ER Profiles Research Articles

Loss of the Atp2c1 Secretory Pathway Ca2+-ATPase (SPCA1) in Mice Causes Golgi Stress, Apoptosis, and Midgestational Death in Homozygous Embryos and Squamous Cell Tumors in Adult Heterozygotes

Loss of one copy of the human ATP2C1 gene, encoding SPCA1 (secretory pathway Ca(2+)-ATPase isoform 1), causes Hailey-Hailey disease, a skin disorder. We performed targeted mutagenesis of the Atp2c1 gene in mice to analyze the functions of this Golgi membrane Ca(2+) pump. Breeding of heterozygous mutants yielded a normal Mendelian ratio among embryos on gestation day 9.5; however, null mutant (Spca1(-/-)) embryos exhibited growth retardation and did not survive beyond gestation day 10.5. Spca1(-/-) embryos had an open rostral neural tube, but hematopoiesis and cardiovascular development were ostensibly normal. Golgi membranes of Spca1(-/-) embryos were dilated, had fewer stacked leaflets, and were expanded in amount, consistent with increased Golgi biogenesis. The number of Golgi-associated vesicles was also increased, and rough endoplasmic reticulum had fewer ribosomes. Coated pits, junctional complexes, desmosomes, and basement membranes appeared normal in mutant embryos, indicating that processing and trafficking of proteins in the secretory pathway was not massively impaired. However, apoptosis was increased, possibly the result of secretory pathway stress, and a large increase in cytoplasmic lipid was observed in mutant embryos, consistent with impaired handling of lipid by the Golgi. Adult heterozygous mice appeared normal and exhibited no evidence of Hailey-Hailey disease; however, aged heterozygotes had an increased incidence of squamous cell tumors of keratinized epithelial cells of the skin and esophagus. These data show that loss of the Golgi Ca(2+) pump causes Golgi stress, expansion of the Golgi, increased apoptosis, and embryonic lethality and demonstrates that SPCA1 haploinsufficiency causes a genetic predisposition to cancer.

Discrepancy between modelled and measured radial electric fields in the scrape-off layer of divertor tokamaks: a challenge for 2D fluid codes?

Examination of radial electric field (Er) profiles in the scrape-off layer (SOL) of ASDEX Upgrade (AUG) and JET revealed large discrepancies between 2D fluid edge modelling and experiment. Experimental profiles of plasma potential (Vp) in the outer (low field) side of the plasma, obtained with reciprocating Langmuir probes, decay radially with electron temperature, Te, with the −eEr/∇Te ratio being > 1.5. In contrast, code simulated Er are fairly low in most of the SOL (compared with −∇Te/e). Modelling with kinetic treatment of neutrals and drifts was performed using the SOLPS code for AUG cases and EDGE2D-Nimbus for JET cases.Mismatches between modelled and experimental Er may be caused by the recently established tendency for the SOLPS code to underestimate Te in the divertor of AUG. It was attributed to non-locality of parallel transport of supra-thermal, heat-carrying electrons originating upstream of the divertor, which are usually only weakly collisional and can penetrate, with few collisions, to the target. Ratios −eEr/∇Te obtained from the probe measurements in JET are of order 1.6, while in AUG, JT-60U and TCV they are of order 3. Such high values point to the possibility of fast electrons contributing, apart from target heat fluxes, also to the formation of the Debye sheath.The problem of the underestimation of Er in the codes must be closely related with the well-known problem of the underestimation of those parts of parallel ion flows in the SOL that are influenced by the toroidal field direction. It was demonstrated earlier that parallel ion flow at the outer midplane is dominated by the ion Pfirsch–Schlüter flow, which in turn is partly driven by the radial electric field. The Te and Er discrepancies, as well as discrepancies between simulated and experimental parallel ion flows, raise a question of the validity of fluid codes for the plasma edge modelling and prompt the inclusion of kinetic effects into present-day 2D fluid codes which assume strong collisionality.

