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941.
With four soils differing in K supplying power and with four rice cultivars (Oryza sativa L.) differing in K uptake kinetic parameters, the relationship between K fertilizer application and soil redox status in rhizosphere and; the distribution of ferrous iron and other toxic substances on the root surface and in the rhizosphere; and the effect of K supply on uptake of reduced iron by rice plants have been studied.The results show that K application on K-deficient soils reduced the content of active reducing substances and ferrous iron in the soil, raised the soil redox potential in the rhizosphere, increased the Eh value of rice roots and lowered the content of iron in the rice plants. These effects of K varied with different rice cultivars. When no K fertilizer was applied, active reducing substances and ferrous iron in rhizosphere soils were decreased more by the rice cultivars absorbing K strongly (e.g. Shanyou 64) than by cultivars absorbing K weakly (e.g. Zhongguo 91). Therefore, the diminution of the toxic substances by K application in the weakly K-absorbing cultivars was more significant.The observation of a rhizobox separated by a nylon screen showed that appreciably more iron oxides, compared with the control, were deposited at or adjacent to the root surfaces of the rice plant supplied with K fertilizer, fully demonstrating the relationship between K nutrition and the total oxidizing power of rice plants. According to the distribution of active reducing substances and ferrous iron, the oxidizing range of the rice root extended in K application treatment a few centimeters away from the root plane. K application to rice affected the soil redox status in rhizosphere in many ways. The main effect was an increase of the oxidizing power of the rice root. As a result, the value of soil Eh was increased, the contents of active reducing substances and ferrous iron were lowered, as well as the number of oxygen consuming microorganisms. 相似文献
942.
以中晚熟水稻品种"吉粳811"为研究对象,于2013年和2014年在延吉市进行分期播种/移栽试验,分析了吉林省东部地区一季粳稻生长速度和产量对移栽期及温度变化的响应规律,确定该品种在研究地区的适宜播种期和移栽期,以减免低温冷害的影响。结果表明:播期/移栽期的推迟提升了生长季平均气温,水稻生长发育进程加快,有效生育期缩短,主要生长季内平均气温每升高1℃,水稻生长速率提升19%,生育期缩短5 d左右;吉林省东部地区水稻的适宜移栽温度为日均气温13.0℃,移栽过早或偏晚均导致减产;中晚熟品种水稻在4月18日前后播种、5月26日前后移栽可保证在霜前成熟,且产量高;中晚熟品种水稻移栽至成熟适宜活动积温为2280℃·d左右,活动积温每减少100℃·d,水稻产量下降1095 kg·hm~(-2)(约减产13%);积温不足导致水稻冷害发生,因而减产。 相似文献
943.
Characterization of biopharmaceutical proteins and assessment and understanding of the critical quality attributes (CQAs) is a significant part of biopharmaceutical product development and is routinely performed in vitro. In contrast, systematic analysis of the quality attributes in vivo is not as widespread, although metabolism and clearance of multiple variants of therapeutic proteins administered to non-human primates and human subjects may have a different impact on safety, efficacy and exposure. The major hurdles of such studies are usually sample availability and technical capability. In this study, we used affinity purification coupled with liquid chromatography and mass spectrometric analysis of the digested protein for consistent and simultaneous detection of the full amino acid sequence of a therapeutic IgG4 monoclonal antibody, MAB1. This methodology allowed us to assess in vivo changes of all sequence-related modifications and quality attributes of MAB1 over the duration of a preclinical pharmacokinetic study in cynomolgus monkeys. 相似文献
944.
《Bioorganic & medicinal chemistry》2016,24(16):3649-3656
Novel benzimidazolium salts were synthesized as N-heterocyclic carbene (NHC) precursors, these NHC precursors were metallated with Ag2O in dichloromethane at room temperature to give novel silver(I)–NHC complexes. Structures of these benzimidazolium salts and silver(I)–NHC complexes were characterized on the basis of elemental analysis, 1H NMR, 13C NMR, IR and LC–MS spectroscopic techniques. A series of benzimidazolium salts and silver(I)–NHC complexes were tested against standard bacterial strains: Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and the fungal strains: Candida albicans and Candida tropicalis. The results showed that benzimidazolium salts inhibited the growth of all bacteria and fungi strains and all silver(I)–NHC complexes performed good activities against different microorganisms. 相似文献
945.
Astrocytes with previous chronic exposure to amyloid β‐peptide fragment 1–40 suppress excitatory synaptic transmission 下载免费PDF全文
Hiroyuki Kawano Kohei Oyabu Hideaki Yamamoto Kei Eto Yuna Adaniya Kaori Kubota Takuya Watanabe Ayumi Hirano‐Iwata Junichi Nabekura Shutaro Katsurabayashi Katsunori Iwasaki 《Journal of neurochemistry》2017,143(6):624-634
946.
Bone histology is an important tool for uncovering life history traits of extinct animals, particularly those that lack modern analogs, such as the non-avian dinosaurs. In most studies, histological analyses preferentially focus on long bones for understanding growth rates and determining age. Here we show, by analyzing ornithischians (a stegosaur and an ornithopod), saurischians (a sauropod and a theropod), and a crocodile, rib histology is a suitable alternative. The estimated age for all sampled taxa ranges between 14 to 17 years for Lourinhanosaurus antunesi and 27 to 31 years estimated for Draconyx loureiroi. The theropod Baryonyx was skeletally mature around 23–25 years of age but showed unfused neurocentral sutures, a paedomorphic feature possibly related to aquatic locomotion. Our results show that ribs can contain a nearly complete growth record, and reveal important information about individual age, point of sexual maturity, and, in some cases, sex. Because ribs are more available than long bones, this method opens new possibilities for studying rare and incomplete fossils, including holotypes. 相似文献
947.
