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1.
[目的]通过对H IV-1在母婴传播的个体间病毒基因亚型和准种的差异性研究揭示H IV-1在母婴传播过程中的变异规律.[方法]提取H IV-1感染母亲及其子女共4例的血浆中总RNA,通过逆转录多聚酶链反应(RT-PCR)获得H IV-1 env基因的C2-V5区域片段,纯化后连接至T载体,转化至Top10大肠埃希菌内增殖,通过蓝白筛选获得阳性克隆,阳性克隆为模板行PCR,产物进行构象敏感性凝胶电泳(CSGE)分析,挑选优势准种和劣势准种测序.[结果]第一对母亲准种复杂性较其子女低,母子之间各准种的核苷酸序列高度同源,均为C亚型;第二对母亲准种复杂性较其子女高,母子之间各准种的核苷酸序列高度同源,母子均为AE亚型.[结论]H IV-1在母婴传播过程中亚型不发生变化,病毒准种在传播过程中可能具有选择性,进入新宿主后因环境变化而被重新筛选,二者可能共同导致优势/劣势准种的变化.此外,母婴之间准种的复杂性与其宿主的免疫状态有关.  相似文献   

2.
为分析和解释2个小分子抑制剂ADS-J1和ADS-J2与艾滋病病毒蛋白gp41的抑制机理,通过采用理论计算的方式把抑制剂和gp41蛋白疏水性空穴对接,得到了可能的结合方式,并通过采用分子动力学和MM/PBSA相结合的方法,确定蛋白质和抑制剂的具体结合方式和结合自由能,并且获得了抑制剂和蛋白的精确结合构型和相互作用力,明...  相似文献   

3.
以Pt（Ⅱ）离子配位化合物为例，研究了该配合物进行取代反应的一般机理，讨论了影响形成平面正方形配合物取代反应的主要因素．  相似文献   

4.
Epstein-Barr virus(EBV),a human gammaherpesvirus carried by more than 90% of the world’s population,is associated with malignant tumors such as Burkitt’s lymphoma(BL),Hodgkin lymphoma,post-transplant lymphoma,extra-nodal natural killer/T cell lymphoma,and nasopharyngeal and gastric carcinomas in immune-compromised patients.In the process of infection,EBV faces challenges:the host cell environment is harsh,and the survival and apoptosis of host cells are precisely regulated.Only when host cells receive sufficient survival signals may they immortalize.To establish efficiently a lytic or long-term latent infection,EBV must escape the host cell immunologic mechanism and resist host cell apoptosis by interfering with multiple signaling pathways.This review details the apoptotic pathway disrupted by EBV in EBV-infected cells and describes the interactions of EBV gene products with host cellular factors as well as the function of these factors,which decide the fate of the host cell.The relationships between other EBV-encoded genes and proteins of the B-cell leukemia/lymphoma(Bcl) family are unknown.Still,EBV seems to contribute to establishing its own latency and the formation of tumors by modifying events that impact cell survival and proliferation as well as the immune response of the infected host.We discuss potential therapeutic drugs to provide a foundation for further studies of tumor pathogenesis aimed at exploiting novel therapeutic strategies for EBV-associated diseases.  相似文献   

5.
In our previous work we reported that HIV Tat and 6 cysteine rich peptides of Tat induce tumor necrosis factor-related apoptosis-induced ligand (TRAIL) in human monocytes (Yang et al., 2003). Here our results showed that HIV Tat and Tat cysteine rich peptide increase CCR5 expression in human monocytes, and this activity is inhibited by rabbit anti-Tat. Boiled Tat does not increase CCR5 expression in monocytes. These results provide insight into a new mechanism by which HIV Tat plays a key role in the pathogenesis of HIV-1 infection.  相似文献   

6.
槲皮素对金属离子具有强烈的螯合作用。本文研究表明在pH4．6的HAc—NaAc缓冲液中，槲皮素能与Cu（Ⅱ）形成稳定的配合物，在紫外光谱中其吸收带Ⅰ比单独槲皮素红移了59nm。采用等摩尔连续变化法测得槲皮索-Cu（Ⅱ）配合物的配位比为2：1，采用平衡移动法测得配合物的稳定常数为2．0410^8。并初步探讨了槲皮素与Cu（Ⅱ）配位的部位是30H～4C=0。  相似文献   

7.
Mycoplamas are a group of wall-less prokaryotes widely distributed in nature, some of which are pathogenic for humans and animals. There are many lipoproteins anchored on the outer face of the plasma membrane, called lipid-associated membrane proteins （LAMPs）. LAMPs are highly antigenic and could undergo phase and size variation, and are recognized by the innate immune system through Toll-like receptors （TLR） 2 and 6, LAMPs can modulate the immune system, and could induce immune cells apoptosis or death. In addition, they may associate with malignant transformation of host cells and are also considered to be cofactors in the progression of AIDS.  相似文献   

