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991.
992.
993.
Carrot embryogenic callus (EC) forms larger and tighter clusters of cells than does non-embryogenic callus (NC). Morphological
and histochemical analyses of EC and NC were made using the electron microscope. The entire cell wall in NC was strongly stained
by ruthenium red, which reacts primarily with carboxyl groups of acidic sugars. By contrast, in EC, strong staining by ruthenium
red of the entire cell wall, of amorphous structures on the surface of EC and of secretory vesicles was observed only after
treatment with NaOH. Scanning electron microscopy revealed the presence of amorphous structures on the entire surface of EC
but not of NC. These results suggest the abundance of non-methylesterified pectins and the presence of methylesterified and
peripherally located pectins in the cell walls of NC and EC, respectively, as well as the absence, in carrot cultured cells,
of any correlation between the calcium bridges of pectins and intercellular attachment.
Received: 28 April 1998 / Revision received: 20 September 1998 / Accepted: 27 October 1998 相似文献
994.
An aliquot of a water sample taken from an artificial pond on the campus of the Faculty of Science, Tokyo Metropolitan University, was filtered with Whatman GF/C glass fiber filters. Urea was added to the filtered and unfiltered waters, respectively to a final concentration of around 10 μg-at-N/l. These samples were kept in 10 liter glass bottles, which were kept on the surface of the pond with rope. Changes in the concentrations of urea, ammonium, nitrate, nitrite, and the number of bacteria were traced from 15 June through 13 July, 1973. The urea added to the unfiltered water decreased to about 1 μg-at-N/l within first three days. The decrement of the urea seemed to proceed as a first-order reaction with rate constant of 0.73 day−1. On the other hand, the urea added in the filtered water kept nearly the initial concentration for 18 days. As the number of bacteria in the filtered and unfiltered water were not significantly different, decrease of the urea in the unfiltered water may be ascribable to the participate fraction removed by the filtration. The urea was not decomposed by free bacteria. 相似文献
995.
Tomohito Mizuno Nobuhiko Satoh Shoko Horita Hiroyuki Tsukada Mayuko Takagi Yusuke Sato Haruki Kume Masaomi Nangaku Motonobu Nakamura 《The Journal of biological chemistry》2022,298(3)
Oxidized phospholipids have been shown to exhibit pleiotropic effects in numerous biological contexts. For example, 1-O-hexadecyl-2-azelaoyl-sn-glycero-3-phosphocholine (azPC), an oxidized phospholipid formed from alkyl phosphatidylcholines, is a peroxisome proliferator–activated receptor gamma (PPARγ) nuclear receptor agonist. Although it has been reported that PPARγ agonists including thiazolidinediones can induce plasma volume expansion by enhancing renal sodium and water retention, the role of azPC in renal transport functions is unknown. In the present study, we investigated the effect of azPC on renal proximal tubule (PT) transport using isolated PTs and kidney cortex tissues and also investigated the effect of azPC on renal sodium handling in vivo. We showed using a microperfusion technique that azPC rapidly stimulated Na+/HCO3− cotransporter 1 (NBCe1) and luminal Na+/H+ exchanger (NHE) activities in a dose-dependent manner at submicromolar concentrations in isolated PTs from rats and humans. The rapid effects (within a few minutes) suggest that azPC activates NBCe1 and NHE via nongenomic signaling. The stimulatory effects were completely blocked by specific PPARγ antagonist GW9662, ERK kinase inhibitor PD98059, and CD36 inhibitor sulfosuccinimidyl oleate. Treatment with an siRNA against PPAR gamma completely blocked the stimulation of both NBCe1 and NHE by azPC. Moreover, azPC induced ERK phosphorylation in rat and human kidney cortex tissues, which were completely suppressed by GW9662 and PD98059 treatments. These results suggest that azPC stimulates renal PT sodium-coupled bicarbonate transport via a CD36/PPARγ/mitogen-activated protein/ERK kinase/ERK pathway. We conclude that the stimulatory effects of azPC on PT transport may be partially involved in volume expansion. 相似文献
996.
