Dynamic changes of nucleolar DNA configuration and distribution during the cell cycle in Allium sativum cells

To investigate the correlation between subnucleolar structure and function, the precise distribution and configuration of nucleolar DNA during the cell cycle of Allium sativum were determined using the NAMA-Ur DNA-specific staining technique. We showed that nucleolar DNA is present in two forms: compacted chromatin clumps and a decondensed DNA cloud. The form of the DNA within the nucleolus varied greatly as the cell cycle progressed. During telophase, chromosomes extended into the prenucleolar body. In early G1 phase, DNA was only located in the fibrillar centers in the form of the condensed chromatin clump, while in mid-G1, S and G2 phases, the two forms of DNA were distributed in the fibrillar centers (FC) and dense fibrillar component (DFC). In prophase of mitosis, nucleolar DNA, along with FC and DFC, was linked into a network structure and condensed into a large chromatin clump. The area of the DNA cloud in the dense fibrillar component changed during different phases of the cell cycle. Our results demonstrated that the configuration of nucleolar DNA undergoes a series of decondensations and condensations during the cell cycle to fulfill the function of the nucleoli during the different phases.     

Cytogenetic changes induced by aqueous ferrofluids in agricultural plants

In this paper, the authors present their results regarding the cellular division rate and the percentage of chromosomal aberrations in the root meristematic cells of agricultural plants when cultivated in the presence of different concentrations of aqueous ferrofluid, ranging between 10 and 250 μL/L. The agricultural species (Zea mays) with a major role in the life of people was chosen for the experimental project. The water-based ferrofluid was prepared following the chemical co-precipitation method, using tetramethylammonium hydroxide as magnetite core stabilizer. Microscopic investigations (cytogenetic tests) resulted in the evaluation of the mitotic and chromosomal aberration index. They appeared to increase following ferrofluid addition.     

Deposition of 15N into Soil Layers of Different Proximity to Roots by Wheat Plants

Abstract

The translocation of root borne N compounds to different distances from the roots was studied by use of rectangular pots with three separated soil zones. Wheat plants were grown for 28 days (4 leaf stage) and subsequently pulse labelled by exposure to 15 ppm ¹⁵NH₃ (generated from (¹⁵NH₄)₂SO₄ with 95 at.-% ¹⁵N exc.) every other day with the rooting medium sealed from the atmosphere. Six pulses were applied in total.

The plants assimilated 65% of the label offered. The final ¹⁵N enrichment in the shoots was approx. 13 at.-% exc. and in the roots approx. 5 at.-% exc. These abundances were high enough to detect traces of ¹⁵N in soil approximately 1 cm distant from the roots. Most of the ¹⁵N recovered was retained in the shoots (about 90%), 5% were present in the roots and another 5% had been released into the rhizosphere. Considering the ¹⁵N released, 62% were found in the central root zone, 26% in the adjacent layer and 12% in the outer zone.     

FTIR结合热重(差热)技术对红壤地区大豆铝毒害的鉴定

采用傅里叶变换红外光谱法(FTIR), 结合热重和差热分析对不同铝浓度下的大豆根系进行了研究。结果表明, 在60和90 mg·L-1的铝液处理下,大豆根系的铝含量较高,达到显著铝毒害水平。在相同的波数范围内,不同铝浓度下其红外谱图的性状、波数及吸收峰的数目有所不同,3 300, 2 930, 1 542和721 cm-1下的吸收峰可作为鉴定大豆铝毒害的特征峰。3 300和2 930 cm-1特征峰在高浓度(60和90 mg·L-1)的铝毒害下明显高于其他浓度特征峰,1 542 cm-1的酰胺Ⅱ带特征峰在90 mg·L-1下没有显现, 721 cm-1吸收峰带却在Al 60和90 mg·L-1浓度下有表现。不同铝浓度下的热重(TG)和差热(DT)曲线在400～500 ℃温度范围内差别最大,TG曲线在大于30 mg·L-1的铝处理下与空白相比的质量损失减少,表明铝处理可能使根系木质化加重,产生难以燃烧的物质;DT曲线在60和90 mg·L-1的铝处理下出现双峰,可作为大豆铝毒害的鉴定标志之一。由此,FTIR结合热重(差热)技术可以用来鉴定红壤地区大豆的铝毒害。     

