例析高中生物学概念的教学方法

结合生物学教学实际,总结了高中生物学核心概念教学的8种具体方法．即例证法、探究法、资料分析法、演绎法、归纳法、比较法、要素解析法和要领图法,并结合教学案例阐述每种概念教学方法的主要特征、活动经验及其实践应用。     

Molecular approaches to origin,ancestry and domestication history of crop plants: Barley and clover as examples

Knowledge of the origin and domestication history of crop plants is important for studies aiming at avoiding the erosion of genetic resources due to the loss of ecotypes and landraces and habitats and increased urbanization. Such knowledge also strengthens the capacity of modern farming system to develop and scale-up the domestication of high value potential crops that can be achieved by improving the knowledge that help to identify and select high value plant species within their locality, identify and apply the most appropriate propagation techniques for improving crops and integrate improved crop species into the farming systems. The study of domestication history and ancestry provide means for germplasm preservation through establishment of gene banks, largely as seed collections, and preservation of natural habitats. Information about crop evolution and specifically on patterns of genetic change generated by evolution prior, during, and after domestication, is important to develop sound genetic conservation programs of genetic resources of crop plants and also increases the efficiency of breeding programs. In recent years, molecular approaches have contributed to our understanding of the aspects of plant evolution and crops domestication. In this article, aspects of crops domestication are outlined and the role of molecular data in elucidating the ancestry and domestication of crop plants are outlined. Particular emphasis is given to the contribution of molecular approaches to the origin and domestication history of barley and the origin and ancestry of the Egyptian clover.     

Yeast systems biology: modelling the winemaker's art

Yeast research represents an important nexus between fundamental and applied research. Just as fundamental yeast research transitioned from classical, reductionist strategies to whole-genome techniques, whole-genome studies are advancing to the next level of biological research, referred to as systems biology. Industries that rely on high-performing yeast, such as the wine industry, are therefore poised to reap the many benefits that systems biology can provide. This includes the promise of strain development at speeds and costs which are unobtainable using current techniques. This article reviews the current state of whole-genome techniques available to yeast researchers and outlines how these processes can be used to obtain 'systems-level' information to provide insights into winemaking.     

Using non-radioactive probes on plants: a few examples

Due to costs in using and disposing of radiochemicals and to health considerations, we have been developing applications which include non-isotopic detection of DNA and proteins using chemiluminescence. Our major interests are in the detection of viral nucleic acids and in the analysis of transgenic plants. Generally, probes were labelled with digoxigenin, either by the random priming method or by PCR, and then detected with CSPD or CDP-Star. We routinely use a tissue blotting protocol for diagnosing TYLCV, a plant virus becoming a pest in the Mediterranean region. Test results were comparable with those using the same radiolabelled probe. When total nucleic acids are extracted from the plant samples and used in dot-blot or Southern blot assays, viral DNAs are promptly detected by chemiluminescence. In transgenic plants, chemiluminescence was used to detect the transgene on genomic Southern blots, the transgenic mRNAs on Northern blots, and the transgenic protein on Western blots. In Southern and Northern blots, the quality of the results obtained was usually satisfactory, but not as good as with a radiolabelled probe, the main problem being the signal-to-background ratio. Our goal is now to improve the quality of results in demanding applications such as genomic Southern blots, by reducing the background on membranes. © 1998 John Wiley & Sons, Ltd.     

Developmental biology of pterobranch hemichordates: history and perspectives

Hemichordates, like echinoderms and chordates, are deuterostomes, and study of their developmental biology could shed light on chordate origins. To date, molecular developmental studies in hemichordates have been confined to the enteropneusts or acorn worms. Here, we introduce the developmental biology of the other group of hemichordate, the pterobranchs. Pterobranchs generally live in cold, deep waters; this has hampered studies of this group. However, about 40 years ago, the colonial pterobranchs Rhabdopleura compacta and R. normani were discovered from shallow water, which has facilitated their study. Using Rhabdopleura compacta from south-west England, we have initiated molecular developmental studies in pterobranchs. Here, we outline methods for collecting adults, larvae, and embryos and demonstrate culturing of larvae under laboratory conditions. Given that the larval and adult forms differ from enteropneusts, we suggest that molecular developmental studies of pterobranchs may offer new insights into chordate origins.     

