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61.
Fukushima M Funabiki I Hashizume T Osada K Yoshida W Ishida S 《Zoological science》2008,25(7):760-765
It was reported recently that vertebrate-type steroids exist and control reproduction in several groups of invertebrates, including molluscs. Sexually reproductive freshwater planarians of the species Bdellocephala brunnea have a limited breeding season in their natural habitat. This phenomenon suggests that some endogenous reproductive hormones might play a role in vivo. However, to date, sex steroids such as androgen, estrogen, and progesterone have not been found in planarians. The goal of the present study was to determine whether androgen is present in sexual planarians such as B. brunnea. The presence of testosterone was detected by high-pressure liquid chromatography and, in sexually reproductive individuals in which no seminal vesicles were visible, the level of testosterone was about twice than that in individuals with visible seminal vesicles. An enzyme-linked immunosorbent assay revealed that the levels of testosterone during terminal spermatogenesis were three times higher than during the spermatocyte-building phase. Our results indicate that sexually reproductive freshwater planarians such as B. brunnea might have vertebrate-type steroids and show variation in testosterone levels during spermatogenesis. 相似文献
62.
Sasaki M Takahashi K Haneda Y Satoh H Sasaki A Narumi A Satoh T Kakuchi T Kaga H 《Carbohydrate research》2008,343(5):848-854
An aqueous solution of glucose was reacted at temperatures from 200 to 400 degrees C under atmospheric pressure using a continuous flow reactor. For reaction temperatures above 300 degrees C, the liquid product yield was not sensitive to the temperature change; on the other hand, below 300 degrees C, it decreased rapidly with decreasing temperature. 1,6-Anhydro-beta-D-glucopyranose (AGP) and 1,6-anhydro-beta-D-glucofuranose (AGF) were the major components in the liquid product. The yields of AGP and AGF were 40% and 19%, respectively, at 360 degrees C and a feed rate of 0.5 mL/min. The optimum space time to produce AGP and AGF was about 0.2-0.4s under the present temperature conditions. 相似文献
63.
64.
Spectrally silent conformation change after photoexcitation of photosynthetic reaction centers isolated from Rhodobacter sphaeroides R-26 was observed by the optical heterodyne transient grating technique. The signal showed spectrally silent structural change in photosynthetic reaction centers followed by the primary P+BPh- charge separation and this change remains even after the charge recombination. Without bound quinone to the RC, the conformation change relaxes with about 28micros lifetime. The presence of quinone at the primary quinone (QA) site may suppress this conformation change. However, a weak relaxation with 30-40micros lifetime is still observed under the presence of QA, which increases up to 40micros as a function of the occupancy of the secondary quinone (QB) site. 相似文献
65.
Mycorrhizal fungi were isolated from the nonphotosynthetic orchid Chamaegastrodia sikokiana and identified as members of Ceratobasidiaceae by phylogenetic analysis of the internal transcribed spacer (ITS) region of
ribosomal deoxyribonucleic acid. The ITS sequences were similar among geographically separated samples obtained from Mt. Kiyosumi
in Chiba Prefecture and Mt. Yokokura in Kochi Prefecture. One of the isolated fungi, KI1-2, formed ectomycorrhiza on seedlings
of Abies firma in pot culture, suggesting that tripartite symbiosis exists among C. sikokiana, mycorrhizal fungi, and A. firma in nature, and carbon compounds are supplied from A. firma to C. sikokiana through the hyphae of the mycorrhizal fungi. To our knowledge, this is the second study to suggest the involvement of Ceratobasidiaceae
fungi in tripartite symbiosis with achlorophyllous orchids and photosynthetic host plants. 相似文献
66.
A community of arbuscular mycorrhizal (AM) fungi was investigated in a warm-temperate deciduous broad-leaved forest using
a molecular analysis method. Root samples were obtained from the forest, and DNA was extracted from the samples. Partial 18S
rDNA of AM fungi were amplified from the extracted DNA by polymerase chain reaction using a universal eukaryotic primer NS31
and an AM fungal-specific primer AM1. After cloning the PCR products, 394 clones were obtained in total, which were divided
into five types by restriction fragment length polymorphism (RFLP) with HinfI, RsaI, and Hsp92II. More than 20% of the clones were randomly selected from each RFLP type and sequenced. Phylogenetic analysis showed that
all the obtained clones belonged to Glomus but could not be identified at species level. Topsoil of the forest containing plant roots was inoculated to nonmycorrhizal
seedlings of indigenous woody plants, Rhus javanica var. roxburghii and Clethra barvinervis, to introduce the community of AM fungi into the seedlings. Among these five RFLP types, four types were detected from both
seedlings, which indicates that the AM fungal community in the forest root samples was introduced at least partly into the
seedlings. Meanwhile, an additional four types that were not found in the forest root samples were newly detected in the seedlings,
these types were closely related to one another and close to G. fasciculatum or G. intraradices. It is expected that a community of indigenous diverse AM fungi could be introduced into target fields by planting these
mycorrhizal seedlings. 相似文献
67.
