Fine Tube Research Articles

1P-129 管周囲が一個の上皮細胞からなる細い管の形成(発生分化,第46回日本生物物理学会年会)

1P-129 管周囲が一個の上皮細胞からなる細い管の形成(発生分化,第46回日本生物物理学会年会)

P‐65: Plasma Parameters of Gas Discharge in Cold Cathode Fluorescent Lamps and External Electrode Fluorescent Lamps

AbstractFrom the light propagation observed along the tube of CCFLs and EEFLs, the electron temperature and the plasma density are estimated as kTe∼2 eV and ne∼1016 m−3. This might be a new diagnostic technology to measure the plasma parameters in the fine tube of gas discharge.

High Mucosal Serotonin Availability in Neonatal Guinea Pig Ileum Is Associated With Low Serotonin Transporter Expression

5-Hydroxytryptamine (5-HT) is a neurotransmitter and paracrine signaling molecule in the gut. Paracrine signaling by enterochromaffin cells (EC), which release 5-HT, has not been studied in neonates. Our aim was to compare 5-HT disposition in the intestinal mucosa of neonatal and adult guinea pigs. 5-HT was locally measured in vitro from intestinal segments using a diamond microelectrode and continuous amperometry. The serotonin transporter (SERT) was measured using immunohistochemical and Western blot techniques. 5-HT intestinal content was measured using immunohistochemistry and high-performance liquid chromatography with electrochemical detection. An oxidation current, reflective of local 5-HT release, was recorded with the microelectrode near the mucosal surface, and this current was larger in neonatal than in adult tissues. Mechanically stimulating the mucosa with a fine glass probe evoked an additional current in adult but not neonatal tissues. Oxidation currents were reduced by tetrodotoxin and were blocked in calcium-free solutions. Fluoxetine (1 microM) potentiated oxidation currents in adult but not neonatal tissues. SERT levels were lower in neonatal vs adult tissues. There was no difference in 5-HT content between neonates and adults but 5-hydroxyindole acetic acid/5-HT ratios were higher in adults. EC cell counts showed no difference in cell number, but EC cells were found in the crypts in neonatal and along the villi in adult tissues. SERT expression is low in neonates, and this is associated with high levels of free mucosal 5-HT and reduced metabolism. Postnatal maturation of 5-HT signaling may be important for development of neurohumoral control of intestinal motor reflexes.

Diffusioosmosis of Electrolyte Solutions in a Fine Capillary Tube

A theoretical study is presented for the steady diffusioosmotic flow of an electrolyte solution in a fine capillary tube generated by a constant concentration gradient imposed in the axial direction. The capillary wall may have either a constant surface potential or a constant surface charge density of an arbitrary quantity. The electric double layer adjacent to the charged wall may have an arbitrary thickness, and its electrostatic potential distribution is determined by an analytical approximation to the solution of the Poisson-Boltzmann equation. Solving a modified Navier-Stokes equation with the constraint of no net electric current arising from the cocurrent diffusion, electric migration, and diffusioosmotic convection of the electrolyte ions, the macroscopic electric field and the fluid velocity along the axial direction induced by the imposed electrolyte concentration gradient are obtained semianalytically as a function of the radial position in a self-consistent way. The direction of the diffusioosmotic flow relative to the concentration gradient is determined by the combination of the zeta potential (or surface charge density) of the wall, the properties of the electrolyte solution, and other relevant factors. For a prescribed concentration gradient of an electrolyte, the magnitude of fluid velocity at a position in general increases with an increase in its distance from the capillary wall, but there are exceptions. The effect of the radial distribution of the induced tangential electric field and the relaxation effect due to ionic convection in the double layer on the diffusioosmotic flow are found to be very significant.

Development of the fine artifical blood tube by cocoon filaments

Development of the fine artifical blood tube by cocoon filaments

Analysis of refractive artifacts by reconstructed three-dimensional ultrasound imaging.

