temperature and longer exposure to the temperature generate more acrylamide) Therefore, acrylamide formation occurs during the browning process by the Maillard reaction, which occurs from specific reactions between reducing sugars and amino compounds at temperatures above 120 ° C. Colour products are also formed during pronounced heating of the food based on colloids as a result of the


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Maillard reaction and melanoidins are known to be part of most final products of reaction. These brown products have significant effects on food quality, because color is a very important attribute of food. Brown color formation mechanism is not fully understood and melanoidins structure is largely unknown. Food colloids surface color is an important attribute that can be correlated with the level of acrylamide, as a result of their heat treatment. Information on food surface color, respective on image colour that can be interpreted relatively easily by using Tristimulus Colorimetry method. We determined experimentally that cake yellow brown coloured, presented the highest levels of acrylamide. Thus, in accordance with experimental data, measuring the concentration of acrylamide increases rapidly with sample heating or baking, reaching a maximum concentration after 30 minutes. After that, the concentration of acrylamide in the sample tends to decrease exponentially. The results show that the level of acrylamide in the sample begins to decrease once the degradation speed is higher than the one during baking speed training sample. References: 1. Zyzak D. V. , Sanders R. A. , Stojanovic M, Tallmadge

D, Eberhart B. L. , Ewald D. K. , Gruber D. C., Morsch T. R. , Strothers M. A., Rizzi G. P., Villagran M. D. (2003) Acrylamide formation mechanism in heated foods. Journal of Agricultural and Food Chemistry;

2. Rufian Henares J. A., Arribas-Lorenzo G, Morales F. J. (2007) Acrylamide content of selected Spanish foods: Survey of biscuits and bread derivatives. Food and Contaminants;


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Study of honeys adulteration using a new HPTLC validated method

Anitta Puscas1, Mihai Inceu1, Claudia Cimpoiu1, Anamaria

Hosu1

1 “Babes Bolyai” University, Faculty of Chemistry and Chemical Engineering, 11 Arany Janos 400082 Cluj-Napoca,

[email protected]

Honey is a supersaturated solution of sugars, of which fructose and glucose are the main contributors, with phenolic compounds, minerals, proteins, free amino acids, vitamins etc [1]. It has been used for a long time as a natural source of sugars and as an important ingredient in traditional medicine, for its antimicrobial and antiinflamatory effects [2]. Although, studies on the basic composition of honeys started years ago [3], there are a few studies in literature about the authenticity of them, especially of Romanian ones. There are a few methods of honeys adulteration, but the most common are by adding fructose (and changing the fructose: glucose ratio) or by adding sugar. Our study is concerned on developing and validating a new modern analytical method for detecting the adulteration of some Romanian honeys.

For this purpose, standard solutions of 0.1% of glucose, fructose and sugar were used. The analyzed standards and honey samples (20 µL of each honey -0.1%- from all 15 used) were applied using and semi- automatic applicator device (Camag- Linomat5) as 8 mm bands at 1.2 cm from the low edge, on silica gel HPTLC aluminum sheets. The plates (20x10) were developed at a distance of 80 mm, using a mixture of ethyl acetate- pyridine- water-


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acetic acid, 6: 3: 1: 0.5 (v/v/v/v) as mobile phase. After the development, the dried plate was dipped in an immersion solution and heated at 1100C for 15 min. The solution for detection was prepared by dissolving diphenylamine (2 mg) and aniline hydrochloride (2 mg) in acetone (80 mL), adding phosphoric acid (15 mL) and diluting to 100mL with acetone. The documentation of plates was performed using TLC visualization device (Camag- Digistore2) and the images of plates were processed using Videoscan software.

The developed HPTLC method was validated according to ICH guideline for the following parameters: specificity, linearity, range, LOD, LOQ, precision, robustness and accuracy.

