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1.
Relationship between tolerance and accumulation characteristics of cadmium in higher plants 总被引:3,自引:0,他引:3
Ten plant species belonging to 5 families,i.e., Cruciferae, Cucurbitaceae, Gramineae, Leguminosae, and Solanaceae, were grown in a sand soil at two pH levels. The soil
was subjected to an application of CdCl2 at rates of 0 to 700 mgCd·kg−1 soil. The relationship between Cd concentration in the shoots (tc) and soil (sc; NH4NO3 extractable) was expressed by the equation: log (tc)=α+βlog (sc). The coefficients α and β were estimated for each species at each level of soil pH. Plottings of the scores on α and β axes
showed that the Cd accumulation characteristics in the plants appeared to depend on the families irrespective of soil pH.
Based on theupper critical concentration of Cd in the tops (Ct), the Cruciferae and Leguminosae species were found to be the most and the least tolerant to Cd, respectively. The Ct values correlated exceedingly well with the values of α. 相似文献
2.
Vidushi S Patel Steven JB Cooper Janine E Deakin Bob Fulton Tina Graves Wesley C Warren Richard K Wilson Jennifer AM Graves 《BMC biology》2008,6(1):34
Background
Vertebrate alpha (α)- and beta (β)-globin gene families exemplify the way in which genomes evolve to produce functional complexity. From tandem duplication of a single globin locus, the α- and β-globin clusters expanded, and then were separated onto different chromosomes. The previous finding of a fossil β-globin gene (ω) in the marsupial α-cluster, however, suggested that duplication of the α-β cluster onto two chromosomes, followed by lineage-specific gene loss and duplication, produced paralogous α- and β-globin clusters in birds and mammals. Here we analyse genomic data from an egg-laying monotreme mammal, the platypus (Ornithorhynchus anatinus), to explore haemoglobin evolution at the stem of the mammalian radiation. 相似文献3.
T. V. Malyarenko A. A. Kicha N. V. Ivanchina A. I. Kalinovsky P. S. Dmitrenok A. V. Smirnov 《Russian Journal of Bioorganic Chemistry》2010,36(6):755-761
Thirteen steroidal compounds including three new polyhydroxysteroids, (24R,25S)-24-methyl-5α-cholestane-3β,6α,8,15β,16β,26-hexaol, (22E,24R,25S)-24-methyl-5α-cholest-22-ene-3β,6α,8,15β,16β,26-hexaol, and (22E,24R,25S)-24-methyl-5α-cholest-22-ene-3β,4β,6α,8,15β,16β,26-heptaol, have been isolated along with ten previously known polyhydroxysteroids
from the tropical starfish Asteropsis carinifera collected near the coast of Vietnam. The structures of the new compounds were elucidated by spectroscopic methods (mainly
2D NMR and ESI mass spectrometry). 相似文献
4.
E. V. Levina D. L. Aminin S. N. Kovalchuk V. B. Kozhemyako S. A. Dyshlovoi A. I. Kalinovskii P. S. Dmitrenok 《Russian Journal of Bioorganic Chemistry》2010,36(2):233-239
Four polyhydroxylated steroids, new (20R)-5α-cholestan-3β,6α,8,15α,24,26-hexaol (I) and known (20R,25S)-5α-cholestan-3β,6α,8,15β,16β,26-hexaol, (20R,25S)-5α-cholestan-3β,6α,15β,16β,26-pentaol, and marthasterone sulfate were isolated from the Solaster endeca starfish inhabiting the Sea of Okhotsk and characterized. Steroid (I) contains a 24,26-dihydroxylated side chain, which is unique for starfish polyols. The isolated steroids and related metabolites
from two starfish species of the Evasterias genus (in total, 15 compounds) were weakly cytotoxic in a human HeLa cell culture and some of them were inhibitors of non-specific
esterase from mouse Ehrlich carcinoma. The effects of these compounds on the p53 protein activity were studied in a yeast
two-hybrid test system and both inhibitors and stimulators of this activity were found among them. 相似文献
5.
