Parkinson's disease is a progressive disorder that is characterized by degeneration of the dopamine containing neurons located within the midbrain (substantia nigra). There is also substantial loss of dopamine within nerve terminals located within the striatum which originate from those dopamine neurons. Current therapy involves administration of the precursor to dopamine, namely l-dopa. This chemical is taken up into the brain and then converted to dopamine. Although replacement of dopamine is effective over the first few years, other movement disorders are associated with longterm l-dopa therapy. The l-dopa induced dyskinesias limit the usefulness of this type of therapy.

Although loss of dopamine is the major neurochemical deficit in Parkinson's disease, other neurotransmitters within the striatum may also be altered. There is a major axonal projection from the cortex to the striatum. The corticostriatal pathway uses the excitatory neurotransmitter, glutamate, and dopamine is known to modulate the activity of glutamatergic synapses

Repeated intermittent administration of cocaine to rodents has been shown to result in behavioral sensitization, or enhanced locomotor activity. Because there are similarities between effects of intermittent cocaine use in humans and sensitization in rats, understanding the neural mechanism underlying sensitization may provide insights into mechanisms of psychopathologies in humans.

There is abundant evidence that the mesolimbic dopaminergic pathways, originating in the ventral tegmental area (VTA) and terminating in both nucleus accumbens (NAc) and prefrontal cortex (PFC), are critically important for development of sensitization to the motor-stimulating effects of cocaine. Evidence also suggests that changes in glutamate (Glu) transmission in the mesolimbic DA pathways are associated with sensitization to cocaine. In recent collaborative studies, we have shown that cocaine administration transiently decreases the density of nerve terminal glutamate immunolabeling within the NAc shell following withdrawal from continuous or intermittent cocaine administration. Locomotor activity was not assessed in either of these studies.

The eye offers the unique possibility of direct visualization of microvessels in readily accessible tissues. Due to the compact anatomy of the eye, different microvascular beds of different embryological origin can be examined in albino mice without traumatic tissue preparation, Epifluorescence microscopy in combination with different fluorescent dyes has been applied. To observe individual cells in vessels, rhodamine 6G can be used to stain leukocytes and platelets, and acridine orange stains nuclei of leukocytes and endothelial cells. Fluorescein-isothiocyanate (FITC)-dextran labels plasma.

Iris, limbus, conjunctival and choroidal vessels under normal and inflammatory conditions (endotoxin-induced uveitis) were examined in BALB/c mice and Lewis rats. Digital video technology can be applied to intravital microscopy with great benefit: video quality remains on a high level and the amount of time for the quantification procedure and the need of expensive software is reduced compared to classical video recording.

Pericytes are cells of mesodermal origin that intimately surround most types of blood capillaries as well as postcapillary venules and precapillary arterioles (smooth muscle cells are found in the walls of larger vessels). Although abnormalities of capillary endothelial cells have been described in diseases such as diabetes, arterial hypertension, autoimmune inflammatory myopathies and also in the paraneoplastic phenomenon, much less is known about morphology of pericytes and its implications in the microvascular structure in cancers, particularly those arising in the gastrointestinal tract. In this work we report the pericyte ultrastructural pathology in human gastrointestinal adenocarcinomas.

Surgically resected specimens from areas of tumor center and periphery were obtained from thirteen patients (seven females and six males) between 44 and 76 years of age (mean 61.92 years), with a histopathological diagnosis of gastrointestinal adenocarcinoma. Immediately after resection, tissue samples were processed by routine transmission electron microscopy techniques and observed in Hitachi H-500 and H-7100 electron microscopes.

The Derm Imaging Center uses various light and electron microscopic techniques to determine meaningful morphologic differences in skin samples received from multiple investigators. Qualitative comparisons required laborious hand measurements, which, in time gave way to computer assisted image capture, enhancement and analysis. The ability to attach a numerical value to a morphologic observation has made quantification an expected component of the experimental results. Laboratory personnel are now spending more time in front of computers than microscopes. This fact prompted a reevaluation of our current methods resulting in a faster, user-friendly computer assisted imaging system.

One software program that has become ubiquitous within the field of scientific imaging is Adobe® Photoshop®. Although a multitude of different image capture and analysis software programs are in use, a version of Photoshop® can invariably be found residing in most laboratories involved in imaging. A disadvantage of many image analysis software programs is the lack of image enhancement capability that we have grown to know and love within the Photoshop® environment.

