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21.
Shiro Tsuyuzaki 《Journal of plant research》1989,102(4):511-520
Soon after the 1977–78 eruptions of the volcano Usu, there were created many gullies in which former topsoil, i.e., well-developed
soil accumulated before the eruptions, was eroded in the crater basin, whereas the outside of the gully was covered with thick
volcanic deposits. The short-dispersal-seed plants were the most abundant in the inside of gully where the former topsoil
was exposed, however, they have not immigrated from external environments. The germination tests of the seeds extracted from
the former topsoil demonstrated that viable seeds were buried at 1683.3/m2 for 9 years after the eruptions. At least, 12 herbaceous species, e.g.,Rumex obtusifolius, Geum macrophyllum var.sachalinense andPoa annua, were derived from the buried seeds in the former topsoil. Their contribution to revegetation was estimated to be 40.0% in
the inside of gully where the former topsoil was exposed in 1983, suggesting that buried seeds are one of the most important
seed source for revegetation even in the case of a volcano which produced pumice and ash by eruption. 相似文献
22.
23.
T Sato N Tanaka S Neya N Funasaki T Iizuka Y Shiro 《Biochimica et biophysica acta》1992,1121(1-2):1-7
Examination was made of CO binding reactions to four kinds of modified sperm whale myoglobin (Mb), whose heme was reconstituted by iron complexes of synthetic porphyrins such as porphine (Por), meso-tetramethylporphyrin (TMeP), meso-tetraethylporphyrin (TEtP) and meso-tetra(n-propyl)porphyrin (TnPrP), using flash photolysis and stopped-flow methods. The CO association rate was found to be 5- to 20-times and dissociation rate 10- to 36-times accelerated by replacement with synthetic hemes. These features could be explained based on characteristic structures of modified Mbs indicated by X-ray crystallography. The side chain of Arg-45 protruded from the heme vicinity into the solvent region and heme was tilted by interactions of meso-alkyl side chains with surrounding peptides, resulting in the formation of widely opened channels and pockets for ligand passage. These structural features indicate the CO ligand to more easily enter or exit from heme pockets of reconstituted myoglobins, compared to native Mb. 相似文献
24.
Shinji Takai Nariaki Fukunaga Kei Kamisawa Yumiko Imai Yukako Sasaki Shiro Tsubaki 《Microbiology and immunology》1996,40(8):591-594
We recently reported that there are two different virulence-associated antigens correlated with virulence levels in Rhodococcus equi isolates from AIDS patients: virulent R. equi that kills mice with 106 cells expresses 15- to 17-kDa antigens and intermediately virulent R. equi that kills mice with 107 cells expresses a 20-kDa antigen. Environmental parameters were evaluated for their effects on the expression of these virulence-associated antigens in virulent R. equi strains by immunoblotting using monoclonal antibodies in this study. Expression of these two virulence-associated antigens of R. equi was regulated by pH and temperature; the antigens were produced maximally when the isolates were grown at 38 C and pH 6.5, but were not produced when grown at 38 C and pH 8, nor at temperatures below 30 C. The 20-kDa antigen was found to be located on the cell surface, as were the 15- to 17-kDa antigens, and showed susceptibility to proteolysis by trypsin. These results indicate that expression of the virulence-associated antigens of R. equi is dependent on the environmental conditions. 相似文献
25.
Norio Ohashi Yoko Koyama Hiroshi Urakami Masahiro Fukuhara Akira Tamura Fumihiko Kawamori Seigo Yamamoto Shiro Kasuya Kentaro Yoshimura 《Microbiology and immunology》1996,40(9):627-638
A total of 40 strains of Orientia tsutsugamushi (34 isolates from patients and trombiculid mites in Japan, and 6 prototype strains of antigenic variants) were examined for classification based on the reactivities with type-specific monoclonal antibodies in indirect immunofluorescence tests, and on the restriction fragment length polymorphism of a polymerase chain reaction (PCR)-amplified 56-kilodalton type-specific antigenic protein gene. By these methods, several antigenic and genotypic variants were found among the strains, and these variants were classified into types and further into subtypes. These results suggest that there are many variants in O. tsutsugamushi, and the methods used here seem to be useful for the systematic classification of the numerous variants. A strain which may be a new type distinguishable from those identified previously was also found in this study. Furthermore, variety in the degree of pathogenicity in mice related to type and/or subtype classification were observed. 相似文献
26.