8.
金属(Ni、Co、Zn)--Salen配合物的合成及性质研究   总被引：16，自引：0，他引：16  
本论述了水杨醛与乙二胺，丙二胺，邻苯二胺，对苯二胺合成西佛碱及西佛碱与Co(Ⅱ），Ni(Ⅱ),Zn(Ⅱ)合成Salen金属配合物，这些化合物均被1HNMR，IR和元素分析证实，并讨论它们的电导，紫外，可见光光谱性质。  相似文献   

9.
Objective: A series of 2-benzylideneaminonaphthothiazoles were designed and synthesized incorporating the lipo- philic naphthalene ring to render them more capable of penetrating various biomembranes. Methods: Schiff bases were synthe- sized by the reaction of naphtha[1,2-d]thiazol-2-amine with various substituted aromatic aldehydes. 2-(2'-Hydroxy)ben- zylideneaminonaphthothiazole was converted to its Co(II), Ni(II) and Cu(II) metal complexes upon treatment with metal salts in ethanol. All the compounds were evaluated for their antibacterial activities by paper disc diffusion method with Gram positive Staphylococcus aureus and Staphylococcus epidermidis and Gram negative Escherichia coli and Pseudomonas aeruginosa bac- teria. The minimum inhibitory concentrations of all the Schiff bases and metal complexes were determined by agar streak dilution method. Results: All the compounds moderately inhibited the growth of Gram positive and Gram negative bacteria. In the present study among all Schiff bases 2-(2'-hydroxy)benzylideneaminonaphthothiazole showed maximum inhibitory activity and among metal complexes Cu(II) metal complex was found to be most potent. Conclusion: The results obtained validate the hypothesis that Schiff bases having substitution with halogens, hydroxyl group and nitro group at phenyl ring are required for the antibacterial activity while methoxy group at different positions in the aromatic ring has minimal role in the inhibitory activity. The results also indicated that the metal complexes are better antibacterial agents as compared to the Schiff bases.  相似文献   

10.
Aging is one of the contributing risk factors for kidney diseases. Accumulating evidence prompts the view that telomere length in kidney tissue cells is an indicator for organismal aging. Previously identified aging markers (cathelin-related antimicrobial peptide (CRAMP), stathmin, elongation factor-1α (EF-1α), and chitinase) were associated not only with telomere driven aging in mice but also with human aging and chronic diseases. This study focuses on the relationship between these biomarkers and IgA nephropathy (IgAN) progression in the Chinese population. For 260 individuals, the four markers are determined in blind datasets using direct enzyme-linked immunosorbent assay (ELISA) and immunofluorescence staining. The expression levels of CRAMP and chitinase increased in blood plasma, urine, and kidney tissues during human IgAN progression. And for the other nephropathy, such as systemic lupus erythematosus (SLE), diabetic nephropathy (DN), and focal segmental glomerulosclerosis (FSGS), there is no protein upregulation with telomere shortening. Moreover, a combination of CRAMP and chitinase can distinguish patients with IgAN from healthy individuals with 88.2%/92.5% (plasma) and 74.3%/84.2% (urine) sensitivity/specificity. These data provide the experimental evidence that telomere shortening and related inflammatory proteins are associated with human IgAN, and it could be a new direction for the disease progression study.  相似文献   

11.
This paper examines the occupational attainment of highly educated adult immigrants by employing a secondary analysis of three waves of the Longitudinal Survey of Immigrants to Canada that provide data on immigrant arrivals in 2000–2001. Occupational attainment is described in terms of matching immigrants’ pre-migration occupation with the main occupation reported 4?years since arrival. An occupational match typology based on skill level and skill type is developed and examined in the study in relation to socio-demographic factors, human capital characteristics, cultural factors and dispositional and situational factors. The primary focus is on the relationship between occupational matching and choice of post-secondary education (PSE) (including non-participation) pathways in Canada. Study findings show that occupational match rates are relatively low. However, notable differences are obtained for highly educated immigrants choosing to take further education in Canada, particularly at university level, which supports the argument that investment in host country PSE is a strategy to improve employment and occupational outcomes.  相似文献   

12.
Abstract

Botswana has been a host country to migrant teachers from various countries and regions of the world for many years. This paper reports on the migration motives that prompted teachers from four countries to move to Botswana to work in junior and senior secondary schools, and their attitudes towards human resource management (HRM) policies and practices in these schools. The teachers completed an 87-item questionnaire which measured four dimensions of migration push-pull factors, and HRM policy and practice issues. Multiple factors were revealed, linked to economic issues, personal circumstances, community and school-related conditions in both the home and host countries. However, the influence of each factor is related to migrants’ gender and countries of origin. As a follow-up to the above, a small, qualitative investigation was conducted. The reactions of five Botswana school managers to the HRM issues raised in the first phase were investigated by means of interviews. The results reveal the unique challenges of a diversified workforce for HRM in these schools.  相似文献   

