人工降雨对湿地植物叶表面颗粒物滞留的影响

现阶段植物滞尘作为治理大气颗粒物污染的有效方法已被广泛接受与应用。已有研究表明,降雨等方式对植物叶表面颗粒物的滞留有着显著的影响,可有效地将颗粒物从叶表面去除,使植物再次具有滞留颗粒物的能力。由于自然降雨难以量化,现有研究大多采用模拟降雨的方式,将降雨特性量化为降雨强度、降雨历时等可控变量,但较少将降雨高度这一变量纳入研究。且大多以森林生态系统或者城市生态系统中常见的乔、灌、草等植物为主要研究对象,而忽略了处于水陆过渡带的湿地生态系统中植物的特殊性。湿地生态系统不仅可通过植物叶片等结构滞留颗粒物,还可依靠增强空气相对湿度促进颗粒物的吸收和积累,导致湿地植物滞尘规律的特殊性。因此,选择北京地区湿地生态系统内的4种常见植物（香蒲、菖蒲、芦苇和黄花鸢尾）作为研究对象,通过人工模拟降雨的方式,将降雨特性量化为降雨高度与降雨强度两个变量,共设置1 m （11 m）、2 m （10 m）两个不同降雨高度,30 mm/h、45 mm/h、60 mm/h三种不同降雨强度,并将颗粒物划分粗颗粒物（10—100 μm）、细颗粒物（3—10 μm）、超细颗粒物（0.4—3 μm）三种粒径范围。通过滤膜法获得单位叶面积颗粒物去除量,探讨人工降雨对湿地植物叶表面颗粒物滞留的影响。主要研究结果如下：（1）颗粒物去除量在粗颗粒物（10—100 μm）粒径范围内最高;（2）所试4种湿地植物中,菖蒲的颗粒物去除量位居前列;（3）只有在一定的范围内,植物叶表面颗粒物去除量才随降雨强度的增加而增加;（4）不同降雨高度下所试湿地植物叶表面颗粒物去除量无明显规律,降雨高度之间无显著差异（P>0.05）。     

细胞培养肉的生物伦理学思考

近年来,为了解决人类社会发展和环境资源的矛盾日益突出的问题,人造肉越来越多的进入人们的视野。通常所说的人造肉,可以分为植物蛋白肉和细胞培养肉。其中植物蛋白肉已经逐步开始商业化,细胞培养肉采用动物细胞进行培养,与真实肉制品更为接近。文中在分析细胞培养肉本质基础上,探讨细胞培养肉对肉类生产行业、消费者群体以及人类未来可持续发展的积极意义。在生物伦理学的视角下,研发和生产细胞培养肉有助于保障人类社会的可持续发展、提升动物福利、减少资源需求、改善肉制品营养功能,并为其他行业的发展提供新的增长点。此外,对于细胞培养肉生产涉及的食品安全、技术滥用、技术监管层面上的伦理风险提出进行了深入思考,希望能从生物伦理学的层面为人造肉行业的可持续发展提供参考。     

Growth-enhanced salmon modify stream ecosystem functioning

Use of fast-growing domesticated and/or genetically modified strains of fish is becoming increasingly common in aquaculture, increasing the likelihood of deliberate or accidental introductions into the wild. To date, their ecological impacts on ecosystems remain to be quantified. Here, using a controlled phenotype manipulation by implanting growth hormone in juvenile Atlantic salmon (Salmo salar), we found that growth-enhanced fish display changes in several phenotypic traits known to be important for ecosystem functioning, such as habitat use, morphology and excretion rate. Furthermore, these phenotypic changes were associated with significant impacts on the invertebrate community and key stream ecosystem functions such as primary production and leaf-litter decomposition. These findings provide novel evidence that introductions of growth-enhanced fish into the wild can affect the functioning of natural ecosystems and represent a form of intraspecific invasion. Consequently, environmental impact assessments of growth-enhanced organisms need to explicitly consider ecosystem-level effects.     

乌苏里江洪泛湿地蜻蜓目幼虫对水文连通阻断的生态响应

大型底栖动物的群落组成完整性能够指示和预测水生态环境的健康程度和变化趋势,已经在大量研究中得到验证。然而,群落水平的全部样品采集过程的复杂性并不利于它们的便捷应用。蜻蜓目幼虫是大型底栖动物中相对易于捕捉和识别的类群,并且拥有特别的两栖生命周期,它们的多样性特征以及对水体性质变化的敏感反应,使其成为湿地生态系统中非常广泛且适宜的指示生物。本研究通过比较乌苏里江人工堤坝内外两侧不同河段的河滨湿地中蜻蜓目幼虫的群落组成,分析堤坝阻隔对河滨湿地的生态影响,评估蜻蜓目幼虫对河滨湿地的环境指示特征。结果表明,随着乌苏里江由上游至下游,河滨湿地蜻蜓目幼虫的多样性愈加丰富;阻隔水文连通对蜻蜓目幼虫的生存繁育产生负面的作用,且越趋近下游,蜻蜓目幼虫受到人工堤坝的影响程度越显著;堤坝两侧不同物种的密度变化差异较小,主要区别在于直接与河流水文连通的样点多样性指数值的波动范围相对较大。     

