Gene expression has been visualized for a few decades, but in static forms such as blots and gene chips. Susan Janicki, Toshiro Tsukamoto, Sim one Salghetti, William Tansey, Ravi Sachidanandam, Kannanganattu Prasanth, Thomas Ried, Yaron Shav-Tal, Edouard Bertrand, Robert Singer, and David Spector have recently designed a cell line in which gene expression can be observed with stunningly accurate spatial and temporal resolution. Gene expression is a cascade of events beginning with transcription of RNA from the DNA template and ending with translation into a protein sequence. Janicki et al. were able to visualize the entire process at the levels of DNA, RNA, and proteins in living cells!

Plants that are used for taxonomic research are generally preserved by drying them out while they are being pressed flat for easy storage. This pressed plant material, is placed in a herbarium, in phylogenetic order, based on the species, genus, family and order designations.

Herbaria are essential for the study and verification of plant classification, the study of geographic distributions, and the standardizing of taxonomic nomenclature. Lately, herbarium materials have been utilized in biochemical and genetic studies. The key to these studies is the state of preservation of the plant material. The preservation of the reproductive and vegetative structures (hairs, stomata, cuticle, etc.), internal anatomy (vascular tissue size and arrangement), biochemistry and genetic material is essential to make accurate observations, to collect representative data and answer pertinent research questions.

By using a scanning transmission electron microscopy (STEM) detector, the information limit for the Gemini® FESEMs can be extended beyond the nanometer range. A resolution of 0.8 nm at 30kV is now readily attainable and gives additional nanoscale information compared to conventional SEM detectors. The resolving power of the combined FESEM/STEM can be used to save processing time on TEM systems and enables high sample throughput for quality assurance applications and standard type measurements. The transmission mode of the FESEM has the advantages of avoiding chromatic aberration, allowing for a larger aperture so that higher transmission, signal-to-noise ratio and contrast enhancement due to the lower electron energy (10 - 30kV) can be obtained.

Although many samples in electron microscopy are phase objects, as in the case of optical microscopy, we cannot directly measure phase modulation by microscopy. Dennis Gabor proposed a technique called in-line holography to record both amplitude and phase information at the rather early stage of electron microscopy (in 1947). With the development of highly coherent field emission electron sources, another type of holography, off-axis holography, became available for electrons. However, holography cannot be applied to general cases, since there is a requirement for a vacuum region where the reference wave passes through.

All living creatures, including humans, are made of cells. The majority of life forms exist as single cells that perform all functions to continue independent life. Some cell structures, cell organelles and particularly bacteria and viruses are commonly too small to be fully observed with an optical microscope. Therefore, an electron microscope is required. Since samples examined with an electron microscope are exposed to very high vacuum, it is impossible to view living cells. The sample preparation for electron microscopy requires that living cells be killed, frozen, dehydrated, and impregnated with heavy metals.

Materials research, biomedical research, and semiconductor manufacturing can all benefit from nondestructive, high-resolution methods of analysis. As most materials are heterogeneous, it is important to not only acquire high resolution topographic information, but also to identify the chemical composition of samples. A combination of high resolution microscopy with chemically sensitive spectroscopy combined in one instrument allows the detailed characterization of samples with different analytical techniques. When individual instruments are used, returning to a previously surveyed sample area can be very time consuming if not impossible without surface markers.

In order to achieve a three dimensional appearance to a pair of two dimensional images, two off-axis images can be produced and colorized. These can be overlayed slightly apart and then viewed through glasses with two differently colored sides, one color for the left eye and another for the right eye in combinations containing red, green or blue colors. These off-axis and colorized images are referred to as anaglyphs.

Off-axis images can be achieved through the use of a tilting stage on a microscope, by physically changing the position of a camera in relation to a still object, or through changing the axis of an optical stack of sections, such as what is created by confocal/CT scans. Some images lend themselves more to a 3D look both by virtue of inherent three dimensionality limited by the resolution of the imaging system.

Historically, SEM developed as a high vacuum technique requiring sample chamber vacuum of 10-5 Torr or better. Energetic electrons scatter from any molecules they encounter, so their creation and transport from source to sample, through the focusing lenses of the electron column, requires high vacuum. This imposes a number of limitations on the kinds of samples that can be examined. Samples must tolerate the vacuum environment and the vacuum system must tolerate the sample. Generally, samples have to be solid, clean, dry, and not contain volatile components. Furthermore, since the vacuum insulates the sample from everything except the stub that supports it, non-conductive samples require a conductive pathway between the scanned region and ground to prevent the accumulation of charge deposited by the beam electrons.

In an optical tweezers system, the output signal of a photodiode quadrant detector and the temperature in a sample cell are two key factors for the quantitative measurements of mechanical properties of living biological objects such as cells, organelles and macro-molecules. In order to enhance the output of a quadrant detector and effectively control the temperature in a sample cell, the dependence of the temperature in the sample cell and the output of the quadrant detector for different illumination conditions are studied. The results show that appropriate illumination conditions can ensure both nearly constant temperatures in the cell and the desired output signal, which provides for the possibility of highprecision and damage-free analysis of living biological objects.

The microwave oven is a valuable tool for light and electron microscopy microtechnique labs. Tissue processing times, traditionally taking up to two weeks, have been reduced to a few hours as a result of the implementation of microwave technology (Kok et al., 1988, Gibberson and Demaree, 2001). In addition, the quality of the tissue preparations has improved dramatically. Microwave ovens have also evolved since their first use in the laboratory. Early experiments were conducted using relatively crude commercial microwave ovens. Now, labs use microwave ovens with temperature probes, strict control over the magnetron (which generates the microwaves), variable power supplies, chamber cooling, and high microwave field uniformity.

Raman spectroscopy, much like the more familiar infrared spectroscopy, reveals chemical information of materials under investigation as a result of molecular vibrations. The result of these techniques, the spectrum, is a chemical "fingerprint" allowing for material identification. While infrared microscopy is well known and well established in the industrial laboratory setting, Raman microscopy has only recently begun a resurgence as a result of technological advances. These include advances in lasers, optical filters (notch filters), and CCD detector technologies.

How do you give 1150 undergraduates in an introductory cell biology course (Biology 200) access to electron microscopes? Students often ask if they can see the electron microscopes. They often ask if they will have an opportunity to learn EM. As part of the course material, students are expected to recognize the images produced by different EM techniques, know the advantages and disadvantages of these techniques and interpret 2-dimensional micrographs in 3 dimensions. This is akin to teaching the theory of baking bread without ever smelling it in the oven. A pilot project was designed to address getting round the impossibility of bringing 1150+ students into the BioImaging Facility. This initiative gave selected undergraduates a hands-on experience of SEM in the BioImaging Facility and allowed the rest of their classmates to share that experience.