Addition Of AgNO3 Research Articles

Optimization of mature embryo‐based high frequency callus induction and plant regeneration from elite wheat cultivars grown in China

AbstractWe have developed an efficient procedure for plant regeneration of elite wheat cultivars using mature embryos. Firstly, we established the optimal combination of basal media, inoculation method and pretreatment method using biostatistical methods. The results indicated that the combination of MS medium and longitudinally bisected mature embryos showed the highest culture efficiency, whereas the pretreatment method had no significant effects on callus induction or plant regeneration. A 70% primary callus induction rate was achieved on MS medium containing 2 mg/l 2,4‐d for all tested cultivars. Primary calli were then transferred onto the subculture medium to initiate embryogenic calli. Supplementation of the subculture medium with the appropriate combination of phytohormones (2.0 mg/l 2,4‐d, 0.5 mg/l BA and 0.1 mg/l NAA) significantly enhanced embryogenic callus production. The addition of AgNO3 (10 mg/l) in regeneration medium promoted plant regeneration, whereas CuSO4 stimulated root formation. The use of this protocol achieved successful plant regeneration in eight tested cultivars. The culture efficiency ranged from 15.3% to 36.8%, suggesting this regeneration system may be an effective alternative for wheat genetic transformation.

Geochemistry of Flooded Underground Mine Workings Influenced by Bacterial Sulfate Reduction

Unlike the majority of the water in the flooded mine complex of Butte Montana, which includes the highly acidic Berkeley pit lake, groundwater in the flooded West Camp underground mine workings has a circum-neutral pH and contains at least 8 μM aqueous sulfide. This article examines the geochemistry and stable isotope composition of this unusual H2S-rich mine water, and also discusses problems related to the colorimetric analysis of sulfide in waters that contain FeS(aq) cluster compounds. The West Camp mine pool is maintained at a constant elevation by continuous pumping, with discharge water that contains elevated Mn (90 μM), Fe (16 μM), and As (1.3 μM) but otherwise low metal concentrations. Dissolved inorganic carbon in the mine water is in chemical and isotopic equilibrium with rhodochrosite in the mineralized veins. The mine water is under-saturated with mackinawite and amorphous FeS, but is supersaturated with Cu- and Zn-sulfides. However, voltammetry studies show that much of the dissolved sulfide and ferrous iron are present as FeS(aq) cluster molecules: as a result, the free $$ {\hbox{H}}_{\hbox{2}} {\hbox{S}}\,{\hbox{ + }}\,{\hbox{HS}}^{\hbox{ - }} $$ concentration of the West Camp water is poorly constrained. Concentrations of dissolved sulfide determined by colorimetry were lower than gravimetric assays obtained by AgNO3 addition, implying that the FeS(aq) clusters are not completely extracted by the Methylene Blue reagent. In contrast, the clusters are quantitatively extracted as Ag2S after addition of AgNO3. Isotopic analysis of co-existing aqueous sulfide and sulfate confirms that the sulfide was produced by sulfate-reducing bacteria (SRB). The H2S-rich mine water is not confined to the immediate vicinity of the extraction well, but is also present in flooded mine shafts up to 3 km away, and in samples bailed from mine shafts at depths up to 300 m below static water level. This illustrates that SRB are well established throughout the southwestern portion of the extensive (>15 km3) Butte flooded mine complex.

Optimization of abiotic factors for improved growth and extracellular production of recombinant fungal phytase in sesame hairy root cultures

