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31.
The rare earth elements are indispensible in modern technology, especially in the applications of permanent magnets. Very little quantitative information is available on rare earth elements used in permanent magnets, however. This study looks back to 1983, when neodymium‐iron‐boron (NdFeB) permanent magnets were first manufactured, and reaches to 2007, when the market of permanent magnets was well developed. We draw on the historical data on permanent magnets from China, Japan, the United States, and Europe to provide the first estimates of global in‐use stocks for four rare earth elements—praseodymium (Pr), neodymium (Nd), terbium (Tb), and dysprosium (Dy)—in NdFeB permanent magnets. In‐use stocks amount to 62.6 gigagrams (Gg) Nd, 15.7 Gg Pr, 15.7 Gg Dy, and 3.1 Gg Tb; these stocks, if efficiently recycled, could provide a valuable supplement to geological stocks as they are almost four times the 2007 annual extraction rate of the individual elements. 相似文献
32.
Narikawa R Fukushima Y Ishizuka T Itoh S Ikeuchi M 《Journal of molecular biology》2008,380(5):844-855
We report the discovery of a novel cyanobacteriochrome, the green/red photoreceptor AnPixJ (All1069), isolated from the heterocyst-forming cyanobacterium Anabaena (Nostoc) sp. PCC 7120. Cyanobacteriochromes are a recently emerging tetrapyrrole-based photoreceptor superfamily that are distantly related to the conventional red/far-red photoreceptor phytochromes (Phys). The chromophore-binding domains of AnPixJ produced in cyanobacterial and Escherichia coli cells both showed a reversible and full photoconversion between a green-absorbing form (λmax = 543 nm) and a red-absorbing form (λmax = 648 nm). Denaturation analysis revealed that the green-absorbing form and the red-absorbing form covalently ligated phycocyanobilin with E-configuration and Z-configuration at the C15C16 double bond, respectively. Time-resolved spectral analysis showed the formation of the first intermediate state peaking at 680 nm from the dark-stable red-absorbing form. This step resembles the first photoconversion step from the red-absorbing form to the red-shifted lumi-R intermediate state of the Phys. These results suggest that the Pr of AnPixJ is almost equivalent to that of the Phys and starts a primary photoreaction with Z-to-E isomerization in a mechanism similar to that in the Phys, but is finally photoconverted to the unique green-absorbing form. 相似文献
33.
Vladimir D. Kreslavski Dmitry A. Los Franz-Josef Schmitt Sergey K. Zharmukhamedov Vladimir V. Kuznetsov Suleyman I. Allakhverdiev 《BBA》2018,1859(5):400-408
This review describes the phytochrome system in higher plants and cyanobacteria and its role in regulation of photosynthetic processes and stress protection of the photosynthetic apparatus. A relationship between the content of the different phytochromes, the changes in the ratios of the physiologically active forms of phytochromes to their total pool and the resulting influence on photosynthetic processes is reviewed. The role of the phytochromes in the regulation of the expression of genes encoding key photosynthetic proteins, antioxidant enzymes and other components involved in stress signaling is elucidated. 相似文献
34.
Caio Junior Balduino Coutinho Rodrigues Wendell Marcelo de Souza Perinotto Walter Orlando Beys da Silva Lucélia Santi Markus Berger Allan Felipe Marciano 《Biocontrol Science and Technology》2016,26(2):239-249
Beauveria bassiana s.l. is a cosmopolitan fungus used in the control of different species of arthropods. The current study explored the virulence for ticks, proteolytic and lipolytic activities of 10 Brazilian B. bassiana s.l. isolates. For this purpose, Rhipicephalus microplus biological parameters was evaluated after immersion of the engorged females in fungal suspension (108 conidia mL?1) and the enzymatic activities were performed posteriorly the fungal growth in minimal medium. After the biological assays, five isolates changed all parameters analysed with highest efficacy of approximately 61% (CG 206) and 66% (CG 481). However, we observed that the most virulent isolates did not show the highest enzymatic activities. Interestingly, CG 500, considered an isolate of intermediate efficacy, demonstrated higher enzymatic activities than the other isolates in four of five analyses (total protease, Pr1, Pr2 and lipase; p?.05). Based on these data, it seems reasonable to suggest that these enzymatic activities should not be used as markers of virulence for these fungal isolates. It is noteworthy that complementary studies regarding chitinase analyses, gene expression, production of toxins and hydrophobicity of conidia can be used in the selection of pathogenic isolates. 相似文献
35.
36.
