反相高效液相色谱法测定有机氯及含氮杀虫剂在水体·土壤沉积物及鱼体中的残留   总被引：6，自引：0，他引：6  

Shahid Mahboob  Ghazala  S. Sultana  Muhammad Rafique Asi  S. Nadeem  A.S. Chaudhry 《农业科学与技术》2009,10(5):9-12

[目的]测定水体、土壤沉积物以及鱼体内有机氯及含氮杀虫剂残留物,为科学评估杀虫剂残留对巴基斯坦地区公共卫生、农业和环境的影响提供依据。[方法]以食用鱼南亚野鲮为材料,设计2组体重,采用高效液相色谱法分别测定水体、土壤沉积物以及南亚野鲮体内α-硫丹、DDE、甲基对硫磷、异丙隆、呋喃丹、阿特拉津等含量。[结果]土壤沉积物中DDE的含量达（2．340±0．025）μg／g,在250～750g的南亚野鲮体内的含量分别为（0．270±0．0006）μg／g,但在水体中未发现DDE残留;不同饲料中农药残留物90％为有机磷、呋喃丹以及有机氯杀虫剂,6％为杀菌剂,仅4％为除草剂,在250～750g以及800～1300g的南亚野鲮体内硫丹的含量分别达到（0．491±0．0006）μg／g和（3．050±0．0608）μg/g,异丙隆的含量分别达到（0．010±0．0003）μg／g和（0．014±0．0006）μg／g,且随体重上升,其脂肪含量增加,积累的农药残留物则越多;硫丹、甲基对硫磷、阿特拉津和呋喃丹的含量在水体达到最大残留限量水平0．001μg／g。[结论]通过生物积累和在自然界中的运输以及再沉积作用,有机氯及其他杀虫剂的使用给全球的环境造成了严重污染,因此,在巴基斯坦已经禁止使用DDT等有机氯农药。  相似文献   

Transformation of α-EXPA1 gene leads to an improved fibre quality in Gossypium hirsutum     

Amina Yaqoob  Samina Bashir  Abdul Q. Rao  Ahmad A. Shahid 《Plant Breeding》2020,139(6):1213-1220

The Expansin protein is known for its multifaceted roles in plant growth, especially cell walls. However, very few studies have been done so far to assess the effects of expansin genes on Cotton fibre development. The present study is a successful effort to fill this gap, where the α-EXPA1 gene transformed into a local cotton variety, Gossypium hirsutum, through Agrobacterium-mediated transformation under Gossypium hirsutum Seed coat and Fibre-specific promoter (GhSCFP). The transgenic cotton plants underwent molecular characterization and fibre trait evaluation. Our results indicated that α-EXPA1 showed an up-regulated expression during the transition phase of secondary cell wall synthesis and resulted in improving the fibre parameters, especially micronaire value. Transgenic cotton fibre also showed a finer twisting under the Scanning electron microscope (SEM) as compared to non-transgenic cotton fibre samples. The fibre production is influenced by more than nine thousand genes, and the fibre improvement cannot be just achieved through a single gene transformation. However, α-EXPA1 is one of the potential candidates for cotton fibre research as it significantly improved the cotton fibre.  相似文献   

城市污泥腐殖土中活性物质分离及作用机理研究     

丁伟  牟鹏举  Muhammad Shahid Khan 《东北农业大学学报》2018,(7):38-47

生活污水处理产生的城市污泥经腐熟后形成腐殖土可作为土壤有机质来源,是生活污水处理后污泥合理循环应用重要方式。采用培养皿法研究污泥腐殖土粗提取物对种子萌发影响,利用硅胶柱分离和红外光谱法鉴定粗提物抑制种子萌发的活性物质并研究其作用机理。结果表明,污泥腐殖土粗提取物浓度增加,水萝卜、小白菜种子萌发率降低,种子萌发受抑制时间延长,玉米幼苗中SOD、POD活性升高。鉴定腐殖土中活性化合物结构为3-羟基苯甲酸,该化合物对水稻种子α-淀粉酶活性具有显著抑制作用,导致水稻种子发芽率显著降低。腐殖土严重抑制种子萌发,分离该腐殖土中活性物质并研究其作用机理,可为污泥再利用提供理论基础。  相似文献   

Effects of Bacillus coagulans supplementation on the growth performance and gut health of broiler chickens with Clostridium perfringens-induced necrotic enteritis     