The presented method is a useful tool to identify the adulteration of Romanian honeys on the basis of glucose and fructose ratio and sugar content. The proposed method was found to be simple, precise and accurate and has the advantage of rapidity and economy. This study also provides a reliable set of information regarding adulteration of honey frequently consumed all over the world. Acknowledgements This research is supported by performance scholarship for students no. 30068/15/19.01.2012. References: 1. J. M. Alvarez et al, Food and Chemical toxicology, 48, 2010 2. M. Zalibera et al, Food Chemistry, 110, 2008 3. Suarez et al, Journal of Agricultural and Food Chemistry, 58, 2010


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Cisplatin effects on physiologically-relevant reactivities of proteins

Camelia-Gratiela Tusan, Cristina Bischin, Radu Silaghi-

Dumitrescu Department of Chemistry and Chemical Engineering, “Babes-Bolyai” University, 11 Arany Janos str, Cluj-Napoca RO-400028, Romania One of the most important drugs employed in treating various types of cancers is cisplatin. The use of this drug and its congeners (oxaliplatin and carboplatin) in cancer therapy is accompanied by a variety of adverse affects, such as nephrotoxicity, neurotoxicity, ototoxicity etc. Cisplatin and related compounds are known to bind to several classes of proteins. These interactions are likely to be worth considering among the mechanisms whereby platinum-containing drugs induce toxic side effects in humans[1]. In order to delineate the mechanisms of interaction between proteins and cisplatin we pursue the different parameters which result from interactions with hemoglobin, myoglobin, laccase, catalase, α-amylase, lipase and tyrosinase. Cisplatin was shown to modulate various physiological parameters of hemoglobin such as dioxygen affinity, autooxidation and pro-oxidative reactivity with hydrogen peroxide [2]. One of our working hypotheses is that indeed the interaction between platinum compound and metalloproteins such as hemoglobin and myoglobin can enhance nitrosative stress. It has been shown that nitrite ion is a direct causative agent for methomoglobinemia[3]. Here,


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changes in the UV-Vis spectra show that nitrite-induced oxidation of hemoglobin to methemoglobin under aerobic conditions is affected by platinum anticancer compounds in a concentration-dependent manner. Effects of cisplatin on a few physiologically-relevant enzymatic acticities are investigated as well. It appears that cisplatin affects the reactivities of proteins, although the mechanisms of these processes have not been understood to date.

References: 1. Cristina Bischin, Alexandru Lupan, Vicentiu Taciuc. Interactions between proteins and platinum-containing anti-cancer drugs, Mini-Reviews in Medicinal Chemistry, 2010, 11(3), 214-221 2. C. Bischin, F. Deac, R. Silaghi-Dumitrescu, J.A.R. Worrall, B.S. Rajagopal, G. Damian, C.E. Cooper Ascorbate peroxidase activity of cytochrome c. Free Radical Research, 2011, 45(4), 439-444 3.M. P. Doyle, J. G. Herman, R. L. Dykstra, Autocatalytic oxidation of hemoglobin induced by nitrite: Activation and chemical inhibition. Journal of Free Radicals in Biology & Medicine 1985, 1(2), 145-153


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Culture optimization, purification and characterization of phytopathogenic fungus

Sclerotinia sclerotiorum laccase

Cristina Coman1, Augustin Cătălin Moţ1, Radu Silaghi-

Dumitrescu1

1Babeş-Bolyai University, Faculty of Chemistry and Chemical Engineering,11 Arany Janos str, RO-400028, Cluj-Napoca, România, [email protected]

Laccases are multicopper oxidases (benzenediol oxygen oxidoreductase, E.C. 1.10.3.2) that catalyze the one-electron oxidation of phenolics, aromatic amines, and other electron-rich substrates with the concomitant reduction of O2 to H2O. The laccase produced by the phytopathogenic fungus Sclerotinia sclerotiorum was purified and characterized. In order to obtain the best laccase activity, a culture optimization was performed. The optimum pH value was found to be around 7. Chelidonium majus as well as yeast extracts were proved to be laccase inducers in Sclerotinia sclerotiorum through stress pathways. Purification of the enzyme was performed using ammonium sulfate precipitation, preparative native electrophoresis, DEAE-Sepharose and Phenyl-Sepharose chromatography. UV-vis and EPR spectra were measured and analyzed. The molecular mass of the enzyme was determined to be 60 kDa by SDS-PAGE and the enzyme appeared to be a monomeric glycoprotein. The optimum temperature for activity was 60-70°C, in good agreement with other fungal laccases. The enzyme showed broad


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substrate specificity, and it may therefore be potentially useful for numerous bioremediation or industrial applications.

