Five wild plant species belonging to different families (Chenopodium album, Plantago major, Elytrigia elongata, Filipendula ulmaria and Nigella sativa) widely spread in Russian Federation and the former USSR were eval...Five wild plant species belonging to different families (Chenopodium album, Plantago major, Elytrigia elongata, Filipendula ulmaria and Nigella sativa) widely spread in Russian Federation and the former USSR were evaluated for their ability to inhibit growth of two important human food-borne pathogens (Escherichia coli O157:H7 and Listeria monocytogenes strain EGD-e) and eight plant pathogens (Alternaria alternata, Alternaria tenuissima, Bipolaris sorokiniana, Stagonospora nodorum, Fusarium solani, Fusarium oxysporum, Fusarium culmorum and Phytophtora infestans). To isolate biologically active compounds from seeds, a step-wise procedure including extraction with hexane, ethyl acetate, ethanol, and 10% acetic acid followed by reversed-phase HPLC was developed. Using disc-diffusion assay, the highest activity against E. coli O157:H7 was observed with extracts from F. ulmaria (hexane and ethyl acetate extracts and the unbound RP-HPLC fraction) and P. major (ethyl acetate extract and the unbound RP-HPLC fraction);E. elongate (the unbound RP-HPLC fraction) was less active. The extracts from P. major and E. elongate (the unbound RP-HPLC fractions) were equally highly active against L. monocytogenes, while those of F. ulmaria (the unbound RP-HPLC fraction) and N. sativa (hexane and ethyl acetate extracts) were less active against this pathogen. The dynamics of L. monocytogenes EGD-е and E. coli O157:H7 growth in the presence of two most potent extracts (RP-HPLC-unbound fractions of P. major and E. elongate and the hexane extract of F. ulmaria) was studied.展开更多
Next generation sequencing is a powerful technology whose application in sequencing entire RNA populations (RNA-Seq) of food-borne pathogens will provide valuable insights. A problem unique to prokaryotic RNA-Seq is r...Next generation sequencing is a powerful technology whose application in sequencing entire RNA populations (RNA-Seq) of food-borne pathogens will provide valuable insights. A problem unique to prokaryotic RNA-Seq is removal of ribosomal RNA. Unlike eukaryotic messenger RNA (mRNA), bacterial mRNA species are devoid of polyadenylation at the 3’-end and thus the approach of affinity enrichment of mRNA using oligo-dT probes is not an option. Among several approaches to enriching mRNA molecules, removal of ribosomal RNA (rRNA) by subtractive hybridization has been widely used. This approach is a single-step procedure for which several rRNA-depletion kits are commercially available. We evaluated three commercially available rRNA-depletion kits to determine their respective efficiencies of rRNA removal from Salmonella enterica serovar Typhimurium strain SL1344. The three protocols achieved varying degrees of rRNA depletion and resulted in 8 to 1000-fold enrichment of mRNA. rRNA removal probes from two of the three kits were unable to titrate out 23S rRNA species while removal of 16S rRNA was less efficient. The Ribo-Zero kit was most efficient in eliminating 16S, 23S and 5S ribosomal RNA species from the transcriptome of S. enterica serovar Typhimurium strain SL1344.展开更多
This study investigated the spread of foodborne pathogens: Listeria monocytogenes, Es-cherichia coli O157:H7, Staphylococcus aureus and Salmonella in chicken sausage samples collected from retail markets in Greece and...This study investigated the spread of foodborne pathogens: Listeria monocytogenes, Es-cherichia coli O157:H7, Staphylococcus aureus and Salmonella in chicken sausage samples collected from retail markets in Greece and Egypt during 2006 and from Egypt through 2010. Other microbiological parameters;total viable count (TVC), lactic acid bacteria (LAB), pseudomonads (PS), staphylococci (STAPH), Brochothrix thermosphacta (BT), Enterobacteriaceae (EN), Escherichia coli (EC), yeasts and moulds (Y&M) were also counted. Egyptian chicken sausage samples were found to harbor L. mono- cytogenes, Staph. aureus and E. coli O157:H7;with frequencies equivalent to 24%, 60% and 26% of the total samples during 2006 and 37.87%, 64.44% and 41.11% of the total samples during 2010, respectively, while Greek samples were entirely free of theses pathogens. Enrichment techniques indicated the absence of Salmonella from both Greek and Egyptian samples. The obtained results may mobilize food producers and handlers in developing countries to take the due measures reducing food-borne pathogen risks and spoilage flora alongside the poultry chain.展开更多