利用细菌人工染色体技术构建整合F基因的重组MDV疫苗株*

目的:预防马立克氏病病毒(MDV)和新城疫病毒(NDV)混合感染鸡引起的疾病,构建表达NDV F蛋白的MDV疫苗株CVI988 BAC重组载体,并包装成重组病毒,为疫苗免疫提供更多的重组疫苗选择。方法:首先利用PCR扩增带有卡那霉素(Kanamycin,Kana)抗性基因片段的F基因,采用同源重组的方法将其整合到CVI988 BAC上,进一步诱导I-SceI表达敲除Kana基因而获得重组质粒CVI988 BAC-F。通过磷酸钙法转染鸡胚成纤维细胞获得重组病毒。结果:Western blot和间接免疫荧光实验证实重组病毒能够表达F蛋白。病毒生长曲线和蚀斑大小测定结果表明,F基因的插入不影响病毒的体外增殖。结论:利用BAC技术成功构建了整合F基因的重组MDV病毒CVI988 BAC-F,为MDV重组疫苗研发,防控NDV与MDV共感染奠定了基础。     

Fixed-time artificial insemination protocols on brazilian locally adapted breed gilts on ovulatory response and embryo production

The aim of this study was to use estrus synchronization protocols to favor fixed-time artificial insemination and consequently fixed-time embryo collection, and increase embryo production using eCG, in gits. In a cross over design, nine Piau breed gilts were subjected to 18 days of oral progesterone; P4 group did not receive any further; GnRH group received 25µg of GnRH 104 hours after the final application of P4; and eCG+GnRH group received 1000IU of eCG 24 hours after the final P4 in addition to GnRH for subsequent embryo collection, that was performed six days after first AI, by laparotomy. Artificial insemination was performed after 12 and 24 hours of estrus in P4 group, and 128 and 144 hours in GnRH and eCG+GnRH groups. The number of CL (8.6±3.9; 8.3±2.1; 26.7±15.0) and anovulatory follicles (4.3±3.7; 3.9±3.9; 17.2±9.5) was higher in the eCG+GnRH gilts (P<0.05). However, the use of 1000 IU of eCG reduced (P<0.05) the number of total structures (5.2±3.6; 5.1±3.1; 1.7±2.7), viable embryos (5.0±3.5; 4.8±3.3; 0.4±0.7), freezable embryos (3.6±3.4; 3.3±3.8; 0.1±0.3) and recovery rate (63.7±38.9; 58.6±24.7; 5.38±9.5). P4 and GnRH protocols were effective in the production and recovery of embryos. However, the use of 1000 IU of eCG, 24 hours after P4, was not effective in promoting the production of embryos, although the animals had superovulated.     

云南特有螺类光肋螺蛳主要生物学特征研究

光肋螺蛳（Margarya mansugi）是仅分布于云南省的特有螺类。受过度捕捞、栖息环境破坏等人为因素影响,光肋螺蛳自然种群急剧萎缩,目前已被世界自然保护联盟列为极危物种。由于光肋螺蛳的研究资料匮乏,其生物学特征尚未被完全掌握,制约了光肋螺蛳保护对策的制定。为此,通过室内人工驯养观察,记述了光肋螺蛳的形态、活动习性、食性、生长和繁殖等主要生物学特征。光肋螺蛳壳质厚且坚硬,呈长圆锥形,褐色,角质厣,螺壳一般有5~6个螺层,体螺层有4条环肋,雌螺体型一般比同龄雄螺大;喜栖息在水体底层,夜晚活动频率明显高于白天;主要以藻类为食,成螺经驯化可摄食人工配合饲料;仔螺、幼螺和成螺的生长速度顺次降低;性成熟时间需要两年以上,卵胎生,终年生产,一般在白天交配,交配时间7~10 h,分批产仔,每次产仔1~2只,观察到的一只雌螺分9批产仔,共产仔螺14只。从受精到仔螺产出需85 d以上。本研究可为光肋螺蛳基础生物学研究积累资料,同时也可为高原湖泊特有螺类的人工驯养繁育提供参考。     

A gait index may underestimate changes of gait: a comparison of the Movement Deviation Profile and the Gait Deviation Index

The ability of the Movement Deviation Profile (MDP) and Gait Deviation Index (GDI) to detect gait changes was compared in a child with cerebral palsy who underwent game training. Conventional gait analysis showed that sagittal plane angles became mirrored about normality after training. Despite considerable gait changes, the GDI showed minimal change, while the MDP detected a difference equal to a shift between 10-9 on the Functional Assessment Questionnaire scale. Responses of the GDI and MDP were examined during a synthetic transition of the patient's curves from before intervention to a state mirrored about normality. The GDI showed a symmetric response on the two opposite sides of normality but the neural network based MDP gave an asymmetric response reflecting faithfully the unequal biomechanical consequences of joint angle changes. In conclusion, the MDP can detect altered gait even if the changes are missed by the GDI.     

Finite element analysis of Stryker Xia pedicle screw in artificial bone samples with and without supplemental cement augmentation

A validated, using in vitro biomechanical testing, finite element model was used to evaluate the affects of (1) cement augmentation and (2) an intact posterior cortex in osteoporotic bone. The presence of augmentation and/or a posterior cortical cortex increased the stabilization of the pedicle screw 2–5 fold. Placement of cement influenced failure load and toggle; with distal placement having the largest increase in failure load and decrease in cephalad–caudad toggle. The presence of posterior cortex caused a decrease in the amount of toggle, a proximal shift of the center of rotation and an increase in the maximum failure force.