Analysis of rice <Emphasis Type="Italic">RNA-dependent RNA polymerase 1</Emphasis> (<Emphasis Type="Italic">OsRDR1</Emphasis>) in virus-mediated RNA silencing after particle bombardment     

Hui Chen  Atsushi Tamai  Masashi Mori  Masashi Ugaki  Yoshikazu Tanaka  Partha P. Samadder  Akio Miyao  Hirohiko Hirochika  Naoto Yamaoka  Masamichi Nishiguchi 《Journal of General Plant Pathology》2010,76(2):152-160

RNA-dependent RNA polymerases (RDRs) play a key role in various RNA silencing pathways in many organisms. Using the nucleotide sequence of SGS2/SDE1/RDR6 in Arabidopsis as the search query for sequences that flank the insertions of rice retrotransposon Tos17, we selected rice mutant lines (OsRDR1). RT-PCR analysis showed that OsRDR1 mRNA was undetectable in leaves and calli of the mutants, while it was detected in wild type. RNA silencing was induced by particle bombardment to investigate any effects of OsRDR1 on RNA silencing with β-glucuronidase or green fluorescent protein DNA/RNA in the mutant lines. The results showed that RNA silencing was impaired in these mutant lines by inverted repeat (IR) DNA or in vitro transcribed double-stranded RNA. Further, the mutant lines were bombarded with Brome mosaic bromovirus (BMV, a ssRNA virus) or Wheat dwarf geminivirus (WDV, a ssDNA virus), each carrying the IR sequence of a reporter gene. As a result, RNA silencing was impaired by BMV. Interestingly, however, it was not impaired by WDV. Thus we propose that OsRDR1 is required for RNA silencing mediated by Bromovirus, but not by Geminivirus in this system.  相似文献   

Inflexibility of vertebral number in chum salmon <Emphasis Type="Italic">Oncorhynchus keta</Emphasis>     

Daisei Ando  Kazutaka Shimoda  Yoshihito Shinriki  Hirokazu Urabe  Tomoya Aoyama  Masamichi Nakajima 《Fisheries Science》2010,76(5):761-767

Chum salmon Oncorhynchus keta eggs from the Chitose and Shiriuchi rivers in Hokkaido, northern Japan, were incubated under identical conditions with the aim of comparing vertebral number (V _N) to that reported archived data from the 1950s. The comparison revealed that mean V _N of salmon from the Shiriuchi River has remained unchanged for 50 years and is higher than that from the Chitose River. The V _N in the Chitose River salmon was found to be significantly higher than that recorded in the archival data. The variation in the mean V _N of chum salmon fry collected during different seasons and years in the Chitose River falls within a range that has remained constant, suggesting that the difference between the values obtained in our study and the archival data may be due to differences in the timing of egg collection. These results indicate that the mean V _N of chum salmon has been stable for a long period. Incubation experiments under identical conditions are a useful tool for examining changes in genetic structure and detecting the essential properties of populations.  相似文献   

Nitrogen promotes water consumption in seedlings of Cryptomeria japonica but not in Chamaecyparis obtusa     

Junko Nagakura  Shinji Kaneko  Masamichi Takahashi  Takeshi Tange 《Forest Ecology and Management》2008

To evaluate the influence of excessive N deposition on the water consumption of a Japanese plantation forest, 1-year-old seedlings of major plantation trees, Cryptomeria japonica (Japanese cedar) and Chamaecyparis obtusa (Hinoki cypress), were treated with combinations of two N levels (Moderate N and High N) and two soil water conditions (Dry and Moist) for 4 months. The High N treatment received five times as much N as in the Moderate N treatment; the total amount of N added in the High N treatment was roughly 25 times the annual N deposition in precipitation. An increase in soil N availability increased the needle transpiration rate, needle biomass, and needle N content of C. japonica under the Moist treatment, whereas those of C. obtusa were not significantly affected by soil N treatment at either soil water level. Needle N content in C. japonica was positively related to needle photosynthetic rate and transpiration rate. Our results suggested that excessive N deposition has the potential to enhance water consumption in C. japonica stands on moist soils. However, the effects of increased N deposition would be insignificant for C. japonica grown on dry sites. Unlike in C. japonica, water consumption in C. obtusa would be unlikely to respond to excess N deposition, regardless of the soil moisture level. Moreover, the significant reduction in the fine root to needle ratio observed with excessive N application in C. japonica under both Dry and Moist treatments suggests that excessive N deposition is likely to cancel out the tree's morphological adaptation to drought.  相似文献   

Immunohistochemical survey of the gut endocrine cells in the common tree shrew (Tupaia belangeri).     

