Wettability of ionic surfactants SDS and DTAB on wheat (Triticum aestivum) leaf surfaces

Abstract

Due to the important use of pesticide formulation, it is necessary to make it clear how ionic surfactant effect the wettability at leaf surface. In this work, we used the sessile drop method to study the wettability of SDS and DTAB on wheat leaf surfaces at different leaf stages, and reveal the relationship between surfactants structures and leaf stages of wheat leaf surfaces on wettability behavior. Results showed that few surfactant molecules adsorbed at the interface at low concentrations. With the concentration increased, the surfactant replaced the air layer partially within the nano/micro structure of leaf surfaces. When the concentration exceeded to CMC, the adsorption of surfactant molecules was saturated at both air-liquid interface and solid-liquid interface, the wetting state was still the transitional state between Cassie-Baxter’s and Wenzel’s state. In all concentrations, the adhesional tension and surface tension showed the linear relationship and the slope values were all below ?1, suggesting there were more surfactant molecules adsorbed at the solid-liquid interface than the liquid-air interface. As SDS is a common wetting agent and DTAB is a common fungicide in agrochemical, this study will provide potential guidance in practical application of pesticide solutions in leaf surface wetting.     

Distribution of cadmium, copper, and zinc in the caryopsis of wheat (Triticum aestivum L.)

Summary Cadmium, copper, and zinc were quantitatively determined in the whole grain, the germ, the aleurone layer, the outer pericarp, and the endosperm from the caryopsis of wheat (Triticum aestivum L.) by the methods of direct solid microsampling and flame-AAS, respectively. Metal concentrations markedly differed among the tissues investigated. Both methods used in this study produced almost identical heavy metal concentrations. However, the techniques dramatically differed in the amounts of grain material required for analysis.

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Verteilung von Cadmium, Kupfer und Zink in der Karyopse des Weizens (Triticum aestivum L.)

Zusammenfassung Es wurde der Cadmium-, Kupfer- und Zinkgehalt in morphologisch definierten Fraktionen des Weizenkornes bestimmt. Als Analysenmethoden dienten die Zeeman-Feststoff-AAS und die Flammen-AAS. Die beiden Analysentechniken lieferten annähernd identische Ergebnisse, unterschieden sich aber deutlich hinsichtlich der für die Analysen notwendigen Probenmengen.

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Lecture given at the colloquium on the Analysis of Solids by AAS, Wetzlar, 8.–10. 10.1984     

Two-dimensional electrophoresis of soluble leaf proteins, isolated from two wheat species (Triticum durum and Triticum aestivum) differing in sensitivity towards NaCl

Plants of two wheat species (Triticum aestivum cv. Tanit and T. durum cv. Ben Bachir), differing in their sensitivity to NaCl were cultivated in the presence or absence of 100 mM NaCl for 21 days. Soluble proteins extracted from leaves were analyzed by two-dimensional electrophoresis in order to detect NaCl-induced changes in the polypeptide patterns. In all, 500 spots were detected. Results showed species-dependent differences. The greatest alterations in the polypeptide profiles following salt stress were found in the most sensitive cultivar: among the 12 spots (molecular mass, 15-31 kDa) specifically considered in the acidic region of the gel, 11 declined, even disappeared in the NaCl-sensitive leaf profiles, while in the tolerant species only five spots were affected by the salt treatment and five remained untouched; moreover in the latter, two new polypeptides were shown to be induced by NaCl.     

RFLP Tagging of a Gene Pm12 for Powdery Mildew Resistance in Wheat (Triticum aestivum L. )

A dominant gene, Pml2, conferring the resistance to powdery mildew (Erysiphe graminis) has been transferred to wheat from Aegilops speltoides. Sixteen RFLP probes were used to test Line 31 and its parents, showing that Line 31 is a 6B/6S translocation lines. The linkage analysis by five probes indicates that Pm12 is located on the chromosome 6B/6S, and tightly flanked by an RFLP marker α-Amy-1 (1.1 cM), identified by RFLP and isozyme analysis. This approach is equally applicable to the identification of other transferred alien genes and the segments of alien chromosome introgressed into wheat.     

