Foliar application of calcium and magnesium improves growth,yield, and essential oil yield of oregano (Origanum vulgare ssp. hirtum)

Oregano is one of the most important spices, is used all over the world, and includes many species. One of the most important commercially grown species is Origanum vulgare ssp. hirtum (Link) Ietsw (syn.: O. heracleoticum.), which is endemic to the Mediterranean area. O. vulgare ssp. hirtum is a crop species which is well adapted to both dry land conditions and calcareous soils. The objectives of this study were to determine the effects of foliar Ca²⁺ and Mg²⁺ applications on growth, yield, essential oil content, and essential oil yield of oregano. Five treatments (0, 0.5% Ca, 1% Ca, 1% Mg, and 2% Mg) were used, and the experiment was repeated at two locations over two growth periods (2005 and 2006) in northern Greece in a sandy loam and sandy clay soil. Foliar applications with Ca²⁺ and Mg²⁺ increased the Ca²⁺ and Mg²⁺ concentration of the leaves. Ca²⁺ and Mg²⁺ applications affected plant height as the plants were shorter in the control treatment and increased with Ca²⁺ and Mg²⁺ applications by an average of 10% during the 2-year period and at the both locations compared with the control. Also, Ca²⁺ and Mg²⁺ applications increased the number of stems per plant by an average of 23% in both years and at both locations. Chlorophyll concentration was affected by Ca²⁺ and Mg²⁺ applications and subsequently increased an average of 23% with Ca²⁺ and 38% with Mg²⁺ compared with the control. Applications of Ca²⁺ and Mg²⁺ decreased the number of days required for oregano plants to flower by an average of 3–4 days compared with the control. Dry matter yield also increased 22% with Ca²⁺ and Mg²⁺ during the 2-year study and at both locations compared with the control treatment. In addition, the Ca²⁺ and Mg²⁺ applications affected the essential oil yield, but they did not affect the essential oil content. These results show that Ca²⁺ and Mg²⁺ applications can affect the growth and yield of oregano, especially when the plant is grown in acid soils. However, the physiological basis of this effect remains unknown.     

Preparation of electrospun silk fibroin/Cellulose Acetate blend nanofibers and their applications to heavy metal ions adsorption

Silk fibroin (SF)/Cellulose Acetate (CA) blend nanofibrous membranes were prepared by electrospinning and their heavy metal absorbabilities were examined in an aqueous solution after ethanol treatment. The electrospun nanofibrous membranes were comprised of randomly oriented ultrafine fibers of 100–600 nm diameters. As a result of field emission electron microscope (FEEM), the anti-felting properties of the blend nanofibrous membranes were markedly improved after treatment with 100 % ethanol when SF was blended with CA. Metal ion adsorption test was performed with Cu²⁺ as a model heavy metal ion in a stock solution. The SF/CA blend nanofiber membranes showed higher affinity for Cu²⁺ in an aqueous solution than pure SF and pure CA nanofiber membranes. Especially, the blend nanofibrous membranes with 20 % content of CA had an exceptional performance for the adsorption of Cu²⁺, and the maximum milligrams per gram of Cu²⁺ adsorbed reached 22.8 mg/g. This indicated that SF and CA had synergetic effect. Furthermore, the parameters affecting the metal ions adsorption, such as running time and initial concentration of Cu²⁺, had been investigated. The results showed that the adsorption of the Cu²⁺ sharply increased during the first 60 min, the amount of metal ions adsorbed increased rapidly as the initial concentration increased and then slope of the increase decreased as the concentration further increased. This study provides the relatively comprehensive data for the SF/CA blend nanofibrous membranes application to the removal of heavy metal ion in wastewater.     

Enzymatic grafting of lactoferrin onto silk fibroins for antibacterial functionalization

Enzymatic oxidation of tyrosine side-chains in proteins could produce reactive o-quinones that might subsequently react with the primary amino groups of functional compounds, which provided a worthwhile reference for functionalization of fibrion materials. In the present work the potential for using tyrosinase to graft the bovine lactoferrin onto Bombyx mori silk fibroin was examined. Lactoferrin could adsorb onto silk fibers and covalently bind to the previous enzymatically oxidized fibroin surface. The enzyme-generated quinones in silk fibers also might cause self-crosslinking of fibroin peptides, which led to beneficial changes of silk properties. For the fabric treated with tyrosinase and lactoferrin slight improvements of dyeability and strength were obtained in comparison to the control. The combinedly treated fabric showed encouraging resistance to S. aureus and E. coli, the antibacterial activities reached to 87.0 % and 76.4 %, respectively. The durability of the antibacterial silk was noticeably higher than that of the sample treated with lactoferrin alone.     