Old-growth Douglas-fir trees in the Pacific Northwest are venerable giants that often live for 500 years and reach heights of over 75 meters. Their needles are relatively ephemeral and small but have the important role of interacting with the atmosphere in order to transpire and photosynthesize. Within the photosynthetic mesophyll tissue of Douglas-fir needles, there are large, non-living cells with lignified secondary cell walls that are known as astrosclereids. Apparent channels in the secondary wall may provide a route for exchange or transport of materials between the astrosclereid lumen and mesophyll cells or the vascular cylinder. Astrosclereids may be involvev d in storage of secondary metabolites such as tannin and may develop in response to fungi, mistletoe, or other pathogens. More knowledge is needed about the development, structure and function of astrosclereids.

Needles were collected from sapling and old-growth Douglas-fir, Pseudotsuga menziesii, (Mirb.) Franco, trees at the Wind River Canopy Crane in Carson, Washington and from three sites in the Cascade Mountains of Oregon in 1997 and 1998.

Lyme disease is a tick borne, multi-system disorder caused by low density systemic infections with the spirochete Borrelia burgdorferi. Without antimicrobial treatment, mammalian infections with these bacteria are persistent and chronic. Recent studies showed that B. burgdorferi can target, invade, and lyse both cultured and primary human B and T cells. Direct interactions between the spirochetes and lymphocytes also leads to adherence of B and T cell antigens on the surface of significant proportions of the bacteria . Adherent lymphocytic antigens inhibit binding of antibodies to prominent B. burgdorferi proteins, and interfere with classic complement-mediated killing, suggesting a possible role for spirochete-lymphocyte interactions in immune evasion.

In order to develop an experimental animal model for assessing spirochete-lymphocyte interactions, B. burgdorferi and primary mouse lymphocytes were co-incubated and examined by electron microscopy. Mononuclear cells were separated from fresh mouse blood by Ficoll gradient centrifugation (ICN, Biomedicals, Aurora, Ohio).

Organisms found at the Air-Water Interface (AWI) are often difficult to collect and usually show distortion upon collection and fixation by traditional methods. Furthermore, the spatial relations between the organisms and the complexity of their biofilm community is disrupted or destroyed by collection methods that involve bulk water collection, filtration, settling or rotating drums. Samples shown here were collected on the Tualatin River, Oregon, a eutrophic rural/suburban stream with welldeveloped Aquatic Surface Films (ASF or Microlayers) in quiet waters.

Here, I describe a simple method of collection for Aquatic Surface Films (Microlayers), by drawing a glass substrate slowly through the surface film, allowing both organic chemicals and small organisms to adhere to the surface of the glass. This is similar to the collection of a Langmuir-Blodgett film, and it has been proposed that chemical and biological films at the surface might allow this type of collection.

AGL15 (AGAMOUS-like 15) was originally identified as a sequence preferentially expressed in developing plant embryos by comparing PCR-generated ‘differential displays’ of embryo and non-embryo RNA populations. The sequence is expressed at low levels and encodes a member of the MADS domain family (named for the first four members to be identified: MCM1, AGAMOUS, DEFICIENS, and SERUM RESPONSE FACTOR) of regulatory factors. Members of the MADS domain family play pivotal roles in critical developmental events in a wide variety of organisms: in specification of mating type in yeast (MCM1), in responses to the environment in human cells (SRF), in control of mesoderm differentiation in Drosophila and muscle differentiation in humans (MEF2), and in determination of meristem and organ identity during flower development in plants (AGAMOUS, DEFICIENS/APETALA3, GLOBOSA/PISTILLATA, etc.). AGL15 is the only MADS domain factor identified to date that is expressed in a highly preferential manner in plant embryos.

The mechanism of cytokinesis in higher plants is distinct from that of animal and yeast cells. Dividing plant cells are separated by the de novo construction of the cell-plate across the inside of the cell. Assembly of this new organelle is directed by a specialized cytoskeletal structure called the phragmoplast, a unique macromolecular scaffold that appears late in mitosis and is composed of intermediate filaments, microfilaments, and microtubules. Secretory vesicles are guided along the phragmoplast cytoskeleton toward the equatorial region of the structure where they coalesce and fuse to form a membranous tubular-vesicular network within which cell wall biosynthesis is initiated. A smoother more plate-like structure develops and extends radially outward as additional vesicles are added to the growing margin of the cell-plate until it ultimately fuses with the parental plasma membrane yielding two daughter cells separated by a common cell wall and extracellular space.

The Ascochyta blight caused by Ascochyta rabiei ( Pass.) Labr. is a serious foliar fungal disease of chickpea (Cicer arientinum L.). The histo- and cytopathological examination of hostpathogen interactions was conducted in resistant ( ELC-195) and susceptible (Canitez-87) cultivars of chickpea at 3, 5, 7 days after inoculation with A. rabiei. Several histological studies have been made with A. Rabiei. No ultrastructural studies comparing the resistant and susceptible reactions of chickpea to A. rabiei have been reported.

