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Enniatins (ENs), produced by Fusarium species are a group of mycotoxins with antimicrobial, insecticidal (GROVE & POPLE, 1980) and phytotoxic activities. PCR based assays were applied for detecting enniatin-producing strains of Fusarium avenaceum, F. poae and F. sporotrichioides isolated from wheat seeds originated of 30 geographic localities of Hungary. All F. sporotrichoides strains and except two of all F. poae strains gave positive signal to esysp1 and esysp2 primers as well as all F. avenaceum isolates were positive to esya1 and esya2 primers indicating the ability to produce ENs. This is a first report of the enniatin producing ability of Fusarium species associated to wheat in Hungary.

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Campylobacter jejuni and C. coli are among the most important causes of acute diarrhoea in humans throughout the world. Poultry meat is a major source of Campylobacter infections. Sensitive detection methods are necessary to identify contaminated samples. Detection of campylobacters by culturing is slow and tedious, whereas PCR technology offers the potential for rapid and sensitive detection, however, it may be inhibited when used directly for food or pre-enriched food samples. Different methods for sample and/or DNA preparation were studied to find an optimal combination for sensitive PCR detection of C. coli in enrichment broth. Buoyant density centrifugation (BDC) prior to cell lysis improved PCR detection of C. coli by 100-1000-fold. Preston enrichment broth spiked with 101-102 CFU ml-1 was detected positive after 18 h of enrichment. Specific flaA PCR detection of C. coli in enrichment broth following BDC and simple heat lysis of the cells can be conducted within two working days. This study is a part of the undergoing development of a rapid and sensitive molecular procedure for specific detection of C. coli in foods.

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Acta Alimentaria
Authors:
J. Krulj
,
N. Ćurčıć
,
A. Bočarov Stančıć
,
J. Kojıć
,
L. Pezo
,
L. Peıć Tukuljac
, and
M. Bodroža Solarov

spp. based on morphological attributes is not unusual ( Wanu et al., 2001 ). Therefore, most identification methodologies are now based on DNA detection by using polymerase chain reaction (PCR) methods. The ITS region is considered to be a universal and

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Acta Alimentaria
Authors:
A. Csikos
,
A. Hodzic
,
E. Pasic-Juhas
,
A. Javor
,
A. Hrković-Porobija
,
T. Goletic
,
G. Gulyas
, and
L. Czegledi

References A BDEL-RAHMAN , S.M. & A HMED , M.M.M. ( 2007 ): Rapid and sensitive identification of buffalo’s, cattle’s, and sheep’s milk using species-specific PCR and

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It is well established that the ingestion of cereal prolamins, such as gluten, causes the characteristic symptoms of celiac disease (CD) in people predisposed to it. DNA-based PCR method provides new ways to detect gluten in processed foodstuffs, such as bread. The aim of this work was to adapt a new primer pair combination and to initiate a carefully elaborated PCR methodology to experiment with DNA-based analysis. At first, the purity of cleaned DNA was verified using B49317 and A49855 chloroplast DNA primer pair. Then TR01/2 wheat specific PCR primer pair was used for checking the origin of the DNA, and P1/2 microsatellite (SSR) adapted primer pair for detecting allergen (gluten) specific residues. Method optimisation was achieved with cereal flour samples, then bread and dry pasta products from wheat were used, which were analysed as heat-treated samples with three primer pairs. The gluten specific primer pair was tested on cross-reactive cereals such as rye, barley, triticale and on some questionable cereals, such as oat, and pseudo-cereals, e.g. buck wheat and amaranth.