Refractive artifacts are frequently encountered in clinical settings, and they have been analyzed on the basis of conventional two-dimensional (2-D) ultrasound (US) images, but this method is restricted to monoplane data and is limited by its inability to assess the three-dimensional (3-D) structure of refractive artifacts. The aim of this study was to evaluate the role of reconstructed 3-D US images in the analysis of refractive artifacts. The following representative refractive artifacts were analyzed on the basis of reconstructed 3-D US images: (a) a distorted image of a fine tube behind a cyst (balloon); (b) a deformed image of the bottom of a balloon; and (c) a duplication artifact due to the acoustic lens effect. (a) A tube was imaged as a fine echogenic line with two points of sudden interruption, unlike a curved needle, which was imaged without interruption. (b) 3-D US allowed us to visualize the mode of deformity in the image of the bottom of a fluid-filled balloon in a water bath. When the acoustic velocity in the fluid was greater than that in the surrounding water, the bottom of the balloon appeared to be shrunken. When the acoustic velocity in the fluid was less than that in the surrounding water, the bottom of the balloon appeared to be swollen. (c) When we placed two pieces of white chicken meat in front of a fine needle, the needle was duplicated in the resulting image. In this case, the needle appeared to be vague and fuzzy. In this case, 3-D US did not add further information to the 2-D images. Our study suggests that reconstructed 3-D US images provide a better understanding of the mode of refractive artifacts than do 2-D US images.

1A1-C31 静電インクジェットを用いたマスクレス回路描画技術の開発

We have been developing a mask-less printing technology for microelectronic circuits utilizing an electrostatic inkjet system. Drops of paste that contained Ag nano-particles were injected on a substrate by the electrostatic force to form electrode patterns. The formation of the drop was controlled by the application of pulse voltage between the plate electrode and a fine tube that contains Ag paste. It was demonstrated that line electrodes of 200 μm pitch were successfully printed on a glass substrate. A multi-layered printing was also realized by overcoating glass paste on the electrode.

Microgravity experiments on flame spread along fuel-droplet arrays using a new droplet-generation technique

A new droplet-array generation technique achieved high quality and high reliability in microgravity experiments on multiple-droplet combustion. Each fuel droplet formed at the intersection of fine, X-shaped SiC fibers when liquid fuel was supplied through a fine glass tube. We aligned several sets of these X-shaped fibers and their corresponding fine glass tubes to form a droplet array. All the droplets in the array were simultaneously generated in a short time. In flame-spread experiments, a hot-wire igniter ignited an end droplet to initiate the flame spread along the array. We demonstrated microgravity experiments of droplet array combustion using the new droplet-array generation technique at a drop-experiment facility, MGLAB, in Japan. We successfully generated large droplets, which often fell off the fiber intersection in normal gravity, by using this method in microgravity. This technique is also effective in droplet-array combustion experiments using high-volatility fuel, where prevaporization is substantial. We compared the flame-spread rate and the flame-spread limit of these linear droplet arrays with results of an existing experiment, and discussed the effects of the suspending fiber on the flame spread.

Effects of L-arginine on serum nitric oxide, nitric oxide synthase and mucosalNa+-K+-ATPaseand nitric oxide synthase activity in segmental small-bowel autotransplantation model

