Ergastoplasmic paracrystalline inclusion bodies in the adipose gonadal envelope and fat body of the glow worm, Lampyris noctiluca (Insecta, Coleoptera).

Abstract The gonads of glow worm larvae are enveloped by adipose tissue which represents a specialized fat body. The adipose gonadal envelope, and also to a lesser extent the fat body cells, contain tubular paracrystalline inclusion bodies (PIBs). Cells of other tissues are devoid of such inclusions. The PIBs form in the cisternae of rough ER. In young larvae PIB formation is sparse, but at advanced larval stages PIBs often occur as bundles in stacks of ergastoplasm. Typically, a PIB within a cisterna consists of four to seven parallel tubules. The outer diameter of a tubule is ca 28.8 nm and the width of the tubule lumen ca 12.2 nm. The “wall” of a tubule contains globular protein subunits…

The ultrastructure of multinucleate giant cells

Abstract A survey of the available ultrastructural data on physiologically and pathologically occurring and virally-induced multinucleate giant cells (MNGCs) is presented. Emphasis is initially placed upon the bone osteoclast, the skeletal muscle myotube and the placental syncytiotrophoblast. The widespread occurence of MNGCs in a range of pathological situations is discussed, with emphasis upon the broad involvement of the macrophage in inflammatory responses. Many viruses produce cell fusion in vivo and in vitro when cell cultures are infected. Several examples are given. A clear distinction is drawn between viral fusion from “without” and viral fusion from “within” the cell. The cytopath…

In vitro fibrillogenesis of the amyloid beta 1-42 peptide: cholesterol potentiation and aspirin inhibition.

Understanding the formation of extracellular amyloid neurofibrillar bundles/senile plaques and their role in the development of Alzheimer's disease is of considerable interest to neuroscientists and clinicians. Major components of the extracellular neurofibrillar bundles are polymerized amyloid beta (Abeta) peptides (1-40), (1-42) and (1-43), derived in vivo from the soluble amyloid precursor protein (sAPP) by proteolytic (beta- and gamma-secretase) cleavage. The Abeta(1-42) peptide is widely considered to be of greatest significance in relation to the pathogenesis of Alzheimer's disease. A well-defined ultrastructural characteristic within Alzheimer dense plaques is the presence of helical…

Transmission electron microscopical studies on some haemolymph proteins from the marine polychaete Nereis virens.

Abstract The hexagonal bilayer haemoglobin molecule from Nereis virens has been investigated in a comparative study using several different negative stain electron microscopical specimen preparations (i.e. by conventional adsorption to continuous carbon support films, by the negative staining-carbon film technique and by negative staining across the holes of holey carbon support films with air-drying and rapid freezing/cryo-negative staining). The benefits and limitations of these different approaches are indicated, with the overall conclusion that negative staining with ammonium molybdate across holes creates the best possibilities for molecular imaging, and also has the potential for the …

Keyhole limpet hemocyanin (KLH): a biomedical review

In this review we present a broad survey of fundamental scientific and medically applied studies on keyhole limpet hemocyanin (KLH). Commencing with the biochemistry of KLH, information on the biosynthesis and biological role of this copper-containing respiratory protein in the marine gastropod Megathura crenulata is provided. The established methods for the purification of the two isoforms of KLH (KLH1 and KLH2) are then covered, followed by detailed accounts of the molecular mass determination, functional unit (FU) structure, carbohydrate content, immunological analysis and recent aspects of the molecular genetics of KLH. The transmission electron microscope (TEM) has contributed signific…

Inflammatory and Infectious Basis of Atherosclerosis

Haliotis tuberculata hemocyanin (HtH): analysis of oligomeric stability of HtH1 and HtH2, and comparison with keyhole limpet hemocyanin KLH1 and KLH2

The multimeric/higher oligomeric states of the two isoforms of Haliotis tuberculata hemocyanin (HtH1 and HtH2) have been assessed by transmission electron microscopy (TEM) of negatively stained specimens, for comparison with previously published structural data from keyhole limpet hemocyanin (KLH1 and KLH2) [see Harris, J.R., Gebauer, W., Guderian, F.U., Markl, J., 1997a. Keyhole limpet hemocyanin (KLH), I: Reassociation from Immucothel followed by separation of KLH1 and KLH2. Micron, 28, 31-41; Harris, J.R., Gebauer, W., Söhngen, S.M., Nermut, M.V., Markl, J., 1997b. Keyhole limpet hemocyanin (KLH). II: Characteristic reassociation properties of purified KLH1 and KLH2. Micron, 28, 43-56; H…

The structure of gas-filled n-butyl-2-cyanoacrylate (BCA) polymer particles

Abstract The structure of gas-filled poly-[n-butyl-2-cyanoacrylate] (BCA) particles has been demonstrated by negative staining with uranyl acetate, platinum-carbon shadowing of air-dried material and thin sectioning of the aqueous suspension of BCA particles, embedded in water-soluble melamine resin. The polymer shell of the hollow particles possesses a globular outer surface and a smoother inner surface.

Application of the negative staining technique to both aqueous and organic solvent solutions of polymer particles

Abstract Transmission electron microscopy (TEM) imaging of several different polymers in aqueous and organic solutions using the negative staining technique is demonstrated, to emphasise the possibilities of this specimen preparation technique for polymer science. Negative stains can readily be prepared in both water and organic solvents (e.g. dimethyl formamide (DMF), dimethyl sulfoxide (DMSO) and tetrahydrofurane (THF)). Polymer particle size, size distribution and shape seen in negative stain correlates well with those of unstained materials. The particle surface and smaller particles (e.g. 10–20 nm) are more clearly defined in the presence of a negative stain. The inherent problems of s…