食管癌组织中Krüppel-like Factor4表达与术后复发转移的相关性

目的探究食管癌组织中Krüppel-like Factor4表达与术后复发转移的相关性。方法选取食管癌患者160例并收集其临床资料。采取免疫组化法检测Krüppel-like Factor4表达,根据患者术后是否复发转移将其分为复发转移组和无复发转移组,对比Krüppel-like Factor 4表达水平,并采用多因素logistic回归分析食管癌切除术患者术后复发转移的危险因素。结果Krüppel-like Factor4蛋白表达与分化程度、临床分期和淋巴结转移等临床病理参数显著相关(P<0.05),与患者的年龄、性别、肿瘤直径均无相关性(P>0.05)。复发转移组术后Krüppel-like Factor4阳性表达率显著低于未复发转移组,差异有统计学意义(P<0.05)。多因素分析显示,Krüppel-like Factor4(OR=2.012,P<0.001)是食管癌术后发生复发转移的独立影响因素。结论食管癌组织中Krüppel-like Factor4表达与患者术后复发转移具有相关性,其对患者术后复发转移具有重要预测价值。

Krüppel-like factor 4慢病毒表达载体构建及其对胃癌细胞BGC-823生物学行为的影响

目的构建Krüppel-like factor4(KLF4)过表达慢病毒载体,探讨其对胃癌细胞株BGC-823生物学行为的影响。方法检测BGC-823中KLF4 mRNA的表达水平;用真核表达质粒pcDNA3.1IE-KLF4-EGFP,将KLF4基因连入慢病毒载体pLv-UbC-IRES2-EGFP中,构建pLv-KLF4-IRES2-EGFP重组慢病毒表达载体。将酶切和测序鉴定后的重组质粒转染至BGC-823中,观察转染情况,RT-PCR检测KLF4 mRNA。慢病毒包装后转染BGC-823细胞,Western印迹检测KLF4蛋白。结果重组质粒经酶切和DNA测序证实目的基因插入正确;pcDNA3.1IE-KLF4-EGFP转染BGC-823细胞后KLF4 mRNA升高。慢病毒包装后转染BGC-823检测到目的蛋白KLF4。KLF4能够将细胞阻滞于G1/S,抑制其生长、促进细胞凋亡,减少细胞侵袭能力。结论转染BGC-823后KLF4蛋白检测证实慢病毒载体成功构建,KLF4能抑制胃癌细胞的恶性转化。

Krüppel-like factor 8 overexpression is correlated with angiogenesis and poor prognosis in gastric cancer

AIM:To investigate Krüppel-like factor 8 (KLF8) expression in gastric cancer and its relationship with angiogenesis and prognosis of gastric cancer. METHODS:One hundred and fifty-four patients with gastric cancer who underwent successful curative resection were retrospectively enrolled in the study. Fifty tumor-adjacent healthy gastric tissues (≥ 5 cm from the tumor margin) obtained during the original resection were randomly selected for comparative analysis. In situ expression of KLF8 and CD34 proteins were examined by immunohistochemistry. The intratumoral microvessel density (MVD) was determined by manually counting the immunostained CD34-positive endothelial cells in three consecutive high-magnification fields (× 200). The relationship between differential KLF8 expression and MVD was assessed using Spearman's correlation coefficient test. χ2 test was performed to evaluate the effects of differential KLF8 expression on clinicopathologic factors. Kaplan-Meier and multivariate Cox survival analyses were used to assess the prognostic value of differential KLF8 expression in gastric cancer. RESULTS:Significantly higher levels of KLF8 protein were detected in gastric cancer tissues than in the adjacent non-cancerous tissues (54.5% vs 34.0%, P < 0.05). KLF8 expression was associated with tumor size (P < 0.001), local invasion (P = 0.005), regional lymph node metastasis (P = 0.029), distant metastasis (P = 0.023), and tumor node metastasis (TNM) stage (P = 0.002), as well as the MVD (r = 0.392, P < 0.001). Patients with KLF8 positive expression had poorer overall survival (P < 0.001) and cancer-specific survival (P < 0.001) than those with negative expression. Multivariate analysis demonstrated that KLF8 expression independently affected both overall and cancer-specific survival of gastric cancer patients (P = 0.035 and 0.042, respectively). CONCLUSION:KLF8 is closely associated with gastric tumor progression, angiogenesis and poor prognosis, suggesting it may represent a novel prognostic biomarker and therapeutic target for gastric cancer.