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The main goal of our work was to develop a rapid, simple, and economical DNA extraction method for food (especially for meat products) analysis. This extraction and purification procedure was based on the three-phase partitioning (TPP) method. The developed new DNA-TPP method and Wizard DNA Clean-Up System (Promega, USA) have been compared concerning extraction efficiency, purity and DNA suitability for amplification. The quality and quantity of the purified DNA solutions were controlled by spectrophotometer and the amplification efficiency by simple qualitative PCR. All of prepared DNA solutions were pure enough for the PCR and contained appropriate quantity of DNA. Thus, 118 bp length amplicons could have been obtained by the specific lectin-gene PCR in all cases. This method proved to be an alternative one to isolate DNA from meat samples simply and economically.

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B. cereus and B. thuringiensis strains have been associated with gastro-intestinal infections due to enterotoxins production. The possibility of differentiating between B. cereus and B. thuringiensis is a real need in preventing intoxication and in monitoring potentially contaminated foods. The use of DNA comparison provides clearer results than classical microbiological methods in distinguishing B. cereus from B. thuringiensis . The use of a Polymerase Chain Reaction (PCR) followed by Endonuclease Restriction (RE) made the distinction possible in spite of the huge similarity between the two closely related species.

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Nanopages
Authors:
Imrich Barák
,
Massimo Barbaro
,
Dušan Blaškovič
,
Annalisa Bonfiglio
,
Andrea Alessandrini
,
Denisa Mullerová
,
Paolo Facci
, and
Luigi Raffo

Number of pathogenic tick-borne bacteria cause diseases in humans and animals. Wide range of conventional methods as PCR, immuno-based detection, cultivation, reverse line blot or microscopy is available for identification of bacterial pathogens. Although, these methods are used often in laboratories, they do not allow simultaneous detection of wide spectrum of bacteria. DNA chips represent technology for fast, sensitive, relatively cheap and simultaneous detection of microorganisms in biological samples. We have developed the oligo-chip for detection of different tick-borne pathogens. This method is based on detection of fluorescent signal after hybridization reaction by using laser scanner. We are also working on preparation of electronic device for detection of specific contact of two single complementary strands of DNA. This method will allow simple detection without using the fluorescent probes and expensive laser scanner. For this purpose a novel solid-state sensor for detection of bio-molecular processes was developed. The device is compatible with a standard CMOS process, providing fully electronic readout and large-scale of integration of biosensors on a single chip. A model of the device was developed and simulated.

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Six strains (Bi11, Bi30, Bi36, Bi50, Bi52 and Bi55) isolated from bio-yoghurts and two strains (KD10 and KD11) derived from human faeces were identified by genus- and species specific polymerase chain reaction (PCR) with reference to the type strains of B. animalis subsp. lactis DSM 10140 and B. animalis subsp. animalis DSM 20104. The isolates were differentiated by using Bcu I ( Spe I), Xba I and Dra I endonucleases for subsequent pulsed field gel electrophoresis (PFGE) technique and by API 50 CHL tests.All the isolates tested were classified to B. animalis subsp. lactis species. The reliable identification as B. animalis subsp. lactis (by PCR with Bflact2/Bflact5 primers), however, required confirmation by a negative result of B. animalis subsp. animalis -specific PCR.Differentiation of the B. animalis subsp. lactis isolates with PFGE method enabled to distinguish KD11 strain with all the restriction enzymes applied, and Bi11 and Bi30 — exclusively with Dra I and Spe I enzymes, respectively. The biochemical tests, however, revealed that all the strains tested were characterised by a unique fermentation pattern. It was concluded that differentiation of the B. animalis subsp. lactis strains should be carried out on the basis of both genetic and phenotypic features.

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The Wizard Clean up System and a three-phase partitioning (TPP) method were used to purify genomic pork-DNA of various food samples for amplification. Quality of DNA purified by Wizard resin and partitioning was controlled by spectrophotometer and electrophoresis, respectively. A 108 bp fragment from the porcine growth hormone gene was applied, according to M EYER and co-workers (1994). Of all the samples prepared, amplicons were obtained by the pork- DNA specific PCR. Partitioning was found to be an efficient DNA purification step in preparation of PCR-grade DNA.

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