Taxol has been used as anti-cancer compound against prostate, ovarian, and metastatic breast cancer. While the most obvious effect of taxol is bundeling of microtubules and mitotic arrest, recent studies have demonstrated that taxol is able to induce intranucleosomal DNA fragmentation and typical morphological features of apoptosis in a number of solid tumor cells. These results indicate that taxol may exert its anti-tumor effects via secondary mechanisms which may or may not be related to its primary effects on microtubules. It has been shown that taxol-induced microtubular changes and G2/M arrest are associated with the release of the electron transfer protein cytochrome C from mitochondria into the cytosol. Cytochrome C then binds to APAF-1 (a human homolog of the ced-4 gene of C. elegans), which binds, cleaves, and activates caspase- 9, ultimately resulting in the cleavage and activity of caspase-3. We investigated the effects of taxol (100nM) on microtubules, on DNA, and on the pre-apoptotic mitochondrial events using LNCaP and DU145 prostate cancer cells.

The usefulness of Differential Contrast Interference (DIC) light microscopy for observing fine details within transparent specimens is well known. However, when viewed by the eye or by recording with photographic emulsion, fine structural detail at the limit of resolution is often not visible because of lack of contrast. To overcome this problem, electronic contrast enhancement capabilities of video cameras have been used to enhance structural details that would otherwise be invisible. The technique, commonly referred to as VE-DIC (Video Enhanced DIC), uses first analog contrast enhancement of the image with a video camera followed by a real-time digital image processor to further enhance the image with. We are exploring the feasibility of achieving fine structural detail of live cells by directly acquiring digital images of them with a high resolution CCD camera.

High resolution cooled slow-scan 12-bit CCD cameras are well suited for DIC microscopy because of their greater dynamic range than video CCD cameras that are normally 8-bits or lower.

The active form of platelet derived growth factor (PDGF) is a polypeptide dimer of which there are three isoforms: PDGF-AA, PDGF-BB, and PDGF-AB. Furthermore, two types of PDGF receptors also exist: PDGFRα and PDGFRβ. The β-receptor binds only the PDGF-B chain with high affinity, while the αreceptor can bind either PDGF-A or -B chains. Both PDGF ligands and their receptors have been linked to such cellular responses as mitogenisis, cell migration, chemotaxis, adhesion and differentiation in a variety of cell types.

Several studies have reported fetal cardiac abnormalities associated with disruption of PDGF and its receptors. In spontaneous mutants lacking the PDGF α-receptor (Patchmice), fetal hearts are generally dilated and exhibit valve and outflow tract defects. Similar defects are observed in normal embryos injected with antibodies to block the functioning of the PDGF-A chain. Disruption of PDGF-B function results in ventricular and atrial dilation, reduction of the ventricular wall, and hyper-trabeculation.

Platelets play a major role in hemostasis due to their ability to adhere and aggregate at sites of vessel wall injury. Damage to the inner surface of arteries includes ruptures or tears at the site of atherosclerotic plaques or injury resulting from interventional procedures. Uncontrolled platelet recruitment and aggregation at these sites can lead to complete occlusion of the vessel. Thus the understanding of platelet function and structure has become an important goal in preventing vascular disease. We employed cryo-HRSEM techniques to gain more insight into the surface morphology of both quiescent and thrombin stimulated platelets.

Platelet rich plasma (PRP) was obtained by mixing whole blood (21 ml) drawn from juvenile pigs with 3 ml of acid citrate dextrose and centrifugation at 300g for 10 min. To obtain washed platelets the PRP was washed three times with a citrate wash buffer consisting of 36mM citric acid, 5mM glucose, 5mM KCl, 2 mM CaCl2, 1 mM MgCl2, 90 mM NaCl, pH 6.5.

Spaceflight induced mitochondrial alterations have been reported for muscle and may be associated with altered physiological functions in space. Mitochondrial alterations are also indicative of preapoptotic events which are seen in greater amounts in cells exposed to spaceflight when compared with cells cultured at 1 g. Preapoptotic mitochondrial changes include alterations of processes at the inner mitochondrial membrane and can result in changes in mitochondrial volume. Higher amounts of oxidative stress during space flight may be one of the causes for changes which lead to apoptosis. Jurkat cells flown on the STS-76 space shuttle mission showed an increase in the number of cells with apoptotic bodies early in the mission and a time-dependent, microgravity-related increase in the Fas/APO-1 cell death factor. Here we investigated the morphology of mitochondria in Jurkat cells exposed to spaceflight during the STS-76 mission.