核仁的细胞辐射应激功能研究进展

核仁是细胞核内核糖体合成、 加工的场所。 最近研究发现核仁参与多种细胞过程, 其中最为重要的就是细胞应激反应。 核仁作为细胞应激感受器, 调控ARF等多种蛋白的定位及P53等关键蛋白的活性等, 从而介导细胞的应激反应。 对核仁的细胞辐射应激功能研究进展进行了综述。 Nucleoli is the sites for ribosome synthesis and processing, however, recent approaches have revealed that it is also involved in variety of cellular processes, especially the cellular stress response. As sensors, nucleoli regulate the localization of nucleolar proteins, such as (Alternate Reading Frame, ARF), and the activation of key factors, such as P53, and consequently mediate the cellular stress response. In this paper, recent progress in the studies on nucleolar functions in cellular stress response to radiation is reviewed.     

外源柠檬酸缓解大豆根系短期铝胁迫的FTIR特征分析

选择耐铝性不同的2个大豆品种浙春2号(耐铝性)和浙春3号(铝敏感)作为实验材料,在设置铝胁迫的同时添加外源柠檬酸处理,应用傅里叶变换红外光谱法(FTIR)对外源柠檬酸协同铝胁迫下的大豆根组织干燥粉末进行直接测定,并对其特征吸收峰进行了归属。通过对各图谱的比较分析,铝处理下大豆根的红外吸收峰形及峰强有所区别,特别是1 057, 1 602, 2 927和3 297 cm-1左右的吸收峰区别明显,反应出蛋白质,糖类以及核酸等有机物的含量变化;以A_{2 927 cm-1}/A_{3 297 cm-1}为横坐标、A_{1 051 cm-1}/A_{1 602 cm-1}为纵坐标而绘制的二维分析图显示,外源柠檬酸的加入使不同处理的红外吸收峰形及峰强差异降低,意味着有机物等有效成分的变化不显著,且浙春3号尤为明显。实验表明FTIR在某种程度上能够反映外源柠檬酸对铝胁迫下大豆根的缓解效应,为该领域的研究工作提供了有益的参考。     

Der [15N]Methacetin-Leberfunktionstest zum Nachweis von Arzneimittelnebenwirkungen. Antibiotika-Therapie mit Amplicillin und mit Gefotaxime bei Neugeborenen

Abstract

The effect of soil temperature and moisture on plant growth and mineralisation of organic residues was investigated using ¹⁵N-labelled soybean residues and temperature-controlled tanks in the glasshouse. Treatments were arranged in a factorial design with: three soil temperatures (20, 26 and 30°C), two soil moisture regimes (8% (–800 Kpa) or 12% (–100 Kpa)), soybean residues added (enriched at 1.82 atom % ¹⁵N excess) or no residues; and either sown with ryegrass or not sown. Pots were sampled six weeks after planting and ¹⁵N-enrichment and δ¹³C of the plant and soil fractions were determined. Soil inorganic N was also periodically measured.

Available inorganic N increased significantly with addition of residues and generally decreased with increasing temperature. Plant dry matter decreased significantly with increase in soil temperature and increased with increasing moisture. Root-to-shoot ratio declined with increased temperature and moisture. Percentage nitrogen derived from residues (%Ndfr) increased linearly with increased temperature and moisture. Δ¹³C decreased linearly with increasing temperature and decreasing moisture status. There was a significant correlation between transpiration and dry matter production, but there was no correlation between water use efficiency and Δ¹³C.

The results suggest that C: N ratio of the root material effects the root turnover and in turn the water supply capacity of the root system.     

New insights on the role of ROS in the mechanisms of sonoporation-mediated gene delivery

Reactive oxygen species (ROS) are hypothesized to play a role in the sonoporation mechanisms. Nevertheless, the acoustical phenomenon behind the ROS production as well as the exact mechanisms of ROS action involved in the increased cell membrane permeability are still not fully understood. Therefore, we investigated the key processes occurring at the molecular level in and around microbubbles subjected to ultrasound using computational chemistry methods. To confirm the molecular simulation predictions, we measured the ROS production by exposing SonoVue® microbubbles (MBs) to ultrasound using biological assays. To investigate the role of ROS in cell membrane permeabilization, cells were subjected to ultrasound in presence of MBs and plasmid encoding reporter gene, and the transfection level was assessed using flow cytometry. The molecular simulations showed that under sonoporation conditions, ROS can form inside the MBs. These radicals could easily diffuse through the MB shell toward the surrounding aqueous phase and participate in the permeabilization of nearby cell membranes. Experimental data confirmed that MBs favor spontaneous formation of a host of free radicals where HO was the main ROS species after US exposure. The presence of ROS scavengers/inhibitors during the sonoporation process decreased both the production of ROS and the subsequent transfection level without significant loss of cell viability. In conclusion, the exposure of MBs to ultrasound might be the origin of chemical effects, which play a role in the cell membrane permeabilization and in the in vitro gene delivery when generated in its proximity.     

