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11.
Megumi Fujisue Masao Sakai Kiyotaka Yamanat 《Development, growth & differentiation》1991,33(4):341-351
The specification of the dorsoventral axis in naturally polyspermic eggs of the Japanese newt, Cynops pyrrhogaster , was first examined by studies on the spatial relationship between the dorsal midline of the future body plan and the sperm entrance points (SEPs 1 ). On local insemination, the dorsal blastopore lip was usually found to be formed opposite the SEPs, as in anuran monospermic eggs. Next the movements of the subcortical layer and the cortex were analyzed. "Subcortical rotation" was observed, similar to that of Xenopus laevis eggs with respect to its timing and extent, and its direction was shown to predict the embryonic axis of the eggs. Thus, the dorsoventral axis was concluded to be determined by essentially the same mechanism in the newt as in Xenopus .
Owing to their large size and long first cell cycle, newt eggs appear to be suitable material for study of subcortical rotation, but their behavior is unique in that subcortical rotation occurs in only the vegetal hemisphere so that the subcortical layer stretches in the future dorsal side. Studies on the movement of Nile blue spots suggested that the cytoplasm under the cortex in newt eggs consists of two layers. 相似文献
Owing to their large size and long first cell cycle, newt eggs appear to be suitable material for study of subcortical rotation, but their behavior is unique in that subcortical rotation occurs in only the vegetal hemisphere so that the subcortical layer stretches in the future dorsal side. Studies on the movement of Nile blue spots suggested that the cytoplasm under the cortex in newt eggs consists of two layers. 相似文献
12.
Tokuo Ogawa Junichi Sugenoya Norikazu Ohnishi Keiko Natsume Megumi Ochiai Motohiko Nishida Norihiko Shinoda Kenichi Katoh Ritsuko Imamura 《International journal of biometeorology》1991,35(1):18-23
In an attempt to detect differences in the thermal effect of infrared irradiation of different wavelengths, transient sweating response to infrared irradiation in various spectral regions was examined. In Series 1, the ventral or dorsal surface of the nude subject was irradiated repetitively for a period of 4 min (2 min on, 2 min off) by each of three kinds of infrared heaters with main emissivity in near-infrared (NIR; 0.7–2.8 m), intermediate-infrared (MIR; 1.5–5.8 m), and far-infrared (FIR; 2.8–25 m) regions. The sweating response on a non-irradiated area tended to be the greatest with MIR, while the magnitude of the sweating response on the irradiated area showed no consistent differences among various wavelengths. The results infer that MIR stimulated cutaneous thomoreceptors most effectively, while its direct effect on local sweat gland activity was minimal. In Series 2, the effects of 9–12 min irradiations in more restricted ranges of wavelength were compared by the combination of the three kinds of heaters with filters (translucent to wavelength ranges of 1.3–2.7, 2.7–3.5, 3.6–8.0 m, respectively). The sweating response on a remote area was predominantly greater with the range of 2.7–3.5 m than with the other wavelength ranges, while the local effect on sweating was minimal with this range. The results of Series 2 reinforce those of Series 1, indicating that the degree of stimulation of cutaneous thermoreceptors and of direct thermal effect on sweat gland activity differ with spectral regions incident on the skin, thus affecting local and remote effects on the sweating response. 相似文献
13.
Hiide Yoshino Nobuyuki Miyatani Megumi Saito Toshio Ariga Alessandra Lugaresi Norman Latov Yasunori Kushi Takeshi Kasama Robert K. Yu 《Journal of neurochemistry》1992,59(5):1684-1691
The gangliosides GM1 and GD1b have recently been reported to be potential target antigens in human motor neuron disease (MND) or motor neuropathy. The mechanism for selective motoneuron and motor nerve impairment by the antibodies directed against these gangliosides, however, is not fully understood. We recently investigated the ganglioside composition of isolated bovine spinal motoneurons and found that the ganglioside pattern of the isolated motoneurons was extremely complex. GM1, GD1a, GD1b, and GT1b, which are major ganglioside components of CNS tissues, were only minor species in motoneurons. Among the various ganglioside species in motoneurons, several were immunoreactive to sera from patients with MND and motor neuropathy. One of these gangliosides was purified from bovine spinal cord and characterized as N-glycolylneuraminic acid-containing GM1 [GM1(NeuGc)] by compositional analysis, fast atom bombardment mass spectra, and the use of specific antibodies. Among seven sera with anti-GM1 antibody activities, five sera reacted with GM1(NeuGc) and two did not. Two other gangliosides, which were recognized by another patient's serum, appeared to be specific for motoneurons. We conclude that motoneurons contained, in addition to the known ganglioside antigens GM1 and GD1b, other specific ganglioside antigens that could be recognized by sera from patients with MND and motor neuropathy. 相似文献
14.