The purified laccase was assigned to be the putative uncharacterized A7EM18 form Uniprot database by MS analysis. Using the primary structure from this database a 3D model was constructed by the use of (PS)2-v2: Protein Structure Prediction Server using Melanocarpus albomyces laccase 3D structure (2Q9O – pdb code) as template by automatic selection (Figure 1).

Figure 1. Active sites and overall 3D structure of Sclerotinia sclerotiorum laccase model.

References: 1. A. Leontievsky, N. Myasoedova, N. Pozdnyakova, L. Golovleva, FEBS Letters, 413 (1997) 446-448; 2. N. Pozdnyakova, J. Rodakiewicz-Nowak, O.V. Turkovskay, J. Haber, Journal of Molecular Catalysis B: Enzymatic 41 (2006) 8–15; 3. A.C. Mot, M. Pârvu, G. Damian, Z. Darula, K. Medzihradszky, F.D. Irimie, B. Balasz, R. Silaghi-Dumitrescu, Process Biochemistry, in press.


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Fingerprinting and antioxidant activity evaluation of twenty-seven Romanian red

wines

Virgil Danciu1, Mihai Inceu1, Claudia Cimpoiu1, Anamaria Hosu1,


[email protected]

Many epidemiological studies have shown a correlation between a non-well-balanced diet and coronary heart diseases, a few types of cancer and diabetes [1]. Epidemiologists have observed that a diet rich in polyphenolic compounds may provide a positive effect due to their antioxidant properties [2]. The polyphenolic contents of wine consist in flavonoids, anthocyanins and stilbens and depend on the grape variety, vineyard location, cultivation system, climate, soil type, vine cultivation practices, harvesting time, production process and ageing [3].

The aim of this study is to obtain the chromatographic fingerprint and the antioxidant activity evaluation of twenty-seven Romanian red wines and to evaluate their dependency on the vintage and on the grape variety.

The chromatographic fingerprinting was obtained by elution of silica gel 60F254 HPTLC aluminum sheets (20x10cm) with ethyl acetate – formic acid – acetic acid – water, 20 : 2 : 2 : 4 (v/v/v/v) in a pre-saturated twin trough chamber. Detection was performed under UV light at 366nm, before and after the dipping of the plates in the


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NP/PEG solution. The fingerprinting method was validated according to the general validation procedure of qualitative HPTLC method for stability, specificity, precision and robustness. The obtained fingerprints are useful for quality control of wines allowing their differentiation according to the grape varieties, the vintage years and the wineries. The antioxidant activity evaluation of wines was performed by digitally processing of images taken after the plate immersion in the methanolic solution of DPPH for 1s. The antioxidant activity increases in the order Feteasca Neagra, Cabernet Sauvignon, Merlot and the same ranking of wines according to their antioxidant activity can be achieved anytime between 2 and 30min after immersion.

The developed methods are rapid, flexible and enable to distinguish between closely related wines being useful for authentication and quality control of wines. Acknowledgements This research is supported by performance scholarship for students no. 30038/18/19.01.2012. References: 1. Fernàndez-Pachòs, M. S., Villano, D., Garcia-Parrilla, M. C., & Troncoso, A. M. Analitical Chimica Acta, 513, (2004).113–118. 2. Danila Di Majo , Maurizio La Guardia, Santo Giammanco, Laura La Neve, Marco Giammanco Food Chemistry 111 (2008) 45–49 3. Shahidi, F., & Naczk, M.. Pennsylvania: Technomic Publishing Co (1995). 136–148.


