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61.
Akio Kamiya 《Physiologia plantarum》1998,104(1):50-55
In DCMU‐poisoned wild‐type and in non‐photosynthetic pigment mutant cells of Chlorella kessleri , grown heterotrophically with glucose as a carbon source and with nitrate as sole nitrogen source, the known blue light‐enhanced uptake of oxygen and breakdown of starch were reduced by staurosporine and K252a, both potent inhibitors of protein kinase C. This corresponded to sensitivity to these inhibitors of blue light‐induced uptake of nitrate of such organisms. Cells grown with ammonia as sole nitrogen source responded to short wavelength visible irradiation with an increase in oxygen uptake, and this, too, was inhibited by staurosporine and K252a. However, these cells did not show any blue light‐enhanced uptake of nitrate. From these results, enhanced consumption of oxygen under blue light cannot be a consequence of blue light‐induced protein phosphorylation involved in the light‐dependent uptake of nitrate. However, existence of a specific protein phosphorylation within the process of enhancement of oxygen uptake under blue light is not yet proven by the data. There might be a master reaction that induces both processes independently, or there may be influences of other light‐induced processes which lead to enhanced starch breakdown, thereby supplying the glucose for oxidative degradation. 相似文献
62.
Lars?Elkjaer?J?rgensen Marcellus?Ubbink Eva?DanielsenEmail author 《Journal of biological inorganic chemistry》2004,9(1):27-38
To investigate the structural control mechanisms in the metal site of amicyanin when interacting with MADH, redox-inactive Ag+- and Cd2+-substituted amicyanins were studied with perturbed angular correlations of -rays (PAC) spectroscopy. PAC experiments on 111mCd-substituted amicyanin revealed two different metal-site structures, which are very likely in dynamic exchange on a ~5 ns timescale. Only one structure binds to MADH. The dissociation constants, K
d, are 9±2 M with MADHred and 38±11 M with MADHox, indicating that the Cd-amicyanin binding affinity is regulated by the MADH redox state. PAC experiments on 111Ag-substituted amicyanin also showed two different forms of Ag-amicyanin, probably reflecting relaxation from Ag to Cd geometry. No binding of Ag-amicyanin to MADH could be observed with PAC, suggesting that the K
d is larger than 43 M, based on the 95% confidence limit. NMR revealed large chemical shift differences between native copper amicyanin and both metal-substituted forms. Affected residues are found up to 15 Å away from the metal ion. The Ag+- and Cd2+-substituted amicyanins demonstrate no change in coordination as a function of pH, contrary to Cu+-amicyanin which shows protonation of the copper ligand His96 with pK
a=6.8. It is concluded that, contrary to other blue copper proteins, Ag+-amicyanin is not a close mimic of Cu+-amicyanin, and that structural changes in the metal site have large effects on the affinity for the redox partner.Electronic Supplementary Material Supplementary material is available in the online version of this article at
Abbreviations AOM
angular overlap model
- HSQC
heteronuclear single-quantum coherence
- MADH
methylamine dehydrogenase
- MADHox
oxidized MADH
- MADHred
reduced MADH
- NOESY
nuclear Overhauser effect spectroscopy
- NQI
nuclear quadrupole interaction
- PAC
perturbed angular correlations of -rays
- TOCSY
total correlation spectroscopy 相似文献
63.