Benzothiazole-based semisquaraine as colorimetric chemosensor for Hg2+

A highly selective colorimetric chemosensor for Hg²⁺ based on the semisquaraine (BSQ) containing benzothiazole moiety was investigated. BSQ showed color change only with Hg²⁺, but it showed no significant changes upon addition of other metal ions such as Ca²⁺, Pb²⁺, Al³⁺, Ce²⁺, Ba²⁺, Ni²⁺, Cd²⁺, Zn²⁺, and Mg²⁺. Hg²⁺ ions coordinated to the BSQ forming 1:1 complex. The experimental data and conclusions are rationalized by DMol³ calculation results.     

New fluorescent dye chemosensor for mercury ion (Hg2+) detection

The dye chemosensor for mercury ion detection was designed, which was based on donor-acceptor intramolecular charge transfer system and the corresponding fluorescence changing property was successfully monitored. This new dye chemosensor was containing dimethylcarbamodithioate groups to coordinate Hg²⁺, which showed very effective sensing functions. But it showed no significant changes upon the addition of other metal ions such as Ca²⁺, Pb²⁺, Al³⁺, Ce²⁺, Ba²⁺, Ni²⁺, Cd²⁺, Zn²⁺, and Mg²⁺.     

Structural and physical properties ofAntheraea pernyi silk fibroin fiber treated with I2-KI aqueous solution

Silk fibroin (SF) fiber from theAntheraea pernyi silkworm was treated with a 1.23 N iodine-potassium iodide (I₂-KI) aqueous solution, and the structure and physical properties were investigated to clarify the effects of the iodine treatment. The noticeably high weight gain value of SF fiber, about 25 wt% was attributed to the absorption of polyiodide ions in the form of I₃ ^? and I₅ ^?. Fourier transform infrared spectroscopy and X-ray diffraction measurements suggested that polyiodide ions mainly entered the amorphous region. In addition, a new sharp reflection on the meridional direction, corresponding to a period of 7.0 Å, was observed and indicated the possibility of the formation of mesophase structure ofβ-conformation chains. Dynamic viscoelastic measurements showed that the damping tanδ peak at 270°C gradually shifted to lower temperature in the iodinated SF fibers, suggesting an enhancement of the molecular motion of the fibroin chains induced by the presence of polyiodide ions. With heating above 254 °C, the iodine component introduced intermolecular cross-linking of SF, and the melt flow of the sample was inhibited. The thermal decomposition stability of fibroin molecules was greatly enhanced by iodine treatment.     

Relationships between antithrombogenicity and surface free energy of regenerated silk fibroin films

Silk fibroin (SF) was dissolved in calcium chloride/ethanol/water mixture (1/2/8 in mole ratio) at 70°C for 4 h. The dissolved silk fibroin was regenerated by casting the dialyzed solution into the films. The films were treated with 50% aqueous solution of methanol for different times, and their antithrombogenicity was evaluated byin vitro andin vivo tests.In vivo blood tests were made by a method of peripheral vein indwelling suture. It was found that the silk fibroin had a good anti-thrombogenicity and an absorbability even though the polymer showed foreign body reaction. Finally, the blood compatibilty of silk fibroin films which were subjected to structural change by the methanol treatment, was examined in connection with their interfacial surface energy, and a correlation between these properties was found to be present.     

Preparation of poly(acrylonitrile)-grafted silk fibers with antibacterial properties

This study is focused on investigating the feasibility of using silver(I) ions loaded poly(acrylonitrile)-grafted silk fibers as antibacterial dressing material. The optimum grafting conditions for ceric ammonium nitrate induced graft-copolymerization of acrylonitrile onto silk fibers were found to include initiator concentration of 35 mM, catalyst HNO₃ concentration of 0.40 M and initiation time of 10 min. The poly(acrylonitrile)-grafted silk fibers were loaded with silver(I) ions by equilibration method. The resulting fibers were investigated for their biocidal action against E. coli, by using zone inhibition and colonies counting method.     