The effects of various abiotic factors, including polyethylene glycol (PEG), silver nitrate (AgNO3) and potassium phosphate (KH2PO4) on biomass growth, extracellular production of recombinant fungal phytase and its transcription activity by realtime RT-PCR were examined with transformed sesame hairy roots. The PEG treatments decreased both biomass growth (80.5≈82.3%) and phytase production (82.1≈96.4%) at all concentrations tested, except 1.0 g/L PEG, which increased biomass growth to 112.4% of that of the control. The AgNO3 treatments also resulted in reduced biomass growth (77≈92%) and phytase production (84.4≈96.3%) at all concentrations applied except 1.5 mg/L AgNO3, at which biomass was increased to 109.6% of that of untreated roots. The potassium phosphate treatments increased biomass growth, production of recombinant fungal phytase and its transcription until a concentration of 340 mg/L was attained, and at 510 mg/L a rapid decrease was observed in all of the aforementioned parameters. Combined treatments of PEG (1 g/L) and AgNO3 (1.5 mg/L) exhibited both positive and negative influences on biomass growth and production and transcription of the recombinant fungal phytase when medium containing 170 and 340 mg/L of potassium phosphate were used, respectively. The addition of PEG alone to culture medium containing potassium phosphate at both of the aforementioned concentrations decreased biomass while increasing production and transcription of recombinant fungal phytase. Conversely, the addition of AgNO3 alone to culture medium increased biomass but decreased production and transcription of fungal phytase. Throughout these experiments, the most effective treatment for enhanced biomass growth, and enhanced production and transcription of recombinant fungal phytase was attained when the 1 g/L PEG and 1.5 mg/L AgNO3 were combined in medium containing 340 mg/L potassium phosphate.

Solvent effects on the reactions of copper chlorides with OP(NH-t-Bu)3 — Formation of the novel [Cu5Cl10]5– anion via in situ templation

X-ray structural investigations have shown that the products of the reaction of CuCl2·2H2O and OP[NH-t-Bu]3 are markedly dependent on solvent and temperature. The polymeric ionic complex [(t-BuNH3)2(Cu3(OH)(H2O)Cl7)]∞ (1), containing a trinuclear anionic repeating unit, is obtained from toluene at 80 °C, whereas the 2:1 adduct Cu(t-BuNH2)2Cl2 (4) is formed at 150 °C. By contrast, a neutral tetranuclear cluster Cu4[PO(NH-t-Bu)3]4(µ4-O)Cl6 (2) or the one-dimensional chain [Cu(Py)2Cl2]∞ (3) is produced when the reaction is carried out in hexane or pyridine, respectively, at 80 °C. The reaction of a mixture of CuCl and CuCl2·2H2O (2:1 molar ratio) with OP[NH-t-Bu]3 at 80 °C in toluene produces [t-BuNH3]5[Cu5Cl10] (5), in which the anion is a pentanuclear cluster with both terminal and bridging chloride ions. The removal of the chloride ions from the reaction mixture by the addition of AgNO3 yields the 2:1 adduct Cu[OP(NH-t-Bu)3]2(NO3)2 (6).Key words: copper halides, templation, P–N compounds, cluster complexes, one-dimensional framework

Effects of silver nitrate on the tissue culture of immature wheat embryos

The immature embryos of four common wheat (Triticum aestivum L.) genotypes with desirable agronomic traits were evaluated for their tissue culture response to ethylene antagonist, silver nitrate, added to callus-inductive and subculture media at six concentrations. The addition of AgNO3 significantly improved embryogenic callus frequency and callus growth, but reduced the necroses and almost did not affect callus induction frequencies. Strong genotypic effects on callus induction, embryogenic callus formation, and necrosis frequency were observed. It was also found that there were significant interactions between genotype and AgNO3 concentrations affecting embryogenic callus frequency and callus growth index. In general, 10 mg/l concentration may be considered most favorable for embryogenesis and prevention of necroses; at the same time, it did not reduce callus induction and promoted callus growth.

Preparation of Red Long Afterglow Phosphorescent Material CaTiO<sub>3</sub>: Pr<sup>3+</sup>

CaTiO3:Pr3+ was prepared by high temperature solid state reaction and measured by SEM, XRD, excitation and emission spectra. The samples obtained possessed orthorhombic crystal structure of CaTiO3, belonging to Pbnm space group. Excitation spectra of the samples were broad band, their peaks and shoulder peaks were located at about 335nm, 379nm respectively. Emission spectra were single narrow band, emission peaks were located at about 602nm, corresponding to emission of 1D2→3H4 of Pr3+ion. The addition of Eu3+and Dy3+ as co-activator led phosphorescent intensity to greatly enhance, the addition of AgNO3 as ion compensator made the samples material pink and vibrant.