Correlation of Krüppel-like factor 9 expression in pancreatic cancer tissue with serum tumor markers and focal cell invasion

Objective:To study the correlation of Krüppel-like factor 9 (KLF9) expressions in pancreatic cancer tissue with serum tumor markers and focal cell invasion.Methods: A total of 58 patients with pancreatic cancer treated in our hospital between June 2012 and May 2016 were collected, the expression of KLF9 in pancreatic cancer tissues and paracancerous tissues were measured and then patients were further divided into high KLF9 expression group and low KLF9 expression group, 29 cases in each group. Serum tumor marker levels as well as invasion gene and tumor suppressor gene expression in tumor tissue were compared between patients with different KLF9 expression.Results: KLF9 expression in pancreatic cancer tissue was significantly lower than that in paracancerous tissue;serum tumor markers CA19-9, CA242, CA50 and CEA levels of low KLF9 expression group were higher than those of high KLF9 expression group;focal invasion genes DKK-1, GSK3β and HOXB7 mRNA expression of low KLF9 expression group were higher than those of high KLF9 expression group while tumor suppressor genes Bach2, SIRT3, DPC4 and Kiss-1 mRNA expression were lower than those of high KLF9 expression group.Conclusion: The expression of KLF9 decreases in pancreatic cancer tissues, and the expression of KLF9 is negatively correlated with the malignant degree of tumor.

Krüppel-like factor 8 is a potential prognostic factor for pancreatic cancer

Background Pancreatic cancer is a lethal disease that is often diagnosed at an advanced stage.There is a lack of information to predict the prognosis of pancreatic cancer.Krüppel-like factor （KLF） 8 has been found to be deregulated in multiple cancers,and its high expression was correlated with poor prognosis.However,so far,no information was reported about the expression of KLF8 in pancreatic cancer.In the present study,we investigated,possibly for the first time,the expression of KLF8 in pancreatic cancer samples and analyzed its correlation with clinical parameters and overall survival （OS） rate.Methods We used immunohistochemical staining to detect KLF8 in 68 samples from patients who underwent surgery and its correlation with the clinicopathological characteristics.We used Kaplan-Meier curve to analyze the relationship between KLF8 expression and the OS time.Univariate analysis was performed in addition to multivariate hazard models with clinicopathological features to assess KLF8 as an independent prognostic factor.Results KLF8 was present in the cytoplasm of pancreatic cancer cells and 52.9％ of the 68 cases had positive expression.KLF8 expression was not associated with sex,age,tumor location,lymph node stage,and metastasis stage,but was associated with tumor stage （P=0.04）.Kaplan-Meier method demonstrated that patients with negative expression of KLF8 had a better prognosis.In univariate and multivariate models,KLF8 was a significant predictor of OS in pancreatic cancer.Conclusion Our results revealed that KLF8 may be a potential prognostic factor for pancreatic cancer.

Current knowledge of Krüppel-like factor 5 and vascular remodeling: providing insights for therapeutic strategies

Vascular remodeling is a pathological basis of various disorders. Therefore, it is necessary to understand the occurrence, prevention, and treatment of vascular remodeling. Krüppel-like factor 5 (KLF5) has been identified as a significant factor in cardiovascular diseases during the last two decades. This review provides a mechanism network of function and regulation of KLF5 in vascular remodeling based on newly published data and gives a summary of its potential therapeutic applications. KLF5 modulates numerous biological processes, which play essential parts in the development of vascular remodeling, such as cell proliferation, phenotype switch, extracellular matrix deposition, inflammation, and angiogenesis by altering downstream genes and signaling pathways. Considering its essential functions, KLF5 could be developed as a potent therapeutic target in vascular disorders.

