Primena bakar-selektivne elektrode tipa prekrivena žica za određivanje bakra(II) potenciometrijskom titracijom sa etilendiaminom u vodenim i nevodenim rastvorima

In this work, potentiometric titrations of the solution of the Cu(II) ione have been executed with ethylenediamine as complexing agent and the copper selective electrode coated wire type/SCE indicator system in aqueous and nonaqueous solvents. Because of the difficult conditions of the forma­tion of the Cu (II) ethylenediamine complex, due to the presence of parallel reactions influencing the position of the basic balance of the formation of the complex, this study discusses and deduces the equations for the calculation of the constant of the formation of the complex as well as the equations for the calculation of the free ethylenediamine. In all the cases a pronounced extreme of the curve of titration has been remarked in the final phase of the titration, whatever diluent was used. Similar results have been obtained using solvents such as: water, alcohol (methanol, ethanol, buthanol), which was expected having in mind the chemical resemblance of these compounds (polar mollecules), while a sharper extreme was obtained in N,N-dymethylformamide, which was expected as well because of the similar basic characteristics with ethylenediamine. The results obtained by this study show the exceptional advantage of ethylenediamine as complexing agent and also the possibility of the application of the copper selective electrode coated wire type/SCE indicating system for the determina­tion of Cu(II) in aqueous and non-aqueous solvents and for the determination of the constants of the determination of the formation of the ethylenediamine complex. .Formiranje kompleksa Cu(II) sa etilendiaminom otežano je postojanjem paralelnih ravnoteža sa reaktantima, koji reagujući sa ligandom, etilendiaminom, ili Cu(II) jonom utiču na položaj osnovne ravnoteže građenja kompleksa. Polazeći od konstatacije da svojstva etilendiaminada gradi stabilne komplekse sa mnogobrojnim jonima u analitičkoj hemiji nisu dovoljno iskorišćena, u ovome radu izvršena je analiza mogućih efekata na položaj ravnoteže građenja kompleksa kao i izvođenje jednačina za ukupnu konstantu obrazovanja B2 i za izračunavanje koncentracije slobodnog etilendiamina. U radu su izvršena potenciometrijska ispitivanja rastvora Cu(II) jona sa etilendiaminom kao kompleksirajućim agensom uz bakar-selektivna elektroda/zasićena kalomelova elektroda (ZKE) indikatorski sistem u vodenim i nevodenim rastvorima. Dobijeni rezultati pokazali su izuzetnu vrednost etilendiamina kao kompleksirajućeg agensa u poređenju sa drugim, konvencionalnim kompleksirajućima agensima, a takođe i mogućnost primene bakar-selektivna elektroda/ZKE indikatorskog sistema za određivanje konstante obrazovanja Cu(en)22+ kompleksa.

The application of sheet filters in treatment of fruit brandy after cold stabilization

Considering the common use of sheet filtration for clarification of fruit brandies, the aim of this study was to evaluate the influence of its application on the stability and composition of volatile compounds of apricot brandy after cold stabilisation. Cold stabilisation treatment involved holding of the brandy at -1°C during 24 hours. Five depth filter sheets with the nominal retention rate of 0.3 μm, 0.5-0.7 μm, 0.7-1.0 μm, 1.0-2.0 μm and 2.5-4.0 μm, were tested in the study. It was shown that all assessed filter sheets were efficient in removing chill haze by significantly reducing the content of fatty acid esters (primarily ethyl palmitate and ethyl laurate). Other volatile and aromatic compounds were not significantly influenced by the applied treatments. However, the filter sheets with higher nominal retention rate (> 0.7 μm), had a smaller impact on the sensory characteristics of the apricot brandy. The re-exposure to lower temperatures did not lead to chill haze formation in any sample obtained after sheet filtration. [Projekat Ministarstva nauke Republike Srbije, br. TR-31002

