Constitutive Expression of α-galactosidase Mel1 Gene in Pichia pastoris

用PCR方法从酵母(Saccharomyces cerevisiae ) AH109中扩增出α-半乳糖苷酶的Mel1基因，将其克隆至整合型载体pGAPZαA中构建成组成型分泌表达酶产物的重组质粒pGAPZα-Mel1。将线性化的重组质粒pGAPZα-Mel1电击转化至毕赤酵母(Pichia pastoris ) KM71，在含有100 mg/mL zeocin和预先涂布有X-α-gal的YPDS平板上选择蓝色阳性菌落。发酵培养酵母的上清经SDS-PAGE分析，在53 kD处有特异带；经非变性PAGE凝胶电泳，与显色底物的反应，检测到α-半乳糖苷酶活性带。重组菌pGAPZα-Mel1 /KM71摇瓶发酵6 d后，培养液α-半乳糖苷酶粗酶活性为12 U/mL。     

Organics Wastewater Degradation by a Mesoporous Chromium-Functionalized γ-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> with H<Subscript>2</Subscript>O<Subscript>2</Subscript> Assistance

In this study, a mesoporous chromium-functionalized γ-Al₂O₃ (Cr/γ-Al₂O₃) catalyst was prepared by an impregnation method, and the catalytic activity was evaluated by the degradation of organics wastewater. The prepared catalyst was characterized by X-ray photoelectron spectroscopy, X-ray diffraction, nitrogen adsorption-desorption experiments, and scanning electron microscopy. The characterization results confirmed that the pores in the Cr/γ-Al₂O₃ catalyst distributed broadly in the mesoporous region, and the active chromium species were highly dispersed on the catalyst surface. The catalytic activity tests showed that the Cr/γ-Al₂O₃ catalyst exhibited a superior performance for the degradation of organics wastewater with H₂O₂ assistance. And the methylene blue (MB) disappeared within 20 min and the COD removal reached 76.5% within 40 min for the MB-simulated wastewater; for the phenol-simulated wastewater, the phenol removal was above 95% and the corresponding COD removal reached 71% within 40 min. Such an excellent catalytic performance demonstrates that the Cr/γ-Al₂O₃ catalyst has a potential application in the degradation of complex organics wastewater simultaneously.     

Temporal in situ dynamics of N<Subscript>2</Subscript>O reductase activity as affected by nitrogen fertilization and implications for the N<Subscript>2</Subscript>O/(N<Subscript>2</Subscript>O + N<Subscript>2</Subscript>) product ratio and N<Subscript>2</Subscript>O mitigation

In vitro, high nitrate (NO₃ ^?) concentrations significantly inhibit N₂O reductase activity. However, little information is available on the in situ temporal effects of excessive N fertilization on soil N₂O reductase activity and the regulation of the N₂O/(N₂ + N₂O) product ratio in agricultural soil. This study examined the monthly in situ dynamics of NO₃ ^? concentration, N₂O reductase activity, and N₂O/(N₂ + N₂O) product ratio for 2 years in loamy soil that had received either continuous N fertilizer at 400 kg N ha^?1 year^?1 for 15 years (N400) or no N fertilizers (CK). N₂O reductase activity was significantly lower under the N400 treatment than under the CK and correlated negatively with soil NO₃ ^? concentration. The decrease in N₂O reductase activity resulted in the N₂O/(N₂ + N₂O) product ratio increasing. These results demonstrate that excessive N fertilization has the potential to increase N₂O emissions by reducing N₂O reductase activity in soils. These results highlight the need for N₂O mitigation options to embrace the reduction of soil NO₃ ^? concentrations.     

Effect of Co-Dopants in TiO<Subscript>2</Subscript>–SiO<Subscript>2</Subscript> Thin films on the Formaldehyde Degradation