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The Sphericity of the Diverse Ten-Vertex Polyhedra Found in Bare Post-Transition Metal Clusters: Germanium Clusters with

Interstitial Magnesium Atoms as Model Systems

Matei-Maria Uţăa, Daniela Cioloboca, Ioan Silaghi-

Dumitrescua†, and Robert Bruce Kingb

aFaculty of Chemistry and Chemical Engineering, Babeş-Bolyai University, 1.Kogălniceanu str., RO-

400084, Cluj-Napoca, Roumania, [email protected]

bDepartment of Chemistry, University of Georgia, Athens, Georgia 30602, USA

Four different 10-vertex bare post-transition element

polyhedra have been found to host interstitial guest atoms in M@E10 structures (Figure 1). A D4d bicapped square antiprism is found to encapsulate a group 10 metal atom in the anionic indium cluster Zn@In10

8– found in the intermetallic[1] K8In10Zn as well as the lead clusters M@Pb10

2– in [K(2,2,2-crypt)]2[M@Pb10] (M = Ni, Pd, Pt).[2,3] This polyhedron is the most spherical ten-vertex deltahedron found in polyhedral boranes such as B10H10

2–. However, in the isoelectronic M@In10

10– clusters found in the K10In10M intermetallics (M = Ni, Pd, Pt) the encapsulating polyhedron is a C3v tetracapped trigonal prism.[4] The pentagonal antiprism is the host polyhedron for an interstitial palladium atom in the cationic bismuth cluster Pd@Bi10

4+ in Bi14PdBr16.[5] The pentagonal prism


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has been found as the host polyhedron for an iron or cobalt atom in the clusters M@Ge10

3– (M = Fe, Co).[6,7] The jellium model has been used to analyze bonding

molecular orbital patterns of model Mg@Ge10z clusters (z =

+2 to –4) representing each of these four 10-vertex polyhedra. Magnesium was chosen to be the interstitial atom since it has a single +2 oxidation state so that it is an unambiguous donor of two valence electrons. Thus Mg@Ge10

2+ clusters are examples of systems with the magic number of 40 total valence electrons (Figure 2), namely two from the central magnesium atoms and four from each germanium atom minus two for the +2 charge. Geometry optimizations were carried out at the hybrid DFT B3LYP level using the Gaussian 03 package of programs. References [1] S.C.Sevov, J.C.Corbett, Inorg. Chem. 1993, 32, 1059. [2] E.N.Esenturk, J.Fettinger, B.Eichhorn, Chem. Comm. 2005, 247. [3] E.N.Esenturk, J.Fettinger, B.Eichhorn, J. Am. Chem. Soc. 2006, 128, 9178. [4] R.W.Henning, J.D.Corbett, Inorg. Chem. 1999, 38, 3883. [5] M.Ruck, V.Dubenskyy, T.Söhnel, Angew. Chem. Int. Ed. 2003, 45, 2978. [6] B.Zhou, M.S.Denning, D.L.Kays, J.M.Goicoechea, J. Am. Chem.Soc. 2009, 132, 2802. [7] J.Q.Wang, S.Stegmaier, T.F.Fässler, Angew Chem. Int. Ed. 2009, 48, 1998.


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Use of a non-heme iron peroxidase in hemoglobin and hemerythrin-based blood

substitutes

Denisa Hathazi1, Augustin C. Mot1 Florina Deac,1 Iulia

Lupan2, Eva Fisher-Fodor,3 Grigore Damian, Donald M.

Kurtz, Jr.,4 Radu Silaghi-Dumitrescu1*

Department of Chemistry and Chemical Engineering1 and

Department of Biology2,”Babes-Bolyai” University, 11 Arany

Janos str, Cluj-Napoca RO-400028, Romania, 3Ion Chiricuta

Cancer Institute - Comprehensive Cancer Center, 34-36

Republicii St., Cluj Napoca 400015, Romania and 4Department

of Chemistry, University of Texas at San Antonio, One UTSA

Circle, San Antonio, Texas 78249-0698, U.S.A.

