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101.
MASAHIKO NAKAMURA 《Ibis》1995,137(4):477-483
The spacing system of Alpine Accentors Prunella collaris was studied on the summit of Mt. Norikura in central Japan for five breeding seasons. This species lived in groups (mean 7.2 individuals), sharing large areas of their individual home ranges within which all activities occurred. Membership of a group was closed and stable within a breeding season. The group home ranges overlapped little with each other, and antagonistic behaviour, including communal defence, was observed at the boundaries. Each female established an exclusive area around her own nest which she defended against other females (but not males) within the shared home range, but her activities (feeding, singing and mating) were observed over the whole of the group home range. Members of the same group moved around and fed together within the home range during the prebreeding season, but individual birds tended to become more solitary as the breeding season progressed. These results suggest that the primary breeding unit of Alpine Accentors is a group consisting of five to ten members who share a group territory which contains all the resources necessary for living and breeding, but this species is not a typical social one in which all members move around together within their group territory. 相似文献
102.
NAGASHIMA HIDEYUKI; NAKAMURA SAHEYE; NISIZAWA KAZUTOSI; HORI TERUZO 《Plant & cell physiology》1971,12(2):243-253
ADP-glucose: -l,4-glucan -4-glucosyltransferase was obtainedfrom a marine red alga Serraticardia maxima in a form boundwith floridean starch granules. The enzyme catalyzed the transferof glucosyl residue from ADP-glucose, UDP-glucose and GDP-glucoseto floridean starch added as a primer. ADP-glucose was the mostefficient glucosyl donor in the reaction. Maltose was producedby ß-amylolysis of the glucan synthesized by the algalenzyme. The optimum pH for enzyme activity was at 8.4. The enzymewas not obtained in a soluble form from either the chloroplastextract or the whole algal cell extract. Electron micrographsof algal cells revealed that floridean starch granules are localizedexclusively outside chloroplasts. Hence, it appears that mostof the synthetase is present outside chloroplasts.
1 Contribution from the Shimoda Marine Biological Station, TokyoKyoiku University, No. 202. This work was supported by a Grant-in-Aidfor Cooperative Research from the Ministry of Education, Japan.
2 Present address: Department of Biology, Faculty of Science,Science University of Tokyo, Kagurazaka, Tokyo 162, Japan.
3 Present address: Laboratory of Biology, Faculty of Science,Toho University, Narashino, Chiba 275, Japan. (Received May 25, 1970; ) 相似文献
103.
EFFECT OF GIBBERELLIC ACID ON ELONGATION AND NUCLEIC ACID SYNTHESIS IN ETIOLATED ALASKA PEA EPICOTYL
TERUKO NAKAMURA YASUKO YABUUCHI NORIKO TAKAHASHI 《Development, growth & differentiation》1970,12(3):189-197
The following results were obtained using etiolated Alaska pea epicotyls. Gibberellic acid (GA) had the remarkable effect on the elongation in part I (elongating region) of epicotyls, whereas it had little effect on that in part II (mature region) of epicotyls. In cortex of part I and II of epicotyls, the cell number in longitudinal direction was hardly affected by GA. On the increase in width of epicotyls, GA was hardly effective in any parts of epicotyls. In both part I and II GA enhanced the incorporation of 32P into all nucleic acid fractions prepared by methylated albumin kieselguhr (MAK) columns, i.e. sRNA, DNA and rRNA + mRNA. In part I the net increase in DNA and RNA content during the incubation period was slightly promoted by GA, whereas in part II the net decrease in both nucleic acids content was slightly promoted by GA. The relationship between GA-induced growth and nucleic acid synthesis is discussed. 相似文献
104.
TZUHUA LIN JUKKA PAJARINEN YUSUKE KOHNO MASAHIRO MARUYAMA MONICA ROMERO-LOPEZ JHIH-FONG HUANG KARTHIK NATHAN TAHSIN N. KHAN ZHENYU YAO STUART B. GOODMAN 《Cytotherapy》2018,20(8):1028-1036
Background
Mesenchymal stromal cell (MSC)–based therapy has great potential to modulate chronic inflammation and enhance tissue regeneration. Crosstalk between MSC-lineage cells and polarized macrophages is critical for bone formation and remodeling in inflammatory bone diseases. However, the translational application of this interaction is limited by the short-term viability of MSCs after cell transplantation.Methods
Three types of genetically modified (GM) MSCs were created: (1) luciferase-expressing reporter MSCs; (2) MSCs that secrete interleukin (IL)-4 either constitutively; and (3) MSCs that secrete IL-4 as a response to nuclear factor kappa-light-chain-enhancer of activated B cell (NFκB) activation. Cells were injected into the murine distal femoral bone marrow cavity. MSC viability and bone formation were examined in vivo. Cytokine secretion was determined in a femoral explant organ culture model.Results
The reporter MSCs survived up to 4 weeks post-implantation. No difference in the number of viable cells was found between high (2.5?×?106) and low (0.5?×?106) cell-injected groups. Injection of 2.5?×?106 reporter MSCs increased local bone mineral density at 4 weeks post-implantation. Injection of 0.5?×?106 constitutive IL-4 or NFκB-sensing IL-4–secreting MSCs increased bone mineral density at 2 weeks post-implantation. In the femoral explant organ culture model, LPS treatment induced IL-4 secretion in the NFκB-sensing IL-4–secreting MSC group and IL-10 secretion in all the femur samples. No significant differences in tumor necrosis factor (TNF)α and IL-1β secretion were observed between the MSC-transplanted and control groups in the explant culture.Discussion
Transplanted GM MSCs demonstrated prolonged cell viability when transplanted to a compatible niche within the bone marrow cavity. GM IL-4–secreting MSCs may have great potential to enhance bone regeneration in disorders associated with chronic inflammation. 相似文献105.
