Morphological Investigation of Calcium Carbonate during Ammonification-Carbonization Process of Low Concentration Calcium Solution

Ultrafine calcium carbonate is a widely used cheap additive. The research is conducted in low degree supersaturation solution in order to study the polymorphic phases’ change and its factors of the calcium carbonate precipitate in the ammonification-carbonization process of the solution with calcium. Fine particles of calcium carbonate are made in the solution containing 0.015 mol/L of Ca2+. Over 98% of the calcium carbonate precipitate without ammonification resembles the morphology of calcite, while the introduction of ammonia can benefit the formation of vaterite. It was inferred that the main cause should be serious partial oversaturation or steric effects. Ammonia also helps to form the twin spherical calcium carbonate. However, particles formed in the process of ammonification-carbonization in solution with low concentration degree of calcium are not even with a scale of the particle diameter from 5 to 12 μm. Inorganic salts, alcohol, or organic acid salts have significant controlling effect on the particle diameter of calcium carbonate and can help to decrease the particle diameter to about 3 μm. Anionic surfactants can prevent the conglobation of calcium carbonate particles and shrink its diameter to 500 nm–1 μm

De novo Transcriptome Assembly and Comparative Analysis Highlight the Primary Mechanism Regulating the Response to Selenium Stimuli in Oats (Avena sativa L.)

Selenium is an essential microelement for humans and animals. The specific processing technique of oats can maximize the preservation of its nutrients. In this study, to understand the genetic response of oats in a high-selenium environment, oats were treated with sodium selenate for 24 h, and transcriptome analysis was performed. A total of 211,485,930 clean reads composing 31.30 Gb of clean data were retained for four samples. After assembly, 186,035 unigenes with an average length of 727 bp were generated, and the N50 length was 1,149 bp. Compared with that in the control group, the expression of 7,226 unigenes in the treatment group was upregulated, and 2,618 unigenes were downregulated. Based on the sulfur assimilation pathway and selenocompound metabolic pathway, a total of 27 unigenes related to selenate metabolism were identified. Among them, the expression of both key genes APS (ATP sulfurylase) and APR (adenosine 5′-phosphosulfate reductase) was upregulated more than 1,000-fold under selenate treatment, while that of CBL (cystathionine-β-synthase) was upregulated 3.12-fold. Based on the transcriptome analysis, we suspect that the high-affinity sulfur transporter Sultr1;2 plays a key role in selenate uptake in oats. A preliminary regulatory mechanism explains the oat response to selenate treatment was ultimately proposed based on the transcriptome analysis and previous research

Involvement of nitric oxide synthase-dependent nitric oxide and exogenous nitric oxide in alleviating NaCl induced osmotic and oxidative stress in Arabidopsis thaliana