Agrobacterium-mediated genetic transformation of plants: biology and biotechnology

Agrobacterium-mediated genetic transformation is the dominant technology used for the production of genetically modified transgenic plants. Extensive research aimed at understanding and improving the molecular machinery of Agrobacterium responsible for the generation and transport of the bacterial DNA into the host cell has resulted in the establishment of many recombinant Agrobacterium strains, plasmids and technologies currently used for the successful transformation of numerous plant species. Unlike the role of bacterial proteins, the role of host factors in the transformation process has remained obscure for nearly a century of Agrobacterium research, and only recently have we begun to understand how Agrobacterium hijacks host factors and cellular processes during the transformation process. The identification of such factors and studies of these processes hold great promise for the future of plant biotechnology and plant genetic engineering, as they might help in the development of conceptually new techniques and approaches needed today to expand the host range of Agrobacterium and to control the transformation process and its outcome during the production of transgenic plants.     

Cell biology of protein misfolding: the examples of Alzheimer's and Parkinson's diseases

The salutary intersection of fundamental cell biology with the study of disease is well illustrated by the emerging elucidation of neurodegenerative disorders. Novel mechanisms in cell biology have been uncovered through disease-orientated research; for example, the discovery of presenilin as an intramembrane aspartyl protease that processes many diverse proteins within the lipid bilayer. A common theme has arisen in this field: normally-soluble proteins accumulate, misfold and oligomerize, inducing cytotoxic effects that are particularly devastating in the post-mitotic milieu of the neuron.     

Wavelets in bioinformatics and computational biology: state of art and perspectives

MOTIVATION: At a recent meeting, the wavelet transform was depicted as a small child kicking back at its father, the Fourier transform. Wavelets are more efficient and faster than Fourier methods in capturing the essence of data. Nowadays there is a growing interest in using wavelets in the analysis of biological sequences and molecular biology-related signals. RESULTS: This review is intended to summarize the potential of state of the art wavelets, and in particular wavelet statistical methodology, in different areas of molecular biology: genome sequence, protein structure and microarray data analysis. I conclude by discussing the use of wavelets in modeling biological structures.     

High hydrostatic pressure and biology: a brief history

Pressure as a thermodynamical parameter was successively introduced in physics, hydrometallurgy, geochemistry, and biology. In all cases, the main objective was to recreate a natural phenomenon (gas or liquid compressibility, synthesis or crystal growth of minerals, survival of deep sea microorganisms…). The introduction of high hydrostatic pressure (HHP) in Biology was an important scientific feature over the last hundred years. This paper describes the different steps that have led to the spreading of pressure in biology and the opening of new frontiers either in basic and applied researches due to the specific characteristics of the pressure parameter. Because of the low energy conveyed by this parameter, leading to the preservation of most organoleptic properties of foods, and its ability to inactivate many pathogens, the use of HHP began to spread at the end of the twentieth century into the food industry, in particular for the development of pathogen inactivation processes. Today, even if this field is still the first application domain for HHP, more and more research works have shown that this parameter could be of great interest in health and medicine sciences.     

The 1918 Spanish influenza: integrating history and biology

In 1918 an influenza pandemic killed 40 million people. It is now possible to study the genetic features of the 1918 virus. Such analyses will try to answer questions about the origin and the unusual virulence of this pandemic virus.     

Comparative biology of telomeres: Where plants stand

Telomeres are essential structures at the ends of eukaryotic chromosomes. Work on their structure and function began almost 70 years ago in plants and flies, continued through the Nobel Prize winning work on yeast and ciliates, and goes on today in many model and non-model organisms. The basic molecular mechanisms of telomeres are highly conserved throughout evolution, and our current understanding of how telomeres function is a conglomeration of insights gained from many different species. This review will compare the current knowledge of telomeres in plants with other organisms, with special focus on the functional length of telomeric DNA, the search for TRF homologs, the family of POT1 proteins, and the recent discovery of members of the CST complex.     

Mechanical loading history and skeletal biology

A comprehensive theory which relates tissue mechanical stresses to many features of skeletal morphogenesis, growth, regeneration, maintenance and degeneration is reviewed. The theory considers the repeated or intermittent mechanical forces which constitute the loading history on the chondro-osseous skeleton. The results of numerous mechanical stress analyses indicate that the local tissue stress history plays a major role in controlling connective tissue biology. The strong influence of mechanical energy in ontogenesis implies a comparably strong influence in phylogenesis. The fact that the mechanical stress histories in skeletal tissues are directly related to the force of gravity suggests that the life forms that have evolved on Earth are closely tied to our gravitational field.