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1.
Yamaguchi Haruo; Yamaguchi Mineo; Fukami Kimio; Adachi Masao; Nishijima Toshitaka 《Journal of plankton research》2005,27(6):603-606
Utilization of phosphate diester (PDE) and phosphodiesterase(PDEase) production by five marine phytoplankton species wereexamined in the laboratory to evaluate the contribution of PDEto the growth of phytoplankton. Among the five marine phytoplanktonspecies tested, only Chaetoceros ceratosporus was able to usethe PDE compound, bis(p-nitrophenyl) phosphate (bis-NPP), effectivelyas a sole phosphorus source. In addition, C. ceratosporus simultaneouslyproduced both PDEase and alkaline phosphatase (APase) at almostequal activity levels under the phosphate-deficient condition.These results suggest that PDE compounds presumably play animportant role as a phosphorus source for PDEase-producing phytoplanktonin coastal environments. 相似文献
2.
Obi Ichiro; Ichikawa Yoshiaki; Kakutani Tadaaki; Senda Mitsugi 《Plant & cell physiology》1989,30(3):439-444
Electrophoretic mobilities of plant protoplasts from varioussources were measured, as a function of the pH of the medium,by a micro-electrophoresis technique to characterize the protoplastsin terms of curves of zeta potential vs. protoplast surfacepH (pHs). The shape of the curves of zeta potential vs. pHscurves differed among preparations of protoplasts isolated fromvarious species and strains. The isoelectric points (pI) ofthe protoplasts measured in this study were between 3.0 and4.0. These differences among the protoplasts suggest that itmay be possible to develop an electrophoretic method for theselection of protoplasts. The shape of the curves of zeta potentialvs. pHs also indicated that carboxyl groups, as well as phosphategroups, may contribute to the negative charges on the surfaceof protoplasts. (Received October 14, 1988; Accepted February 22, 1989) 相似文献
3.
K Oka J G Yuan M Senda A S Masibay P K Qasba H Masuno R O Scow J R Paterniti W V Brown P K Oasba 《Biochimica et biophysica acta》1989,1008(3):351-354
The expression of the gene for lipoprotein lipase (LPL) was studied in brown adipose tissue and the liver of combined lipase deficient (cld/cld) and unaffected mice. The mRNA specific for LPL was detected in both animals. Although the size of LPL mRNA in cld mice was similar to that of unaffected mice, the mRNA concentration in affected animals was higher than in unaffected animals. We also studied the LPL gene mutation in cld mice by Southern blot analysis. No restriction fragment length polymorphisms were observed after digestion with 16 endonucleases. These data indicate that there is no gene insertion or deletion, but do not exclude the possibility of point mutation in the LPL structural gene. However, the present results agree with the hypothesis that the genetic defect in cld is not due to a mutation in the LPL structural gene, but instead involves the defective post-translational processing of LPL or defective cellular function affecting transport and secretion of this enzyme group. 相似文献
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A novel IgA protease from Clostridium sp. capable of cleaving IgA1 and IgA2 A2m(1) but not IgA2 A2m(2) allotype paraproteins 总被引:6,自引:0,他引:6
Y Fujiyama K Kobayashi S Senda Y Benno T Bamba S Hosoda 《Journal of immunology (Baltimore, Md. : 1950)》1985,134(1):573-576
Three bacterial strains of Bifidobacterium and Clostridium sp. from patients with inflammatory bowel disease (I.B.D.) and Streptococcus pneumoniae from a patient with pneumonia were identified to produce extracellular proteases cleaving IgA into Fab and Fc fragments. Although the proteases from the Bifidobacterium and the Streptococcus pneumoniae showed the characteristics of typical IgA1 proteases, cleaving the IgA of only the IgA1 subclass, the protease from Clostridium sp. revealed a dual substrate specificity, in that it cleaved both IgA1 and IgA2 of the A2m(1) allotype. The latter protease, however, did not show any activity with respect to the IgA2 of the A2m(2) allotype. Fc fragments isolated from the IgA1 and the IgA2 A2m(1) by digestion with the Clostridium sp. protease were identified to have an identical amino terminal residue of valine. The site of cleavage in both the alpha 1 and the alpha 2 of A2m(1) by the protease was assumed to be an identical peptide bond at Pro(221)-Val(222), which is a common one present just before the hinge of both the alpha 1 and the alpha 2 of the A2m(1) but not of the alpha 2 of the A2m(2). The protease was sensitive to ethylene-diamino tetraacetic acid, a chelating agent, similar to other already reported IgA1 proteases. 相似文献
7.