13.
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14.
Objective： A series of 2-benzylideneaminonaphthothiazoles were designed and synthesized incorporating the lipophilic naphthalene ring to render them more capable of penetrating various biomembranes. Methods： Schiff bases were synthesized by the reaction of naphtha[1,2-d]thiazol-2-amine with various substituted aromatic aldehydes. 2-（2＇-Hydroxy）ben- zylideneaminonaphthothiazole was converted to its Co（Ⅱ）, Ni（Ⅱ） and Cu（Ⅱ） metal complexes upon treatment with metal salts in ethanol. All the compounds were evaluated for their antibacterial activities by paper disc diffusion method with Gram positive Staphylococcus aureus and Staphylococcus epidermidis and Gram negative Escherichia coli and Pseudomonas aeruginosa bacteria. The minimum inhibitory concentrations of all the Schiff bases and metal complexes were determined by agar streak dilution method. Results： All the compounds moderately inhibited the growth of Cram positive and Gram negative bacteria. In the present study among all Schiff bases 2-（2＇-hydroxy）benzylideneaminonaphthothiazole showed maximum inhibitory activity and among metal complexes Cu（Ⅱ） metal complex was found to be most potent. Conclusion： The results obtained validate the hypothesis that Schiff bases having substitution with halogens, hydroxyl group and nitro group at phenyl ring are required for the antibacterial activity while methoxy group at different positions in the aromatic ring has minimal role in the inhibitory activity. The results also indicated that the metal complexes are better antibacterial agents as compared to the Schiff bases.  相似文献   

15.
用自制的5-氯水杨醛与甘氨酸缩合,制备了一种氨基酸schiff碱配体,再将其与Cu(Ⅱ)、Zn(Ⅱ)作用,合成出了两种新型的Schiff配合物.采用元素分析、红外光谱、紫外光谱、差热热重分析、摩尔电导率等方法对化合物进行了表征,推测出化合物的组成与结构.  相似文献   

16.
This literature review uses four dimensions to classify and compare how food‐related decision‐making is conceptualized and experimentally assessed in neuroscience and other disciplines: (1) food‐related decision‐making other than the decision of what to eat that is part of each eating episode, (2) decision complexes other than the eating episode itself, (3) the evolution of food‐related decision‐making over time, and (4) the nature of food related decisions. In neuroscience in particular, food‐related decision‐making research has been dominated by studies exploring the influence of a wide range of factors on the final outcome, the type and amount of foods eaten. In comparison, the steps that are leading up to this outcome have only rarely been discussed. Neuroscientists should broaden their historically narrow conceptualization of food‐related decision‐making. Then neuroscience research could help group the numerous hypothesized influences for each of the decision complexes into meaningful clusters that rely on the same or similar brain mechanisms and that thus function in similar ways. This strategy could help researchers improve existing broad models of human food‐related decision‐making from other disciplines. The integration of neuroscientific and behavioral science approaches can lead to a better model of food‐related decision‐making grounded in the brain and relevant to the design of more effective school and nonschool lifestyle interventions to prevent and treat obesity in children, adolescents, and adults.  相似文献   

17.
Two metal (Ⅱ) complexes based on 1,3,5-triazine-2,4,6-triyltrithio-tri-acetate exhibit similar (6,3)-connected 2D layer with kgd topology. Negative and positive magnetic field effects (MFEs) on the fluorescence properties of the Mn(Ⅱ) and Zn(Ⅱ) complexes are observed, respectively.  相似文献   

18.
A new series of Schiff base ligands were synthesized by the condensation of 2-amino-5-mercaptan-l,3,4-thiadiazole and salicylaldehyde or 2,4-dihydroxybenzaldehyde and their derivatives with choroacetic acid, and further reaction with corresponding metal acetate to form metal complexes. The compositions and structures of the ligands and their complexes were characterized by elemental analysis, molar conductivities, electronic absorption spectra and infra-red spectra. Their inhibition rates to free radical, such as O2, were also tested. The results show that all of the obtained complexes display significant activities, among which the copper（Ⅱ） complexes have the best inhibitive effects.  相似文献   

19.
本文结合媒介生态环境,从可持续发展的角度提出建构发展性主持人评价体系的初步设想,初步分析了为实现主持人与媒体发展的良性循环,发展主持人队伍,构建动态、持续、全面的主持人评价、监控体系需要的元素以及在构建过程中需要注意的工作重点。  相似文献   

20.
Aluminium （Al） toxicity is one of the major limiting factors for barley production on acid soils. It inhibits root cell division and elongation, thus reducing water and nutrient uptake, consequently resulting in poor plant growth and yield. Plants tolerate Al either through external resistance mechanisms, by which Al is excluded from plant tissues or internal tolerance mechanisms, conferring the ability of plants to tolerate Al ion in the plant symplasm where Al that has permeated the plas- malemma is sequestered or converted into an innocuous form. Barley is considered to be most sensitive to Al toxicity among cereal species. Al tolerance in barley has been assessed by several methods, such as nutrient solution culture, soil bioassay and field screening. Genetic and molecular mapping research has shown that Al tolerance in barley is controlled by a single locus which is located on chromosome 4H. Molecular markers linked with Al tolerance loci have been identified and validated in a range of diverse populations. This paper reviews the （1） screening methods for evaluating Al tolerance, （2） genetics and （3） mechanisms underlying Al tolerance in barley.  相似文献   

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