To explore a simple method to create intestinal autotransplantation in rats and growing pigs and to investigate the effect of L-arginine supplementation on serum nitric oxide (NO), nitric oxide synthase (NOS) and intestinal mucosal NOS and Na+-K+-ATPase activity during cold ischemia-reperfusion (IR) in growing pigs. In adult Wistar rat models of small bowel autotransplantation, a fine tube was inserted into mesenteric artery via the abdominal aorta. The superior mesenteric artery and vein were occluded. Isolated terminal ileum segment was irrigated with Ringer's solution at 4 degrees and preserved in the same solution at 0-4 degrees for 60 min. Then, the tube was removed and reperfusion was established. In growing pig models, a terminal ileum segment, 50 cm in length, was isolated and its mesenteric artery was irrigated via a needle with lactated Ringer's solution at 4 degrees. The method and period of cold preservation and reperfusion were described above. Ten white outbred pigs were randomly divided into control group and experimental group. L-arginine (150 mg/kg) was continuously infused for 15 min before reperfusion and for 30 min after reperfusion in the experimental group. One, 24, 48, and 72 h after reperfusion, peripheral vein blood was respectively collected for NO and NOS determination. At the same time point, intestinal mucosae were also obtained for NOS and Na+-K+-ATPase activity measurement. In adult rat models, 16 of 20 rats sustained the procedure, three died of hemorrhage shock and one of deep anesthesia. In growing pig models, the viability of small bowel graft remained for 72 h after cold IR in eight of 10 pigs. In experimental group, serum NO level at 1 and 24 h after reperfusion increased significantly when compared with control group at the same time point (152.2+/-61.4 micromol/L vs 60.8+/-31.6 micromol/L, t=2.802, P=0.02<0.05; 82.2+/-24.0 micromol/L vs 54.0+/-24.3 micromol/L, t=2.490, P=0.04<0.05). Serum NO level increased significantly at 1 h post-reperfusion when compared with the same group before cold IR, 24 and 48 h post-reperfusion (152.2+/-61.4 micromol/L vs 75.6+/-16.2 micromol/L, t=2.820, P=0.02<0.05, 82.2+/-24.0 micromol/L, t=2.760, P=0.03<0.05, 74.2+/-21.9 micromol/L, t=2.822, P=0.02<0.05). Serum NOS activity at each time point had no significant difference between two groups. In experimental group, intestinal mucosal NOS activity at 1 h post-reperfusion reduced significantly when compared with pre-cold IR (0.79+/-0.04 U/mg vs 0.46+/-0.12 U/mg, t=3.460, P=0.009<0.01). Mucosal NOS activity at 24, 48, and 72 h post-reperfusion also reduced significantly when compared with pre-cold IR (0.79+/-0.04 U/mg vs 0.57+/-0.14 U/mg, t=2.380, P=0.04<0.05, 0.61+/-0.11 U/mg, t=2.309, P=0.04<0.05, 0.63+/-0.12 U/mg, t=2.307, P=0.04<0.05). In control group, mucosal NOS activity at 1 and 24 h post-reperfusion was significantly lower than that in pre-cold IR (0.72+/-0.12 U/mg vs 0.60+/-0.07 U/mg, t=2.320, P=0.04<0.05, 0.58+/-0.18 U/mg, t=2.310, P=0.04<0.05). When compared to the normal value, Na+-K+-ATPase activity increased significantly at 48 and 72 h post-reperfusion in experimental group (2.48+/-0.59 micromol/mg vs 3.89+/-1.43 micromol/mg, t=3.202, P=0.04<0.05, 3.96+/-0.86 micromol/mg, t=3.401, P=0.009<0.01) and control group (2.48+/-0.59 micromol/mg vs 3.58+/-0.76 micromol/mg, t=2.489, P=0.04<0.05, 3.67+/-0.81 micromol/mg, t=2.542, P=0.03<0.05). This novel technique for intestinal autotransplantation provides a potentially consistent and practical model for experimental studies of graft cold preservation. L-arginine supplementation during cold IR may act as a useful adjunct to preserve the grafted intestine.

Treatment of gastric hemorrhage by pulverized omeprazole and antacid – concomitant administration via a nasogastric tube

Gastroesophageal reflux (GER) is a common episode in pediatric patients with severe motor and intellectual disabilities (SMID) and occasionally leads to a severe clinical state accompanied with nausea, hematemesis, melena, wheezing, pneumonia, anemia and/or failure to thrive. We report here a case of a 14-year-old male with Lennox syndrome who had been treated with a histamine H2 blocker intravenously or via a nasogastric tube for repeated gastric hemorrhage due to severe GER. Since his gastric hemorrhage became resistant to the H2 blocker, we decided to replace it with a proton pump inhibitor (PPI). Although lansoprazole can be decapsulated for administration via a nasogastric tube, it tends to block fine tubes. The acid-sensitive drug omeprazole, another oral PPI, is commercially available as enteric-coated tablets. Therefore, we pulverized the tablets and administered omeprazole, mixed with a small amount of antacid, via a nasogastric tube. The patient's gastric hemorrhage was dramatically improved. Thus, administration of pulverized omeprazole concomitantly with antacid via a fine nasogastric tube may provide a novel approach for the treatment of chronic GER in pediatric patients with SMID.

