排序方式： 共有77条查询结果，搜索用时 15 毫秒
41.
42.
43.
We investigated the functions and ecological traits of seven individual ectomycorrhizal (ECM) fungal species derived from a Pinus thunbergii-dominated (nitrogen-poor) and a Robinia pseudoacacia-dominated (nitrogen-rich) area. P. thunbergii seedlings were inoculated with seven individual ECM fungal species and cultured under high nitrogen (nitrogen group) and low nitrogen (control group) conditions. Control seedlings were not inoculated with any ECM fungus. Seedlings harvested were examined for the numbers of non-mycorrhizal and ECM root tips, growth, nutrient status (nitrogen, phosphorus and carbon) and the activity of dehydrogenase and phosphomonoesterase in the root tips. The relationships among the growth, nutrient status and the enzymatic activity in the seedlings inoculated with each ECM fungal species were also analyzed by canonical discriminants. As the results, inoculation of ECM fungi made the plant growth significantly higher than those of non-inoculated seedlings. Plant growth significantly correlated with the phosphorus content, N:P ratio and phosphomonoesterase activity, especially in the nitrogen group. Dehydrogenase and phosphomonoesterase activities in the seedlings were higher when the ECM fungi from a nitrogen-rich area were inoculated than when those from a nitrogen-poor area were inoculated. The canonical discriminant analyses separated seedlings by inocula: no fungus, ECM fungi from a nitrogen-poor area, and those from a nitrogen-rich area. These results suggested the possibility that nitrogen deposition caused P shortage and the P absorbing ability was higher in the ECM fungi in nitrogen-rich forests than those in nitrogen-poor forests. 相似文献
44.
Hironori SATOH Ryota TERASHIMA Mitsumori KAWAMINAMI Shiro KURUSU 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2021,83(9):1443
We determined a comprehensive immunohistochemistry of putative isoforms of enzymes for prostaglandin (PG) F2α and PGE2 biosynthesis and these PGs levels in placenta and fetal membrane of normal pregnant rats in vivo. Placenta and fetal membrane showed positive immunoreactions for phospholipase A2 group 4A, but not group 2A, and cyclooxygenase (COX)-1 rather than COX-2. They showed positive immunoreactions for at least one isoform of each of PGF synthase and PGE synthase with tissue-dependent variations. PGF2α and PGE2 levels in both tissues were highest on day 12 and declined and remained low thereafter. Obtained data would be the basic information on the primary PGs synthesis in rat placenta and fetal membrane in normal pregnancy. 相似文献
45.
Taiki Mori Seiichi Ohta Shigehiro Ishizuka Ryota Konda Agus Wicaksono Joko Heriyanto Arisman Hardjono 《Biology and Fertility of Soils》2013,49(1):13-21
An incubation experiment was conducted to examine the effects of phosphorus (P) addition with and without ammonium, nitrate, or glucose on N2O and NO emissions from soil taken under Acacia mangium plantation and incubated at 100 % water-filled pore space (WFPS). Additions of NO 3 ? stimulated the N2O and NO emissions while NH 4 + did not, showing that denitrification was the main process of N2O and NO production in the study condition. When NO 3 ? was added with P significantly (P?<?0.05) increased N2O emissions regardless of the ratio of the added nitrogen and carbon, suggesting that P addition stimulated denitrification activity. The activation of denitrification by P addition is possibly attributed to two mechanisms: (1) the added-P stimulated denitrification by relieving P shortage for denitrifying bacteria and (2) the added-P stimulated activity of heterotrophic soil microflora with increased O2 consumption promoting the development of anaerobic conditions with stimulation of denitrification. 相似文献
46.
Effects of sedimentation on an endangered benthic fish,Cobitis shikokuensis: is sediment‐free habitat a requirement or a preference? 