MASAHISA NAKAMURA AKIKO FUJIWARA AKIRA SUZUKI SHOICHI OKINAGA KIYOSHI ARAI 《Development, growth & differentiation》1983,25(1):49-56
Glucose utilization by spermatids was found to be 17.37±0.37 nmoles/hr/106 cells at 34°C and 28.94±1.12nmoles/hr/106 cells at 40°C. A good parallelism was observed between the increased rate of glucose utilization and lactate production at 40°C. There was no significant change in the levels of glycolytic intermediates in the cells, except for marked accumulations of fructose-1, 6-diphosphate, dihydroxyacetone phosphate and glyceraldehyde-3-phosphate in the presence of glucose (1 mM). Glucose oxidation in the citrate cycle by spermatids was higher at 40°C than at 34°C, but was never greater than 2% of the overall rate of glucose utilization. In addition, glucose did not prevent decrease of ATP at either 34 or 40°C. The effects of temperature on the activities of 11 glycolytic enzymes were examined. The activities of aldolase and phosphoglyceromutase were similar between 30 and 34°C, but increased markedly at 40°C. The higher temperature increased the Vmax values, without affecting the Kms. The activities of other glycolytic enzymes were similar at the different temperatures. These findings indicate that the increased overall rate of glucose utilization in glycolysis at higher temperature is due to increased Vmax values of aldolase and phosphoglyceromutase. 相似文献
106.
MECHANICAL PROPERTIES OF THE CELL SURFACE IN STARFISH EGGS 总被引:2,自引:2,他引:0
The mechanical properties of the cell surface of the starfish egg at various stages of maturation have been investigated using the cell elastimeter. When constant negative pressure was applied to a part of the cell with a micropipette closely in contact with it, it bulged out, and the bulge rapidly increased at first and then gradually reached a steady value within one min. The relation between the deformation of the cell surface (i.e. degree of bulging) and applied negative pressure was almost linear in both oocytes at the germinal vesicle stage and mature eggs. The surface force and the elasticity value: i.e., the product of the elastic modulus of the surface membrane (layer) and its thickness, were determined from the relation between the deformation and the negative pressure. The elasticity value was about 5 times the surface force in both oocytes at the germinal vesicle stage and mature eggs. When maturation of the oocyte was induced by 1-methyladenine, the stiffness of the cell surface decreased shortly before the breakdown of the germinal vesicle. The stiffness transiently increased at the time of formation of the first and second polar-bodies. 相似文献
107.
EIKO WADA HISAKO SAKIYAMA MICHIO NAKAMURA SHIRO KANEGASAKI 《Cell biochemistry and function》1997,15(1):19-26
We have examined the pattern of protein myristoylation in C3H10T1/2 fibroblasts during cell growth. During the growing phase of 10T1/2 cells, several proteins were radiolabelled with [3H]myristate, and among them proteins with molecular masses of 22, 35, a doublet of 42–45 and 67 kDa were labelled predominantly. The extent of myristoylation in each of these proteins changed with cell density. The amount of radioactivity incorporated into the 22 kDa protein in 10T1/2 cells decreased with increasing cell density and remained at a low level during the stationary phase. In contrast, the incorporation into the 67 kDa protein increased parallel to cell density. The density-dependent change of myristoylation was not observed in any of the transformants of 10T1/2 cells thus far examined. The 67 kDa protein was identified as MARCKS (myristoylated alanine-rich C kinase substrate) by immunoprecipitation with an anti-MARCKS antibody. By Western blot analysis, we found that the amount of MARCKS in 10T1/2 cells increased significantly analogous with cell density. Therefore, it is possible that MARCKS and the 22 kDa protein play a role in contact-mediated cell signalling in 10T1/2 cells, but the mechanism is lost in transformed cells. © 1997 John Wiley & Sons, Ltd. 相似文献
108.
In order to elucidate the physiological mechanism of palmelloid formation of the unicellular green alga Chlamydomonas eugametos by chloroplatinic acid, the factors causing inhibition of the palmelloid formation were studied in various media. Chloroplatinic acid lost its palmelloid-forming effect in the presence of nitrite ion and amines having a second functional group. Nitrate, potassium, and sodium ions and monofunctional amines were without influence on the effect of chloroplatinic acid. These results indicate that the active form of platinum (IV) may undergo ligand substitution, the resulting complex being unable to cause palmelloid formation. 相似文献
109.
ICHIRO NAKAMURA 《Systematic Entomology》1976,44(3):283-295
Two new species of lycaenid butterflies, Strymonidia jebelia and Pseudophilotes sinaicus, are described from the high mountains of South Sinai. The foodplants and the eggs of both species are also described with notes on the habitats and adult behaviour. Their relationships with closely allied species and the possible evolutionary histories are discussed. 相似文献
110.