RBS, PIXE and NDP study of erbium incorporation into glass surface for photonics applications

This paper reports on the fabrication and the characterisation of successful erbium in-diffusion into silicate glass surface for potential use in photonics active structures through ion beam analytical methods. The erbium doping occurred by ion exchange of erbium ions from a molten source for lithium ions from the specially designed glass substrates. Composition of the optical layers was studied by ion beam analytical techniques: RBS (Rutherford backscattering spectroscopy) characterized depth distribution of the incorporated Er3+ ions and PIXE (particle induced X-ray emission spectroscopy) gave information on the total amount of erbium incorporated in the samples. The NDP (neutron depth profiling) method was used to evaluate changes in distribution of Li+ ions in the surfaces of the fabricated samples. We observed shallow Er profiles that were accompanied by more mobile Cs+, Rb+ ions incorporated in the much deeper layer as compared to the Er. The Li concentration in the glass substrate occurs as the most important parameter for Er diffusion into the glass substrate.

Measurement of the nonlinear coefficient of telecommunication fibers as a function of Er, Al, and Ge doping profiles by using the photorefractive beam-coupling technique

We have used the photorefractive two-beam-coupling technique to measure the nonlinear coefficient (n_2/A_eff) of several telecommunication fibers and investigated the dependence of n_2/A_eff on Er, Al, and Ge doping profiles in single-mode fibers, where n_2 is the nonlinear refractive index and A_eff is the effective area of the LP_01 mode. A semiempirical relation is derived for predicting the value of n_2/A_eff as a function of Er, Al, and Ge content in optical fibers. We have further examined the wavelength dependence of A_eff in pure and doped silica fibers between 1064 and 1552 nm and found that the A_eff value of doped fibers changes more markedly with wavelength than that of pure-silica fibers.

Stability of erbium and silver implanted in silica–titania sol–gel films

We implanted silica–titania sol–gel films with 3×1015at./cm2, 180keV Er+ and 6×1016at./cm2, 140keV Ag+ ions. The energies were chosen so that the profiles of Ag and Er overlap. RBS and ERDA were used to study the behaviour of Ag, Er and H during the heat treatments used to densify the films. Implantation causes H depletion at the film surface and an increase in H concentration just beneath the implanted Ag and Er profiles. The total H content decreases by 27% to 75% during implantation. During annealing the H content decreases, with an almost complete H loss after annealing for 35min at 800°C. The Ag profile remains stable up to 600°C. Above 700°C Ag becomes increasingly mobile. Annealing at 800°C for 35min results in a nearly constant Ag distribution in the film. The Er profile remains unchanged with heat treatment up to the maximum temperature used (800°C).

Redistribution of Er implanted into Si(1 0 0): Correlation with implantation induced damage

The redistribution of Er in Si is studied by annealing samples of Si implanted with 200 keV Er at doses 5 × 10 14 and 3.2 × 10 15 ions/cm 2, respectively. Er profiles are measured by secondary ion mass spectrometry and implantation induced damage by cross-sectional transmission electron microscopy. A continuous amorphous layer is formed extending from surface to the end of range for the as-implanted high dose sample which recrystallizes by solid phase epitaxial process with substantial [1 1 1] twins and {1 1 1} stacking faults near the surface region after annealing at 900 °C for 30 min. The high dose sample after annealing is characterised by Er trapping of maximum concentration of 8 × 10 19/cm 3 at the heavily twinned recrystallized region with a decreased concentration at the surface. On the other hand the low dose sample after annealing shows Er segregation of concentrations up to 3 × 10 20/cm 3 at the surface.

Nectar resorption in the spur of Platanthera chlorantha Custer (Rchb.) Orchidaceae – structural and microautoradiographic study

In the flowers of Platanthera chlorantha nectar is secreted and accumulated in a spur. Previous studies of this species revealed that after the period of secretion and cessation, rapid nectar resorption occurs. The aim of this study was the observation of nectar resorption on the structural level using tritium labelled sucrose. For this purpose, during the peak of nectar secretion, 10 μl of nectar accumulated in the spur was replaced with the same volume of labelled sucrose (10 μCi). Small fragments of spurs were sampled between 12–36 h of incubation, at the resorption phase. Afterwards, they were fixed and embedded in epoxy resin. Material for the microautoradiographic study was prepared with the dipping technique. The cells of secretory epidermis and unicellular secretory papillae had dense, strong stained cytoplasm, a large nucleus and small vacuoles. A characteristic feature of these cells was the presence of numerous starchless plastids, mitochondria and ER profiles. Many vesicles occurred in the close vicinity of the cell wall. In the cuticle covering cell walls no pores or cracks were observed. Presence of [3H] sucrose was detected mainly in the walls of the nectary cells, which would indicate an apoplastic route of resorbed nectar.

