A CAL program to teach the basic principles of genetic engineering—a change from the traditional approach

An interactive computer-assisted learning program written for the BBC microcomputer to teach the basic principles of genetic engineering is described. The pro-gram makes extensive use of colour, graphics, and animation and is aimed at A-level students of biology. Students select, from a menu, to investigate one of a number of identified processes involved in the overall production of a protein, each of which is treated as a self-contained unit. An assessment of how much of the factual information the student has learned is provided in the form of a computer 'adventure game' which is not only challenging but fun to play. Briefly, the student is led into an imaginary laboratory and must choose from shelves those essential items (e.g. reagents, starting materials, techniques) to progress through several stages culminating in the production of genetically engineered bacteria capable of producing a specific protein.     

Crypsis in a heterogeneous environment: relationships between changeable polymorphic colour patterns and behaviour in a galaxiid fish

1. The ability to achieve optimal camouflage varies between microhabitats in heterogeneous environments, potentially restricting individuals to a single habitat or imposing a compromise on crypsis to match several habitats. However, animals may exhibit morphological and behavioural attributes that enhance crypsis in different habitats. 2. We used an undescribed fish species, Galaxias‘nebula’, to investigate two objectives. First, we examined two potential methods of enhancing crypsis: change in colour pattern and selection of a suitable background. Second, we characterised the colour pattern of this unstudied fish and assessed its capacity for crypsis. 3. No background selection was apparent but the area of dark pigment expressed varied between backgrounds, which may negate the requirement to be choosy about habitats. The capacity to change colour and selection of a background that maximises crypsis are most likely separate, non‐mutually exclusive strategies. 4. Galaxias‘nebula’ exhibits polymorphic, non‐interchangeable colour patterns that have elements of both background pattern matching and disruptive colouration. This, coupled with habitat characteristics, suggests a combination of generalist and specialist strategies of habitat use. The fish’s camouflage strategy and air‐breathing ability may be key to survival under increasing pressure from habitat degradation and invasive predators.     

冻干加热处理凝血因子类制剂的病毒灭活验证

在病毒灭活验证过程中,比较了冻干后不同加热方法对凝血因子类制剂中伪狂犬病毒(PRV)的灭活效果,包括80℃干烤72h、100℃水浴加热30min以及100℃蒸汽加热30min方法。结果表明80℃干烤72h对制品中PRV灭活较彻底,另外两种方法对制品中PRV的灭活效果均不理想。     

SHIV病毒在猴体内的复制与传代

目的为建立SHIV艾滋病动物模型提供毒力较强的病毒株,将新合成的SHIV XJ02170病毒适应猴体,并增强其毒力。方法实验前采集猴血清并进行血清学检查和PCR检测。选出13只无SIV,STLV1,SRV D和B病毒感染的猴。第一批实验,将SHIV前病毒DNA质粒经肌肉注射到猴体内,每只500μg;SHIV病毒液,经静脉注射到猴体内,每只2ml。病毒质粒和病毒液各接种2只猴。当第一批猴体检出病毒后,10ml感染猴的全血,抗凝后静脉注射到第二批猴体内,当第二批猴检出病毒后再将10ml感染猴的全血静脉注射到第三批猴体内,连续传代4次。每批实验均定期采集血液标本,分别用肝素和EDTA抗凝,进行病毒分离;病毒基因PCR检测;CD4,CD8测定;病毒抗体检测。结果SHIV XJ02170病毒和SHIV XJ02170前病毒DNA质粒在猴体内的传代中均能分离出病毒;从传代猴的血浆和外周血单核细胞(PBMC)中检出了病毒DNA和RNA基因;CD4,CD8测定结果显示有暂时性倒置现象,后变为正常倒置与正常交替出现;在传代的猴血清中检测出特异性HIV病毒抗体。结论SHIV XJ02170病毒与SHIV XJ02170前病毒DNA质粒,均能在恒河猴体内复制。     

Current Status for High Titre Poxvirus Stock Preparation in CEF Under Serum-Free Medium Conditions: Implication for Vaccine Development

