Electron Microscope Research Papers - Academia.edu (original) (raw)

The case of a 33-year-old woman with primary carcinoid of the uterine cervix is reported. Primary carcinoid tumor is well known to occur in organs such as the gastrointestinal tract, lung and gonads. However, its occurrence in the uterine cervix is rare. To our knowledge, primary carcinoid of the uterine cervix has not been reported from the United States, although it has been well documented by non-American authors. Light microscopically, the tumor was characterized by formation of solid nests, trabeculae and glands. The cells therein showed argyrophil granules but were negative for argentaffin reaction. Electron microscopy revealed the presence of numerous neurosecretory granules and microfilaments. On the basis of light microscopic ultrastructural and cytochemical properties, the tumor is believed to arise from the normal argyrophil cell of the cervix and is regarded as an endocrine tumor, a member of the group of neoplasms called apudomas. Cancer 43:535-538, 1979. ARCINOID OF THE UTERINE CERVIX became C a convincingly established a n d accepted entity only in the recent past. It was first described by Albores-Saavedra' in 1972. Thereafter, Tateishi et U L .~~ published their observations of 5 such cases a n d coined the term "argyrophil cell carcinoma" for the specific type of cervical carcinoma derived from the argyrophil cells, normally found in the cervical epithelium. More recently, Albores-Saavedra' reported additional observations o n 12 cases of carcinoid tumors of the uterine cervix. Since then, occasional case reports have been cited in literature by European (English6 and Czech-o~lovakian'~) authors. An apparent lack of familiarity and adequate documentation in the American literature prompts this report.

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- Cancer, Case Report, Electron Microscope

The scarcity of sizeable specimens of normal oral mucosa for experimental purposes has hampered research on oral epithelium. Because large specimens of viable human vaginal mucosa are readily available and because vaginal and buccal epithelia are microscopically similar, vaginal mucosa has been used successfully to establish a human cyst model in experimental animals. The ultrastructure and distribution of keratin filaments in these epithelia are also similar, as is their permeability to water and a number of chemical substances. Therefore, if vaginal mucosa could be substituted for buccal mucosa it would expedite research on the epithelium of buccal mucosa. To strengthen further the concept that vaginal epithelium could replace buccal epithelium in certain experimental studies, the thickness of these epithelia, their patterns of surface keratinization, the presence or absence of intercellular lipid lamellae and their lipid contents were now compared. Thirty-three specimens of vaginal mucosa from postmenopausal women and 36 of buccal mucosa were investigated. To compare the thickness of the epithelial layers the number of cell layers in sections of 20 vaginal and 20 buccal mucosal specimens were counted in the three thickest and three thinnest regions of each specimen. Surface keratinization was evaluated on sections stained with the Picro-Mallory method. To demonstrate lipid lamellae two vaginal and two buccal mucosa specimens were examined electron microscopically after normal fixation and postfixation in ruthenium tetroxide. Following solvent extraction of 11 vaginal and 14 buccal epithelia, quantitative lipid analyses were performed using thin-layer chromatography. No statistically significant differences were found between the maximum and minimum number of epithelial cell layers. The patterns of surface keratinization and the distribution and appearance of the lipid lamellae in the intercellular spaces were similar. The lipid composition of the two epithelia corresponded, except for the cholesterol esters and glycosylceramides, which were higher in buccal epithelium. Ceramides for vaginal epithelium and triglycerides for buccal epithelium were not determined. Based on structural similarities, a similar lipid composition and earlier findings, it is concluded that vaginal epithelium can be used as a substitute for buccal epithelium in certain in vitro, and possibly for in vivo, studies.

- by Armorel van Eyk
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- Zoology, Dentistry, Biomedical Engineering, Electron Microscopy

Surface-coated cardiopulmonary bypass (CPB) has been shown to have excellent biocompatibility during cardiac surgery in adults, but there have been only a few reports demonstrating the efficacy of this coating for congenital cardiac surgery. We tested the efficacy of poly-2-methoxyethylacrylate (PMEA) coating for CPB circuits in congenital cardiac surgery. Eleven operative cases of ventricular septal defect were studied: group C (control: no coating, n = 5) and group P (PMEA coating, n = 6). The platelet count and beta-thromboglobulin (beta TG), fibrinogen (FBG), thrombin-antithrombin complex (TAT), and neutrophil elastase levels were measured during the operation. Postoperative chest tube drainage was analyzed and the surface of the artificial lung was observed with an electron microscope. Elevation of TAT and neutrophil elastase was suppressed in group P (P < 0.05). Observation of the artificial lung surface using an electron microscope clearly revealed fewer blood cells were a...

- by Ikuo Fukuda
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- Cell Adhesion, Scanning Electron Microscopy, Artificial Organs, Polymers

Aims/hypothesis Defects in pancreatic beta cell turnover are implicated in the pathogenesis of type 2 diabetes by genetic markers for diabetes. Decreased beta cell neogenesis could contribute to diabetes. The longevity and turnover of human beta cells is unknown; in rodents <1 year old, a half-life of 30 days is estimated. Intracellular lipofuscin body (LB) accumulation is a hallmark of ageing in neurons. To estimate the lifespan of human beta cells, we measured beta cell LB accumulation in individuals aged 1-81 years.

- by Barbara Hansen
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- Electron Microscopy, Aging, Mathematical Modelling, Cell Division

Immunoblot analyses performed with three monoclonal antibodies (MAbs) that recognized the nitrite oxidoreductase (NOR) of the genus Nitrobacter were used for taxonomic investigations of nitrite oxidizers. We found that these MAbs were able to detect the nitrite-oxidizing systems (NOS) of the genera Nitrospira, Nitrococcus, and Nitrospina. The MAb designated Hyb 153-2, which recognized the alpha subunit of the NOR (alpha-NOR), was specific for species belonging to the genus Nitrobacter. In contrast, Hyb 153-3, which recognized the beta-NOR, reacted with nitrite oxidizers of the four genera. Hyb 153-1, which also recognized the beta-NOR, bound to members of the genera Nitrobacter and Nitrococcus. The molecular masses of the beta-NOR of the genus Nitrobacter and the beta subunit of the NOS (beta-NOS) of the genus Nitrococcus were identical (65 kDa). In contrast, the molecular masses of the beta-NOS of the genera Nitrospina and Nitrospira were different (48 and 46 kDa). When the genus-s...