Activities of NADP-dependent isocitrate dehydrogenases (cytosolic and plastidic isoforms, ICDH1 and ICDH2; EC 1.1.1.42) and ferredoxin-dependent glutamate synthase (Fd-GOGAT; EC 1.4.7.1) in turions of Spirodela polyrhiza were all stimulated by light. Single or repeated red light (R) pulses induced the activity of the enzymes and this effect was reverted by subsequent far-red light (FR) pulses. The enzymes are, therefore, co-regulated by the low-fluence response of phytochrome. For ICDH, this is reported here for the first time. Neither an effect of the very low-fluence response nor of the FR-mediated high-irradiance response was detectable. Irradiance with continuous R resulted in enhanced enzyme activities and protein levels (Western analysis using polyclonal antibodies against ICDH1 and Fd-GOGAT). These additional effects of continuous R (called a non-induction effect) could be inhibited for ICDH1 and ICDH2 by the inhibitor of photosynthetic electron transport, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, and are therefore related to the effect of photosynthesis. In contrast, the non-induction effect of Fd-GOGAT was resistant against this inhibitor. Moreover, hourly R pulses did not replace the effect of continuous R. The non-induction effect of light on the activity and protein level of Fd-GOGAT was therefore tentatively classified as an R-mediated high-irradiance response. The activity of Fd-GOGAT but not that of ICDHs was additionally regulated by a specific blue-light receptor. It can be concluded that the levels of ICDHs and Fd-GOGAT were coordinated by light but were not co-regulated by the same photoreceptors. Nitrate is necessary for the light regulation of both enzymes, contributing to the coordinated expression of the relevant genes.Abbreviations
DCMU
3-(3,4-Dichlorophenyl)-1,1-dimethylurea
-
Fd-GOGAT
Ferredoxin-dependent glutamate synthase
-
FR
Far-red light
-
HIR
High-irradiance response
-
ICDH
NADP-dependent isocitrate dehydrogenase
-
ICDH1
Cytosolic ICDH
-
ICDH2
Chloroplastic ICDH
-
LFR
Low-fluence response
-
R
Red light
-
SDS–PAGE
Denaturing polyacrylamide gel electrophoresis
-
VLFR
Very low-fluence response 相似文献
64.
Blue oat mites, Penthaleus spp. (Acari: Penthaleidae), are major agricultural pests in southern Australia and other parts of the world, attacking various pasture, vegetable and crop plants. Management of these mites has been complicated by the recent discovery of three cryptic pest species of Penthaleus, whereas prior research had assumed a single species. The taxonomy, population genetics, ecology, biology and control of the Penthaleus spp. complex are reviewed. Adult Penthaleus have a dark blue-black body approximately 1 mm in length, and eight red-orange legs. Within Australia, they are winter pests completing two or three generations a season, depending on conditions. The summer is passed as diapausing eggs, when long-distance dispersal is thought to occur. The Penthaleus spp. reproduce by thelytokous parthenogenesis, with populations comprising clones that differ ecologically. The three pest Penthaleus spp. differ markedly in their distributions, plant hosts, timing of diapause egg production and response to pesticides, highlighting the need to develop control strategies that consider each species separately. Chemicals are the main weapons used in current control programs, however research continues into alternative more sustainable management options. Host plant resistance, crop rotations, conservation of natural enemies, and improved timing of pesticide application would improve the management of these pests. The most cost-effective and environmentally acceptable means of control will result from the integration of these practices combined with the development of a simple field-based kit to distinguish the different mite species. 相似文献
65.
Su AK Lin CH 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2003,785(1):39-46
A simple, inexpensive and reliable method for the simultaneous, routine analysis of riboflavin in urine by capillary electrophoresis-light emitting diode (LED)-induced fluorescence detection is described. Using a blue LED as the light source, the detection limit of riboflavin was determined to be 0.48 microg/ml and was improved to 20 ng/ml when a stacking technique was applied. In the analysis of an actual sample, various concentrations of riboflavin were distributed in the urine samples over a period of 9 h after the ingestion of a vitamin B(2) tablet. 相似文献
66.
Moreira PR Almeida-Vara E Sena-Martins G Polónia I Malcata FX Cardoso Duarte J 《Journal of biotechnology》2001,89(2-3):107-111
A novel strain of Bjerkandera sp. (B33/3), with particularly high decolourisation activities upon Poly R-478 and Remazol Brilliant Blue R (RBBR) dyes, was isolated. The role of the ligninolytic extracellular enzymes produced by this strain on decolourisation of RBBR was studied in some depth. The basis of decolourisation is an enzyme-mediated process, in which the main enzyme responsible is a recently described peroxidase with capacity for oxidation of manganese, as well as veratryl alcohol and 2,6-dimethoxyphenol in a manganese-independent reaction. 相似文献
67.
