Constitutive expression of antimicrobial peptide PR-39 in transgenic mice significantly enhances resistance to bacterial infection and promotes growth

Use of huge amounts of antibiotics in farm animal production has promoted the prevalence of antibiotic-resistant bacteria, which poses a serious threat to public health. Therefore, alternative approaches are needed to reduce or replace antibiotic usage in the food animal industry. PR-39 is a pig-derived proline-rich antimicrobial peptide that has a broad spectrum of antibacterial activity and a low propensity for development of resistance by microorganisms. To test whether ubiquitous expression of PR-39 in transgenic (TG) mice can increase resistance against bacterial infection, we generated TG mice that ubiquitously express a pig-derived antimicrobial peptide PR-39 and analyzed their growth and resistance to infection of the highly pathogenic Actinobacillus pleuropneumoniae (APP) isolated from swine. The growth performance was significantly increased in TG mice compared with their wild-type (WT) littermates. After the APP challenge, TG mice exhibited a significantly higher survival rate and significantly lower tissue bacterial load than WT littermates. Furthermore, the tissue lesion severity that resulted from APP infection was milder in TG mice than that in their WT littermates. This study provides a good foundation for the development of PR-39-expressing TG animals, which could reduce the use of antibiotics in the farm animal industry.     

绿道及其研究进展

20世纪90年代以来,绿道一直是保护生物学、景观生态学、城市规划和景观设计等多个学科交叉的研究热点和前沿,这种热潮被称为绿道运动.在对绿道的概念进行分析的基础上,探讨了绿道的发展及其主要阶段.分析了绿道的生态功能、休闲游憩功能、经济发展功能、社会文化和美学功能.探讨了绿道规划的方法,及绿道设计的5个方面：绿道宽度的设计、绿道与居住地的距离、绿道与机动车的交叉设计、绿道的路面和配套设施设计、绿道设计的人文关怀.最后回顾了绿道在国内的理论研究和实践进展,分析了绿道对我国自然保护、城市绿地系统和开放空间、文化遗产保护、旅游休闲等方面的启示.     

Subcellular localization and functional analyses of a PR10 protein gene from Vitis pseudoreticulata in response to Plasmopara viticola infection

Downy mildew, caused by the oomycete Plasmopara viticola, is a serious fungal disease in the cultivated European grapevines (Vitis vinifera L.). The class 10 of pathogenesis-related (PR) genes in grapevine leaves was reported to be accumulated at mRNA level in response to P. viticola infection. To elucidate the functional roles of PR10 genes during plant–pathogen interactions, a PR10 gene from a fungal-resistant accession of Chinese wild Vitis pseudoreticulata (designated VpPR10.2) was isolated and showed high homology to PR10.2 from susceptible V. vinifera (designated VvPR10.2). Comparative analysis displayed that there were significant differences in the patterns of gene expression between the PR10 genes from the two host species. VpPR10.2 was induced with high level in leaves infected by P. viticola, while VvPR10.2 showed a low response to this inoculation. Recombinant VpPR10.2 protein showed DNase activity against host genomic DNA and RNase activity against yeast total RNA in vitro. Meanwhile, recombinant VpPR10.2 protein inhibited the growth of tobacco fungus Alternaria alternata and over-expression of VpPR10.2 in susceptible V. vinifera enhanced the host resistance to P. viticola. The results from subcellular localization analysis showed that VpPR10.2 proteins were distributed dynamically inside or outside of host cell. Moreover, they were found in haustorium of P. viticola and nucleus of host cell which was associated with a nucleus collapse at 10 days post-inoculation. Taken together, these results suggested that VpPR10.2 might play an important role in host plant defense against P. viticola infection.     

