Bacterial olfaction

Sensing their environment is a crucial ability of all life forms. In higher eukaryotes the sensing of airborne volatile compounds, or olfaction, is well developed. In plants, slime moulds and yeast there is also compelling evidence that these organisms can smell their environment and respond accordingly. Here we show that bacteria are also capable of olfaction. Bacillus licheniformis was able to sense airborne volatile metabolites produced by neighbouring bacterial cultures and cells could respond to this chemical information in a coordinated way. When Bacillus licheniformis was grown in a microtitre plate adjacent to a bacterial culture of the same or a different species, growing in complex medium, biofilm formation and pigment production were elicited by volatile molecules. A weaker response occurred in increasingly distant wells. The emitted volatile molecule was identified as ammonia. These data demonstrate that B. licheniformis has evolved the ability collect information about its environment from the surrounding air and physiologically respond to it in a manner similar to olfaction. This is the first time that a behavioural response triggered by odorant molecules received through the gas phase is described in bacteria.     

Plant‐extract‐induced changes in the proteome of the soil‐borne pathogenic fungus Thielaviopsis basicola

Thielaviopsis basicola is a hemibiotroph fungus that causes black root rot disease in diverse plants with significant impact on cotton production in Australia. To elucidate how T. basicola growth and proteome are influenced by interactions with natural sources, this fungus was cultured in the presence of root extracts from non‐host (wheat, hairy vetch) and susceptible host (cotton, lupin) plants. We found that T. basicola growth was significantly favored in the presence of host extracts, while hierarchical clustering analysis of 2‐DE protein profiles of T. basicola showed plant species had a larger effect on the proteome than host/non‐host status. Analysis by LC‐MS/MS of unique and differentially expressed spots and identification using cross‐species similarity searching and de novo sequencing allowed successful identification of 41 spots. These proteins were principally involved in primary metabolism with smaller numbers implicated in other diverse functions. Identification of several “morpho” proteins suggested morphological differences that were further microscopically investigated. Identification of several highly expressed spots suggested that vitamin B₆ is important in the T. basicola response to components present in hairy vetch extract, and finally, three spots, induced in the presence of lupin extract, may correspond to malic enzyme and be involved in lipid accumulation.     

研究生生物化学课程教学改革的尝试

针对化工和轻化工专业研究生生物化学的教学特点,从教学方法、教学内容和教学手段上进行了一些改革和尝试。     

原子力显微镜在微生物学领域的应用*

原子力显微镜是揭示微生物表面结构及其与功能相关性的一种新的有力的工具,它具有比传统电子显微镜更高的放大倍数和极高的分辨率,能对从原子到分子尺度的结构进行三维成像和测量,并且可以在生理条件下实时进行。因此,原子力显微镜越来越多地应用到微生物学的各个方面,并且取得了许多令人鼓舞的结果。     

医学研究生临床生化专题全英教学的改革与实践思考

为培养高质量国际化有才能的医学研究生,对于已经学习过生物化学的国际医学留学研究生,开展了以与临床密切相关的生物化学专题为主要教学内容的全英文授课的教学实践和课程建设,取得了很好的教学效果.临床生化专题全英教学课程也可能适用于国内生物化学和医学相关专业的研究生,在今后的教学实践中需要继续研究和探索,以提高国内医学相关研究生的专业综合素质.     

生物化学教学中采用案例教学法之案例设计与分析

案例教学法是被普遍采用的一种教学方式,将其应用于生物化学教学中,并用图解的形式给出案例的归纳与分析,使抽象难懂、错综复杂、生涩冷僻的教学内容变得直观明了。加深了学生对教学内容的理解,增强了课堂教学的趣味性与学生学习的主动性,同时提高了学生分析问题和解决问题的能力。     

蛋白质纯化虚拟仿真课程的教学设计

目的 蛋白质纯化是医学与生物学实验教学课程中的一个重要内容，本文通过设计新的蛋白质纯化虚拟仿真教学内容，开发虚拟仿真教学系统，希望学生能够更有效率地掌握蛋白质纯化技术的要点，提升教学质量。方法 利用3D虚拟仿真技术，构建虚拟仿真实验室。结合线下教学经验，确定虚拟仿真教学中需要体现的教学内容、教学重点、核心仪器的特色、评分指标、考核方式、操作体验等。结果 本文基于3D虚拟仿真技术构建了蛋白质纯化虚拟仿真实验室，和传统教学相比，虚拟仿真教学可以提高教学效率，节省教学成本和场地占用；教学设计和虚拟仿真教学系统融合了教学、练习和考核模块，根据以往的教学经验优化了评分体系，保证学生更加有效、严谨地掌握技术细节；涵盖了全新的教学内容——荧光检测联用的分子排阻层析，添加了蛋白质层析的常用案例，保证了内容的新颖与实用；完全再现了现实实验室中仪器设备的搭建模式，实现虚拟学习与实际操作的无缝衔接。结论 蛋白质纯化虚拟仿真教学系统由虚及实，由点及面，把控细节，保证学生动手能力和探索能力的提高，学以致用，并且拥有传统教学模式不可比拟的优势。     

遗传学实验（十五）两倍体细胞株培养

实验原理 组织培养是把动物或植物细胞自机体取出放在玻 璃器皿里,选择和控制某些外界条件,使细胞继续分裂 生长的一种基础性实验技术;现在已广泛应用于生理 学、免疫学、病毒学、遗传学等方面,对细胞分化、发育、 肿瘤发生以及染色体研究等领域起着很大的作用。     

Protein expression changes induced in murine peritoneal macrophages by Group B Streptococcus

Protein expression changes induced in thioglycolate‐elicited peritoneal murine macrophages (MΦ) by infection with type III Group B Streptococcus (GBS) are described. Proteins from control MΦ and MΦ incubated 2 h with live or heat‐inactivated GBS were separated by 2‐DE. Proteins whose expression was significantly different in infected MΦ, as compared with control cells, were identified by MS/MS analysis. Changes in the expression level of proteins involved in both positive and negative modulation of phagocytic functions, stress response and cell death were induced in MΦ by GBS infection. In particular, expression of enzymes playing a key role in production of reactive oxygen species was lowered in GBS‐infected MΦ. Significant alterations in the expression of some metabolic enzymes were also observed, most of the glycolytic and of the pentose‐cycle enzymes being down‐regulated in MΦ infected with live GBS. Finally, evidence was obtained that GBS infection affects the expression of enzymes or enzyme subunits involved in ATP synthesis and in adenine nucleotides interconversion processes.