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1.
本文介绍了用单个棉铃虫测定杀虫药剂抗性基因频率的灵敏方法。该技术是基于比较三个相等量单个棉铃虫的乙酰胆碱酯酶的活性,每个棉铃虫要用微量滴定板同时做3个试验(也可用Enppen-dorf管)(No.1-3):1)不加抑制剂(No.1);2)不加酶源(No.2);3)加一定浓度的残杀威以抑制编码敏感AceS等位基因的乙酰胆碱酯酶,但不能抑制编码抗性AceR等位基因的乙酰胆碱酯酶。如果No.1和No.3的强度一样强,说明残杀威对乙酰胆碱酯酶的活性没有影响,那么基因型应是纯合抗性(AceRR,No3=No.1)。No.2和地.3的强度一样弱时,说明残杀威完全抑制了乙酰碱酯酶的活性,那么基因型应是纯合敏感(AceSS,No.3=No.2)。No.3的强度介于No.1(强)和No.2(弱)之间显示出残杀威部分地抑制了乙酰胆碱酯酶的活性;基因型是杂合型(AceSR,No.2<No.3<No.1)。作者用该方法测定了1995,1996两年从河北省邯郸和固安县棉田采集的棉铃虫,在邯郸棉铃虫抗药性高发地区,其抗性基因频率AceRR分别是68.3%和65.3%;但在棉铃虫抗药性低发区的固安县其抗性基因频率分别是23.9%和29.4%。  相似文献   

2.
Abstract A sensitive technique for identifying insecticide resistance genotype frequency of the Ace gene existing in natural populations of Helicoverpa armigera in China is described. The technique is based on the comparison of acetylcholinesterase (AChE) activity in 3 equal aliquots, which are taken from the homogenate of a single H. urnzigera: 1) in absence of inhibitor (well No. 1); 2) in absence of enzyme precursor (well No. 2); and 3) in presence of a concentration of propoxur inhibiting the AChE coded by the AceSallele but not by the AceRallele (well No. 3). An intensity of same strength in wells No. 1 and No. 3 indicates that propoxur has no effect on AChE activity, and the genotype should be AceRR(when well No. 3 = well No. 1). A same weak intensity in well No. 2 and No. 3 (and a strong intensity in well No. l), indicates that propoxur completely inhibited AChE activity; and the genotype should be AceSs(when well No. 3 = well No. 2). Well No. 3 displaying an intermediate intensity between well No. 1 (strong intensity) and well No. 2 (weak intensity) indicates that AChE activity was partially inhibited by the propoxur concentration and genotype should be AceRs(when well No. 2<well No. 3<well No. 1). The genotype frequency was determined in 1995 and 1996. the AceSSis 76. 1%, 70. 6% for low resistance populations respectively whereas the AceRRis 68. 3%, 65. 3% for high resistance population respectively.  相似文献   

3.
目的:探讨和总结腰-硬联合麻醉在老年人手术中的应用。方法:对128例老年下腹部和下肢手术患者,在腰-硬联合麻醉和硬膜外麻醉下进行手术,对其低血压发生率、镇痛效果和肌松效果情况进行研究析。结果:CSEA组低血压发生率4.67%,镇痛效果优为89.1%,肌松效果优为90.6%;CEA组低血压发生率17.18%,镇痛效果组优为67.2%,肌松效果优为60.9%。结论:老年人下腹部和下肢手术应用CSEA效果满意,安全性好。  相似文献   

4.
In South Dakota, the status of equid well being is relatively unknown. This study sought to (a) gain understanding about the current perceptions of nonhuman animal well being in South Dakota, with an emphasis on horses and other equids; (b) determine the level of care equids are reportedly receiving and the perceived challenges to equine well being in South Dakota, and (c) determine if people from diverse geographical locations (east or west of the Missouri River) have similar views on the well being of equids in South Dakota. Respondents indicated the current level of equid well being in South Dakota is sufficient, but there is room for improvement. Current challenges for the equid population of South Dakota were the high annual cost of horse care, poor horsemanship, dental problems, and whether caregivers understand basic equine care. Several significant associations arose between where a respondent lives (Western or Eastern South Dakota) and their level of agreement with various statements. The results provide a benchmark to gauge well being and help give direction for future educational needs that can continue to improve equid care.  相似文献   

5.
Kuhnle  U.  Schwarz  H. P.  Löhrs  U.  Stengel-Ruthkowski  S.  Cleve  H.  Braun  A. 《Human genetics》1993,92(6):571-576
We report on 46,XX true hermaphroditism and 46,XX maleness coexisting in the same pedigree, with maternal as well as paternal transmission of the disorder. Molecular genetic analysis showed that both hermaphrodites as well as the 46,XX male were negative for Y-chromosomal sequences. Thus, this pedigree is highly informative and allows the following conclusions: first, the maternal as well as paternal transmission of the disorder allows the possibility of an autosomal dominant as well as an X-chromosomal dominant mode of inheritance; second, testicular determination in the absence of Y-specific sequences in familial 46,XX true hermaphrodites as well as in 46,XX males seems to be due to the varying expression of the same genetic defect; and third, there is incomplete penetrance of the defect.  相似文献   