Loss of the Krüppel-like factor 4 tumor suppressor is associated with epithelial-mesenchymal transition in colorectal cancer

Aim: Colorectal cancer (CRC) is the third leading cancer-related cause of death due to its propensity to metastasize. Epithelial-mesenchymal transition (EMT) is a multistep process important for invasion and metastasis of CRC. Krüppel-like factor 4 (KLF4) is a zinc finger transcription factor highly expressed in differentiated cells of the intestinal epithelium. KLF4 has been shown to play a tumor suppressor role during CRC tumorigenesis - its loss accelerates development and progression of cancer. The present study examined the relationship between KLF4 and markers of EMT in CRC. Methods: Immunofluorescence staining for KLF4 and EMT markers was performed on archived patient samples after colorectal cancer resection and on colonic tissues of mice with colitis-associated cancer. Results: We found that KLF4 expression is lost in tumor sections obtained from CRC patients and in those of mouse colon following azoxymethane and dextran sodium sulfate (AOM/DSS) treatment when compared to their respective normal appearing mucosa. Importantly, in CRC patient tumor sections, we observed a negative correlation between KLF4 levels and mesenchymal markers including TWIST, β-catenin, claudin-1, N-cadherin, and ;vimentin. Similarly, in tumor tissues from AOM/DSS-treated mice, KLF4 levels were negatively correlated with mesenchymal markers including SNAI2, β-catenin, and vimentin and positively correlated with the epithelial marker E-cadherin. Conclusion: These findings suggest that the loss of KLF4 expression is a potentially significant indicator of EMT in CRC.

Genetic Predisposition for Type 2 Diabetes Mellitus in a Cameroonian Population: Contribution of rs4731702 (C/T) Polymorphism of Krüppel-Like Factor 14 Gene

Introduction: Krüppel Like Factor 14 (KLF14) gene has recently been identified as a master gene for multiple metabolic phenotypes. The aim of the research study was to investigate the relationship between KLF14 rs4731702 (C/T) gene polymorphism with Type 2 Diabetes Mellitus (T2DM) in a Cameroonian population. Patients and Methods: This case-control study was conducted in 85 patients with T2DM and 95 healthy normoglycemic controls. All were nonrelated, of Cameroonian origin, and were adults aged 24 years old and above. Demographic, clinical and biological data were collected, and biochemical explorations were performed using enzymatic colorimetric methods. The genotyping of KLF14 rs4731702 (CT) gene polymorphism was done by the Polymerase Chain Reaction and Restriction Fragment Length Polymorphism. Results: In comparing the Cameroonian population that consisted of 85 patients with T2DM and 95 healthy controls, the minor or risk allele of the rs4731702 (C/T) polymorphism of the KLF14 gene was T (63.53% diabetic patients vs. 26.32% healthy controls, OR = 4.877 and p < 0.0001) while the protective allele was C (36.47% diabetic patients vs. 73.68% healthy controls, OR = 0.205 and p < 0.0001). The susceptibility to T2DM was higher among subjects having the CT and TT genotypes with OR = 2.721 and p = 0.0145) and OR = 3.907 and p < 0.0001) respectively. This gene polymorphism was not preferentially associated with a specific diabetes phenotype. Conclusion: This study has demonstrated for the first time the relationship between the KLF14 rs4731702 (C/T) gene polymorphism and T2DM in this Cameroonian population. This gene polymorphism could be a promising target for personalized medicine through the development of clinical genetic testing.

