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101.
基于生态系统服务和生态系统健康的生态风险评价——以长株潭城市群为例 总被引:1,自引:0,他引:1
基于生态系统服务和生态系统健康的生态风险评估框架为城市群生态风险管理和国土生态修复提供新的视角。以生态风险评估框架为基础,综合运用生态系统服务、生态系统健康评估模型以及相关分析法对长株潭城市群展开生态风险评价,并对风险程度进行分类。结果表明:(1)城市群的城市化水平提升,区域生态风险也随之增加。生态系统服务价值、生态系统组织、生态系统活力、生态系统弹性等生态指数呈现下降趋势。(2)人工表面比率和生态指数之间的Pearson相关系数表明,人工表面比率与生态指数之间存在负相关关系,人工表面比率是生态风险提升的关键因素。(3)城市群人工表面比率要控制在36%以下,以进行生态风险管理和国土生态修复。总的来说,评价框架可以作为区域生态风险的评价终点。 相似文献
102.
细胞自噬是植物逆境应答过程中最常见的保护机制之一。动物中,自噬相关基因抵御镉(Cd)毒害的功能研究较清楚,但植物却知之甚少。文中以芹菜品种‘皇后’为试材,采用外源Cd(终浓度为0、2、4、8mg/L)添加营养液水培处理,利用转录组测序(RNA-seq)技术筛选细胞自噬相关差异基因并进行q RT-PCR验证。结果表明Cd胁迫对芹菜植株产生了明显的毒害作用,并与浓度间产生了量效关系。在筛选的8个差异表达的自噬相关基因中,ATG8a、ATG8f、ATG13、AMPK-1、AMPK-2基因随Cd浓度升高表达上调,ATG12、VPS30和VPS34则先上调后下降,说明自噬相关基因可能通过表达上调增加了自噬小体结构以抵御Cd毒性作用;而高浓度Cd(8mg/L)可能超出芹菜的耐受范围,导致多个自噬基因又出现表达下调趋势。以上结果有助于后期自噬相关基因的功能研究,为进一步探讨芹菜对Cd胁迫的耐性机制提供参考依据。 相似文献
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Wei Zhao Lan Yao Min Zhuang Yuan-Long Lin Xiao-Hong Chen Li Wang Bo Song Ya-Shuang Zhao Yun Xiao Feng-Min Zhang Fu-Xiang Wang Hong Ling 《PLoS neglected tropical diseases》2022,16(9)
BackgroundHuman immunodeficiency virus (HIV) and enteric parasite co-infection not only aggravates the clinical symptoms of parasites but also accelerates acquired immunodeficiency syndrome (AIDS) progression. However, co-infection research on men who have sex with men (MSM), the predominant high-risk population of HIV/AIDS in China, is still limited. In this study, we investigated the epidemiology of enteric parasites, risk factors, and associations with clinical significance in an MSM HIV/AIDS population in Heilongjiang Province, northeast China.MethodsWe recruited 308 MSMs HIV/AIDS patients and 199 HIV-negative individuals in two designated AIDS hospitals in Heilongjiang between April 2016 and July 2017. Fresh stool samples were collected. DNA extraction, molecular identification, and genotyping of Cryptosporidium species, Entamoeba histolytica, Cyclospora cayetanensis, Enterocytozoon bieneusi, and Blastocystis hominis were performed. Fourteen diarrhea-related pathogens were examined to exclude the influence of other bacterial pathogens on diarrhea incidence.Results31.5% of MSM HIV/AIDS participants were infected with at least one parasite species, a significantly higher proportion than that found in the HIV-negative individuals (2.5%). E. bieneusi presented the highest prevalence, followed by B. hominis, E. histolytica, Cryptosporidium spp., and C. cayetanensis. Warm seasons were the risk factor for parasitic infections in this population [odds ratio (OR) = 2.6, 95% CI: 1.47–4.57]. In addition, these individuals showed a higher proportion (35.8%) of present diarrhea (PD) compared with men who have sex with women (MSW) with HIV/AIDS (16.7%). The infection proportions of both Cryptosporidium spp. and E. histolytica were significantly higher in the PD. E. bieneusi infection was more prevalent in the historic diarrhea (HD) group. CD4+ T cell counts in the MSM patients with the above three parasites were significantly lower. New species and genotypes were found, and MSM patients had a wider range of species or genotypes.ConclusionsEnteric parasitic infection was prevalent in the MSM HIV/AIDS population, especially in patients with present diarrhea during warm seasons. E. histolytica and B. hominis should also be considered high-risk parasites for opportunistic infections in AIDS patients in addition to Cryptosporidium spp. 相似文献
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108.