Azumi K De Santis R De Tomaso A Rigoutsos I Yoshizaki F Pinto MR Marino R Shida K Ikeda M Ikeda M Arai M Inoue Y Shimizu T Satoh N Rokhsar DS Du Pasquier L Kasahara M Satake M Nonaka M 《Immunogenetics》2003,55(8):570-581
Genome-wide sequence analysis in the invertebrate chordate, Ciona intestinalis, has provided a comprehensive picture of immune-related genes in an organism that occupies a key phylogenetic position in vertebrate evolution. The pivotal genes for adaptive immunity, such as the major histocompatibility complex (MHC) class I and II genes, T-cell receptors, or dimeric immunoglobulin molecules, have not been identified in the Ciona genome. Many genes involved in innate immunity have been identified, including complement components, Toll-like receptors, and the genes involved in intracellular signal transduction of immune responses, and show both expansion and unexpected diversity in comparison with the vertebrates. In addition, a number of genes were identified which predicted integral membrane proteins with extracellular C-type lectin or immunoglobulin domains and intracellular immunoreceptor tyrosine-based inhibitory motifs (ITIMs) and immunoreceptor tyrosine-based activation motifs (ITAMs) (plus their associated signal transduction molecules), suggesting that activating and inhibitory receptors have an MHC-independent function and an early evolutionary origin. A crucial component of vertebrate adaptive immunity is somatic diversification, and the recombination activating genes (RAG) and activation-induced cytidine deaminase (AID) genes responsible for the Generation of diversity are not present in Ciona. However, there are key V regions, the essential feature of an immunoglobulin superfamily VC1-like core, and possible proto-MHC regions scattered throughout the genome waiting for Godot. 相似文献
997.
Yamahara T Shiono T Suzuki T Tanaka K Takio S Sato K Yamazaki S Satoh T 《The Journal of biological chemistry》1999,274(47):33274-33278
A novel extracellular Mn-superoxide dismutase (SOD) was isolated from a moss, Barbula unguiculata. The SOD was a glycoprotein; the apparent molecular mass of its native form was 120 kDa, as estimated by gel filtration chromatography, and that of its monomer was 22,072 Da, as estimated by time of flight mass spectroscopy. The protein had manganese with a stoichiometry of 0.80 Mn/monomer. The cDNA clone for a gene encoding the extracellular Mn-SOD was isolated. Sequence analysis showed that it has a strong similarity to germin (oxalate oxidase) and germin-like proteins (GLPs) of several plant species and possesses all the characteristic features of members of the germin family. The clone encoding this extracellular Mn-SOD was therefore designated B. unguiculata GLP (BuGLP). BuGLP had no oxalate oxidase activity. In addition, the cDNA for a gene encoding the moss mitochondrial Mn-SOD was isolated. Its amino acid sequence had little similarity to that of BuGLP, even though a close similarity was observed among the mitochondrial Mn-SODs of various organisms. BuGLP was the first germin-like protein that was really demonstrated to be a metalloprotein with Mn-SOD activity but no oxalate oxidase activity. 相似文献
998.
Shigechi H Koh J Fujita Y Matsumoto T Bito Y Ueda M Satoh E Fukuda H Kondo A 《Applied and environmental microbiology》2004,70(8):5037-5040
Direct and efficient production of ethanol by fermentation from raw corn starch was achieved by using the yeast Saccharomyces cerevisiae codisplaying Rhizopus oryzae glucoamylase and Streptococcus bovis alpha-amylase by using the C-terminal-half region of alpha-agglutinin and the flocculation functional domain of Flo1p as the respective anchor proteins. In 72-h fermentation, this strain produced 61.8 g of ethanol/liter, with 86.5% of theoretical yield from raw corn starch. 相似文献
999.
1000.
Rumi Kaida Yumi Satoh Vincent Bulone Yohko Yamada Tomomi Kaku Takahisa Hayashi Takako S. Kaneko 《Plant physiology》2009,150(4):1822-1830
Wall-bound purple acid phosphatases have been shown to be potentially involved in the regulation of plant cell growth. The aim of this work was to further investigate the function of one of these phosphatases in tobacco (Nicotiana tabacum), NtPAP12, using transgenic cells overexpressing the enzyme. The transgenic cells exhibited a higher level of phosphatase activity in their walls. The corresponding protoplasts regenerating a cell wall exhibited a higher rate of β-glucan synthesis and cellulose deposition was increased in the walls of the transgenic cells. A higher level of plasma membrane glucan synthase activities was also measured in detergent extracts of membrane fractions from the transgenic line, while no activation of Golgi-bound glycan synthases was detected. Enzymatic hydrolysis and methylation analysis were performed on the products synthesized in vitro by the plasma membrane enzymes from the wild-type and transgenic lines extracted with digitonin and incubated with radioactive UDP-glucose. The data showed that the glucans consisted of callose and cellulose and that the amount of each glucan synthesized by the enzyme preparation from the transgenic cells was significantly higher than in the case of the wild-type cells. The demonstration that callose and cellulose synthases are activated in cells overexpressing the wall-bound phosphatase NtPAP12 suggests a regulation of these carbohydrate synthases by a phosphorylation/dephosphorylation process, as well as a role of wall-bound phosphatases in the regulation of cell wall biosynthesis. 相似文献