Clostridium ramosum, an IgA protease-producing species and its ecology in the human intestinal tract 总被引:3,自引:0,他引:3
S Senda Y Fujiyama T Ushijima K Hodohara T Bamba S Hosoda K Kobayashi 《Microbiology and immunology》1985,29(11):1019-1028
A bacterial strain isolated from feces of a patient with ulcerative colitis, which had been shown to produce a novel immunoglobulin A (IgA) protease (cleaving both the human IgA1 subclass and IgA2 subclass of A2m(1) allotype) extracellularly, was identified as Clostridium ramosum. By using a selective medium (propionate-rifampicin-gentamicin-colimycin-polymyxin medium) devised for C. ramosum, analysis of the population level of this organism was performed to determine its ecology in the human intestinal tract. C. ramosum was isolated in 20 of 25 fecal samples (80%) from patients with inflammatory bowel disease (I.B.D.) and in 112 of 135 samples (83%) from patients without I.B.D. (control group). C. ramosum was also isolated from 6 of 11 biopsy samples (55%) of the inflamed rectal mucosa from patients with ulcerative colitis and from five of 15 samples (33%) from the intact mucosa of the control group. The population levels of C. ramosum in most of the biopsy samples ranged from 2.3 to 5.0 log10 per gram. The IgA protease-positive C. ramosum was found in only four of 135 fecal samples (3%) and one of 15 biopsy samples (6.7%) from the control group. These results indicate that IgA protease-positive C. ramosum is not likely to play a role in the induction of I.B.D., unless the organism is first isolated from the patient with I.B.D. 相似文献
8.
Takeda Junko; Abe Shunnosuke; Morikawa Hiromichi; Senda Mitsugi 《Plant & cell physiology》1983,24(4):667-676
The electrophysiological properties of the membrane of Nicotianatabacum var. Sarnsun cultured cells were determined using amicroelectrode technique in standard medium containing 1 mMKC1, 1 mM NaCl and 1 mu CaCl2 at pH 7. Tobacco callus was derivedfrom the pith (Em=104.4%16.2 mV). The membrane potentialsof the callus cells did not show a symmetrical Gaussian distributionbut were scattered over a wide range. The percentage of highmembrane potential cells increased as the subculture was continueduntil about 11 months and then decreased. The response of themembrane potential to electric stimulus, ionic composition,metabolic inhibitors, sugars and amino acids was characteristicof high (Em={small tilde}160 220 mV; H-cells)and low (Em=80{small tilde}90 mV; L-cells) membranepotential cells. The membrane potential of H-cells was largelydepolarized by addition of CN, carbonium cyanide m-chlorophenylhydrazone,decyclohexylcarbodiimide, and triphenyltin chloride and transientlydepolarized by addition of glucose, galactose, mannose or sucrose,and D-alanine, L-alanine or Llysine, but the membrane potentialof L-cells was not. (Received December 3, 1982; Accepted March 16, 1983) 相似文献
9.
Hideaki Kabuto Isao Yokoi Mineo Takei Tadashi Kurimoto Akitane Mori 《Neurochemical research》1994,19(4):463-467
Serotonin (5-HT) plays an important role in the seizures of El mice since the seizure threshold of El mice correlates with the 5-HT concentration in the central nervous system. In this study, the anticonvulsant effect of a 5-HT reuptake blocker, citalopram, was evaluated behaviorally and biochemically. El mouse convulsions were inhibited by oral administration of citalopram for 2 weeks. Citalopram increased tryptophan and tyrosine amounts, and decreased the 5-HT, 5-hydroxy-indoleacetic acid, kynurenine, and dopamine amounts in the brain. These findings show that citalopram depresses monoaminergic metabolism. Given the known convulsant effect of kynurenine, it is suggested that its decrease by citalopram may involve attenuation of El mice seizures. 相似文献
10.
Abstract: We have determined that synaptic vesicles contain a vesicle-specific keratan sulfate integral membrane proteoglycan. This is a major proteoglycan in electric organ synaptic vesicles. It exists in two forms on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, i.e., the L form, which migrates like a protein with an Mr of 100, 000, and the H form, with a lower mobility that migrates with an Mr of ∼250, 000. Both forms contain SV2, an epitope located on the cytoplasmic side of the vesicle membrane. In addition to electric organ, we have analyzed the SV2 proteoglycan in vesicle fractions from two other sources, electric fish brain and rat brain. Both the H and L forms of SV2 are present in these vesicles and all are keratan sulfate proteoglycans. Unlike previously studied synaptic vesicle proteins, this proteoglycan contains a marker specific for a single group of neurons. This marker is an antigenically unique keratan sulfate side chain that is specific for the cells innervating the electric organ; it is not found on the synaptic vesicle keratan sulfate proteoglycan in other neurons of the electric fish brain. 相似文献