FOXG1在结直肠癌侵袭及转移中的作用及机制

构建叉头框G1(Forkhead box G1,FOXG1)的慢病毒干扰(shRNA)质粒及表达质粒,通过敲低和过表达FOXG1探讨其对结直肠癌细胞上皮-间质转化EMT的作用及其机制。应用Western blotting检测FOXG1在RKO、SW480、SW620、LOVO、DLD-1五种结直肠癌细胞中蛋白的表达水平,设计并合成FOXG1的shRNA片段(shFOXG1),运用DNA重组技术获得重组质粒,经双酶切技术及测序方法鉴定后进行慢病毒的包装、纯化及稳定转染,经筛选后获得稳定的结直肠癌细胞株,通过Western blotting和qRT-PCR技术检测FOXG1敲低和过表达效率及EMT关键因子E-cadherin、Vimentin、Fibronectin、Snail、Twist mRNA和蛋白的变化,光学显微镜观察敲低后细胞形态学变化,通过划痕实验检测迁移能力变化,Transwell检测侵袭迁移能力的变化。5种结直肠癌细胞中,FOXG1在RKO细胞中蛋白表达量最高,而在DLD-1细胞中表达量最低,与对照组相比较,在RKO细胞中敲低FOXG1,细胞形态由长梭型变成了类圆形或者多边形,细胞极性和紧密连接增加,细胞迁移距离明显降低,侵袭转移穿过小室的细胞数也明显减少,EMT关键因子E-cadherin表达增高,Vimentin、Fibronectin、Snail、Twist表达降低,过表达FOXG1组则相反。FOXG1在结直肠癌中高表达,这种基因的高表达能够促进结直肠癌细胞的侵袭和转移,对结直肠癌细胞的EMT起着重要的调控作用。     

中国旅游业碳排放效率的空间格局及其影响因素

旅游业碳排放效率作为旅游业绿色全要素生产率指标,是衡量旅游业碳排放与旅游经济增长之间关系的重要工具。借助SBM模型测算了中国省际旅游业碳排放效率,并利用ESDA和GWR方法分析了旅游业碳排放效率的空间格局及其影响因素的时空异质性。结果表明:中国旅游业碳排放效率呈现缓慢提升态势,但总体水平仍较低。旅游业碳排放效率的空间集聚特征明显,形成了以上海为中心的高值集聚区和以西北省份为中心的低值集聚区。旅游业碳排放效率及其空间格局演化是多因素共同作用的结果,旅游经济规模对中西部地区旅游业碳排放效率的提升作用较强;城镇化的促进作用逐步减弱,且在多数省份开始产生抑制作用;技术效应的提升作用高值区从中东部转移至华北和东北地区;旅游业产权结构对南部地区的推动作用也逐步凸显;结构效应主要对西南地区起促进作用。这为优化和提升旅游业碳排放效率提供了理论依据。     

A Multifunctional Separator Enables Safe and Durable Lithium/Magnesium–Sulfur Batteries under Elevated Temperature

Rechargeable metal–sulfur batteries encounter severe safety hazards and fast capacity decay, caused by the flammable and shrinkable separator and unwanted polysulfide dissolution under elevated temperatures. Herein, a multifunctional Janus separator is designed by integrating temperature endurable electrospinning polyimide nonwovens with a copper nanowire‐graphene nanosheet functional layer and a rigid lithium lanthanum zirconium oxide‐polyethylene oxide matrix. Such architecture offers multifold advantages: i) intrinsically high dimensional stability and flame‐retardant capability, ii) excellent electrolyte wettability and effective metal dendritic growth inhibition, and iii) powerful physical blockage/chemical anchoring capability for the shuttled polysulfides. As a consequence, the as constructed lithium–sulfur battery using a pure sulfur cathode displays an outstandingly high discharge capacity of 1402.1 mAh g^?1 and a record high cycling stability (approximately average 0.24% capacity decay per cycle within 300 cycles) at 80 °C, outperforming the state‐of‐the‐art results in the literature. Promisingly, a high sulfur mass loading of ≈3.0 mg cm^?2 and a record low electrolyte/sulfur ratio of 6.0 are achieved. This functional separator also performs well for a high temperature magnesium–sulfur battery. This work demonstrates a new concept for high performance metal–sulfur battery design and promises safe and durable operation of the next generation energy storage systems.     