Titanium dioxide (TiO₂)–silicon dioxide (SiO₂) thin films were synthesized using the peroxo titanic acid approach (PTA) combined with the sol–gel method at low temperature around 100°C. The effects of type and amount of dopants of ferric (Fe³⁺) or thiourea (N-S) and co-dopants of Fe³⁺ and N-S on the films physicochemical properties and on the photocatalytic degradation of the methylene blue and formaldehyde under UV and visible light irradiation were investigated. Physicochemical properties of photocatalysts were characterized by X-ray diffraction, transmission electron microscopy, wavelength-dispersive X-ray fluorescence spectrometry, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and UV–Vis spectroscopy. The results showed that the TiO₂ crystal phases obtained from this method were exclusively anatase and the needle-like crystals have an average diameter of 10–25 nm. Compared with the single dopant of 1.0 wt.% Fe³⁺ or 0.125 wt.% N-S that was the optimal concentration for photocatalytic degradation of methylene blue and formaldehyde, the co-dopants of 0.125 wt.% N-S + 1.0 wt.% Fe³⁺ furthermore increased the degradation efficiency. Co-dopants of 0.125 wt.% N-S + 1.0 wt.% Fe³⁺ in TiO₂–SiO₂ films were considered to play synergistic roles in narrowing TiO₂ band gap resulting in the higher methylene blue and formaldehyde degradation efficiency. Since the crystal grain size of TiO₂–SiO₂ films synthesized by the PTA method is small, in the visible light region, the high transmittance was attainable to 80% with no-doped and dropped to 50–60% with doped thin films.     

Heterotrophic nitrification is the predominant NO<Stack><Subscript>3</Subscript><Superscript>−</Superscript></Stack> production mechanism in coniferous but not broad-leaf acid forest soil in subtropical China

A study was carried out to investigate the potential gross nitrogen (N) transformations in natural secondary coniferous and evergreen broad-leaf forest soils in subtropical China. The simultaneously occurring gross N transformations in soil were quantified by a ¹⁵N tracing study. The results showed that N dynamics were dominated by NH₄⁺ turnover in both soils. The total mineralization (from labile and recalcitrant organic N) in the broad-leaf forest was more than twice the rate in the coniferous forest soil. The total rate of mineral N production (NH₄⁺ + NO₃⁻) from the large recalcitrant organic N pool was similar in the two forest soils. However, appreciable NO₃⁻ production was only observed in the coniferous forest soil due to heterotrophic nitrification (i.e. direct oxidation of organic N to NO₃⁻), whereas nitrification in broad-leaf forest was little (or negligible). Thus, a distinct shift occurred from predominantly NH₄⁺ production in the broad-leaf forest soil to a balanced production of NH₄⁺ and NO₃⁻ in the coniferous forest soil. This may be a mechanism to ensure an adequate supply of available mineral N in the coniferous forest soil and most likely reflects differences in microbial community patterns (possibly saprophytic, fungal, activities in coniferous soils). We show for the first time that the high nitrification rate in these soils may be of heterotrophic rather than autotrophic nature. Furthermore, high NO₃⁻ production was only apparent in the coniferous but not in broad-leaf forest soil. This highlights the association of vegetation type with the size and the activity of the SOM pools that ultimately determines whether only NH₄⁺ or also a high NO₃⁻ turnover is present.     

A simulation model of <Superscript>90</Superscript>Sr daily dynamics in the <Emphasis Type="Italic">soil</Emphasis>–<Emphasis Type="Italic">stand</Emphasis> system of deciduous forests

A simulation model of the ⁹⁰Sr dynamics in the soil and stand components of deciduous forest ecosystems with a 1-day step was developed; this model was used to conduct numerical experiments to clarify the mechanisms of the ⁹⁰Sr behavior. The algorithm allows one to take into account the effect of meteorological, phenological, and physiological factors on the behavior of the radionuclide and simulate different fallout conditions. The results of simulation can be used in the valuation of deciduous forest products. The model is applicable for studying the redistribution of calcium in the stand of deciduous forest ecosystems.     

Comparative Photocatalytic Performance on the Degradation of 2-Naphthol Under Simulated Solar Light Using α-Bi<Subscript>4</Subscript>V<Subscript>2</Subscript>O<Subscript>11</Subscript> Synthesized by Solid-State and Co-precipitation Methods

In this investigation, the photocatalytic activity of α-Bi₄V₂O₁₁ in the degradation of 2-naphthol under simulated solar light was evaluated. Bismuth vanadate α-Bi₄V₂O₁₁ was synthesized by the solid-state reaction method and by co-precipitation in aqueous media, with the aim of comparing their performance in the photodegradation of the aromatic pollutant. The latter method (co-precipitation) has not been previously reported for the synthesis of α-Bi₄V₂O₁₁. Structural evolution of the oxides precursors was determined by X-ray diffraction. Morphology and optical properties of the solids were analyzed by scanning electron microscopy (SEM) and UV-vis diffuse reflectance spectroscopy (UV-vis), respectively. The results showed that at 800 °C, only α-Bi₄V₂O₁₁ was formed in both preparations. The SEM micrographs revealed that the powders were composed of agglomerates with sizes between 0.8–2 μm for those synthesized by co-precipitation and 2–10 μm for those obtained by solid-state reaction. The optical properties indicated that α-Bi₄V₂O₁₁ was activated with visible light during the photocatalytic process. The photocatalytic degradation of 2-naphthol was largely influenced at basic pH, degrading 79% of the contaminant in 240 min, with the powder obtained by co-precipitation; meanwhile, for the solid-state preparation, the degradation reached only 55%.     

