纳米Al_2O_3改性水性木器漆耐磨性和硬度的研究

为提高水性聚丙烯酸酯木器漆的耐磨性和硬度,进行纳米Al2O3浆料的制备及其对水性木器漆改性的研究,探讨分析不同制备方法和Al2O3添加量对漆膜耐磨性和硬度的影响。结果表明:以聚丙烯酰胺为分散剂、聚乙二醇和辛基酚聚氧乙烯醚为润湿剂、聚乙烯吡咯烷酮为稳定保护胶,在高速搅拌下制成的纳米Al2O3浆料,在透射电镜下观察发现纳米Al2O3颗粒分布均匀,具有良好的分散性;在不影响漆膜透明度的情况下,漆膜耐磨性和硬度随Al2O3添加量增加得到提高,添加量在1.5%时漆膜具有较好的耐磨性和硬度;纳米杂合工艺法的漆膜耐磨性和硬度优于后添加法制备的水性木器漆涂膜。     

高贵化回交育种技术在凉蔗2号遗传亲系中的应用探讨

凉蔗2号亲系广泛应用高贵化杂交育种方法,引入异质血缘多次回交,打破连锁遗传,重组有利基因,促进血缘多样化,实现超亲。进行凉蔗2号亲系遗传高贵化杂交技术研究,有利于为凉蔗2号用作广亲和力亲本,实施远缘杂交制种工作提供有益借鉴。     

单端孢霉烯族毒素生物脱毒技术研究进展

单端孢霉烯族毒素在粮食和饲料中污染严重,主要是T-2毒素和脱氧雪腐镰刀烯醇(DON)等,其毒性作用强,对人和动物产生严重危害。因此,单端孢霉烯族毒素的脱毒方式逐渐成为研究热点,尤其是生物脱毒。很多微生物被证实能够降解霉菌毒素,包括细菌、真菌和酵母菌,可将毒素降解成低毒或无毒的产物。论文以生物脱毒为出发点,从细菌、真菌和酵母菌三个角度概述了单端孢霉烯族毒素中T-2毒素和DON的脱毒研究现状,以期为后续开发并挖掘更加安全高效的生物脱毒方式提供参考。     

不同日龄滩羊皮肤组织化学特征比较

为比较2、35日龄滩羊皮肤毛囊的发育特点与血管内皮生长因子（vascular endothelial growth factor，VEGF）和血管内皮生长因子受体2（vascular endothelial growth factor receptor 2，VEGFR2）的分布特征，探究出生后滩羊被毛生长发育的变化特点，试验应用常规HE染色及改良Masson胶原纤维染色、Gomori银氨法染色、磷钨酸染色等特殊染色观察2与35日龄滩羊皮肤组织结构特点；应用免疫组织化学法结合免疫荧光染色法观察VEGF及VEGFR2在2与35日龄滩羊皮肤组织中的分布定位，并用IPP图像分析软件进行定量分析。结果显示：与2日龄滩羊皮肤组织比较，35日龄滩羊表皮与真皮间界限更加清晰，毛囊结构发育完整；毛囊密度显著降低（P<0.05）；胶原纤维与弹性纤维含量增加，形成网格状分布。免疫组化及免疫荧光结果显示，VEGF及VEGFR2在滩羊皮肤表皮及毛囊外根鞘、皮脂腺上均有表达。统计表明，VEGF及VEGFR2在2日龄滩羊皮肤组织中的表达量均显著高于35日龄（P<0.05）。综合上述结果，滩羊毛囊发育过程中，胶原纤维和弹性纤维增加明显；VEGF与VEGFR2通路在毛囊角质形成中起直接调节作用。     

氟对小鼠MC3T3-E成骨细胞内Ca~(2+),NO浓度的影响

为了探究不同浓度的氟化钠对小鼠MC3T3-E成骨细胞内Ca~(2+),NO浓度以及细胞凋亡的影响,建立细胞梯度染氟模型,获取MTT细胞增殖曲线;通过DAPI和HE染色观察细胞核及细胞形态学变化;运用荧光探针Fluo-3 AM和DAF-FM DA标记染氟成骨细胞,采用流式细胞仪测定成骨细胞内Ca~(2+),NO浓度变化。结果表明,随着氟浓度的增加,细胞形态异常,细胞增殖率降低,成骨细胞内Ca~(2+),NO的浓度增加,高氟长时间作用会使细胞生命活性降低,生理反应减弱或缺失,从而影响Ca~(2+),NO的浓度。试验证明,高氟通过增加细胞内Ca~(2+),NO的浓度抑制细胞增殖,诱导细胞凋亡。     