To elucidate the roles of endogenous nitric oxide on Arabidopsis thaliana tolerance to salt stress, a moderate concentration of NaCl was applied to wild-type (WT) and mutant (Atnoa1) plants which have an impaired in vivo nitric oxide synthase and reduced endogenous nitric oxide content due to T-DNA insertion in the first exon of the NOA1 gene. The exhibited greater inhibition of root growth, higher leaf water loss (LWL), lower contents of chlorophyll, soluble protein, proline, higher activities of peroxidase (POD), ascorbate peroxide (APX), and gluthinone reductase (GR), it also showed lower activities of superoxide dismutase (SOD) and catalase (CAT) than wild-type plants under NaCl stress. The nitric oxide synthase (NOS) inhibitor NG-nitro-L-Arg (L-NNA) enhanced NaCl induced growth inhibition, osmotic stress, and oxidative stress in wild-type plants. Meanwhile the NO donor, sodium nitroprusside (SNP), alleviated the NaCl induced damages in Atnoa1 plants. These results indicate that both NOSdependent endogenous NO and exogenous NO were involved in salt resistance in A. thaliana. Key words: Antioxidant enzymes, Arabidopsis thaliana, reactive oxygen species. INTRODUCTION Earth is a salty planet, with most of its water containing about 30 g of sodium chloride per litre. this salt solution has affected, and continues to affect, the land on which crops are, or might be, grown. Although the amount of salt-affected land (about 900×106 ha) is imprecisely known, its extent is sufficient to pose a threat to agriculture Recently, nitric oxide (NO) has been suggested to be an important signaling molecule in plants (Neill et al., 1714 Afr. J. Agric. Res. 2003; Nitric oxide synthase (NOS)-like activity has been widely detected in plants, and NO generation has been inhibited by mammalian NOS inhibitors in plants ( MATERIALS AND METHODS Plant material and growth conditions Wild-type Arabidopsis (Arabidopsis thaliana) L. Heynh. ecotype Columbia and Atnoa1 plants were grown on pot vermiculite (vermiculite : soil =3:1) in a greenhouse under conditions of 14 h photoperiod with irrandiance of 120 µmol m-2 s-1, temperature of 25±2°C and air humidity 60-70%. Treatments Four-week-old wild-type plants were divided into three groups: group 1 was irrigated with 150 mmol L -1 NaCl, group 2 was irrigated with 150 mmol L -1 NaCl + 300 µmol L -1 L-NNA and group 3 was irrigated with water and was used as control. Four-week-old Atnoa1 plants were also divided into three groups: group 1 was irrigated with 150 mmol L -1 NaCl, group 2 was irrigated with 150 mmol L -1 NaCl +150 µmol L -1 SNP and group 3 was irrigated with water and was used as control. All the treatments were fulfilled with at least three replicates. Plant physiological parameters determination Leaf water loss (LWL) was determined according to the method of Leaves of wild-type and Atnoa1 plants were sampled at the same leaf order from the leaf base after 48 h treatment. Pigments were extracted from leaf samples (300 mg) with 5 ml of 80% acetone until complete bleaching. The extracts were subjected to spectrophotometric measurements at 645 and 663 nm After 24 h treatment, plant leaf protein content was determined according to For enzyme extraction, 24 h treated fresh leaves (0.5 g) were homogenized in 5 ml ice-cold 50 mM sodium phosphate buffer (pH 7.8) containing 1% polyvinyl-polypyrrolidone. The homogenate was centrifuged at 10000 g for 20 min, and the supernatant was used for assaying the enzyme activities. SOD activity was determined by monitoring its ability to inhibit photochemical reduction of nitroblue tetrazolium (NBT) at 560 nm POD activity was determined using the guaiacol oxidation method CAT (EC 1.11.1.6) activity was determined by monitoring the disappearance of H2O2 and by measuring the decrease in absorbance at 240 nm of a reaction solution containing 0.3 ml of 3% H2O2, 2.5 ml of 50 mM phosphate buffer (pH 7.0), and 0.2 ml of the extract APX (EC 1.11.1.11) activity was measured in 1 ml reaction volume containing 50 Mm potassium phosphate buffer (pH 7.0), 0.1 Mm hydrogen peroxide and 0.5 mM ascorbate. The H2O2 was Zhang et al. (1) Control; (2) NaCl; (3) NaCl+L-NNA; (4) Control; (5) NaCl; (6) NaCl +SNP added to start the reaction, and the decrease in absorbance at 290 nm was recorded for 1 min to determine the oxidation rate for ascorbate Plant root growth determination Root growth was determined by measuring root length. Wild-type plants grown on Murashige and Skoog (MS) solid medium Statistics analysis was conducted by SPSS for windows (version 15.0). Least significant difference (LSD) test was employed to determine differences among the treatments at p<0.05. All the values were mean ± SE. RESULTS As shown in The salt stress treatment reduced chlorophyll and soluble protein content in both wild-type and mutant plants. However, the decreases were more pronounced in the mutants. Inhibition of NO accumulation decreased chlorophyll and soluble protein content in salt stressed wild-type plants (P's < 0.05 vs. NaCl stressed wild-type group). Meanwhile, exogenous NO increased chlorophyll and soluble protein content in the salt stressed mutant plants (P's < 0.05 vs. NaCl stressed mutant group) ( Proline content was 87.7% higher in wild-type plants than that in the mutant plants following administration of NaCl (P < 0.05). Specifically, salt stress increased proline content by 2212.9% in wild-type plants and by 170.6% in the mutant plants (P's < 0.05 vs. respective baselines). Application of L-NNA increased proline content in salt stressed wild-type plants by 88.1% (P < 0.05 vs. NaCl stressed wild-type group). However, application of SNP also significantly increased proline content by 639.2% in salt-stressed wild-type plants (P < 0.05 vs. NaCl stressed wild-type group) ( NaCl stress showed different influences on the change of antioxidant enzyme activities in WT and Atnoa1 Arabidopsis seedlings. CAT activity was inhibited by NaCl 1716 Afr. J. Agric. Res

