A multi-step inflow method for estimating hydraulic conductivity at low pressure under the wetting process   总被引：2，自引：0，他引：2  

Haruyuki Fujimaki  Mitsuhiro Inoue  Katsumi Konishi 《Geoderma》2004,120(3-4):177-185

The accurate determination of the wetting soil hydraulic properties for a wide range of water contents is essential for studying and predicting infiltration processes. We present a laboratory infiltration method for determining hydraulic conductivity function, K(θ), in the low-to-medium water content range. An initially air-dry soil core is subjected to infiltration from the bottom where the pressure head, ψ_bot, is controlled through a membrane. As soon as the wetting front arrives at the soil surface, the top 0.5-cm layer is sliced for measurement of the water content. The ψ_bot is stepwise increased as the hydraulic equilibrium is nearly attained at each step. The wetting water retention function, ψ(θ), is determined by curve-fitting the equilibrium inflow data and from the independently measured data obtained from vapor equilibrium. The parameter in the K(θ) is estimated inversely using the cumulative inflow and water content of the sliced layer. This method is verified through comparisons with K(θ) obtained by the Boltzmann transform method. Although requiring an additional operation, the slicing procedure is found to be valuable in enhancing the reliability of the optimized parameter. A sensitivity analysis shows that water vapor movement would be negligible under our experimental conditions.  相似文献   

Genetic variation in barley landraces from Bhutan     

Takeo Konishi  Yuko Yano  Yoshihisa Fukushima 《Genetic Resources and Crop Evolution》1993,40(1):33-38

Summary In Bhutan, barley is usually grown in mountainous regions over 2,000 m elevation. The barleys investigated were six-rowed naked, and classified into three groups by spike and awn characters; lax spike and long awn, dense spike and long awn, and dense spike and elevated hood. They also varied in spike color; yellow, purple and black. For isozymes, there was no variation at Aat2 and Aat3 loci for aspartate aminotransferase in the Bhutanese barley.However, allelic variations at Est1, Est2 and Est4 loci for esterase were detected, and three genotypes consisting of their allelic combinations were found. Most of the collections were heterogeneous for these features. Combinations between spike-awn types and esterase genotypes were not at random, indicating that genetic diversities resulted from mechanical mixtures of different types. These types were distributed with geographical regularity in Bhutan. In comparing the spike-awn type and esterase genotype in barley collections from other regions of the Himalayas, the Bhutanese barleys were s-imilar to the Tibetan ones, but were much different from the Nepalese barleys. This suggests that the Bhutanese barleys had been introduced from Tibet.  相似文献   

Pharmacokinetic study of caffeic and rosmarinic acids in rats after oral administration     

Konishi Y  Hitomi Y  Yoshida M  Yoshioka E 《Journal of agricultural and food chemistry》2005,53(12):4740-4746

p-Coumaric and ferulic acid are actively taken up by monocarboxylic acid transporter (MCT), whereas gallic acid, caffeic acid (CA), and rosmarinic acid (RA) are absorbed by paracellular diffusion in human intestinal Caco-2 cells, although CA has low affinity for MCT. We previously demonstrated that p-coumaric acid has a much higher absorption efficiency than gallic acid in rats, owing to the MCT-mediated absorption of p-coumaric acid in vivo (J. Agric. Food Chem. 2004, 52, 2527-2532). Here, absorption of orally administered CA and RA in rats has been studied to investigate their intestinal absorption characteristics and pharmacokinetics in vivo and to compare the results with those of p-coumaric and gallic acids obtained under identical conditions. Rats were given 100 micromol/kg body weight of CA and RA, and blood was collected from the portal vein and abdominal artery after administration. CA, RA, and their metabolites were quantified by a coulometric detection method using HPLC-ECD. The serum concentration of intact CA and RA in the portal vein peaked at 10 min after administration, with a C(max) of 11.24 micromol/L for CA and 1.36 micromol/L for RA. The area under the curve (AUC) for intact CA and RA in the portal vein was calculated from the serum concentration-time profile to be 585.0 and 60.4 micromol min L-1, respectively. The absorption efficiency of CA was about 9.7-fold higher than that of RA. Overall, the absorption efficiency of these compounds in vivo increases in the order: gallic acid = RA < CA < p-coumaric acid, which is in good agreement with results obtained in Caco-2 cells in vitro.  相似文献   