Capillary electrophoresis separation of high molecular weight glutenin subunits in bread wheat (Triticum aestivum L.) and related species with phosphate-based buffers

This study focused on optimizing phosphate-based buffers and other capillary electrophoresis (CE) parameters for separating and characterizing high molecular weight glutenin subunits (HMW-GS) in bread wheat (Triticum aestivum L., AABBDD, 2n = 6x = 42), emmer (Triticum dicoccum, AABB, 2n = 4x = 28) and Aegilops tauschii (DD, 2n = 2x = 14). The fast and high-resolution separation of HMW-GS was achieved using 0.1 M phosphate-glycine buffer (pH 2.5, containing 20% acetonitrile and 0.05% hydroxypropylmethylcellulose) at 12.5 kV and 40 degrees C with 25 microm inside diameter (ID)x27 cm uncoated fused-silica capillary. In general, one sample separation can be analyzed in 15 min. The good run-to-run repeatable separation of HMW-GS could be obtained with a relative standard deviation of less than 1% when capillaries were rinsed with 1 M phosphoric acid for 2 min, followed by separation buffer for 2 min after each separation. The HMW-GS from some bread wheat cultivars as well as tetraploid and diploid accessions was separated by the CE method described above, and all subunits detected were well characterized and readily identified. Some HMW-GS showed reversed mobilities and elution order compared to the methods of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and SDS-CE. Particularly, most of the HMW-GS analyzed with the CE buffer used were separated into multiple peaks, generally a high peak plus a minor peak. CE appears to be capable of separating and characterizing HMW-GS with fast and high-resolution features, therefore it is expected to be useful for specific germplasm screening and desirable HMW-GS identification in wheat quality improvement.     

Investigation on dynamic changes of photosynthetic characteristics of 10 wheat (Triticum aestivum L.) genotypes during two vegetative-growth stages at water deficits

Drought is a worldwide problem, seriously influencing plant (crop) productivity. Wheat is a stable food for 35% of the world population, and moreover, about 60% of land area on the globe belongs to arid and semiarid zone. Wheat drought resistance is a multi-gene controlling quantitative character and wheat final production in field is realized mainly by physiological regulation under the condition of multi-environmental factor interaction. Exploring drought resistance physiological mechanisms for different wheat genotypes is of importance to finding new drought resistance gene resources and conventional breeding, and the basis for wheat drought resistance biotechnological breeding and platform. Photosynthesis is the main component for physiological machinery of wheat assimilates conversion and wheat production. Investigation on photosynthetic characteristics of different wheat genotypes at soil water deficits also has other implications for refine physiological regulation of photosynthesis in fields and field management of crops in arid and semiarid areas. By pot-cultivating experiments, investigation of photosynthesis for 10 wheat genotypes at seedling stage and tillering stage at soil water deficits (75%FC, 55%FC and 45%FC, respectively) was conducted. The main results were as followed: developmental stages influenced wheat photosynthesis greatly and tillering stage played more roles; there were significant difference in the main photosynthetic parameters, photosynthesis rate (Photo), stomatal conductance (Cond) and transpiration rate (Tr), among 10 wheat genotypes; general photosynthesis and drought resistance in different wheat genotypes was related much to their domesticated origin soil water environment and selected generations and there was a photosynthetic threshold effect in terms of different wheat genotypes at soil water deficits.     

Crystal structures,electrochemical properties,antioxidant screening and in vitro cytotoxic studies on four novel Cu(II) complexes of bidentate Schiff base ligands derived from 2-methoxyethylamine

Four novel Schiff base ligands and their copper(II) complexes, [Cu(L¹)₂] (1), [Cu(L²)₂] (2), [Cu(L³)₂] (3), and [Cu(L⁴)₂] (4), were synthesized and characterized by elemental analyses, FT-IR, and UV–Vis spectroscopy. The ligands were synthesized from the condensation of 2-methoxyethylamine with various salicylaldehyde derivatives (x-salicylaldehyde for HLⁿ, x = H (n = 1), 5-Br (n = 2), 3-OMe (n = 3), and 4-OMe (n = 4)). The molecular structures of 1, 2, and 3 were determined by the single crystal X-ray diffraction technique. The redox behavior studies of the complexes in acetonitrile display the electronic effects of the groups on the redox potential. The antioxidant activity of the Schiff base ligands and their Cu(II) complexes was evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method and FRAP assay. Furthermore, the in vitro anticancer activity of compounds was screened, including MTT and migration assays against gastric cancer cell line (MKN-45). The results show that all ligands and complexes have antioxidant and anticancer activity in a concentration-dependent way.     

