冻干水痘减毒活疫苗转瓶生产工艺的建立

应用旋转培养的方法,建立冻干水痘减毒活疫苗的生产工艺。选择长成致密单层的2BS细胞,接种带状疱疹病毒Oka株,待细胞病变达75％以上时,收获病毒液,经超声破碎、离心、澄清,冻干后,按常规检定,疫苗各项检定符合《WHO水痘活疫苗规程》及《冻干水痘减毒活疫苗制造及检定试行规程》要求。与克氏瓶相比,应用旋转培养,不但提高了疫苗单产,降低了牛血清蛋白残留量,而且疫苗质量也保持稳定。     

石羊河中游沙漠化逆转过程土壤种子库的动态变化

在石羊河中游,应用空间代替时间的方法,选择流动沙丘以及封育恢复5a、15a和25a的沙漠化逆转过程序列,研究了沙漠化逆转过程土壤种子库的变化特征。结果表明:石羊河中游沙漠化土地土壤种子库由4科12种植物组成,种子库主要分布于表层0-5cm。在沙漠化逆转过程中,土壤种子库物种数趋于增加,物种组成以1年生草本植物占优势逐渐向多年生草本植物和半灌木植物转变;种子库密度、表层土壤种子比例、物种多样性指数、与地上植被的相似性呈现先增大后降低趋势;沙漠化土地生态恢复间隔的时间越长,土壤种子库间的相似性程度越低;沙漠化土地与地带性植被区种子库的相似性逐渐增大,但是恢复25a沙漠化土地也仅达到0.36。研究认为,沙漠化逆转过程也是沙漠化土地土壤种子库向地带性植被土壤种子库演变的过程,而且是一个十分缓慢的过程,该研究有助于丰富干旱区土壤种子库的理论和指导干旱内陆河流域沙漠化土地的生态恢复实践。     

Trends in health research ethics in the Philippines during the American Colonial Period (1898‐1946)

Research involving human participants has been conducted in the Philippines since the beginning of the Spanish colonial period. Such studies are expected to adhere to internationally accepted ethical guidelines. This paper discusses trends in clinical research ethics in the Philippines during the American colonial period (1898‐1946). Specifically, studies were assessed on: 1) their observance of ethical protocols, including review; 2) identification of inclusion and exclusion criteria in the selection of participants; 3) use of vulnerable subjects; and 4) practice of the informed consent process. Only the informed consent process had a significant logistic correlation with progression of years. Recruitment of vulnerable groups was common during this period; children and prisoners were the most common participants. Trends in medical ethics in the Philippines reflected those in the United States prior to the publication of the Nuremberg Code, which served as a milestone in the protection of human welfare in clinical research.     

Forecasting species range dynamics with process‐explicit models: matching methods to applications

Knowing where species occur is fundamental to many ecological and environmental applications. Species distribution models (SDMs) are typically based on correlations between species occurrence data and environmental predictors, with ecological processes captured only implicitly. However, there is a growing interest in approaches that explicitly model processes such as physiology, dispersal, demography and biotic interactions. These models are believed to offer more robust predictions, particularly when extrapolating to novel conditions. Many process–explicit approaches are now available, but it is not clear how we can best draw on this expanded modelling toolbox to address ecological problems and inform management decisions. Here, we review a range of process–explicit models to determine their strengths and limitations, as well as their current use. Focusing on four common applications of SDMs – regulatory planning, extinction risk, climate refugia and invasive species – we then explore which models best meet management needs. We identify barriers to more widespread and effective use of process‐explicit models and outline how these might be overcome. As well as technical and data challenges, there is a pressing need for more thorough evaluation of model predictions to guide investment in method development and ensure the promise of these new approaches is fully realised.     

Characterization of the distribution of glucose oxidase in Penicillium sp. CBS 120262 and Aspergillus niger NRRL-3 cultures and its effect on integrated product recovery

Glucose oxidase (GO) is an important industrial enzyme typically purified from Penicillium and Aspergillus sp. As GO distribution within the cultures influences process design for maximal product recovery, distribution of GO activity in Penicillium sp. CBS 120262 and Aspergillus niger NRRL-3, during mid-exponential and stationary phases, is compared. On progression from mid-exponential to stationary phase, the percentage GO activity in the cytoplasm decreased 1.6- and 1.3-fold in Penicillium sp. and A. niger respectively. In Penicillium sp., a concomitant 1.8- and 1.9-fold decrease in the percentage GO activity in the cell envelope and slime mucilage respectively, translated into a 2.0-fold increase in the extracellular fluid. In A. niger, decreasing cytoplasmic GO activity was accompanied by 1.3-fold increases in the cell envelope and slime mucilage, with a 1.3-fold decrease in the extracellular fluid. Similar trends were observed in specific GO activities. As final GO activity recovered is governed by the purification program, recovery from the extracellular fluid plus cell extract or from the extracellular fluid only were compared through simulating processes of varying complexity. A critical yield for each purification stage was identified above which recovery from the extracellular fluid plus cell extract exceeded that from extracellular fluid alone. These results highlight the influence of microorganism, harvest time and efficiency of downstream process on GO activity delivered. In the systems studied, Penicillium sp. is the organism of choice and should be harvested during stationary phase. The purification process chosen should be informed by both enzyme distribution and individual purification stages yields.     

