为了研究常用杀虫剂对苹果黄蚜(Aphis citricola Van der Goot)及其天敌昆虫异色瓢虫(Harmonia axyridis Pallas)不同时间段的毒力及选择性,解决有害生物化学防治与生物防治的矛盾,本试验采用滤纸片法测定了7种杀虫剂对苹果黄蚜和异色...为了研究常用杀虫剂对苹果黄蚜(Aphis citricola Van der Goot)及其天敌昆虫异色瓢虫(Harmonia axyridis Pallas)不同时间段的毒力及选择性,解决有害生物化学防治与生物防治的矛盾,本试验采用滤纸片法测定了7种杀虫剂对苹果黄蚜和异色瓢虫的室内毒力,并分析了各杀虫剂对两种昆虫的选择毒力.结果表明,10%烯啶虫胺水剂对苹果黄蚜和异色瓢虫的毒力最高,21%噻虫嗪悬浮剂对异色瓢虫的选择安全性最高.21%噻虫嗪悬浮剂具有较高的正向选择性,既可有效控制苹果黄蚜,同时还具有较高的毒力选择性,其适合在果园与蚜虫天敌异色瓢虫协同防治苹果黄蚜.展开更多
Eighty four throat swabs were obtained from Basrah General Hospital inpatients （N = 34）： 17 were suffering from renal failure and the other 17 were diabetics; and from outpatients （N = 50）. Throat swabs were cult...Eighty four throat swabs were obtained from Basrah General Hospital inpatients （N = 34）： 17 were suffering from renal failure and the other 17 were diabetics; and from outpatients （N = 50）. Throat swabs were cultured first in the selective media Ashdown＇s broth then subcultured on Ashdown＇s agar to isolate Burkholderia pseudomallei which was recovered from seven cases （8.33%）. Four isolates were from renal failure patients （23.53%）, two from diabetic patients （11.76%） and the seventh isolate was from an outpatient with tonsillitis. All isolates were able to produce capsules, form filament chains, exhibit swarming motility and were arabinose non assimilators （Ara-） indicative of their virulence. Additionally, isolated B. pseudomallei were found to produce protease, lipase, hemolysin, and lecithinase and were able to produce biofilm, the root of many troublesome persistent infections that resist antibiotic treatment. Susceptibility of the seven isolates of B. pseudomallei toward 11 antibiotics was assessed, isolates were found multiply resistant to all antibiotics apart from ciproflaxin. This study confirms for the first time isolation of B. pseudomallei from immunocompromised patients in Basrah city of Iraq and describes their virulence potentials.展开更多
The selective toxicity of six kinds of insecticides, including imidacloprid, imidacloprid+synergist (SV1), fenvalerate, endosulfan, methomyl and dimethoate, between the green peach aphid (Myzus persicae Sulzer) a...The selective toxicity of six kinds of insecticides, including imidacloprid, imidacloprid+synergist (SV1), fenvalerate, endosulfan, methomyl and dimethoate, between the green peach aphid (Myzus persicae Sulzer) and two species of ladybirds (Coccinella septempunctata Linnaeus and Propylaea japonica Thunbery), was investigated in the laboratory. The results showed that both imidacloprid WP and imidacloprid+synergist (SV1) EC possessed the highest toxicity to the aphids. Between C. septempunctata and M. persicae and between P. japonica and M. persicae, the selective toxicity ratios (STRs) of imidacloprid WP, imidacloprid+ synergist (SV1) EC and endosulfan EC were 37.6 and 13.0, 9.84 and 7.75, 54.0 and 7.28 respectively. All of them showed rather high selective toxicity. The STRs of fenvalerate EC, dimethoate EC and methomyl EC were all very low, ranging from 0.02 to 0.21, indicating their low degree of safety to the two species of ladybirds. The results demonstrated that imidacloprid WP and imidacloprid+SV1 EC not only had rather high toxicity to the aphids, but also reduced strikingly the reproduction rate and fecundity of the survival aphids. Insecticides can induce the relative fitness of insects decrease. Among the six insecticides tested with M. persicae, the following were insecticides and the order of induction was: imidacloprid + SV1> imidacloprid > endosulfan > methomyl > fenvalerate > dimethoate.展开更多
To study the quasispecies diversity of porcine reproductive and respiratory syndrome virus (PRRSV), open reading frame 5 (ORF5) of strain SD0612 was amplified and cloned. Sixty clones of ORF5 were sequenced and analyz...To study the quasispecies diversity of porcine reproductive and respiratory syndrome virus (PRRSV), open reading frame 5 (ORF5) of strain SD0612 was amplified and cloned. Sixty clones of ORF5 were sequenced and analyzed with DNAStar software. Nucleic acid sequence homology was 97.7%-100%, with 78 mutations observed. Among these 60 clones, the sequences of 17 clones were identical and recognized as the dominant quasispecies of strain SD0612. Evolution of SD0612 quasispecies diversity under antibody selective pressure was also studied. SD0612 was passed continuously in the Marc-145 cell line over 40 passages in 6 independent lineages. SD0612 antiserum was not added to lineage A, B, and C cultures; however, antiserum was added to culture medium for lineages D, E, and F. PRRSV ORF5 was then amplified, cloned, and sequenced from each of the 6 lineages, designated as A40-F40. F40 was further passed in Marc-145 cells using 6 independent lineages with or without F40 antiserum for another 40 passages. ORF5 from the 6 newly-derived virus lineages, which we designated as a40-f40, were amplified, cloned and sequenced. The proportion of dominant quasispecies increased with passage number in cell cultures supplemented with antibodies, but decreased when antibodies were lacking. Our work has demonstrated a diversity of quasispecies for ORF5 in PRRSV SD0612. Antibody selective pressure was able to significantly influence quasispecies diversity and promote a dominant quasispecies that was able to evade immune reactions.展开更多
文摘为了研究常用杀虫剂对苹果黄蚜(Aphis citricola Van der Goot)及其天敌昆虫异色瓢虫(Harmonia axyridis Pallas)不同时间段的毒力及选择性,解决有害生物化学防治与生物防治的矛盾,本试验采用滤纸片法测定了7种杀虫剂对苹果黄蚜和异色瓢虫的室内毒力,并分析了各杀虫剂对两种昆虫的选择毒力.结果表明,10%烯啶虫胺水剂对苹果黄蚜和异色瓢虫的毒力最高,21%噻虫嗪悬浮剂对异色瓢虫的选择安全性最高.21%噻虫嗪悬浮剂具有较高的正向选择性,既可有效控制苹果黄蚜,同时还具有较高的毒力选择性,其适合在果园与蚜虫天敌异色瓢虫协同防治苹果黄蚜.