J Yamada  M Tauchi  W Rerkamnuaychoke  H Endo  N Chungsamarnyart  J Kimura  M Kurohmaru  E Hondo  N Kitamura  T Nishida  Y Hayashi 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》1999,61(7):761-767

Regional distribution and relative frequency of endocrine cells in the gastrointestinal tract of the common tree shrew (Tupaia belangeri) were studied immunohistochemically. Ten types of immunoreactive endocrine cells were localized in the gastric mucosa, i.e., chromogranin-, serotonin-, gastrin-, somatostatin-, bovine pancreatic polypeptide (BPP)-, enteroglucagon-, pancreatic glucagon-, peptide tyrosine tyrosine (PYY)-, motilin-, and substance P (SP)-immunoreactive (IR) cells. In the intestine, 13 types of immunoreactive cells were observed, i.e., chromogranin-, serotonin-, somatostatin-, gastrin-, BPP-, enteroglucagon-, PYY-, secretin-, cholecystokinin (CCK)-, gastric inhibitory peptide (GIP)-, motilin-, neurotensin-, and SP-IR cells. The regional distribution and relative frequency of the cell types varied along the gastrointestinal tract. Basically, the types, distribution, and relative frequency of the gut endocrine cells were similar to those reported in other mammalian species. However, some characteristic findings were noted in the present study: (1) the considerably large number of gastrin-IR cells in the pyloric region; (2) numerous serotonin-IR cells in the stomach; (3) appreciable number of BPP-IR cells in the transitional region of the stomach; and (4) wide distribution of PYY- and motilin-IR cells in the gut.  相似文献   

Cloning and studies of the mouse cDNA encoding Smad3.     

K Kano  A Notani  S Y Nam  M Fujisawa  M Kurohmaru  Y Hayashi 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》1999,61(3):213-219

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Estimation of heritability and genetic correlation of number of abdominal and caudal vertebrae in masu salmon     

Daisei Ando  Shu-Ichi Mano  Nobuhisa Koide  Masamichi Nakajima 《Fisheries Science》2008,74(2):293-298

ABSTRACT:   Ten sibship masu salmon Oncorhynchus masou masou families were produced to estimate the heritability of the number of abdominal vertebrae (AV) and caudal vertebrae (CV), and the genetic correlation between the two traits were calculated. The AV and CV of both the parents and their offspring were counted separately, and the heritability was estimated by performing parent–offspring regression analysis. The mean vertebral number of the offspring differed among families although they were reared under identical water temperature conditions and had the same parental vertebral number type in crossbreeding. The heritabilities were estimated as 0.65 for AV and 0.84 for CV. The genetic correlation between the number of AV and CV was calculated as −0.92. These results suggest that AV and CV are governed by genetic components even when the fish are reared under identical environmental conditions, and the total vertebral number is expected to converge within a certain range. It is necessary to analyze separately the variations in the number of AV and CV when investigating the vertebral number in masu salmon.  相似文献   

Fine-root dynamics in a young hinoki cypress (<Emphasis Type="Italic">Chamaecyparis obtusa</Emphasis>) stand for 3 years following thinning     

Kyotaro Noguchi  Qingmin Han  Masatake G. Araki  Tatsuro Kawasaki  Shinji Kaneko  Masamichi Takahashi  Yukihiro Chiba 《Journal of Forest Research》2011,16(4):284-291

Fine roots play a key role in carbon and nutrient dynamics in forested ecosystems. Fine-root dynamics can be significantly affected by forest management practices such as thinning, but research on this topic is limited. This study examined dynamics of fine roots <1 mm in diameter in a 10-year-old stand of hinoki cypress (Chamaecyparis obtusa) for 3 years following thinning (65% in basal area). Fine-root production and mortality rates were estimated using a minirhizotron technique in combination with soil coring. In both thinned and un-thinned control plots, fine-root elongation occurred from early spring to winter (March to December) and fluctuated seasonally. In the thinned and the control plots, the annual fine-root production rates were estimated to be 101 and 120 g m⁻² year⁻¹, respectively, whereas the estimated annual fine-root mortality rates were 77 and 69 g m⁻² year⁻¹, respectively. At 3 years after thinning, live fine-root biomass was significantly smaller in the thinned plot (143 g m⁻²) than in the control plot (218 g m⁻²), whereas dead fine-root biomass was not (147 and 103 g m⁻², respectively). Morphological and physiological indices of fine roots such as diameter, specific root length, and root tissue density of the live fine roots was similar in both plots. These results suggested that thinning tended to decrease biomass and production of fine roots, but the effects on characteristics of fine roots would be less evident.  相似文献   

Distribution of actin filaments in the seminiferous epithelium of the Habu,Trimeresurus flavoviridis     