Yuanyuan Wu  Yujing Shao  Bochen Song  Wenrui Zhen  Zhong Wang  Yuming Guo  Muhammad Suhaib Shahid  Wei Nie 《畜牧与生物技术杂志(英文版)》2018,(2)

Background: The poultry industry is in need of effective antibiotic alternatives to control outbreaks of necrotic enteritis(NE) due to Clostridium perfringens.Methods: This study was conducted to investigate the effects of feeding Bacil us coagulans on the growth performance and gut health of broiler chickens with C. perfringens-induced NE. Two hundred and forty 1-day-old broiler chicks were randomly assigned to a 2 × 2 factorial arrangement with two dietary B. coagulans levels(0 or 4 × 109 CFU/kg of diet) and two disease chal enge statuses(control or NE chal enged).Results: NE-induced reduction in body weight gain was relieved by the addition of B. coagulans into broiler diets compared with the NE-infected birds. NE infection damaged intestinal morphological structure, promoted intestinal C.perfringens growth and liver invasion, and enhanced anti-C. perfringens specific sI gA concentrations in the gut and specific IgG levels in serum compared with the uninfected birds. NE infection significantly(P 0.05) decreased mucin-2(at 14 d post-infection(DPI), tol-like receptor 2(TLR2, at 7 and 14 DPI), TLR4(at 7 and 14 DPI), tumor necrosis factor super family15(TNFSF15, at 7 and 14 DPI), lysozyme(LYZ, at 14 DPI) and fowlicidin-2(at 7 and 14 DPI) mR NA levels, whereas it dramatical y(P = 0.001) increased IFN-γ mR NA levels at 7 DPI. However, chal enged birds fed diets supplemented with B.coagulans showed a significant(P 0.01) decrease in gut lesion scores, decreased C. perfringens numbers in the cecum and liver, and an increase in fowlicidin-2 mR NA levels in compared with the uninfected birds. In addition, compared with the non-supplemented group, dietary inclusion of B. coagulans improved intestinal barrier structure, further increased specific sI gA levels and alkaline phosphatase(IAP) activity in the jejunum, enhanced the expression of jejunum lysozyme mR NA, and inhibited the growth, colonization, and invasion of C. perfringens; in contrast, it reduced serum-specific IgG concentrations and jejunum IFN-γ mR NA levels.Conclusion: These results indicated that dietary B. coagulans supplementation appeared to be effective in preventing the occurrence and reducing the severity of C. perfringens-induced NE in broiler chickens.  相似文献   

Regulation of sexual development of Plasmodium by translational repression     

Mair GR  Braks JA  Garver LS  Wiegant JC  Hall N  Dirks RW  Khan SM  Dimopoulos G  Janse CJ  Waters AP 《Science (New York, N.Y.)》2006,313(5787):667-669

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Emergence of novel strains of avian infectious bronchitis virus in Sweden     

Abro SH  Renström LH  Ullman K  Isaksson M  Zohari S  Jansson DS  Belák S  Baule C 《Veterinary microbiology》2012,155(2-4):237-246

Infectious bronchitis virus (IBV) causes avian infectious bronchitis, an important disease that produces severe economic losses in the poultry industry worldwide. Recent IBV infections in Sweden have been associated with poor growth in broilers, drop in egg production and thin egg shells in layers. The complete spike gene of selected isolates from IBV cases was amplified and sequenced using conventional RT-PCR. Nucleotide and amino acid sequence comparisons have shown that the recent isolates bear 98.97% genetic similarity with strains of the QX-like genotype. The phylogenetic analysis revealed that strains predominant in the nineties, which were of the Massachusetts type, have been replaced by D388/QX-like strains, however the evolutionary link could not be established. The homology between the two genotypes was 79 and 81%. Remarkably, a strong positive selection pressure was determined, mostly involving the S1 subunit of the S gene. This strong selective pressure resulted in recombination events, insertions and deletions in the S gene. Two new isolates generated from recombination were found with nucleotide sequence diverging 1.7-2.4% from the D388/QX-like branch, indicating the emergence of a new lineage. The study demonstrates a constant evolution of IBV that might be in relation to increased poultry farming, trade and vaccine pressure. The findings underscore the importance of continuous monitoring to control spread of infections, as well as to timely adjust diagnostic methods, molecular epidemiological studies, development and use of vaccines that are adapted to the changing disease scenario.  相似文献   