Radiocarbon in plant products: Geography,Species, and time

Carbon¹⁴ measurements, on a global scale, have been made on a large number of essential oils obtained from various plants. The measurements allow conclusions to be drawn on the mixing of some compartments of the atmosphere and, in addition, metabolic differences between various species of plants are demonstrated. The course of C¹⁴ fallout, as recorded by the various plants, is charted.     

Confocal Raman microspectroscopy discriminates live human metastatic melanoma and skin fibroblast cells

Confocal Raman microspectroscopy (CRM) continues to develop as a promising technique with possible clinical applications for the diagnosis and treatment of skin cancers. CRM studies of single cells can provide information on the biochemical content of cancer cells in situ, potentially providing new biochemical signatures or markers of cancer cells. Here, we report a CRM study of single, living human metastatic melanoma cells (SK‐Mel‐2) and normal skin fibroblast cells (BJ) cultured and examined under identical experimental conditions. A total of almost 1200 Raman spectra were measured from more than 120 BJ and SK‐Mel‐2 cells using an inverted microscope with 647 nm laser excitation. Raman spectra were measured from within three distinct intracellular regions of the cells – cytoplasm, nucleoplasm, and nucleolus. When Raman spectra from each cell type were compared using principal components analysis (PCA) and linear discriminant analysis with leave‐one‐dish‐out cross‐validation (LDA‐CV), the two cell types were discriminated with 93% (cytoplasm), 98% (nucleolus), and 96% (nucleoplasm) accuracy. The main biochemical differences identified between the two cell types were higher RNA levels in the nucleoli of BJ cells and high amounts of lipid and collagen in the cytoplasm of SK‐Mel‐2 cells. For both cell types, higher levels of RNA were detected in the nucleoli versus the nucleoplasm. PCA with LDA‐CV was 98% (cytoplasm), 93% (nucleoplasm), and 73% (nucleolus) accurate in identifying the intracellular region based on the Raman spectra from both cell types. No significant trend was observed when the data were analyzed with respect to cell passage number. Thus, CRM with PCA and LDA‐CV successfully discriminated two skin cancer‐relevant cell lines while detecting different amounts of nucleic acids, lipids, and proteins in distinct intracellular regions, further underscoring its potential as a clinical diagnostic tool. Copyright © 2013 John Wiley & Sons, Ltd.     

Sprinkler irrigation uniformity: Impact on the crop yield and water use efficiency

In this work, an assessment of the effect of distribution uniformity over water use efficiency is shown. The experimental study took place in Sebha region, southern Libya, characterized by arid climate and interested a barley field. The results of water irrigation in the sprinkler irrigation system with respect to the operating pressure (P) and raiser height of sprinkler (H) are reported with respect to distribution uniformity and water use efficiency. The main objective of irrigation is to apply the optimum amount of water to the crop root zone that is needed for its growth and maturation, and it is, hence, important for to check the uniformity of irrigation systems in order to adjust the operating parameters involved. To assess uniformity, the coefficient of uniformity (CU), the low quarter distribution uniformity (DU), and the coefficient of variation (CV) were considered, while the grain yield (GY), the crop height (CH) and the water use efficiency (WUE) weremeasured in order to find the best solution in terms of operating conditions. The highest values reached by the uniformity parameters with varying the operating conditions defined the best operating practices under which the irrigation system works efficiently: the results demonstrated that the maximum values for CU and DU, 91.37% and 0.85, respectively, were obtained at the highest P and H, and under the same conditions, also grain yield, plants height and WUE recorded the highest values: 5.50 t·ha^?1, 63.49 cm and 0.75 kg·m^?3, respectively. The results emerged in this work can be useful for similar arid regions like Sebha region, in order to solve the problems related to water scarcity and water use efficiency.     