Physico-chemical,Tensile, and Thermal Characterization of Napier Grass (Native African) Fiber Strands

This article presents the extraction and effect of alkali treatment on the physical, chemical, tensile, and thermal characteristics of fiber strands obtained from Napier grass, a renewable biomass. In order to improve these properties, the Napier grass fiber strands were treated with sodium hydroxide. The alkali treatment was carried out using NaOH solution at three different concentrations (5, 10, and 15%) for 2 h. Characterization of untreated and alkali-treated Napier grass fiber strands was carried out by studying the chemical composition, surface morphology, functional group variation, crystallinity, and tensile and thermal behavior. It was found that untreated fiber strands have lower cellulose content, crystallinity, tensile properties, and thermal stability than alkali-treated fiber strands. Napier grass fiber strands treated with 10% NaOH showed optimum tensile strength, modulus, and percentage elongation with an improvement of 51.9, 47.3, and 12.1% respectively. Based on the properties determined for alkali-treated Napier grass fiber strands, we expect that these fibers will be suitable for use as a reinforcement in natural fiber composites.     

Mutagenic, antimutagenic and antioxidant activities of a new polyphenolic and a flavonoid substances isolated from Anagallis monelli

A new polyphenolic natural substance: 2,5-dihydroxy-benzoic acid 3'-formyl-5'-hydroxy-phenyl ester (1), Anamighrinal and 3-(O-alpha-L-rhamnosyl) quercetin (2) have been isolated from the methanolic aerial part extract of the plant Anagallis monelli by chromatographic separation. Their structures have been deduced essentially by one and two NMR spectroscopic procedures and mass spectrometry. Antioxidant, mutagenic, antimutagenic activities, of the natural products were realised and positive results were recorded.     

A Sensitive HPTLC Method for Estimation of Amentoflavone,a Bioactive Principle from Biophytum sensitivum (Linn.) DC. and Putranjiva roxburghii Wall.

JPC – Journal of Planar Chromatography – Modern TLC - A sensitive high-performance thin-layer chromatographic (HPTLC) method has been developed for estimation of amentoflavone, an...     

Structure of cymbidine A, a monomeric peptidoglycan-related compound with hypotensive and diuretic activities, isolated from a higher plant, Cymbidium goeringii (Orchidaceae)

The structure of a new monomeric peptidoglycan-related compound with hypotensive and diuretic activities, cymbidine A (1) isolated from the orchid Cymbidium goeringii, was elucidated mainly by spectroscopic analysis. The structure of 1 was shown to involve four amino acids (D-alanin, meso-diaminopimelic acid, D-gultamic acid, and L-valine) and two amino sugars (N-acetylglucosamine and 1,6-anhydro-N-acetylmuramic acid). The sequence of the amino acids and amino sugars was determined by the analysis of 2D NMR data. The absolute stereochemistries of the three amino acids (D-Ala, D-Glu and L-Val) were determined by the modified Marfey's method, and the (6S,10R) configurations of meso-diaminopimelic acid in 1 were indicated on the basis of the CD analysis. The absolute stereochemistry of 1,6-anhydro-N-acetylmuramic acid was also determined by CD data.     