Seven analogues of p-nitrophenyl T-antigen [Galβ(1→3)GalNAcα(1→O)PNP] have been synthesized as potential substrates for elucidation of the substrate specificity of endo-α-N-acetylgalactosaminidase. These compounds, which are commercially unavailable, include: GlcNAcβ(1→3){GlcNAcβ(1→6)}GalNAcα(1→O)PNP [core 4 type], GalNAcα(1→3)GalNAcα(1→O)PNP [core 5 type], GlcNAcβ(1→6)GalNAcα(1→O)PNP [core 6 type], GalNAcα(1→6)GalNAcα(1→O)PNP [core 7 type], Galα(1→3)GalNAcα(1→O)PNP [core 8 type], Glcβ(1→3)GalNAcα(1→O)PNP and GalNAcβ(1→3)GalNAcα(1→O)PNP. The assembly of these synthetic probes was accomplished efficiently, based on di-tert-butylsilylene(DTBS)-directed α-galactosylation as a key reaction. 相似文献
6.
The amino acid sequences of 22 α-amylases from family 13 of glycosyl hydrolases were analyzed with the aim of revealing the
evolutionary relationships between the archaeal α-amylases and their eubacterial and eukaryotic counterparts. Two evolutionary
distance trees were constructed: (i) the first one based on the alignment of extracted best-conserved sequence regions (58
residues) comprising β2, β3, β4, β5, β7, and β8 strand segments of the catalytic (α/β)8-barrel and a short conserved stretch in domain B protruding out of the barrel in the β3 →α3 loop, and (ii) the second one
based on the alignment of the substantial continuous part of the (α/β)8-barrel involving the entire domain B (consensus length: 386 residues). With regard to archaeal α-amylases, both trees compared
brought, in fact, the same results; i.e., all family 13 α-amylases from domain Archaea were clustered with barley pI isozymes,
which represent all plant α-amylases. The enzymes from Bacillus licheniformis and Escherichia coli, representing liquefying and cytoplasmic α-amylases, respectively, seem to be the further closest relatives to archaeal α-amylases.
This evolutionary relatedness clearly reflects the discussed similarities in the amino acid sequences of these α-amylases,
especially in the best-conserved sequence regions. Since the results for α-amylases belonging to all three domains (Eucarya,
Eubacteria, Archaea) offered by both evolutionary trees are very similar, it is proposed that the investigated conserved sequence
regions may indeed constitute the ``sequence fingerprints' of a given α-amylase.
Received: 3 June 1998 / Accepted: 20 August 1998 相似文献
7.
8.
Hisashi Kato-Noguchi Madoka Yamamoto Kazuya Tamura Toshiaki Teruya Kiyotake Suenaga Yoshiharu Fujii 《Plant Growth Regulation》2010,60(2):127-131
Aqueous methanol extracts of rattail fescue (Vulpia myuros) inhibited the growth of roots and shoots of cress (Lepidium sativum), lettuce (Lactuca sativa), alfalfa (Medicago sativa), timothy (Phleum pratense), Digitaria sanguinalis and Lolium multiflorum. Increasing the extract concentration increased the inhibition, suggesting that rattail fescue may have growth inhibitory
substances and possess allelopathic potential. The aqueous methanol extract of rattail fescue was purified and two main inhibitory
substances were isolated and identified by spectral data as (−)-3-hydroxy-β-ionone and (+)-3-oxo-α-ionol. Both substances
inhibited root and shoot growth of cress at concentrations greater than 0.3 μM. The concentrations required for 50% growth
inhibition on root and shoot growth of cress, lettuce, alfalfa, timothy, D. sanguinalis and L. multiflorum were 2.7–19.7 μM for (−)-3-hydroxy-β-ionone, and 2.1–34.5 μM for (+)-3-oxo-α-ionol. The concentration of (−)-3-hydroxy-β-ionone
and (+)-3-oxo-α-ionol, respectively, in rattail fescue was 7.8 and 3.7 μg g−1 fresh weight. Considering the endogenous level and the inhibitory activity, (−)-3-hydroxy-β-ionone and (+)-3-oxo-α-ionol
may work as allelopathic substances in rattail fescue through the growth inhibition of neighboring plant species. 相似文献
9.