- by Eva Spieck
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- Electron Microscopy, Activated Sludge, Nitrogen Cycle, Multidisciplinary
- by Pierre Bordet
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- Materials Engineering, Condensed Matter Physics, Materials Science, Chemistry

Several neurotransmitters and hormones with potential to trigger a simultaneous contraction of the oviducts and the spermathecal myoepithelium were examined. Saline (0.05 ml), or 0.05 ml saline plus acetylcholine (9ms), norepinephrine (50 gg), arginine-vasotocin (25 units), prostaglandin F2~(3 gg) were injected into the spermathecal region of female newts (n = 24 per group). The numbers of sperm present in the cloacae of prostaglandin-injected animals (107 • 30 SEM) were significantly greater than the numbers detected in saline (27 4-5 SEM) and in uninjected (14 4-3 SEM) controls. Smaller and less consistent increases in the numbers of sperm were detected in the vasotocin-and norepinephrine-injected groups. Study of sections from ovulating female newts failed to produce evidence that pressure from the passage of ova through the posterior portion of the oviduct forced sperm from the spermatheca. Observations indicate an active role for the spermathecal myoepithelium in the discharge of stored sperm and of a role for prostaglandin F2~ in triggering that discharge. Key words. Spermatheca; newt spermatheca; sperm storage; sperm discharge from storage; hormonal action in sperm discharge; prostaglandin and sperm discharge.

Sponges of the Aplysinidae family contain large amounts of bacteria that are embedded within the sponge tissue matrix. In order to determine the stability and specificity of the Aplysina^microbe association, sponges were maintained in recirculating seawater aquariums for 11 days. One aquarium was left untreated, a second one contained 0.45 Wm filtered seawater (starvation conditions) and the third one contained 0.45 Wm filtered seawater plus antibiotics (antibiotics exposure). Changes in the microbial community were monitored using group-specific, 16S rRNA targeted oligonucleotide probes, by denaturing gradient gel electrophoresis and by electron microscopic observations. Furthermore, the changes in the natural product profile were monitored using high-performance liquid chromatography. The measured parameters showed that a large fraction of the sponge-associated microbial community could not be cleared under the given experimental conditions. Based on these cumulative results we postulate that a large fraction of sponge-associated bacteria resides permanently in the Aplysina aerophoba mesohyl pointing to a highly integrated interaction between the host sponge and associated microorganisms. ß

A new high-resolution recording device for transmission electron microscopy (TEM) is urgently needed. Neither film nor CCD cameras are systems that allow for efficient 3-D high-resolution particle reconstruction. We tested an active pixel sensor (APS) array as a replacement device at 200, 300, and 400 keV using a JEOL JEM-2000 FX II and a JEM-4000 EX electron microscope. For this experiment, we used an APS prototype with an area of 64 Â 64 pixels of 20 mm Â 20 mm pixel pitch. Single-electron events were measured by using very low beam intensity. The histogram of the incident electron energy deposited in the sensor shows a Landau distribution at low energies, as well as unexpected events at higher absorbed energies. After careful study, we concluded that backscattering in the silicon substrate and reentering the sensitive epitaxial layer a second time with much lower speed caused the unexpected events. Exhaustive simulation experiments confirmed the existence of these back-scattered electrons. For the APS to be usable, the backscattered electron events must be eliminated, perhaps by thinning the substrate to less than 30 mm. By using experimental data taken with an APS chip with a standard silicon substrate (300 mm) and adjusting the results to take into account the effect of a thinned silicon substrate (30 mm), we found an estimate of the signal-to-noise ratio for a back-thinned detector in the energy range of 200-400 keV was about 10:1 and an estimate for the spatial resolution was about 10 mm. r

- by Mark Ellisman
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- Electron Microscopy, Silicon, Transmission Electron Microscopy, Low Energy Buildngs

Insects and crustaceans offer excellent model systems to study vitellogenesis in invertebrates. This paper gives a comprehensive account of the receptor-mediated yolk protein uptake in a lepidopteran insect Spodoptera litura and a decapod crustacean Scylla serrata . The vitellogenin (Vg) of both these arthropods has been characterized using electrophoretic and immuno-blotting techniques. The Vg's of both the animals are glycolipoproteins and exhibit immunological identity with their respective lipovitellins (Lv's). The physico-chemical characterization of vitellogenin receptors (VgR) of these arthropods revealed several similarities in their molecular weight and binding affinity with vitellins, which was increased considerably by divalent cation calcium. On the other hand, their binding affinity decreased significantly when treated with polyanionic suramin. These properties, along with the strong affinity of crab VgR for mammalian LDL and VLDL, qualify them as members of LDL...

- by Chinnapandi Bharathiraja
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- Biology, Comparative Study, Model System, Molecular weight

To gain a better understanding of the factors involved in textural changes in Mozzarella cheese during storage, electron microscopic imaging was used to compare the ultrastructure of the protein matrix on the day of stretching (0 weeks) and after 6 weeks of storage at 4°C. Low-fat and full-fat cheeses were prepared from nonhomogenized milk and from milk homogenized at 10.3 and 17.2 MPa. Analysis of the stained electron density distribution in image transforms of the protein matrix revealed that spacing patterns of regular structures with the dimensions of casein submicelles changed during storage, in most cases forming larger aggregates at longer average spacings, but there were no significant changes in total electron density between fresh and stored cheeses. These effects were related to proteolysis. Submicelles in low-fat cheeses homogenized at 17.2 MPa reorganized differently, a likely result of decreased proteolysis. Submicelles formed part of a new membrane around fat globules in cheeses made from homogenized milk, as previously observed. Changes in submicelle size and distribution could explain some of the differences in texture properties between fresh and stored Mozzarella cheeses, and between products made from homogenized and nonhomogenized milk.

- by Peter Cooke
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- Dairy, Electron Density, Clinical Sciences, Food Sciences

The contractile proteins actin and myosin are of considerable biological interest. They are essential for muscle contraction and in eukaryotic cells they play a crucial role in most contractile phenomena. Over the years since the first fluorescence resonance energy transfer (FRET) paper appeared, an extensive body of literature has accumulated on this technique using actin, myosin and the actomyosin complex. These papers are reviewed with several aims in mind: (i) we assess the reliability and consistency of intra-and inter-molecular distances measured between the fluorescent probes attached to specific sites on these proteins; (ii) we determine whether the measurements can be assembled into an internally consistent model which can be fitted to the known dimensions of the actomyosin complex; (iii) several of the FRET distances are consistent with the available structural data from crystallographic and electron microscopic dimensions; (iv) the modelled FRET distances suggest that the assumed value of the orientation factor (k 2 = 2/3) is reasonable; (v) we conclude that the model has a predictive value, i.e. it suggests that a small number of the published dimensions may be incorrect and predicts the magnitude of a larger number of measurements which have not yet been reported; and finally (vi) we discuss the contribution of FRET determinations to the current debate on the molecular mechanism of contraction.

