对干酪乳杆菌群(Lactobacillus casei group)内5个种和4个亚种的23个代表菌株的苯丙氨酰-tRNA合成酶α亚基基因(pheS)序列和18个16S rRNA基因序列进行系统发育学分析,探索pheS基因序列分析在干酪乳杆菌群种水平鉴定中应用的可行性。分...对干酪乳杆菌群(Lactobacillus casei group)内5个种和4个亚种的23个代表菌株的苯丙氨酰-tRNA合成酶α亚基基因(pheS)序列和18个16S rRNA基因序列进行系统发育学分析,探索pheS基因序列分析在干酪乳杆菌群种水平鉴定中应用的可行性。分析结果表明,pheS基因序列群内种间的差异率在6.8%～34%之间,种内最大差异率可达3%,其变异率远高于16S rRNA基因,可作为该群内种水平鉴定的重要手段。展开更多
The nucleotide scquence of tRNAphe gene of Carp mitochondria was determined. Sequence comparisons made among Whale,Human,Xenopus laevis, Bovine, Mouse,Chicken and Carp revealed a novel conservative structure in the D....The nucleotide scquence of tRNAphe gene of Carp mitochondria was determined. Sequence comparisons made among Whale,Human,Xenopus laevis, Bovine, Mouse,Chicken and Carp revealed a novel conservative structure in the D. stem (dihydrouridine stem),which is known to vary in other vertebrate mitochondrial and eytoplasmic tRNA genes.This conservative structure contains 13 bp. When the first 7 bp of the conserviative structure were compared with the A domain recognized by RNA Pol III, we noticed partial homology between these two kinds of sequences among different species. In view of the tRNAphe gene's close position to the D loop,it is reasonable to expect extraordinary functions in this novel conservation structure.展开更多
The DNA-damaging effects of the combined pollution of heavy metal and organic contamination on earthworms were evaluated by single cell gel electrophoresis （SCGE） assay. Earthworms Eisenia andrei were exposed to sin...The DNA-damaging effects of the combined pollution of heavy metal and organic contamination on earthworms were evaluated by single cell gel electrophoresis （SCGE） assay. Earthworms Eisenia andrei were exposed to single or combined test compounds in different doses of cadmium （Cd） 5, 10, 50 mg/kg and phenanthrene （Phe） 0.5, 2.5, 12.5 mg/kg with a treatment of 14 d. In SCGE assay, isolated coelomcytes and electrophoresis were employed to determine DNA damage degree after a 14-d treatment by test compounds. The results showed that there was a significant statistical difference between earthworms treated with Cd combined Phe with them treated alone with Cd or Phe. The Olive tail moment （OTM） of SCGE assay using earthworm coelomcytes appears to be a sensitive biomarker for evaluating exposure to genotoxic compounds. These tests also revealed that the interaction between Cd and Phe to DNA damaging effects was negative, and was strongly dependent on the concentration of pollution. This study corresponds to exploratory phase in order to reveal interaction effects of heavy metal and organic contamination on earthworms and then to set up more in-depth analysis to increase progressively the understanding of the genotoxicity mechanisms involved.展开更多
Objective:To determine the susceptibility status to pyrethroid in Anopheles gambiae s.l.(An.gambiae),the distribution of kdr"Leu-Phe"mutation in malaria vectors in Benin and to compare the current frequency ...Objective:To determine the susceptibility status to pyrethroid in Anopheles gambiae s.l.(An.gambiae),the distribution of kdr"Leu-Phe"mutation in malaria vectors in Benin and to compare the current frequency of kdr"Leu-Phe"mutation to the previous frequency after long-lasting insecticide treated nets implementation.Methods:Larvae and pupae of An.gambiae s.l.mosquitoes were collected from the breeding sites in Littoral,Zou.Borgou and Alibori provinces.CDC susceptibility tests were conducted on unfed females mosquitoes aged 2-5 d old.An.gambiae mosquitoes were identified to species using PCR techniques.Molecular assays were also carried out to identify kdr mutations in individual mosquitoes.Results:The results showed that An.gambiae Malanville and Suru-lere populations were resistant to deltamethrin.Regarding An.gambiae Parakou and Bohicon populations,they were resistant to permethrin.PCR revealed 100%of mosquitoes tested were An.gambiae s.s.The L1014F kdr mutation was found in An.gambiae s.s.Malanville and Parakou at various allelic frequencies.The increase of kdr allelic frequency was positively correlated with CDC bioassays data.Conclusions:Pyrethroid resistance is widespread in malaria vector in Benin and kdr mutation is the main resistance mechanism involved.More attention may be paid for the future success of malaria control programmes based on LLINs with pyrethroids in the country.展开更多