静态法和动态法评价活性炭分离低浓度Xe和Kr的性能

为获得高比活度的Xe测量源,开展了常温常压下CF-1450活性炭分离低浓度Xe和Kr的研究。利用液氮温度下N2的吸附脱附测试对CF-1450活性炭的孔结构进行了表征。结果表明,CF-1450活性炭的BET比表面积为1680 m^(2)/g,孔径分布以微孔为主。采用静态吸附法和混合气体动态吸附-脱附法研究了CF-1450活性炭常温常压下分离低浓度Xe和Kr的性能。在25℃时,CF-1450活性炭的Xe静态吸附容量为3.25 mmol/g,Kr静态吸附容量为1.30 mmol/g;Xe亨利系数为0.21 mmol/(g·kPa),Kr亨利系数为0.02 mmol/(g·kPa),Xe/Kr亨利选择性为10.5。在低压下,利用IAST法计算的Xe/Kr吸附选择性(y(Xe)∶y(Kr)=50∶50,y为混合气体中Xe、Kr的摩尔分数)为10.6。CF-1450活性炭对Xe和Kr的零点等量吸附热分别为35.7 kJ/mol和13.9 kJ/mol。基于CF-1450活性炭动态吸附分离和动态脱附分离低浓度Xe和Kr的研究结果,建立了常温常压下动态吸附-脱附法分离低浓度Xe和Kr的工艺流程,Xe回收率为79%,Kr去污因子为195。

首钢京唐KR热态脱硫渣重复利用的应用

以京唐KR热态脱硫渣重复利用项目为依托,对KR热态脱硫渣重复利用技术及设备进行研究,开发出具有自主知识产权的KR热态脱硫渣重复利用装置,并成功应用于实际生产,取得了良好的应用效果。

熔融制样-X射线荧光光谱法测定KR脱硫剂中氧化钙、氧化镁和二氧化硅含量的研究

目前对于KR脱硫剂中氧化钙、氧化镁和二氧化硅含量的测定采用络合滴定法和分光光度法进行分析。上述方法存在周期较长、操作繁琐、检测过程须接触危险化学品、产生废液等缺点。采用灼烧减量、熔融制样,X射线荧光光谱法测定KR脱硫剂中氧化钙、氧化镁和二氧化硅含量简单快速、具有较好的精密度、准确度,缩短了检验周期,大幅提高了检验效率。

血清Krüppel样因子2和血管紧张素Ⅱ受体样1内源性配体13对血液透析患者自体动静脉内瘘狭窄的预测价值

目的探讨血清Krüppel样因子2(KLF2)、血管紧张素Ⅱ受体样1内源性配体13(Apelin-13)水平对血液透析患者自体动静脉内瘘(AVF)狭窄的预测价值。方法选取2018年6月至2022年12月山东省济南市人民医院收治的214例以AVF为血管通路的血液透析患者为血液透析组,另选取同期53例体检健康者为对照组。血液透析组患者根据是否伴有AVF狭窄分为狭窄组(37例)和非狭窄组(177例)。记录患者临床资料,采用酶联免疫吸附试验法检测血清KLF2、Apelin-13水平。通过多因素Logistic回归方法分析血液透析患者AVF狭窄的影响因素,采用受试者工作特征(ROC)曲线分析血清KLF2、Apelin-13水平对血液透析患者AVF狭窄的预测价值。结果血液透析组血清KLF2、Apelin-13水平均低于对照组(均P<0.001)。狭窄组年龄、透析龄、透析中低血压比例、超滤率、低密度脂蛋白胆固醇水平均大于/长于/高于非狭窄组,体重指数、收缩压、KLF2、Apelin-13水平均低于非狭窄组(均P<0.05)。多因素Logistic回归分析结果显示,透析龄延长、透析中低血压、超滤率增加为血液透析患者AVF狭窄的独立危险因素,体重指数增加、KLF2升高、Apelin-13升高为独立保护因素(均P<0.05)。ROC曲线分析结果显示,血清KLF2、Apelin-13单独与联合预测血液透析患者AVF狭窄的曲线下面积分别为0.797、0.794、0.907,敏感度分别为54.05%、100.00%、91.89%,特异度分别为92.66%、50.85%、83.05%。结论血清KLF2、Apelin-13水平降低与血液透析患者AVF狭窄密切相关,可作为AVF狭窄的辅助预测指标。