The non-heme iron peroxidase, rubrerythrin (Rbr),

shows as an interesting feature the ability to reduce hydrogen peroxide without involving strongly-oxidizing and free-radical-creating powerful oxidants such as Compounds I and II (formally Fe(IV) in contrast with heme-containing peroxidases and catalases. Therefore, it may be used as a useful ingredient in protein-based artificial oxygen carriers. Hemoglobin (Hb) and hemerythrin (Hr), can each be co-polymerized with rubrerythrin using gluteraldehyde as cross-linking agent. These co-polymers show additional peroxidase activity


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compared to Hb-only and Hr-only polymers, respectively. Tests on human umbilical vein endothelial cells (HUVEC) reveal slightly better performance of the Rbr co-polymers compared to controls, as measured at 24 hours but not at later times.

Fig.1. The overall fold of the Rbr subunit and detailed view of the iron

centers References:

1. Alayash A.I. Nat Rev Drug Discov, 2004, 3, 152-9. 2. Mot A.C., Roman A., Lupan I., Kurtz D. M. Jr., Silaghi-

Dumitrescu, R. Protein J, 2010, 29, 387-93. 3. Mot A.C, Hathazi D., Deac F., Lupan I., Fischer-Fodor

E., Damian G, Kurtz,D.M., Silaghi-Dumitrescu R., in preparation


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Direct synthesis of ordered mesoporous Fe-SBA-15 materials by “pH-adjusting method”

for catalytic Fenton-like oxidations

Irina Mazilu1, Brindusa Dragoi, Cezar Catrinescu, Adrian Ungureanu and Emil Dumitriu

“Gheorghe Asachi” Technical University of Iasi, Faculty of

Chemical Engineering and Environmental Protection, 67 Prof. D. Mangeron Bvd., Iasi, Romania; [email protected]

Iron-doped ordered mesoporous silicas are emerging as high performance heterogeneous Fenton-like catalysts in the advanced oxidation of bulky molecules from wastewater (e.g., non-biodegradable azo dyes).1 Fe-SBA-15 are among the most sought-after materials due to several advantages: (i) high specific surface area, (ii) hexagonal arrangement of large mesopores (space group p6mm); (iii) narrow pore size distribution and (iv) high (hydro)thermal stability. Nevertheless, the incorporation of iron into the framework of SBA-15 silica by “conventional direct synthesis” is often not straightforward since the too high acidity of the synthesis gel (i.e., pH ~ 0) is not compatible with the formation of Si-O-Fe linkages.2

Herein, we report the synthesis of Fe-SBA15 materials (molar ratio Si/Fegel = 25) by a two-step “pH-adjusting method”,3 which allowed the incorporation of larger amounts of iron into SBA-15 as compared with the “conventional direct synthesis”. The influence of adjusted pH value (i.e., 2 ≤ pHadj ≤ 8) on the structural and textural properties of calcined Fe-SBA-15 as well as the coordination environments of iron was specifically


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Fig. 1 N2 adsorption/desorption isotherms at -196 oC (A) and DR UV-vis spectra (B) of calcined Fe-SBA-15 samples (Si/Fegel = 25)

investigated by low-angle XRD and N2 physisorption (Fig. 1 A) and DR UV-vis spectroscopy (Fig. 1 B), respectively.

It was found that the progressive increase of the pHadj value results in two different effects: (i) the decline of both mesopore ordering and textural quality of Fe-SBA-15, obviously at pHadj = 8 and more importantly (ii) the monotonic increase in the relative content of isolated framework iron species (bands at ~250 nm) at the expense of extraframework iron oligomers (bands at ~320 nm) and highly dispersed iron oxide clusters (bands at ~500 nm).

Fe-SBA-15 prepared at pHadj = 8 was preliminary tested in the hydrogen peroxide oxidation of Acid Red 1 (T = 50 oC and pH = 3) and the results indicated an outstanding catalytic activity (total oxidation in 20 min of reaction).