Preparation and properties of fibers produced from a cellulose/complex PA solvent system precipitating in diverse coagulants

Ethanol, as the first coagulation bath, and several common organic solvents, as well as aqueous solutions of NH₄Cl, NaHCO₃ and NaOH were explored and demonstrated to be adopted as the second coagulation bath for cellulose/phosphoric acid/tetraphosphoric acid (cellulose/complex PA solvent) solution to produce novel cellulose fibers by two-stage dry-wet spinning in a laboratory scale, and effect of coagulants, cellulose concentration, solvent concentration (P₂O₅ concentration) and coagulation temperature on crystal structure and properties of corresponding fibers were investigated. Surface morphology of regenerated fibers as-spun from different coagulants was observed by scanning electronic microscope (SEM), indicating that methanol and 8 wt% NaOH aqueous solution all rendered cellulose fibers relatively dense and smooth surface. X-ray diffraction (XRD) analysis showed that cellulose fiber precipitated from 8 wt% NaOH aqueous solution had pronounced characteristic peak of cellulose II than those of fibers precipitated from other coagulants, and highest crystallinity and orientation. Meanwhile, those two coagulants referred above also gave cellulose fibers relatively higher tensile strength under the same prerequisite. TGA curves exhibited that fibers were thermally stable produced from two salt aqueous solutions (8 wt% NH₄Cl and NaHCO₃) since they had the relatively higher onset decomposition temperatures. By evaluating the effect of cellulose concentration, P₂O₅ concentration and coagulation temperature on the structure and properties of asprepared fibers, it was preferable to produce cellulose fiber from a solution at 20 wt% cellulose concentration, 73 % P₂O₅ concentration, and coagulating in methanol at coagulation temperature of 60 °C at the second-stage.     

Characterization of an Insoluble and Soluble Form of Melanin Produced by Streptomyces cavourensis SV 21, a Sea Cucumber Associated Bacterium

Melanin is a widely distributed and striking dark-colored pigment produced by countless living organisms. Although a wide range of bioactivities have been recognized, there are still major constraints in using melanin for biotechnological applications such as its fragmentary known chemical structure and its insolubility in inorganic and organic solvents. In this study, a bacterial culture of Streptomyces cavourensis SV 21 produced two distinct forms of melanin: (1) a particulate, insoluble form as well as (2) a rarely observed water-soluble form. The here presented novel, acid-free purification protocol of purified particulate melanin (PPM) and purified dissolved melanin (PDM) represents the basis for an in-depth comparison of their physicochemical and biological properties, which were compared to the traditional acid-based precipitation of melanin (AM) and to a synthetic melanin standard (SM). Our data show that the differences in solubility between PDM and PPM in aqueous solutions may be a result of different adjoining cation species, since the soluble PDM polymer is largely composed of Mg²⁺ ions and the insoluble PPM is dominated by Ca²⁺ ions. Furthermore, AM shared most properties with SM, which is likely attributed to a similar, acid-based production protocol. The here presented gentler approach of purifying melanin facilitates a new perspective of an intact form of soluble and insoluble melanin that is less chemical altered and thus closer to its original biological form.     

磷对NaCl胁迫下玉米幼苗渗透调节能力的影响

研究不同供磷水平对NaCl胁迫下玉米幼苗有机渗透调节物质和离子含量的影响。结果表明,盐胁迫下低磷处理玉米幼苗叶片中可溶性糖和游离氨基酸增加,根系中显著降低;增加供磷水平,叶片中可溶性糖和游离氨基酸含量下降,根系中含量上升,同时叶片和根系中可溶性蛋白含量增加。磷可降低盐胁迫下玉米幼苗各器官中的Na~+含量,同时增加各器官的K~+、Ca~(2+)和Mg~(2+)含量,降低Na~+/K~+与Na~+/Ca~(2+)比值。磷有助于维持植株的碳氮代谢平衡,促进有机渗透调节物质的运输与分配,改善各器官的离子平衡,增强植株的渗透调节能力,从而缓解盐胁迫带来的伤害。     

Preparation and characterization of bacterial cellulose/hydroxypropyl chitosan blend as-spun fibers

In the work, N-methylmorpholine-N-oxide monohydrate (NMMO·H₂O) was used as a solvent to solve bacterial cellulose (BC) and hydroxypropyl chitosan (HPCS) together, and regenerated bacterial cellulose (RBC)/HPCS blend as-spun fibers were prepared by blending BC with HPCS via wet-spinning in the Lyocell process. Structure and properties of the blend as-spun fibers were characterized by different techniques, together with the antibacterial activity of the blend as-spun fibers against Staphylococcus aureus. Results revealed that HPCS was mixed with BC very well. The blend as-spun fibers showed a rough and folded surface morphology and an interior pore structure on the cross-section. Compared with pure RBC as-spun fibers, the blend as-spun fibers had lower degree of crystallinity and thermal stability. Although extension at break of the blend as-spun fibers was lower than the pure RBC as-spun fibers, their tensile strength and modulus had been enhanced obviously. The blend as-spun fibers were also found to exhibit excellent antibacterial activities against S. aureus.     