Screening of several biological activities induced by different sesquiterpene lactones isolated from Centaurea behen L. and Rhaponticum repens (L.) Hidalgo

This study aims to evaluate the in vitro cytotoxic, in vitro and in ovo anti-angiogenic effects and antimicrobial activity of sesquiterpene lactones (SLs) from two plants Centaurea behen and Rhaponticum repens (L.). Five SLs, including cynaropicrin (1), 4β,15-dehydro-3-dehydrosolstitialin A (2), aguerin B (3), janerin (4), cebellin E (5), and a flavone hispidulin (6) were isolated from C. behen (compounds 1–3) and R. repens (compounds 4–6). Cynaropicrin (1) and aguerin B (3) were characterised by strong cytotoxic activities against A2780 cells with IC₅₀ values of 1.15 and 1.62 μg mL^?1, respectively, comparable to that of doxorubicin (IC₅₀ = 1.17 μg mL^?1). The anti-angiogenic study showed the remarkable inhibitory effect of cynaropicrin (1) and aguerin B (3) on the proliferation and migration of HUVECs. In addition, cynaropycrin and aguerin B exhibited significant angio-inhibitory effects in CAM assay. These findings may be useful for the development of novel chemotherapeutic agents for the treatment of cancer.     

Physicochemical characteristics and antitumor activities of a highly branched fungal (1----3)-beta-D-glucan, OL-2, isolated from Omphalia lapidescens.

Physicochemical properties and antitumor activities of a fungal (1----3)-beta-D-glucan, OL-2, isolated from Leiwan (Omphalia lapidescens) were examined. OL-2 showed sharp signals on carbon-13 nuclear magnetic resonance spectrum in dimethylsulfoxide-d6 as a solvent, and these signals were significantly reduced by the addition of distilled water to the concentration of 20%. This phenomenon is consistent with the general property of the gel forming (1----3)-beta-D-glucan. Binding of OL-2 to Congo red induced a significant change of lambda max to a longer wavelength, and the concentration to induce gel to sol transition was about 0.7 N; in contrast, the concentration was about 0.2 N in the cases of SPG and curdlan. These observations suggested that the gel structure would be significantly stabilized in the case of OL-2. OL-2 showed no or low antitumor activity against the solid form of Sarcoma 180 by intraperitoneal and intralesional administrations; however, it was effective on the ascites form of Sarcoma 180. Of interest, OL-2 also showed significant antitumor activity against the ascites form of MH-134 when administered with 5-fluorouracil. These results indicated that OL-2 showed characteristic features regarding its physicochemical properties and antitumor activity.     

Determination of ochratoxin A content in wheat bread samples collected from the Algarve and Bragança regions, Portugal: Winter 2007

Ochratoxin A (OTA) is a mycotoxin produced by fungi such as Penicillium verrucosum and Aspergillium spp. and has been found to have a variety of potentially deadly toxic effects. The favoured substrate for fungal growth and OTA production appears to be cereals and flour-based products, including bread. Due to the dietary relevance of bread for the Portuguese population, it is imperative that its OTA content remains well within safe quantities. As such, bread samples collected from commercial surfaces across the Algarve region and from the city of Bragança during the winter of 2007 were tested for OTA through extraction with immunoaffinity columns and quantification by liquid chromatography coupled with fluorescence detection. Although OTA content was found to be above the limit of quantification in approximately 60% and 50% of the analysed samples from Algarve and Bragança, respectively, all samples were found to be compliant with European Commission. OTA content reached maximums of 0.49 ng/g in Algarve and 0.43 ng/g in Bragança, and was thus below the maximum limit established by European legislation for bread of 3 ng/g. The results of the present study put the estimated daily intake of OTA from bread at approximately 0.26 ng/kg bw/day in Algarve and 0.38 ng/kg bw/day in Bragança, circa 1.5% and 2.0% of the TDI established by either the EFSA or the FAO/WHO, or over 4.5% and 6.5% if we consider the FAO/WHO advised bread consumption of 250 g/day. These results seem to suggest that, in these two Portuguese regions, OTA contamination is well under control and unlikely to represent a threat to consumer health.     