Transfer of stripe rust resistance from Aegilops variabilis to bread wheat

In terms of area, the bread wheat producing regions of China comprise the largest area in the world that is constantly threatened by stripe rust epidemics. Consequently, it is important to exploit new adultplant resistance genes in breeding. This study reports the transfer of stripe rust resistance from Aegilops variabilis to bread wheat resulting in resistant line, TKL2(R). Genetic analysis of the segregating populations derived from a cross between TKL2(R) and a susceptible sister line, TKL2(S), indicated that the adult-plant resistance to Puccinia striiformis f. sp. tritici in TKL2(R) is conferred by a single dominant gene. This gene provided resistance to physiological races currently endemic to China, thus indicating its potential usefulness in wheat breeding.Keywords: Aegilops variabilis, gene transfer, Puccinia striiformis f. sp. tritici, Triticum aestivum, wide hybridizatio

Dynamic Microwave-Assisted Extraction of Arctigenin from Saussurea medusa Maxim

Abstract Dynamic microwave-assisted extraction (DMAE) technique was used for the fast extraction from Saussurea medusa Maxim. In order to achieve the optimal extraction conditions, variables involved in the extraction procedure such as extraction methods, extraction solvents, methanol concentration, ratio of solvent to raw material, extraction time, microwave power and extraction cycles were investigated. Orthogonal L 9 (3) 4 test design in the extraction mode was used for optimization extraction conditions and the maximum content of arctignenin was 10.891 ± 0.003 mg g -1 obtained by once DMAE at 390 W with 50 mL methanol for 20 min. The extraction efficiency of arctigenin with DMAE was higher than other traditional extraction methods

The abundance of homoeologue transcripts is disrupted by hybridization and is partially restored by genome doubling in synthetic hexaploid wheat

Dataset S7. List of nonadditively expressed genes in F1 hybrids derived from AS2255 × AS60. (XLSX 72 kb

Mitotic Illegitimate Recombination Is a Mechanism for Novel Changes in High-Molecular-Weight Glutenin Subunits in Wheat-Rye Hybrids

Wide hybrids can have novel traits or changed expression of a quantitative trait that their parents do not have. These phenomena have long been noticed, yet the mechanisms are poorly understood. High-molecular-weight glutenin subunits (HMW-GS) are seed storage proteins encoded by Glu-1 genes that only express in endosperm in wheat and its related species. Novel HMW-GS compositions have been observed in their hybrids. This research elucidated the molecular mechanisms by investigating the causative factors of novel HMW-GS changes in wheat-rye hybrids. HMW-GS compositions in the endosperm and their coding sequences in the leaves of F1 and F2 hybrids between wheat landrace Shinchunaga and rye landrace Qinling were investigated. Missing and/or additional novel HMW-GSs were observed in the endosperm of 0.5% of the 2078 F1 and 22% of 36 F2 hybrid seeds. The wildtype Glu-1Ax null allele was found to have 42 types of short repeat sequences of 3-60 bp long that appeared 2 to 100 times. It also has an in-frame stop codon in the central repetitive region. Analyzing cloned allele sequences of HMW-GS coding gene Glu-1 revealed that deletions involving the in-frame stop codon had happened, resulting in novel ∼1.8-kb Glu-1Ax alleles in some F1 and F2 plants. The cloned mutant Glu-1Ax alleles were expressed in Escherichia coli, and the HMW-GSs produced matched the novel HMW-GSs found in the hybrids. The differential changes between the endosperm and the plant of the same hybrids and the data of E. coli expression of the cloned deletion alleles both suggested that mitotic illegitimate recombination between two copies of a short repeat sequence had resulted in the deletions and thus the changed HMW-GS compositions. Our experiments have provided the first direct evidence to show that mitotic illegitimate recombination is a mechanism that produces novel phenotypes in wide hybrids