Irradiation of the mitotic (prophase and prometaphase) tissue culture PK (pig kidney embryo) cells using mercury arc lamp and band-pass filters postponed or inhibited anaphase onset. The biological responses observed after irradiation were: (i) normal cell division, (ii) delay in metaphase and then normal anaphase and incomplete cytokinesis, (iii) exit into interphase without separation of chromosomes, (iv) complete mitotic blockage. Cell sensitivity to the light at wavelengths from 423 and 488 nm was nearly the same; to the near UV light (wavelength 360 nm) it was 5–10 times more; to the green light (wavelength >500 nm) it was at least 10 times less. To elucidate the possible mechanism of the action of blue light we measured cell adsorption and examined cell autofluorescence. Autofluorescence of cytoplasmic granules was exited at wavelengths of 450–490 nm, but not at >500 nm. In mitotic cells fluorescent granules accumulated around the spindle. We suppose blue light irradiation induces formation of the free radicals and/or peroxide, and thus perturb the checkpoint system responsible for anaphase onset. 相似文献
68.
《Fungal Ecology》2015
The pine weevil is one of the most important pest insects of conifer reforestation areas in Europe. Female pine weevils cover their eggs with chewed bark and feces (frass) resulting in avoidance behavior of feeding conspecifics towards egg laying sites. It has been suggested that microorganisms present in the frass may be responsible for producing deterrent compounds for the pine weevil. The fungi Ophiostoma canum, O. pluriannulatum, and yeast Debaryomyces hansenii were isolated from aseptically collected pine-weevil frass. The isolated fungi were cultured on weevil frass broth and their volatiles were collected by SPME and identified by GC–MS. D. hansenii produced methyl salicylate (MeS) as a major compound, whereas, in addition, O. canum and O. pluriannulatum produced 6-protoilludene. In a multi-choice lab bioassay, MeS strongly reduced pine weevil's attraction to the Pinus sylvestris volatiles. Thus, a fungal metabolite was found that strongly affects the pine weevil host-odor search. 相似文献
69.
Yoshiaki Hirako Yuki Yonemoto Tomoe Yamauchi Yuji Nishizawa Yoshiyuki Kawamoto Katsushi Owaribe 《Experimental cell research》2014
Hemidesmosomes are cell-to-matrix adhesion complexes anchoring keratinocytes to basement membranes. For the first time, we present a method to prepare a fraction from human cultured cells that are highly enriched in hemidesmosomal proteins. Using DJM-1 cells derived from human squamous cell carcinoma, accumulation of hemidesmosomes was observed when these cells were cultured for more than 10 days in a commercial serum-free medium without supplemental calcium. Electron microscopy demonstrated that numerous electron-dense adhesion structures were present along the basal cell membranes of DJM-1 cells cultured under the aforementioned conditions. After removing cellular materials using an ammonia solution, hemidesmosomal proteins and deposited extracellular matrix were collected and separated by electrophoresis. There were eight major polypeptides, which were determined to be plectin, BP230, BP180, integrin α6 and β4 subunits, and laminin-332 by immunoblotting and mass spectrometry. Therefore, we designated this preparation as a hemidesmosome-rich fraction. This fraction contained laminin-332 exclusively in its unprocessed form, which may account for the promotion of laminin deposition, and minimal amounts of Lutheran blood group protein, a nonhemidesmosomal transmembrane protein. This hemidesmosome-rich fraction would be useful not only for biological research on hemidesmosomes but also for developing a serum test for patients with blistering skin diseases. 相似文献
70.
Domenica Farci Matthew W. Bowler Joanna Kirkpatrick Sean McSweeney Enzo Tramontano Dario Piano 《生物化学与生物物理学报:生物膜》2014
We have analyzed the cell wall of the radio-resistant bacterium Deinococcus radiodurans. Unexpectedly, the bacterial envelope appears to be organized in different complexes of high molecular weight. Each complex is composed of several proteins, most of which are coded by genes of unknown function and the majority are constituents of the inner/outer membrane system. One of the most abundant complexes is constituted by the gene DR_0774. This protein is a type of secretin which is a known subunit of the homo-oligomeric channel that represents the main bulk of the type IV piliation family. Finally, a minor component of the pink envelope consists of several inner-membrane proteins. The implications of these findings are discussed. 相似文献