湿地自然保护区旅游者环境教育感知研究——以盐城丹顶鹤、麋鹿国家自然保护区为例

环境教育是当前生态旅游研究中的热点论题。基于生态旅游动机、环境教育途径、环境教育感知及环境教育效果4个结构变量,以生态旅游发展处于起步阶段的盐城丹顶鹤保护区和处于稳定发展阶段的盐城麋鹿保护区为例,构建湿地自然保护区旅游者环境教育感知影响结构关系模型,深入分析不同生命周期阶段生态旅游地旅游者环境教育感知分异及其影响因素。结果表明:(1)生态旅游动机、环境教育途径、环境教育感知均对环境教育效果产生正向影响。丹顶鹤保护区生态旅游动机对环境教育效果产生显著正向影响,环境教育途径、环境教育感知对环境教育效果均产生正向影响;麋鹿保护区生态旅游动机、环境教育途径均对环境教育效果产生正向影响,环境教育感知对环境教育效果产生显著正向影响。(2)在生态旅游动机、环境教育途径、环境教育感知3个分维度上,丹顶鹤保护区分别以一般生态旅游动机、常规环境教育途径、表层环境教育感知为主,麋鹿保护区则分别以严格生态旅游动机、专门环境教育途径、深度环境教育感知为主。(3)不同生命周期阶段生态旅游地游客环境教育效果存在差异。丹顶鹤保护区游客环境教育效果主要集中在态度、行为效果上,意识效果为辅,知识、技能效果作用较小;麋鹿保护区游客环境教育效果则以知识、态度效果为主,行为、技能、意识效果均起辅助作用。     

BF、DRB、DQB、TAPl和IFN-γ基因作为猪抗病育种分子标记的可行性初步分析

疾病的抗性具有一定的遗传差异背景,而免疫学和分子生物学等相关学科技术的发展及社会对猪肉产品质量和动物福利等问题的日益关注,赋予了开展猪抗病育种尤其是分子标记辅助选择研究的必要性.选择了补体B因子基因(BF)、2个MHC Ⅱ类基因(DRB和DQB)、1个抗原加工递呈相关基因(TAPI)和1个Ⅱ型干扰素基因(IFN-γ)等5个具有重要免疫功能的基因作为候选基因,对华农温氏Ⅰ号这一商品化配套系的基础群进行基因型分布检测,及基因型与0～100kg日增重或100kg背膘厚间的关联分析,以探讨开发相关分子标记的可行性.参与基因型检测的样本包括杜洛克、长白、皮特兰和大白4个品种.结果表明TAPI和IFN-γ的基因型在参与生产性能高度选择的各品种内处于Hardy-weinberg平衡(P>0.05),BF在除了大白品种外的其它3品种中均平衡(P>0.05),DRB和DQB为高度不平衡(P<0.0001).基因型与表型的关联分析显示大白品种中IFN-γ的基因型对0～100 kg日增重有影响(P<0.01),长白品种中DRB的基因型与100 kg背膘厚有关(P<0.05),其它品种或其它基因没有检测到与之相关的显著性差异(P>0.05).这5个基因在4个品种中至少TAPI基因表现出与相关生产性状无关,因此对它抗病性能的选择利用将不会造成其它性能的下降.     

Localization, expression change in PRRSV infection and association analysis of the porcine TAP1 gene

The transporter associated with antigen processing (TAP) translocates antigenic peptides from the cytosol into the lumen of the endoplasmic reticular and plays a critical role in the major histocompatibility complex (MHC) class I molecule-mediated antigenic presentation pathway. In this study, the porcine TAP1 gene was mapped to the pig chromosome 7 (SSC7) and was closely linked to the marker SSC2B02 (retention fraction=43%, LOD=15.18). Subcellular localization of TAP1 by transient transfection of PK15 cells indicated that the TAP1 protein might be located in the endoplasmic reticulum (ER) in pig kidney epithelial cells (PK-15). Gene expression analysis by semi-quantitative RT-PCR revealed that TAP1 was selectively expressed in some immune and immune-related tissues. Quantitative real-time PCR (qRT-PCR) analysis revealed that this gene was up-regulated after treatments that mimic viral and bacterial infection (polyriboinosinic-polyribocytidylic acid (poly(I:C)) and lipopolysaccharide (LPS), respectively). In addition, elevated TAP1 expression was detected after porcine reproductive and respiratory syndrome virus (PRRSV) infection in porcine white blood cells (WBCs). One single nucleotide polymorphism (SNP) in exon 3 of TAP1 was detected in a Landrace pig population by Bsp143I restriction enzyme digestion. Different genotypes of this SNP had significant associations (P<0.05) with the red blood cell distribution width (RDW) of 1-day-old (1 d) pigs (P=0.0168), the PRRSV antibody level (PRRSV Ab) (P=0.0445) and the absolute lymphocyte count (LYM#) (P=0.024) of 17 d pigs. Our results showed that the TAP1 gene might have important roles in swine immune responses, and these results provide useful information for further functional studies.