Development of cell wall modifications in the endodermis and exodermis of Allium cepa roots

The cytological events of wall modification in the endodermis and exodermis of Allium cepa L. roots were examined with fluorescence and transmission electron microscopy. In the endodermis, Casparian bands, suberin lamellae, and tertiary walls developed in succession. At the site of the future Casparian band, the plasma membrane was bound to the wall before deposition of detectable hydrophobic components in the radial wall. Suberin lamellae were deposited on the inner faces of the primary walls, first along the outer tangential walls and then the inner tangential walls. On both walls, segments of the lamellae were formed earlier in primary pit fields than at nonprimary pit field regions. Suberin lamellae then extended to the radial walls. When they reached the Casparian bands, the lamellae intruded between the bound plasma membranes and the walls, so that the cells' plasma membranes remained intact. In this way, suberin lamellae that were continuous around the cells were laid down. Later, tertiary walls were deposited internal to the suberin lamellae. None of the wall modifications interrupted the symplastic connections of the endodermis. During suberin lamella and tertiary wall formation, more dictyosomes and ER profiles appeared than during Casparian band development. In the exodermis, although Casparian bands were readily detected with fluorescence microscopy, they were rarely detected with electron microscopy. Suberin lamellae were formed in long cells severing their plasmodesmata. As in the endodermis, dictyosomes and ER were prominent during suberin lamella formation. Tertiary walls were not formed in the exodermis.Key words: Allium cepa, Casparian band, endodermis, exodermis, suberin lamella, ultrastructure.

Simultaneous measurement of q and Er profiles using the motional Stark effect in high-performance DIII-D plasmas (invited)

The motional Stark effect (MSE) diagnostic was developed to provide a measurement of the magnetic pitch angle or q profile in tokamaks. The technique relies upon polarization measurements of Stark broadened Dα emission to determine the pitch angle of the Lorentz vb×B electric field, where vb is the injected neutral beam particle velocity and B is the total magnetic field. However, in many advanced confinement regimes, large values of the plasma radial electric field, Er, are observed and can affect the interpretation of MSE measurements. Viewing fixed locations in the plasma from two different viewing angles allows one to separate the Er field from the vb×B field, thus providing simultaneous measurement of the Er and q profiles. To achieve this measurement, the DIII–D MSE diagnostic was recently upgraded from 16 to 35 channels with three independent viewing angles. The new instrument provides an Er resolution of 5–10 kV/m with a time response of 1 ms. Measurement results from the VH mode, reverse shear, and H mode plasmas are presented.

A unified theory of transport barriers and of subneoclassical transport

“Subneoclassical” heat fluxes are shown to be rigorous consequences of the revisited neoclassical theory published earlier [Phys. Plasmas 1, 619 (1994)]. Including finite Larmor radius and inertia effects, this theory also provides a nondegenerate ambipolarity constraint, which, together with the parallel momentum equation, defines unambiguously the radial electric field Er and the parallel velocity U∥,i. It is shown that the stationary solution of those equations features, under conditions that are discussed, highly sheared Er profiles as observed in edge transport barriers. The operation regime is determined by a competition between nonlinear spin up of the rotation (which is interpreted) and momentum loss via charge exchange neutrals. The position of the transport barrier—near the last closed magnetic surface (LCMS)—is explained. The local threshold condition is analyzed, including the role of recycling neutrals and of the isotope mass. The width of the shear layer, as well as the predicted jumps and negative values of Er in front of the LCMS, agrees with experimental data. The time-dependent equations have solutions propagating from the edge to the core; the time scale associated with the toroidal rotation scales as and is usually comparable to the neoclassical heat transport time scale. Although the theory is so far limited to the high collisionality regime, a clear physical interpretation of the results allows extrapolation to low collisionality plasmas.