Silver nitrate and aminoethoxyvinylglycine affect Agrobacterium-mediated apple transformation

In Fuji, the production of ethylene was increased with the addition of AgNO3 and inhibited with the addition of 10 μM aminoethoxyvinylglycine (AVG). The addition of 80 μM AgNO3 to transformed explants of ‘Fuji’ cultured on selection medium resulted in increased ethylene production (20 μl l−1) at 3 weeks. Under examining the effect of AgNO3 in ‘Fuji’, the 40 μM AgNO3 showed with higher 33.8% and 6.5% in the efficiency of regeneration and transformation. However, ethylene production in ‘Gala’ explants treated with 10μM AgNO3 (3 μl l−1) decreased after 2 weeks compared with the control (5 μl l−1). Although the regeneration efficiency of ‘Gala’ with 10 μM AgNO3 was higher (41.1%) than the control (20.1%), there was no significant difference in the transformation efficiency at the same concentration. Shoot regeneration of ‘Fuji’ and ‘Gala’ was completely inhibited with 10 μM AVG. These results suggest that the addition of AgNO3 affects the efficiency of Agrobacterium-mediated gene transfer in ‘Fuji’.

The influence of noble-metal-containing cathodes on the electrochemical performance of anode-supported SOFCs

In order to enhance the catalytic activity of the cathode for oxygen reduction and thus to increase the electrochemical performance of planar anode-supported solid oxide fuel cells, Pd, Ag, or Pt was added to the cathode. Four routes were used to add these noble metals: infiltration of the cathode with a Pd solution, deposition of Pt on the electrolyte surface, mixing of La0.65Sr0.30MnO3 (LSM) and YSZ cathode powders with different metal precursors (Pt and Pd black, Pd on activated carbon, Ag powder, Ag2O, Ag acetate, Ag citrate, Ag2CO3, colloidal Ag, AgNO3), and synthesis of LSM powder with the addition of AgNO3. Between 750 and 900 °C no electrocatalytic effect occurred with respect to the presence of Pt, either added by deposition on the electrolyte or by mixing with cathode powders. Infiltration of the cathode with a Pd solution or mixing with Pd black did not result in a positive effect either. A catalytic effect was only found with Pd on activated carbon and in particular at lower temperatures. Cells prepared with Ag powder and Ag2O showed an improved electrochemical performance compared to Ag-free cells sintered at the same temperature (920 °C). However, in comparison to Ag-free cells sintered at the standard temperature (1100 °C) lower current densities were measured. This can be explained by a weak contact between electrolyte and cathode functional layer and an insufficiently sintered cathode. A detrimental effect was observed regarding the addition of the other Ag precursors. Thermal decomposition of these precursors resulted in the formation of large pores in the cathode.

Rapid propagation of Holostemma ada-kodien Schult., a rare medicinal plant, through axillary bud multiplication and indirect organogenesis

Efficient protocols of axillary bud multiplication and indirect organogenesis were established for Holostemma ada-kodien Schult. (Asclepiadaceae). Murashige and Skoog (MS) medium supplemented with 2.0 mg l–1 N6-benzylaminopurine (BAP) and 0.5 mg l–1 indole-3-butyric acid (IBA) induced an average of eight shoots per node and was the best for axillary bud proliferation. Subsequent cultures enhanced the number of shoots. The explant source of callus and the growth regulator inducing the callus exhibited significant influence on organogenesis. Callus developed from the basal cut end of the node explants differentiated more than 15 shoots on MS medium fortified with 1.5 mg l–1BAP. Callus from internode explants developed fewer shoots than callus from the basal cut ends of node explants. Leaf-derived callus did not undergo organogenesis. The abscission of leaves and shoot tips of the developed shoots was prevented by the addition of AgNO3 or CoCl2, but with a concomitant significant reduction in the number of shoots. Half-strength solid MS or liquid medium with 0.05 mg l–1 IBA exhibited the best in vitro rooting. Ninety percent of the rooted shoots survived in the field.