Krüppel样转录因子8与乳腺癌他莫昔芬耐药的相关性

目的:探讨Krüppel样转录因子8(KLF8)与乳腺癌他莫昔芬(TAM)耐药及预后的相关性。方法:利用公共数据库分析KLF8 mRNA在TAM敏感与耐药细胞中的表达差异及KLF8 mRNA对接受TAM治疗乳腺癌患者预后的影响。运用RT-PCR及Western印迹方法检测MCF-7与LCC2细胞中KLF8 mRNA及蛋白表达差异,免疫组化检测97例Luminal A/B亚型接受TAM治疗乳腺癌中KLF8表达情况并分析其与预后的关系,运用CCK-8试剂盒检测沉默及过表达KLF8后在不同浓度TAM作用下细胞增殖变化。结果:TAM耐药细胞中KLF8表达水平高于TAM敏感细胞,接受TAM治疗Luminal A/B亚型乳腺癌患者中,KLF8高表达者预后差,过表达KLF8后细胞对TAM耐药性增强,而沉默KLF8后细胞对TAM耐药性减弱。结论:KLF8高表达与乳腺癌TAM耐药正相关,在Luminal A/B亚型的乳腺癌中,KLF8高表达TAM治疗效果差,KLF8或可成为TAM疗效判断及逆转耐药的新靶点。

Krüppel样因子4通过支持PPARγ信号通路维持细胞稳态以保护血管平滑肌细胞免受泡沫细胞样表型转化的损害

动脉粥样硬化(AS)被普遍认为是一种血管壁细胞(包括内皮细胞和血管平滑肌细胞)、循环细胞以及固有免疫原性细胞(例如单核细胞/巨噬细胞)等多种细胞综合作用引起的炎症性疾病。其中血管平滑肌细胞(VSMCs)胆固醇超负荷形成的泡沫细胞可能在动脉粥样硬化的进展中发挥重要作用。Krüppel样因子4(KLF4)是一种关键的抗炎转录因子,尤其在心血管疾病方面,已被证实发挥了重要的血管功能保护作用。然而,目前尚不清楚KLF4是否在AS过程胆固醇对VSMCs的损伤中发挥保护作用。该研究旨在探讨KLF4在AS进展过程中VSMCs泡沫细胞样表型转化的作用及其分子机制。小鼠AS造模结果显示,KLF4缺失增加动脉粥样硬化斑块面积(P<0.05),并增加动脉壁脂质蓄积(P<0.05)及血清胆固醇含量(P<0.05),加速AS进展。细胞内油红O染色及胆固醇含量测定研究证实,KLF4缺失促进VSMCs内胆固醇蓄积(P<0.05)。QRT-PCR和Western印迹结果证实,KLF4缺失促进VSMCs胆固醇摄取、合成、促炎因子分泌及巨噬细胞黏附和胆固醇损伤诱导的巨噬细胞标志物的表达(P<0.05),抑制胆固醇流出和氧化相关基因及收缩表型标志物的表达(P<0.05),加速VSMCs源性泡沫细胞形成。KLF4敲除VSMCs中利用腺病毒Ad-GFP-KLF4补救表达KLF4,显著逆转上述改变,并阻断由胆固醇蓄积诱导的TLR4-MyD88-p65通路的激活。随后,siRNA诱导的过氧化物酶体增殖物激活受体γ(PPARγ)的选择性基因消融消除了KLF4的这些作用。总之,我们的研究结果提示,KLF4通过激活PPARγ途径,抑制胆固醇摄取和合成,加速胆固醇流出,同时抑制促炎因子分泌、巨噬细胞黏附和胆固醇损伤诱导的巨噬细胞标志物表达,从而在VSMCs中实现对胆固醇刺激的保护作用。