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References: 1. M. Hartmann, S. Kullmanna and H. Kellerb, J. Mater. Chem.,

2010, 20, 9002. 2. Y. Li, Z. Feng, Y. Lian, K. Sun, L. Zhang, G. Jia, Q. Yang and

C. Li, Microporous Mesoporous Mater., 2005, 84, 41. 3. S. Wu, Y. Han, Y.C. Zou, J.W. Song, L. Zhao, Y. Di, S.Z. Liu,

and F.S. Xiao, Chem. Mater., 2004, 16, 486.


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PEGylation of a mutant hemerythrin

for use in blood substitutes

Mariann-Kinga ARKOSI1, Augustin MOT1, Iulia LUPAN2,

Radu SILAGHI-DUMITRESCU1

1 Department of Chemistry and Chemical Engineering,

2 Department of Biology and Geology; ”Babes-Bolyai” University, 11 Arany Janos street, Cluj-

Napoca RO-400028, Romania; [email protected]

Hemerythrin (Hr) is an oxygen-carrier protein found

in marine invertebrates, which binds oxygen reversibly by the use of a non-heme diiron center. It has already been proposed as a very promising alternative raw material to hemoglobin-based blood substitutes due to its negligible redox reactivity toward oxidative and nitrosative stress agents. Strategies for conversion of Hr into an effective blood substitute would involve chemical modifications which improve its qualities, such as PEGylation of the protein surface, polymerization and copolymerization.

PEGylation should contribute to limit extravasation and antigenicity of an Hr-based blood substitute, because coating the protein with such units increases the apparent volume simultaneously with reducing immunogenicity. The first targets of the PEGylation experiments were the eleven lysine residues on the surface of each subunit of the Hr octamer. Size-exclusion chromatography revealed that the Hr octamer tended to dissociate after reaching a certain degree of PEGylation, presumably due to steric restrictions


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within the PEGylated octamer. Site-directed mutagenesis allowed us to obtain the K92C mutant in which one of the lysines on the surface was converted into a cysteine residue. UV–Vis absorption spectra show that this modification did not affect the diiron site. This newly-inserted cysteine has now allowed a single PEG unit to be attached per monomer.

This work aims to present the steps that were taken in optimization of the reaction with the sulfhydryl-reactive PEGylation reagent. Besides, the results of oxygen affinity and autooxidation rate measurements are described here; these are key parameters for dioxygen reactivity and accordingly are indispensable for evaluation of the effectiveness of the derivatization for use in blood substitutes. Experimental data suggest that the half life of the PEGylated K92C Hr oxy form (capable of oxygen delivery) is seriously diminished, which is indicative of a necessity to counteract this aspect with further chemical modifications (e.g. polymerization with bovine serum albumin). References: 1. Mot, A. C.; Roman, A.; Lupan, I.; Kurtz, Jr. D. M.; Silaghi-Dumitrescu, R.; Towards the development of hemerythrin-based blood substitutes, The Protein Journal, 2010, 29(6): 387-93. 2. Fischer-Fodor, E.; Mot, A.; Deac, F.; Arkosi, M.; Silaghi-Dumitrescu, R.; Towards hemerythrin-based blood substitutes: comparative performance to hemoglobin on human leukocytes and umbilical vein endothelial cells, Journal of Biosciences, s2011 June, 36(2): 215-21. 3. Farmer, C. S.; Kurtz, Jr. D. M.; Phillips, R. S.; Ai, J.; Sanders-Loehr, J.; A Leucine Residue "Gates" Solvent but Not O2 access to the binding pocket of Phascolopsis gouldii Hemerythrin, The Journal of Biological Chemistry, 2000, 275: 17043-50.


