Analysis of possible biofilm formation from different Salmonella serovars isolated from animal food in in vitro conditions.

Cilj ovog istraživanja je bio ispitivanje sposobnosti formiranja biofilma kod serovarijeteta Salmonella izolovanih iz hrane za životinje, poreklom iz 18 mešaona stočne hrane na području Južnobačkog okruga. Izolati korišćeni u ispitivanju (n=100) izolovani su poreklom iz uzoraka hrane za životinje uzorkovanih tokom dve godine ispitivanja (period 2012-2014). Identifikacija izolata izvršena je na osnovu kulturelnih, biohemijskih i seroloških karakteristika na osnovu preporuka standarda SRPS EN ISO 6579:2008. Potvrda i serološka tipizacija izolata Salmonella izvedena je u Nacionalnoj referentnoj laboratoriji za Salmonella, Shigela, Vibrio cholerae i Yersinia enterocolitica, Instituta za javno zdravlje Srbije „Dr Milan Jovanović Batut“ u Beogradu. Kao kontrolni sojevi, u ispitivanju su korišćene referentne kulture S. Typhimurium ATCC 14028 i S. Enteritidis ATCC 13076. Kao supstrat za formiranje biofilma korišćene su površine od polistirena i nerđajućeg čelika. Sposobnost formiranja biofilma ispitana je primenom sledećih metoda: Congo red agar test, pelikula test, test na mikrotitracionim pločama upotrebom kristal violet boje, i skenirajuća elektronska mikroskopija (SEM). Sva ispitivanja izvedena su upotrebom dve hranljive podloge (tripton soja bujona i Luria Bertani bujona) pri temperaturi inkubacije od 20C i 37C. Iz hrane za životinje izolovani su sledeći serovarijeteti Salmonella: Tennessee (18%), Agona (9%), Montevideo (15%), Enteritidis (12%), Stanleyville (6%), Infantis (12%), Typhimurium (3%), Typhimurium monofazni (1%), Mbandaka (6%), Senftenberg (7%), Jerusalem (2%), Thompson (1%), Amsterdam (1%), Colindale (1%), Dahra (1%), Livingstone (1%). Kod četiri izolata nije ustanovljen serovarijetet (Salmonella enterica subspecies enterica (1,3,19:i:-)). Prema rezultatima Congo red agar testa, na temperaturi od 20C, 98% izolata Salmonella ekspresioniralo je jednu ili obe komponente matriksa biofilma i formiralo kolonije RDAR, PDAR i BDAR morfotipova...The aim of this research was the investigation into the biofilm-forming ability of Salmonella serovars isolated from animal feed samples originating from 18 feedproducing facilities located in South Bačka District. The isolates which were tested (n=100) were isolated from feed samples collected in a two-year period (from 2012 to 2014). The identification of the isolates was made based on the cultural, biochemical and serological characteristics, following the recommendations given in the SRPS EN ISO 6579:2008 standard. The conformation and serological typing of Salmonella isolates were done in the National Reference Laboratory for Salmonella, Shigela, Vibrio cholerae and Yersinia enterocolitica, at the Institute of Public Health of Serbia 'Dr Milan Jovanović Batut' in Belgrade. In this study reference cultures of S. Typhimurium ATCC 14028 and S. Enteritidis ATCC 13076 were used as the control strains. Surfaces made of polystyrene and of stainless steel were used as substrates for biofilm formation. The ability of Salmonella to form biofilm was tested with the following methods: Congo red agar test, pellicle test, microtiter plate assay with the use of crystal violet dye, and scanning electron microscopy (SEM). The whole investigation was carried out at two temperatures of incubation (20C and 37C). The following Salmonella serovars were isolated from animal feed: Tennessee (18%), Agona (9%), Montevideo (15%), Enteritidis (12%), Stanleyville (6%), Infantis (12%), Typhimurium (3%), Typhimurium monofazni (1%), Mbandaka (6%), Senftenberg (7%), Jerusalem (2%), Thompson (1%), Amsterdam (1%), Colindale (1%), Dahra (1%), Livingstone (1%). In four isolates serovars were not determined (Salmonella enterica subspecies enterica (1,3,19:i:-)). According to the results of Congo red agar test, when grown at 20C, 98% of the isolates expressed one or both components of the Salmonella biofilm matrix and formed colonies of various morphotypes (RDAR, PDAR and BDAR)..