Fibrinogen is composed of three pairs of polypeptide chains, termed Aα, Bβ and γ, respectively. Proteolytic conversion of fibrinogen to fibrin by thrombin releases fibrinopeptide A and exposes an N-terminal polymerization site ('EA’) in the central E domain of the molecule. This site interacts with a constitutive complementary site in each outer D domain ('Da’) to drive the molecular assembly process by end-to-middle domain non-covalent ‘Da:EA’ interactions. End-to-end aligned double-stranded fibrils are formed in coordination with another recently described constitutive self-association site (termed ‘D:D’)fhat is situated at the outer end of each D domain. The D:D site contributes to end-to-end molecular alignment of fibrin molecules within each fibril strand. Concomitant branching and lateral fibril associations to form thick fibers, lead to formation of the mature fibrin clot.

Fibrinogen Marburg is a homozygous hypodysfibrinogenemia lacking amino acid residues Aα461- 610 due to a stop codon at position 461 of the Aα chain.

Leukocytes adherence receptors are the basis of cells interactions1. Flow cytometry (FCM) makes it possible to assess a characterization of the activation level of a given cellular population by receptor quantifying2. That technique, however does not integrate at the same time, all others factors of leucocyte adhesive phenotype regulation, as spatial distribution and molecular conformation. Our study consisted in exploring the main adhesion receptors (CD62L, CDllb/CD18) on the surface of Polymorphonuclear Neutrophils (PMN) that were prepared under identical conditions and simultaneously analyzed by FCM and Conventional Optical Scanning Microscopy/Deconvolution3 (COSM). Methods: PMN cells from whole blood were obtained using Polymorphprep™. Isolated PMN (105 cells /ml) were incubated with Tumor Necrosis Factor (TNFα, 100 UI/ml) at 37°C for one hour. Quantification of cell surface molecules was assessed according to the quantitative indirect immunofluorescence3 method using QIFIKIT® (Dako, France).

Tissue Factor Pathway Inhibitor (TFPI) is a potent inhibitor of the extrinsic coagulation system, synthesized in endothelial cells. Membrane bound TFPI has recently been shown to play an important role in the degradation of activated coagulation factors in the endothelium. Comparison of subcellular TFPI localization patterns and TFPI production between Human Umbilical Vein Endothelial Cells (HUVEC) and an immortalized cell line (ECV 304) are presented here, as are the essential protocol modifications that we used to obtain labeling results by both light- and electron microscopy. We show that ECV 304 cells are similar to HUVEC in that TFPI is present in the Golgi complex (fig. 1) as well as in the endocytic pathway of ECV cells. Additionally, they secrete higher levels of TFPI into the culture medium than HUVEC. A colocalization of anti-TFPI with endocytosed BSA-gold, as well as with accumulated DAMP, demonstrated the presence of TFPI in the endocytic pathway.

A debated and yet unanswered question, in regard to polarization and directed movement of phagocytic cells, concerns the distribution of chemoattractant receptors during cell locomotion1. We have therefore studied the instantaneous distribution of N-formyl-peptide receptors on living neutrophils. Using a fluorescent N-formyl-peptide receptor antagonist, tert-butyloxycarbonyl-Phe(D)-Leu-Phe(D)-Leu-Phe-OH (Boc-FLFLF), and a fluorescent receptor agonist, formyl-Nle-Leu-Phe-Nle-Tyr-Lys (fnLLFnLYK), the localization of the chemoattractant receptors could be followed during random migratio2. Neutrophils were adhered to plasma-coated coverslips. A Nomarski differential interference contrast (DIC)- image was taken, and rapidly followed by a fluorescence-image captured with a water-cooled, slow-scan CCD-camera. Then a second DIC-image was directly recorded to reveal the direction of cell movement.

Using fnLLFnLYK we observed that the distribution of N-formyl-peptide receptors was clearly heterogeneous as shown in figure. Fluorescence was concentrated mainly at the rear and front of elongated locomoting cells, leaving the cell body almost non-fluorescent.

Using microbes for the biological control of pests is progressing very rapidly. Because of the high specificity and none of toxicity to the vertebrates, they become the environmental biopesticides. The most commonly used entomopathogen is Bacillus bacteria, such as B. thuringiensis.Mass culturing of B. thuringiensisin different types of fermentor is experimenting in order to reach the highest yield of endospore and the crystalline endotoxin, the main virulent components for the pesticidal activity.

Bacillus thuringiensisproduces endospore and the parasporal inclusions, Hannay (1953) observed in bacterium B. thuringiensis a mature endospore and a prism-shaped crystal (parasporal crystal).’ The endospore and the endotoxin crystal vary during growth depending upon the availability of nutrient. Glucose concentration in medium has enormous effects on the production of parasporal crystal, B. thuringiensiscan not grow, nor produce parasporal crystal in low concentration of glucose medium. The formation time of the endotoxin crystal also differs in different subspecies.