文摘对干酪乳杆菌群(Lactobacillus casei group)内5个种和4个亚种的23个代表菌株的苯丙氨酰-tRNA合成酶α亚基基因(pheS)序列和18个16S rRNA基因序列进行系统发育学分析,探索pheS基因序列分析在干酪乳杆菌群种水平鉴定中应用的可行性。分析结果表明,pheS基因序列群内种间的差异率在6.8%～34%之间,种内最大差异率可达3%,其变异率远高于16S rRNA基因,可作为该群内种水平鉴定的重要手段。
文摘The nucleotide scquence of tRNAphe gene of Carp mitochondria was determined. Sequence comparisons made among Whale,Human,Xenopus laevis, Bovine, Mouse,Chicken and Carp revealed a novel conservative structure in the D. stem (dihydrouridine stem),which is known to vary in other vertebrate mitochondrial and eytoplasmic tRNA genes.This conservative structure contains 13 bp. When the first 7 bp of the conserviative structure were compared with the A domain recognized by RNA Pol III, we noticed partial homology between these two kinds of sequences among different species. In view of the tRNAphe gene's close position to the D loop,it is reasonable to expect extraordinary functions in this novel conservation structure.
基金The National Basic Research Program (973) of China (No. 2004CB18503)the National Natural Science Foundation of China (No.20337010) the Key Program of Basic Research of Shanghai City (No. 04JC14051)
文摘The DNA-damaging effects of the combined pollution of heavy metal and organic contamination on earthworms were evaluated by single cell gel electrophoresis （SCGE） assay. Earthworms Eisenia andrei were exposed to single or combined test compounds in different doses of cadmium （Cd） 5, 10, 50 mg/kg and phenanthrene （Phe） 0.5, 2.5, 12.5 mg/kg with a treatment of 14 d. In SCGE assay, isolated coelomcytes and electrophoresis were employed to determine DNA damage degree after a 14-d treatment by test compounds. The results showed that there was a significant statistical difference between earthworms treated with Cd combined Phe with them treated alone with Cd or Phe. The Olive tail moment （OTM） of SCGE assay using earthworm coelomcytes appears to be a sensitive biomarker for evaluating exposure to genotoxic compounds. These tests also revealed that the interaction between Cd and Phe to DNA damaging effects was negative, and was strongly dependent on the concentration of pollution. This study corresponds to exploratory phase in order to reveal interaction effects of heavy metal and organic contamination on earthworms and then to set up more in-depth analysis to increase progressively the understanding of the genotoxicity mechanisms involved.
基金funded by the President's Malaria Initiative of the U.S.Government through USAtD and the Ministere de l'Enseignement Superieur et de la Recherche Scientifique, Benin
文摘Objective:To determine the susceptibility status to pyrethroid in Anopheles gambiae s.l.(An.gambiae),the distribution of kdr"Leu-Phe"mutation in malaria vectors in Benin and to compare the current frequency of kdr"Leu-Phe"mutation to the previous frequency after long-lasting insecticide treated nets implementation.Methods:Larvae and pupae of An.gambiae s.l.mosquitoes were collected from the breeding sites in Littoral,Zou.Borgou and Alibori provinces.CDC susceptibility tests were conducted on unfed females mosquitoes aged 2-5 d old.An.gambiae mosquitoes were identified to species using PCR techniques.Molecular assays were also carried out to identify kdr mutations in individual mosquitoes.Results:The results showed that An.gambiae Malanville and Suru-lere populations were resistant to deltamethrin.Regarding An.gambiae Parakou and Bohicon populations,they were resistant to permethrin.PCR revealed 100%of mosquitoes tested were An.gambiae s.s.The L1014F kdr mutation was found in An.gambiae s.s.Malanville and Parakou at various allelic frequencies.The increase of kdr allelic frequency was positively correlated with CDC bioassays data.Conclusions:Pyrethroid resistance is widespread in malaria vector in Benin and kdr mutation is the main resistance mechanism involved.More attention may be paid for the future success of malaria control programmes based on LLINs with pyrethroids in the country.