P2X1 receptors, the major subtype of P2X receptors in the vascular smooth muscle, are essential for α,β-methylene adenosine 5′-triphosphate
(α,β-MeATP)-induced vasoconstriction. However, relative physiological significance of P2X1 receptor-regulated vasoconstriction in the different types of arteries in the rat is not clear as compared with α1-adrenoceptor-regulated vasoconstriction. In the present study, we found that vasoconstrictive responses to noncumulative
administration of α,β-MeATP in the rat isolated mesenteric arteries were significantly smaller than those to single concentration
administration of α,β-MeATP. Therefore, we firstly reported the characteristic of α,β-MeATP-regulated vasoconstrictions in
rat tail, internal carotid, pulmonary, mesenteric arteries, and aorta using single concentration administration of α,β-MeATP.
The rank order of maximal vasoconstrictions for α,β-MeATP (E
max·α,β-MeATP) was the same as that of maximal vasoconstrictions for noradrenaline (E
max·NA) in the internal carotid, pulmonary, mesenteric arteries, and aorta. Moreover, the value of (E
max·α,β-MeATP/E
max·KCl)/(E
max·NA/E
max·KCl) was 0.4 in each of the four arteries, but it was 0.8 in the tail artery. In conclusion, P2X1 receptor-mediated vasoconstrictions are equally important in rat internal carotid, pulmonary, mesenteric arteries, and aorta,
but much greater in the tail artery, suggesting its special role in physiological function. 相似文献
10.
11.
Evolution of the Integrin α and β Protein Families 总被引:4,自引:0,他引:4
Hughes AL 《Journal of molecular evolution》2001,52(1):63-72
A phylogenetic analysis of vertebrate and invertebrate α integrins supported the hypothesis that two major families of vertebrate
α integrins originated prior to the divergence of deuterostomes and protostomes. These two families include, respectively,
the αPS1 and αPS2 integrins of Drosophila melanogaster, and each family has duplicated repeatedly in vertebrates but not in Drosophila. In contrast, a third family (including αPS3) has duplicated in Drosophila but is absent from vertebrates. Vertebrate αPS1 and αPS2 family members are found on human chromosomes 2, 12, and 17. Linkage
of these family members may have been conserved since prior to the origin of vertebrates, and the two genes duplicated simultaneously.
A phylogenetic analysis of β integrins did not clearly resolve whether vertebrate β integrin genes duplicated prior to the
origin of vertebrates, although it suggested that at least the gene encoding vertebrate β4 may have done so. In general, the
phylogeny of neither α nor β integrins showed a close correspondence with patterns of α–β heterodimer formation or other functional
characteristics. One major exception to this trend involved αL, αM, αX, and αD, a monophyletic group of immune cell-expressed
α integrins, which share a number of common functional characteristics and have evolved in coordinated fashion with their
β integrin partners.
Received: 22 June 2000 / Accepted: 11 September 2000 相似文献
12.
Lee S Jia B Pham BP Shao Y Kwak JM Cheong GW 《Extremophiles : life under extreme conditions》2012,16(1):87-93
Sarcosine oxidase (SOX) catalyzes the oxidation of the methyl group in sarcosine and transfer of the oxidized methyl group
into the one-carbon metabolic pool. Here, we separately cloned and expressed α and β subunit of SOX from Thermococcus kodakarensis KOD1 (TkSOX) in Escherichia coli and the recombinant proteins were purified to homogeneity. Gel filtration chromatography and transmission electron microscopy
analysis showed that the α subunit formed a dimeric structure and behaved as an NADH dehydrogenase; β subunit was a tetramer
that had sarcosine oxidase and l-proline dehydrogenase activity. The TkSOX complex assembled into the hetero-octameric (αβ)4 form and had NADH dehydrogenase activity. Gold-label analysis indicated that α and β subunits were oriented in the alternative
form. Based on these results, we suggested that TkSOX was a multifunctional enzyme and that each subunit and (αβ)4 complex may separately exist as a function enzyme in different conditions. 相似文献
13.