Effect of AgNO3 additive/doping on microstructure and superconductivity of the Pb doped Hg: 1223 thin film prepared through spray pyrolysis

We report successful fabrication of Ag doped Hg:1223 films by reacting Ba2Ca2.3Cu3.3Oz(Agy): y=0, 0.02, 0.025, 0.05, 0.1 and 0.2 precursors deposited by spray pyrolysis on SrTiO3 (100) substrates, in controlled Hg+Pb ambient, in an evacuated sealed quartz tube at 820°C for 4h. The effects of AgNO3 addition on the superconducting properties of Hg/(Pb):1223 films are studied. The addition of low concentration of silver e.g. y≈0.025 results in a slight increase in Tc (R=0) from 125 to 126K and the dc critical current density (Jc) decreases with the increasing Ag in Hg(Pb):1223 (Agy) films. The microstructural details exhibit the curious characteristics of spiral like features for lower concentrations of silver i.e. up to y=0.05. These improvements are believed to be due to the liberation of oxygen through the dissociation of AgNO3 at higher temperature and passivation of weak link effects through the segregation of silver at these grain boundaries. The addition of silver content y≥0.05 resulted in the decrease in transition temperature. The Jc is observed to decrease steadily with increasing Ag content. The microstructural features, e.g. spiral are also found to deteriorate with increasing silver content. The deterioration in superconducting properties at high Ag content is believed to be mainly due to the formation of Ag–Hg amalgam.

Efficient in vitro plant regeneration from immature zygotic embryos of pearl millet [Pennisetum glaucum (L.) R. Br.] and Sorghum bicolor (L.) Moench

We report here an in vitro culture system that provides reliable, highly efficient regeneration from immature embryos of pearl millet [Pennisetum glaucum (L.) R. Br.] and sorghum [Sorghum bicolor (L.) Moench]. Immature embryos were isolated 10-20days after pollination and cultured on various L3 media. The influence of different parameters during the callus induction phase was examined with respect to the regeneration rate: (1) the concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) and various cytokinins; (2) the addition of AgNO3; (3) the use of maltose or sucrose as a carbon source. Modifications in the phytohormones alone resulted in the regeneration of fertile sorghum plants at high efficiency. Significant increases in the regeneration rates of pearl millet genotypes were achieved by the combination of sucrose as a carbon source and silver nitrate as a potential ethylene inhibitor.

In Situ Complex Formation of Long-Chain Schiff Bases with Silver(I) Ion in Monolayers and Their Langmuir−Blodgett Films

The in situ complex formation between two novel long-chain Schiff bases with Ag(I) ion at the air/water interface and their transferred Langmuir−Blodgett films were investigated. The long-chain Schiff bases containing heteroaromatic benzimidazole (BSC18) and benzthiazole (TSC18) rings form stable monolayers at the air/water interface. Addition of AgNO3 in the subphase caused the complex formation of the Schiff base with Ag(I). The Schiff base containing benzthiazole group formed a 1:1 complex with Ag(I). Regular layer structures are formed in the LB films of the Schiff base ligand and Ag(I) complex. The TSC18−Ag(I) complex showed orange color, which was specific only for the combination of TSC18 and Ag(I). X-ray photoelectron spectrum (XPS) of the transferred LB film revealed that a 1 (BSC18):2 (Ag(I)) complex was formed in the case of BSC18, which was explained by the coordination of Ag(I) ion with imine and OH and with benzimidazole. While the LB film of BSC18 showed a well-defined layer structure, that of the Ag(I) complex did not.

Improvement of embryogenic callus induction and shoot regeneration of buffalograss by silver nitrate

Addition of the ethylene antagonist, silver nitrate (AgNO3), into callus induction medium significantly enhanced embryogenic callus production (both induction frequency and callus growth) of field-collected male immature inflorescence cultures of buffalograss NE84-45-3 and 'Texoka'. No stimulatory effect of AgNO3 was observed on embryogenic callus induction for female immature inflorescence culture of a female genotype `609' and `Texoka'. Calli initiated on AgNO3-containing media had more shoot-regenerating calli than those initiated on AgNO3-free media, when they were transferred to the regeneration media. Benzyladenine at 2.2 μM gave the best response for regeneration, regardless of the callus source. Although average number of shoots regenerated per callus was lower for calli initiated on AgNO3-containing media, total number of shoots regenerated was higher. The stimulatory effect, however, was environment and genotype dependent. While the addition of AgNO3 significantly stimulated embryogenic callus induction of NE84-45-3 immature inflorescences collected in Fall 1995 and May 1997, it only slightly increased the embryogenic callus induction frequencies in May 1996 when rainy conditions occurred. For male inflorescences of `Texoka' collected in early May, AgNO3 significantly enhanced embryogenic callus production consistently over the two-year period (1996, 1997).