Synthesis of amorphous calcium phosphates for hard tissue repair using conventional melting technique

The technical use of phosphate glasses has been restricted because of their strong hygroscopic nature. Traditionally phosphate glasses have been used as an opaline in silicate glasses since the solubility of phosphate in silicate glasses at lower temperature is very poor. Their poor chemical durability can be improved by the introduction of higher valency elements such as Ba, Al, or Be. The most important property of the phosphate glass is its ability to dissolve some elements and oxides that are insoluble or poorly soluble in glasses of other materials and crystalline compounds. Another important use of phosphate glasses is their application as biomaterials based on the calcium phosphate system. Their similarities in composition to bone and teeth make them ideal candidates. The first proposed application of the calcium phosphate glass to the biomaterials was proposed as dental restorative materials such as the crown because of their excellent castability as well as sufficient mechanical strength [1, 2]. The purpose of this study was to explore calcium phosphate glasses having an amorphous structure as potential biomaterials in hard tissue repair. We synthesized amorphous calcium phosphate glasses by melting and subsequent quenching process. Batches in the system CaO–CaF2–P2O5–MgO–ZnO were prepared with six kinds of Ca/P ratios from 0.2 to 1.2 using CaCO3, CaF2, H3PO4, MgO, and ZnO as raw materials. The molar ratio of CaO/CaF2 was fixed to 9. MgO and ZnO were added at 1 wt%, respectively. Mixed batches were dried at 80 ◦C and melted at temperatures ranging from 800 to 1550 ◦C depending on the Ca/P ratios. They were subsequently quenched onto the graphite plate at room temperature after melting. In order to determine the crystallinity and crystalline phases of the as-quenched samples, X-ray diffraction analysis was performed using Philips APD 3720 X-ray diffraction apparatus with a fine focus copper target X-ray tube. As shown in Fig. 1, there was no crystalline peak up to Ca/P of 0.6. When Ca/P ratio was 0.8, the sample exhibited the Zn3(PO4)2 as well as Ca2P2O7; the former had disappeared but the latter still remained. Ca2P2O7 phase partially transformed to Ca4P2O7 with increasing Ca/P to 1.2. Crystallinity Figure 1 XRD patterns of the as-quenched samples. • and denote Ca2P2O7 and Zn3(PO4)2, respectively.

Retinal microvascular surgery: a feasibility study.

To evaluate the feasibility of microvascular surgery at the level of the retinal vasculature. Porcine eyes were used, and eyecups were prepared under an operating microscope. Several classic microvascular maneuvers were explored, such as vascular puncturing, catheterization, mobilization, intravascular injections, and various combinations of the same. Instruments used ranged from disposable 30-gauge needles to an Er:YAG laser. Commercially available 10-0 nylon sutures, fine polyimide tubes, and custom-made fine glass tubes were used for vascular catheterization. Puncturing, mobilization, catheterization, and intravascular injection of retinal arteries and veins were possible. The connection of two remote retinal vessels with a fine tube was also achieved with the combination of these maneuvers. The feasibility of performing several microvascular maneuvers on retinal arteries and veins was demonstrated in porcine eyes. Further experimentation and development of these findings in a living animal model could lead to the development of such microvascular maneuvers in humans.

Bimodal distribution of fasting gastric acidity in a rural African population.

The people of Transkei eat a diet high in linoleic acid, the principal fatty acid in maize. The theory has been put forward that a diet high in linoleic acid and low in fat and riboflavin, such as the traditional diet in Transkei, results in overproduction of prostaglandin E2 in the gastric mucosa, and that this overproduction in turn causes a suppression of gastric acid production. To investigate the effect of diet on fasting gastric pH in a rural black African population. Fasting gastric acid samples were obtained by fine nasogastric tube aspiration from 150 volunteers at a rural health clinic. The pH of these samples was measured and a full dietary questionnaire was used. Helicobacter pylori serology was done on a subgroup of 30 volunteers. A bimodal pH distribution was found. Approximately half the population had a gastric pH within the range 1-4. Half had a pH of over 4. A high pH was significantly associated with consumption of maize (p = 0.006), and with consumption of both pumpkin and beans (p = 0.006). A high proportion of this rural African population has a diet-associated abnormally high gastric pH. The pattern of upper gastrointestinal disease may be significantly affected by diet in this community and in others with a similar diet.