I. Stancheva M. Geneva M. Hristozkova Y. Markovska I. Salamon 《Russian Journal of Plant Physiology》2010,57(6):799-805
Oxidative stress response and essential oil composition of sage (Salvia officinalis L.), grown on industrially polluted soil were studied. Sage plants were grown on the soil polluted with Cd, Cu, Pb, Zn, and
non-polluted control soil. One-year-old sage possessed a high potential for heavy metal accumulation mainly in the roots.
Heavy metal pollution resulted in root and shoot dry biomass inhibition. The increased levels of hydrogen peroxide and MDA
showed that the heavy metal uptake caused oxidative stress. The increase towards the control was observed in the levels of
glutathione, ascorbate, dehydroascorbate, catalase, dehydroascorbate reductase, and glutathione peroxidase. Weak activities
of the most enzymes of the ascorbate-glutathione cycle allowed to suppose that H2O2 neutralization is rather non-enzymatic than enzymatic process. Observed decline in α- and β-thujones and elevated camphor
content in the sage leaves did not indicate a deterioration of the essential oil quality. Sage grown on heavy metal-polluted
soil successfully accumulated cadmium, lead, and zinc, which is resulted in plant biomass inhibition, but essential oil yield
and quality was not declined. 相似文献
14.
Changes in α- and β-galactosidase, glucosidase, and α-mannosidase and β-xylosidase activities were analyzed in developing
mustard (Brassica juncea) seed. A cubic polynomial described the seed dry weight data adequately. A close parallelism between the water content and
dry matter accumulation was shown (r= 0.991). Glycosidase activities were detected in both cytoplasmic and wall fractions. The trend was similar in both of the
fractions, but the activity of α-mannosidase and α-galactosidase was considerably greater in the wall-bound fraction. The
water content and the activity of glycosidic enzymes showed a significant linear correlation (p < 0.001). The results suggest that glycosidases have an important role in cell wall loosening during mustard seed development.
Received July 10, 1997; accepted January 28, 1998 相似文献
15.
16.
D. Vidović N. Boulanger Olabisi Kuye Joyce Toral Kouichi Ito Jeanmarie Guenot Horst Bluethmann Zoltan A. Nagy 《Immunogenetics》1997,45(5):325-335
Mutant mice generated by disrupting the H2-Aa
b
major histocompatibility complex (Mhc) gene are demonstrated here to express Aβb chains in the absence of α chains. These mice possess a CD4+ helper T cell (Th) repertoire that uses predominantly the Vβ7 T-cell antigen receptor (Tcr) segment for recognition of any
protein antigen presented by the α-free Aβ molecule. As an alloantigen, the Aα-free Aβ molecule is recognized very poorly
by T cells from a series of class II disparate mouse strains, indicating that it is grossly different from normal α/β heterodimers.
Indeed, molecular modeling suggests a β/β homodimer arrangement with an altered geometry of the Tcr contact area. Interestingly,
the mutant mice exhibit normal alloreactivity, without a restricted Vβ usage, toward a series of foreign α/β class II heterodimers,
although their T cells developed in the absence of such heterodimers. Thus, the complementarity of Tcr to normal α/β heterodimers,
and thereby also alloreactivity, appears to be an ontogeny independent (i. e., germline-encoded) feature.
Received: 30 September 1996 / Revised: 18 October 1996 相似文献
17.
Jones AK Marshall J Blake AD Buckingham SD Darlison MG Sattelle DB 《Invertebrate neuroscience : IN》2005,5(3-4):147-155
The cloning, sequencing and functional expression of Sgβ1, a novel locust (Schistocerca gregaria) non-α nicotinic acetylcholine receptor (nAChR) subunit is described. This subunit shows 80% identity with the Drosophila melanogaster Dβ1 and 92% identity with the Locusta migratoria β1, non-α subunits but only 38% identity to Sgα1 (also referred to as αL1), a previously cloned S. gregaria nAChR α-subunit. When expressed in Xenopus laevis oocytes, Sgβ1 does not respond to nicotine. Responses to nicotine are observed, however, in oocytes co-expressing Sgα1 and Sgβ1, but the pharmacology is indistinguishable from that of currents produced by expressing Sgα1 alone. We conclude that either Sgβ1 does not co-assemble with Sgα1, or that it is unable to contribute to the functional properties of the receptor, in the Xenopus oocyte expression system. 相似文献
18.