Hyperimmune and high-titered polyclonal pneumococcal antisera, specific for cross-reactive types within groups, were produced in adult rabbits. Purified capsular polysaccharide was injected intravenously into adult rabbits. One week later, these rabbits were given multiple intravenous injections of formalin-inactivated pneumococci of the cross-reactive type by an established method. Each of the resultant antisera were specific for the cross-reactive type indicating that the previous injection of the polysaccharide had induced epitope-specific tolerance. This method was successful for production of antisera against pneumococcal types 6A, 6B, 9N, 9V, 19F and 19A. Polyclonal rabbit pneumococcal antisera have some advantages over murine monoclonal antibodies for serologic studies and this method should be applicable for producing type-specific antibodies to cross-reactive polysaccharides of clinical interest. Further, this method is simpler and generally produces higher titered monovalent (factor) reagents than absorbed antisera. 相似文献
15.
Natsuki Osaka Yu kanesaki Megumi Watanabe Satoru Watanabe Taku Chibazakura Hiraku Takada Hirofumi Yoshikawa Kei Asai 《Molecular microbiology》2020,113(6):1155-1169
In bacteria, guanosine (penta)tetra-phosphate ([p]ppGpp) is essential for controlling intracellular metabolism that is needed to adapt to environmental changes, such as amino acid starvation. The (p)ppGpp0 strain of Bacillus subtilis, which lacks (p)ppGpp synthetase, is unable to form colonies on minimal medium. Here, we found suppressor mutations in the (p)ppGpp0 strain, in the purine nucleotide biosynthesis genes, prs, purF and rpoB/C, which encode RNA polymerase core enzymes. In comparing our work with prior studies of ppGpp0 suppressors, we discovered that methionine addition masks the suppression on minimal medium, especially of rpoB/C mutations. Furthermore, methionine addition increases intracellular GTP in rpoB suppressor and this effect is decreased by inhibiting GTP biosynthesis, indicating that methionine addition activated GTP biosynthesis and inhibited growth under amino acid starvation conditions in (p)ppGpp0 backgrounds. Furthermore, we propose that the increase in intracellular GTP levels induced by methionine is due to methionine derivatives that increase the activity of the de novo GTP biosynthesis enzyme, GuaB. Our study sheds light on the potential relationship between GTP homeostasis and methionine metabolism, which may be the key to adapting to environmental changes. 相似文献
16.
17.
Kenta Shirasawa Kohei Ishii Cholgwang Kim Tomohiro Ban Munenori Suzuki Takashi Ito Toshiya Muranaka Megumi Kobayashi Noriko Nagata Sachiko Isobe Satoshi Tabata 《Molecular breeding : new strategies in plant improvement》2013,31(1):101-110
Capsicum spp. are widely cultivated for use as vegetables and spices. The Kihara Institute for Biological Research, Yokohama City University, Japan, has stocks of approximately 800 lines of Capsicum spp. collected from various regions of Central and South America, the regions of origin for Capsicum spp. In this study, 5,751 primer pairs for simple sequence repeat markers, based on 118,060 publicly available sequences of expressed sequence tags of Capsicum annuum, were designed and subjected to a similarity search against the genomic sequence of tomato, a model Solanaceae species. Nucleotide sequences spanning 2,245 C. annuum markers were successfully mapped onto the tomato genome, and 96 of these, which spanned the entire tomato genome, were selected for further analysis. In genotyping analysis, 60 out of the 77 markers that produced specific DNA amplicons showed polymorphism among the Capsicum lines examined. On the basis of the resulting data, the 192 tested lines were grouped into five main clusters. The additional sequencing analysis of the plastid genes, matK and rbcL, divided the resources into three groups. As a result, 19 marker loci exhibited genotypes specific to species and cluster, suggesting that the DNA markers are useful for species identification. Information on the DNA markers will contribute to Capsicum genetics, genomics, and breeding. 相似文献
18.