Flow measurements with portable cut-throat flume and broad crested weir in flat gradient channels     

Shahid Ahmad  Muhammad Yasin  M. Munir Ahmad 《Irrigation and Drainage Systems》1991,5(2):141-150

A study was conducted to evaluate the reliability of flow measurements with portable cut-throat flumes and broad-crested weirs during 1988–89 at the field hydraulic laboratory of the National Agricultural Research Centre, Islamabad. Data of flow measurements were recorded under free and submerged flow conditions with a cut-throat flume and a broad-crested weir as compared to a standard V notch. The results indicated that for free flow conditions cut-throat flumes can be used with –2.2 to 8.6% error. However, the use of cut-throat flumes under flat gradient channels may cause problem of over-topping at the upstream end. Under submerged flow conditions, the percent error in the flow measurements of –3.2 to 14.6% was observed. Therefore, cut-throat flumes cannot provide reasonable flow measurements under submerged flow conditions. For accurate flow measurements broad-crested weirs should be used with percent error of –1.5 to 5.8. Such flumes can be easily manufactured in Pakistan to suit different flow regimes and flat gradient channels.  相似文献   

Exogenous 24-Epibrassinolide Elevates the Salt Tolerance Potential of Pea (Pisum sativum L.) by Improving Osmotic Adjustment Capacity and Leaf Water Relations     

Muhammad Adnan Shahid  Rashad Mukhtar Balal  Muhammad Aslam Pervez  Tahira Abbas  Muhammad Anjum Aqeel  Atif Riaz 《Journal of plant nutrition》2015,38(7):1050-1072

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Mixtures of plant disease suppressive bacteria enhance biological control of multiple tomato pathogens     

Imran A. Siddiqui  Shahid S. Shaukat 《Biology and Fertility of Soils》2002,36(4):260-268

Plant growth-promoting rhizobacteria (PGPR) strains CHA0 (Pseudomonas fluorescens), IE-6 S⁺ (Pseudomonas aeruginosa) and 569Sm^r (Bradyrhizobium japonicum) were tested singly and in combinations for biological control against multiple tomato pathogens (root-infecting fungi and root-knot nematodes). Strains CHA0 and IE-6S⁺ inhibited in vitro growth of 569Sm^r while IE-6S⁺ suppressed CHA0. The bacterial species not only inhibited the radial growth of three root-infecting fungi, Macrophomina phaseolina, Fusarium solani and Rhizoctonia solani (AG 8), but also caused substantial mortality of Meloidogyne javanica juveniles. Used as a soil drench the three bacteria not only suppressed root-infecting fungi and root-knot nematodes but also enhanced growth of tomato plants both under glasshouse and field conditions. The suppressive effect was generally more pronounced when the bacteria were employed together. Strain IE-6S⁺ exhibited better rhizosphere colonization than CHA0 and 569Sm^r. Populations of CHA0 in the rhizosphere declined when the bacterium was used with either IE-6S⁺ and/or 569Sm^r, while populations of IE-6S⁺ in the rhizosphere were enhanced when used in combination with CHA0 and/or 569Sm^r. IE-6S⁺ was the only bacterium that colonized inner root tissues of tomato plants. When using an iron chelator to create iron deficiency in the soil, the biocontrol efficacy of the bacteria against F. solani and R. solani was enhanced while against M. phaseolina and M. javanica this activity remained unchanged. Only strain 569Sm^r gave significant suppression of M. phaseolina in both iron-deficient and iron-sufficient soils.  相似文献   

Economic reasons for conserving wild nature   总被引：2，自引：0，他引：2  

Balmford A  Bruner A  Cooper P  Costanza R  Farber S  Green RE  Jenkins M  Jefferiss P  Jessamy V  Madden J  Munro K  Myers N  Naeem S  Paavola J  Rayment M  Rosendo S  Roughgarden J  Trumper K  Turner RK 《Science (New York, N.Y.)》2002,297(5583):950-953

On the eve of the World Summit on Sustainable Development, it is timely to assess progress over the 10 years since its predecessor in Rio de Janeiro. Loss and degradation of remaining natural habitats has continued largely unabated. However, evidence has been accumulating that such systems generate marked economic benefits, which the available data suggest exceed those obtained from continued habitat conversion. We estimate that the overall benefit:cost ratio of an effective global program for the conservation of remaining wild nature is at least 100:1.  相似文献