黑脊倒刺鲃生精细胞拟染色体的形成过程

电子显微镜观察了黑脊倒刺把生精细胞中拟染色体的形成过程。拟染色体在初级精原细胞中形成。在初级精原细胞的细胞核中,拟染色体前体物质先附着于核膜内侧,该处核膜崩溃并在拟染色体前体物质的内侧,新核膜形成。新核膜将拟染色体前体物质分隔出细胞核之外新核膜呈凹陷状。拟染色体前体物质集中于该凹陷中,并聚集成拟染色体。新核膜上有较大的空隙核内还有少量拟染色体前体物质通过该空隙进入核表面的凹陷中,并结合到拟染色体上黑脊倒刺鲃生精细胞拟染色体的形成方式与通常认为的核内物质通过核孔排出核外的方式不同,似可表明核内物质向外运输存在着另一种机制。拟染色体形成后不久就与线粒体结合,并离开核凹在以后的发育过程中,拟染色体又与线粒体分离。     

Primary processes in heme-based sensor proteins

A wide and still rapidly increasing range of heme-based sensor proteins has been discovered over the last two decades. At the molecular level, these proteins function as bistable switches in which the catalytic activity of an enzymatic domain is altered mostly by binding or dissociation of small gaseous ligands (O₂, NO or CO) to the heme in a sensor domain. The initial “signal” at the heme level is subsequently transmitted within the protein to the catalytic site, ultimately leading to adapted expression levels of specific proteins. Making use of the photolability of the heme-ligand bond that mimics thermal dissociation, early processes in this intra-protein signaling pathway can be followed using ultrafast optical spectroscopic techniques; they also occur on timescales accessible to molecular dynamics simulations. Experimental studies performed over the last decade on proteins including the sensors FixL (O₂), CooA (CO) and soluble guanylate cyclase (NO) are reviewed with an emphasis on emerging general mechanisms. After heme-ligand bond breaking, the ligand can escape from the heme pocket and eventually from the protein, or rebind directly to the heme. Remarkably, in all sensor proteins the rebinding, specifically of the sensed ligand, is highly efficient. This ”ligand trap” property possibly provides means to smoothen the effects of fast environmental fluctuations on the switching frequency. For 6-coordinate proteins, where exchange between an internal heme-bound residue and external gaseous ligands occurs, the study of early processes starting from the unliganded form indicates that mobility of the internal ligand may facilitate signal transfer. This article is part of a Special Issue entitled: Oxygen Binding and Sensing Proteins.     

大尺度生态水文模型的构建及其与GIS集成

基于过程模拟手段揭示森林植被的生态水文功能和变化机制,已经成为生态水文学研究的重要手段。由于陆地生态水文过程的非线性和尺度问题的广泛性,基于过程的坡面或小流域尺度的分布式水文模型不适合大流域的水文过程的分析和预测;另外,传统的水文模型主要侧重水文物理过程,只有充分耦合植被生态过程,才能从机制上揭示森林植被参与水文循环的调控作用。依据大流域的水文过程特点,从5个方面阐述了大尺度生态水文模型构建过程中的主要问题：①大尺度生态水文模型的概念和结构;②尺度的界定与匹配;③离散化数据集的建立,着重分析了植被覆盖、土壤质地、山地气候等主要数据集的建立方法;④分布式与集总式模型,这两类模型可以从他们的基本空间单元上进行区分,数字流域的建立和空间分析手段使得集总式模型和分布式模型得到了很好的结合;⑤生态水文模型与GIS的集成。分析了4种不同的集成方式,“松散型”的集成方式因其编程工作量小而被广泛采用。集成的目的不仅是要提高模拟的技术水平,更要提高系统整体的概念化水平。     

时间序列谱分析在作物究研中的应用探讨(一)

本文分两个部分分别探讨了单一和两维时间序列谱分析在研究作物量变过程规律中的意义、应用的原理和方法,并通过实例结果的分折表明这些方法的可行性,所揭示的生物学意义和这些方法的应用在研究作物量变过程中将可能具有的广泛的研究前景。     

Sperm competition mechanisms,confidence of paternity,and the evolution of paternal care in the golden egg bug (Phyllomorpha laciniata)

Theoretical models predict how paternal effort should vary depending on confidence of paternity and on the trade-offs between present and future reproduction. In this study we examine patterns of sperm precedence in Phyllomorpha laciniata and how confidence of paternity influences the willingness of males to carry eggs. Female golden egg bugs show a flexible pattern of oviposition behavior, which results in some eggs being carried by adults (mainly males) and some being laid on plants, where mortality rates are very high. Adults are more vulnerable to predators when carrying eggs; thus, it has been suggested that males should only accept eggs if there are chances that at least some of the eggs will be their true genetic offspring. We determined the confidence of paternity for naturally occurring individuals and its variation with the time. Paternity of eggs fertilized by the last males to mate with females previously mated in the field has been determined using amplified fragment length polymorphisms (AFLPs). The exclusion probability was 98%, showing that AFLP markers are suitable for paternity assignment. Sperm mixing seems the most likely mechanism of sperm competition, because the last male to copulate with field females sires an average of 43% of the eggs laid during the next five days. More importantly, the proportion of eggs sired does not change significantly during that period. We argue that intermediate levels of paternity can select for paternal care in this system because: (1) benefits of care in terms of offspring survival are very high; (2) males have nothing to gain from decreasing their parental effort in a given reproductive event because sperm mixing makes it difficult for males to reach high paternity levels and males are left with no cues to assess paternity; (3) males cannot chose to care for their offspring exclusively because they can neither discriminate their own eggs, nor can they predict when their own eggs will be produced; and (4) males suffer no loss of further matings with other females when they carry eggs. Thus, our findings do not support the traditional view that paternal investment is expected to arise only in species where confidence of paternity is high. The results suggest that females maximize the chances that several males will accept eggs at different times by promoting a mechanism of sperm mixing that ensures that all males that have copulated with a female have some chance of fathering offspring, that this probability remains constant with time, and that males have no cues as to when their own offspring will be produced.