Toshitsugu Kawata Kaoru Tenjou Chiyoko Tokimasa Tadashi Fujita Masato Kaku Akira Matsuki Shinya Kohno Keisuke Tsutsui Junji Ohtani Masahide Motokawa Mao Shigekawa Yuiko Tohma Kazuo Tanne 《Experimental Animals》2004,53(1):47-51
Alendronate, one of the bisphosphonates, is known to have an inhibitory effect on bone resorption. The purpose of this study was to investigate the effects of alendronate on ectopic bone graft resorption and to determine the optimal dose in the mouse. The grafted bone in the control group disappeared due to resorption by osteoclasts within 5 weeks. In the experimental groups, the area of bone tissue decreased by only 20-40% at 5 weeks post-operatively. At 8 and 9 weeks after surgery, the decreased area of bone structure was significantly less in all the 10(-4) M injected alendronate-immersed groups than in the 10(-4) M non-injected alendronate-immersed. At 9 weeks after surgery, the number of osteoclasts were significantly less in the 10(-4) M injected alendronate-treated groups than in the 10(-4) M non-injected alendronate-treated groups. These results suggest that alendronate inhibits resorption of ectopic bone graft at concentrations of 10(-4) and 10(-6) M. 相似文献
68.
Shunpei Sato Hiroyuki Kojima Junko Ando Hironori Ando Richard L. Wilmot Lisa W. Seeb Vladimir Efremov Larry LeClair Wally Buchholz Deuk-Hee Jin Shigehiko Urawa Masahide Kaeriyama Akihisa Urano Syuiti Abe 《Environmental Biology of Fishes》2004,69(1-4):37-50
We examined the genetic population structure of chum salmon, Oncorhynchus keta, in the Pacific Rim using mitochondrial (mt) DNA analysis. Nucleotide sequence analysis of about 500 bp in the variable portion of the 5′ end of the mtDNA control region revealed 20 variable nucleotide sites, which defined 30 haplotypes of three genealogical clades (A, B, and C), in more than 2,100 individuals of 48 populations from Japan (16), Korea (1), Russia (10), and North America (21 from Alaska, British Columbia, and Washington). The observed haplotypes were mostly associated with geographic regions, in that clade A and C haplotypes characterized Asian populations and clade B haplotypes distinguished North American populations. The haplotype diversity was highest in the Japanese populations, suggesting a greater genetic variation in the populations of Japan than those of Russia and North America. The analysis of molecular variance and contingency χ2 tests demonstrated strong structuring among the three geographic groups of populations and weak to moderate structuring within Japanese and North American populations. These results suggest that the observed geographic pattern might be influenced primarily by historic expansions or colonizations and secondarily by low or restricted gene flow between local groups within regions. In addition to the analysis of population structure, mtDNA data may be useful for constructing a baseline for stock identification of mixed populations of high seas chum salmon. 相似文献
69.
Takehara M Ino K Takakusagi Y Oshikane H Nureki O Ebina T Mizukami F Sakaguchi K 《Analytical biochemistry》2008,373(2):322-329
Two kinds of layer silicate powder, Micromica and chlorite, were used to aid protein crystallization by the addition to hanging drops. Using appropriate crystallization buffers, Micromica powder facilitated crystal growth speed for most proteins tested in this study. Furthermore, the addition of Micromica powder to hanging drops allowed the successful crystallization of lysozyme, catalase, concanavalin A, and trypsin even at low protein concentrations and under buffer conditions that otherwise would not generate protein crystals. Except for threonine synthase and apoferritin, the presence of chlorite delayed crystallization but induced the formation of large crystals. X-ray analysis of thaumatin crystals generated by our novel procedure gave better quality data than did that of crystals obtained by a conventional hanging drop method. Our results suggest that the speed of crystal growth and the quality of the corresponding X-ray data may be inversely related, at least for the formation of thaumatin crystals. The effect of Micromica and chlorite powders and the application of layer silicate powder for protein crystallization are discussed. 相似文献
70.
Kazumi Yagasaki Naoko Morisaki Yoshiro Kitahara Atsuhito Miura Ryuhei Funabiki 《Cytotechnology》2003,43(1-3):97-103
Effects of leucine and related compounds on protein synthesis were studied in L6 myotubes. The incorporation of [3H]tyrosine into cellular protein was measured as an index of protein synthesis. In leucine-depleted L6 myotubes, leucine and its keto acid, α-ketoisocaproic acid (KIC), stimulated protein synthesis, while D-leucine did not. Mepacrine, an inhibitor of both phospholipases A2 and C, canceled stimulatory actions of L-leucine and KIC on protein synthesis. Neither indomethacin, an inhibitor of cyclooxygenase, nor caffeic acid, an inhibitor of lipoxygenase, diminished their stimulatory actions, suggesting no involvement of arachidonic acid metabolism. Conversely, 1-O-hexadecyl-2-O-methylglycerol, an inhibitor of proteinkinase C, significantly canceled the stimulatory actions of L-leucine and KIC on protein synthesis, suggesting an involvement of phosphatidylinositol degradation and activation of protein kinase C. L-Leucine caused a rapid activation of protein kinase C in both cytosol and membrane fractions of the cells. These results strongly suggest that both L-leucine and KIC stimulate protein synthesis in L6 myotubes through activation of phospholipase C and protein kinase C. 相似文献