Improving the economic performances of the beet-sugar industry

General trend of free trade at the regional level as well as in the direction of European Union has motivated sugar factories located in Serbia to invest into technologies that are more efficient in order to make their products more competitive in the markets of Europe. Until 2005, the project of energy efficiency improvement in Serbian sugar factories was conducted in Crvenka and Žabalj. Now, they have energy consumption around 1 MJ/kg beet, in contrast to the previous consumption of 1.2 up to 1.5 MJ/kg beet. Further improvements are possible but investments would be high. A result of measurements taken during 2006, after the sugar factory "Donji Srem" - Pećinci was reconstructed showed that a considerable saving has been achieved. The first set of measurements showed that the energy consumption was 1.01 MJ/kg beet, which was 20% higher than intended, but at the same time energy savings were about 30% lower with respect to the values before the reconstruction

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

Metagonimus yokogawai: A new parasitic trematoda species in ichtyoparasitofauna of the Serbia

During the study of fish parasites in the Serbian section of the Danube River in 2003, a new Trematoda species for ichthyofauna of Serbia has been detected. It is, at the same time, the first finding of larvae of Metagonimus yokogawai in Serbia, as adult forms have been observed from mallard Anas platyrhynchus (L.), previously. Metacercariae of M. yokogawai have been identified on the scales of chub Leuciscus cephalus (L.), barbel Barbus barbus (L.), bleak Alburnus alburnus (L.), pikeperch Sander lucioperca (L.) and rudd Scardinius erythrophthalmus (L.) in the Serbian part of Danube River. The particular risk, beside the possible negative influence of spreading on fish and other host populations (some aquatic snails, fish-eating birds and some mammals), is the potential spreading of the parasitic disease in humans - Metagonimosis.Tokom istraživanja parazita riba srpskog dela Dunava (2003) nađena je nova vrsta Trematoda za ihtioparazitofaunu Srbije. Ovaj nalaz je istovremeno i prvi nalaz larvi (metacerkarija) metilja Metagonimus yokogawai (Katsurada, 1912) s obzirom da su odrasle jedinke ovog parazita nađene prethodno kod divljih pataka Anas platyrhynchus (L). Metacerkarije M. yokogawai pronađene su na krljuštima klena Leuciscus cephalus (L.), mrene Barbus barbus (L.) uklije Alburnus alburnus (L.), smuđa Sander lucioperca (L.) i crvenoperke Scardinius erythrophthalmus (L). Posebna opasnost, pored širenja infekcije metiljem M. yokogawai i negativnog uticaja na populaciju riba i ostalih prelaznih domaćina (neki vodeni puževi, ribojedne vrste ptica i neki sisari), jeste i pojava metagonimioze kod ribojednih sisara, među kojima je i čovek.nul

Optimization of cultivation medium for the production of antibacterial agents

Optimization of the cultivation medium for production of antibiotic effective against pathogenic bacteria Staphylococcus aureus using strain of Streptomyces spp. isolated from the environment represents the aim of this study. After the biosynthesis, the medium was analyzed by determining residual sugar and nitrogen, and the antibiotic activity was determined using diffusion-disc method. Experiments were carried out in accordance with the Box-Behnken design, with three factors varied on three levels (glucose: 10.0, 30.0 and 50.0 g/L; soybean meal: 5.0, 15.0 and 25.0 g/L; phosphates: 0.5, 1.0 and 1.5 g/L) and for the optimization of selected parameters Response Surface Methodology was used. The obtained model with the desirability function of 0.985 estimates that the lowest amounts of residual sugar (0.89 g/L) and nitrogen (0.24 g/L) and the largest possible inhibition zone diameter (21.88 mm) that with its antibiotic activity against S. aureus creates the medium containing 10.0 g/L glucose, 5.0 g/L soybean meal and 1.04 g/L phosphates

Fumonisins and co-occurring mycotoxins in north Serbian corn

The presence of fumonisin has not been regulated in the legislation of the Republic of Serbia. Therefore, the data on contamination of cereals, especially corn, which is highly susceptible to contamination by this toxin, are not sufficient. This paper presents the results of testing the corn samples collected in the autumn 2009 on the territory of Bačka. Samples were analyzed for the contents of fumonisins and it was determined whether there is a correlation between the moisture content, total number and class of fungi, as well as the content of aflatoxin, ochratoxin and zearalenone. Using enzymatic immunoaffinity method it was discovered that the highest percentage of samples were contaminated with fumonisins, which was probably due to the presence of Fusarium molds as the most abundant ones. The positive samples contained fumonisin in the concentrations from 0.030 to 1.52 mg kg−1. The influence of the climate and moisture content of grain on fungal contamination and mycotoxin production was analyzed in order to investigate the predictability of the presence of mycotoxins

Elisa and HPLC analyses of deoxynivalenol in maize and wheat

Deoxynivalenol (DON) is a part of the family of mycotoxins called trichothecenes which are produced by a number of different Fusarium mold species. The presence of DON in 25 wheat and 25 maize samples was examined by Enzyme Linked Immunosorbent Assay (ELISA) and High Performance Liquid Chromatography (HPLC) methods. The presence of DON was detected and determined in 5 (20%) maize and 6 (25%) wheat samples by both of the methods. Correlation between ELISA and HPLC results was established, with the correlation coefficients (r) of 0.9691 and 0.9735 for wheat and maize samples, respectively. The results obtained by ELISA method were significantly higher than those obtained by HPLC method. This fact can be explained by the presence of conjugated or masked mycotoxins in the samples, especially DON-3-glucoside (DON-3-Glc), which could not be determined by HPLC method due to the lack of external standards. Contrary to this, being insufficiently selective towards masked DON, ELISA method measures total DON content of a sample. According to the obtained results, ELISA can be used as a reliable screening method, but the confirmation of positive results must be done by HPLC method