首钢水钢含钒钛铁水KR脱硫预处理实践

KR铁水脱硫工艺由于其优秀的搅拌脱硫效果使其得到不断地推广应用.首钢水钢建立两座KR脱硫站进行含钒钛铁水脱硫预处理,铁水脱硫站设备设计处理产能为316.8万t/年.为了探索高效脱硫的工艺过程,制定低成本运行工艺制度.在分析KR脱硫过程机理的基础上,结合对钒钛铁水性质、脱硫剂粒度及成分、搅拌转速、搅拌时间等分析影响脱硫的主要因素,有针对性地提出设计方案和控制措施,为低成本KR脱硫生产提供指导和借鉴.

KR铁水预处理脱硫的动力学模型

利用FactSage软件建立机械搅拌条件下铁水预处理脱硫的动力学模型,研究硫在铁水中的扩散过程及铁水与脱硫剂颗粒在界面处的反应。计算结果与实验结果基本吻合,表明该模型可用于预测不同温度、化学成分、转速和脱硫剂添加量下的脱硫速率和成本。建议在搅拌转速为80-120 r/min、较高温度为1573-1673 K、较小的脱硫剂粒径为2.5-1.5 um、大的脱硫剂添加量为0.35-0.64 kg/t的条件下,提高脱硫速率。此外,为综合提高脱硫效率并降低成本,计算了不同脱硫剂添加量和脱硫时间在脱硫过程中的S含量和成本控制。通过对添加脱硫剂、耐火材料侵蚀和电耗的成本数据分析,将铁水预处理脱硫总成本与时间步长(Δt)拟合为Costtotal=0.066+1.58x10^(-7)o·Δt。结果表明较少的脱硫剂添加量和较长的脱硫时间有助于降低成本,而更多的脱硫剂添加量有利于提高脱硫效率。

基于Kmeans–BP神经网络的KR工序终点铁水硫含量预测模型

针对KR工序终点铁水硫含量预测问题,提出一种基于Kmeans聚类分析和BP神经网络(BPNN)相结合的建模方法.首先,通过Kmeans聚类对KR工序生产数据进行模式识别和分类,构建不同工况特征的数据集;然后,基于BP神经网络,针对不同数据集训练预测模型;最后,将不同数据集的预测模型进行集成,形成最终的终点铁水硫含量预测模型,实现对不同铁水条件和工况条件的预测.利用某钢铁企业实际生产数据,分别用基于脱硫反应动力学、BP神经网络和Kmeans-BPNN方法建立的预测模型,对KR工序终点铁水硫含量进行预测.结果表明,Kmeans-BPNN的KR工序终点硫含量预测模型的精度显著高于脱硫反应动力学和BP神经网络的预测模型.