Solidification of selenium melt under pressure up to 6.5 GPa

Abstract

High purity selenium samples were melted under high pressure (≤6.4 GPa) and quenched at various rates ranging from 2 K s^?1 to 500 K s^?1 and the recovered material was examined by X-ray diffraction and electron microscopy. In the entire range of pressure and cooling rate, the melt was found to solidify into a polycrystalline aggregate of the trigonal phase of selenium. The samples obtained by slow cooling of the melt at 6.4 GPa contain, in addition to crystalline phase, regions which appear to be amorphous.     

Densification of Crystalline Boron Carbide during Shock-Wave Loading

Crystalline powder boron carbide samples are subjected to explosive loading by 2-μs shock waves with an amplitude of 38 GPa and shock heating to 700 K and to subsequent conservation. The samples recovered after shock-wave loading are studied by X-ray diffraction, and new effects of shock-wave loading on boron carbide are revealed. The explosive treatment is shown to shift the X-ray diffraction reflections of initial boron carbide toward high angles, which is attributed to an increase in the boron carbide density at the level of atomic volume in the unit cell of boron carbide. The X-ray diffraction reflections are found to broaden, which is interpreted as an increase in the coherent scattering region in the crystalline boron carbide subjected to the explosive treatment.     

超微弱发光用于番茄果实冷害发生程度的无损监测

超微弱发光测定法可快速、灵敏地反映生物体在逆境下的生理状态,已开始得到广泛应用,但有关其在采后园艺产品冷害发生监测中的应用尚未见报道.文章通过分析番茄果实在不同冷害状态下的超微弱发光规律,及其与冷害程度问的关系,探讨超微弱发光测定法在监测采后番茄果实冷害中应用的可能性.结果表明,果实超微弱发光强度随冷害程度的提高而上升,且在表现冷害症状前,冷害果实的超微弱发光值已显著高于正常果实(P<0.01).不同冷害程度下果实的冷害发病率、冷害指数分别与超微弱发光值的相关系数达到0.901 6和0.957 7(P<0.01),证明超微弱发光可以准确反映番茄果实冷害程度.     

X‐ray absorption spectroscopy at the Ni?K edge in Stackhousia tryonii Bailey hyperaccumulator

Young plants of Stackhousia tryonii Bailey were exposed to 34 mM Ni kg^?1 in the form of NiSO₄· 6H₂O solution and grown under controlled glasshouse conditions for a period of 20 days. Fresh leaf, stem and root samples were analysed in vivo by micro x‐ray absorption spectroscopy (XAS) at the Ni? K edge. Both x‐ray absorption near edge structure and extended x‐ray absorption fine structure spectra were analysed, and the resulting spectra were compared with spectra obtained from nine biologically important Ni‐containing model compounds. The results revealed that the majority of leaf, stem and root Ni in the hyperaccumulator was chelated by citrate. Our results also suggest that in leaves Ni is complexed by phosphate and histidine, and in stems and roots, phytate and histidine. The XAS results provide an important physiological insight into transport, detoxification and storage of Ni in S. tryonii plants. Copyright © 2008 John Wiley & Sons, Ltd.     