First Report of Leek yellow stripe virus in Leek in Serbia

Leek yellow stripe virus (LYSV), one of the most important and widespread viruses of leek and garlic worldwide, is endemic in various countries of the Mediterranean basin (Katis et al. 2012). During an October 2013 survey for the presence of Allium viruses in Serbia, commercially grown leek (Allium porrum) plants with virus-like symptoms were observed in Padinska Skela (City of Belgrade District). Initially, the leaf symptoms included irregular chlorotic to light yellow dashes, particularly on the bases of leaves. The lesions later enlarged and coalesced, resulting in large, yellow stripes and the infected leaves turned yellow and flaccid, followed by die-back. Disease incidence in the leek field was estimated at 20%. A total of 15 symptomatic plants were sampled and tested by double-antibody sandwich (DAS)-ELISA test using commercial polyclonal antisera (Bioreba AG, Reinach, Switzerland) for the most important Allium viruses: LYSV, Garlic common latent virus, Onion yellow dwarf virus, and Iris yellow spot virus (Pappu et al. 2005, Katis et al. 2012). Commercial positive and negative controls and extracts from healthy leek leaves were included in each ELISA. All 15 tested leek samples were positive for LYSV and negative for the rest of tested viruses. Five carborundum-dusted plants of each Chenopodium quinoa and A. porrum ‘Varna’ were mechanically inoculated with sap prepared from ELISA-positive sample (277-13) using 0.01 M phosphate buffer (pH 7). Chlorotic local lesions on C. quinoa and streak mosaic on A. porrum ‘Varna’ were observed 5 and 16 days postinoculation, respectively, on all inoculated plants. Serological results were verified with reverse transcription (RT)-PCR. Total RNAs from all naturally and mechanically infected leek plants were extracted using the RNeasy Plant Mini Kit (Qiagen, Hilden, Germany). RT-PCR was performed using One-Step RT-PCR Kit (Qiagen) and specific primer pair 1LYSV and 2LYSV (Fajardo et al. 2001). An approximately 1000-bp fragment corresponding to the part of nuclear inclusion B (NIb) and coat protein (CP) coding region was obtained from all 20 naturally and mechanically infected leek plants, while no amplicon was recorded in the healthy and water controls. RT-PCR product obtained from one selected isolate (277-13) was purified using QIAquick PCR Purification Kit (Qiagen), sequenced directly in both directions using the same primers as for amplification, and submitted to the GenBank (Accession No. KR075504). Sequence analysis, conducted by MEGA5 software (Tamura et al. 2011), revealed that the leek isolate from Serbia showed the highest nucleotide identity of 94.8% (94.6% amino acid identity) with the sequence of LYSV isolate from leek (X89711). To our knowledge, this is the first report of natural infection of leek with LYSV in Serbia. Leek is an important and traditionally grown vegetable crop in Serbia and the presence of LYSV could cause considerable damage and severe yield losses, resulting in significant economic impact on leek production

Biosynthesis of xanthan gum on wastewater from confectionary industry

Xanthan gum is one of the major commercial biopolymers employed in many industrial processes owing to its unique physical properties such as a high degree of pseudoplasticity and high viscosity even at low concentrations. Commercially available xanthan gum is relatively expensive due to glucose or sucrose being used as the sole carbon source for its production and cost reduction could be achieved by using less expensive substrates, such as food industrial wastewaters. Effluents from the confectionery industry, because of its high organic content, are significant environmental pollutants and before their release into environment it is necessary to purify them. The present study examines xanthan production by Xanthomonas campestris under aerobic conditions on wastewaters from five different factories of the confectionery industry. Xanthan yield was obtained as a quantitative characteristic of the process and was in the range between 4.28 g/L and 10.03 g/L and its quality is determined by following rheological characteristics of obtained cultivation media. The results obtained in this study indicate that wastewater from confectionary industry can be used as the basis of media for the production of this highly valuable product