6.
禹城地区陆气相互作用耦合模式和观测研究   总被引:12,自引:1,他引:11  
姚德良  谢正桐  李家春 《生态学报》2000,20(6):1076-1082
论述了陆气相互作用研究在人类生存环境与发展区域经济中的重要意义与研究现状。在原有研究工作基础上,针对中国科学院禹试验城站地区麦田陆气水热传输过程,提出了一个多层陆气耦合模式。对植被内部湍流交换的物理过程作了深入研究,特别考虑了叶片气孔为非饱和水汽条件下的交换情况,并且给出了修正后的根系吸水模式。陆气耦俣模式分别对大气、植被、土壤作多层划分,以助于细致了解沿高度分布的各种物理量。利用本模式对中国科学  相似文献   

7.
A simple method of recovering DNA from agarose gel that is fast, inexpensive, and friendly both to operators and environment is described. Two rows of wells are made in an agarose gel, and a DNA sample is loaded into the well nearest to the negative pole for separation by electrophoresis. Recovery is accomplished by pipetting the DNA-containing TAE buffer from the well near the positive pole after target DNA fragments have migrated into the well. A recovery rate of up to 94 +/- 2.3% was observed with this method.  相似文献   

8.
When performing histology of softer biomaterials, aspiration disrupts the cellular and molecular location information. This study aims to develop a cryosectionable well insert able to preserve the biomaterial and cell's original 3D conformation from the well to histology analysis. The well insert is composed of a paraffin‐coated gelatine pill. Within the coated capsule, the human epithelial cell line (NS‐SV‐AC) is cultured in Matrigel, GrowDex, Myogel, Myogel + GrowDex, or cell culture media for 14 days. At 0 and 14 days, the samples are frozen in liquid nitrogen and cryotome is used to create sections. The slides are stained by Sirius Red and immunohistochemistry using antibodies human collagens I–V and human Ki‐67. Sirius Red shows pink shades of biomaterials and the best cellular vertical distribution throughout the sagittal section of the well is achieved with Matrigel, GrowDex, and Myogel + GrowDex; in Myogel and media, the cells sink. For collagen protein expression, only Matrigel induces a notable difference while in the other materials, collagen staining is weak or difficult to distinguish from endogenous collagens. Ki‐67 expression is maintained over time. The 3D‐cryo well insert provides a new time‐lapse histology perspective of analysis for liquid or gel cultures that maintains cells and macromolecules in their unaltered in‐well configuration.  相似文献   

9.
Feeding mechanics of vertebrates depend on physical constraints of the surrounding media, water or air. Such functions are inseparably combined with form. The aim of this study is to show this linkage for the pleurodiran freshwater turtle Pelusios castaneus and, additionally, to point out the major functional and biomechanical distinctions between aquatic and terrestrial feeding turtles as well as several intermediate forms. Gross morphological investigations of skull, hyoid, tongue, and connected musculature, as well as scanning electron microscopy of the tongue surface, show typical features of an aquatic feeder, e.g., strongly developed hyoid apparatus vs. a small tongue with only moderate papillae, and massive jaw and hyoid musculature. Additionally, the special function of the esophagus during feeding is investigated to elucidate the problems of a bidirectional feeder. The esophagus is highly distensible in order to store the excess water sucked in during feeding until the prey is fixed by the jaws. The distension is probably achieved by a coincidence of active (branchial horn) as well as passive (water) components. P. castaneus is a feeding generalist, and is well adapted to the aquatic medium in terms of its functional as well as morphological features.  相似文献   

10.
A general nonparametric approach to asymptotic multiple test procedures is proposed which is based on relative effects and which includes continuous as well as discontinuous distributions. The results can be applied to all relevant multiple testing problems in the one‐way layout and include the well known Steel tests as special cases. Moreover, a general estimator for the asymptotic covariance matrix is considered that is consistent even under alternative. This estimator is used to derive simultaneous confidence intervals for the relative effects as well as a test procedure for the multiple nonparametric Behrens‐Fisher problem.  相似文献   

11.
Current genetic investigations are performed both on the basis of a rational and biologically based choice of candidate genes and through genome wide scans. Nonetheless, lack of replication is a common problem in psychiatric genetics as well as in other genetic fields. There are a number of reasons for this inconsistency, among them a well known but poorly considered issue is gene coverage. The aim of the present paper is to focus on this well known and defectively deemed bias, especially when a candidate gene approach is chosen. The rational and the technical feasibility of this proposal are discussed as well as a survey of current investigations. The known consistent methodology to fix this bias is also discussed.Key Words: Candidate genes, association studies, psychiatry genetics, methodology.  相似文献   