We have successfully developed a system to produce full-length plant phytochrome assembled with phytochromobilin in Pichia pastoris by co-expressing apophytochromes and chromophore biosynthetic genes, heme oxygenase (HY1) and phytochromobilin synthase (HY2) from Arabidopsis. Affinity-purified phytochrome proteins from Pichia cells displayed zinc fluorescence indicating chromophore attachment. Spectroscopic analyses showed absorbance maximum peaks identical to in vitro reconstituted phytochromobilin-assembled phytochromes, suggesting that the co-expression system is effective to generate holo-phytochromes. Moreover, mitochondria localization of the phytochromobilin biosynthetic genes increased the efficiency of holophytochrome biosynthesis. Therefore, this system provides an excellent source of holophytochromes, including oat phytochrome A and Arabidopsis phytochrome B. 相似文献
37.
Secretion of catabolic extracellular enzymes (ECE) is the hallmark of the infection of insects through the cuticle by entomopathogenic
fungi (EPF). In this paper, we show that germinating conidia of Beauveria bassiana (Bb) regulate the synthesis of ECE through a multiple control mode during the initial stages of germination. We tested Bb
conidial growth on aphid exuviae with or without supplementation of additional carbon and/or nitrogen (C/N) compounds. To
understand the interrelation between conidial germination during growth, the synthesis of ECE activity, free amino nitrogen
(FAN), glucose and fungal dry weight biomass were measured. Immediately (0.25 h) upon incubation of conidia, activity of subtilisin-like
Pr1 and trypsin-like Pr2 enzymes and chitinase (NAGase) was observed in the culture filtrates. At 0.25 h, addition of exogenous
C-source resulted in higher activities of Pr1 and Pr2, respectively. Conversely at 0.25 h, addition of N-sources repressed
the synthesis of Pr2, but that of Pr1. C/N repression was observed only for exponentially growing mycelia. NAGase activity
remained at basal level and unaffected by added C/N. We conclude that C/N repression occurs only when it is necessary for
the Bb infective structures to establish a nutritional relationship with the host structures. 相似文献
38.
The penetration of light through soil 总被引:9,自引:3,他引:6
Abstract There has been little written on the penetration of light through soil. In this review, we attempt to collate most of the work that has been published on this topic in order to stimulate further research and to clarify the often-confused literature. Light penetration can be measured directly with, for example, a spectroradiometer, or indirectly by using germination of light-sensitive seeds or the presence of growing algae as bioindicators. Although the penetration of light through soil is greatly affected by factors such as soil moisture content and particle size and colour, it generally appears that physiologically and ecologically significant amounts of light rarely penetrate more than 4–5 mm through the soil, and may often penetrate much less than this. Any penetration beyond 10 mm would generally not be significant, especially as most soils are covered with litter, algae or lichens, or are shaded from direct sunlight. However, for some light-stimulated geo-tropic responses of roots, which can be sensitive to very low fluences, the penetration of light to greater depths could well be significant. The role of light in soil in directing root growth is also discussed. 相似文献
39.
P. Giridhar M. Bhushana Reddy G. Neelima R. Ramanaiah K. Nagamuni Reddy V. Sahadeva Reddy B. Sudhakar Reddy 《Luminescence》2016,31(6):1237-1241
This article reports on the optical characterization of Pr3+‐, Er3+‐ and Nd3+‐doped cadmium lead boro tellurite (CLBT) glasses prepared using the melt quenching method. The visible–near infrared (Vis–NIR) absorption spectra of these glasses were analyzed systematically. On measuring the NIR emission spectra of Er3+:CLBT glasses, a broad emission band centered at 1536 nm (4I13/2 → 4I15/2) was observed, as were three NIR emission bands at 900 nm (4F3/2 → 4I9/2), 1069 nm (4F3/2 → 4I11/2) and 1338 nm (4F3/2 → 4I13/2) from Nd3+:CLBT glasses and an NIR emission band at 1334 nm (1G4 → 3H5) from Pr3+:CLBT glasses at an excitation wavelength (λex) of 514.5 nm (Ar+ laser). Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
40.
D-Arg2-dermorphin tetrapeptide analogs: a potent and long-lasting analgesic activity after subcutaneous administration 总被引:2,自引:0,他引:2
Y Sasaki M Matsui M Taguchi K Suzuki S Sakurada T Sato T Sakurada K Kisara 《Biochemical and biophysical research communications》1984,120(1):214-218
To examine pharmacological properties of D-Arg2-dermorphin tetrapeptides, six tetrapeptide analogs based on the following formulas, H-Tyr-D-Arg-Phe-Gly-OX (X = H, ethyl, n-propyl), H-Tyr-D-Arg-Phe-Sar-OX (Sar = sarcosine; X = H, methyl, ethyl), were prepared. All these analogs exhibited highly potent and long-lasting analgesia as compared with that of morphine after subcutaneous administration in mice. Among analogs tested, H-Tyr-D-Arg-Phe-Sar-OH showed the highest activities, which were 21, 30 and 58 times more active than morphine in the tail pressure, tail flick and phenylbenzoquinone writhing tests, respectively, on a molar basis. 相似文献