Study on coloration of silk based on coupling reaction with a diazonium compound

This paper describes how coloration of silk can be achieved using a coupling reaction between a diazonium compound, made from Color Base Red G (C.I. 37105) and tyrosine residues in the silk protein fibroin. A pigment with an azo structure obtained from the reaction between the diazonium of Color Base Red G with p-methylphenol was synthesized and studied as a model compound for the coloration reaction. The colored materials were characterized using UV-vis, FT-Raman, FT-IR, ¹H-NMR, and mass spectroscopy. Both the colored silk and the model compound gave yellow colors with absorption maxima in the region of 400 nm. The results suggest that the use of coupling reactions could be developed into a dyeing method for protein fibers or other protein materials that contain tyrosine residues. Because the chromophores are incorporated into the protein chains, such dyed silks should have good wet fastness properties.     

Silk grafting with chitosan and crosslinking agents

Chitosan grafting onto silk was tested with three crosslinking agents: trifunctional epoxy resin Araldite DY-T, PEG400 dimethacrylate, and glutaraldehyde in acetic as well as in tartaric acid solutions. Operating conditions were studied to obtain a significant silk weighting with satisfactory graft yields. With the epoxy crosslinker the weight gain was in the range from 1.8 to 8.8 % with graft yield from 8 to 23 %. In the case of PEG400DMA weight gain was 8–12 % with 22–24 % graft yield. With glutaraldehyde in tartaric acid solution a maximum weight gain of 8.4 % with 27.6 % graft yield was obtained. Results of determination of primary amino groups on the grafted silk showed that with epoxy and glutaraldehyde, unlike PEG400DMA, the amino groups of chitosan were only partially involved in crosslinking. Results of DSC analyses suggested that the modification of fibroin structure in chitosan-grafted silk was stronger with glutaraldehyde than with epoxy or dimethacrylate. FTIR-ATR spectra of grafted fibers were found very similar to that of control silk with an additional weak peak ascribable to chitosan in 1180–1080 cm⁻¹ range. Surface investigation through AFM showed clear morphology differences between chitosan-grafted silk with epoxy or dimethacrylate and that crosslinked with glutaraldehyde; the latter appears uneven and scale-like, the others slightly rougher than the original silk.     

Preparation and characterization of silver-loaded hemp fibers with antimicrobial activity

The objective of this research was to impart antimicrobial properties to hemp fibers by incorporation of silver ions in hemp fibers by chemisorption. Sorption properties of hemp fibers were improved by non-selective oxidation using hydrogen peroxide and potassium permanganate. The optimal conditions for silver ions sorption by hemp fibers were determined by changing sorption conditions: pH value and concentration of aqueous silver nitrate solution, as well as duration of sorption. The maximum sorption capacity of modified hemp fibers was 1.84 mmol of Ag⁺ ions per gram of fibers. Antimicrobial activity of silver-loaded hemp fibers against different pathogens: Staphylococcus aureus, Escherichia coli, and Candida albicans was evaluated in vitro. Obtained silver-loaded hemp fibers show antimicrobial activity against tested pathogens.     

Electrospinning of silk nanofibers. I. An investigation of nanofiber morphology and process optimization using response surface methodology

Ultra fine fibers were electrospun from regenerated silk fibroin/formic acid solution. Effect of some process parameters on the morphology, diameter and variation in fiber diameter of electrospun fibers were experimentally investigated. Scanning electron microscope was used for the measurement of fiber diameter. Fibers with diameter ranging from 80 to 210 nm were collected depending on the solution concentration and the applied voltages. Response surface methodology (RSM) was used to obtain a quantitative relationship between selected electrospinning parameters and the average fiber diameters and its distribution. It was shown that concentration of silk fibroin solution had a significant effect on the fiber diameter and the standard deviation of the fiber diameter. Applied voltage had no significant effect on the fiber diameter and its standard deviation.     

Effects of incubation times and moisture regimes on pH values and exchangeable cations in acid sulfate soils as influenced by application rates of basic slag

