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排序方式: 共有63条查询结果,搜索用时 62 毫秒
1.
细菌耐药拮抗剂的研究   总被引:6,自引:1,他引:5  
本文介绍了具有拮抗细菌耐药性作用的物质的研究进展情况,包括灭活酶抑制剂、药物渗透促进剂、外输泵抑制剂、细菌生物被膜抑制剂、抗菌药物增强剂、耐药质粒消除剂等。  相似文献   
2.
Oxidative stress can induce apoptosis of granulosa cells and lead to follicular atresia, thereby reducing the number of pigs giving birth. The aim of this study was to investigate the protective effect of Periplaneta americana peptide (PAP) on the apoptosis of the granulosa cells of pig ovaries (PGCs) induced by hydrogen peroxide (H2O2) via FoxO1. PGCs were treated with H2O2 to establish a cell apoptosis model. Cell viability was measured using the cell counting kit-8 (CCK-8) assay, and cell apoptosis was detected using flow cytometry. The malondialdehyde (MDA) level and nitric oxide (NO) content were detected to reflect the oxidative stress. Western blotting, qRT-PCR and overexpression were undertaken to determine the expression of FoxO1 and caspase-3, and immunofluorescence was used to detect FoxO1 in the nucleus and cytoplasm. PGCs were treated with 100 μM H2O2 for 6 hr, which resulted in oxidative damage and apoptosis and an apoptosis rate for PGCs of 32.95%. Next, PGCs were treated with 400 μg/ml PAP for 24 hr to repair the apoptosis induced by H2O2. PAP improved cell viability in H2O2-stimulated PGCs, the increased MDA level and NO content caused by H2O2 stimulation were reversed and the apoptotic rate of PGCs was reduced. The qRT-PCR and Western blotting results indicated that PAP decreased the H2O2-induced apoptosis and the expression of FoxO1 and caspase-3 in PGCs. The effect of PAP was the same following FoxO1 overexpression. FoxO1 was expressed in the nucleus when stimulated by H2O2 or overexpression; however, it migrated to the cytoplasm following PAP treatment. PAP decreased the apoptosis of PGCs induced by H2O2 by regulating FoxO1 expression and nuclear translocation.  相似文献   
3.
作者介绍了具有颉颃细菌耐药性作用的物质的研究应用进展情况,包括灭活酶抑制剂、药物渗透促进剂、外输泵抑制剂、细菌生物被膜抑制剂、抗菌药物增强剂、耐药质粒消除剂等。  相似文献   
4.
杨先乐  夏春  左文功 《水产学报》1989,13(2):138-144
本文比较了疫苗株FR—854和FR—836—w的免疫原性,及其对三寸左右草鱼种的有效免疫剂量。疫苗株FR—854和FR—836—w均有较强的免疫原性,其保护力可达70%以上。但试验结果初步证明,FR—854疫苗比FR—836—w疫苗免疫原性更强。经统计分析,FR—854疫苗的免疫保护力可达88.9±12.0(6)%,血清中和抗体效价为160.5±58.9(6);而FR-838-W疫苗分别只有71.3±14.2(6)%、88.3±26.2(6);二者有显著的差异(0.05>P>0.01)。注射免疫三寸左右的草鱼种,FR—854的免疫剂量在3—5×10~(4.5)TCID_(50)/尾左右,FR—836—w在3—5×10~(7.5)TCID_(50)/尾左右,其免疫保护力可达80%左右,同时我们测得ER—854的半数免疫量为10~(5.1)TCID_(50)/ml。  相似文献   
5.
分析了非线性控制中经常使用的无源稳定性定理.介绍了模糊PID控制器的构造、实现以及与传统PID控制器的关系.将无源稳定性定理应用到传统PID控制器稳定性分析中,推导出PID控制参数的要求.最后利用模糊PID控制器与传统PID控制器的联系,进一步推算出符合稳定性要求的模糊PID控制器设计规则.给出具体实例,验证模糊PID系统稳定的参数范围.  相似文献   
6.
The aim of this study was to explore the expression difference of miRNAs and mRNAs between the follicular phase (FP) and luteal phase (LP) in porcine ovaries and provide a theoretical basis for the research on mammalian reproductive regulation. RNA‐Seq and miRNA‐Seq were used to identify differentially expressed genes (DEGs) and miRNAs (DEMs) between the FP and LP in ovaries of six sows (3‐year‐old Yorkshire pigs with similar weights and same parities). Bioinformatic analysis was used to screen potential genes and miRNAs related to porcine ovarian function. Real‐time qualitative PCR was used to validate the sequencing results. RNA‐Seq results showed that 3,078 genes were up‐regulated, and 1,444 genes were down‐regulated in the LP compared with the FP, and DEGs were significantly enriched in 242 Gene Ontology (GO) terms and 33 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. miRNA‐Seq identified 112 DEMs, of which 25 were up‐regulated and 87 were down‐regulated in the LP compared with the FP. We obtained 186 intersection genes (IGs) between the 4,522 DEGs and 2,444 target genes predicted from the 112 DEMs. After constructing a miRNA‐gene‐pathway network, we identified key miRNAs and genes including miR‐17‐3p, miR‐214, miR‐221‐5p, miR‐125b, FGF1, YWHAG, YWHAZ, FDFT1 and DHCR24, which are enriched in Hippo and PI3K‐Akt signalling pathways, and various metabolic pathways. These results indicate that these key genes and miRNAs may play important roles in the developmental transition from FP to LP in porcine ovaries and represent candidate targets for further study.  相似文献   
7.