The protozoan parasite Toxoplasma gondiiis an obligate intracellular parasite that exhibits gliding and twisting motility during cell locomotion and host cell invasion. By using molecular and genetic approaches it has been determined that actin and myosin are localized beneath the parasite plasma membrane and produce the force for motility and active penetration during host cell invasion. However, structural evidence for actin fibers beneath the plasma membrane is still missing. Recently Chavez et al. demonstrated actin-like filaments in isolated cytoskeletal complexes. Our aproach has been to remove the cell membrane with 0.15% Triton X-100 in cytoskeleton preserving buffer, followed by imaging with low voltage field emission SEM. As seen in Fig. I, we could demonstrate the subpellicle actin network in parasites invading a host cell (arrow). Fig. 2 shows a similar subsurface network of actin filaments in a parasite gliding on glass.

The geminiviruses are a group of plant DNA viruses characterized by having one or two copies of a single-stranded, circular DNA genome and frequent occurrence of geminate, quasi-isometric particles as observed by transmission electron microscopy. The Geminiviridaefamily is classified into three genera (Mastrevirus, Curtovirus and Begomovirus)based on the number of DNA components, the plant hosts, and the transmission vectors. Maize streak virus (MSV), the type member of the Mastrivirusgenus, is transmitted by the leafhopper and infects Gramineaespecies. Wheat dwarf virus, Digitaria streak virus, and Chloris striate mosaic virus (CSMV) are examples of other members of the Mastrivirusgenus. The Nigerian strain of MSV (MSV-N) contains one copy of a singlestranded, circular DNA molecule (2687 nucleotides). Two protein products, VI and V2, are coded by the MSV-N genome.2 V2 (244 amino acids) is the only coat protein found in virions.

Chilo iridescent virus (CIV), the type species of the genus Iridovirusin the family Iridoviridae,was first isolated from the rice stem borer, Chilo suppressalis,a member of Lepidoptera insect order. ‘2 CIV is being considered as a potential pest control agent because of its wide host range which includes leafhoppers and some arthropods. The virion (∼lxl09 daltons) encapsidates a 209 kbp, dsDNA genome within its fiber-covered, icosahedral shell. The virion is composed of about 26 structural proteins, two (P50 and P'50, 50kDa each) of which are the major capsid proteins. P50 migrates as a monomer in either a reducing or non-reducing SDS-PAGE gel and is exposed to the surface, whereas P'50 exists as a disulfide-bond, stabilized trimer in a non-reducing gel and is only partially exposed. Virions contain 9% lipid present as a lipid bilayer within the protein capsid.

Lyme disease is the most common arthropod-borne infection in the United States. Over 100,000 cases have been reported to date. The disease is a multisystem disorder with dermatologic, neurologic and rheumatologic manifestations. The causative agent, Borrelia burgdorferi1has been isolated from ticks, animals and humans from around the world and can generally be cultured in the laboratory using BSK-II medium.

While biologically significant concentrations of eukaryotic cell inhibitors such as aphidicolin, ara C, cis platinum, CPX, hydroxyurea, mimosine, nalidixic acid, trioxsalen and boromethyglycine showed little effect on the growth of Borrelia burgdorferiwhen added to BSK-II cultures, PPMP, a spingolipid analogue, showed immediate and profound inhibitory effects when monitored by dark-field microscopy, transmission electron microscopy (TEM), field emission scanning electron microscopy (SEM) and by optical density measurements at 600 mμ. PPMP (dl-thzreo-l-phenyl-2-palmitoylamino-3-morpholino-l-propanol) is known to inhibit the synthesis of spingomyelin in Chinese hamster ovary cells and to inhibit the synthesis of glucosylceramides in a large variety of mammalian cells.

Clofoctol [2-(2,4-dichlorobenzyl)-4-(tetramethyl-l,l,3,3-butyl) phenol] is a synthetic antibacterial compound with activity against both Gram-positive1 and Gram-negative2 microorganisms. Although the specific mechanism of Clofoctol action has not been fully elucidated, it is reported to alter the permeability of the cytoplasmic membrane in Bacillus subtilis, and is used clinically to treat upper respiratory tract infections in humans. Staphylococcus aureus is a major human Grampositive pathogen that causes a variety of human diseases ranging from localized skin suppuration and food poisoning to life threatening presentations such as septicemia and endocarditis. Several clinical isolates of S. aureus have recently been identified that are resistant to all currently available antibacterial therapies. Consequently, the identification of new antimicrobial targets in this organism is of paramount importance. The purpose of this study was to investigate the in vitro effects of Clofoctol on S. aureus.