- by Julian Barden
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- Physiology, Fluorescent Dyes and Reagents, Molecular Mechanics, Structured data

The pineal of viscacha (Lagostomus maximus maximus) is formed by two main cellular populations of pinealocytes and interstitial cells. A connective capsule surrounds the gland sending numerous septa containing blood vessels and nerves. In the specimens collected during summer the pinealocyte displays a defined contour and a clear cytoplasm with abundant ribosomes and numerous cisternae of endoplasmic reticulum. The pinealocytes observed during winter have cytological characteristics of active cells with dense and elongated mitocondria, dense bodies, and a developed Golgi complex. These seasonal glandular changes could be related to the environmental condition and mainly to the summer photoperiod. The presence of abundant nerve terminals in the perivascular spaces suggests a neural control on the blood vessels.

- by Jorge Guzmán
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- Electron Microscopy, Rodentia, Biological Sciences, Light
- by Sant Chawla
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- Electron Microscopy, Cancer, Amputation, Aged

With the aim of contributing to a better understanding of the haemolytic function of the spleen, a morphologic and morphometric study of this organ fixed by arterial perfusion was performed in nine patients with hereditary spherocytosis (HS). three with autoimmune haemolytic anaemia (AHA) and six with Hodgkin's disease without splenic involvement (controls). The spleen weight in HS and AHA (6 2 1 1 4 2 9 g. mean 1 SD) was significantly increased with respect to controls (I 68 f 36 g) (P = 0.003 1. In HS the red cell retention in the cords of Billroth was significantly increased (203 1 6 8 per I O4 pmL) with respect to the cases with AHA (9 3 1 3 5 per 10* pmZ) and to the controls (5 7 1 2 8 per lo4 pmL) (P=0,004). In HS and AHA the number of macrophages per The role of the spleen in haemolytic anaemia has been extensively studied (

- by E. Feliu
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- Scanning Electron Microscopy, Transmission Electron Microscopy, Macrophages, Adolescent
- by Edward Kenik
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- Crystal structure, Dislocations, Microstructures, Ion Beam

Barley endosperm begins development as a syncytium where numerous nuclei line the perimeter of a large vacuolated central cell. Between 3 and 6 days after pollination (DAP) the multinucleate syncytium is cellularized by the centripetal synthesis of cell walls at the interfaces of nuclear cytoplasmic domains between individual nuclei. Here we report the temporal and spatial appearance of key polysaccharides in the cell walls of early developing endosperm of barley, prior to aleurone differentiation. Flowering spikes of barley plants grown under controlled glasshouse conditions were hand-pollinated and the developing grains collected from 3 to 8 DAP. Barley endosperm development was followed at the light and electron microscope levels with monoclonal antibodies specific for (1 fi 3)-b-Dglucan (callose), (1 fi 3,1 fi 4)-b-D-glucan, hetero-(1 fi 4)-b-D-mannans, arabino-(1 fi 4)-b-D-xylans, arabinogalactan-proteins (AGPs) and with the enzyme, cellobiohydrolase II, to detect (1 fi 4)-b-D-glucan (cellulose). Callose and cellulose were present in the first formed cell walls between 3 and 4 DAP. However, the presence of callose in the endosperm walls was transient and at 6 DAP was only detected in collars surrounding plasmodesmata. (1 fi 3,1 fi 4)-b-D-Glucan was not deposited in the developing cell walls until approxi-mately 5 DAP and hetero-(1 fi 4)-b-D-mannans followed at 6 DAP. Deposition of AGPs and arabinoxylan in the wall began at 7 and 8 DAP, respectively. For arabinoxylans, there is a possibility that they are deposited earlier in a highly substituted form that is inaccessible to the antibody. Arabinoxylan and heteromannan were also detected in Golgi and associated vesicles in the cytoplasm. In contrast, (1 fi 3,1 fi 4)-b-D-glucan was not detected in the cytoplasm in endosperm cells; similar results were obtained for coleoptile and suspension cultured cells. Keywords Arabino-(1 fi 4)-b-D-xylans AE Arabinogalactan-proteins AE Cellularization AE Cell wall polysaccharides AE Endosperm AE (1 fi 3)-b-D-Glucan AE (1 fi 4)-b-D-Glucan AE (1 fi 3,1 fi 4)-b-D-Glucan AE Hetero-(1 fi 4)-b-D-mannans AE Hordeum Abbreviations DAP: Days after pollination AE

- by Rachel Burton and +1
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- Plant Biology, Immunohistochemistry, Transmission Electron Microscopy, Polysaccharides

GT Herman optimized (on a sufficiently large data set so as to lead to statistically significant results) without outrageous demands on computational resources. In the rest of this section we discuss how the image reconstruction problem... more

- by Rodney Brooks
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- Computer Science, Physics, Computed Tomography, Positron Emission Tomography
- by anita hoffer
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- Andrology, Electron Microscopy, Structural Integrity, Perfusion

Forty randomly selected dogs, arranged into three groups according to age, were examined light and electron microscopically. Lafora-like inclusion bodies were found in all cases of aged dogs without neurological signs. They appeared as PAS positive, round bodies measuring up to 15μm in diameter. Typically they had central cores and radiating peripheral lines. Electronmicroscopically, the inclusions consisted of irregularly clustered, short branching filaments measuring about 80–120 Å in diameter or of electrondense homogeneous or granular central cores with filamentous peripheral areas and located both in the perikarya and neuronal processes. The inclusions were disseminated all over the brain and spinal cord. The thalamic nuclei, a circumscribed area dorsal to the aqueduct, and the molecular layer of the superior colliculus were the most severely affected. The frequency of the inclusions showed age-dependency; the inclusions were not found in dogs younger than 2 years, but were extensive in all dogs of more than 8 years of age. The occurrence of the inclusions may therefore represent an age-dependent phenomenon. The relationship between the present findings and Lafora's disease is discussed.