Endoplasmic reticulum derived decorated tubules in the sieve elements ofNymphaea

Bundles of decorated tubules found in the sieve elements ofNymphaea have been studied with the transmission electron microscope. Comparatively straight tubules (100 nm in diameter) arise from the endoplasmic reticulum during early stages of sieveelement development and subsequently associate into bundles of up to 100 tubules that parallel the longitudinal cell axis. From the start of their formation the tubules are structurally distinct from other ER profiles due to their dense decoration with particles. High magnifications reveal an orderly array of the particles (about 24 surround a 100 nm tubule) and suggest a modification of their membrane so that it is no longer dissolvable into a regular three-layered structure. Later during sieve-element ontogeny the decorated tubules get invaginated by smooth ER membranes, thereby squeezing out the intratubular (extracytoplasmic) space. As a result a double mantle is formed that surrounds a plasmatic cylinder. Decorated 100 nm tubules with inner membranes are present in enucleate mature sieve elements ofNymphaea alba andN. tuberosa. Considerably larger tubules (about 200 nm in diameter) were found inN. Candida andN. tetragona and occasionally also inNuphar and Barclaya, two other genera from the same family. The decoration of the tubules and their subsequent invagination by smooth membranes are discussed with respect to the controlled autolysis of sieve elements.

Pollen and Tapetum Development in Male FertileRosmarinus OfficinalisL. (Lamiaceae)

Abstract The development of microspores/pollen grains and tapetum was studied in fertile Rosmarinus officinalis L. (Lamiaceae). Most parts of the cell walls of the secretory anther tapetum undergo modifications before and during meiosis: the inner tangential and radial cell walls, and often also the outer tangential and radial wall, acquire a fibrous appearance; these walls become later transformed into a thin poly-saccharidic film, which is finally dissolved after microspore mitosis. Electron opaque granules found within the fibrous/lamellated tapetal walls consist of sporopollenin-like material, but cannot be interpreted as Ubisch bodies. The middle lamella and the primary wall of the outer tangential and radial tapetal walls remain unmodified, but get covered by an electron opaque, sporopollenin-like layer. Pollenkitt is formed only by lipid droplets from the ground plasma and/or ER profiles, the plastids do not form pollenkitt precursor lipids. Tapetum maturation (“degeneration”) does not take place before late vacuolate stage. The apertures are determined during meiosis by vesicles or membrane stacks on the surface of the plasma membrane. The procolumellae are conical, but at maturity the columellae are more cylindrical in shape. The columellar bases often fuse, but a genuine foot layer is lacking. The formation of the endexine starts with sporopollenin-accumulating white lines adjacent to the columellar bases. Later, the endexine grows more irregularly by the accumulation of sporopollenin globules. In mature pollen the intine is clearly bilayered. Generative cells (GCs) and sperm cells contain a comparatively large amount of cytoplasm, and organelles like mitochondria, dictyosomes, ER, and multi-vesicular bodies, but no plastids; GCs and sperms are separated from the vegetative cell only by two plasma membranes.