19.
Muichi Kaito Shin-Ichi Araya Yuichiro Gondo Michiyo Fujita Naomi Minato Megumi Nakanishi Makoto Matsui 《PloS one》2013,8(8)
Background and Purpose
The most common strategy for treating patients with acute ischemic stroke is thrombolytic therapy, though only a few patients receive benefits because of the narrow time window. Inflammation occurring in the central nervous system (CNS) in association with ischemia is caused by immune cells including monocytes and involved in lesion expansion. If the specific roles of monocyte subsets in stroke can be revealed, they may become an effective target for new treatment strategies.Methods
We performed immunological examinations of 36 consecutive ischemic stroke patients within 2 days of onset and compared the results with 24 age-matched patients with degenerative disorders. The stroke patients were repeatedly tested for the proportions of monocyte subsets in blood, and serum levels of pro- and anti-inflammatory cytokines immediately after admission, on days 3-7 and 12-16 after stroke onset, and on the day of discharge. In addition, immunological measurements were analyzed for relationships to stroke subtypes and complications, including progressive infarction (PI) and stroke-associated infection (SAI).Results
Monocyte count was significantly increased from 0–16 days after stroke as compared to the controls (p<0.05). CD14highCD16- classical and CD14highCD16+ intermediate monocytes were significantly increased from 0-7 and 3-16 days after stroke, respectively (p<0.05), whereas CD14 dimCD16high non-classical monocytes were decreased from 0–7 days (p<0.05). Cardioembolic infarction was associated with a persistent increase in intermediate monocytes. Furthermore, intermediate monocytes were significantly increased in patients with PI (p<0.05), while non-classical monocytes were decreased in those with SAI (p<0.05). IL-17A levels were positively correlated with monocyte count (r=0.485, p=0.012) as well as the percentage of non-classical monocytes (r=0.423, p=0.028), and negatively with that of classical monocytes (r=-0.51, p=0.007) during days 12-16.Conclusions
Our findings suggest that CD14highCD16+ intermediate monocytes have a role in CNS tissue damage during acute and subacute phases in ischemic stroke especially in relation to cardioembolism. 相似文献20.
Miwako Matsuki-Fukushima Junko Fujita-Yoshigaki Masataka Murakami Osamu Katsumata-Kato Megumi Yokoyama Hiroshi Sugiya 《The Journal of membrane biology》2013,246(3):209-214
In secretory granules and vesicles, membrane transporters have been predicted to permeate water molecules, ions and/or small solutes to swell the granules and promote membrane fusion. We have previously demonstrated that aquaporin-6 (AQP6), a water channel protein, which permeates anions, is localized in rat parotid secretory granules (Matsuki-Fukushima et al., Cell Tissue Res 332:73–80, 2008). Because the localization of AQP6 in other organs is restricted to cytosolic vesicles, the native function or functions of AQP6 in vivo has not been well determined. To characterize the channel property in granule membranes, the solute permeation-induced lysis of purified secretory granules is a useful marker. To analyze the role of AQP6 in secretory granule membranes, we used Hg2+, which is known to activate AQP6, and investigated the characteristics of solute permeability in rat parotid secretory granule lysis induced by Hg2+ (Hg lysis). The kinetics of osmotic secretory granule lysis in an iso-osmotic KCl solution was monitored by the decay of optical density at 540 nm using a spectrophotometer. Osmotic secretory granule lysis was markedly facilitated in the presence of 0.5–2.0 μM Hg2+, concentrations that activate AQP6. The Hg lysis was completely blocked by β-mercaptoethanol which disrupts Hg2+-binding, or by removal of chloride ions from the reaction medium. An anion channel blocker, DIDS, which does not affect AQP6, discriminated between DIDS-insensitive and sensitive components in Hg lysis. These results suggest that Hg lysis is required for anion permeability through the protein transporter. Hg lysis depended on anion conductance with a sequence of NO3 ? > Br? > I? > Cl? and was facilitated by acidic pH. The anion selectivity for NO3 ? and the acidic pH sensitivity were similar to the channel properties of AQP6. Taken together, it is likely that AQP6 permeates halide group anions as a Hg2+-sensitive anion channel in rat parotid secretory granules. 相似文献