- by s suu
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- Electron Microscopy, Aging, Dogs, Brain

This article describes the ultrastructural events associated with the differentiation and liberation of the exogenous gemmae produced in branched acropetal chains along the margins of the leaves in the liverwort Odontoschisma denudatum. Formation of a dorsal protrusion from young leaf cells containing a large central nucleus, small vacuoles, starch-free chloroplasts, scattered cytoplasmic lipid droplets but no oil bodies, signals the onset of the formation of the initial cell of a gemmiferous filament. The protrusion enlarges and the nucleus migrates into its base, therein dividing with the equator of the spindle virtually filling the central isthmus between the leaf surface and the now swollen tip of the initial cell. Subsequent divisions of the initial cell produce a chain of cells in atropetal succession. Transversely orientated microtubules line the cortical cytoplasm along the lateral walls of the terminal cells of the gemmiferous filaments, but are absent from the tips, thus suggesting that these cells elongate by intercalary, rather than by tip, growth. During mitosis microtubules are closely associated with the envelopes of spindle-shaped prophase nuclei, radiate from ill-defined spindle poles surrounded by plastids at metaphase and anaphase and form a dense phragmoplast array during telophase. Pre-prophase bands are absent and it may be that the nuclear equator determines the plane of division in gemmiferous filaments. Chloroplast division, associated with extremely transient plastid-dividing rings, takes place during interphase. Lateral branches of the growing filaments arise from subapical cells by reiteration of the first division mechanism.Immediately following the proliferative divisions, which take place in cells measuring only 5-6 μm in diameter, oil bodies suddenly appear as flat pleomorphic cisternae associated with endoplasmic reticulum and occasional microtubules. Their contents are electron-transparent apart from scattered osmiophilic droplets. Throughout their ontogeny the oil bodies are closely associated with cytoplasmic lipid bodies but there is no evidence of fusion. The nascent oil bodies swell rapidly to their final diameter, become ovoid to spherical in outline and are eventually suspended by fine cytoplasmic bridges within the vacuoles. The latter rapidly increase in size together with an expansion of the cells themselves until these reach their final diameter and length. The final event in gemma maturation is an endogenous division with the formation of a new internal wall along a phragmosome. Separation of the bicellular gemmae proceeds basipetally and involves the appearance of an electron-transparent line along the middle lamella in the cross walls, which often develop convex thickenings, and severing of the plasmodesmata. After their liberation shallow scars are visible on the leaf surface under the SEM. Gemma maturation sees a marked increase in the electron-opacity of the walls and dense staining of these together with Golgi vesicles with the periodic acid/thiocarbohydrazide/silver proteinate test for non-cellulosic carbohydrates. This change in wall chemistry and ultrastructure may be related to the fact that the maturing gemmae become extremely water repellant and are probably dispersed either on the surface of water films or in the air.

- by Roberto Ligrone
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- Plant Biology, Ecology, Morphogenesis, Endoplasmic Reticulum

Active packaging Fourier transform infrared spectroscopy Functional group interaction Hot air drying Low-pressure superheated steam drying Natural antimicrobial agent Staphylococcus aureus Transmission electron microscopy Vacuum drying a... more

- by Keshavan Niranjan and +1
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- Chemical Engineering, Food, Transmission Electron Microscopy, Antimicrobial activity

A series of surface-modified clays containing nanophase (np) iron oxide/oxyhydroxides of extremely small particle sizes, with total iron contents as high as found in Mars soil, were prepared by iron deposition on the clay surface from ferrous chloride solution. Comprehensive studies of the iron mineralogy in these "Mars-soil analogs" were conducted using chemical extractions, solubility analyses, pH and redox, x ray and electron diffractometry, electron microscopic imaging, specific surface area and particle size determinations, differential thermal analyses, magnetic properties characterization, spectral reflectance, and Viking biology simulation experiments. The clay matrix and the procedure used for synthesis produced nanophase iron oxides containing a certain proportion of divalent iron, which slowly converts to more stable, fully oxidized iron minerals. The clay acted as an effective matrix, both chemically and sterically, preventing the major part of the synthesized iron oxides from ripening, i.e., growing and developing larger crystals. The precipitated iron oxides appear as isodiametric or slightly elongated particles in the size range 1-10 nm, having large specific surface area. The noncrystalline nature of the iron compounds precipitated on the surface of the clay was verified by their complete extractability in oxalate. Lepidocrocite (3,-FeOOH) was detected by selected area electron diffraction. It is formed from a double iron Fe(II)/Fe(III) hydroxy mineral such as "green rust," or ferrosic hydroxide. Magnetic measurements suggested that lepidocrocite converted to the more stable maghemite (3,-Fe203) by mild heat treatment and then to nanophase hematite (a-Fe203) by extensive heat treatment. After mild heating, the iron-enriched clay became slightly magnetic, to the extent that it adheres to a hand-held magnet, as was observed with Mars soil. The chemical reactivity of the iron-enriched clays strongly resembles, and offers a plausible mechanism for, the somewhat puzzling observations of the Viking biology experiments. Their unique chemical reactivities are attributed to the combined catalytic effects of the iron oxide/oxyhydroxide and silicate phase surfaces. The reflectance spectrum of the clay-iron preparations in the visible range is generally similar to the reflectance curves of bright regions on Mars. This strengthens the evidence for the predominance of nanophase iron oxides/oxyhydroxides in Mars soil. The mode of formation of these nanophase iron oxides on Mars is still unknown. It is puzzling that despite the long period of time since aqueous weathering took place on Mars, they have not developed from their transitory stage to well-crystallized end-members. The possibility is suggested that these phases represent a continuously on-going, extremely slow weathering process. 20,831 20,832 BANIN ET AL.: NANOPHASE IRON MINERALS IN MA•S SOIL detection systems during the 1988-1990 oppositions [Bell et al., 1990; Roush et al., 1993; Singer et al., 1990]. Yet the mineralogical nature of the soil is far from being understood, nor are its time of formation and weathering processes known.

- by David Blake
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- Mars, Electron Diffraction, Heat Treatment, Multidisciplinary

Building upon the similarities between inelastic electron scattering and X-ray absorption we show that dichroism can be observed in electron energy loss spectrometry (EELS) in the transmission electron microscope (TEM). Natural or magnetic linear dichroism can be studied in electron scattering experiment with definite wave vector transfer in the interaction.

Corpus callosum of Jimpy mouse brain was investigated with the electron microscope in 14, 21, 29 days old animals, and compared with that of normal littermates. Myelination was almost lacking in Jimpy; this absence seems to be due to an... more

- by O. Robain
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- Corpus Callosum, Clinical Sciences, Neurosciences, Electron Microscope

Wolbachia are symbiotic endobacteria that infect the majority of filarial nematodes, including Wuchereria bancrofti, Brugia malayi and Onchocerca volvulus. Recent studies have suggested that Wolbachia are necessary for the reproduction and survival of filarial nematodes and have highlighted the use of antibiotic therapy such as tetracycline/doxycycline as a novel method of treatment for infections caused by these organisms. Before such therapy is conceived and implemented on a large scale, it is necessary to assess the prevalence of the endosymbiont in W. bancrofti from different geographical locations. We present data from molecular and electron microscopic studies to provide evidence for Wolbachia symbiosis in W. bancrofti microfilariae collected from two districts (Bankura and Birbhum) of West Bengal, India.