Tea polyphenols inhibit the transport of dietary phenolic acids mediated by the monocarboxylic acid transporter (MCT) in intestinal Caco-2 cell monolayers     

Konishi Y  Kobayashi S  Shimizu M 《Journal of agricultural and food chemistry》2003,51(25):7296-7302

It was previously reported that a fluorescent marker dye, fluorescein, is transported via the monocarboxylic acid transporter (MCT). Fluorescein transport was competitively inhibited by MCT substrates such as ferulic and salicylic acids. Tea polyphenols, in particular, epigallocatechin gallate (EGCg) and epicatechin gallate (ECg), inhibited the transport of fluorescein. Tea polyphenols also inhibited the transport of salicylic and ferulic acids, suggesting tea polyphenols might be substrates of MCT. However, the transepithelial flux of tea polyphenols was much lower than that of the MCT substrates and was inversely correlated with the paracellular permeability of Caco-2 cell monolayers. These findings suggest that tea polyphenols are not substrates but inhibitors of MCT. Furthermore, the transepithelial transport of these polyphenols is mainly via paracellular diffusion. However, directional transport of ECg and EGCg from the basolateral to the apical side was observed, indicating that the behavior of tea polyphenols in the intestinal epithelium is complex.  相似文献   

Endocrine mechanisms responsible for different follicular development during the estrous cycle in Hatano high- and low-avoidance rats     

Jaroenporn S  Horii Y  Akieda-Asai S  Wang K  Nagaoka K  Ohta R  Shirota M  Watanabe G  Taya K 《The Journal of reproduction and development》2011,57(6):690-699

Hatano high- and low-avoidance rats (HAA and LAA strains, respectively) were selected and bred according to the avoidance rate in a shuttle-box task. Although they have clear strain differences in ovarian function, their endocrine mechanisms still remain to be clarified. Differences in female reproductive endocrinology between the strains were investigated by means of measuring the plasma concentration of reproductive hormones during the estrous cycle. LAA rats showed approximately threefold lower basal and surge levels of LH, a more than fourfold lower level of FSH surges and higher levels of inhibin A and inhibin B during the estrous cycle compared with the levels seen in HAA rats. The concentration of estradiol-17β in the proestrous stage was significantly lower in LAA rats than in HAA rats. Additionally, LH and FSH secretions from primary cultured anterior pituitary cells with or without in vitro GnRH stimulation were lower in the cells derived from LAA rats and, in terms of FSH secretion, were unresponsive to GnRH in contrast to cells derived from HAA rats. Although an increased number of preantral follicles in diestrus were observed in LAA rats, number of hCG-induced ovulation was lower in LAA rats. LAA rats may have much more follicle growth during the early stage of folliculogenesis, but most follicles might not grow into mature follicles. These results strongly suggest that the strain difference in ovarian function of these two Hatano rats is due to the difference in the regulation of hypothalamo-hypophyseal system for gonadotropins secretion.  相似文献   

Localization of a novel RNA-binding protein, SKIV2L2, to the nucleus in the round spermatids of mice     

Osman BA  Kawashima A  Tamba M  Satoh E  Kato Y  Iki A  Konishi K  Matsuda M  Okamura N 《The Journal of reproduction and development》2011,57(4):457-467

In our previous study (Kawashima et al., Biol Reprod 2009; 80: 1293-1304), we suggested that the first cycle of spermatogenesis recovered from busulfan-induced temporary arrest was a good model system to analyze the proteins expressed at the specific stages of spermatogenesis in the mouse, and this has been confirmed in the present paper. Namely, six-week-old mice were injected with busulfan at 20 mg/kg body weight. The germ cells except for the undifferentiated spermatogonia disappeared by 32 days after injection. The surviving spermatogonia started to proliferate, and spermatogenesis was entirely recovered about 77 days after injection. By proteome analysis of the busulfan-treated testis during the process of recovery of spermatogenesis, we identified a protein that was expected to be expressed in the spermatogenic cells as Superkiller viralicidic activity-2-like-2 (SKIV2L2). Skiv2l2 mRNA was found in the kidney, epididymis and heart as well as the testis. In the testis, Skiv2l2 mRNA was shown to be highly expressed in the spermatocytes at stages I to VI. On the other hand, SKIV2L2 protein was found to be predominantly localized in the nuclei of round spermatids. In accordance with the fact that SKIV2L2 belongs to the Ski2 family within the superfamily 2 of RNA helicases, it has been shown that SKIV2L2 has both the RNA-binding and ATPase activities.  相似文献   

