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71.
Pongphen Jitareerat Hiroyuki Matsumoto Masahiro Umehara Shinji Tsuyumu 《Journal of General Plant Pathology》2003,69(1):49-54
Erwinia chrysanthemi (Ech) triggers soft rot disease mainly by secreting pectate lyase (Pel), which is regulated in a complex manner by many regulatory
genes. In a previous study, we used a gene dosage method to show that the ddl gene, which encodes d-alanine-D-alanine ligase, reduced Pel production and tissue maceration by Ech strain EC16n. In this study, the ddl
− marker-exchanged mutant was shown to overcome the long growth lag caused by various salts in the growth medium and to increase
Pel production over that by EC16n, especially in a medium containing magnesium salts. Thus, ddl seems to regulate Pel production in a negative manner. Because the profiles of a gel shift assay using the pelE promoter region as the target DNA with crude extracts of EC16n and ddl
− mutant were distinguishable, Ddl is thought to affect the binding of other regulatory proteins. Expression of the ddl gene was induced in the medium containing a low-molecular-weight fraction of potato extract, but it was reduced in that containing
both polygalacturonic acid (PGA) and the fraction. The repression of ddl expression by PGA should contribute in part to the in planta hyperinduction of Pel.
Received: May 15, 2002 / Accepted: June 20, 2002 相似文献
72.
73.
Larvae of jack mackerel Trachurus japonicus were sampled in seven depth layers (0–10 m, 10–20 m, 20–30 m, 30–40 m, 40–50 m, 50–70 m, and 70–100 m), with a closing-type
frame net, on 26th–27th February, 2003, at Sta. V (27°50′N, 126°00′E) continental shelf edge in the southern part of East
China Sea, to examine their vertical distribution. Most of the larvae (>90%) occurred in the upper 50 m layer during both
day and night. In the daytime, larvae of length from 3.0 mm to 4.5 mm were most abundant in the 10–20 m layer, those from
5.0 to 6.0 mm were most abundant in the 20–30 m layer, those from 6.0 to 8.0 mm occurred at greater depth, in the 30–40 m
layer, and those more than 9.0 mm were found in the 0–10 m layer and performed ontogenetic vertical migrations. Larvae from
6 mm to 8 mm length performed diurnal vertical migration, for the percentage (16.7%) of larval number in the 0–20 m layer
in the daytime increased to 42.1% at night and the percentage (78.1%) in the 20–50 m layer in the daytime decreased to 49.0%
at night. 相似文献
74.
Shinji Kajihara Junki Itou Noritoshi Katsutani Tanajuro Goto Hideo Shimaji 《Scientia Horticulturae》2009
The arching and high-rack culture systems were developed and patented by Japanese rose growers. Both culture systems have bent canopies (lower bent shoots). In the arching culture system, shoots sprouting from the crown are harvested as cut flowers. However, the high-rack culture system also has a bent canopy originating from the mother stem (upper bent shoots) and flower stems sprout and is harvested at the top of each mother stem. Partitioning of photosynthates originating from bent shoots in arching and high-rack culture systems of rose production was investigated to elucidate how carbohydrates are re-allocated from the bent shoots in different culture systems of roses. At the flowering stage in both culture systems, 50–70% of 13C-photosynthates originated from bent shoots were exported to other parts within 72 h after 13CO2 feeding to the bent shoot. In the arching culture system, photosynthates from lower bent shoots were partitioned mainly to the roots and crown. Similarly, in the high-rack culture system, between 71 and 86% of the exported carbon from the bent shoots were allocated to below the point of bending (roots + crown + mother stems) and only 9–28% was allocated to flowering shoots above the point of bending. In both culture systems, photosynthate translocation from the lower bent shoot directly to flowers was low. Accordingly, bent shoots in rose plants acted as a source of photosynthates, independent of culture system. The height of the bent shoots determined for a great deal in the re-allocation of the photosynthates, and provides a partial explanation for difference in production of cut roses. 相似文献
75.
76.
Sharifah Rahmah Keitaro Kato Shinji Yamamoto Kenji Takii Osamu Murata Shigeharu Senoo 《Aquaculture Research》2014,45(12):2000-2009
Manipulation of stocking densities (10, 20, 30, 40 and 50 larvae L?1), each with or without the presence of shelter was conducted to determine the effects on survival, cannibalism and growth performances of larval bagrid catfish Mystus nemurus (Valenciennes 1840) from 2 to 14 days after hatching. This study revealed that stocking density significantly affected survival, cannibalism, total length, feed intake, specific growth rate and final weight of bagrid catfish larvae. Significantly higher survival was observed at moderate stocking density of more than 20 but less than 50 larvae L?1. Survival was significantly low beyond this threshold and was the lowest at 10 larvae L?1, coincides with the highest cannibalism. Total length, feed intake, specific growth rate and final weight were significantly higher at 10 larvae L?1. Shelter significantly improved total length and feed intake. No significant effects of stocking density and shelter were observed on the apparent feed conversion ratio and coefficient of variation. There was also no significant interaction between stocking density and shelter in all parameters. This study suggests that bagrid catfish larvae could be cultured at more than 20 but less than 50 larvae L?1 with the availability of shelter for optimal larviculture condition. 相似文献
77.