Investigations on Tl-2223 thin films fabricated through ultrasonic spray pyrolysis under oxygen deficient conditions

In this paper we have shown that polycrystalline films corresponding to Tl-2223 phase can be grown by employing high thalliation temperatures and short thalliation times. Ultrasonically deposited precursor films corresponding to Ba2Ca2.2Cu3.3Ox(Agy) have been thalliated under high vacuum (∼ 10-5 torr) at 890°C to obtain single phase Tl-2223 films. An off-stoichiometric and unreacted pellet of composition Tl2.05Ba2Ca2Cu3Oz has been used as source of Tl. We have shown that oxygen ambient is not necessary for the growth of Tl-2223 phase. The as-thalliated films have Tc’s in the range 123 K ±0.70 K. TheT c has been found to be independent of the addition of AgNO3 to the precursor. The zero field transportJ c has been observed to be > 1.2 X 105 A/cm2 at 77 K. NearT c (110 K-122 K),J c has been observed to follow the power lawJ c ∞ (1-T/T c )p,p 2. A power law withp tt 1.4 has been observed for the temperature range 70 K-110 K. An optimum doping of Ag has been observed to induce about 25% increase inJ c and it also leads to uniform and enlarged grain growth. The surface morphology of Ag free samples contains plate like grains having arbitrary shapes. In contrast to this 0.35 Ag doped sample exhibits nearly rectangular plate like grains

Control of microbial contamination for large-scale photoautotrophic micropropagation

Photoautotrophic (sugar-free) micropropagation has been examined for many different plant species. One of the advantages of photoautotrophic micropropagation is the low risk of contamination, which facilitates the use of large culture vessels, and thus contributes to the reduction in production cost. In this article, pathogenic and nonpathogenic contaminations are discussed, and guidelines for development of large-scale, pathogen-free, photautotrophic micropropagation systems are introduced. A preliminary experiment was conducted for producing pathogen-free plantlets by large-scale photoautotrophic micropropagation. Addition of AgNO3 in the medium was shown to suppress growth of nonpathogenic contaminants without reducing fresh and dry weight, and number of leaves of the tomato plantlets.

Structural Variation in Novel Double Salts of Silver Acetylide with Silver Nitrate: Fully Encapsulated Acetylide Dianion in Different Polyhedral Silver Cages

The reaction of silver acetylide with silver nitrate at 80 °C yielded a mixture of the known compounds Ag2C2·6AgNO3 (1) and Ag2C2·5.5AgNO3·0.5H2O (2), which have different crystal habits and could be manually separated. Ag2C2·5AgNO3 (3) was obtained serendipitously as a mixed product together with 1 from the addition of AgNO3 to a solution of the double salt of Ag2C2 with CF3COOAg at 80 °C. Ag2C2·AgNO3 (4) was obtained by carrying out a hydrothermal reaction at 105 °C. Complexes 2 and 3 contain a monocapped octahedral silver cage and a monocapped trigonal prismatic silver cage, respectively, each fully entrapping an acetylide dianion. In complex 4, silver octahedra each encapsulating an acetylide dianion are connected by linking their equatorial edges along the a and b directions to form a slab, and the sharing of apexes between adjacent slabs along the c direction then generates a three-dimensional network. The bonding interaction between the acetylide dianion, which exhibits triple-bond character, and t...