First Report of Tomato spotted wilt virus on Chrysanthemum in Serbia

In July 2011, greenhouse-grown chrysanthemum hybrid plants (Chrysanthemum × morifolium) with symptoms resembling those associated with tospoviruses were observed in the Kupusina locality (West Bačka District, Serbia). Disease incidence was estimated at 40%. Symptomatic plants with chlorotic ring spots and line patterns were sampled and tested by double antibody sandwich (DAS)-ELISA using polyclonal antisera (Bioreba AG, Reinach, Switzerland) against the two of the most devastating tospoviruses in the greenhouse floriculture industry: Tomato spotted wilt virus (TSWV) and Impatiens necrotic spot virus (INSV) (2). Commercial positive and negative controls and extracts from healthy chrysanthemum tissue were included in each ELISA. TSWV was detected serologically in 16 of 20 chrysanthemum samples and all tested samples were negative for INSV. The virus was mechanically transmitted from ELISA-positive chrysanthemum samples to five plants each of both Petunia × hybrida and Nicotiana tabacum ‘Samsun’ using chilled 0.01 M phosphate buffer (pH 7) containing 0.1% sodium sulfite. Inoculated plants produced local necrotic spots and systemic chlorotic/necrotic concentric rings, consistent with symptoms caused by TSWV (1). The presence of TSWV in ELISA-positive chrysanthemum plants and N. tabacum‘Samsun’ was further confirmed by conventional reverse transcription (RT)-PCR. Total RNAs were extracted with an RNeasy Plant Mini Kit (Qiagen, Hilden, Germany). RT-PCR was performed with the One-Step RT-PCR Kit (Qiagen) using primers TSWVCP-f/TSWVCP-r specific to the nucleocapsid protein (N) gene (4). A Serbian isolate of TSWV from tobacco (GenBank Accession No. GQ373173) and RNA extracted from a healthy chrysanthemum plant were used as positive and negative controls, respectively. An amplicon of the correct predicted size (738-bp) was obtained from each of the plants assayed, and that derived from chrysanthemum isolate 529-11 was purified (QIAqick PCR Purification Kit, Qiagen) and sequenced (JQ692106). Sequence analysis of the partial N gene, conducted with MEGA5 software, revealed the highest nucleotide identity of 99.6% (99% amino acid identity) with 12 TSWV isolates deposited in GenBank originating from different hosts from Italy (HQ830186-87, DQ431237-38, DQ398945), Montenegro (GU355939-40, GU339506, GU339508), France (FR693055-56), and the Czech Republic (AJ296599). The consensus maximum parsimony tree obtained on a 705-bp partial N gene sequence of TSWV isolates available in GenBank revealed that Serbian TSWV isolate 529-11 from chrysanthemum was clustered in the European subpopulation 2, while the Serbian isolates from tomato (GU369723) and tobacco (GQ373172-73 and GQ355467) were clustered in the European subpopulation 1 denoted previously (3). The distribution of TSWV in commercial chrysanthemum crops is wide (2). To our knowledge, this is the first report of TSWV infecting chrysanthemum in Serbia. Since chrysanthemum popularity and returns have been rising rapidly, the presence of TSWV may significantly reduce quality of crops in Serbia. References: (1) Anonymous. OEPP/EPPO Bull. 34:271, 2004. (2) Daughtrey et al. Plant Dis. 81:1220, 1997. (3) I. Stanković et al. Acta Virol. 55:337, 2011. (4) A. Vučurović et al. Eur. J. Plant Pathol. 133:935, 2012. </jats:p

Selection of antagonists for biocontrol of xanthomonas euvesicatoria

Xanthomonas euvesicatoria is a worldwide causer of pepper bacterial spot, a bacterial plant disease responsible for massive losses of fresh pepper fruits. Considering the current problems in management of bacterial plant diseases, biological control using antagonistic microbial strains with high potential for plant pathogens suppression emerges as a possible solution. The aim of this study was to select suitable antagonists for suppression of X. euvesicatoria among the bacteria, yeast and fungi from the genera Pseudomonas, Lactobacillus, Saccharomyces and Trichoderma, based on in vitro antimicrobial activity testing using the diffusion disc method. The results of this study have revealed that cultivation broth samples of the antagonists Lactobacillus MK3 and Trichoderma reseii QM 9414, as well as supernatant samples of the antagonist Pseudomonas aeruginosa I128, have showed significant potential to be applied in biological control of X. euvesicatoria. Further research would be required to formulate suitable cultivation medium and optimize bioprocess conditions for production of the proposed pepper bacterial spot biocontrol agents

Thermo-Acid pretreatment of starch based kitchen waste for ethanol production

Recently, research on the alcoholic fermentation of kitchen waste has been accelerating for both ecological and economical reasons, primarily for ethanol use as renewable biofuel. Present work deals with the fermentative production of ethanol from different starch based kitchen waste. Kitchen waste from local students restaurant was separated by basic component as: peas, green beans, beans, rice, potato, wheat bread and corn. Thermo-acidic pretreatment of these raw materials was conducted by the addition of HCl up to pH of 1, and by autoclaving at 120&nbsp;oC for 30 min. From the experimental result, maximum ethanol yield was obtained from wheat bread (0.11 g/g). The highest ethanol yield per starch of 0.36 g/g, which equals to 64% of the theoretical value, was obtained for peas. From the overall analysis, the examined thermo-acid pretreatment was the most efficient for hydrolysis of wheat bread, while it was least efficient for green beans. In order to enhance the efficiency of conversion of starch from kitchen waste into ethanol, pH lower than 1 is highly recommended. The results demonstrated the potential of different food waste as a promising biomass resource for the production of ethanol