Ac nanocalorimeter for measuring heat capacity of biological macromolecules in solution

A precise calorimeter has been developed to measure the heat capacity of a small amount of liquid using a novel ac calorimetric method in which the effect of heat loss from a sample cell is corrected using the phase of the ac temperature. The sample cell is made of a fine glass tube, whose outer surface is plated with a nickel film as an ac heater. The ac temperature of the sample is detected precisely with a microbead thermistor attached to the middle of the tube. The resistance of the thermistor is measured with an ac Wheatstone bridge which is composed of resistors with a low temperature coefficient of ±1 ppm/K. The unbalance ac signal of the bridge is measured with a lock-in amplifier. To reduce the drift of measured values caused by the variation of room temperature, the amplifier and measuring instruments with temperature coefficients of &amp;gt;1 ppm/K are kept at constant temperature. Moreover, the gain of the amplifier is calibrated at every measuring point. Consequently, the heat capacity of 10 μl liquid can be determined with an extremely high sensitivity of ±0.001%, which corresponds to heat capacity changes of ±300 nJ/K. A test of the performance was made of the heat capacity measurement during thermal denaturation of lysozyme dissolved in buffered solution. This method is particularly useful for studying thermal properties of biological macromolecules in solution, since the heat capacity of macromolecules can be measured with a 10 μg sample.

Quantum-well microtube constructed from a freestanding thin quantum-well layer

We fabricated and experimentally investigated a nanostructure known as a quantum-well (QW) microtube, which is a fine tube with a micron- or nanometer-order diameter fabricated by rolling a semiconductor GaAs QW. Although the wall thickness is only 40 nm, the system retains the quantum properties of a QW, and photoluminescence from the QW subband can be clearly observed. Even though the QW width is sufficiently small to make the QW subband type-II band-aligned, a type-II to type-I transition caused by uniaxial strain in the microtube allows for optical emission.

Preabsorption of a polyclonal antibody raised against a peptide-keyhole limpet haemocyanin conjugate to allow analysis of molluscan protein

Keyhole limpet (Megathura crenulata) haemocyanin (KLH) is widely used in immunobiology, primarily because it is an extremely potent antigen. 1 One of the main uses of KLH is as a hapten carrier for production of polyclonal antibodies. For small, relatively nonimmunogenic target molecules, a better immune response can be elicited by conjugating these molecules to KLH. A potential disadvantage with this strategy is that polyclonal antibodies raised in this manner will not only contain antibodies against the target molecule, but will also contain antibodies against KLH. Therefore the use of antibodies raised against a hapten conjugated to KLH is restricted to situations where detection of the hapten will not be compromised by the presence of proteins to which antibodies specific to KLH moieties will also bind. We encountered this problem during an investigation into the regulation of protein synthesis in the common brown garden snail Helix aspersa. As part of this investigation we wished to analyse H. aspersa proteins by Western analysis with an antibody specific to the phosphorylated form of eukaryotic initiation factor 2� [anti-eIF2� (P) Research Genetics Inc.]. This polyclonal antibody was raised in New Zealand white rabbits against a phosphorylated 13 amino acid peptide obtained from rat eIF2� and conjugated to KLH. The phosphorylated residue is serine, and corresponds to serine51 in human eIF2� . eIF2� is a highly conserved protein in eukaryotes and the region around the regulatory phosphorylation site is completely conserved across eukaryotes. 2,3 Therefore it would be expected that this antibody could be used to detect phosphorylated eIF2� derived from any eukaryote. The manufacturers report that the serum containing the antibodies is purified by using the ‘free’ (not bound to KLH) immunizing peptide in an affinity purification step to remove non-eIF2� antibodies. Subsequently the antibody is affinity purified against the non-phosphorylated form of the protein (Research Genetics Inc. Product Data Sheet for anti-eIF2� ). However, given that the vast majority of antibodies produced will be KLH specific, even a very low level of residual contamination could manifest as confounding anti-KLH activity. While the antibody shows good specificity to eIF2� (P) in mammalian extracts we have found that there is an extremely high level of non-eIF2� (P) binding when applied to H. aspersa extracts. We report here a simple method by which non-specific antibodies raised against a KLH-hapten complex can be removed by preabsorption with H. aspersa haemolymph. Helix aspersa were collected from the grounds of the University of Western Australia and surrounding suburban gardens. Haemolymph for preabsorption of the anti-eIF2� (P) antibody was freshly prepared and removed from H. aspersa individuals by first removing a small section of the shell (the ventral side of the second largest whorl) to expose a region of the mantle directly over the pericardium. A very fine capillary tube (prepared by heating and elongating a pasteur pipette) was inserted directly into the heart and haemolymph was extracted by capillary action. To ensure that the haemolymph was cell-free, it was centrifuged at 10,000 g for 20 min at room temperature and the supernatant was removed. The anti-eIF2� (P) antibody was preabsorbed by adding it to the cell-free haemolymph (1 � l of antibody solution to 100 � l of haemolymph) and incubating the mixture at room temperature for 2 h. After preabsorption, the antibody (in haemolymph) was diluted in TBST (20 mM Tris-HCl pH 7.5, 500 mM sodium chloride, 0.05% (v/v) Tween-20) containing 1% non-fat milk to give the appropriate dilution. Tissues sectioned from H. aspersa were homogenized in 9 volumes of 1� assay/lysis buffer using an Ultra-Turrax T25 homogenizer (Janke and Kunkel IKA Labortechnik) at 20500 rpm for 30 sec on ice. 1� assay buffer consisted of 120 mM potassium