The human S1-5 gene (fibrillin-like; FBNL) was originally isolated from a subtractively enriched cDNA library established from a subject with Werner syndrome (WS). We isolated genomic clones containing the entire S1-5 gene and determined its genomic structure including the exon–intron organization. The gene spanned approximately 18 kb of genomic DNA and consisted of 12 exons. Its expression was abundant in all tissues examined except brain and peripheral leukocytes, where it was undetectable. In addition, we have mapped S1-5 by fluorescencein situhybridization to chromosome 2p16, a position that excludes it as a candidate for WS. Our data should facilitate an understanding of the function and regulation of S1-5 in human tissues. 相似文献
27.
28.
Summary Using an ethanol solution of nile blue, we have developed an efficient method to detect the colonies of poly(3-hydroxyalkanoic
acids) (PHA) producing bacteria on the agar plate. When the bacterial colonies with PHA granules were stained with nile blue,
the stained colonies fluoresced bright orange on the irradiation of UV light. In the fluoresce emission spectra, fluorescence
intensity increased with an increase in the PHA content of bacterial cells.Alcaligenes eutrophus andA.latus colonies with poly(3-hydroxybutyric acid) (PHB) homopolymer exhibited an emission maximum at 580nm on the excitation at 490nm.
On the other hand,Pseudomonas oleovorans andP.putida with medium-chain-length (mcl-) PHA copolymers of C6, C8 and C10 units exhibited an emission maximum at 570nm. 相似文献
29.
Tomonari Tsutsumi Tetsuyuki Kobayashi Hiroshi Ueda Emiko Yamauchi Shiro Watanabe Harumi Okuyama 《Neurochemical research》1994,19(4):399-406
A membrane preparation from rat brain catalyzed the hydrolysis of [2-3H]glycerol-labeled lysophosphatidylinositol (lysoPI) to yield monoacylglycerol (MG) and inositolphosphates. This phospholipase C activity had an optimal pH of 8.2. The membrane preparation did not require the addition of Ca2+ for its maximum activity, but the activity was inhibited by addition of 0.1 mM EDTA to the assay mixture and was restored by simultaneous addition of 0.2 mM Ca2+. The activity was found to be localized in synaptic plasma membranes prepared by Ficoll and Percoll density gradients. The phospholipase C was highly specific for lysoPI; diacylglycerol formation from phosphatidylinositol, and MG formation from lysophosphatidylcholine, lysophosphatidylethanolamine, and lysophosphatidylserine were below 5% of that observed with lysoPI under the conditions used. We concluded that there is a pathway for phosphatidylinositol metabolism in brain synaptic membranes which is different from the well-characterized phosphoinositide-specific phospholipase C pathway.Abbreviations PI
phosphatidylinositol
- lysoPI
lysophosphatidylinositol
- lysoPI-PLC
lysophosphoinositide-specific phospholipase C
- PI-PLC
phosphoinositide-specific phospholipase C
- MG
monoacylglycerol
- PLC
phospholipase C
To whom to address reprint requests. 相似文献
30.
Connections among species-abundance (i-m
i
), species-frequency (i-F
i
), and species-sample size (S
n
-n) relationships were examined on the basis of the mapping data of a natural forest in Thailand. The spatial distribution of
individual trees without any discrimination of species was nearly random. Provided that the spatial distribution of each species
was random, thei-m
i
and thei-F
i
relationship was reconstructed from each other in terms of the total number of species (S) and the total number of individuals (N) in the data. The number of species (S
n
) in a subsample consisting ofn individuals was then obtained from thei-F
i
relationship. Logarithm ofS
n
increased with logn and showed a convex curve through the origin. The values of diversity indices based onN andS(orn andS
n
) were affected by sample size. These trends were further examined on the basis of 944 data sets of biotic communities and
three mathematical models of anS-N relationship. The properties of species-area relation were discussed in the light of these results. 相似文献