In the presence of 12-O-tetradecanoylphorbol-13-acetate (TPA) or the non-TPA-type tumor promoter, palytoxin, recombinant human insulin growth factor-I (IGF-I) and insulin synergistically stimulate prostaglandin production in rat liver cells (the C-9 cell line). Combinations fo palytoxin or TPA with recombinant human IGF-I or insulin also synergistically stimulate deesterification of c ellular lipids in C-9 cells prelabelled with [3H]arachidonic acid. With both types of stimulations, prostaglandin production or deesterification, the synergistic response of the IGF-I and insulin is greater with palytoxin than with TPA. Production of prostaglandin E2 and F2α by squirrel monkey smooth muscle cells incubated in the presence of TPA and insulin also is greater than the sum of the effects taken independently. 相似文献
109.
Site-directed mutagenesis by combination of homologous recombination and DpnI digestion of the plasmid template in Escherichia coli 总被引:1,自引:0,他引:1
A rapid site-directed mutagenesis strategy using homologous recombination and DpnI digestion of the template in Escherichia coli is described. Briefly, inverse polymerase chain reaction amplification of the entire circular plasmid was performed by mutagenic primers with overlapping sequences ( approximately 15 bp) for generating PCR products with approximately 15 bp of homology on the terminal ends. On direct transformation of the amplified PCR products into restriction endonuclease DpnI-expressing E. coli BUNDpnI, homologous recombination occurs in E. coli while the original templates are removed via DpnI digestion in vivo, thus yielding clones harboring mutated circular plasmids. Nearly 100% efficiency was attained when this strategy was used to modify DNA sequences. 相似文献
110.
细胞核CaMK和Calcineurin 对大鼠心肌肥厚发生的作用 总被引:1,自引:0,他引:1
目的:研究大鼠心肌肥厚时,钙依赖的蛋白激酶和蛋白磷酸酶在心肌细胞膜、细胞浆和细胞核的分布规律,以探讨核钙信号与核反应在心肌肥厚发生过程中的病理生理意义.方法:制备腹主动脉缩窄大鼠心肌肥厚模型,同位素32P掺入法分别测定心肌细胞核、细胞浆和细胞膜的蛋白激酶活性及用无机磷生成显色法测定其蛋白磷酸酶活性.结果:腹主动脉缩窄术后4周大鼠心肌显著肥厚,伴有明显的血液动力学异常.与正常对照组相比较,腹主动脉缩窄心肌肥厚组心肌细胞核钙调素蛋白激酶(CaMK)活性增加101.1%(P<0.01),其膜的酶活性升高40.2%(P<0.01),而胞浆的酶活性不变(P>0.05);心肌细胞核钙调神经磷酸酶(Calcineurin)活性增加43.6%(P<0.05),膜和胞浆中其活性增加无显著性(P>0.05).正常组和腹主动脉缩窄心肌肥厚组心肌细胞CaMK和Calcineurin活性分布为核>膜>胞浆(P<0.01).结论:腹主动脉缩窄心肌肥厚时核内钙依赖的CaMK和Calcineurin活性增加,提示压力超负荷时细胞核内钙调节的蛋白磷酸化和去磷酸化水平增高,可能在介导心肌肥厚的发生中起重要作用. 相似文献