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61.
Hiroki Takagi Shintaro Sugawara Tomoka Saito Haruka Tasaki Lu Yuanxue Guan Kaiyun Dong-Sheng Han Toshinari Godo Masaru Nakano 《Plant biotechnology reports》2011,5(2):187-195
The gesneriaceous perennial plant Titanotrichum oldhamii has beautiful foliage and attractive bright yellow flowers. However, breeding of T. oldhamii by conventional sexual hybridization may be difficult because sexual reproduction of this species is very rare. In the present
study, plant regeneration systems via both direct and indirect formation of adventitious shoots from leaf explants were established
as the first step toward breeding T. oldhamii by using biotechnological techniques. Adventitious shoots were formed efficiently on medium containing 0.1 mg l−1 benzyladenine. Histological observation showed that shoot formation on this medium occurred directly from leaf epidermal
cells without callus formation. On the other hand, leaf explants formed calluses on medium containing 0.1 mg l−1 2,4-dichlorophenoxyacetic acid. The calluses could be maintained by monthly subculturing to fresh medium of the same composition.
When the calluses were transferred to plant growth regulator-free medium, they formed adventitious shoots. Directly and indirectly
formed shoots rooted well on medium containing 0.1 mg l−1 indole-3-butyric acid. Plantlets thus obtained were successfully acclimatized and grew vigorously in the greenhouse. Flow
cytometry analysis indicated that no variation in the ploidy level was observed in plants regenerated via direct shoot formation,
whereas chromosome doubling occurred in several plants regenerated via indirect shoot formation. Regenerated plants with the
same ploidy level as the mother plants showed almost the same phenotype as the mother plants, whereas chromosome-doubled plants
showed apparent morphological alterations: they had small and crispate flowers, and round and deep green leaves. 相似文献
62.
Nobuaki Matsumori Toshiyuki Yamaguchi Yoshiko Maeta Michio Murata 《Biophysical journal》2015,108(12):2816-2824
Sphingomyelin (SM) and cholesterol (Chol) are considered essential for the formation of lipid rafts; however, the types of molecular interactions involved in this process, such as intermolecular hydrogen bonding, are not well understood. Since, unlike other phospholipids, SM is characterized by the presence of an amide group, it is essential to determine the orientation of the amide and its order in the lipid bilayers to understand the nature of the hydrogen bonds in lipid rafts. For this study, 1′-13C-2-15N-labeled and 2′-13C-2-15N-labeled SMs were prepared, and the rotational-axis direction and order parameters of the SM amide in bilayers were determined based on 13C and 15N chemical-shift anisotropies and intramolecular 13C-15N dipole coupling constants. Results revealed that the amide orientation was minimally affected by Chol, whereas the order was enhanced significantly in its presence. Thus, Chol likely promotes the formation of an intermolecular hydrogen-bond network involving the SM amide without significantly changing its orientation, providing a higher order to the SM amide. To our knowledge, this study offers new insight into the significance of the SM amide orientation with regard to molecular recognition in lipid rafts, and therefore provides a deeper understanding of the mechanism of their formation. 相似文献
63.
Tomokazu Yasuda Hiroshi Tsuchikawa Michio Murata Nobuaki Matsumori 《Biophysical journal》2015,108(10):2502-2506
In this report, we applied site-specifically deuterated N-stearoylsphingomyelins (SSMs) to raft-exhibiting ternary mixtures containing SSM, 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), and cholesterol (Chol) and successfully acquired deuterium quadrupole coupling profiles of SSM from liquid-ordered (Lo) and liquid-disordered (Ld) domains. To our knowledge, this is the first report that shows detailed lipid chain dynamics separately and simultaneously obtained from coexisting Lo and Ld domains. We also found that the quadrupole profile of the Lo phase in the ternary system was almost identical to that in the SSM-Chol binary mixture, suggesting that the order profile of the binary system is essentially applicable to more complicated membrane systems in terms of the acyl chain order. We also demonstrated that 2H NMR spectroscopy, in combination with organic synthesis of deuterated components, could be used to reveal the accurate mole fractions of each component distributed in the Lo and Ld domains. As compared with the reported tie-line analysis of phase diagrams, the merit of our 2H NMR analysis is that the domain-specific compositional fractions are directly attainable without experimental complexity and ambiguity. The accurate compositional distributions as well as lipid order profiles in ternary mixtures are relevant to understanding the molecular mechanism of lipid raft formation. 相似文献
64.