Chemical composition,antioxidant, antibacterial and cytotoxic activities of essential oil of Leontopodium leontopodioides (Willd.) Beauverd

The essential oil (EO) from the aerial parts of Leontopodium leontopodioides (Willd.) Beauverd was obtained by hydrodistillation and analysed by GC–FID and GC–MS. Sixty-five compounds were identified which represent 96.2% of the total composition of the EO. The major components of the EO were palmitic acid (11.6%), n-pentadecanal (5.7%), linalool (3.8%), β-ionone (3.3%), hexahydrofarnesyl acetone (3.2%), bisabolone (3.2%) and β-caryophyllene (3.2%). The EO exhibited an excellent antibacterial activity against Staphylococcus aureus and Bacillus subtilis according to the MIC values tested by micro-dilution method. It also exhibited a significant cytotoxicity against HepG2 and MCF-7 cell lines with the IC₅₀ values of 67.44 and 70.49 μg/mL according to the MTT assay. However, the antioxidant activity test revealed that the EO exhibited a weak DPPH radical-scavenging activity. In conclusion, the EO of L. leontopodioides could be regarded as a bioactive natural product and deserves further study for its potential therapeutic effects.     

Synthesis,structures, electrochemistry and catalytic activities of copper(II) and palladium(II) complexes with asymmetric tetraazacycloannulenes

Copper(II) and palladium(II) complexes with 15-membered asymmetric 5,9-dihydro-2,4,10,12-tetramethyl-1,5,9,13-monobenzotetraazacyclo[15]tetradecine have been synthesized and characterized. The electrochemical behaviors of the complexes showed a reduction and two one-electron irreversible oxidation waves in given potential ranges due to the metal ion and macrocycle ring, respectively. The electrocatalytic reduction of dioxygen on glassy carbon electrodes electropolymerized by such 15-membered and 14-membered tetraazaannulene complexes occurred at 160–280 mV (versus SCE), less negative than on the bared one at pH 7.0. The catalytic activities of the copper(II) complexes in the oxidation of p-Xstyrene (X = OCH₃, CH₃, H, F, Cl) were higher than those of the palladium(II) ones. The structures of the 15-membered copper(II) and palladium(II) complexes were determined using the X-ray diffraction method.     

Comparison of compositions and antimicrobial activities of essential oils from chemically stimulated agarwood, wild agarwood and healthy Aquilaria sinensis (Lour.) gilg trees

The composition and antimicrobial activity of the essential oils which were obtained from agarwood originated from Aquilaria sinensis (Lour.) Gilg stimulated by the chemical method (S1) were characterized, taking wild agarwood (S2) and healthy trees (S3) respectively as the positive and negative controls. The chemical composition of S1 was investigated by gas chromatography-mass spectrometry (GC-MS). The essential oil of S1 showed a similar composition to that of S2, being rich in sesquiterpenes and aromatic constituents. However, the essential oil of S3 was abundant in fatty acids and alkanes. Essential oils of S1 and S2 had better inhibition activities towards Bacillus subtilis and Staphyloccus aureus, compared with essential oil of S3. Escherichia coli was not sensitive to any of them.     

Sebiferone,a New Triterpenoid from Stem Bark of Sapium sebiferum （L.）Roxb.

From the stem bark of Sapium sebiferum a new triterpenoid,anmed sebiferone (1),was isolated.The structure of the new compound was clucidated as 3β-acetoxy-D-friedoolen-14-en-1-one-28-oic acid on the basis of spectral and chemical methods.     

Production, purification, and characterization of a polygalacturonase from a new strain of kluyveromyces marxianus isolated from coffee wet-processing wastewater

A new high polygalacturonase (PG)-producing Kluyveromyces marxianus strain was isolated from coffee wet-processing wastewater. PG production in this strain is not repressed in the presence of 100g/L of glucose and, being growth-associated, reached its maximum accumulation in the culture medium at the beginning of the stationary phase. Oxygen and galacturonic acid negatively regulated enzyme synthesis, and glucose as the carbon source afforded better enzyme yields than lactose. The data reported here show that this strain exhibits the highest index of PG production among the wild-type strains reported so far (18.8U/mL). PG was readily purified by ion-exchange chromatography on SP-Sepharose FF. The activity corresponded to a single protein with an M _r of 41.7 kDa according to sodium dodecyl sulfate polyacrylamide gel electrophoresis. The enzyme was stable in the pH range of 3.0–5.0 and displayed an optimal temperature of 55°C; it showed a typical endo-splitting way of substrate hydrolysis and exhibited a fair degree of activity on pectin with a high degree of esterification.