下载免费PDF全文
下载免费PDF全文 A negative correlation between the degree of fine sediment deposition and the abundance of stream benthic fishes has often been reported, although the causal mechanisms for this effect are not fully understood. To better understand the influence of sedimentation, it is important to clarify whether it alters the habitat required by fish, or merely preferred by them. We conducted two enclosure experiments in the field to examine (i) whether an endangered benthic fish, Cobitis shikokuensis, prefers sediment‐free substrate and (ii) whether fine sediment deposition has negative effects on the physiological condition of C. shikokuensis. The first experiment, which used three types of substrates, ‘cobble’, ‘pebble’ and ‘mixture of fine sediment and pebbles’, showed that C. shikokuensis avoided the mixture. The second experiment, which compared the physiological condition of fish reared in enclosures with either a pebble or mixture substrate, showed that the condition of the fish in the latter group declined more quickly. These results suggest that, for C. shikokuensis, sediment‐free substrate is a habitat requirement, not merely a preference, and that excessive input of fine sediment due to human activities can cause a decline in the population of this species. 相似文献
47.
Yuichi MIYAGAWA Ryota AKABANE Mizuki OGAWA Masayoshi NAGAKAWA Hirosumi MIYAKAWA Naoyuki TAKEMURA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2020,82(12):1828
Serum cystatin C levels (CysC) are used in human medicine to document progressive kidney failure. Although CysC are not thought to be useful for the diagnosis of kidney dysfunction in dogs, there has been no specific consideration of body weight as a confounding issue. The aim of this study was to assess that the utility of CysC for the diagnosis of decreased glomerular filtration rate (GFR) in smaller vs. larger dogs. In clinically healthy dogs, serum creatinine (Cre) and CysC correlate directly with body weight; we found that dogs weighing <20 kg had significantly lower CysC than those weighing ≥20 kg (0.27 ± 0.07 vs. 0.34 ± 0.05 mg/l, respectively, P<0.001). In dogs weighing <20 kg, CysC had superior diagnostic accuracy for the detection of mildly decreased plasma iohexol clearance (PCio) (<1.8 ml/min/kg) compared with Cre (sensitivity 100% vs. 80.9% and specificity 100% vs. 85.7%); this was not true for dogs weighing ≥20 kg. Additionally, using a cut-off PCio of <1.8 ml/min/kg, the area under receiver-operating characteristics curve (AUC) of CysC was significantly higher than that of Cre in dogs weighing <20 kg (P<0.05); this was not true for dogs weighing ≥20 kg (P=0.695). In conclusion, CysC is a useful marker for the detection of a mild decreasing GFR compared with Cre in dogs weighing <20 kg. 相似文献
48.
Ogo S Kabe R Uehara K Kure B Nishimura T Menon SC Harada R Fukuzumi S Higuchi Y Ohhara T Tamada T Kuroki R 《Science (New York, N.Y.)》2007,316(5824):585-587
Models of the active site in [NiFe]hydrogenase enzymes have proven challenging to prepare. We isolated a paramagnetic dinuclear nickel-ruthenium complex with a bridging hydrido ligand from the heterolytic cleavage of H2 by a dinuclear NiRu aqua complex in water under ambient conditions (20 degrees C and 1 atmosphere pressure). The structure of the hexacoordinate Ni(mu-H)Ru complex was unequivocally determined by neutron diffraction analysis, and it comes closest to an effective analog for the core structure of the proposed active form of the enzyme. 相似文献
49.
Imura A Tsuji Y Murata M Maeda R Kubota K Iwano A Obuse C Togashi K Tominaga M Kita N Tomiyama K Iijima J Nabeshima Y Fujioka M Asato R Tanaka S Kojima K Ito J Nozaki K Hashimoto N Ito T Nishio T Uchiyama T Fujimori T Nabeshima Y 《Science (New York, N.Y.)》2007,316(5831):1615-1618
alpha-klotho was identified as a gene associated with premature aging-like phenotypes characterized by short lifespan. In mice, we found the molecular association of alpha-Klotho (alpha-Kl) and Na+,K+-adenosine triphosphatase (Na+,K+-ATPase) and provide evidence for an increase of abundance of Na+,K+-ATPase at the plasma membrane. Low concentrations of extracellular free calcium ([Ca2+]e) rapidly induce regulated parathyroid hormone (PTH) secretion in an alpha-Kl- and Na+,K+-ATPase-dependent manner. The increased Na+ gradient created by Na+,K+-ATPase activity might drive the transepithelial transport of Ca2+ in cooperation with ion channels and transporters in the choroid plexus and the kidney. Our findings reveal fundamental roles of alpha-Kl in the regulation of calcium metabolism. 相似文献
50.