Taro Matsumoto Hiroshi Ihara Yoshinari Ishida Shinji Yamamoto Osamu Murata Yasunori Ishibashi 《Fish physiology and biochemistry》2010,36(1):63-70
Although chub mackerel (Scomber japonicus) is widely distributed all over the world, the relevance of its visual sensitivity to its ecology is not yet fully understood.
We investigated spectral sensitivity in juvenile chub mackerel in the range of ultraviolet (UV) to visible light (369–652 nm)
by electroretinogram (ERG) using light-emitting diodes (LEDs). Sensitivity peaked at a wavelength of approximately 482 nm
in dark-adapted fish and 525 nm in light-adapted fish. A secondary sensitivity peak in the UV range at approximately 382 nm
was found in both dark- and light-adapted fish. The UV sensitivity of chub mackerel may be attributable to UV transmissibility
of the optical media and to the presence of a beta-band of visible light-sensitive visual pigments, and not to an alpha-band
of UV visual pigments. This UV sensitivity may be useful for feeding or communication with other fishes. 相似文献
78.
Shin Ugawa Muneyoshi Yamaguchi Satoru Miura Shinji Kaneko 《Soil Science and Plant Nutrition》2013,59(4):510-516
Fine root biomass can be estimated from the quantity of DNA of a target plant extracted from fine root samples using regression analysis. However, the application of this method to fine root samples mixed with soil particles (mixed samples) is difficult due to the high DNA adsorption capacity of some clay minerals. Our aim in this study was to clarify the enhancement level of the DNA extraction efficiency of an improved method, and to obtain a regression line between the amount of DNA and the root biomass from a mixed sample with similar reliability as for fine roots alone (pure root sample). We examined the amount of DNA extracted from a mixture of Zea mays L. fine roots and highly adsorbent Kanuma soil using various concentrations of a skim milk solution, which acts as an adsorption competitor for the soil particles during the DNA extraction process. The amount of DNA of Zea mays extracted from the mixed sample using 0% skim milk was lower than from the pure root sample. However, the amount of DNA extracted from the mixed sample increased with increasing concentrations of skim milk, reaching the same level as for the pure root samples and resulting in a regression line that was similar to the pure root samples. Optimal DNA extraction levels were obtained with the addition of 20?µL of a 20% skim milk solution to 30?mg of a mixed sample. We also discuss the applicability of this method to other plant species and soil types. 相似文献
79.
Dickeya dadantii (syn. Erwinia chrysanthemi) is a causal agent of soft-rot diseases on many crops. Here, we characterized a gene belonging to the major facilitator superfamily
(MFS), which is involved in the symport, antiport, or uniport of various substrates, and the survival and virulence of many
Gram-negative bacterial animal pathogens, for the possible involvement in the plant pathogenicity of D. dadantii. A marker-exchange mutant of this gene (mfsX) was constructed that had decreased maceration ability in Chinese cabbage, potato, and chicory. Observation with electron
microscopy showed greatly reduced numbers of flagella per cell. This mutant had a significant reduction in swimming and swarming
motility and a severe reduction in formation of biofilm. Because these phenotypes have been shown to be involved in plant
pathogenicity of D. dadantii, mfsX seems to play an important role in pathogenesis of D. dadantii 3937 by its involvement in the expression of these pathogenicity-related phenotypes. 相似文献
80.
Minoru Tanaka Koji Tanina Shinji Kasuyama Tomio Usugi 《Journal of General Plant Pathology》2007,73(4):286-289
In October 2001, a disease of rocket larkspur (Cosolida ambigua (L.) P. W. Ball et Heyw), characterized by witches’ broom, yellows and virescence of flowers, was found in Yakage Town in
Okayama Prefecture. Electron microscopy revealed the presence of phytoplasma-like bodies in the phloem of diseased plants.
The causal phytoplasma was identified as “Candidatus Phytoplasma asteris” based on 16S rDNA sequence analysis, and demonstrated to be acquired by the leafhopper Macrosteles striifrons.
The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under the accession number AB258330. 相似文献