The hypersensitive response (HR) is a very common reaction in resistant chickpea plants challenged with A. Rabiei. The FfR has also been associated with defence reactions which is phytoalexin synthesis. Phytoalexins are compounds, synthesised in host plant cells, after infection, which have antimicrobial properties. Fligh concentrations are often found in nearby necrotic cells which prevents further growth of the A. Rabiei in resistance chickpea.

A. rabiei produce typical appressorium formation for cuticle penetration but stomata penetration have been observed in some micrographs (Fig.l).

Leaf senescence is an orderly, active process in which nutrients in a leaf are reclaimed and mobilized to other parts of the plant. It is considered to be the final stage in leaf development. During senescence leaves undergo highly coordinated changes in cell structure, metabolism, and gene expression. For example, chloroplasts undergo obvious structural modifications during leaf senescence. Regarding gene expression, genes with steady-state mRNA levels that increase during senescence are often referred to as senescence-associated genes, or SAGs.

In order to study ultrastructural changes that occur during senescence, portions of fully expanded, mid-senescent, and fully senescent Arabidopsis thaliana leaves were chemically fixed using vacuum-accelerated microwave processing. Thin sections were observed for ultrastructural changes such as development of transfer cells that are characterized by the presence of cell wall ingrowths. Transfer cell development is correlated with an increased capacity of tissues to take up materials, related partly to an increase in plasma membrane surface area.

Poly-β-hydroxybuterate (PHB), a biodegradable polyester, is accumulated as a storage compound in many species of bacteria. It belongs to a class of polymers called polyhydroxyalkanoates (PHAs). PHA's were originally identified in 1923.However these polymers first came to the attention of industry in the early 1980's when they were recognized as having thermoplastic properties.Monsanto currently markets a form of PHA produced via fermentation under the trade name Biopol™. It is used to make biodegradable plastic products such as credit cards, bottles and disposable drinking cups. However fermentation is an expensive route to production. The use of crop plants genetically engineered to produce PHA's could provide a less expensive source of the plastic and therefore a more attractive alternative to traditional non-biodegradable petrochemical derived plastics. PHB production in plants was first demonstrated in 1992 in transgenic Arabidopsis thaliana by Chris Somerville and coworkers. They showed that PHB production was tolerated by the plant if it was targeted to the chloroplasts.

Potamogeton pectinatus is a submerged halophyte which occurs in waters of low salinity (5% to 10%). Its upper salinity tolerance has been reported to be 19%. Reasons why P.pectinatus is unable to tolerate salinities in excess of 19%is important to our understanding of its biology. In the present study, leaf ultrastructure of plants growing at low salinity was compared with plants growing at high salinity in order to assess the effects of different salinities on the ultrastructure. Attention was focussed on ultrastructural changes occurring in the leaf epidermis, the main photosynthetic tissue.

Plants were grown in seawater at two salinities : 5%(low salinity) and 20% (high salinity). Pieces of mature leaf blades from both treatments were harvested and prepared for Transmission Electron Microscopy (TEM) following standard procedures. The overall distribution and concentration of chlorine (CI) in the leaves was ascertained since this element is the most abundant anion in seawater and is important in considerations of salt tolerance in submerged halophytes.

Understanding the light-harvesting properties of algae and higher plants are a fundamental topic in photosynthesis research. Much oceanographic research has focused on characterizing the in vivo chlorophyll-specific absorption coefficient, a*ph (λ) in phytoplankton because it serves as an input variable for bio-optical modeling of photosynthesis using remote sensing instrumentation such as moorings, drifters, and satellites. Values of a*ph (λ) vary spectrally and the magnitude depends on accessory pigments, photo-protective pigments, and pigment packaging effects. Several studies have shown that the contribution of cellular characteristics to a*ph(λ) varies with growth conditions including temperature, light, and nutrients. It has been shown that a*ph (λ) values in Phaeocystis vary predictably at 4°C over light intensities under light limitation. Phaeocystis demonstrated significant pigment package effects that depended on single cell diameter and thylakoid membrane stacking. Using thick sections obtained from fixed and embedded cultures of colonial P. antarctica, we calculated tomographic reconstructions of individual chloroplasts under light-limiting conditions for net photosynthesis in order to gain an understanding of the continuity of thylakoid membranes and understand the spatial relationship between the pyrenoid, the starch containing organelle, and thylakoid membranes.

The ability to visualize the chromosomes, especially in three-dimensional (3D) space, has great benefits for the understanding of genes’ function. The availability of various trisomic genotype in maize provides an excellent system for the study of 3D chromosome arrangement at various developmental stages. Laser scanning confocal microscopy and digital deconvolution technique is best suited for this type of work. A preliminary database on the three-dimensional arrangement of Ohio43 inbred line has been established; this information is essential for the evaluation of the effect of additional chromosome in trisomy genotypes.