12.
An analysis of the energy return on investment (EROI) of natural gas obtained from horizontal, hydraulically fractured wells in the Marcellus Shale was conducted using net external energy ratio methodology and available data and estimates of energy inputs and outputs. Used as sources of input data were estimates of carbon dioxide and nitrogen oxides emitted from the gas extraction processes, as well as fuel‐use reports from industry and other sources. Estimates of quantities of materials used and the associated embodied energy as well as other energy‐using steps were also developed from available data. Total input energy was compared with the energy expected to be made available to end users of the natural gas produced from a typical Marcellus well. The analysis indicates that the EROI of a typical well is likely between 64:1 and 112:1, with a mean of approximately 85:1. This range assumes an estimated ultimate recovery (EUR) of 3.0 billion cubic feet (Bcf) per well. EROI values are directly proportionate to EUR values. If the EUR is greater or lesser than 3 Bcf, the EROI would be proportionately higher or lower. EROI is also sensitive to the energy used or embedded in gathering and transmission pipelines and associated infrastructure and energy used for their construction, energy consumed in well drilling and well completion, and energy used for wastewater treatment.  相似文献   

13.
关于植物光合作用的量子分析   总被引:2,自引:0,他引:2  
以无限深势阱为模型,应用量子力学微扰理论计算了叶绿素中电子跃迁几率,并且求得电子对阱壁产生的压力以及所做的构像功。研究结果表明:只有外场频率与叶绿素的固有频率相等时电子才发生跃迁,从而导致叶绿素吸收中心波长432nm的蓝光和662nm红光。当电子跃迁到高能级,对阱壁的压力增大,阱壁被拓宽,激发电子做了构像功,激发了酶的活性,促使植物光合作用。  相似文献   

14.
Incoherent scattering of a probing wave by Langmuir fluctuations trapped and enhanced near a local minimum of the electron density (plasma density well) in plasma with a parabolic density profile is considered. Steady-state amplitudes of fluctuations are calculated for arbitrary velocity distribution functions of plasma particles with allowance for electron collisions. It is shown that quasi-periodic oscillations with two characteristic scales can be present in the spectrum of the plasma line. The smaller scale is due to the wellknown effect of discretization of the spectrum of Langmuir fluctuations in a plasma density well. The larger scale is associated with the generation of scattered waves in two spatial regions and subsequent interference of these waves at the exit from the density well. Oscillations with this scale are more stable under unsteady plasma conditions and can be more often observed in experiments. The results of this work can be used to experimentally determine the plasma parameters, such as the electron collision frequency and the size and lifetime of the plasma density well.  相似文献   

15.
Berman and Schoenfeld used matrix transformations to study unidentifiable pool models. It is possible to use the method to examine if two models are output-indistinguishable, that is, if given the nature of tracer injections and observations, the two models have the same responses. The method is applied to two three-pool models for whole-body cholesterol metabolism. The indistinguishability of a mammillary model from a catenary model is proved using matrix transformations. The method is used in two ways, directly as well as after simplifying the problem. The two ways, as well as an analysis of the converse, help to show how the method is to be applied as well as the strengths and weaknesses of the method.  相似文献   

16.
The role of Nrf2 in disease prevention and treatment is well documented; however the specific role of Nrf2 in skeletal muscle is not well described. The current study investigated whether Nrf2 plays a protective role in an STZ-induced model of skeletal muscle atrophy.  相似文献   

17.
Sunspots seem to follow a well-established ten-to-eleven-year cycle. There is reason to suspect a twenty-to-twenty-two-year cycle as well. Less well known is an eighty-to-one-hundred-year sunspot cycle. Curiously, the snowfall record for Rochester, New York, shows indications of the solar spot cycles.  相似文献   

18.
We investigated the effect of optical thick metal films on the surface-enhanced Raman scattering (SERS) activity of individual Au nanoparticle (NP) monomers and dimers. The film presence is revealed to be positive for the SERS activity of individual NP monomers, while it is not always positive for the electromagnetic enhancement at hot spots for SERS of the dimer, which is explained well by our numerical simulations. The polarized SERS signals from the NP dimer are elucidated well in terms of the plasmon hybridization of the dimer. SERS contributions both from individual NP surfaces and the junction between the NP and its supporting substrate were discussed as well.  相似文献   

19.
It is now well established that fertility of of young patients is compromised after the radiotherapy treatment for malignant diseases. This paper summarizes the main data concerning the fertility of young patients after radiotherapy treatment. The information of the patients as well as the prevention are the subject of this review.  相似文献   

20.
The fission yeast Schizosaccharomyces pombe (S. pombe) is now well established as a versatile genetic model organism. It is widely used to analyse the basic eukaryotic cell cycle during vegetative growth and it is also well suited to studies on the elementary processes of sexual reproduction, including intercellular communication and signal transduction in zygote formation, as well as meiosis before sporulation. Systematic mutant screening has contributed much to our current understanding of unicellular differentiation in S. pombe, and structural analysis has revealed a simplified meiotic prophase with abundant crossing-over but no homologue synapsis. This article is a personal account of how this branch of fission yeast genetics has developed.  相似文献   

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