Fengshan Pan Qian Meng Sha Luo Jing Shen Bao Chen Kiran Yasmin Khan 《International journal of phytoremediation》2017,19(3):281-289
Four plant growth-promoting bacteria (PGPB) were used as study materials, among them two heavy metal-tolerant rhizosphere strains SrN1 (Arthrobacter sp.) and SrN9 (Bacillus altitudinis) were isolated from rhizosphere soil, while two endophytic strains SaN1 (Bacillus megaterium) and SaMR12 (Sphingomonas) were identified from roots of the cadmium (Cd)/zinc (Zn) hyperaccumulator Sedum alfredii Hance. A pot experiment was carried out to investigate the effects of these PGPB on plant growth and Cd accumulation of oilseed rape (Brassica napus) plants grown on aged Cd-spiked soil. The results showed that the four PGPB significantly boosted oilseed rape shoot biomass production, improved soil and plant analyzer development (SPAD) value, enhanced Cd uptake of plant and Cd translocation to the leaves. By fluorescent in situ hybridization (FISH) and green fluorescent protein (GFP), we demonstrated the studied S. alfredii endophytic bacterium SaMR12 were able to colonize successfully in the B. napus roots. However, all four PGPB could increase seed Cd accumulation. Due to its potential to enhance Cd uptake by the plant and to restrict Cd accumulation in the seeds, SaMR12 was selected as the most promising microbial partner of B. napus when setting up a plant–microbe fortified remediation system. 相似文献
19.
20.
Thomas A. Gorr Barbara K. Mable Traute Kleinschmidt 《Journal of molecular evolution》1998,47(4):471-485
Phylogenetic relationships among reptiles were examined using previously published and newly determined hemoglobin sequences.
Trees reconstructed from these sequences using maximum-parsimony, neighbor-joining, and maximum-likelihood algorithms were
compared with a phylogenetic tree of Amniota, which was assembled on the basis of published morphological data. All analyses differentiated α chains into αA and αD types, which are present in all reptiles except crocodiles, where only αA chains are expressed. The occurrence of the αD chain in squamates (lizards and snakes only in this study) appears to be a general characteristic of these species. Lizards
and snakes also express two types of β chains (βI and βII), while only one type of β chain is present in birds and crocodiles.
Reconstructed hemoglobin trees for both α and β sequences did not yield the monophyletic Archosauria (i.e., crocodilians + birds) and Lepidosauria (i.e., Sphenodon+ squamates) groups defined by the morphology tree. This discrepancy, as well as some other poorly resolved nodes, might be
due to substantial heterogeneity in evolutionary rates among single hemoglobin lineages. Estimation of branch lengths based
on uncorrected amino acid substitutions and on distances corrected for multiple substitutions (PAM distances) revealed that
relative rates for squamate αA and αD chains and crocodilian β chains are at least twice as high as those of the rest of the chains considered. In contrast to
these rate inequalities between reptilian orders, little variation was found within squamates, which allowed determination
of absolute evolutionary rates for this subset of hemoglobins. Rate estimates for hemoglobins of lizards and snakes yielded
1.7 (αA) and 3.3 (β) million years/PAM when calibrated with published divergence time vs. PAM distance correlates for several speciation
events within snakes and for the squamate ↔ sphenodontid split. This suggests that hemoglobin chains of squamate reptiles
evolved ∼3.5 (αA) or ∼1.7 times (β) faster than their mammalian equivalents. These data also were used to obtain a first estimate of some
intrasquamate divergence times.
Received: 15 September 1997 / Accepted: 4 February 1998 相似文献