Tassel inflorescence of maize (Zea mays L.) trisomy 6 in Ohio43 background were collected from the field station at the University of Western Ontario in London, Ontario, Canada, during the summer of 1998. Tassels at the proper developmental stages were fixed in 3:1 (95% EtOH / acetic acid) solution and stored at room temperature. After dissection from the spikelet, anthers were treated with the Feulgen-method, dehydrated in ethanol series and cleared in methyl salicylate.

Visualization is interdependent with gene mapping and DNA sequencing, because spatial relationships are important to understand function. The ability to visualize the chromosomes, especially in threedimensional (3D) space, has great benefits for the better understanding of a gene's function. For these reasons, a better technique is needed to study the chromosomes in 3D. Studying the stages of meiosis I provides an excellent opportunity to evaluate the capability of 3D imaging techniques. The loosening of the chromosomes in meiosis I exemplify the advantages of 3D imaging.

Tassel inflorescence from maize (Zea mays L., inbreed Ohio43) was collected from the field station at the University of Western Ontario in London, Ontario, Canada during the summer of 1998. Tassels at proper developmental stages were fixed in 3:1 (EtOH / acetic acid) solution. The anthers were stained with the Feulgen method and cleared in methyl salicylate.

Polychlorinated biphenyls (PCBs) are ubiquitous environmental contaminants that bioaccumulate in the food chain and thus pose a health risk to human beings and other animals. The exceptional dielectric and lubricating properties of the PCBs resulted in their extensive use during the mid-1950s as lubricants in electrical generators and transformers. PCBs have a long half-life and persist in the environment causing concerns related to their toxicity. The present research on congener 118 (2,3',4,4',5-pentachlorobiphenyl) involves the quantification of hepatocyte alterations using stereology techniques. Application of a quantitative technique to estimate liver pathology confers more confidence in evaluating toxicity of a xenobiotic, and in the determination of its NOAEL (No Observable Adverse Effect Level).

Alterations in the volume fraction of cellular constituents in the hepatocytes induced by congener 118 were estimated relative to the sex of, and dose fed to a laboratory population of weanling Sprague-Dawley rats. The rats were given the PCB dose in concentrations of 2, 200, and 2,000 ppb to females and 10, 1,000 and 10,000 ppb to males; three animals were used in each dose group.

Immunocytochemistry studies have established that multivesicular bodies (MVBs) in alveolar type II epithelial cells are important for processing pulmonary surfactant protein precursors (proSP; Voorhout et al., 1992 and 1993). Localization of pulmonary surfactant protein A (SP-A) gold and cationic ferritin to the MVBs demonstrated that MVBs also serve as endosomal/lysosomal compartments for recycling SPs (Williams et al., 1984, Ryan et al., 1989). However, these studies did not elucidate whether the biosynthesis of pulmonary SPs and endocytosis occur in the same MVBs. In this study, we used primary murine alveolar type II epithelial cell cultures as a model to determine if the biosynthetic and endocytic compartments colocalized in MVBs. The endocytic compartments of MVBs were identified using BSA gold conjugates, while the biosynthetic pathway was detected with antibodies directed against proSPs.

Alveolar type II epithelial cells isolated from 6 weeks old C57B/6 mice were grown on Transwell cell inserts in the presence of 6 nm BSA gold conjugates (BSAG6) adjusted to final concentration of OD520 5.0 in DMEM, 25 mM HEPES, and 10% fetal bovine serum, pH 7.3, at 37 °C for 20 hours.

Tamoxifen and taxol are two promising chemotherapeutic agents currently used in cancer treatment, but each has its own unique mechanism of action. Tamoxifen, known to inhibit the activity of estrogen on malignant mammary gland cells, was recently approved by the FDA for the treatment of breast cancer. Taxol, extracted from the Pacific Yew tree, Taxus brevifolia, is an antimitotic agent that binds specifically to the β-subunit, promoting the assembly and stabilization of tubulin polymers. Studies have shown that tamoxifen and taxol induce cytostatic and cytotoxic effects leading to the death of several cancer cell types in vitro.In this research, the surface ultrastructural effects of both tamoxifen and taxol were investigated in human cervical cancer cells (HeLa).

Exponentially growing cells were treated with 5, 10, 15, and 20 μg/ml of tamoxifen and 1 μg/ml of taxol (LC50) for 24, 48, 72, and 96 hours. For scanning electron microscopy (SEM), the cells were grown on coverslips, fixed in 2% glutaraldehyde followed by 1% osmium tetroxide.