文摘Eighty four throat swabs were obtained from Basrah General Hospital inpatients （N = 34）： 17 were suffering from renal failure and the other 17 were diabetics; and from outpatients （N = 50）. Throat swabs were cultured first in the selective media Ashdown＇s broth then subcultured on Ashdown＇s agar to isolate Burkholderia pseudomallei which was recovered from seven cases （8.33%）. Four isolates were from renal failure patients （23.53%）, two from diabetic patients （11.76%） and the seventh isolate was from an outpatient with tonsillitis. All isolates were able to produce capsules, form filament chains, exhibit swarming motility and were arabinose non assimilators （Ara-） indicative of their virulence. Additionally, isolated B. pseudomallei were found to produce protease, lipase, hemolysin, and lecithinase and were able to produce biofilm, the root of many troublesome persistent infections that resist antibiotic treatment. Susceptibility of the seven isolates of B. pseudomallei toward 11 antibiotics was assessed, isolates were found multiply resistant to all antibiotics apart from ciproflaxin. This study confirms for the first time isolation of B. pseudomallei from immunocompromised patients in Basrah city of Iraq and describes their virulence potentials.
文摘The selective toxicity of six kinds of insecticides, including imidacloprid, imidacloprid+synergist (SV1), fenvalerate, endosulfan, methomyl and dimethoate, between the green peach aphid (Myzus persicae Sulzer) and two species of ladybirds (Coccinella septempunctata Linnaeus and Propylaea japonica Thunbery), was investigated in the laboratory. The results showed that both imidacloprid WP and imidacloprid+synergist (SV1) EC possessed the highest toxicity to the aphids. Between C. septempunctata and M. persicae and between P. japonica and M. persicae, the selective toxicity ratios (STRs) of imidacloprid WP, imidacloprid+ synergist (SV1) EC and endosulfan EC were 37.6 and 13.0, 9.84 and 7.75, 54.0 and 7.28 respectively. All of them showed rather high selective toxicity. The STRs of fenvalerate EC, dimethoate EC and methomyl EC were all very low, ranging from 0.02 to 0.21, indicating their low degree of safety to the two species of ladybirds. The results demonstrated that imidacloprid WP and imidacloprid+SV1 EC not only had rather high toxicity to the aphids, but also reduced strikingly the reproduction rate and fecundity of the survival aphids. Insecticides can induce the relative fitness of insects decrease. Among the six insecticides tested with M. persicae, the following were insecticides and the order of induction was: imidacloprid + SV1> imidacloprid > endosulfan > methomyl > fenvalerate > dimethoate.
文摘To study the quasispecies diversity of porcine reproductive and respiratory syndrome virus (PRRSV), open reading frame 5 (ORF5) of strain SD0612 was amplified and cloned. Sixty clones of ORF5 were sequenced and analyzed with DNAStar software. Nucleic acid sequence homology was 97.7%-100%, with 78 mutations observed. Among these 60 clones, the sequences of 17 clones were identical and recognized as the dominant quasispecies of strain SD0612. Evolution of SD0612 quasispecies diversity under antibody selective pressure was also studied. SD0612 was passed continuously in the Marc-145 cell line over 40 passages in 6 independent lineages. SD0612 antiserum was not added to lineage A, B, and C cultures; however, antiserum was added to culture medium for lineages D, E, and F. PRRSV ORF5 was then amplified, cloned, and sequenced from each of the 6 lineages, designated as A40-F40. F40 was further passed in Marc-145 cells using 6 independent lineages with or without F40 antiserum for another 40 passages. ORF5 from the 6 newly-derived virus lineages, which we designated as a40-f40, were amplified, cloned and sequenced. The proportion of dominant quasispecies increased with passage number in cell cultures supplemented with antibodies, but decreased when antibodies were lacking. Our work has demonstrated a diversity of quasispecies for ORF5 in PRRSV SD0612. Antibody selective pressure was able to significantly influence quasispecies diversity and promote a dominant quasispecies that was able to evade immune reactions.
