Identifying and Characterizing a Novel Peritrophic Matrix Protein (MdPM-17) Associated With Antibacterial Response From the Housefly,Musca domestica (Diptera: Muscidae)

Peritrophic matrix/membrane (PM) critically prevents the midgut of insects from external invasion by microbes. The proteins in the peritrophic membrane are its major structural components. Additionally, they determine the formation and function of this membrane. However, the role of PM proteins in immune regulation is unclear. Herein, we isolated a novel PM protein (MdPM-17) from Musca domestica larvae. Further, the function of MdPM-17 in regulating host innate immunity was identified. Results showed that the cDNA of MdPM-17 full is 635 bp in length. Moreover, it consists of a 477-bp open reading frame encoding 158 amino acid residues. These amino acid residues are composed of two Chitin-binding type-2 domain (ChtBD2) and 19 amino acids as a signal peptide. Moreover, tissue distribution analysis indicates that MdPM-17 was enriched expressed in midgut, and moderate levels in the fat body, foregut, and malpighian tubule. Notably, MdPM-17 recombinant protein showed high chitin-binding capacity, thus belongs to the Class III PM protein group. MdPM-17 protein silencing via RNA interference resulted in the expression of antimicrobial peptide (defensin, cecropins, and diptericin) genes, and this occurred after oral inoculation with exogenous microbes Escherichia coli (Enterobacteriales:Enterobacteriaceae), Staphylococcus aureus (Bacillales:Staphylococcaceae), and Candida albicans (Endomycetales:Saccharomycetaceae)). Therefore, all the antimicrobial peptide (AMP) gene expression levels are high in MdPM-17-depleted larvae during microbial infection compared to controls. Consequently, these findings indicate that MdPM-17 protein is associated with the antibacterial response from the housefly.     

大型贯流式泵站快速门加速启动过渡过程

为研究大型贯流式泵站机组闸门加速启动过程中的外特性参数变化及流态变化,对灯泡贯流泵机组进行三维建模,采用Fluent软件中的UDF来控制闸门的启动过程,使用铺层法动网格技术来控制闸门处网格生成与消灭,并设定S-A模型作为湍流模型,对灯泡贯流泵机组启动过程进行瞬态数值模拟.计算结果表明:当贯流泵机组快速门以10倍设计速度启动时,机组的转速与流量将以更快的速度达到额定转速与额定流量,同时瞬间最大倒灌流量相比未加速启动时增加了30%.当贯流泵机组处于倒流状态时,靠近轮毂处叶轮叶道压力面的压强呈现出从叶轮进水边向出水边逐渐递增的分布规律.当机组处于零流量的临界状态时,混乱的流态导致压力集中及脱流现象加重,叶轮进水边负压区范围扩大且程度加深.     

基于玻璃化转变的稻谷变温热风干燥工艺研究

为保证稻谷干燥后品质、提高干燥效率,基于不同含水率稻谷的玻璃化转变温度,提出变温热风干燥工艺。采用三因素五水平中心组合试验方法,以稻谷温度、初始含水率和热风风速为影响因素,以稻谷爆腰指数、整精米率和干燥时间为评价指标,研究稻谷玻璃化转变温度、恒温和变温干燥特性,模拟解析稻谷干燥过程中传热传质规律,以5、10、15℃的变温幅度进行变温干燥试验。结果表明,稻谷玻璃化转变温度与其含水率呈负相关,恒温干燥最佳工艺参数为稻谷温度47℃、初始含水率22.0%、热风风速0.50 m/s,干燥后稻谷爆腰指数70、整精米率57.67%、干燥时间195 min;与恒温干燥相比,以5℃和10℃为变温幅度的变温干燥工艺,干燥后稻谷爆腰指数分别降低了20和10,整精米率提高12.6、7.7个百分点,干燥时间缩短30 min和60 min。研究表明,基于玻璃化转变的稻谷变温热风干燥工艺明显改善了稻谷干燥后品质,提高了干燥效率。     

Comparison of cholesterol levels among lipoprotein fractions separated by anion-exchange high-performance liquid chromatography in periparturient Holstein–Friesian dairy cows

Changes in lipoprotein profiles occur in dairy cows during the periparturient period and in cows with transition cow disease. Here, the lipoprotein profiles of Holstein–Friesian dairy cows during the periparturient period were obtained by anion-exchange, high-performance liquid chromatography to evaluate the usefulness of lipoprotein profile evaluation during the periparturient period and in cows with fatty liver and milk fever. Lipoprotein levels (including total and high- (HDL-C) and low-density lipoprotein (LDL-C) cholesterol) in 10 healthy cows were low 4 weeks prepartum, with the lowest values at calving or within 1 week of calving; the values increased at 8 weeks postpartum. The lipoprotein levels were measured in 16 cows diagnosed with fatty liver (n=10) or milk fever (n=6) and compared to 10 healthy dairy cows. A significant difference was observed in HDL-C between healthy cows (at calving and 1 week postpartum), and the fatty liver and milk fever cows. Cows with fatty liver and milk fever had a lower mean HDL-C than the 10 healthy dairy cows at calving and 1 week postpartum. HDL-C might be a good indicator of energy balance for differentiating healthy cows from those with transition cow disease.     

