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To clarify the mechanism of aluminum (Al) toxicity and Al tolerance, we isolated a new clone (pAL201) from a tobacco cDNA library. Northern blot hybridization analysis indicated that the expression of pAL201 is induced by Al treatment and phosphate (P1 ) starvation. The complete cDNA sequence suggested that this clone encodes a moderately anionic peroxidase (EC 1.11.1.7). Analysis by isoelectric focussing indicated that a moderately anionic peroxidase (approximately pI 6.7) and two cationic peroxidases (pI 9.2 and 9.7) in the soluble fraction are activated by Al treatment and P1 starvation, while two moderately anionic isozymes are repressed by these stresses. We suppose that Al ion stress can control the activity of some peroxidase isozymes, one of which is probably induced by enhanced gene expression of pAL201. There is a possibility that some of these isozymes have some functions in Al ion stress. 相似文献
74.
三棱栎群落的区系成分初步研究 总被引:7,自引:3,他引:4
根据三棱区栎群落的野外调查结果,分析了该落的区系成分。热带及亚热带区系成分占很大的比重(占总种数90.25%),其中印度-马来西亚成分占有绝对优势(占41.46%),滇、顷、老、泰、越周边地区的区系成分次之(共占29.27%),与热带非洲有微弱联系,但与热带大洋洲与美洲并无联系。这就在该群落区系成分分析的基础上有力地支持Kevin C.Nixon和William L.Crepet的论点:三棱栎的独 相似文献
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Durosinmi M. A. Ojo J. O. Oluwole A. F. Ononye A. F. Akanle O. A. Spyrou N. M. 《Biological trace element research》1994,(1):357-361
The concentrations of a number of elements are determined in the plasma and erythrocytes of 21 Nigerians (11 females, 10 males)
with symptomatic affective disorders (11 depressives, 10 manics) and in 40 normal controls using proton-induced X-ray emission
(PIXE) analysis. The study shows that there is significant elevation of plasma K and Zn, as well as the erythrocyte S in the
patients relative to the controls. The plasma and erythrocyte Cu, and the erythrocyte P, Ca, Fe, and Zn are significantly
lower in the patients compared to the controls. However, the plasma levels of Ca, S, Fe, and Br are similar in both the patients
and the controls. Similarly, the concentrations of K, Br, and Rb show no significant difference in the erythrocytes of patients
and controls. 相似文献
77.
Study of trace elements in blood of cancer patients by proton-induced X-ray emission (PIXE) analysis
Durosinmi M. A. Ojo J. O. Oluwole A. F. Akanle O. A. Spyrou N. M. 《Biological trace element research》1994,(1):351-355
Proton-induced X-ray emission (PIXE) analysis was employed to determine the concentrations of six elements in the plasma and
erythrocytes of 18 cancer subjects (15 males and 3 females) with neoplastic disorders and in 70 controls (35 males and 35
females). It was found that the concentrations of Br, K, and Zn were significantly elevated in the erythrocytes of the cancer
subjects compared to the controls, whereas the concentration of Fe was significantly depressed, but with no difference observed
in the concentration of Ca. In the plasma, the concentrations of Br, Cu, Ca, and K were significantly elevated, whereas the
concentrations of Fe and Zn were found to be significantly depressed compared to the controls. 相似文献
78.
Fourteen lichens, 10 green algal lichens and four cyanolichens, as well as a cyanobacterium emitted significant quantities of H2S (0.01–0.04 pmol g dw–1 s–1) and DMS (0.005–0.025 pmol g dw–1 s–1) but were sinks for COS (0.015–0.14 pmol g dw–1 s–1). In contrast, exchange of CH3SH and CS2 were sporatic and inconsistent. Although some interspecific variation occurred for the first three gases, exchange rates were relatively uniform and were not influenced by irradiance conditions. In contrast to DMS and H2S emission, COS uptake was strongly influenced by degree of thallus hydration. Because lichen dominated systems cover extensive terrestrial habitats, COS uptake is potentially important in the world's sulfur budget. 相似文献
79.
Abstract: Methylmercury (MeHg) increases the concentration of intracellular Ca2+ ([Ca2+]i) and another endogenous polyvalent cation in both synaptosomes and NG108-15 cells. In synaptosomes, the elevation in [Ca2+]i was strictly dependent on extracellular Ca2+ (Ca2+e); similarly, in NG108-15 cells, a component of the elevations in [Ca2+]i was Ca2+e dependent. The MeHg-induced elevations in endogenous polyvalent cation concentration were independent of Ca2+e in synaptosomes and NG108-15 cells. The pattern of alterations in fura-2 fluorescence suggested the endogenous polyvalent cation may be Zn2+. Using 19F-NMR spectroscopy of rat cortical synaptosomes loaded with the fluorinated chelator 1,2-bis(2-amino-5-fluorophenoxy)ethane-N,N,N′,N′-tetraacetic acid (5F-BAPTA), we have determined unambiguously that MeHg increases the free intrasynaptosomal Zn2+ concentration ([Zn2+]i). In buffer containing 200 µM EGTA to prevent the Ca2+e-dependent elevations in [Ca2+]i, the [Zn2+]i was 1.37 ± 0.20 nM; following a 40-min exposure to MeHg-free buffer [Zn2+]i was 1.88 ± 0.53 nM. Treatment of synaptosomes for 40 min with 125 µM MeHg yielded [Zn2+]i of 2.69 ± 0.55 nM, whereas 250 µM MeHg significantly elevated [Zn2+]i to 3.99 ± 0.68 nM. No Zn2+ peak was observed in synaptosomes treated with the cell-permeant heavy metal chelator N,N,N′,N′-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN, 100 µM) following 250 µM MeHg exposure. [Ca2+]i in buffer containing 200 µM EGTA was 338 ± 26 nM and was 370 ± 64 nM following an additional 40-min exposure to MeHg-free buffer. [Ca2+]i was 498 ± 28 or 492 ± 53 nM during a 40-min exposure to 125 or 250 µM MeHg, respectively. None of the values of [Ca2+]i differed significantly from either pretreatment levels or buffer-treated controls. 相似文献
80.
A growth analysis was made of ultraviolet-B (UV-B)-sensitive (Poinsett) and insensitive (Ashley) cultivars of Cucuumis satives L. grown in growth chambers at 600 μmol m−2 s−1 of photosynthetic photon flux (PPF) provided by red- and far-red-deficient metal halide (MH) or blue- and UV-A-deficient high pressure sodium/deluxe f HPS/DX) lamps. Plants were irradiated 6 h daiiy with 0.2 f-UV-B) or 18.2 C+UV-B) kJ m−2 day−1 of biologically effective UV-B for 8 or 15 days from time of seeding. In general, plants given supplemental UV-B for 15 days showed lower leaf area ratio (LARs, and higher specific leaf mass (SLM) mean relative growth rate (MRGR) and net assimilation rate (NAR) than that of control plants, but they showed no difference in leaf mass ratio (LMR), Plants grown under HPS/DX lamps vs MH lamps showed higher SLM and NAR. lower LAR and LMR. hut no difference in MRGR. LMR was the only growth parameter affected by cultivar: at 15 days, it was slightly greater in Poinsett than in Ashley. There were no interactive effects of UV-B. PPF source or cultivar on any of the growth parameters determined, indicating that the choice of either HPS/DX or MH lamps should not affect growth response to UV-B radiation. This was true even though leaves of UV-B-irradiated plants grown under HPS/DX lamps have been shown to have greater chlorosis than those grown under MH lamps. 相似文献