In light of the recent detection of BSE in North America and its endemic nature in other regions of the world, there is a real need to employ cell culture conditions that do not require any animal-derived material. Here we report the use of an ultra-low protein serum-free medium (VP-SFM, Invitrogen) for the amplification of poxviruses in primary chicken embryo fibroblasts (CEF). We compared the amplification of four different poxviruses (canarypox, modified Ankara Virus (MVA), vaccinia virus strain Copenhagen and myxoma strain Lausanne) in three different media: DMEM 10%, DMEM 2% and serum-free medium VP-SFM. VP-SFM is a serum-free, ultra-low protein medium containing no proteins or peptides of human or animal origin designed to support the replication of viruses and the production of recombinant proteins and monoclonal antibodies. Our results show that high titre poxvirus stocks can be prepared in VP-SFM equivalent to that prepared in serum containing medium.     

Numerical Approaches to Life Cycle Interpretation - The case of the Ecoinvent’96 database (10 pp)

Goal, Scope and Background To strengthen the evaluative power of LCA, life cycle interpretation should be further developed. A previous contribution (Heijungs & Kleijn 2001) elaborated five examples of concrete methods within the subset of numerical approaches towards interpretation. These methods were: contribution analysis, perturbation analysis, uncertainty analysis, comparative analysis, and discernibility analysis. Developments in software have enabled the possibility to apply the five example methods to explore the much-used Ecoinvent”96 database.Discussion of Methods The numerical approaches implemented in this study include contribution analysis, perturbation analysis, uncertainty analysis, comparative analysis, discernibility analysis and the newly developed key issue analysis. The data used comes from a very large process database: Ecoinvent’96, containing 1163 processes, 1181 economic flows and 571 environmental flows. Conclusions Results are twofold: they serve as a benchmark to the usefulness and feasibility of these numerical approaches, and they shed light on the question of stability and structure in an often-used large system of interconnected processes. Most of the approaches perform quite well: computation time on a moderate PC is between a few seconds a few minutes. Only Monte Carlo analyses may require much longer, but even then it appears that most questions can be answered within a few hours. Moreover, analytical expressions for error propagation are much faster than Monte Carlo analyses, while giving almost identical results. Despite the fact that many processes are connected to each other, leading to the possibility of a very unstable system and very sensitive coefficients, the overall results show that most results are not extremely uncertain. There are, however, some exceptions to this positive message.     

人类巨细胞病毒、EB病毒和单纯疱疹病毒1型与慢性牙周炎的相关性研究

目的　研究人类巨细胞病毒( HCMV)、Epstein- Barr病毒( EBV)和单纯疱疹病毒1型( HSV- 1)与慢性牙周炎的相关性。方法　收集6 2例慢性牙周炎患者(男性2 7例,女性35例;平均年龄5 3岁)的牙周炎部位,轻度龈炎部位的龈下菌斑,提取DNA后使用巢式PCR检测HCMV、EBV和HSV- 1,比较分析它们在同一患者不同部位的检出率。结果　牙周炎部位的HCMV检出率为38.7% ,EBV的检出率为5 8.0 % ,HSV- 1的检出率为30 .6 % ,2种以上病毒合并感染的检出率为4 0 .3% ;轻度龈炎部位的HCMV检出率为12 .9% ,EBV为19.4 % ,HSV- 1为9.7% ,2种以上病毒合并感染的检出率为8.0 %。这3种病毒及其合并感染在牙周炎部位的检出率均高于轻度龈炎部位,差异有统计学意义( P<0 .0 5 )。结论　提示HCMV、EBV、HSV- 1与慢性牙周炎有相关性。     

消杀型纳米催化剂抗病毒作用的研究

本文探讨112种消杀型纳米催化剂吸附与灭活病毒的功效,为开发新型抗病毒纳米材料提供理论依据。我们将各种纳米催化剂与副流感病毒、人疱疹病毒Ⅰ型、腺病毒1型及5型作用一定时间后,分别以血凝试验及观察CPE变化的方法判断纳米材料对各种病毒的吸附与灭活作用,并在电子显微镜下观察纳米材料对病毒的吸附情况。结果在所检测的112种纳米催化剂中,用血凝试验分别筛选出强吸附力催化剂 29 种、中吸附力催化剂 36 种、弱吸附力催化剂47种。其中,13 种强吸附力催化剂对副流感病毒的吸附率在 87.5%~93.75%之间,并以 AB 24的抗病毒效果最好。