Development of a Tokamak Plasma Optimized for Stability and Confinement

Design of an economically attractive tokamak fusion reactor depends on producing steady-state plasma operation with simultaneous high energy density ({beta}) and high energy confinement ({tau}{sub E}); either of these, by itself, is insufficient. In operation of the DIII-D tokamak, both high confinement enhancement (H{equivalent_to} {tau}{sub E}/{tau}{sub ITER-89P} = 4) and high normalized {beta} ({beta}{sub N}{equivalent_to} {beta}/(I/aB) = 6%-m-T/MA) have been obtained. For the present, these conditions have been produced separately and in transient discharges. The DIII-D advanced tokamak development program is directed toward developing an understanding of the characteristics which lead to high stability and confinement, and to use that understanding to demonstrate stationary, high performance operation through active control of the plasma shape and profiles. The authors have identified some of the features of the operating modes in DIII-D that contribute to better performance. These are control of the plasma shape, control of both bulk plasma rotation and shear in the rotation and Er profiles, and particularly control of the toroidal current profiles. In order to guide their future experiments, they are developing optimized scenarios based on their anticipated plasma control capabilities, particularly using fast wave current drive (on-axis) and electron cyclotron current drive (off-axis). The most highly developed model is the second-stable core VH-mode, which has a reversed magnetic shear safety factor profile [q(O) = 3.9, q{sub min} = 2.6, and q{sub 95} = 6]. This model plasma uses profiles which the authors expect to be realizable. At {beta}{sub N} {>=} 6, it is stable to n=l kink modes and ideal ballooning modes, and is expected to reach H {>=} 3 with VH-mode-like confinement.

MeV Ion Implantation of Er into LiNbO3

ABSTRACTThe incorporation of Er into LiNbO3 is of great interest for fabricating waveguide lasers and amplifiers. We compare Er diffusion data with the results of Er implantation, performed at 3.6 MeV energy. Even after annealing for 4h at 1060°C, the resulting Er profiles display very good matching to the optical modes. The results of a theoretical gain estimate are presented.

The transmitting tract in Trimezia fosteriana (Iridaceae).

Observations of the transmitting tract cells in Trimezia fosteriana were made from the pre‐secretory stage until anthesis. Secretory products appear about 14 days before anthesis in all parts of the pistil. Simultaneously starch disappears from the plastids and the dictyosomes are surrounded by more and larger vesicles than before. In the beginning of the secretory stage multivesicular bodies may be in contact with ER profiles and an ER origin is therefore presumed. Later during the secretory stage the multivesicular bodies are larger and more abundant. Their envelope is often partly fused with the plasma membrane and vesicle swarms are common on the outside of it. Close to flower opening many organelles change in appearence. RER becomes more abundant and the mitochondrial matrix highly electron dense and the cristae expanded. Starch grains reappear and large ones are common in the stigma and ovary plastids. The dictyosomes are numerous and surrounded by the largest vesicles observed during the secretory stage. Osmiophilic granules are common in the dictyo‐some vesicles and under the cell walls abutting the transmitting tract. In the ovary they are present one week before anthesis. In the stigma and style corresponding granules of high electron density appears at the day of flower opening. The extracellular secretory product contains fibrillar and granular substances consisting of carbohydrates, including pectic substances, and proteins.

Metabolism of P-particles (polysaccharide particles) in mature pollen grains ofEryngium campestre L. (Apiaceae)

The metabolism of P-particles (polysaccharide particles) was investigated in mature pollen grains ofEryngium campestre L. Numerous P-particles, originating from dictyosome activity, are found to be accumulated near the apertures, followed by mitochondria. A single layer of ER profiles seems to prevent the fusion of the P-particles with the intine. Instead of this, they fuse with each other forming nonmembrane-bounded polysaccharide-aggregates, which subsequently change their granulated structure to an amorphous. Mitochondria together with small vesicles are involved in the conversion-process. The so formed wall precursors pass through the ER and fuse into the intine.

Structure and cytochemistry of the procambium in Salix buds during dormancy and dormancy breaking

This report presents a combined investigation of ultrastructural and enzymatic changes in the procambium from late winter to early spring. In January the procambial cells of dormant Salix buds have a convoluted plasma membrane with many plasmalemmasomes, numerous lipid bodies, large stacks of rough ER and plastids surrounded by smooth ER profiles. Several small lysosomes show activity of ATPase and acid phosphatases. In addition ER, nuclear envelopes, dictyosomes, and thylakoids have ATPase activity, and ER and plasmalemma, and nuclei also show acid phosphatase activity. In February metabolism seems to increase as indicated by lysosomes with membranous formations, dilated ER, nuclear envelopes, spiny vesicles, and polysomes. ATPase activity occurs in plasmalemma and vacuoles, and acid phosphatases in the middle lamella region of walls, in plasmalemma, vacuoles, ER, and nuclei. At the end of March, when growth starts inside the buds, but before they break, the stacks of rough ER disappear, and the vacuoles coalesce. Most of the lipid bodies have disappeared and the plastids have accumulated starch. Cell division and differentiation of procambial cells to protophloem and protoxylem have started. The distribution of ATPase increases; activity is found in walls and plasmalemma, and only a few small vacuoles still have ATPase and acid phosphatase activity. Notable is the appearance of ATPase in mitochondrial cristae and nucleoli and the occurrence of rather high levels also in endomembranes and dictyosomes.