Genetic Erosion – Examples from Italy<Superscript>1,2</Superscript>

Italy has been used as a country for estimating genetic erosion in crops. It was possible to compare early surveys (from the 1920s to the 1950s), especially on wheats, with results of later missions in the 1980s and 1990s. In the early years, a relatively high genetic erosion was observed (13.2% p.a.). From the 1950s until the 1980s erosion rates between 0.48 and 4% p.a. were estimated. In the little island of Favignana there was an erosion rate of 12.2% p.a. leading to the extinction of the last wheat landraces of this island. There have been no significant differences in erosion rates between field- and garden-crops though there has been the impression that garden crops are better preserved over the long run. Interestingly extinction rates of wild plants (0.13% in the Mediterranean) come close to the average erosion rates of crop plants in the area. ¹Dedicated to Erna Bennett on the occasion of her 80^th birthday ²Lecture presented during the XVII^th Congress of EUCARPIA in Tulln, Austria, 2004     

Are <Emphasis Type="Italic">Melilotus albus</Emphasis> and <Emphasis Type="Italic">M. officinalis</Emphasis> conspecific?

The principal economic species of the genus Melilotus are white sweet-clover (Melilotus albus) and the extremely similar yellow sweet-clover (M. officinalis). Although they are widely recognized as distinct species, some influential references in North America reduce the former to a subspecific rank or even merely a conspecific synonym of the latter. Given their importance and the large numbers of germplasm collections, the doubt needs to be resolved. This review of relevant published evidence finds that in addition to the difference in floral colour, the traditional segregation of the two as distinct species is best supported by very strong reproductive barriers as well as divergent DNA sequences in three barcoding genes. Additional but weaker confirmation of separateness is provided by studies reporting differences in external morphology, biochemistry, seed protein profiles, karyotype and DNA microsatellites.     

Evaluation of Magnetic Coagulant (α-Fe<Subscript>2</Subscript>O<Subscript>3</Subscript>-MO) and its Reuse in Textile Wastewater Treatment

The textile industries are characterized as one of the biggest consumers of potable water and chemical products throughout its process, being responsible for the elevated wastewater generation with intense coloration and wide polluting potential. In this context, the present study proposes the development and application of a new coagulant material for textile wastewater treatment. The proposed coagulant (α-Fe₂O₃-MO) was composed by hematite nanoparticles (α-Fe₂O₃) obtained by a simple non-pollutant methodology, associated with Moringa oleifera (MO) seeds saline extract compounds. Coagulation/flocculation (CF) efficiency was evaluated by removal of physicochemical parameters such as apparent color, turbidity, and compounds with absorption at UV_254nm (UV_254nm) through CF tests carried out on Jar test equipment and sedimentation carried out in the presence and absence of external magnetic field (600 k Am^?1). Kinetics sedimentation was from 0 to 90 min. The use of this new coagulant allowed the removal of 92.37% for apparent color, 91.43% for turbidity, and 46.09% for UV_254nm, indicating that the proposed coagulant association was efficient in the treatment of this type of wastewater under external magnetic field with only 10 min of sedimentation. In addition, the resulting sludge from CF process was tested as base material for a new coagulant synthesis, demonstrating great reuse potential. Therefore, the new proposed coagulant, composed of α-Fe₂O₃ and the compounds present in the seed extract of MO, has applicability for textile wastewater treatment demonstrating high removal rate for all evaluated parameters with cost reduction in the proposed treatment for this wastewater.     

<Emphasis Type="Italic">Arnica montana</Emphasis> subsp. <Emphasis Type="Italic">atlantica</Emphasis>: Really a subspecies?