The Influence of Carbon Dioxide or Ozone Concentration on Growth and Assimilate Partitioning in Seedlings of Nine Conifers

Abstract

Seedlings of nine different conifers were exposed to 355 and 730 μmol mol-1 CO₂, or low (> 15 nmol mol^?1) and elevated 0₃ concentration (70 nmol mol^?1) for 81–116 days. The experiments were conducted in growth chambers placed in a greenhouse. Increased CO₂ concentration enhanced the mean relative growth rate (RGR) and total plant dry weight by 4 and 33% in Larix leptolepis, by 4 and 38% in Larix sibirica, by 7 and 47% in Picea glauca and by 3 and 16% in Picea sitchensis, respectively. The growth rates and dry weights of Pimis contorta, Pinus mugo and Pseudotsuga menziesii were not significantly affected. Carbon dioxide enrichment enhanced RGR of two provenances of Picea abies by 4 and 6%, respectively, while a third provenance was unaffected. In Pimis sylvestris, only the RGR of one of three provenances was stimulated by CO₂ enrichment (4%).

After two growth seasons CO₂ enrichment enhanced RGR and total plant dry weight by 11 and 35% in Picea abies and by 12 and 36% in Pinus sylvestris, respectively. Elevated CO₂ decreased the shoot:root ratio in Larix leptolepis, and decreased the needlerstem ratio in Picea glauca, but increased it in Pseudotsuga menziesii.

Elevated O₃ significantly decreased the plant dry weight in Picea sitchensis, Pseudotsuga menziesii and in one of three provenances of Pinus sylvestris, while the other species and provenances were unaffected. Increased O₃ concentration increased the shoot:root dry weight ratio in one of three Picea abies provenances, in all three Pinus sylvestris provenances and in Pinus contorta. The needle:stem ratio was enhanced by O₃ in seven of the nine species. The O₃ exposure caused chlorosis of needles in all species except Pseudotsuga menziesii.     

用2,4-D处理获得可育甘薯组种间杂种

用50mg/L 2,4-D处理杂交不亲和组合甘薯(Ipomoea batatas (L.)Lam.)品种徐薯18(2n＝6x＝90)×L.lacunosa(2n＝2x＝30)以及I.trifida(2n＝4x＝60)×L triloba(2n＝2x＝30)的母本花器,获得了可育种间杂种植株,并对种间杂种进行了过氧化物酶同工酶分析和细胞学观察.特别是徐薯18×I.lacunosa的杂种后代具有明显的结薯性,这是首次报道获得具有结薯性的甘薯品种和第Ⅱ群近缘野生种种间杂种.     

Seroprevalence,associated risk factors analysis and first molecular characterization of chlamydia abortus among Egyptian sheep

Chlamydia abortus is one of the most common abortive agents worldwide in sheep. Few studies have been reported C. abortus infection among sheep in Egypt but the available data is scarce. The objective of the present study was to determine the seroprevalence of C. abortus among sheep, the associated risk factors and its molecular characterization. The present study was conducted on 675 sheep in six Governorates at Northern Egypt. Data analysis confirmed the presence of antibodies against C. abortus in 93 out of 675 sheep. The logistic regression model was fitted to identify the associated risk factors with C. abortus infection. The results revealed that C. abortus increased significantly in ewes (OR = 4.04, 95 %CI: 1.44−11.28) during autumn season (OR = 3.6, 95 %CI: 1.64–8.28), in ewes with a history of abortion (OR = 1.4, 95 %CI: 0.87–2.50) and in farm where no lambing pen (OR = 2.2, 95 %CI: 1.30–3.94) or abscence of post abortion measures (OR = 1.96, 95%CI: 1.23-3.12). In addition, age, flock size and exchange of breeding ram had no significant effect on prevalence of chlamydiosis. Also, PCR assay was confirmed presence of C. abortus as accusative pathogen in aborted ewe and the genetic characterization of Egyptian C. abortus strain revealed 100 % identity with another strain from Iraq. A control program should be applied to reduce economic losses and risk of human infection.     