腺苷A2a受体/Krüppel样因子5对缺血再灌注损伤大鼠心肌的影响

目的:探讨腺苷A2a受体/Krüppel样因子5(KLF5)对缺血再灌注损伤大鼠心肌的影响。方法:42只250~300 g雄性SD大鼠随机分为4组:假手术组(Sham组,n=6)、缺血再灌注组(I/R组,n=12)、缺血再灌注+腺苷A2a受体特异性激动剂CGS21680组(I/R+CGS组,n=12)、缺血再灌注+腺苷A2a受体拮抗剂ZM241385组(I/R+ZM组,n=12)。采用结扎左冠状动脉前降支再灌注的方法制备大鼠心肌缺血再灌注损伤模型。I/R+CGS组于再灌注前5 min静脉注射CGS21680后持续泵注60 min,CGS+ZM组于再灌注前5 min静脉注射ZM241385。于造模前,缺血5 min,再灌注10 min、45 min及120 min时分别记录各组大鼠的心率(HR)、平均动脉压(MAP)以及心率与收缩压乘积(RPP)。再灌注结束后取血液,酶联免疫吸附测定法检测血清心肌钙蛋白I(c TnI)和成纤维细胞生长因子21(FGF21)水平。再灌注结束后再次结扎左冠状动脉前降支,采用TTC染色法确定心肌梗死面积。处死大鼠,采用Western blot法检测缺血区心肌组织中的肿瘤坏死因子-α(TNF-α)、白细胞介素(IL)-1β和KLF5的蛋白表达水平。结果:各组造模前、Sham组各时间点HR、MAP及RPP差异无统计学意义。与Sham组比较,I/R组缺血5 min时HR、MAP及RPP降低;与I/R组比较,I/R+CGS组再灌注10 min和45 min时HR、MAP及RPP降低,I/R+ZM组再灌注10 min和45 min时HR、MAP及RPP升高(P均<0.05)。与Sham组比较,I/R组心肌梗死面积增大,血清cTnI水平升高,FGF21水平降低;与I/R组比较,I/R+CGS组心肌梗死面积减小,血清cTnI水平降低,FGF21水平升高,I/R+ZM组心肌梗死面积增大,血清c TnI水平升高,FGF21水平降低(P均<0.05)。与Sham组比较,I/R组心肌组织中TNF-α、IL-1β和KLF5的蛋白表达水平均明显升高;与I/R组相比,I/R+CGS组心肌组织中TNF-α、IL-1β和KLF5的蛋白表达水平均明显降低,I/R+ZM组心肌组织中TNF-α、IL-1β和KLF5的蛋白表达水平均明显升高(P均<0.05)。结论:激活腺苷A2a受体可抑制缺血心肌细胞中KLF5表达,降低心肌梗死再灌注损伤程度,缓解心肌细胞缺氧状态,促进心肌细胞损伤后修复,对缺血再灌注损伤大鼠心肌起保护作用。

昆虫Kr-h1基因的生物信息学分析

Kr-h1基因是研究昆虫变态发育与害虫生物防治的重要靶标分子。本研究解析了昆虫Kr-h1基因结构、保守结构域、二级结构与三级结构,开展了多序列比对、表达模式分析与系统发育树重构。结果表明,Kr-h1基因外显子数量较为保守,多为2个,而内含子长度变异较大。Kr-h1蛋白一般含8个锌指结构,二维与三维结构显示锌指结构保障了蛋白的稳定性。基于全长序列的系统发育分析显示,昆虫Kr-h1为直系同源,亲缘关系与物种进化相吻合,基于锌指结构的系统发育则显示Kr-h1不同模块进化中的差异。菜粉蝶转录组数据显示,该基因表达模式与变态密切相关。本研究丰富了昆虫Kr-h1基因的知识,以期为菜粉蝶、西花蓟马等昆虫变态发育研究与生物防治提供新策略。

海洋链霉菌KR结构域基因的克隆与分析

酮还原酶(Ketoreductase,KR)是聚酮合酶(Polyketide Synthase,PKS)重要的组分,可催化β-酮基的还原,是手性药物合成的重要手段,并在聚酮化合物合成中起着关键性作用。该研究从海洋链霉菌Streptomyces sp.X-66基因组DNA扩增出一条1331 bp的KR结构域基因,并进行生物信息学分析。Blast结果显示该序列包括了FAS KR和PKS KR两部分,核心功能区域集中于PKS KR基因部分序列;最大ORF区域拟编码333个氨基酸,理论等电点为4.80,分子式为C1500H2419N433O463S6,不稳定指数为24.85,为酸性稳定蛋白,并有较低亲水性,不含信号肽和跨膜结构,二级结构以α-螺旋和无规卷曲为主,SDS-PAGE显示其相对分子质量约为70 ku。通过氨基酸多序列比对,表明蛋白KR3属于B1型KR;以蛋白KR3氨基酸序列预测并检验其三级结构模型,利用分子对接和可视化分析预测蛋白KR3与配体结合的关键残基为^(204)Thr、^(206)Thr和^(207)Leu,依据相关研究分析蛋白KR3引导底物进入活性中心的结合模式与B型KR较为符合,为进一步研究KR3的功能及新型手性药物和聚酮化合物的合成提供科学依据。