65.
66.
Reinstatement of Grateloupia subpectinata (Rhodophyta, Halymeniaceae) based on morphology and rbcL sequences 总被引:1,自引:0,他引:1
Etienne Jean Faye Hong Wei Wang Shigeo Kawaguchi Satoshi Shimada Michio Masuda 《Phycological Research》2004,52(1):59-67
Morphological observations and molecular analyses of the north‐western Pacific species of the red algal genus Grateloupia (Halymeniaceae) indicate the presence of an entity, which is somewhat similar in gross morphology to G. asiatica Kawaguchi et Wang but is distinguished from the latter species by some morphological features. These include: (i) a somewhat fleshy texture; (ii) wider and much thicker (4.5–10 mm wide and up to 1300 μm thick) axes, of which an inner cortex consists of more (6–9) cells; (iii) generally longer (up to 17 cm), marginal and surface proliferations that are clearly constricted (terete) at bases; and (iv) much elongated, oblong auxiliary cells. Phylogenetic analysis using the ribulose‐l,5‐bisphosphate carboxylase/ oxygenase (rbcL) gene of G. asiatica and the alga in question shows them to be distantly related and strongly supports the differentiation of these two entities at the species level. Judging from the literature, this entity is actually Grateloupia subpectinata Holmes, which has been placed into synonymy under G. asiatica [as G. filicina (Lamouroux) C. Agardh] or G. prolongata J. Agardh in previous reports, and therefore the Holmes name is reinstated. 相似文献
67.
The nematocysts of Chiropsalmus
quadrigatus (Cubozoa; Cubomedusa; Chirodropidae) were examined to determine if their composition changes with an increase in body size.
Fixed tentacles of specimens collected in Okinawa, Japan, were homogenized and their nematocysts were observed under a differential
interference contrast microscope. Six nematocyst types were observed in medusae of all sizes microbasic mastigophores (MM),
large and small trirhopaloids (lTR and sTR), holotrichous isorhizas (HI), ellipsoidal isorhizas (eI), and ovoid isorhizas
(oI). Two other nematocysts, large ovoid isorhizas (loI) and microbasic euryteles (ME), were observed only in small individuals.
There was also marked difference in proportion of tentacular nematocysts between small and large individuals. HI was the dominant
type in small specimens, while MM and eI were predominant in large specimens. Nematocyst composition in the bell and pedalia
also differed between small and large individuals. Bells of small medusae contained oI and sTR, while only oI were observed
in most large individuals. The pedalia of small medusae had clusters of MM, ME, sTR, and oI. Such single clusters on pedalium
bases were characteristic of small individuals. The pedalia of large individuals contained scattered oI. Tentacles of medusae
are used for prey capture, so the changes in the major type of nematocysts in tentacles may reflect changes in prey type. 相似文献
68.