- by SUDIPTA MAITRA
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- Geography, Symbiosis, Transmission Electron Microscopy, Adolescent

In this study, we characterized lead (Pb 2+ ) accumulation and storage by the aquatic fern Azolla filiculoides. Lead precipitates were detected in the vacuoles of mesophyll cells of Azolla plants cultured for 6 d in rich growth medium containing 20 mg l -1 Pb 2+ . Energy dispersive spectroscopy (EDS) analysis of the relative element content of leaves collected from these plants revealed a 100% increase in the levels of P, S, Na and Ca and a 40% decrease in Mg and Cl compared to the untreated plants. Both Azolla whole plants and isolated apoplasts were incubated for 6 d in 20 mg l -1 Pb 2+ . Lead content in the whole plant composed 0.37%, 2.3% and 1.8% of the dry weight after 2, 4 and 6 d of growth, respectively, while the isolated Azolla apoplast contained 0.125%, 1.22% and 1.4% Pb 2+ , respectively. Lead content in Azolla whole plant increase by 200%, 100% and 22% after 2, 4 and 6 d of growth, respectively, when compared to Azolla apoplast. Dark, electron dense deposits of lead were observed in light and transmission electron microscope in leaf cells treated with lead. All the observed lead deposits were localized in vacuoles while larger lead deposits were found in mature leaves than in young leaves. No lead deposits were found in cells of the cyanobiont Anabaena when the plants were exposed to similar conditions. Activity and content of V-H + -ATPase were studied in Azolla plants grown in the presence of 20, 40 and 80 mg l -1 of lead for a period of 4 d. Activity of V-H + -ATPase was increased by 190%, 210% and 220%, respectively, but the content of V-H + -ATPase was reduced by all lead concentrations.

- by Elisha Tel-Or
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- Water, Kinetics, Plant Biology, Plant Physiology

Özet: Çalışmada, 2 yaşlı, 6 adet sazanda (Cyprinus carpio L.) gözlenen deri lezyonları makroskobik, histopatolojik ve elektron mikroskobik olarak değerlendirildi. Deride, boz beyaz fokal odaklar halinde gözlenen lezyonlardan alınan doku örneklerinde, epidermal hiperplazi, vakuoler dejenerasyon ve intrasitoplazmik inklüzyon cisimciklerine rastlanırken, elektron mikroskobik incelenmesinde hücre içi virus partiküllerine rastlandı. Gözlenen makroskobik ve mikroskobik bulguların, çiçek hastalığına bağlı olarak şekillendiği sonucuna varıldı.

- by Hijran Yavuzcan
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- FISH PATHOLOGY, Inclusion Bodies, Degeneration, Cyprinus Carpio

The structure of neuronal mitochondria from chick and rat was examined using electron microscope tomography of chemically fixed tissue embedded in plastic and sliced in D500-nm-thick sections. Three-dimensional reconstructions of representative mitochondria were made from single-axis tilt series acquired with an intermediate voltage electron microscope (400 kV). The tilt increment was either 1°or 2°ranging from 260°to 160°. The mitochondrial ultrastructure was similar across species and neuronal regions. The outer and inner membranes were each D7 nm thick. The inner boundary membrane was found to lie close to the outer membrane, with a total thickness across both membranes of D22 nm. We discovered that the inner membrane invaginates to form cristae only through narrow, tubular openings, which we call crista junctions. Sometimes the cristae remain tubular throughout their length, but often multiple tubular cristae merge to form lamellar compartments. Punctate regions, D14 nm in diameter, were observed in which the inner and outer membranes appeared in contact (total thickness of both membranes D14 nm). These contact sites are known to a play a key role in the transport of proteins into the mitochondrion. It has been hypothesized that contact sites may be proximal to crista junctions to facilitate transport of proteins destined for the cristae. How-ever, our statistical analyses indicated that contact sites are randomly located with respect to these junctions. In addition, a close association was observed between endoplasmic reticulum membranes and the outer mitochondrial membrane, consistent with the reported mechanism of transport of certain lipids into the mitochondrion. r 1997 Academic Press

- by Christian Renken
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- Electron Microscopy, Structural Biology, Electron Tomography, Mitochondria

The surface (S-) layer of the hyperthermophilic archaebacterium 1 Max-Planck-Institut fü r Biochemie, Am Klopferspitz Staphylothermus marinus was isolated, dissected into separate domains by chemical and proteolytic methods, and analyzed by spectroscopic, electron 18a, D-82152 Martinsried microscopic and biochemical techniques. The S-layer is formed by a poorly Germany ordered meshwork of branched, filiform morphological subunits resembling 2 Maurice E. Mü ller Institut dandelion seed-heads. A morphological subunit (christened by us Biozentrum, Universität tetrabrachion) consists of a 70 nm long, almost perfectly straight stalk ending Basel, Klingelbergstr. 70 in four straight arms of 24 nm length that provide lateral connectivity by CH-4056 Basel, Switzerland end-to-end contacts. At 32 nm from the branching point, tetrabrachion carries two globular particles of 10 nm diameter that have both tryptic and 3 Lehrstuhl fü r Mikrobiologie chymotryptic protease activity. Tetrabrachion is built by a tetramer of M r der UniversitätsstraPe 92,000 polypeptides that form a parallel, four-stranded a-helical rod and D-93053 Regensburg separate at one end into four strands. These strands interact in a 1:1 Germany stoichiometry with polypeptides of M r 85,000 to form the arms. The arms are composed entirely of b-sheets. All S-layer components contain bound carbohydrates (glucose, mannose, and glucosamine) at a ratio of 38 g/100 g protein for the complete tetrabrachion-protease complex. The unique structure of tetrabrachion is reflected in an extreme thermal stability in the presence of strong denaturants (1% (w/v) SDS of 6M guanidine): the arms, which are stabilized by intramolecular disulphide bridges, melt around 115°C under non-reducing conditions, whereas the stalk sustains heating up to about 130°C. Complete denaturation of the stalk domain requires treatment with 70% (v/v) sulfuric acid or with fuming trifluoromethanesulfonic acid. The globular protease can be heated to 90°C in 6M guanidine and to 120°C in 1% SDS and represents one of the most stable proteases characterized to date.

- by Andreas Engel
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- Molecular Biology, Transmission/Scanning Electron Microscopy, Molecular, Archaea

The kinetic test of the considered reaction was thermowas studied spectrophotometrically. The reaction was found to stated to {0.05ЊC in a Haake F3 ultrathermostat. The reacfollow a first-order rate law in [ascorbic acid] and an almost first tion flask, containing ascorbic acid in buffered aqueous meorder rate equation in [Se(IV)]. A mechanism was suggested dium, was kept in the thermostat together with a stock soluwhere the rate-determining step is that of the break-up of an tion of selenium dioxide. As the two solutions attained the intermediate complex formed via the ascorbic acid and Se(IV). thermostat temperature, the required volumes of oxidant and The activation parameters have been calculated and discussed. Furthermore, a kinetic test of the reaction was examined by elec-substrate were syringed out and poured into the reaction tron microscope and explained. ᭧ 1996 Academic Press, Inc.