Dynamics of plasma Ca and calcitonin levels in stonefish (Inimicus japonicus) administered a high-Ca solution into the stomach.

In stonefish, changes in plasma total Ca and calcitonin levels were examined after administration of a high-Ca solution into the stomach. Blood was taken successively at 0, 1, 3, 9, 33, and 81 hr from a fine tube cannulated into the aortic bulb. Plasma Ca levels increased acutely at 1 hr and attained the peak after 3-9 hr of the administration. Although plasma calcitonin levels did not exhibit conspicuous changes for 1-3 hr, they began to rise significantly at 33 hr. The plasma Ca level began to decline significantly at 33 hr, although the level was still significantly higher than the initial level. At 33 hr, however, the plasma calcitonin level still continued to increase. At 81 hr, the plasma Ca level had returned to the initial level. At that time, the plasma calcitonin level was also significantly lower than that at 33 hr. These results suggest that, in stonefish, the ultimobranchial gland has the ability to respond physiologically to rises in plasma Ca levels, to secrete calcitonin, and to cease the secretion when the plasma Ca levels return to the initial level.

Selective Fetal Hypophysectomy in utero: Microsurgical Technique and Comparisons with Hypophysectomy by Decapitation

A detailed description is given of a surgical technique for selectively removing the pituitary anlage from the intrauterine fetal rat as an alternative to the more generally applied fetal hypophysectomy by decapitation. Fetuses on the 17th day of gestation were approached through a narrow opening in the uterine wall and fetal membranes. The pituitary gland was sucked out with a fine glass tube introduced from the side of the head into the space between the pons and the ventral hypothalamus, where the gland is situated. The female rat was sacrificed on the 22nd day of gestation (the day before delivery) and the surviving fetuses were preserved. On average, 20% of the operated fetuses survived until that day, 20% of which were completely hypophysectomized (microscopical examination). Operated fetuses with intact pituitaries served as surgical controls for the evaluation of selected effects of the total hypophysectomy. Initial comparisons were made with published results based on hypophysectomy by decapitation, evaluated without access to surgical controls. The two methods of fetal pituitary removal provide consistent results as regards the weight increase of adrenal and thyroid glands (retardation), thymus gland (stimulation) and testicles (no effect). On the other hand, body weight increase was not affected by selective hypophysectomy but instead slowed down after decapitation, whereas the growth in length of the humerus bone was stimulated and retarded, respectively.