New sugar-based gelators with an amino group, the gelation ability of which is remarkably reinforced by the hydrogen bond and the metal coordination

Three sugar-integrated gelators bearing a p-aminophenyl group which are expected to exert a hydrogen-bonding effect and a metal coordination effect on the gelation ability were synthesised. -D-Galactose-based 2b was only soluble or precipitated and -D-glucose-based 4b gelated only two of 15 solvents tested herein whereas -D-glucose-based 1b acted as an excellent gelator which could gelate 8 solvents. The sol–gel phase-transition temperature (Tgel) values for 1b were higher by 41–78 °C than those for -D-glucose-based 1a bearing a p-nitrophenyl group. The spectral studies indicated that this gel reinforcement is due to the hydrogen-bonding interaction including the amino group. The Tgel values for the ethanol gel of 1b were markedly improved by the addition of AgNO3, CoCl2 or CdCl2. The detailed examination of a 1b + CoCl2 gel system in ethanol showed that the gel is stabilised by the cross-link of 1b molecules by the Co(II)–amino group interaction. This is the first and a convenient method for the metal reinforcement of organic gels.

Somatic embryogenesis and plant regeneration in Heracleum candicans Wall

A protocol has been developed for achieving somatic embryogenesis and plant regeneration from petiole-derived callus of Heracleum candicans Wall. Callus was initiated on MS medium supplemented with 0.5 mg l-1 2,4-D and 0.5 mg l-1 BAP and subcultured on a medium containing double strength MS macrosalts, 1 mg l-12,4-D and 0.25 mg l-1 Kn. Numerous globular embryos were formed on the surface of the callus upon transfer to auxin-rich MS medium that lacked cytokinins. The globular embryos differentiated into mature embryos only when 2,4-D was removed from the medium. Mature embryo formation was significantly influenced by the pH of the medium and the addition of AgNO3 and ABA. Eighty-five percent of the somatic embryos were converted into plantlets when transferred to a medium supplemented with 0.01 mg l-1 BAP and 0.01 mg l-1 IBA. The regenerated plants have been established in soil and appear to be identical to the parent plants in morphology and chromosome number.

Medium and genotype factors influencing shoot regeneration from cotyledonary explants of Chinese cabbage (Brassica campestris L. ssp. pekinensis).

Medium conditions for reliable shoot regeneration from cotyledonary explants of Chinese cabbage were examined. Maximum shoot regeneration was obtained in the presence of 5 mg/l BA and 0.5 mg/l NAA. Shoot induction was further improved by the addition of AgNO3 as well as higher concentrations (1.2-1.6%) of agar in the regeneration medium. When 123 genotypes were tested, a large variation in regeneration frequency was observed, ranging from 95% to 0%. Shoot regeneration frequency was not related to origin and days to maturity of the genotypes. Ethylene production from cultured explants seemed to play an important role in shoot regeneration. Explants of highly responsive genotypes or if cultured on the medium solidified with a higher concentration of agar generally showed low levels of ethylene production. However, AgNO3, which also enhanced shoot induction, resulted in an increase in ethylene production. The possible interaction between ethylene and shoot regeneration is discussed.

Plant Regeneration of Hot Pepper (Capsicum annuum L.) and Expression of Mouse Adenosine Deaminase (ADA) Gene via Agrobacterium-mediated Transformation

Since in vitro regeneration and transformation systems in hot pepper (Capsicum annuum L.) have not been available, the application of new genetic manipulations has been limited. Here we report an efficient procedure to regenerate whole pepper plants and to generate transgenic plants expressing a foreign gene was established. High frequency of plant regeneration was observed when hypocotyl and cotyledon explants were cultured on MS/B5 medium supplemented with NAA 0.05 mg·L–1 plus zeatin 2.0 mg·L–1, NAA 0.05 mg·L–1 plus zeatin 2.0 mg·L–1, IBA 10.0 mg·L–1 plus BA 1.0 mg·L–1, IAA 0.02 mg·L–1 plus zeatin 3.0 mg·L–1. An addition of AgNO3 5–10 μm to these media improved the regeneration rate by about 10%. For plant transformation, hypocotyl and cotyledon explants of pepper were preconditioned on kanamycin-free shoot induction medium for 48 hours. Then, co-cultivation with Agrobacterium tumeaacience was done on the co-culture medium for 2 days. The explants were then blotted in sterile filter paper and placed on shoot induction and selection medium containing kanamycin sulfate (100 mg·L–1) and carbenicillin (500 mg·L–1). PCR showed that the introduced ADA gene was integrated and stably expressed in the regenerated plants. ADA enzyme activities were checked by spectrophotometric analysis.