Ultrastructural examination of S. aureus revealed a population of actively dividing cells.

Ticks harbor several different genera of endosymbiotic bacteria. These obligate intracellular bacteria, most of which appear to be nonpathogenic for the tick, persist in nature by being transmitted transovarially from generation to generation. Those in the genus Rickettsiabelong to the spotted fever group (SFG) of rickettsia which includes both mammalian pathogenic and nonpathogenic species. The species that cause spotted fevers in humans, e.g. Rickettsia rickettsii, are well characterized but those not known to cause disease remain poorly understood. Transmission electron microscopy on SFG rickettsia cultured in tick cell cultures offers a powerful way to examine dynamic host parasite interactions in these apparently nonpathogenic SFG species.

We have successfully isolated two unknown, nonpathogenic rickettsia strains in tick cell lines. T2 was isolated from an Ixodes ricinus tick collected in the English Garden in Munich, Germany and is propagated in an Ixodes scapularis cell line, ISE6.

A current review (1) lists 21 cyanophages of coccoid and filamentous heterocystic and non-heterocystic blue-green algae (BGA). The capsid diameters of these viruses range from 50-90 nm, and none have been previously reported for Microcoleus,a sheath-producing, filamentous, surface colonizing BGA (Fig. 1), of the order Oscillatoriales, and class Cyanophyceae (= Cyanobacteria). From a freshwater culture of Microcoleussp. we report here a putative cyanophage with a side-to-side hexagonal capsid diameter of 140 nm, based on measurements from thin sections of algal filaments prepared for transmission electron microscopy (TEM).

An earlier report (2) documented the ultrastructure of mucilage secretion, and its role in sheath, trichome and filament formation in an isolate of the BGA Microcoleus sp. grown in soil-water medium. Now we report large cyanophage-like particles in a majority of cells making up the trichomes. These putative hexagonal viral capsids (Figs. 2-5) are mainly clustered in the center or to one side of the nucleoplasm.

Whipple's disease is a rare systemic disorder with the intestinal tract being the major site of predilection. The characteristic histologic features are the infiltration of large numbers of macrophages, which have a clear or vacuolated cytoplasm. In his original documentation of “a hitherto underscribed disease”, Whipple interpreted the vacuo lation to be due to deposits of fat and fatty acids and gave the name “interstinal lipodystrophy” to the pathology. In this report, Whipple did describe the presence of rod shaped organisms in Levaditi (reduced silver) stained preparations, but, it was not until a half century later, that the definitive presence of intracellular organisms was demonstrated by means of transmission electron microscopy. Further investigations showed that the organism is a Gram positive actinomycete, which has been designated as Tropheryma whippelii.

We report the case of a 72 year old woman, who was admitted with the chief complaints of abdominal cramps and diarrhea.

During April-July 1998, an increase in fatal cases of neurologic disease in young children occurred in Taiwan, with at least 55 fatalities reported. Concurrently, an outbreak of hand, foot, and mouth disease (HFMD) was also occurring. In fatal cases, the acute illness was characterized by fever, or rash, or mouth ulcers, followed by a rapid cardiopulmonary failure; death frequently occurred within 24 hours of hospitalization. Approximately three-fourths of the fatalities were in children less than 3 years of age. We report here the findings from autopsy specimens from two of the fatal cases of encephalomyelitis.

In Case 1, a 9-year-old female, H&E sections of central neurologic system (CNS) tissue showed perivascular infiltrate, areas of inflammation, necrosis, and neuronal degeneration. Immunohistochemical (IHC) staining was positive when using a monoclonal antibody for enterovirus 71 (EV71), a picornavirus associated with HFMD.

Acute lung injury is defined as a syndrome of inflammation resulting in increased capillary-alveolar permeability that is associated with a constellation of clinical, radiological and physiological abnormalities. Adult respiratory distress syndrome (ARDS), relatively common in the intensive care, is a more specific, severe form of ALI, with diverse causes. Diffuse alveolar damage is the pathognomonic feature of the syndrome. Under the pathophysiologic conditions of increasing capillary membrane permeability, large macromolecules can gain access to the interstitium, resulting in pulmonary interstitial edema, and from there enter the alveolar space in severe cases. Detecting the distribution of macromolecules in lung tissue, therefore, constitutes evidence of the injury. Traditional pathologic examination of biopsy/autopsy materials is the only route to provide pathologic evidence of the capillary-alveolar membrane damage induced lung injury. Although morphometric analyses are more laborious, they provide qualitative assessment of morphological changes that is an important aspect of acute lung injury, see Fig.l.