Effects of LH and PGF2alpha in equine dominant follicles observed by MDS     

Kojima AY  Kobayashi S  Acosta TJ  Kudo M  Miyamoto A  Takagi M  Miyazawa K  Sato K 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2002,64(2):119-122

Microdialysis System (MDS) is a novel technique used for investigation of molecule secretion between different cell populations. Local hormonal secretion at follicular wall has been still unclear. This MDS study was used to determine progesterone (P4), androstenedione (A4), estradiol-17beta (E2) and Prostaglandin F2alpha (PGF2alpha) release in mare pre-ovulatory follicles. Follicles larger than 30 mm were isolated from the ovary and follicular fluid aspirated for hormone assay. Follicular fluid collected from small, middle and large follicles were analyzed by EIA. The concentrations of P4 and PGF2alpha were similar among the different sizes of follicles. The release of A4 was observed in middle and large follicles. E2 concentration was observed in middle follicles and was higher in large follicles compared with middle follicles. Follicular wall was cut and incubated for MDS and when LH was infused, there was an increase in P4 and A4 release. PGF2alpha release was considerably high after LH infusion compared to the control group. Infusion of PGF2alpha increased P4 and A4 release but there was no change in E2 release. This results suggest that in pre-ovulatory follicles, LH stimulates theca interna cells and also PGF2alpha seemed to have a mediator role to induce steroid hormone production and luteinization of follicular cells. The nature of the mechanisms involved in selection of large follicles is still a perplexing research problem in reproduction.  相似文献   

Conservation rule of stem surface area: a hypothesis     

Akio Inoue  Tomohiro Nishizono 《European Journal of Forest Research》2015,134(4):599-608

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Prediction of Japanese green tea ranking by gas chromatography/mass spectrometry-based hydrophilic metabolite fingerprinting     

Pongsuwan W  Fukusaki E  Bamba T  Yonetani T  Yamahara T  Kobayashi A 《Journal of agricultural and food chemistry》2007,55(2):231-236

An innovative technique for green tea's quality determination was developed by means of metabolomics. Gas-chromatography coupled with time-of-flight mass spectrometry and multivariate data analysis was employed to evaluate the quality of green tea. Alteration of green tea varieties and manufacturing processes effects a variation in green tea metabolites, which leads to a classification of the green tea's grade. Therefore, metabolic fingerprinting of green tea samples of different qualities was studied. A set of ranked green tea samples from a Japanese commercial tea contest was analyzed with the aim of creating a reliable quality-prediction model. Several multivariate algorithms were performed. Among those, the partial least-squares projections to latent structures (PLS) analysis with the spectral filtering technique, orthogonal signal correction (OCS), was found to be the most practical approach. In addition, metabolites that play an important role in green tea's grade classification were identified.  相似文献   

Analysis of phloem exudate collected from fruit-bearing stems of coconut palm: Palm trees as a source of molecules circulating in sieve tubes     

Shin-ichi Nakamura  Akio Watanabe  Praphasri Chongpraditnun  Nobuo Suzui  Hiroaki Hayashi  Hiroyuki Hattori 《Soil Science and Plant Nutrition》2013,59(5):739-745

Sieve tubes have been attracting widespread research interest because of their possible role in mediating physiological signals within the whole plant. However, progress in research into the function of sieve tubes has been limited by the low volume of sap available. To overcome this problem, we attempted to collect phloem exudate from tropical coconut palm trees (Cocos nucifera L. cv. Namhom). As much as 3 to 15 mL of exudate per hour was collected from the cut surface of the plant's fruit-bearing stem. Our analyses revealed that the characterized profiles of sugars (sucrose: 339 mM), amino acids (total concentration: 17.1 mM), cations (potassium: 48.3 mM), and proteins (total concentration: 0.1 /-lg /-lL-1) in the exudate were mostly consistent with those of phloem sap or phloem exudate collected from rice plants, castor bean plants, etc. This exudate was assumed to reflect the composition of the phloem sap from the source organs of coconut palm trees. The large volume of exudate collected contributed significantly to the analyses of the various compounds in the stream of sieve tubes.  相似文献   

Tea plant (Camellia sinensis L.) roots secrete oxalic acid and caffeine into medium containing aluminum     

Akio Morita  Osamu Yanagisawa  Setsuko Maeda  Satoshi Takatsu  Takashi Ikka 《Soil Science and Plant Nutrition》2013,59(6):796-802

We examined the response of the tea plant (Camellia sinensis L.) to aluminum (Al) exposure under sterile conditions, focusing specifically on the secretion of low molecular mass organic compounds from roots. After germination in agar medium, tea seedlings together with medium were placed on agar containing 0.4?mM Al with 0.2% hematoxyline (hematoxylin-Al medium). The purple color of the hematoxylin-Al medium was observed to fade gradually, until none of the color remained 6 days later. The tea seedlings were then treated with simple calcium solution (0.2?mM, at pH 4.2) containing AlCl₃, which ranged in concentration from 0 to 0.8?mM, for 24?hrs. The amount of oxalate secreted into the medium increased as the external Al concentration increased, while the concentrations of malate and citrate in the medium remained unchanged. Oxalate secretion started within 30?min after Al exposure and increased linearly thereafter. The findings demonstrated that oxalate was a key compound in the Al-tolerance mechanism employed by the tea plant, which detoxifies Al³⁺ externally in the rhizosphere. In addition to oxalate, caffeine was also secreted by tea roots in response to Al exposure. It is possible that caffeine excretion from the roots of tea plants may stimulate root growth through the inhibition of callose deposition in root tips.  相似文献   