Dynamics of Docosahexaenoic Acid Metabolism in the Central Nervous System: Lack of Effect of Chronic Lithium Treatment 总被引:9,自引:0,他引:9
Using a method and model developed in our laboratory to quantitatively study brain phospholipid metabolism, in vivo rates of incorporation and turnover of docosahexaenoic acid in brain phospholipids were measured in awake rats. The results suggest that docosahexaenoate incorporation and turnover in brain phospholipids are more rapid than previously assumed and that this rapid turnover dilutes tracer specific activity in brain docoshexaenoyl-CoA pool due to release and recycling of unlabeled fatty acid from phospholipid metabolism. Fractional turnover rates for docosahexaenoate within phosphatidylinositol, choline glycerophospholipids, ethanolamine glycerophospholipids and phosphatidylserine were 17.7, 3.1, 1.2, and 0.2 %.h–1, respectively. Chronic lithium treatment, at a brain level considered to be therapeutic in humans (0.6 mol.g–1), had no effect on turnover of docosahexaenoic acid in individual brain phospholipids. Consistent with previous studies from our laboratory that chronic lithium decreased the turnover of arachidonic acid within brain phospholipids by up to 80% and attenuated brain phospholipase A2 activity, the lack of effect of lithium on docosahexaenoate recycling and turnover suggests that a target for lithium's action is an arachidonic acid-selective phospholipase A2. 相似文献
948.
Doebler JA 《Cell biology and toxicology》1999,15(5):279-289
Studies were conducted using a novel in vitro approach to investigate the efficacy of acetamidine hydrochloride (ACE) and guanidine hydrochloride (GUAN), previously shown to block gramicidin D (GRAM) channels in artificial membranes, in preventing the toxic effects of GRAM in NG108-15 (neuroblastoma×glioma hybrid) cells. Specifically, intracellular microelectrode techniques were employed to examine changes in membrane resting potential (V
m) and input resistance (R
in). At 1 mol/L, ACE significantly reduced loss of V
m induced by 1 or 10 g/ml GRAM, although higher concentrations of ACE did not afford enhanced antagonism. GUAN, in contrast, produced a concentration-dependent antagonism of GRAM-induced V
m and R
in loss, with high concentrations (10 or 100 mol/L) completely preventing diminutions in both V
m and R
in. In control cells superfused without GRAM, ACE produced a direct, concentration-dependent reduction in V
m and R
in, whereas GUAN hyperpolarized NG108-15 cells but did not alter R
in. These data represent the initial demonstration of the reversal of GRAM toxicity in an intact cell system. 相似文献
949.
M. K. Gaitonde Elizabeth Murray Vincent J. Cunningham 《Journal of neurochemistry》1989,52(5):1348-1352
The activity of phosphoglucose isomerase, its kinetic properties, and the effect of 6-phosphogluconate on its activity in the forward (glucose 6-phosphate----fructose 6-phosphate) and the reverse (fructose 6-phosphate----glucose 6-phosphate) reactions were determined in adult rat brain in vitro. The activity of phosphoglucose isomerase (in nmol/min/mg of whole brain protein) was 1,865 +/- 20 in the forward reaction and 1,756 +/- 32 in the reverse reaction at pH 7.5. It was 1,992 +/- 28 and 2,620 +/- 46, respectively, at pH 8.5. The apparent Km and Vmax of phosphoglucose isomerase were 0.593 +/- 0.031 mM and 2,291 +/- 61 nmol/min/mg of protein, respectively, for glucose 6-phosphate and 0.095 +/- 0.013 mM and 2,035 +/- 98 nmol/min/mg of protein, respectively, for fructose 6-phosphate. The activity of phosphoglucose isomerase was inhibited intensely and competitively by 6-phosphogluconate, with an apparent Ki of 0.048 +/- 0.005 mM for glucose 6-phosphate and 0.042 +/- 0.004 mM for fructose 6-phosphate as the substrate. With glucose 6-phosphate as the substrate, at concentrations from 0.05 to 0.5 mM, the activity of the enzyme was inhibited completely in the presence of 0.5-2.0 mM 6-phosphogluconate. With 0.05-0.2 mM fructose 6-phosphate as the substrate, it was inhibited greater than or equal to 85% at the same concentrations of the inhibitor. No significant changes were observed in the values of Km, Vmax, and Ki for phosphoglucose isomerase in the brain of 6-aminonicotinamide-treated rats.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
950.
人14p+标记染色体的分子细胞遗传学研究 总被引:1,自引:1,他引:1
一例23岁女性患者因近五、六年来出现胡须、四肢多毛及偶有月经不规则而就诊。细胞遗传学检查发现一个短臂明显增大的亚中着丝粒的14号标记染色体14p ·p 区域GTG显带呈浅染,C-带暗染,都呈均匀的染色区。硝酸银染色在p 远侧端显现一个Ag-NOR,其大小与正常近端着丝粒染色体的无明显差异。应用~3H标记的7.3 kb长的rRNA基因探针进行染色体原位杂交,自显影银颗粒沿整个p 区域分布,p 上的银颗粒数是正常近端着丝粒染色体短臂上银颗粒平均数的5倍。这些结果排除了Y或其他染色体参加的重排形成p 的可能性,并表明Ag-NOR的大小或NOR的数目并不一定与rRNA基因的数量成正比。研究Dp 或Gp 类型的染色体变异,对了解人二倍体细胞内rRNA基因表达的调控有重要意义。 相似文献