Metal fingers on grain boundaries in multicrystalline silicon solar cells

AbstractWe have developed a method of applying a net‐like finger grid to the front of multicrystalline (mc) silicon solar cells, which lies mainly on the grain boundaries (grain‐boundary‐oriented‐finger GBOF grid). This net has no busbars. It is drawn by a plotter, using screen printing paste dispensed through a fine tube. The power output of cells contacted in this manner has been tested in a statistical study of pairs and triplets of cells of size 100 × 100 mm2 (Bayer) and 103 × 103 mm2 (Eurosolare). In the pairs study, pairs of neighbouring wafers of the original ingot were processed into solar cells. One wafer received a GBOF grid, the other got the same grid rotated by 90°, and so had little coverage of grain boundaries. In the study of triplets the third wafer of each triplet was equipped with a standard H‐pattern of the same shading as the GBOF grid. In the pairs study, we find that under approximately standard conditions there is an 89% chance that the GBOF grid increases power output over cells with an identical, but 90° rotated, grid, the most probable increase being 2.6%. The triplets study shows that there is an 87% chance that the GBOF grid increases power output over cells with the standard H‐pattern, the most probable increase being 2.5%. Copyright © 2002 John Wiley &amp; Sons, Ltd.

Peroxisomal catalase in extrusion apparatus posterior vacuole of microsporidian spores.

A remarkable survival adaptation of microsporidians is the spore extrusion apparatus (EXA), which is equipped to explosively discharge a tube through which the infective sporoplasm is sent into a host cell. The EXA consists of a membrane-associated aperture, polaroplast, polar filament protein, and a posterior vacuole. When the spore activates, the EXA discharges a long, fine tube by an apparent eversion process. When the tube is fully formed, the sporoplasm moves down the tube and ends up in an enveloped compartment thought to be derived from the everted extrusion apparatus membrane. The energy source for spore discharge is believed to reside in the EXA posterior vacuole. In activated spores, the posterior vacuole swells before and during spore extrusion. We report here the presence of catalase in the posterior vacuole of the spores of a microsporidian, Spraguea lophii. This was first made evident when significant levels of molecular oxygen were detected in a medium containing the discharging spores. Clarkstyle oxygen microelectrodes (Model 7376C, Diamond General, Ann Arbor, Michigan) were used to measure dissolved oxygen in the medium. The oxygen appeared only when low levels of hydrogen peroxide were added to the medium, either before or during spore discharge. In the absence of hydrogen peroxide, no oxygen formed in the medium containing the firing spores. The medium was recovered from the fired spores and was analyzed for catalase enzyme using western blot analysis and using the protocol described earlier (1). The results indicate that catalase was present in the medium, and that the molecular weight corresponded to control catalase (Fig. 1A). This finding supports the old hypothesis that the EXA contents may be released directly into the surrounding medium during tube eversion. Catalase crystals were successfully isolated using the protocol described by Reinlein (2). The catalase-rich medium was placed in 10% NaCl, containing 2 mM KH2PO4 at pH 5.5, and after 1 h, this was dialyzed against 1 mM ammonium chloride (pH 5.5). To recrystalize the catalase, there were two cycles of 10-h dialysis. For clean crystals, the entire sample was recycled through the procedure a second time. The crystals tested positive for catalase on the basis of western blots with rabbit anti-bovine catalase (Rockland Immunochemicals, Gilbertsville, Pennsylvania). To identify the specific location of the catalase, spores of S. lophii were subjected to the alkaline-diaminobenzidine (DAB) procedure as reported by Novikoff and Goldfischer (3). The DAB reaction localized to the posterior vacuole before and during spore activation (Fig. 1B). After spore discharge, no detectable DAB activity was found in either the spore ghosts or the extruded sporoplasms. Although the mechanism by which catalase works in the posterior vacuole is unclear, it may be associated with the oxidation of long chain fatty acids. Docosahexaenoic acid, commonly associated with peroxisomes, is significantly represented in S. lophii spores (4). A function of peroxisomes is to manage the betaoxidation of long chain fatty acids. Acyl-coA oxidase, an essential enzyme in this process, produces hydrogen peroxide. The catalase in the area can convert the hydrogen peroxide to water and oxygen. The rapid oxidation of the long chain fatty acids may effect the swelling of the posterior vacuole and induce spore discharge.