Virtually all animal cells contain organelles called glycosomes which until now have been neglected in cell biology. This author recently published a comprehensive review article entitled "Glycosomes - the organelles of giycogen metabolism", Tissue & Cell 28 (3) 253-265, 1996. The review, based on biochemical and microscopy data, includes a complete history of giycogen research and the current status of knowledge

Biochemical studies on giycogen metabolism demonstrate the existence of a complex enzymatic machinery involved in giycogen synthesis and degradation, which constantly accumulates giycogen and releases glucose. Such types of cellular machineries represent cell organelles and these were already called glycosomes.

Science educators in K-12 schools are often confronted with skepticism when the budgetary needs for equipment and materials come up for discussion. They are expected to make science “interesting”, “exciting”, “motivating”, and “up-to-date”, but without investing money in modern technology. It is important to not let this common fascination with novelty, excitement and parsimony, prevent us from realizing the full potential for videomicroscopy in classroom science teaching. In addition to their “gee, whizl” aspects, videomicroscopes offer a number of instructional advantages that make them worth the money, and I will present some ideas about how to use and configure a videomicroscope for classroom use.

Start with a handbook of chemistry and physics, In the tables of physical constants will be listed the metals solubilities in various acids. Pick an appropriate acid, and as a first try use 10% acid in methanol (a good electrical conductor). Ethanol is less conductive and more viscous than methanol. Always check chemical safety before starting. Never mix nitric acid with ethanol, for example; it explodes above a 5% concentration. Chill the solvent to at least 0° C before adding acid.

In the past, I have used mountants such as DIATEX (which is a synthetic mountant of 40% acrylic resin solids, and 60% toluene), or Canada Balsam in xylene for general purpose mountants. If a tight seal of resin forms around the coverslip, the prep is usually good for some time and may last indefinitely. However, the center of the prep still contains resin mixed with solvent that has not had a chance to evaporate, If the solvent continues to evaporate slowly from the prep, large air bubbles will replace the solvent and ruin the prep.

In my 20 plus years of experience, I have found that nearly every specimen contaminates to some degree (some slower, some faster) in an electron microscope regardless of the manufacturer. Most of this contamination comes from the specimen, and it's magnitude is a function of the sample (metallic, semiconductor, organic, etc.), the method of preparation (electrochemical chemical, microtoming, ion milling, etc.), the microscope conditions, the probe and probe current - plus a number of less well controlled factors. Reactive gas plasmas can fortunately be used to mitigate the contamination process and frequently reduce the problem to negligible levels. Basically, one places the specimen/stage in a “tow energy plasma” where the gas acts like a catalyst for a localized surface chemical reaction, The energy of the plasma breaks weak bonds of the hydrocarbon compounds on the surface which then make these species somewhat volatile so that they can further react with the gas in the plasma.

The planarizing technique of materials lapping and polishing shows many benefits in providing samples for optical microscopy in failure analysis, quality control and related fields. A method is described below which provides both rapid and accurate micro-sections of pcb's, wafers, packaged components and other processed materials, with the use of a novel approach involving a 'calibrated' polishing base and a 'Micropositioner' head. Other benefits include the ability to halt material removal at a predetermined process endpoint and convenient sample mounting techniques.

There is a considerable body of information of a technical and review nature on negative staining elsewhere in the literature (Bremner et al., 1992; Harris and Home, 1991, 1994; Hayatand Miller, 1990; Holzenburg, 1988; Home, 1991; Nermut, 1991; Spiess et al., 1987; Valentine and Home, 1962); therefore, I shall attempt to avoid undue repetition and present the current laboratory approaches with which I am personally familiar and have achieved some technical success. After considering the range of procedures necessary for the production of carbon and carbon-plastic support films (sometimes termed substrates) emphasis will be placed upon the droplet negative staining technique (Harris and Agutter, 1970; Harris and Horne, 1991). I was introduced to this approach by Ennio Lucio Benedetti in his laboratory, at the start of my doctoral studies in 1966 (Anderson, 1966; Benedetti and Emmelot, 1965,1968) and with minor variations it is still useful for many biological applications.

Advances in the biological sciences have given rise for the need to visualize microscopic structures of interest. As the requirement to see specific structure and sub-resolution details arise, investigators have turned to fluorescent probes to label and observe these details, which are often undetectable using conventional methods in light microscopy. Fluorescence microscopy offers many advantages for visualizing specific structure and sub-resolution details, which are often undetectable using transmitted light microscopy. Recent advances in fluorescent probe and microscope design, as well as imaging instrumentation designed for fluorescence applications, are now permitting life-science researchers to view details in regions of interest with increasing precision, accuracy, and resolution.