Sagorevanje otpadnog termobaričnog eksploziva pod kontrolisanim uslovima kao izvor energije

Thermobaric explosive mixtures are recently widely studied due to their specific energetic effects, especially regarding thermal output during the post-detonation combustion phase. Most of these mixtures contain as a very important component some metal powder fuel, which burns in contact with atmosphere oxygen or the oxidant component of the mixture after the initiation. This combustion process releases a large amount of thermal energy, which is recognized as a potential source of other types of energy if it were released and further transformed under controlled conditions. In this research, the possibility of controlled combustion of waste thermobaric explosives as a source of energy was considered. Thermobaric compositions containing aluminium, magnesium and boron powder were analysed. EXPLO5 software was used to calculate parameters of their isochoric and adiabatic combustion, to predict the potential thermal output of these mixtures. The selected compositions were experimentally examined in small samples by the method of calorimetry to determine their energetic potential during combustion in atmosphere of inert gas in a calorimetric bomb. The obtained results encourage further research into the possible applications of this thermal energy, which can be released not only in the reaction of a destructive explosion, but also by combustion under controlled conditions, as a quaternary recycling of waste explosives - a potential source of heat and electric energy.Termobarične eksplozivne smeše su u poslednje vreme dosta proučavane zbog specifičnih energetskih efekata, posebno u pogledu toplotnog dejstva tokom faze post-detonacionog sagorevanja. Većina ovih smeša sadrži kao veoma važnu gorivnu komponentu neki metalni prah koji nakon iniciranja sagoreva u kontaktu sa atmosferskim kiseonikom ili oksidatorskom komponentom smeše. Ovaj proces sagorevanja oslobađa veliku količinu toplotne energije, koja je prepoznata kao potencijalni izvor drugih vidova energij ukoliko bi se oslobađala i dalje transformisala pod kontrolisanim uslovima. U ovom istraživanju razmotrena je mogućnost kontrolisanog sagorevanja otpadnog termobaričnog eksploziva kao izvora energije. Analizirane su termobarične smeše koje sadrže prah aluminijuma, magnezijuma i bora. Za izračunavanje parametara njihovog izohorskog i adijabatskog sagorevanja korišćen je softver EXPLO5, za predviđanje potencijalnog toplotnog efekta ovih smeša. Odabrani sastavi su eksperimentalno ispitani metodom kalorimetrije na malim uzorcima kako bi se utvrdio njihov energetski potencijal pri sagorevanju u atmosferi inertnog gasa u kalorimetrijskoj bombi. Dobijeni rezultati podstiču dalje istraživanje mogućih primena ove toplotne energije koja se može osloboditi ne samo u reakciji destruktivne eksplozije, već i kroy sagorevanje u kontrolisanim uslovima, kao kvaternernu reciklažu otpadnih eksploziva - potencijalni izvor toplotne odnosno električne energije

Optical emission measurement of plasma generated by infrared laser beam with Cu target

A study of visible (VIS) optical emission of Cu-plasma, induced by infrared (IR) Transversely Excited Atmospheric (TEA) CO2 laser, was carried out. Irradiation of the Cu-target with laser fluence of 8.2 J/cm2 at low air pressure resulted in the appearance of intensive plasma over the target. The type, number and intensity of the emission Cu-spectral lines strongly depend on the observing plasma location with respect to the target surface. “Primary” plasma gives the largest number of spectral lines. Also, in contrary to other plasma locations, some ionic lines were detected from this region. “Secondary” plasma, as a rule, gives the atomic lines. This region of plasma is very favourable for possible analytical applications (e.g. quantitative analysis)

Comparison between Organic and Conventional Spelt and Wheatgrass juice

This work is aimed to compare antioxidant and scavenger properties of conventionally and organically produced speltgrass. Moreover, the antioxidant status of spelt was compared with wheatgrass. Three spelt varieties were analyzed:Nirvana, Ebners–Rotkorn variety and Eco-10. Antioxidant enzymes, superoxide-dismutase and guiacol-peroxidase, were determined as well as ferric reducing antioxidant power and DPPH-antiradical power. Total soluble proteins and total phenols were determined and also lipid peroxidation as a parameter of oxidative stress. The organically produced spelt was exposed to the higher levels of oxidative stress than conventionally produced spelt, and also DPPH antiradical power was induced by conventional production, which is also demonstrated using the relative antioxidant capacity index. The best antioxidant properties, better than wheat, showed organically produced spelt genotype Ebners–Rotkorn which is determined by the highest phenol content, superoxide-dismutase activity, DPPH antiradical power and ferric reduced antioxidant power and consequently with the lowest lipid peroxidation intensity