- by AHMED SHAKER
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- Engineering, Kinetics, SEM, Physical sciences

Flagellate protozoa of the hindgut of the xylophagous blattid Parasphaeria boleiriana were examined by light and electron microscopy. This species harbours two oxymonad species of the genera Monocercomonoides and Polymastix, the latter bearing Fusiformis bacteria on its surface. A diplomonad was present and has features of the genus Hexamita rather than Spironucleus. In addition, two trichomonads of the genera Monocercomonas and Tetratrichomastix were identified. A precise comparison with species of blattids and other insects was difficult because most of these flagellates have been described only by light microscopy after cell staining and there are few electron microscope studies and no molecular studies. None of the flagellates contained wood fragments in their food vacuoles and so evidently do not participate in the digestion of wood or cellulose.

- by philippe grandcolas
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- Microbiology, Parasitology, Electron Microscopy, Medical Microbiology

In this paper, we described the use of highpressure carbon dioxide (HPCD) for the inactivation of natural microbes in lychee juice and evaluated its effects on lychee juice quality, compared to a conventional hightemperature, short-time (HTST) method. The HPCD treatments were carried out using a HPCD unit (8 MPa, 36°C, 2 min), and the HTST was performed at 90°C for 60 s. The results showed that five log reduction for yeasts and molds and total aerobic microorganisms occurred at 8 MPa for 2 min. And effects of the treatments on pH and concentrations of microbes, organic acids, titratable acidity (TA), total soluble solid (TSS), sugars, polyphenols, color, and free amino acids were also investigated. HPCD could efficiently maintain the concentration of polyphenols and original color at 8 MPa, 36°C for 2 min. Insignificant differences in colors were observed between unprocessed and HPCD juices, while significant differences were observed between unprocessed and HTST juices. Furthermore, HTST decreased the total free amino acids, whereas HPCD caused a significant increase (increased by 45.92% at 8 MPa) (p \ 0.05). The increase in total amino acids induced by HPCD treatment is beneficial for nutritional value of commercial ready-to-drink lychee juice. In general, HPCD treatment had less influence on the measured quality parameters of lychee juice than HTST treatment. Therefore, HPCD treatment could be a useful alternative to traditional heat treatment.

- by Yuhan Chen
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- High Pressure, Carbon Dioxide, Industrial Biotechnology, Heat Treatment

Fifty bacteriophage isolates of Erwinia amylovora, the causal agent of fire blight, were collected from sites in and around the Niagara region of southern Ontario and the Royal Botanical Gardens, Hamilton, Ontario. Forty-two phages survived the isolation, purification, and storage processes. The majority of the phages in the collection were isolated from the soil surrounding trees exhibiting fire blight symptoms. Only five phages were isolated from infected aerial tissue in pear and apple orchards. To avoid any single-host selection bias, six bacterial host strains were used in the initial isolation and enrichment processes. Molecular characterization of the phages with a combination of PCR and restriction endonuclease digestions showed that six distinct phage types, described as groups 1 to 6, were recovered. Ten phage isolates were related to the previously characterized E. amylovora PEa1, with some divergence of molecular markers between phages isolated from different sites. A study of the host ranges of the phages revealed that certain types were unable to efficiently lyse some E. amylovora strains and that some isolates were able to lyse the epiphytic bacterium Pantoea agglomerans. Representatives from the six molecular groups were studied by electron microscopy to determine their morphology. The phages exhibited distinct morphologies when examined by an electron microscope. Group 1 and 2 phages were tailed and contractile, and phages belonging to groups 3 to 6 had short tails or openings with thin appendages. Based on morphotypes, the bacteriophages of E. amylovora were placed in the order Caudovirales, in the families Myoviridae and Podoviridae. a Asterisk denotes host strain during phage isolation and propagation. wt, wild-type isolate. Rif r , rifampicin-resistant isolate. Str r , streptomycin-resistant isolate.

- by Antonet Svircev
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- Electron Microscopy, Bacteriophages, Biological Control, Multidisciplinary

Swarming motility, a flagellum-dependent behavior that allows bacteria to move over solid surfaces, has been implicated in biofilm formation and bacterial virulence. In this study, light and electron microscopic analyses and genetic and functional investigations have shown that at least 50% of Aeromonas isolates from the species most commonly associated with diarrheal illness produce lateral flagella which mediate swarming motility. Aeromonas lateral flagella were optimally produced when bacteria were grown on solid medium for Ϸ8 h. Transmission and thin-section electron microscopy confirmed that these flagella do not possess a sheath structure. Southern analysis of Aeromonas reference strains and strains of mesophilic species (n ‫؍‬ 84, varied sources and geographic regions) with a probe designed to detect lateral flagellin genes (lafA1 and lafA2) showed there was no marked species association of laf distribution. Approximately 50% of these strains hybridized strongly with the probe, in good agreement with the expression studies. We established a reproducible swarming assay (0.5% Eiken agar in Difco broth, 30°C) for Aeromonas spp. The laf-positive strains exhibited vigorous swarming motility, whereas laf-negative strains grew but showed no movement from the inoculation site. Light and scanning electron microscopic investigations revealed that lateral flagella formed bacteriumbacterium linkages on the agar surface. Strains of an Aeromonas caviae isolate in which lateral flagellum expression was abrogated by specific mutations in flagellar genes did not swarm, proving conclusively that lateral flagella are required for the surface movement. Whether lateral flagella and swarming motility contribute to Aeromonas intestinal colonization and virulence remains to be determined.

- by Ali Rabaan
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- Genetics, Electron Microscopy, Bacteriology, Biological Sciences

The investigation of morphological and structural changes during high energy ball milling and thermal annealing of the mixtures soot-iron and soot-nickel demonstrated that the activation is accompanied by the formation of nano-sized metal particles (10-50 nm) distributed over the amorphous carbon matrix. Prolonged mechanical activation of the amorphous soot-iron system (for more than 3-5 min) leads to the formation of nano-sized cementite Fe C phase. Moreover, mechanical activation of the soot-metal compositions causes 3 a substantial decrease in graphitization temperature of the amorphous carbon: for the soot-iron system, the temperature at which the amorphous carbon starts to crystallize is 250-3008C while for the soot-nickel system, the minimal temperature at which the crystallization of the amorphous carbon was observed exceeded 6008C. Morphological characteristics of the annealed, mechanically activated soot-metal samples depend on the time of preliminary mechanical activation. The annealing of soot-metal samples obtained after short-time mechanical activation (1-3 min) causes a crystallization of the amorphous carbon as onion-like graphite-metal structures. Annealing of the soot / metal samples after mechanical treatment for more than 5 min leads to the formation of metal nanoparticles (40-50 nm) encapsulated by graphite. The longer preliminary mechanical activation, the smaller the size of encapsulated particles. In-situ electron microscopic studies of the interaction of metal particles with amorphous carbon thin film showed that the interaction starts in these systems at temperatures about 6008C. The interaction in the systems iron-amorphous carbon film and nickel-amorphous carbon film proceeds via the formation of the carbide phases Fe C and Ni C; their decomposition results in the formation of crystal carbon and metal 3 3 nanoparticles.