Hormone-induced sexual differentiation of brain and behavior in zebra finches     

Gurney ME  Konishi M 《Science (New York, N.Y.)》1980,208(4450):1380-1383

The male zebra finch sings, whereas the female does not. This behavioral dimorphism is correlated with the presence of morphological sex differences within the neural substrate that mediates this behavior, the song system. When a female chick is exposed to 17beta-estradiol her song system is subsequently masculinized. Either testosterone or 5alpha-dihydrotestosterone may then induce such a female to sing when an adult.  相似文献   

A neural map of auditory space in the owl   总被引：11，自引：0，他引：11  

E I Knudsen  M Konishi 《Science (New York, N.Y.)》1978,200(4343):795-797

Auditory units that responded to sound only when it originated from a limited area of space were found in the lateral and anterior portions of the midbrain auditory nucleus of the owl (Tyto alba). The areas of space to which these units responded (their receptive fields) were largely independent of the nature and intensity of the sound stimulus. The units were arranged systematically within the midbrain auditory nucleus according to the relative locations of their receptive fields, thus creating a physiological map of auditory space.  相似文献   

Molecular basis of the nitrogen response in plants     

Yoshiaki Ueda  Mineko Konishi 《Soil Science and Plant Nutrition》2013,59(4):329-341

Nitrogen is an essential element for living organisms because it is a crucial constituent of biomolecules. Inadequate supply of usable nitrogen reduces plant growth and crop yield. The primary nitrogen sources for plants are nitrate and ammonium in soils, and plants have multiple layers of sensing and adaptive mechanisms that respond to the availability of these nutrients. The adaptive responses are called ‘nitrogen responses,’ which include morphological and physiological responses enabling plants to efficiently take up nitrogen and adapt to spatiotemporal fluctuations in nitrogen abundance in the field. In this review, we summarize the strategies that plants use to respond to changes in the nitrogen nutrient status in the soil and discuss different effects produced by nitrate and ammonium, emphasizing the important role of nitrate for plant growth. Recent studies revealed the molecular mechanism mediating the primary response to nitrate provision and the molecular mechanisms that coordinate the nitrogen response with responses to another macronutrient, phosphorus. We thus discuss these molecular mechanisms as well.  相似文献   

Ammonium uptake capacity and response of cytosolic glutamine synthetase 1;2 to ammonium supply are key factors for the adaptation of ammonium nutrition in Arabidopsis thaliana     

Takanori Yasuda  Noriyuki Konishi 《Soil Science and Plant Nutrition》2013,59(6):553-560

Plant requires nitrogen for the growth, and it use nitrate and ammonium from the environment. Plant suffers from the toxicity when excess ammonium is supplied as a sole nitrogen, although it could be a good nitrogen source for plant growth. We hypothesized that the different responses of ecotypes to ammonium nutrient could partly account for the adaptation of Arabidopsis to an ammonium environment. The purpose of this study is to understand the different responses of ecotypes in ammonium environment. The growth of Arabidopsis thaliana ecotypes, Columbia was compared to those of Arabidopsis thaliana ecotypes, Landsberg erecta in ammonium nutrient. The ratio of shoot dry weight to root dry weight was compared to evaluate the adaptation of two ecotypes. The shoot:root ratio of Landsberg was significantly higher than that of Columbia. T-DNA insertion in cytosolic glutamine synthetase 1;2, one of the essential ammonium assimilatory enzymes, led a decrease of shoot:root ratio. We also measured the isotope-labeled ammonium uptake and the expression levels of ammonium transporter genes, and also the expression of ammonium assimilatory genes, glutamine synthetase genes and glutamate synthase genes, in roots after ammonium re-supply using real-time polymerase chain reaction analysis. We found that (1) ammonium uptake of Landsberg erecta was higher than that of Columbia, when ammonium was supplied at higher concentration, and (2) cytosolic glutamine synthetase 1;2 was highly increased by ammonium supply in the root of Landsberg erecta. The present study suggested the importance of these two factors for adaptation of Arabidopsis to an ammonium-rich environment.  相似文献