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Chikaya Sakai Atok Subiakto Hani Sitti Nuroniah Naoto Kamata Koji Nakamura 《Journal of Forest Research》2002,7(2):73-80
We developed a vegetative propagation system for mass-producing three dipterocarps species,Shorea selanica Bl.,Shorea leprosula Mig., andShorea platyclados Sloot. This system uses fog evaporative cooling inside a greenhouse to reduce the leaf-to-air vapor pressure deficit (leaf-to-air
VPD) inside the propagator, even under high irradiance conditions. This cooling method has no negative influence on medium
conditions such as overwetting. A plastic tent propagator combined with this cooling method was used for vegetative propagation
experiments. In mass-production experiments, the annual rooting percentages from the cuttings were low in the first 2 years
(1997–1998) due to operational problems of the tent propagator (S. selanica, 48–51%;S. leprosula, 56–59%;S. platyclados: 50–63%). A hard cover propagator improved the rooting percentages in the mass-production experiments in 1999 because it
made operations easier (S. selanica, 70%;S. leprosula, 77%;S. platyclados, 77%). This system, which uses a combination of fog evaporative cooling and a hard plastic propagator, should be useful for
the mass propagation of these dipterocarp planting stocks.
This study was carried out under a joint project of the Ministry of Forestry, Indonesia and Komatsu Ltd. The project was supported
by Research Association for Reforestation of Tropical Forest (RETROF) organized by Japanese Forestry Agency. 相似文献
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Mst. Parvin MOSTARI Nahoko IEDA Chikaya DEURA Shiori MINABE Shunji YAMADA Yoshihisa UENOYAMA Kei-ichiro MAEDA Hiroko TSUKAMURA 《The Journal of reproduction and development》2013,59(3):266-272
Accumulating evidence suggests that the arcuate nucleus (ARC) kisspeptin/neurokinin B
(NKB)/dynorphin (KNDy) neurons play a role in estrogen negative feedback action on
pulsatile gonadotropin-releasing hormone (GnRH)/luteinizing hormone (LH) release. The
present study aimed to determine if dynorphin (Dyn) is involved in estrogen negative
feedback on pulsatile GnRH/LH release. The effect of the injection of nor-binaltorphimine
(nor-BNI), a kappa-opioid receptor (KOR) antagonist, into the third cerebroventricle (3V)
on LH pulses was determined in ovariectomized (OVX) adult female rats with/without
replacement of negative feedback levels of estradiol (low E2). The mean LH
concentrations and baseline levels of LH secretion in nor-BNI-injected, low
E2-treated rats were significantly higher compared with vehicle-treated
controls. On the other hand, the nor-BNI treatment failed to affect any LH pulse
parameters in OVX rats without low E2 treatment. These results suggest that Dyn
is involved in the estrogen negative feedback regulation of pulsatile GnRH/LH release. The
low E2 treatment had no significant effect on the numbers of ARC
Pdyn (Dyn gene)-,Kiss1- and
Tac2 (NKB gene)-expressing cells. The treatment also did not affect
mRNA levels of Pdyn and Oprk1 (KOR gene) in the
ARC-median eminence region, but significantly increased the ARC kisspeptin
immunoreactivity. These findings suggest that the negative feedback level of estrogen
suppresses kisspeptin release from the ARC KNDy neurons through an unknown mechanism
without affecting the Dyn and KOR expressions in the ARC. Taken together, the present
result suggests that Dyn-KOR signaling is a part of estrogen negative feedback action on
GnRH/LH pulses by reducing the kisspeptin release in female rats. 相似文献
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Chikaya Tanaka Yoshiaki Hashimoto Satoru Nakao Tatsuki Yoshinaga 《Fisheries Science》2009,75(1):191-194
To investigate the effect of oxidative stress on the survival of two Brachionus species of rotifer, we examined the effective dose of juglone, which generates reactive oxygen species, and compared survival
times between the two species. First, we observed that juglone affected survival in the rotifers in a dose-dependent manner
between 0.02 to 20 μM, and that treatment at above 2 μM showed acute toxicity causing the animals to die within a few hours.
Next, we found the difference in survival time between the two species exposed to 20 μM juglone: B. rotundiformis was significantly more tolerant against the substance than the allied species B. plicatilis. The findings suggest that exploring the basis of species-specific abilities to persist under oxidative stress will be of
great interest to uncover the underlying mechanisms governing the stress resistance of the rotifer, as well as contributing
to their stable mass production for aquaculture. 相似文献
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Tatsuo NAKAHARA Yoshihisa UENOYAMA Akira IWASE Shinya OISHI Sho NAKAMURA Shiori MINABE Youki WATANABE Chikaya DEURA Taro NOGUCHI Nobutaka FUJII Fumitaka KIKKAWA Kei-ichiro MAEDA Hiroko TSUKAMURA 《The Journal of reproduction and development》2013,59(5):479-484
Puberty in mammals is timed by an increase in gonadotropin-releasing hormone (GnRH)
secretion. Previous studies have shown involvement of the two neuropeptides,
kisspeptin and neurokinin B (NKB), in controlling puberty onset. Little is known
about the role of the other key neuropeptide, dynorphin, in controlling puberty
onset, although these three neuropeptides colocalize in the arcuate kisspeptin
neurons. The arcuate kisspeptin neuron, which is also referred to as the KNDy neuron,
has recently been considered to play a role as an intrinsic source of the GnRH pulse
generator. The present study aimed to determine if attenuation of inhibitory
dynorphin-kappa-opioid receptor (KOR) signaling triggers the initiation of puberty in
normal developing female rats. The present study also determined if stimulatory
NKB-neurokinin 3 receptor (NK3R) signaling advances puberty onset. Female
Wistar-Imamichi rats were weaned and intraperitoneally implanted with osmotic
minipumps filled with nor-binaltorphimine (nor-BNI), a KOR antagonist, or senktide, a
NK3R agonist, at 20 days of age. Fourteen days of intraperitoneal infusion of nor-BNI
or senktide advanced puberty onset, manifested as vaginal opening and the first
vaginal estrus in female rats. Frequent blood sampling showed that nor-BNI
significantly increased luteinizing hormone (LH) pulse frequency at 29 days of age
compared with vehicle-treated controls. Senktide tended to increase this frequency,
but its effect was not statistically significant. The present results suggest that
the inhibitory input of dynorphin-KOR signaling plays a role in the prepubertal
restraint of GnRH/LH secretion in normal developing female rats and that attenuation
of dynorphin-KOR signaling and increase in NKB-NK3R signaling trigger the onset of
puberty in female rats. 相似文献
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