Advances and Prospects in Wheat Eyespot Research: Contributions from Genetics and Molecular Tools

Eyespot disease caused by the soil-borne facultative fungi Oculimacula yallundae and O. acuformis is the major component of the stem-base disease complex of wheat in temperate regions of the world with a cool and wet climate. In this review, we focus on results of genetic studies concerning both partners of the host–pathogen interaction. This comprises analyses of genetic diversity of the pathogen and identification of particular genes within it, evaluation and screening methods for host resistance, resistance sources and genetics of these resistances, breeding of resistant cultivars in wheat, and application of genetic markers in tagging and tracking of eyespot resistance genes. We also attempt to foresee some of the key issues and developments that may occur in future. The identification of markers tightly linked to eyespot resistance genes is the important research focus opening the door to marker-assisted selection of resistant varieties

Allelic Variation and Transcriptional Isoforms of Wheat TaMYC1 Gene Regulating Anthocyanin Synthesis in Pericarp

Recently the TaMYC1 gene encoding bHLH transcription factor has been isolated from the bread wheat (Triticum aestivum L.) genome and shown to co-locate with the Pp3 gene conferring purple pericarp color. As a functional evidence of TaMYC1 and Pp3 being the same, higher transcriptional activity of the TaMYC1 gene in colored pericarp compared to uncolored one has been demonstrated. In the current study, we present additional strong evidences of TaMYC1 to be a synonym of Pp3. Furthermore, we have found differences between dominant and recessive Pp3(TaMyc1) alleles. Light enhancement of TaMYC1 transcription was paralleled with increased AP accumulation only in purple-grain wheat. Coexpression of TaMYC1 and the maize MYB TF gene ZmC1 induced AP accumulation in the coleoptile of white-grain wheat. Suppression of TaMYC1 significantly reduced AP content in purple grains. Two distinct TaMYC1 alleles (TaMYC1p and TaMYC1w) were isolated from purple- and white-grained wheat, respectively. A unique, compound cis-acting regulatory element had six copies in the promoter of TaMYC1p, but was present only once in TaMYC1w. Analysis of recombinant inbred lines showed that TaMYC1p was necessary but not sufficient for AP accumulation in the pericarp tissues. Examination of larger sets of germplasm lines indicated that the evolution of purple pericarp in tetraploid wheat was accompanied by the presence of TaMYC1p. Our findings may promote more systematic basic and applied studies of anthocyanins in common wheat and related Triticeae crops

Characteristics of chemical composition and role of meteorological factors during heavy aerosol pollution episodes in northern Beijing area in autumn and winter of 2015

Heavy aerosol pollution episodes (HPEs) usually start from late autumn and become more serious in winter in Beijing and its vicinity (BIV). In this study, we examine the reasons for the formation and change of HPEs in the areas of northern BIV. The size-resolved chemical components of PM1 and meteorological conditions were investigated during HPEs in autumn and winter of 2015. Stable regional atmosphere and higher atmospheric condensation processes associated with southerly and lower speed wind led to the formation of HPEs. After the start of these HPEs, the concentration of fine particles increased more than twice in several hours. ~80% of the ‘explosive’ growth in PM mass can be considered as a positive feedback of meteorological factors that come from even more stable atmosphere and larger condensation rate of water vapour, which was derived from the interaction between formed aerosol pollution and the meteorological factors within boundary layer. Nitrate was the largest fraction of PM1 in autumn, and the most significantly increased component during HPEs relative to clean period during both of autumn and winter. The proportion of organic aerosol (OA) was similar to that of nitrate in autumn, but its rise in HPE was much smaller, mainly because of the high concentration of OA existed during clean periods. Compared with the largest increase of nitrate, the similar uplift was found for ammonium production, showing that a large amount of ammonium was mainly formed by the combination of ${\text{NO}}_3^-$ in HPEs, rather than ${\text{SO}}_4^{2-}$. In addition to the lower southerly wind carrying pollutants from southern part of BIV, westerly wind from central Inner Mongolia and north Shanxi can also bring air pollutants originating from coal combustion, contributing to the heavy pollution in the northern BIV area in winter, and resulting in higher sulphate, nitrate and OA masses