植物生长调节剂、基质对三个品种费约果扦插生根的影响

选取五年生健壮费约果树为母株，采用L9(33)正交设计法研究植物生长调节剂、基质对三个品种费约果半木质化枝条扦插生根的影响。本试验结果表明：不同品种、植物生长调节剂和基质处理的生根的影响呈显著性水平。影响费约果扦插枝条生根率因素的主次顺序为品种>植物生长调节剂>基质；影响根长因素的主次顺序为基质>植物生长调节剂>品种；影响插穗根数的因素主次顺序品种>基质>植物生长调节剂。Gemini品种经1000 mg/L ABT浸泡两分钟，以腐叶土+珍珠岩为基质，生根效果最好，生根率为70.00%，平均根长为8.85 cm，平均根数为10.22条/穗；Unique品种经1000 mg/L ABT浸泡两分钟，以腐叶土+蛭石为基质，生根效果较好，生根率为56.67%，平均根长为9.32 cm，平均根数为12.33条/穗；Coolidge品种生根率低，均≤20 %。     

Pearl grafting: Tracking the biological origin of nuclei by straightforward immunological methods

French Polynesia is renowned for the production of Tahitian black pearl. These gems are obtained by grafting a nucleus into the gonad of a receiving oyster together with a graft, i.e. a small section of mantle tissue of a donor oyster. This procedure initiates the formation of a pearl sack around the nucleus, and subsequently, the deposition of concentric layers of nacre. The nucleus plays a key‐role in pearl formation and its characteristics influence markedly the quality of the final product. As it is manufactured from mollusc shells, it contains a small percentage of organics. In the present paper, we used a set of biochemical techniques to characterize and compare the organic matrices from two types of nuclei that are currently used in French Polynesia: that from the freshwater mussel Amblema sp., and that from the pearl oyster Pinctada sp. To this end, we extracted the matrices from nuclei and performed FT‐IR, monodimensional electrophoresis, and enzyme‐linked immuno‐sorbent assay (ELISA). Our data show that the matrix associated with Amblema nuclei has a very different biochemical signature from that of Pinctada nuclei, a fact that may explain the improved tolerance of grafted oysters to nuclei of Pinctada origin. In the absence of complex physical methods of investigation, simple immunological techniques and FT‐IR performed on the extracted organic matrix are extremely reliable and effective for discriminating nuclei from these two sources. We assert that such techniques can be used as a diagnostic test to track unambiguously the biological origin of nuclei to avoid fraud.     

农牧交错带农牧系统氮素流动与环境效应——以山西省为例

【目的】探明山西省农牧交错带农牧生产系统的氮素流动特征及其环境效应,进一步为山西实施区域养分资源管理、加快农牧交错带产业结构调整提供科学依据。【方法】在整理统计资料、文献数据和实地调研的基础上,使用食物链养分流动模型(nutrient flows in food chains,environment and resources use,NUFER)和GIS,估算山西省农牧交错带(主要涉及大同、朔州、忻州、吕梁、临汾和太原等6个地市)42个县区农牧生产系统的氮素账户平衡、流动路径及损失途径。【结果】不同县区农田化学氮肥投入存在"两极分化"的现象,投入水平范围在6.7—253 kg·hm~(-2),极值间相差38倍;各县区农田氮素的投入结构也表现出较大差异,主要跟当地化学氮肥施用习惯及农业种植结构有很大的关系;单位农田面积农作物主产品的氮素携出量范围在19.11—96.75kg·hm~(-2),空间上整体呈现南北高、中部低的变化趋势;不同县区农田氮素盈余量在-16—202 kg·hm~(-2),氮素亏缺与盈余情况并存;区内畜牧生产系统中外源饲料氮素投入差异较大,朔州市的山阴县外源饲料氮素投入高达0.94×104 t,而忻州的五寨、临汾的隰县、大宁和蒲县,则可以通过作物生产系统来满足畜牧生产系统的饲料需求,也充分反映了各县区畜牧业养殖规模和农牧产业结构存在较大差异;区内单位面积农田动物主产品氮素携出量范围在1.51—27.50 kg·hm~(-2),极差25.99 kg·hm~(-2),说明各县区畜牧生产系统的生产力水平差异较大,单位农田面积动物主产品的氮素携出量13 kg·hm~(-2)的分布在区域北部朔州市的山阴、怀仁、大同等县区,表明这些县区畜牧生产系统中的氮素利用率较高;单位耕地面积畜禽粪尿氮素负荷较高(50 kg·hm~(-2))的县区主要分布在区域北部;农牧生产系统氮素损失的空间分布格局明显:一级区(200 kg·hm~(-2))分布在区域北部,二级区(120—200 kg·hm~(-2))分布在区域南部和北部,三级区(120 kg·hm~(-2))主要分布在区域中部,今后应重点关注区域北部农牧业生产过程中的氮素损失及环境问题。【结论】农业生产结构不合理、"农牧分离"是造成农牧生产系统氮素利用率低下的主要原因,今后农田养分资源综合管理要在空间上合理配置氮素资源,在养分投入上既要考虑化学氮肥和粪尿氮素的投入,还要兼顾来源于环境投入部分的氮素,更要注重和畜牧生产系统的耦合,以最小的环境代价生产更多的农牧产品。     