First Report of Cucumber mosaic virus Infecting Peperomia tuisana in Serbia

Peperomia tuisana C.DC. ex Pittier (family Piperaceae) is an attractive succulent grown as an ornamental. Despite its tropical origins, it can be successfully grown indoors in any climate. In March 2012, three samples of P. tuisana showing virus-like symptoms were collected from a commercial greenhouse in Zemun (District of Belgrade, Serbia) in which estimated disease incidence was 80%. Infected plants showed symptoms including necrotic ringspots and line patterns that enlarged and caused necrosis of leaves. A serious leaf drop led to growth reduction and even death of the plant. Leaves from three symptomatic P. tuisana plants were sampled and analyzed by double-antibody sandwich (DAS)-ELISA using commercial diagnostic kits (Bioreba AG, Reinach, Switzerland) against the most common viral pathogens of ornamentals: Cucumber mosaic virus (CMV), Tomato spotted wilt virus (TSWV), and Impatiens necrotic spot virus (INSV) (1,2). Commercial positive and negative controls were included in each ELISA. Serological analyses showed that all plants were positive for CMV and negative for TSWV and INSV. The ELISA-positive sample (isolate 1-12) was mechanically inoculated onto five plants each of three test species as well as of healthy young P. tuisana using 0.01 M phosphate buffer (pH 7). Chlorotic local lesions on Chenopodium quinoa and severe mosaic and leaf malformations were observed on all inoculated Nicotiana tabacum ‘Samsun’ and N. glutinosa. Also, the virus was successfully mechanically transmitted to P. tuisana that reacted with symptoms identical to those observed on the original host plants. All mechanically inoculated plants were positive for CMV in DAS-ELISA. For further confirmation of CMV infection, reverse transcription (RT)-PCR was performed on extracts made from symptomatic P. tuisana, N. tabacum ‘Samsun,’ and N. glutinosa leaf materials. Total RNAs were extracted with the RNeasy Plant Mini Kit (Qiagen, Hilden, Germany) and RT-PCR was carried out using One-Step RT-PCR Kit (Qiagen). A CMV-specific primer pair, CMVCPfwd and CMVCPrev (3), which amplifies an 871-bp fragment of the entire coat protein (CP) gene and part of 3′- and 5′-UTRs, were used for both amplification and sequencing. Total RNAs obtained from the Serbian CMV isolate (HM065510) and healthy P. tuisana were used as positive and negative controls, respectively. A product of the correct predicted size was obtained in all naturally and mechanically infected plants, as well as positive control. No amplicon was recorded in the healthy control. The amplified product derived from isolate 1-12 was purified (QIAquick PCR Purification Kit, Qiagen), directly sequenced in both directions, deposited in GenBank (KC505441), and analyzed by MEGA5 software (4). Sequence comparison of the complete CP gene (657 nt) revealed that the Serbian isolate 1-12 shared the highest nucleotide identity of 99.1% (99.5% amino acid identity) with the Japanese isolate (AB006813). To our knowledge, this is the first report on the occurrence of CMV in P. tuisana in Serbia. This is also an important discovery since P. tuisana is commonly grown together with other ornamental hosts of CMV, and thus could represent a serious threat for future expansion of CMV in the greenhouse floriculture industry in Serbia

Production of ethanol from Kantata wheat variety

Processing parameters of Kantata wheat variety indicate that it is not suitable for bread making. Therefore, an investigation was carried out to evaluate the suitability of the variety for ethanol production. Wheat was cultivated at the following sites: Kovin, Zrenjanin, Pančevo and Vrbas. Ethanol yields depend on the location on which the samples were grown and on the temperature during thermal and enzymatic preparation of flour samples. Wheat sample cultivated on the Vrbas site gave the highest ethanol yield

Thermo-acid pretreatment of starch based kitchen waste for ethanol production

Recently, research on the alcoholic fermentation of kitchen waste has been accelerating for both ecological and economical reasons, primarily for ethanol use as renewable biofuel. Present work deals with the fermentative production of ethanol from different starch based kitchen waste. Kitchen waste from local students restaurant was separated by basic component as: peas, green beans, beans, rice, potato, wheat bread and corn. Thermo-acidic pretreatment of these raw materials was conducted by the addition of HCl up to pH of 1, and by autoclaving at 120oC for 30 min. From the experimental result, maximum ethanol yield was obtained from wheat bread (0.11 g/g). The highest ethanol yield per starch of 0.36 g/g, which equals to 64% of the theoretical value, was obtained for peas. From the overall analysis, the examined thermo-acid pretreatment was the most efficient for hydrolysis of wheat bread, while it was least efficient for green beans. In order to enhance the efficiency of conversion of starch from kitchen waste into ethanol, pH lower than 1 is highly recommended. The results demonstrated the potential of different food waste as a promising biomass resource for the production of ethanol