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The influence of variety, vintage year and winery on antioxidant characteristics of some

Romanian white wines

Mihai Inceu 1, Anamaria Hosu 1, Claudia Cimpoiu 1

1 “Babeş-Bolyai” University, Faculty of Chemistry and Chemical Engineering, 11 Arany Janos, 400082 Cluj-Napoca, Romania, e-mail: [email protected]

Wine is a widely consumed beverage with thousands of years of tradition. The quality of a wine depends on its numerous constituents with the presence/absence and amount of a given chemical playing a considerable role [1]. The positive health effects of the consumption of wines are due to their phenolic constituents with significant antioxidant activity [2]. The production of white wines involves a great effort to avoid extensive contact with oxygen which might be deleterious in terse of color alteration (browning) and eventually determination of the overall quality and marketability [3]. One of the most important polyphenolic constituents in white wines, in terms of quantity, are the polyphenols and flavonoids.

The bioactive compounds in wine are responsible for the reduced risk of developing different diseases, especially blood related ones and even cancer, due to their high antioxidant activity.

In this study, we evaluated the influence of wine variety, vintage year and winery on the antioxidant activity and its correlation with polyphenolic content and flavonoid content. Sauvignon Blanc (SB), Feteasca Alba (FA), and


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Riesling (R) wines, produced in three different years by different Romanian wineries, were investigated in terms of antioxidant activity, total phenolic content (TPC) and total flavonoid content (TFC) by spectrophotometric methods. The antioxidant characteristics depend on the wine variety, vintage year and winery. As presented in the chart below, the wine with the lowest antioxidant activity is SB from “Oprisor” winery (year 2010) and the one with the highest antioxidant activity is FA from “Serve Ceptura”, also produced in 2010.

Acknowledgements This research is supported by CNCSIS-UEFISCDI, project number PNII-RU 203/2010 References 1. Silva, R.L.; Andrade, P.B.; Valentao, P. Seabra, R.M.; Trujillo, M.E.; Velazquez, E.; Food Chem. 2005, 89, 185-189. 2. Hosu, A.; Cimpoiu, C.; Miclaus, V.; Danciu, V.; Inceu, M.; Studia UBB Chemia, 2011, 4, 55-62. 3. Salacha, M.I.; Kallithraka, S.; Tzourou, I. Int. J. Food Sci. Tech. 2008, 43, 1073-1077.


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Hemoglobin-based copolymers with potential as blood substitutes: increased molecular

weight, reduced prooxidant reactivity

Scurtu F., Zolog O, Silaghi-Dumitrescu R.* Department of Chemistry and Chemical Engineering, “Babes,-Bolyai” University, 11 Arany Janos str., 400028 Cluj-Napoca, Romania; email: [email protected], Tel.: +40-264593833, Fax: +40-264-590818

Abstract

Hemoglobin (Hb) derivatization for blood substitute

purposes typically involves multi-step processes, often with

a redox reagent such as borohydride (when polymerizing

with glutaraldehyde) or periodate – which incurs

autooxidation and subsequent side-effects in biological

tests. Disuccinimidyl suberate (DSS) is a homobifunctional

N hydroxysuccinimide ester (NHS-ester) allowing for

protein crosslinking agent without toxic side-products and

forming peptide bonds with the lysine residues in one single

step. Here, we report that Hb polymers were obtained DSS,

making this the first report of a single-step polymerization

for blood substitutes. The increase in autooxidation rate


28

incurred by this polymerization is completely reversed

when BSA is co-polymerized with Hb. In fact, co-

polymerization of Hb with BSA appears to be beneficial for

alleviating prooxidant effects, regardless of the

polymerizing agent employed.

References: (Times New Roman 11 p.,Italic Justify, Bottom of page) 1. A. I. Alayash, Oxygen therapeutics: can we tame

haemoglobin?, Nat Rev Drug Discov 3 (2004) 152-159.

2. J. Y. Chen, M. Scerbo, and G. Kramer, A review of blood

substitutes: examining the history, clinical trial results, and

ethics of hemoglobin-based oxygen carriers., Clinics (Sao Paulo)

64 (2009) 803-813.