Masamichi Kurohmaru  Toshiyasu Matsui  Hitomi Igarashi  Shosaku Hattori  Yoshihiro Hayashi 《Anatomia, histologia, embryologia》2019,48(5):505-507

The distribution of actin filaments was examined in the seminiferous epithelium of the Habu (Trimeresurus flavoviridis; snake), by transmission electron microscopy and fluorescence histochemistry. By transmission electron microscopy, actin filaments were clearly found only at the site between Sertoli cell and spermatid without a lattice‐like structure. Fluorescence histochemistry showed a weak labelling of actin filaments in the seminiferous epithelium, whereas these findings seem to be common among reptiles, they are different from those in mammals. Additionally, the bundles of actin filaments adjacent to the plasma membrane of Sertoli cells, appeared in other reptiles, were not observed in the Habu.  相似文献   

Effects of simulated drought stress on the fine roots of Japanese cedar (<Emphasis Type="Italic">Cryptomeria japonica</Emphasis>) in a plantation forest on the Kanto Plain,eastern Japan     

Bohdan Konôpka  Kyotaro Noguchi  Tadashi Sakata  Masamichi Takahashi  Zuzana Konôpková 《Journal of Forest Research》2007,12(2):143-151

Drought stress was simulated in a 28-year-old Japanese cedar plantation (Kanto Plain, Japan) between April and October 2004 by removing throughfall using rain shelters. Changes in fine-root parameters caused by this drought treatment were examined by sequential soil coring. Drought effects on fine roots were analyzed separately for particular soil depths (0–5, 5–15, and 15–25 cm) and root diameters (<1 and 1–2 mm). Generally, fine-root biomass and root tip numbers decreased by the drought treatment. Drought stress was most intense for fine roots in the topsoil and weakest for fine roots in the deepest soil layer. Fine roots less than 1 mm in diameter were affected more severely than 1- to 2-mm roots. The effect of drought treatment was most remarkable for the number of white root tips, which decreased to 17% of the control at the soil depth of 0–5 cm. These results suggest that white root tip is the most suitable indicator of drought stress. Simulated drought reduced production of fine roots less than 1 mm and 1–2 mm in diameter. Fine-root mortality was stimulated for roots less than 1 mm, but not for 1- to 2-mm roots. These results suggest that fine roots with larger diameters can survive drought stress at a level simulated in this study, but processes of fine-root production were inhibited regardless of the diameter classes. The duration of drought stress and phenology of fine roots should also be considered in diagnosing the effects of drought on fine-root parameters.  相似文献   

Growth and transpiration of Japanese cedar (Cryptomeria japonica) and Hinoki cypress (Chamaecyparis obtusa) seedlings in response to soil water content   总被引：1，自引：0，他引：1  

Nagakura J  Shigenaga H  Akama A  Takahashi M 《Tree physiology》2004,24(11):1203-1208

To investigate the effects of soil water content on growth and transpiration of Japanese cedar (Cryptomeria japonica D. Don) and Hinoki cypress (Chamaecyparis obtusa (Siebold et Zucc.) Endl.), potted seedlings were grown in well-watered soil (wet treatment) or in drying soil (dry treatment) for 12 weeks. Seedlings in the wet treatment were watered once every 2 or 3 days, whereas seedlings in the dry treatment were watered when soil water content (Theta; m3 m(-3)) reached 0.30, equivalent to a soil matric potential of -0.06 MPa. From Weeks 7 to 12 after the onset of the treatments, seedling transpiration was measured by weighing the potted seedlings. After the last watering, changes in transpiration rate during soil drying were monitored intensely. The dry treatment restricted aboveground growth but increased biomass allocation to the roots in both species, resulting in no significant treatment difference in whole-plant biomass production. The species showed similar responses in relative growth rate (RGR), net assimilation rate (NAR) and shoot mass ratio (SMR) to the dry treatment. Although NAR did not change significantly in either C. japonica or C. obtusa as the soil dried, the two species responded differently to the dry treatment in terms of mean transpiration rate (E) and water-use efficiency (WUE), which are parameters that relate to NAR. In the dry treatment, both E and WUE of C. japonica were stable, whereas in C. obtusa, E decreased and WUE increased (E and WUE counterbalanced to maintain a constant NAR). Transpiration rates were lower in C. obtusa seedlings than in C. japonica seedlings, even in well-watered conditions. During soil drying, the transpiration rate decreased after Theta reached about 0.38 (-0.003 MPa) in C. obtusa and 0.32 (-0.028 MPa) in C. japonica. We conclude that C. obtusa has more water-saving characteristics than C. japonica, particularly when water supply is limited.  相似文献