- by B. Bokhonov
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- Materials Engineering, Condensed Matter Physics, Thin Film, Mechanical Alloying

ples as well as a detailed description of the morphological features of these ancient tissues. The intracranial material consisted of well-preserved eosinophilic reticular tissue and, although mostly absent, some exceptional pigment-containing neurons were identified. Conclusions: We present a detailed morphological analysis which can provide valuable information and guidelines for the interpretation of this scarce type of mummified samples and provide explanations for this surprising preservation.

- by Josep M. Fullola and +6
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- Ancient History, Neurology, Paleopathology, Scanning Electron Microscopy

Zoothamnium niveum (Hemprich & Ehrenberg, 1831) Ehrenberg, 1838, a colonial, sessile representative of the Peritrichida (Ciliophora, Oligohymenophora) from the mangrove channels of Twin Cays (Belize Barrier Reef, Caribbean Sea), is remarkable for an obligatory association with ectosymbiotic, chemoautotrophic bacteria. The ultrastructure of the host and the symbiont is investigated by means of low-temperature and conventional scanning electron microscopy, thin section and freeze-fracture transmission electron microscopy. The cortex, the main interface between host and symbiont, differs from the general pattern found in other peritrichs only in having special inclusions of unknown nature and function in the pellicular alveoli. The stationary microzooids and the swarming macrozooids have a fully developed oral ciliature, similar to other peritrichs. The cytopharynx in the macrozooids is highly reduced and no food vacuoles have been detected. Two morphotypes of bacteria, different in size and shape, are present on different parts of the colony and are assumed to represent only one species. The ultrastructural features resemble those of sulfur-oxidizing bacteria. The microzooids feed on bacteria whose size, shape, and ultrastructure is similar to their symbionts. This supports the assumption that Z. niveum gains at least part of its nutrition from chemoautotrophic bacteria.

- by Advin Satriya
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- Microbiology, EM, Medical Microbiology, Pl

The purpose of this study was to determine the effect of freezing process in the absence or presence of excipients on the stability of capsicum loaded nanocapsules (NC) during freeze-thawing and freezedrying procedures. Capsicum loaded nanocapsules were prepared by the modified-emulsion-diffusion method combined with the microfluidization method. The prepared samples were frozen at freezing temperatures of À40, À20, and À15°C to study the effects of cooling temperature on the properties of the capsicum oleoresin loaded nanoparticles. From results, a relatively high freezing temperature had an effect on the maintenance of nanocapsule size after freeze-thawing and freeze-drying. Regarding the addition of excipients, gelatin and j-carrageenan played roles as cryoprotectants and lyoprotectants, and represented R values of 1.01 and 1.13 in size comparisons before and after treatment, respectively. Furthermore, the morphologies of NC made with gelatin or j-carrageenan were conserved after freeze-drying showing spherical forms according to electron microscope observations.

- by Suvimol Surassmo
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- Food Engineering, Food, Stability, Diffusion

The surface modification of powdered tire rubber to increase its adhesion to cement paste was studied. The particles were surface-treated with NaOH saturated aqueous solutions for 20 min. Scanning electron microscopy (S.E.M.), water absorption, density, flexural strength, compressive strength, abrasion resistance, modulus of elasticity and fracture energy measurements were performed using test specimens (water/cement ratio = 0.36) containing 10% of as-received or 10% of NaOH-treated rubber. The results of fracture energy and flexural and compressive strength show that the addition of rubber particles improves the toughness and reduces the porosity of the specimens. Mass loss by abrasion ( À 1.2 0.4% for control specimens; À 1.7 0.4%, using treated rubber and À 4.0 1.2% using as-received rubber, after 600 cycles) and electron microscopic examination show that the NaOH surface treatment enhances the rubber ± matrix adhesion. The use of thus treated tire rubber particles, as addition, instead of a coarse aggregate, in cement-based materials is promising for applications such as driveways or in road construction. D

Seventeen desert tortoises, Xerobates agassizii, with upper respiratory tract disease were examined; thirteen were euthanatized for necropsy. Four normal control desert tortoises from a clinically healthy population were similarly evaluated. Hemoglobin and phosphorus values were significantly (P less than or equal to 0.05) lower and serum sodium, urea, SGOT, and cholesterol values were significantly higher in ill tortoises compared to controls. No significant differences in concentrations of serum or liver vitamins A and E were found between the two groups. While no significant differences were found for concentrations of lead, copper, cadmium, and selenium, the livers of ill tortoises had higher concentrations of mercury and iron. Lesions were found consistently in the upper respiratory tract (URT) of ill tortoises. In all ill tortoises dense infiltrates of lymphocytes and histiocytes obscured the mucosal epithelium and underlying glands. The mucosal epithelium was variably dysplastic, hyperplastic, and occasionally ulcerated. Electron microscopic studies revealed small (350 to 900 nm), pleomorphic organisms resembling Mycoplasma sp., in close association with the surface epithelium of the URT of ill tortoises. Pasteurella testudinis was cultured from the nasal cavity of all ill tortoises and one of four control tortoises. A Mycoplasma sp. was cultured from the nasal passageways of four ill tortoises and was ultrastructurally similar to the pleomorphic organism present on the mucosa in tissue section.

- by Elliott Jacobson
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- Zoology, Electron Microscopy, Scanning Electron Microscopy, Wildlife Diseases

A simple and reliable method has been developed for the in situ LR White embedding of cell monolayers grown on glass cover-slips. Combined with cytochemical or immunological procedures, this technique allows light and/or electron microscopy investigations of a large number of cells in the same horizontal plane within a relatively short period of time. It can be applied to cells grown on microgrid finder cover-slips which allows a distinct site of even an individual cell of a monolayer to be studied at first at the light microscope level and subsequently at the electron microscope level. Hence, it is also suitable for controlling manipulation of single cells, followed by their serial sectioning after relocation in the electron microscope.