In Arnica montana L. (Asteraceae) two subspecies are described, A. montana subsp. atlantica (AMA), present only on the Iberian Peninsula and A. montana subsp. montana (AMM) with a very wide distribution area. The morphological differences between the two subspecies are small and variable. Therefore, this concept is sometimes questioned. To establish the genetic background of the two subspecies, populations of AMA and AMM together with herbarium samples and DNA Bank material of AMM were tested with 12 microsatellite markers. A. montana propagates by seeds or by clonal propagation of its rhizome. In AMA, clonality was frequent while in AMM only one case of clonality could be identified. Therefore, further results were clone-corrected. Genetically, AMA separated very well from AMM with a G_ST between the subspecies of 0.81, genetically justifying the subspecies concept of A. montana. Genetic variability in AMA (H_exp?=?0.28) was lower than in the AMM populations (H_exp?=?0.70). A somewhat higher fixation index of AMA (F_ST?=?0.17, compared to an F_ST?=?0.08 for AMM) may indicate that geneflow in AMA is a bit more restricted than in alpine AMM. However, the fixation index of AMA is not deviating from Hardy–Weinberg equilibrium. No inbreeding was observed for AMA (F_IS?=?0.10) and AMM (F_IS?=?0.08).     

Adaptive values of wild × cultivated sorghum (<Emphasis Type="Italic">Sorghum bicolor</Emphasis> (L.) Moench) hybrids in generations F<Subscript>1</Subscript>, F<Subscript>2</Subscript>, and F<Subscript>3</Subscript>

Gene flow between cultivated and their wild relatives is one of the main ecological concerns associated with the introduction genetically modified (GM) cultivars. GM sorghum cultivar has been developed and its commercial production may be possible in the near future. The rate of gene flow depends on the fitness of wild × cultivated sorghum hybrids. The study aimed at estimating adaptive values of wild × cultivated sorghum hybrids in generations F₁, F₂, and F₃ compared to their parents. Artificial crosses of four wild sorghums, five cultivated sorghums, and two male sterile lines were made to produce the F₁ generation, which were advanced to F₂ and F₃. Each hybrid generation and their respective parents were evaluated for their adaptive value at two sites in a randomised complete block design with seven replicates. The resulting progenies did not show serious fitness penalties. Some hybrids were as fit as their respective wild parents and no consistent differences exist between the three generations studied. Thus, the resultant wild × cultivated hybrids may act as avenue for introgression.     

Recombination around the <Emphasis Type="Italic">P</Emphasis> locus for long glume phenotype in experimental introgression lines of <Emphasis Type="Italic">Triticum aestivum</Emphasis> – <Emphasis Type="Italic">Triticum polonicum</Emphasis>

A set of experimental introgression lines of Triticum aestivum L. cv. Novosibirskaya 67 (N67)—Triticum polonicum L. line IC 12196 was developed using a small-scale bulk breeding method. The linkage map in chromosome 7A was constructed using F₂ hybrids of N67/IC12196 and 34 microsatellite markers. The P gene was flanked by the centromeric markers, Xgwm890 (18.6 cM) and Xbarc108 (20.0 cM) on the long arm of chromosome 7A. Among 124 introgression lines, 118 lines were hexaploid (2n = 6x = 42), and 6 were tetraploid (2n = 4x = 28). Among hexaploid accessions, 68 were long-glumed, whereas 50 were normal-glumed. Thirty-four polymorphic microsatellite markers were scored for either the N67 alleles or IC 12196 alleles in 124 introgression lines derived from N67/IC 12196. The UPGMA dendrogram showed five clusters; Cluster 1 mainly contained hexaploid introgression lines with long glumes. Although the alleles around the P locus were recombined with IC1296 alleles, the distal end of the chromosome contained N67 alleles. Cluster 2 mainly contained normal glumed, hexaploid introgression lines. These predominantly had the N67 alleles on the long arm of chromosome 7A and the short arm proximal to the centromere. Cluster 3 contained long-glumed, hexaploid wheat lines with relatively high level of recombination. Cluster 4 contained non-parental alleles. Cluster 5 contained the group of tetraploid wheat lines. These tetraploid lines have IC12196 alleles on both arms of chromosome 7A. The frequency spectrum of parental alleles and chromosomal blocks among introgression lines suggested that T. aestivum – T. polonicum hybridization can rapidly give rise to a new landrace due to selective introgression of the P gene.     

Taxonomic remarks on <Emphasis Type="Italic">Triticum</Emphasis> L. and ×<Emphasis Type="Italic">Triticosecale</Emphasis> Wittm.

The recent treatment of Triticum by Mac Key (2005) (broad species concept) is compared to the classical treatment by Dorofeev et al. (1979, English translation expected) (narrow species concept). A detailed infraspecific treatment was abandoned by Mac Key. Following his revision, names for many of the infraspecific taxa become obsolete. This is regarded to be a disadvantage for biodiversity and genetic resources studies. We propose maintaining ×Triticosecale Wittm. as a nothogenus, with ×T. rimpaui Wittm. for octoploid races, ×T. neoblaringhemii A. Camus for hexaploid races and ×T. semisecale (Mac Key) K. Hammer et A. Filat. (new combination) for tetraploid races.     