弱光照射和无机营养供给对冷藏绿芦笋品质变化的影响   总被引：9，自引：0，他引：9  

顾振新  饭本光雄  田川彰南  李式军 《南京农业大学学报》2001,24(4):84-88

绿芦笋嫩茎基部切口插入含有N、P、K营养的琼脂凝胶中 ,在 (6± 0 2 )℃下贮藏。贮藏期间 ,分别以有效光量子束密度 (PPFD)为 2 μmol·m-2 ·s-1的红色发光二极管和白色荧光灯作为弱光源 ,每天 2 4h连续照射绿芦笋 2 1d。结果表明 ,红光和白光对冷藏绿芦笋品质的保持具有相似的效果。供给无机营养的处理在红光或白光照射下 ,色值 (a 和ΔE ab)变化率、粗纤维含量增长率和可溶性固形物减少率为最低 ,其次是无营养供给的红光或白光处理 ,以黑暗处理为最高 ;供给无机营养处理的芦笋嫩茎伸长率大于无营养处理的 ;光线照射与否和无机营养供给有无与芦笋失重率之间无明显相关性  相似文献   

Daily ration of Japanese Spanish mackerel Scomberomorus niphonius larvae     

Jun Shoji  Tsutomu Maehara  Mitsuhiro Aoyama  Hiroshi Fujimoto  Akio Iwamoto  Masaru Tanaka 《Fisheries Science》2001,67(2):238-245

SUMMARY: Diel successive samplings of Japanese Spanish mackerel Scomberomorus niphonius larvae were conducted throughout 24 h both in the sea and in captivity in order to estimate their daily ration. Using the Elliott and Persson model, the instantaneous gastric evacuation rate was estimated from the depletion of stomach contents (% dry bodyweight) with time during the night for wild fish (3.0–11.5 mm standard length) and from starvation experiments for reared fish (8, 10, and 15 days after hatching (DAH)). Japanese Spanish mackerel is a daylight feeder and exhibited piscivorous habits from first feeding both in the sea and in captivity. Feeding activity peaked at dusk. The estimated daily ration for wild larvae were 111.1 and 127.2% in 1996 and 1997, respectively; and those for reared larvae ranged from 90.6 to 111.7% of dry bodyweight. Based on the estimated value of daily rations for reared fish, the total number of newly hatched red sea bream Pagrus major larvae preyed by a Japanese Spanish mackerel from first feeding (5 DAH) to beginning of juvenile stage (20 DAH) in captivity was calculated to be 1139–1404.  相似文献   

Down regulation of hepatic PPARalpha function by AhR ligand   总被引：1，自引：0，他引：1  

Shaban Z  El-Shazly S  Abdelhady S  Fattouh I  Muzandu K  Ishizuka M  Kimura K  Kazusaka A  Fujita S 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2004,66(11):1377-1386

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Alterations of activities of cytosolic phospholipase A2 and arachidonic acid-metabolizing enzymes in di-(2-ethylhexyl)phthalate-induced testicular atrophy     

Kim HS  Ishizuka M  Kazusaka A  Fujita S 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2004,66(9):1119-1124

Di-(2-ethylhexyl) phthalate (DEHP), a peroxisome proliferator-activated receptor alpha (PPARalpha) ligand, alters the lipid composition of rat testis, yet the mechanism is unclear. In this study, we investigated the effect of DEHP on the synthesis and metabolism of arachidonic acid (AA), a precursor of eicosanoids, in the testis of prepubertal rats. DEHP (100 and 1,000 mg/kg, 5 days) administration caused a significant reduction in activity of cytosolic phospholipase A2 (cPLA2), the rate-limiting enzyme in the AA and eicosanoid synthesis pathways. DEHP increased the expression of 12-lipoxygenase (12-LOX) in rat testis, whereas cyclooxygenase-2 (COX-2) expression was not altered. Cytochrome P450 4A1 (CYP4A1), a product of a PPARalpha-regulated gene, was markedly increased in the testis by DEHP administration. Taken together, DEHP suppresses cPLA2 activity and induces the AA metabolizing enzymes such as 12-LOX and CYP4A1, resulting in the reduction of AA level. These data suggest that altered AA metabolic cascades may be related to the decrease of testosterone concentration in DEHP-induced testicular atrophy.  相似文献   

Relative changes in mRNA expression of angiopoietins and receptors tie in bovine corpus luteum during estrous cycle and prostaglandin F2alpha-induced luteolysis: a possible mechanism for the initiation of luteal regression     

Tanaka J  Acosta TJ  Berisha B  Tetsuka M  Matsui M  Kobayashi S  Schams D  Miyamoto A 《The Journal of reproduction and development》2004,50(6):619-626

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