Electron-dense endoplasmic reticulum-like profiles closely associated with mitochondria in glomus cells of the carotid body after fixation with oxalate

Fixation in the presence of oxalate was used to demonstrate the electron-dense Ca 2+ precipitates in the endoplasmic reticulum in glomus cells of the carotid body. Glomus cells in intact carotid bodies or cells dissociated from the organ by treatment with collagenase were studied electron microscopically. In the intact organ as well as in dissociated glomus cells, electron-dense endoplasmic reticulum-like profiles were seen closely associated with mitochondria, while these lacked reaction product. The interspace between mitochondria was occupied by electron-dense, slightly distended ER, which appeared to contact the outer membrane of the mitchondria. Occasionally, a mitochondrion was in contact with several ER profiles or the ER formed an electron-dense ‘cap’ on the mitochondrion. The electron-dense precipitates could be removed from ultrathin sections with the calcium chelator ethyleneglycol-2(2-aminoethyl tetra-acetic acid) (EGTA). It is tentatively suggested that the endoplasmic reticulum could be involved in intracellular buffering of Ca 2+ in the glomus cell, as has been previously suggested for neurons.

The effect of starvation and subsequent feeding on the hepatocytes of Chanos chanos (Forsskal) fingerlings and fry

Excised liver sections of the milkfish, Chanos chanos, fry and fingerlings were studied by transmission electron microscopy. The hepatocytes underwent marked ultrastructural alterations in response to food deprivation of 10‐day starvation for fry and 2 months for the fingerlings. The prominent features characterizing the hepatocytes of starved fish were: a reduction of cell and nucleus size; apparent loss of nucleoli; condensation of chromatin material in fry; loss of stored glycogen; reduction of ER profiles; increase in the number of electron‐dense bodies containing large amounts of iron in fingerlings; and an increase in mitochondrial size. These changes were reversible following short periods of re‐feeding, i.e. 2 days for fry and 4 days for fingerlings, using natural food for the fry and formulated diet for the fingerlings.

Fine structure of the leaf epidermis of Thalassodendron ciliatum (Forsk.) den Hartog

Ultrastructural features of leaf blade epidermal cells of the marine angiosperm Thalassodendron ciliatum (Forsk.) den Hartog are described. The cells resemble transfer cells since they possess a highly invaginated plasmalemma with which numerous mitochondria are often associated. However, wall ingrowths as known in transfer cells of terrestrial plants, are absent. The plasmalemma is investigated around loosely-distributed fibrillar material present within a labyrinthine extracytoplasmic space. This material differs from the material that comprises the cell walls. The cytoplasm of the cells is rich in ribosomes. As in epidermal cells of other marine angiosperms, chloroplasts feature prominently. Other cytoplasmic components include microbodies, lipid droplets, unusual membrane-bound spherical osmiophilic bodies, and relatively few microtubules, dictyosomes and ER profiles. A thin, but distinct cuticle covers the leaf surface. The outer tangential cell wall is about twice as thick as the other walls and has an interesting structure; the innermost portion of this wall often stains more intensely than the rest of the wall; wall striations, adjacent to this intensely-staining layer, are more prominent here than in the other walls; certain layers of the striated portion of the wall appear to have a porous texture; and cavities, generally similar to the subcuticular cavities of the marine angiosperm Zostera capensis Setchell, occur in the midregion of the wall, as well as beneath the cuticle. An extremely small opening is found in the cuticle that overlies a subcuticular cavity. The presence of an enlarged plasmalemma, a fenestrated cuticle and a partially porous outer wall suggests that these cells probably participate in absorptive and/or secretory or excretory processes.