Honey is being used as a pure natural and as an ingredient in many foods, pharmaceuticals and cosmetics than ever before, so honey testing has become essential to maintain its healthful characteristics and protect pub...Honey is being used as a pure natural and as an ingredient in many foods, pharmaceuticals and cosmetics than ever before, so honey testing has become essential to maintain its healthful characteristics and protect public health. Tetracyclines （TCs） are used for the treatment or prevention of American and European foul broad in bee colonies which are caused especially by two species of bacteria--Paenibacillus larvae and Melissococcus pluton. The present study aimed to determine the tetracycline residues in different types of local and imported honey. The reversed-phase high performance liquid chromatography （HPLC） with ultraviolet detection （UV） was used. Tetracycline and oxytetracycline were extracted from honey with 0.01 M sodium succinate buffer. Of the examined samples, 31.25% and 12.50% had these oxytetracycline and tetracycline residues, respectively. It was observed that all the samples studied have been reported residues of tetracycline and oxytetracycline more than international standards of maximum residue limit （MRLs）.展开更多
Bee venom phospholipase A2(BvPLA2) is a lipolytic enzyme that catalyzes the hydrolysis of the sn-2 acyl bond of glycerophospholipids to liberate free fatty acids and lysophospholipids.In this work,a new BvPLA2(AccPLA2...Bee venom phospholipase A2(BvPLA2) is a lipolytic enzyme that catalyzes the hydrolysis of the sn-2 acyl bond of glycerophospholipids to liberate free fatty acids and lysophospholipids.In this work,a new BvPLA2(AccPLA2) gene from the Chinese honeybee(Apis cerana cerana) venom glands was inserted into bacmid to construct a recombinant transfer vector.Tn-5B-4(Tn) cells were transfected with the recombinant bacmid DNA for expression.Sodium dodecylsulfate-polyacrylamide gel electrophoresis(SDS-PAGE) analysis revealed a double band with molecular weights of 16 and 18 kDa.Products of hexahistidine AccPLA2 fusion protein accumulated up to 5.32% of the total cellular proteins.The AccPLA2 fusion protein was cross reactive with the anti-AmPLA2(BvPLA2 of the European honeybee,Apis mellifera) polyclonal serum.The reaction resulted in a double glycosylation band,which agrees with the band generated by the native AmPLA2 in Western blot analysis.The PLA2 activity of the total extracted cellular protein in the hydrolyzing egg yolk is about 3.16 μmol/(min·mg).In summary,the recombinant AccPLA2 protein,a native BvPLA2-like structure with corresponding biological activities,can be glycosylated in Tn cells.These findings provided fundamental knowledge for potential genetic engineering to produce AccPLA2 in the pharmaceutical industry.展开更多
文摘Honey is being used as a pure natural and as an ingredient in many foods, pharmaceuticals and cosmetics than ever before, so honey testing has become essential to maintain its healthful characteristics and protect public health. Tetracyclines （TCs） are used for the treatment or prevention of American and European foul broad in bee colonies which are caused especially by two species of bacteria--Paenibacillus larvae and Melissococcus pluton. The present study aimed to determine the tetracycline residues in different types of local and imported honey. The reversed-phase high performance liquid chromatography （HPLC） with ultraviolet detection （UV） was used. Tetracycline and oxytetracycline were extracted from honey with 0.01 M sodium succinate buffer. Of the examined samples, 31.25% and 12.50% had these oxytetracycline and tetracycline residues, respectively. It was observed that all the samples studied have been reported residues of tetracycline and oxytetracycline more than international standards of maximum residue limit （MRLs）.
基金Project (No 2007AA10Z324) supported by the National High-Tech Research and Development Program (863) of China
文摘Bee venom phospholipase A2(BvPLA2) is a lipolytic enzyme that catalyzes the hydrolysis of the sn-2 acyl bond of glycerophospholipids to liberate free fatty acids and lysophospholipids.In this work,a new BvPLA2(AccPLA2) gene from the Chinese honeybee(Apis cerana cerana) venom glands was inserted into bacmid to construct a recombinant transfer vector.Tn-5B-4(Tn) cells were transfected with the recombinant bacmid DNA for expression.Sodium dodecylsulfate-polyacrylamide gel electrophoresis(SDS-PAGE) analysis revealed a double band with molecular weights of 16 and 18 kDa.Products of hexahistidine AccPLA2 fusion protein accumulated up to 5.32% of the total cellular proteins.The AccPLA2 fusion protein was cross reactive with the anti-AmPLA2(BvPLA2 of the European honeybee,Apis mellifera) polyclonal serum.The reaction resulted in a double glycosylation band,which agrees with the band generated by the native AmPLA2 in Western blot analysis.The PLA2 activity of the total extracted cellular protein in the hydrolyzing egg yolk is about 3.16 μmol/(min·mg).In summary,the recombinant AccPLA2 protein,a native BvPLA2-like structure with corresponding biological activities,can be glycosylated in Tn cells.These findings provided fundamental knowledge for potential genetic engineering to produce AccPLA2 in the pharmaceutical industry.