Notwithstanding the importance of trees, considerable technical problems have severely restricted study of the fine structure of the vascular cambium and the wood and bark that it produces. And despite the advent of immunocytochemical techniques, it is only in the last few years that the roie of the cytoskeleton in the process of secondary vascular differentiation has been studied. Yet, for those who persist with this intractable material, the experience can be rewarding. This article discusses the difficulties involved in microscopy of this material, and offers some solutions.

A scanning acoustic microscope (SAM) - a nanomicrophone using a piezoelectric crystal, may be used to examine bacterial colonies, not just materials specimens to detect phonons and listen to propagating microfractures.

Since bacterial cell walls are rigid structures, they undergo mechanical distortions when channels open and dose. This causes them to squeak and pop, each channel having its own sound. Channels and receptor molecules are all of different sizes and shapes, and therefore deform the cell wall in unique ways. This means that each channel makes a unique (if faint) sound when it passes a molecule through itself and this activity can be delected, Transport rates of uptake and excretion for the various compounds car then be calculated trom the intensity of the sounds.

Whether they need Chinese language flash cards, steps and music to a Scottish country dance, physics simulations, or any one of hundreds of other teaching tools, educators and researchers can find them at Apple's Educational Object Economy (EOE) project (http://trp.research.apple.com).

The EOE is a complementary online community based around the creation, sharing, and use of teaching resources that incorporate Java applets for web-based learning. Java applets are small, easy-to-use programs written in Sun Microsystem's Java programming language. Using virtually any computer equipped with a standard web browser, educators can access hundreds of teaching and curriculum development tools for use in the classroom, for research, or in other educational endeavors.

Secondary (SE) and backscattered electron (BSE) signals in the SEM provide high resolution monochrome images. BSE signal strength is modulated by mean atomic number and ‘false” colour can be introduced to enhance material contrast. Colour can also be introduced using multiple SE detectors, each with a different sensitivity to topographic and compositional information: by controlling signal mixtures and colours, the operator effectively has access to a powerful “studio” to generate aesthetically pleasing colour images. In both these examples, the correspondence between local elemental content and colour is entirely arbitrary and under subjective control of the operator, Elemental x-ray maps can be acquired and combinations colour coded to reveal phase distributions. For large numbers of maps and images, chemometric techniques such as PCA may be used to discover common relationships and assist the process of colour coding. Images derived from x-ray maps are usually low resolution and the analyst has to decide which elements to include and do a fair amount of data manipulation before any conclusions can be drawn.

Improvements over the past few years in essentially all modern operating systems coupled with the blurring of the boundaries between mainframes, workstations, and personal computers make the choice of platform often one of personal preference other than of necessity. A decade ago there were very distinct differences between the features offered by IBM PC and clones, the Apple Macintosh, and UNIX workstations. These differences included price, processing performance, OS features, look and feel, graphical capabilities, memory and disk limitations, networking capabilities, ease of- use, system stability, development tools, etc. Since then many of these distinguishing differences have evaporated making platform selection a more subtle issue, but also much less important. However, there are still a great many users thai tend to make such decisions based on their “religious” preference of platform rather than based on objective information.

As the dawn of the next millennium approaches, the light microscope enters its fifth century of use, while the personal computer barely enters its third decade.

When Antony van Leeuwenhoek peered through his self made hand crafted microscope and documented the first observations of bacteria and cells, much of microbiology and cell biology was born. When the personal computer became a tool in modern science, molecular cell biologists were well into the age of human genetic engineering.

While the rise and acceptance into scientific importance of the microscope and the personal computer represent vastly different periods of sophistication in modem science, the combination of these two important scientific tools for computer aided microscopy (CAM) clearly provides bold uncharted potentials and opportunities for medicine, biomedical research, and industry in the future century to come.

Service contract expenses constitute a large proportion of many EM laboratory budgets each year and managers, under constant pressure to reduce costs, no longer look at the expense as sacred. Increasingly, microscopists are faced with finding alternatives to the full service contracts they enjoyed so long. I facilitated a discussion group at the Microscopy & Microanalysis '97 meeting held recently in Cleveland entitled "EM Maintenance: Can you do it yourself?" The audience of 50 represented microscopists from industry, academic and government facilities with a common interest - learning how to sensibly reduce service contract costs. In this article, I will offer my perspective on the subject and relate issues raised by the audience.