文摘Five wild plant species belonging to different families (Chenopodium album, Plantago major, Elytrigia elongata, Filipendula ulmaria and Nigella sativa) widely spread in Russian Federation and the former USSR were evaluated for their ability to inhibit growth of two important human food-borne pathogens (Escherichia coli O157:H7 and Listeria monocytogenes strain EGD-e) and eight plant pathogens (Alternaria alternata, Alternaria tenuissima, Bipolaris sorokiniana, Stagonospora nodorum, Fusarium solani, Fusarium oxysporum, Fusarium culmorum and Phytophtora infestans). To isolate biologically active compounds from seeds, a step-wise procedure including extraction with hexane, ethyl acetate, ethanol, and 10% acetic acid followed by reversed-phase HPLC was developed. Using disc-diffusion assay, the highest activity against E. coli O157:H7 was observed with extracts from F. ulmaria (hexane and ethyl acetate extracts and the unbound RP-HPLC fraction) and P. major (ethyl acetate extract and the unbound RP-HPLC fraction);E. elongate (the unbound RP-HPLC fraction) was less active. The extracts from P. major and E. elongate (the unbound RP-HPLC fractions) were equally highly active against L. monocytogenes, while those of F. ulmaria (the unbound RP-HPLC fraction) and N. sativa (hexane and ethyl acetate extracts) were less active against this pathogen. The dynamics of L. monocytogenes EGD-е and E. coli O157:H7 growth in the presence of two most potent extracts (RP-HPLC-unbound fractions of P. major and E. elongate and the hexane extract of F. ulmaria) was studied.
文摘Next generation sequencing is a powerful technology whose application in sequencing entire RNA populations (RNA-Seq) of food-borne pathogens will provide valuable insights. A problem unique to prokaryotic RNA-Seq is removal of ribosomal RNA. Unlike eukaryotic messenger RNA (mRNA), bacterial mRNA species are devoid of polyadenylation at the 3’-end and thus the approach of affinity enrichment of mRNA using oligo-dT probes is not an option. Among several approaches to enriching mRNA molecules, removal of ribosomal RNA (rRNA) by subtractive hybridization has been widely used. This approach is a single-step procedure for which several rRNA-depletion kits are commercially available. We evaluated three commercially available rRNA-depletion kits to determine their respective efficiencies of rRNA removal from Salmonella enterica serovar Typhimurium strain SL1344. The three protocols achieved varying degrees of rRNA depletion and resulted in 8 to 1000-fold enrichment of mRNA. rRNA removal probes from two of the three kits were unable to titrate out 23S rRNA species while removal of 16S rRNA was less efficient. The Ribo-Zero kit was most efficient in eliminating 16S, 23S and 5S ribosomal RNA species from the transcriptome of S. enterica serovar Typhimurium strain SL1344.
文摘This study investigated the spread of foodborne pathogens: Listeria monocytogenes, Es-cherichia coli O157:H7, Staphylococcus aureus and Salmonella in chicken sausage samples collected from retail markets in Greece and Egypt during 2006 and from Egypt through 2010. Other microbiological parameters;total viable count (TVC), lactic acid bacteria (LAB), pseudomonads (PS), staphylococci (STAPH), Brochothrix thermosphacta (BT), Enterobacteriaceae (EN), Escherichia coli (EC), yeasts and moulds (Y&M) were also counted. Egyptian chicken sausage samples were found to harbor L. mono- cytogenes, Staph. aureus and E. coli O157:H7;with frequencies equivalent to 24%, 60% and 26% of the total samples during 2006 and 37.87%, 64.44% and 41.11% of the total samples during 2010, respectively, while Greek samples were entirely free of theses pathogens. Enrichment techniques indicated the absence of Salmonella from both Greek and Egyptian samples. The obtained results may mobilize food producers and handlers in developing countries to take the due measures reducing food-borne pathogen risks and spoilage flora alongside the poultry chain.