3. R. M. Winslow, MP4, a new nonvasoactive polyethylene

glycol-hemoglobin conjugate, Artif Organs 28 (2004) 800-806.

4. D. H. Doherty, M. P. Doyle, S. R. Curry, R. J. Vali, T. J.

Fattor, J. S. Olson, and D. D. Lemon, Rate of reaction with nitric

oxide determines the hypertensive effect of cell-free hemoglobin,

Nat Biotechnol 16 (1998) 672-676.


29

Anthocyanins from Cornelian Cherries (Cornus mas L.). Optimization of the

extraction methods

Ioana Orga1, Luminita-Camelia David1, Bianca-Elena Moldovan1,


[email protected] In the last decades the interest in the anthocyanin pigments has increased because of their possible utilization as natural food colorants and especially as antioxidant and anti- inflammatory agents. Cornelian Cherries are a good source of anthocyanins due to their content of polyphenol and their good stability by thermal processing. A systematic approach for optimizing the extraction of anthocyanins from Cornelian Cherries fruits was developed. Type of the acid, extraction temperature and time influence were investigated. A mixture of ethanol, hydrochloric acid (0.1% v:v) was found to be the best solvent system for Cornelian Cherries anthocyanins extraction. The highest total anthocyanins content (TAC) was obtained at an extraction time of 60 minutes and a temperature of 60°C. References: 1. Carmen Socaciu, Chemical and functional properties of food components series, University of Agricultural Science and Veterinaty Medicine, 2007. 2.G.E.Pantelidis, M. Vasilakakis, G.A. Manganaris, Gr. Diamantidis,Antioxidant capacity, phenol, anthocyanin and ascorbic acid contents in raspberries, blackberries, red currants, gooseberrie and Cornelian Cherries, Food Chemistry, 2006.


30

Maillard Reactions and Its Role in Cereal Products

Adriana Paucean1, Burak Ağuş2, Carmen Socaciu1, Ergun

Köse2, Neriman Bağdatlıoğlu2, Selman Kasım2

1 University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca Departement of Food Science and Technology, 64 Calea Floresti Street, Cluj-Napoca, ROMANIA. [email protected] 2 Celal Bayar Üniversitesi Mühendislik Fakültesi Gıda Mühendisliği Bölümü, Muradiye Manisa, TURKEY. [email protected] [email protected] Abstract

The non-enzymatic reactions that occur between the free amino groups of peptides or proteins and reducing sugars or lipid oxidation products are called "Maillard Reactions". These reactions are effected by the type and quantity of the components that take place in the reactions as well as heat, pH and water activity. Furfural, hydroxymethylfurfural, melanoidins, and acrylamide are the most known products of Maillard reactions. The products of maillard reactions are responsible for the specific taste of many food products such as bread, meat, beer, breakfast cereals and cakes but because of the carcinogenic, cytotoxic and genotoxic effects of the advanced reaction products, these reactions are not always desired to occur while processing the food. In this study, the importance and functions of maillard


31

reactions on bread, breakfast cereals and cakes will be reviewed. Key Words: Maillard Reaction, Cereal Products, Acrylamide

Figure 1

References:

1. A.K. Datta, 2008, Bread Baking, Agricultural and Food Engineering Department, IIT, Kharagpur 721 302, India

2. Yıldız O., 2010, Maillard Reactions and Importance of

Reaction Products in Foods, Giresun Universitesi, Şebinkarahisar Meslek Yüksekokulu, Gıda Teknolojisi Bölümü, Şebinkarahisar, Giresun

3. Tressl, R., Rewicki, D., 1999. Heat generated flavors and

precursors. In: Flavor Chemistry: Thirty Years of Progress, R.Teranishi, I. Hornstein, E.L. Wick (Eds.), Kluwer Academic/Plenum Publishers, New York, pp. 305-325.

4. Hodge, J.E., 1953 Chemistry of browning reactions in

model systems. Journal of Agriculture and Food Chemistry 1: 928-943.

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