Severe acidifications in acid sulfate soils (ASSs) have occurred worldwide due to sulfuric acidity, which requires sustainable measures for their reclamation. Accordingly, an incubation study was conducted with the topsoil of two different ASSs (Cheringa and Badarkhali) to evaluate the effects of basic slag (BS; size <1 mm, pH 9.6, Ca 20.8%, Mg 9.8%, etc.), on reduction of acidity and changes in exchangeable cations. It is noted that BS is a byproduct of steel industry in Bangladesh and can be collected almost free of charge. These soils received BS at the rate of 0 (T₀), 11 (T₁), 22 (T₂) and 33 (T₃) t ha⁻¹ under various moisture regimes (saturated condition M₁,_, i.e., 100% moisture content, wetting–drying cycles of 100 and 50% moisture M_2, and moisture at field condition M₃, i.e., 50%). The impacts of these treatments on some selected parameters in these soils were studied within 180 days of incubation. The application of BS was found to increase the pH of soils from 3.6 to 5.1 for Cheringa, 3.9 to 5.2 for Badarkhali soils at the end of incubation. These increments were more striking with the highest doses of BS under saturated moisture conditions in both of the soils. The ECe of the soils was not much influenced by the application of BS regardless of time. The treatments exerted significant (P ≤ 0.05) effects on exchangeable cations in different periods of incubation. The striking changes were recorded for the rate of increments of Ca²⁺ and Mg²⁺, which were about 2–3 times higher for Ca and more than 2 times higher for Mg²⁺ compared with the control after 180 days of incubation. These results suggest that the application of BS not only increased the Ca²⁺ to the higher amount than that of the increment of Mg²⁺ in the soils, but also improved one of the important criteria of Ca²⁺ and Mg²⁺ ratio in the soils.     

Mineral binding capacity of dephytinized insoluble fiber from extruded wheat,oat and rice brans

Insoluble fiber fractions from raw and extruded oat, rice and wheat brans were isolated and phytate removed. In vitro mineral binding studies were performed utilizing copper (Cu²⁺), calcium (Ca²⁺) and zinc (Zn²⁺) ions, which were added individually to enzymatically treated (Prosky et al., 1985), acid washed insoluble fiber residues from oat, rice and wheat brans. The enzymatic digestion step with alpha-amylase, protease and amyloglucosidase served to remove protein and starch from the samples. Mineral binding studies were performed on the insoluble fiber residue. Mineral content was determined by flame atomic absorption spectroscopy. Raw brans served as controls. A twin-screw extruder Model DNDG-62/20D, manufactured by Bühlerag (CH-9240, Uzwil, Switzerland) was utilized. The objectives of the study were to determine the total Cu²⁺, Ca²⁺ and Zn²⁺binding capacity of the dephytinized insoluble fiber from each bran; and to determine if extrusion screw speed affected the brans' insoluble fiber mineral binding capacity. Although dephytinized, the brans' insoluble fiber fraction bound Cu²⁺, Ca²⁺ and Zn²⁺ions. Oat bran bound more Cu²⁺, Ca²⁺ and Zn²⁺ than wheat bran, which bound more than rice bran. Extrusion processing did not affect the brans' insoluble fiber binding capacity to bind Cu²⁺. However, it increased the binding capacity of Ca²⁺ and Zn²⁺ of the insoluble fiber fraction from rice and oat brans.     

钙对铬胁迫下玉米幼苗生长及生理特性的影响

采用含有CrCl3及CaCl2的培养液培养,研究了不同浓度钙和铬处理对玉米幼苗的叶片、株高、根长、鲜重、含水量、叶绿素、保护酶系统(SOD、POD、CAT活性)以及丙二醛(MDA)含量的影响。结果表明,单一铬处理,随着铬浓度增加,玉米植株生长明显受到抑制,株高、根长、鲜重、含水量、叶绿素含量以及CAT活性下降,SOD、POD活性上升,MDA含量增加。单一钙处理,当浓度小于160 mg/L时,明显促进植株生长,株高、根长、鲜重、含水量、叶绿素含量增加,CAT活性上升,POD活性和MDA含量下降;当钙浓度大于160 mg/L时促进效果则开始下降。钙、铬混合处理,一定浓度的钙有抑制或者缓解铬毒害的作用,减轻铬胁迫对株高、根长、鲜重和含水量的抑制,提高叶绿素含量和CAT活性,降低SOD、POD活性和MDA含量。     

1-Aminoanthraquinone Diazonium Salt on the Coupling Modification Dyeing of Silk Fibroin with Enhanced Color Fastness

Chromophore incorporated into the protein chains through residue modification on silk fibroin will be an important way to get new dyeing technology with improved color fastness. Herein, 1-aminoanthraquinone diazonium salt was prepared and used for the modified dyeing on tyrosine of silk fibroin. The silk after modified dyeing was measured by UV-Vis, FTIR, MS, ¹H-NMR, Data color, and other testing techniques. Interestingly, the resulting silk showed excellent rub and wash fastness. The enhanced color fastness is contributed by an electrophilic substitution reaction between 1- aminoanthraquinone diazonium salt and the ortho position of phenolic hydroxyl in tyrosine molecular. Moreover, the mechanical property of silk was protected effectively by the mild coupling modified dyeing, better than the traditional acid dyeing under high temperature for a long time. This facile strategy provides an alternative approach to silk dyeing and benefits the silk applications.