Conservation needs for the endangered New Zealand sea lion,Phocarctos hookeri

1. Understanding population size and trend is critical information in species management and conservation. To enable accurate population trend estimates, consistent robust monitoring of a species is essential, particularly for a species such as the New Zealand (NZ) sea lion, Phocarctos hookeri , which has experienced an almost continuous decline in pup production since the late 1990s.
2. This research examines the pup production estimates for all known breeding sites for this species, and using a stage‐structured matrix population model, estimates population size and trend between 1995 and 2015.
3. Overall, it is estimated that 2,316 pups were born in 2015, a decrease of 13% since 1995 and a 27% decline since the highest pup production estimate in 1998. This decline has been driven by the significant decline of 48% at the main breeding area, the Auckland Islands since 1998.
4. Using the stage‐structured matrix population model a total species population size of 11,767 sea lions (95% CrI: 10,790–12,923) was estimated. This is the lowest population size of any sea lion species. Trend data for the Auckland Islands indicated that pup and population numbers have decreased at 1.9% yr^?1 in the last 20 yr, while total species population decline is 0.6% yr^?1.
5. Estimates of population trends for this species have been hindered by inconsistent monitoring at most breeding sites. This study strengthens the growing field of research highlighting the need for consistent long‐term monitoring for the conservation management of endangered species.

     

行星变速机构换挡变胞与其构态属性自动识别

针对数学表征行星变速机构换挡变胞过程及自动识别各挡位构态属性较难的问题，首先，解析了行星变速机构变胞理论，基于机构转换法定义相对转速意义下行星排构件间运动副约束函数的转换规则，构建以约束函数为元素的行星变速机构构件和关联关系的邻接矩阵；然后，根据换挡逻辑分析了操纵离合器和制动器的换挡变胞过程，基于邻接矩阵分别推导这两种换挡构态演变的变胞方程，建立包含行星排空转和整体回转等特殊构态的判别准则，结合实例分析揭示换挡变胞机理；最后，通过建立相对转速方程和行星变速机构特性参数识别，结合行星变速机构等效拓扑模型的约束条件，提出了基于构态变胞方程的行星变速机构传动比和转矩自动建模和求解方法，实现了行星变速机构各挡位构态属性的自动识别。以某拖拉机行星变速器为例进行了分析，验证了该方法的可行性和有效性。     

液压机械全功率换段方法及功率过渡特性

为了解决液压机械无级传动换段过程中存在的动力中断和换段冲击等问题,基于当前段与目标段双制动器结合重叠,提出全新的液压机械全功率换段方法,并深入探究全功率换段过程功率过渡机理及控制方法。该文以两段等差式液压机械为研究对象,在双制动器结合重叠的动力换段方式的基础上,提出了五阶段液压机械全功率换段方法,通过理论分析与试验相结合的方法,研究了换段过程中液压机械转矩特性和功率特性随液压回路压差的变化规律,液压回路压差随变排量液压元件排量的变化规律。结果表明,在双制动器结合重叠的动力换段中,通过调节变排量液压元件的排量比,能够控制液压回路的高低压侧压差改变、互换,进而控制当前段制动器转矩向目标制动器有序转移,在双制动器结合重叠中完成换段,实现换段过程传递全功率。输入转速保持1 000 r/min不变,进出换段时定排量液压元件转速无波动,输出扭矩波动量约为5 N·m(负载扭矩为60 N·m和150 N·m)。该研究揭示了液压机械全功率换段的功率过渡机理,可为全功率换段的后续研究及液压机械应用提供了参考。