动态GPS<RTK>在土地平整测量中的应用

RTK在测量中具有独立性,便携性,可自由移动;除此之外其铝合金外壳,结构密封,防雨淋。而且可多模式供电,可自动切换,并且有电源防反接保护、过流过热保护功能。现结合土地平整状况测量,介绍RTK的工作原理和方式,并对RTK应用中数据传输、坐标转换等问题进行讨论。     

授粉方法对克服百合‘cordelia’×毛百合远缘杂交障碍的影响

研究了辐照花粉辅助授粉、杂交液辅助授粉及切割花柱授粉等措施对克服百合‘cordelia’(♀)×毛百合远缘杂交障碍的影响。结果表明:采用普通柱头授粉能够获得许多膨大果实和饱满种子,表明该杂交组合为亲合性组合。用经1000Gy或2500Gy剂量60Co辐照的母本花粉进行辅助授粉明显地提高了座果率和饱满种子结籽数,表明两种剂量的辐照花粉辅助授粉均能有效地克服该组合的杂交障碍。结籽数的提高有利于后续的选育工作。采用杂交液辅助授粉,座果率和饱满种子结籽数有所提高。而切割花柱授粉明显地减少了座果率和结籽数,表明该方法不适合于克服‘cordelia’(♀)×毛百合杂交障碍。     

Inflorescence-visiting insects of a functionally dioecious wild grapevine (<Emphasis Type="Italic">Vitis vinifera</Emphasis> subsp. <Emphasis Type="Italic">sylvestris</Emphasis>)

The wild grapevine [Vitis vinifera L. subsp. sylvestris (Gmelin) Hegi] is the Eurasian dioecious ancestral form of mostly monoecious domesticated cultivars (Vitis vinifera subsp. vinifera). There are different hypotheses about grapevine pollination, varying from insect to wind pollination to spontaneous self-pollination. The aim of this paper is to update our knowledge on the biology of the wild grapevine by studying the insects visiting their inflorescences. During the fieldworks, floral visitors were observed, captured and identified. The most frequent insects visiting both sexes of wild grapevine were beetles (55%) followed by bees (45%). The present study shows that although in vineyards the wind may play a role in the cross-pollination, insects can contribute to the reproductive success of the wild grapevine. The knowledge of inflorescence-visiting insects, which potentially can act as pollinators may represent an important contribution to the conservation perspective of wild grapevine.     

甘肃舟曲“8·7”特大山洪泥石流灾害原因及防治对策

 2010年8月7日,甘肃省舟曲县暴发了特大山洪泥石流灾害,给舟曲人民带来了重大的生命和财产损失。通过对甘肃舟曲"8.7"特大山洪泥石流灾害形成原因进行系统的分析,认为特殊的地质地貌条件是灾害发生的潜在原因,突发性强降雨是诱发灾害的动力因素,不合理的人类活动则加剧了灾情的损失和严重程度。在此基础上,提出深入地质灾害基础研究,强化水利水土保持工程建设,退耕还林,注重生态环境保护,规范施工,加快城市基础设施建设,健全灾害监测预警网等防治舟曲及类似地区泥石流灾害的防治对策。     

土壤·植物营养·环境 词汇

1.词汇内容有以下6大部分:土壤、植物营养与肥料、生态、资源、环境污染与防治和农业技术。2.本词汇特色:词汇的编排按汉英分类、英汉对照和汉文索引3种方式。汉英分类部分是按学科性质、内容     

Application of Novel Fulvic Acid-Coated Magnetite Nanoparticles for CO<Subscript>2</Subscript><Superscript>−</Superscript>-Mediated Photoreduction of Cr(VI)

We here isolate fulvic acids from vermicompost to prepare and characterize novel fulvic acid-coated magnetite nanoparticles. UV-A irradiation of suspensions of the nanoparticles under different experimental conditions led to photo-reduction of Cr(VI). In anoxic conditions in the presence of formic acid, after 60 min of irradiation ca. 100% of Cr(VI) was reduced. Under these conditions, the carbon dioxide radical anions, CO₂ ^.- , mediated the photo-reduction of Cr(VI). However, the high reduction potential of Cr(VI) and the variety of reactive species generated upon UV-A irradiation make this nanomaterial also suitable for Cr(VI) photo-reduction also under aerobic conditions in the presence of formic acid or under anoxic conditions without the addition of formic acid. The possible photodegradation routes involved are discussed in detail.