禽致病性大肠杆菌Hcp2b对雏鸡气管黏膜细胞因子-细胞因子受体相互作用通路的影响

T6SS （type VI secretion system）是革兰阴性菌中常见的一种分泌系统,其效应蛋白Hcp2b作用机制迄今仍未明晰。本研究以禽致病性大肠杆菌（avian pathogenic Escherichia coli,APEC） Hcp2b蛋白为研究主体,旨在探究Hcp2b蛋白在APEC感染鸡气管黏膜过程中发挥的作用及机制。采用Red重组方法以质粒pKD3为模板构建hcp2b缺失株,pSTV-28质粒连接hcp2b目的片段构建重组载体,导入感受态Δhcp2b菌株构建回复株,并对Δhcp2b菌株的生长曲线进行测定。7日龄雏鸡气管感染hcp2b缺失株及野生株,感染后12、24 h收集鸡气管黏膜细胞进行转录组学测序及生物信息学分析。结果表明,hcp2b缺失株及回复株构建成功,hcp2b基因缺失对菌株的生长性能无影响。hcp2b基因缺失株感染气管黏膜后,mRNA的表达谱发生变化,感染后12 h,有144个基因表达量发生变化（上调差异基因87个,下调57个）;感染后24 h,有135个基因表达量发生变化（上调差异基因79个,下调56个）。生物信息学分析发现差异基因富集在Cytokine-cytokine receptor interaction、Protein processing in endoplasmic reticulum等信号通路。hcp2b基因缺失未影响APEC的生长特性,hcp2b基因缺失后影响雏鸡气管黏膜Cytokine-cytokine receptor interaction通路基因mRNA转录水平的变化,IL-1β、IL-12b的表达均上调。该结果为APEC的致病机制研究提供了理论依据。     

5-Aza-dC对牛成肌细胞MyoD1启动子甲基化及mRNA表达的影响

旨在探究5-氮杂-2-脱氧胞苷（5-Aza-2’-deoxycytidine,5-Aza-dC）对牛成肌细胞的增殖和肌分化因子（myogenic differentiation 1,MyoD1）启动子甲基化以及mRNA表达的影响。本研究复苏了前期冻存的关岭牛成肌细胞,并进行培养,待其生长到对数生长期,再通过不同浓度的5-Aza-dC对牛成肌细胞进行处理,利用流式细胞仪检测细胞凋亡和周期;结合高通量检测方法检测MyoD1启动子甲基化水平,并利用qRT-PCR检测MyoD1及相关基因的表达水平。研究发现,0.1 μmol·L^-15-Aza-dC为最适浓度,该浓度下细胞抗凋亡因子Bcl的表达极显著降低（P<0.01）,促凋亡因子Bax的表达极显著提高（P<0.01）,促凋亡因子Caspase-9的表达显著提高（P<0.05）;周期因子Cyclin A2的表达显著提高（P<0.05）,而细胞因子Cyclin B1、Cyclin D的表达无显著变化;检测空白组和试验组MyoD1启动子甲基化水平发现,试验组甲基化水平极显著低于空白组（P<0.01）;而mRNA的表达水平极显著高于空白组（P<0.01）。5-Aza-dC能够通过改变Caspase-9、Bcl、Bax、Cyclin A2等基因的表达来调节关岭牛成肌细胞的增殖和凋亡,并能够有效降低MyoD1基因启动子的甲基化水平（P<0.01）;极显著提高其mRNA的表达量（P<0.01）。低浓度的5-Aza-dC能通过促进细胞凋亡及调控关岭牛MyoD1的甲基化水平来调控MyoD1的表达;同时推测,MyoD1基因启动子的甲基化水平能够影响关岭牛成肌细胞的生长发育,可为遗传标记辅助关岭牛的改良提供理论参考。