Takehiko Fukushima Kazuo Matsushige Noriko Takamura Michio Fukushima 《Hydrobiologia》2004,511(1-3):201-213
Quasi-continuous DO and pH measurements (total 47 days) were conducted during enclosure experiments (6 enclosures; 5 × 5 × 2.5 m), in which a biomass gradient of silver carp was created. After subtracting the air–water exchanges of O2 and CO2, the chemical and biochemical changes in DO (dissolved oxygen) and DIC (dissolved inorganic carbon) were estimated in order to evaluate MQ (metabolic quotient: DO change divided by DIC change) at intervals of 1 hour. By removing small absolute changes below the threshold value (0.01 mM h?1), the averaged values of the 24 MQ means for the respective 1-hour periods ranged from 0.96 to 1.20 in the six enclosures. Because the MQs in the daytime inversely correlated well with the ratio of NH+ 4–N to (NH+ 4–N + NO? 3–N), not the ecosystems, i.e., density of fish, community structure of zooplankton and phytoplankton, but the form of nitrogen uptaken for primary production principally determined the MQs. The higher MQs observed in the daytime compared with the nighttime (from 14% to 21% except 3% for one enclosure) could not be explained by the denitrification and/or dissolution of CaCO3 in the sediments, therefore suggesting the selectively faster decomposition of part of the organic matter provided through primary production, in other words, an accumulation of another part of the organic matter in the diurnal and/or daily time scale. 相似文献
69.
Nitrogen dynamics in the hyporheic zone of a forested stream during a small storm, Hokkaido, Japan 总被引:1,自引:0,他引:1
Hideaki Shibata Osamu Sugawara Hisano Toyoshima Steven M. Wondzell Futoshi Nakamura Tamao Kasahara Frederick J. Swanson Kaichiro Sasa 《Biogeochemistry》2004,69(1):83-104
Water and dissolved nitrogen flows through the hyporheic zone of a 3rd-order mountain stream in Hokkaido, northern Japan were measured during a small storm in August 1997. A network of wells was established to measure water table elevations and to collect water samples to analyze dissolved nitrogen concentrations. Hydraulic conductivity and the depth to bedrock were surveyed. We parameterized the groundwater flow model, MODFLOW, to quantify subsurface flows of both stream water and soil water through the hyporheic zone. MODFLOW simulations suggest that soil water inflow from the adjacent hill slope increased by 1.7-fold during a small storm. Dissolved organic nitrogen (DON) and ammonium (NH
4
+
) in soil water from the hill slope were the dominant nitrogen inputs to the riparian zone. DON was consumed via mineralization to NH
4
+
in the hyporheic zone. NH
4
+
was the dominant nitrogen species in the subsurface, and showed a net release during both base and storm flow. Nitrate appeared to be lost to denitrification or immobilized by microorganisms and/or vegetation in the riparian zone. Our results indicated that the riparian and hyporheic system was a net source of NH
4
+
to the stream. 相似文献
70.
Y. Fujii T. Fujiwara Y. Koide I. Hasan S. Sugawara S. Rajia S. M. A. Kawsar D. Yamamoto D. Araki R. A. Kanaly Y. Ogawa H. Fujita Y. Ozeki 《Glycoconjugate journal》2017,34(1):85-94
An N-acetyl sugar-binding lectin (termed iNoL) displaying cytotoxic activity against human cancer cells was isolated from the slipper lobster Ibacus novemdentatus (family Scyllaridae). iNoL recognized monosaccharides containing N-acetyl group, and glycoproteins (e.g., BSM) containing oligosaccharides with N-acetyl sugar. iNoL was composed of five subunits (330, 260, 200, 140, and 30 kDa), which in turn consisted of 70-, 40-, and 30-kDa polypeptides held together by disulfide bonds. Electron microscopic observations and gel permeation chromatography indicated that iNoL was a huge (500-kDa) molecule and had a polygonal structure under physiological conditions. iNoL displayed cytotoxic (apoptotic) effects against human cancer cell lines MCF7 and T47D (breast), HeLa (ovarian), and Caco2 (colonic), through incorporation (internalization) into cells. The lectin was transported into lysosomes via endosomes. Its cytotoxic effect and incorporation into cells were inhibited by the co-presence of N-acetyl-D-mannosamine (ManNAc). Treatment of HeLa cells with iNoL resulted in DNA fragmentation and chromatin condensation, through activation of caspase-9 and ?3. In summary, the novel crustacean lectin iNoL is incorporated into mammalian cancer cells through glycoconjugate interaction, and has cytotoxic (apoptotic) effects. 相似文献