- by Wilhelm Mosgoeller
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- Electron Microscopy, Thyroid gland, Melanoma, Horses

From a 1000-year-old mummy, found unwrapped in the sand of the desert at Chiribaya Alta in Southern Peru, two different kinds of tattoos were investigated: decorative tattoos displaying different animals and symbolic ciphers were present... more

- by Maximilian Moser
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- Archaeology, Geochemistry, Electron Microscopy, Archaeological Science

In the study of human hair, medulla is the less studied structure because it is believed that it has no influence on the fibre properties. The aim of this paper is to contribute to the better understanding of medulla morphology. Using reproducible methods for hair samples preparations allowed observing the inner fibre by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Three medulla subunits were observed in cryofractured samples. In addition, the application of plasma etching on samples allowed accessing chemical differences between them. Two kinds of medulla were identified using stereomicroscopy: thin and thick medulla. They were morphologically differentiated using TEM. These methods can be used to study systematically the effects of medulla on hair properties and to evaluate the efficiency of cosmetic products.

The expression of specific calcium binding proteins is being used increasingly as a potential neuroanatomical marker for neurons with similar functions. In this study, the distribution of calbindin D28k in the superior colliculus (SC) of adult hamsters was examined by light and electron microscopy. Calbindin immunoreactivity was prominent in specific regions and laminae of the SC throughout its rostrocaudal extent, and was found to label horizontal, vertical and stellate cell types. In addition, calbindin label highlighted "bridges" of neuronal processes in the intermediate layers. The most frequent calbindin-immunoreactive profiles seen in the electron microscope were dendrites, some of which were post-synaptic to apparent retinal ganglion cell axon terminals. Labelled axons and axon terminals were less frequently encountered. There was considerable overlap between the size distribution of calbindin D28k-immunoreactive neurons and that of GABA-immunoreactive or Nissl stained neurons in the SC. However, using a double fluorescent labelling technique, and examination of the tissue with confocal laser microscopy, no neurons were observed in the hamster SC that showed immunoreactivity for both catbindin and GABA. In this regard, the SC is similar to the mammalian lateral geniculate nucleus and the pretectum, but differs from the neocortex, where calbindin and GABA are colocalized. The demonstration in the SC, as well as other parts of the nervous system, of sub-populations of neurons that contain distinct calcium-binding proteins suggests that these neurons have different functional properties. Correlative studies may clarify the relevance of these cytoplasmic components as cell markers, as well as their different patterns of association with neurotransmitters and peptides.

- by Garth Bray
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- Electron Microscopy, Immunohistochemistry, Neurons, Superior Colliculus

The resolution value claimed for an electron microscopical three-dimensional reconstruction indicates the overall quality of the experiment. The Fourier shell correlation (FSC) criterion has now become the standard quality measure. However, what has continued to be controversial is the issue of the FSC threshold level at which one defines the reproducible resolution. Here, we discuss the theoretical behaviour of the FSC in conjunction with the various factors which influence it: the number of ''voxels'' in a given Fourier shell, the symmetry of the structure, and the size of the structure within the reconstruction volume. Both the theoretical considerations and our model experiments show that fixed-valued FSC threshold (like ''0.5'') may never be used in a reproducible criterion. Fixed threshold values are-as we show here-simply the result of incorrect assumptions in the basic statistics. Two families of FSC threshold curves are discussed: the r-factor curves and the new family of bit-based information threshold curves. Whereas r-factor curves indicate the resolution level at which one has collected information significantly above the noise level, the information curves indicate the resolution level at which enough information has been collected for interpretation.

- by Marin Van Heel
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- Structural Biology, Information, Fourier Analysis, Computer Simulation

This paper focuses on the determination of the statistical correlation between yarn diameter and yarn linear mass. The experimental methods employed are based on optical analysis and on image processing techniques applied to electron microscope images. Several different cotton yarns were examined over a wide range of yarn linear masses. The results indicate that diameters predicted by the relationship commonly quoted in the literature can be as much as 62% smaller than those experimentally observed.

- by Filomena Soares and +1
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- Materials Engineering, Nondestructive Evaluation, Experimental, Experimental Method

Recent molecular analyses consistently resolve the "spoon worms" (Echiura) as a subgroup of the Annelida, but their closest relatives among annelids still remain unclear. Since the adult morphology of echiurans yields limited insight into their ancestry, we focused on characters of their larval anatomy to contribute to this discussion. Electron microscopical studies of the larval protonephridia (so-called head kidneys) of the echiuran species Thalassema thalassemum revealed distinct correspondences to character states in serpulid polychaetes, although a close relationship between Echiura and Serpulidae is not supported by any phylogenetic analysis. The larval head kidneys of T. thalassemum consist of only two cells, a terminal cell and a duct cell. The terminal cell forms a tuft of six cilia projecting into the lumen of the terminal cell. The cilia are devoid of circumciliary microvilli. A Wlter structure is formed by two to three layers of elongate microvilli that surround the lumen of the terminal cell in a tubular manner. A thin layer of extracellular matrix (ECM) encloses the outer microvilli of the tubular structure. The tips of the microvilli project into the lumen of the adjacent duct cell but are not directly connected to it. However, mechanic coupling is facilitated by the surrounding ECM and abun-dant hemidesmosomes. The distal end of the multiciliary duct cell forms the external opening of the nephridium; a specialized nephropore cell is absent. Apart from the multiciliarity of the duct cell, details of the head kidneys in T. thalassemum reveal no support for the current assumption that Echiura is closely related to Capitellida and/or Terebelliformia. Available data for other echiuran species, however, suggest that the head kidneys of T. thalassemum show a derived state within Echiura.

- by Björn Quast
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- Zoology, Extracellular Matrix, Close relationships, Phylogenetic analysis

Jojoba oil is of immense importance for industrial applications. There are a lot of published articles concerning its various uses in cosmetics, detergents, surfactants and lubricants. Therefore, this work was devoted to exploring its application for further use in the leather industry as a fat-liquoring agent. The fat-liquoring process is one important step in leather manufacturing, with the intention of obtaining leather of full, soft handle, flexibility, and pliability as well as improving its mechanical properties. The study involved preparation of jojoba fatliquor via a sulfitation process. An improvement of the sulfitation process based on combined SO 3 content was achieved under phase transfer catalysis (PTC). Two differently prepared types of phase transfer catalyst of phosphonium and ammonium types were investigated, namely, benzyl tri-phenyl phosphonium chloride (BTPP) and triethyl benzyl ammonium chloride (TEBA). The fat-liquored leather led to an improvement in its mechanical properties such as tensile strength and elongation at break. In addition, a significant enhancement of the texture of the treated leather by jojoba fat-liquor as indicated in the scanning electron microscope (SEM) images was observed.