Cochliobolusmiyabeanus在75℃,相对湿度65%、70%、75%、80%、85%下和80℃,相对湿度55%、65%、70%、75%、80%下进行不同时间的杀菌试验.在此基础上,用固定温度,以相对湿度同杀菌时间建立回归关系,并用等差法建立杀菌时间模型和以焓增量建立湿热杀菌时间模型,并对两种方法进行了比较  相似文献   
8.
以鱼粉和豆粕为蛋白源,鱼油和大豆油为脂肪源,配制蛋白质水平分别为35%、40%、45%和脂肪水平分别为7%、9%、11%的二因子三水平的实验饲料,并以鲜杂鱼饲料为对照,对三疣梭子蟹(Portunus trituberculatus)(体质量36.5~42.9 g)进行为期20周的养殖实验,研究三疣梭子蟹对蛋白质、脂肪的需要量,以及对卵巢色素沉积的影响.养殖实验采用海区串笼吊养方式,每个吊笼放养1只雌蟹.实验共10个处理,每个处理18个蟹,3个重复.结果表明,不同蛋白质、脂肪水平饲料对三疣梭子蟹增重率(269.2%~404.90%)、饲料系数(2.01~2.55)、蛋白质效率(1.02%~1.29%)和肥满度(16.26%~23.97%)均有显著影响(P<0.05);增加饲料蛋白质和脂肪水平,可显著提高三疣梭子蟹生长,降低饲料系数(P<0.05).对照饲料组的三疣梭子蟹获得了最高的增重率(461.69%),但饲料系数也是最高(6.35),而且肥满度(21.15%)低于P40Lll组(蛋白质40%、脂肪11%组).三疣梭子蟹水分、肌肉蛋白、脂肪、灰份和卵巢灰份不受饲料蛋白质、脂肪水平变化的影响(P>0.05),但卵巢蛋白质、脂肪影响显著(P<0.05),而且高蛋白饲料组的卵巢脂肪含量总是显著低于其他各组.在同一饲料蛋白质水平下,9%脂肪饲料组的三疣梭子蟹卵巢类胡萝卜素总量、虾青素含量和成色比色值都显著高于其他各饲料组(P<0.05).与对照饲料组比较,实验饲料组的三疣梭子蟹卵巢类胡萝卜素总量和虾青素含量呈显著优势.综合考虑生长、饲料系数和色素沉积,三疣梭子蟹饲料的适宜蛋白质水平和脂肪水平分别为40%~45%和9%.本研究旨在为制定三疣梭子蟹饲料配方和改善其品质提供理论依据.  相似文献   
9.
利用子房离体培养的方法克服了甘蓝型油菜与青花菜杂种后代杂种胚的衰亡,并通过组织培养技术获得了杂交后代。试验结果表明:授粉后15d的子房离体培养效果最好,获得7粒饱满种籽,其中2粒发芽,发芽率为0.29;1/2MS+B5有机+IAA1.5mg/L+蔗糖50g/L为最佳的子房离体培养基,平均每个角果可得到杂种0.17粒,杂种发芽率可达66.7%;通过比较父母本和杂交后代性状,发现杂交后代的生物学性状偏向父本。  相似文献   
10.
The aim of this study is to determine the effects of iPPOV on pro-inflammatory and anti-inflammatory cytokine levels in rats. iPPOV (1 ml/rat) was administered intraperitoneal route to 49 rats, except for 7 rats (Control, 0 group). Serum samples were collected from 7 rats at 1st, 2nd, 4th, 8th, 12th, 16th and 24th hr after treatments. Levels of TNF-α, IL-6, IL-12 and IL-10 were determined using ELISA. Administration of iPPOV stimulated TNF-α (16th and 24th hr) and IL-6 (12th, 16th and 24th hr) synthesis and caused fluctuations in IL-10 and IL-12 concentrations. In conclusion, increased cytokine levels could be attributed to immunomodulatory activity of iPPOV, however, detailed studies are required to fully understand effects of iPPOV on immune system.  相似文献   
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