基于分数阶微分算法的大豆冠层氮素含量估测研究

氮素与作物的生长发育、产量和品质密切相关。作物冠层氮素含量的快速、准确、无损检测对于作物营养诊断和长势评估具有重要意义。传统的氮素检测方法检测周期长、操作复杂,同时具有破坏性,无法实现作物氮素含量在时间和空间上的连续动态监测。基于光谱遥感技术快速、无损地获取作物氮素含量是近年来作物组分快速检测研究的热点。当前的研究大多基于原始光谱或整数阶微分(一阶、二阶)预处理后的光谱进行氮素含量预测,原始光谱或整数阶微分预处理后的光谱会忽略光谱曲线间的渐变信息,影响氮素含量的预测准确度。与原始光谱和整数阶微分方法相比,分数阶微分算法在背景噪声去除、有效信息提取等方面较有优势。为研究分数阶微分预处理算法在作物氮素检测中的应用,本文以不同施肥处理下的盆栽大豆作物为研究对象,获取大豆苗期、花期、结荚期和鼓粒期四个生育期共256组冠层高光谱及对应的大豆冠层氮素含量(CNC)数据,运用分数阶微分算法对光谱数据进行0～2阶微分预处理,微分间隔为0.1,分别采用归一化光谱植被指数NDSI、比值光谱指数RSI对预处理后的光谱数据和大豆冠层氮素含量数据进行相关性分析,得到各阶微分预处理下NDSIα(α代表分数阶微分阶数)与大豆CNC,RSIα与大豆CNC相关系数绝对值的最大值及其对应的波段组合--最优波段组合NDSIα(opt)和RSIα(opt),采用线性回归方法,建立各阶微分下NDSIα(opt)与CNC,RSIα(opt)与CNC的预测模型,并与常用植被指数(VOGII, MTCI, DCNI, NDRE)建立的氮素含量预测模型进行比较,研究分数阶微分算法对大豆作物冠层氮素含量预测模型的效果。结果表明：(1)在0～2阶微分范围内,最优波段组合NDSIα(opt),RSIα(opt)与大豆CNC的相关系数随阶数增加呈现先升高后下降趋势。其中,0.8阶微分下NDSI_0.8(R₇₂₅, R₇₆₉)与大豆CNC的相关系数最大,为0.875 9;0.7阶微分下RSI_0.7(R₅₄₈, R₇₆₇)与大豆CNC的相关系数最大,为0.865 1;(2)分数阶微分预处理能够细化光谱数据中的有效信息,增强光谱数据对冠层氮素含量的敏感性,尤其是增强红边平台波段与氮素含量的正相关性及绿波段与氮含量的负相关性;(3)与整数阶微分、常用植被指数相比,分数阶微分能够提高大豆CNC预测模型的准确性。其中,基于0.7阶微分RSI_0.7(R₅₄₈, R₇₆₇)建立的大豆CNC预测模型与0阶微分RSI₀(R₇₂₅, R₇₆₉)相比建模集决定系数(R2_C)和预测集决定系数(R2_P)分别提高了0.061 9和0.016 6,建模集均方根误差(RMSEC)和预测集均方根误差(RMSEP)分别降低了0.552 5和0.180 9,预测相对偏差(RPD)提高了0.110 4。基于0.7阶微分RSI_0.7(R₅₄₈, R₇₆₇)建立的大豆CNC预测模型与VOG II相比R2_C和R2_P分别提高了0.086 6和0.025 5,RMSEC和RMSEP分别降低了0.757 5和0.248 3,RPD提高了0.146 88;(4)基于0.7阶微分比值光谱指数RSI(R₅₄₈, R₇₆₇)建立的大豆LNC预测模型较优,其R2_C为0.748 4,R2_P为0.800 3,RMSEC为4.752 9,RMSEP为3.511 1,RPD为2.253 7,能够较好的估测大豆冠层氮素含量。研究表明分数阶微分算法在大豆冠层氮素含量的定量预测中具有一定的优势,为光谱遥感技术在作物氮营养检测中的应用开拓了新的思路。     

Determination of replacement of some inorganic elements in pulvinus of bean (Phaseolus vulgaris cv. Gina 2004) at chilling temperature by the WDXRF spectroscopic technique

In this study, bean seedlings (Phaseolus vulgaris cv. Gina 2004) were exposed to chilling temperatures until leaves are wrinkled (9 day), that is, showed nyctinastic movement. Pulvinus were subsequently were cut from the leaves. Concentrations of inorganic elements (P, S, Cl, K, Ca, Cu) in the pulvinus were measured by wavelength-dispersive X-ray fluorescence (WDXRF) spectrometry. Results indicated that concentration change (%) was not significant for Ca (0.82) but it was significant for K, P, Cl, S, and especially Cu concentrations (5.4%, 12.8%, 40.2%, 43.7%, 365%, respectively) in pulvinus of plants exposed to chilling temperature compared with control group.We hypothesize here the presence of association between nyctinasti movement brought about by pulvinus at chilling temperature in bean and changes of K, P, Cl, S and especially Cu concentrations measured by WDXRF analysis method.     

Chill tolerance in the tropical beetle Stenotarsus rotundus

The tropical beetle Stenotarsus rotundus (Endomychidae) survived chilling at mildly low temperatures (above +5 degree C). With upper limit of cold injury zone (ULCIZ, the highest temperature that causes cold injury) well above freezing point, the supercooling ability (mean supercooling point - SCP; -11 degree C) has no cryoprotective importance. Mortality increases rapidly between -9 and +5 degree C, dependent on accumulated dose of chilling (sum of injurious temperatures - SIT; 2 degree-days below ULCIZ). The cold hardiness traits found in this species are by-products of deep diapause, and may serve as pre-adaptation for expansion into cooler regions.